WO2021207783A1 - Methods for processing polysulfide polymers - Google Patents

Abstract

A process for preparing a unitary polysulfide polymer containing article is disclosed. The process comprises contacting a plurality of article subunits containing a polysulfide polymer with one another under reaction conditions to cause sulfur-sulfur exchange reactions to occur between article subunits to thereby form the unitary polysulfide polymer article.

Description

METHODS FOR PROCESSING POLYSULFIDE POLYMERS

PRIORITY DOCUMENT

[0001] The present application claims priority from Australian Provisional Patent Application No. 2020901215 titled “METHODS FOR PROCESSING POLYSULFIDE POLYMERS” and filed on 17 April 2020, the content of which is hereby incorporated by reference in its entirety

TECHNICAL FIELD

[0002] The present disclosure relates generally to new polymeric materials and articles made therefrom More specifically the present disclosure relates to new polymeric materials and articles formed by processing polysulfide polymer containing materials.

BACKGROUND

[0003] Polysulfides are a class of chemical compounds containing chains of two or more sulfur atoms. Over the years, a number of high sulfur content polysulfide materials have been produced by reacting elemental sulfur with alkenes and polyenes such as styrene, terpenes, unsaturated triglycerides, and dicyclopentadiene. Recently, a process coined inverse vulcanization was introduced in which elemental sulfur is converted into polymers by ring-opening polymerization, followed by cross-linking with an unsaturated organic molecule such as a polyene. The resulting materials have high sulfur content (typically 50 to 90 % sulfur by mass) and display a range of useful properties that have given rise to their use in diverse applications including repairable materials, energy generation and storage, optical devices, and environmental remediation.

[0004] The present inventors have previously developed a number of high sulfur content polysulfide polymers through the copolymerization of triglycerides and sulfur. The products of the so-called “inverse vulcanization” contain 50 % sulfur by mass and have been evaluated for use as a sorbent for a range of metals and, for example, have been used in the removal of inorganic and alkylmercury compounds from water.

[0005] There is a need for new or improved methods for manipulating polysulfide polymers to produce new materials.

SUMMARY

[0006] Polymers made by inverse vulcanization have high sulfur content (typically 50 % by mass or higher). These polymers contain polysulfide groups (stretches of S-S bonds) that are reactive. The present disclosure arises from the inventors’ research on methods for manipulating these S-S bonds in particular, the inventors have shown that thermal manipulation and catalytic manipulation of S-S bonds is possible in a controlled manner and this gives rise to a range of novel processing methods and materials.

[0007] According to a first aspect, disclosed herein is a process for preparing a unitary polysulfide polymer containing article, the process comprising contacting a plurality of article subunits containing a polysulfide polymer with one another under reaction conditions to cause sulfur-sulfur exchange reactions to occur between article subunits to thereby form the unitary polysulfide polymer article.

[0008] In certain embodiments, the polysulfide polymer is a polymer that contains S-S bonds and has a total sulfur content of 20 to 90 wt%. In certain specific embodiments, the polysulfide polymer is formed by inverse vulcanisation of sulfur and an unsaturated organic compound or compounds.

[0009] In certain embodiments, the average length of the polysulfide groups in the polysulfide polymer is from about S₂ to about S₁₀, such as about S₂ to about S₄.

[0010] According to a second aspect, disclosed herein is a unitary polysulfide polymer containing article, the article being formed by sulfur-sulfur exchange reactions between article subunits containing a polysulfide polymer.

[0011] In certain embodiments, the conditions to cause sulfur-sulfur exchange reactions to occur comprise compression and heating. Thus, according to a third aspect, disclosed herein is a unitary polysulfide polymer article comprising a compression molded polysulfide polymer material.

[0012] According to a fourth aspect, disclosed herein is a process for preparing a compression molded unitary polysulfide polymer article, the process comprising: providing article subunits containing a polysulfide polymer; placing the article subunits of polysulfide polymer into a mold; and compressing and heating the article subunits in the mold under conditions to cause sulfur- sulfur exchange reactions to occur between the article subunits to thereby form a compression molded unitary polysulfide polymer article.

[0013] For the process of the fourth aspect, the article subunits containing a polysulfide polymer need to be compressible. Therefore, in certain embodiments, the polysulfide polymer is a rubber or gel-like polysulfide polymer.

[0014] In certain embodiments, the article subunits are in the form of particles containing the polysulfide polymer. [0015] In certain embodiments, the article subunits are compressed in the mold to a pressure of at least 10 MPa. In certain specific embodiments, the article subunits are compressed in the mold to a pressure of from about 10 MPa to about 40 MPa.

[0016] In certain embodiments, the article subunits are heated in the mold to a temperature of at least 90 °C. In certain specific embodiments, the article subunits are heated in the mold to a temperature of from about 90 °C to about 110 °C, such as about 100 °C.

[0017] In certain embodiments, the article subunits are compressed and heated in the mold for a time period of at least 10 minutes. In certain specific embodiments, the article subunits are compressed and heated in the mold for a time period of from about 10 minutes to about 60 minutes.

[0018] In certain embodiments, the process further comprises recovering the compression molded unitary polysulfide polymer article from the mold.

[0019] In certain other embodiments, the conditions to cause sulfur-sulfur exchange reactions to occur comprise treatment with a nucleophile catalyst. Thus, according to a fifth aspect, disclosed herein is a unitary polysulfide polymer article, the article being formed by chemically initiated sulfur-sulfur exchange reactions between article subunits containing a polysulfide polymer.

[0020] According to a sixth aspect, disclosed herein is a process for preparing a unitary polysulfide polymer article, the process comprising: providing article subunits each containing a polysulfide polymer; treating at least one surface of each article subunit with a nucleophile catalyst to form treated article subunits having catalyst treated surface(s); and contacting the catalyst treated surface(s) of the treated article subunits under conditions to cause sulfur-sulfur exchange reactions to occur between article subunits to thereby form the unitary polysulfide polymer article.

[0021] In certain embodiments of the sixth aspect, the nucleophile catalyst may be an amine or a phosphine. The amine may be selected from one or more of the group consisting of pyridine, triethyl amine, trimethyl amine, ammonia, hydroxyl amine, hydrazine, DABCO, nicotinates, tributyl amine, benzyl amine, imidazole and its derivatives and other aromatic and aliphatic amines. The phosphine may be selected from one or more of the group consisting of tributylphosphine, TCEP, triphenylphosphine and other nucleophilic phosphines.

[0022] When amines are used in the catalytic adhesion, they are most effective when the sulfur rank is >2. BRIEF DESCRIPTION OF THE FIGURES

[0023] Embodiments of the present disclosure will be discussed with reference to the accompanying figures wherein:

[0024] Figure 1 shows a schematic representation showing the formation of a polysulfide polymer (A), and the thermally induced sulfur-sulfur exchange reaction to form a unitary polysulfide polymer article (B);

[0025] Figure 2 shows details of a thermally induced reactive compression molding process of embodiments of the present disclosure (A), unitary compression molded polymer polysulfide articles formed at different pressures (B), unitary compression molded polymer polysulfide articles formed at different temperatures (C), and unitary compression molded polymer polysulfide articles formed at different reaction times (D);

[0026] Figure 3 shows photographs demonstrating the recycling of unitary compression molded polymer polysulfide articles (A), and formation of a unitary compression molded polymer polysulfide article from Fe loaded polysulfide polymer (B);

[0027] Figure 4 shows photographs of composites made by compression molding 50 to 70 wt% coconut coir and the polysulfide polymer;

[0028] Figure 5 shows a photograph of a side view of a composite made by compression molding 70 wt% coconut coir and 30 wt% polysulfide polymer;

[0029] Figure 6 shows photographs of composites made by compression molding 50 to 80 wt% recycled PVC and the polysulfide polymer;

[0030] Figure 7 shows a photograph of a side view of a composite made by compression molding 70 wt% recycled PVC + 30 wt% polysulfide polymer;

[0031] Figure 8 shows photographs of composites made by compression molding 70 to 80 wt% sand and the polysulfide polymer between two polysulfide polymer mats;

[0032] Figure 9 shows a photograph of a side view of a composite made by compression molding 70 wt% sand + 30 wt% polysulfide polymer between two polysulfide polymer mats;

[0033] Figure 10 shows photographs of composites made by compression molding 80 wt% urea and 20 wt% polysulfide polymer; [0034] Figure 11 shows a schematic diagram illustrating the compression molding of articles made by compression molding 50 wt% coconut coir and 50 wt% polysulfide polymer using polysulfide polymer particles between adjacent articles;

[0035] Figure 12 shows photographs of a stack of 50 wt% coconut coir and 50 wt% polysulfide polymer formed using the method shown in Figure 11 ;

[0036] Figure 13 shows a schematic representation showing the chemically induced sulfur-sulfur exchange reaction to form a unitary polysulfide polymer article;

[0037] Figure 14 shows photographs showing the joining of two polysulfide polymer containing article subunits using pyridine or tributylphosphme (a), the joining of two polysulfide polymer containing article subunits using pyridine or tributylphosphme and subsequent testing (b), the joining of multiple polysulfide polymer containing article subunits using pyridine (c), and formation of a unitary polysulfide polymer article from ground poly sulfide polymer articles using pyridine (d);

[0038] Figure 15 shows photographs showing the formation of polysulfide polymer articles;

[0039] Figure 16 shows photographs showing the joining of two polysulfide polymer containing article subunits using pyridine or tributylphosphine;

[0040] Figures 17A and 17B show plots of volume of pyridine v stress at failure for pyridine initiated unitary polysulfide polymer articles and tributylphosphine initiated unitary polysulfide polymer articles;

[0041] Figures 18A and 18B show plots of contact tune v stress at failure for pyridine initiated unitary polysulfide polymer articles (left) and tributylphosphine initiated unitary polysulfide polymer articles (right);

[0042] Figure 19 shows photographs of an apparatus for compressing polysulfide polymer article subunits for chemically induced sulfur-sulfur exchange reactions;

[0043] Figures 20A and 20B show plots of compression v stress at failure for pyridine initiated unitary polysulfide polymer articles and tributylphosphine initiated unitary polysulfide polymer articles;

[0044] Figure 21 shows photographs of the joining of two polysulfide polymer containing article subunits using pyridine or tributylphosphme and subsequent adhesion to metal plates for stress testing;

[0045] Figure 22 shows photographs of a shear force testing apparatus used to test shear forces on the article shown in Figure 21 ; [0046] Figure 23 shows photographs of a peel testing apparatus used to test peel forces on the article shown in Figure 21 ;

[0047] Figure 24 shows a photograph of positive and negative molds used to form polysulfide polymer bricks;

[0048] Figure 25 shows a photograph showing the joining of polysulfide polymer bricks using pyridine;

[0049] Figure 26 shows photographs of an apparatus used to form a unitary polysulfide polymer article from ground polysulfide polymer articles using pyridine as catalyst; and

[0050] Figure 27 shows a process for forming a unitary polysulfide polymer article from ground polysulfide polymer articles using pyridine as catalyst.

DESCRIPTION OF EMBODIMENTS

[0051] Unless otherwise defined, all terms used in the present disclosure, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art. By means of further guidance, term definitions are included to better appreciate the teaching of the present disclosure.

[0052] As used herein, the following terms have the following meanings:

[0053] “A”, “an”, and “the” as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, “an oxidant” refers to one or more than one oxidant.

[0054] “About” as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of +/-20 % or less, preferably +/-10 % or less, more preferably +/-5 % or less, even more preferably +/-1 % or less, and still more preferably +/- 0.1 % or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier “about” refers is itself also specifically disclosed.

[0055] “Comprise”, “comprising”, and “comprises” and “comprised of’ as used herein are synonymous with “include”, “including”, “includes” or “contain”, “containing”, “contains” and are inclusive or open- ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein. [0056] The expression “% by weight” (weight percent), here and throughout the description unless otherwise defined, refers to the relative weight of the respective component based on the overall weight of the formulation or element referred to.

[0057] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints, except where otherwise explicitly stated by disclaimer and the like.

[0058] As discussed, the present disclosure is concerned with polymers that contain polysulfide groups (stretches of S-S bonds) that are reactive and the inventors’ research into methods for manipulating these S-S bonds. In particular, thermal manipulation and catalytic manipulation of S-S bonds is possible in a controlled manner and this gives rise to a range of novel processing methods and materials.

[0059] The thermal and catalytic methods described herein allow one to form a unitary polysulfide polymer containing article from a plurality of subunits. This is shown schematically in Figure IB for a thermal process and in Figure 13 for a catalytic process. In each case, sulfur-sulfur exchange reactions occur at the interface between adjacent subunits and these sulfur-sulfur exchange reactions lead to the subunits being joined by one or more new sulfur-sulfur bonds. The subunits can be in any form and may, for example, be in the form of particles, or larger formed articles. In all cases, a plurality of subunits containing a polysulfide polymer are contacted with one another and then the thermally or catalytically initiated sulfur-sulfur exchange reaction is initiated. The reaction may take place between subunits of similar morphology (eg. particle - particle (see eg. Figures 1 to 3 and 27), or article - article (see eg. Figures 13 to 16, 19, 25) or it may take place between subunits of different morphology (eg particle - article (see eg. Figure 11)). The sulfur-sulfur exchange reactions between subunits then lead to the formation of the unitary polymer article.

[0060] The term “poly sulfide polymer” as used herein refers to a material that contains multiple sulfur atoms linked together through S-S bonds, and the sulfur chains are cross-linked through reaction with an unsaturated organic compound or compounds. The polysulfide polymer may be any polymer formed from reaction of sulfur with an unsaturated cross-linker. In certain embodiments, the polysulfide polymer is a polymer that contains S-S bonds and has a total sulfur content of 20-90 wt% In certain embodiments, the average length of the polysulfide groups in the polysulfide polymer is from about S₂ to about S₁₀, such as about S₂ to about S_4.

[0061] The polysulfide polymer can be formed using any suitable technique. Inverse vulcanization is one technique that can be used but it is also possible that polysulfide polymers with sulfur rank of 3 to 5 could be made using other techniques as well. With that in mind, it will be appreciated that the processing techniques described herein apply to any polysulfide polymer made by any suitable method [0062] Methods for producing polysulfide polymers from an unsaturated cross-linker are known in the art, for example as described in W. J . Chung et al. Nat. Chem. 2013, 5 :518-524, Lim et al. Angew.

Chem. Ini. Ed. 2015, 54: 3249-3258, Worthington et al. Chem. Eur. J , 2017, 23: 16219-16230, Worthington et al. Adv. Sustainable Syst ., 2018, 2 : 1800024, and Smith et al. Chem. Eur. J. 2019, 25: 10433-10440.

[0063] In certain embodiments, the polysulfide polymer is formed by inverse vulcanisation of sulfur and an unsaturated organic compound or compounds. In these embodiments, the polysulfide polymer may be formed using any of the methods disclosed in published International Patent Application No. WO 2017/181217, the details of which are hereby incorporated by reference. Briefly, in these methods a polysulfide polymer is formed by reacting a fatty acid composition comprising at least one unsaturated fatty acid or derivative thereof with sulfur, at a weight ratio between 9:1 and 1:9, under inverse vulcanisation conditions to produce a polymeric polysulfide wherein at least 50 % of the fatty acids or derivatives thereof in the fatty acid composition are unsaturated.

[0064] The fatty acid composition may be a glyceride composition. The glyceride composition may comprise either one or both of a triglyceride and a diglyceride in a substantially pure form. In certain embodiments, the glyceride composition comprises a mixture of either one or both of triglycerides and diglycerides. In certain embodiments either one or both of the triglyceride and the diglyceride comprise at least one fatty acid having 8 to 24 carbon atoms in the chain inclusive, including, but not limited to, a- linolenic acid, stearidonic acid, stearic acid, ricinoleic acid, dihydroxystearic acid, eicosapentaenoic acid, docosahexaenoic acid, linoleic acid, g-linolenic acid, dilhomo-y-linolenic acid, arachidonic acid, docosatetraenoic acid, palmitoleic acid, vaccenic acid, paullinic acid, oleic acid, elaidic acid, gondoic acid, erucic acid, nervonic acid or mead acid

[0065] In certain embodiments, the glyceride composition comprises at least one naturally derived oil or synthetic oil. In certain embodiments, the glyceride composition comprises or is derived from at least one oil of acai palm, avocado, brazil nut, canola, castor, corn, cottonseed, grape seed, hazelnut, linseed, mustard, peanut, olive, rice bran, safflower, soybean or sunflower.

[0066] Advantageously, the glyceride composition may be a used natural or synthetic oil composition, such as an oil that has previously been used for the production of foodstuffs. This then provides a relatively cheap and/or environmentally useful glyceride composition.

[0067] In certain other embodiments, the fatty acid composition is a fatty acid ester composition. The fatty acid ester composition may comprise esters of any one or more unsaturated fatty acids. The ester may be an alkyl ester, such as a methyl ester, an ethyl ester or a propyl ester. The fatty acid esters may be formed by esterification of fatty acids or by transesterification of a glyceride composition or a fatty acid derivative, such as a fatty acid amide. In certain embodiments the fatty acid has 8 to 24 carbon atoms in the chain inclusive. The fatty acid may be selected from one or more of the group, including, but not limited to, a-linolenic acid, stearidonic acid, stearic acid, ricinoleic acid, dihydroxystearic acid, eicosapentaenoic acid, docosahexaenoic acid, linoleic acid, g-linolenic acid, dihomo-y-linolenic acid, arachidonic acid, docosatetraenoic acid, palmitoleic acid, vaccenic acid, paullinic acid, oleic acid, elaidic acid, gondoic acid, erucic acid, nervonic acid or mead acid

[0068] The fatty acid ester may be derived from a natural oil or a synthetic oil. In certain embodiments, the fatty acid ester is derived from at least one oil of acai palm, avocado, brazil nut, canola, castor, corn, cottonseed, grape seed, hazelnut, linseed, mustard, peanut, olive, rice bran, safflower, soybean or sunflower.

[0069] In certain embodiments, the weight ratio of the fatty acid composition and the sulfur is between 9: 1 and 1:9. For example, 8:1, 7:1, 6: 1, 5:1, 5:2, 2:1, 3:2, 1:1, 2:3, 1:2, 2:5, 1:5, 1:6, 1:7 or 1:8. Accordingly, in certain embodiments where the fatty acid composition is an oil, such as canola oil, the ratio of canola oil to sulfur could be 1: 1. In certain embodiments, the weight ratio of the glyceride composition and the sulphur may be modified as appropriate.

[0070] In certain embodiments, the sulfur comprises elemental sulfur. In certain embodiments, the sulfur comprises at least one allotrope of sulphur such as S5, S6, S7 or S8. In certain embodiments, S8 is at least one of alpha-sulfur (commonly called sulfur flowers), beta-sulfur (or crystalline sulfur) or gamma- sulfur (also called mother of pearl sulfur). In certain embodiments, the sulfur comprises any poly-S reagent, intermediate, or product generated from sulphide (such as sodium sulphide), sodium chloride or hydrogen sulphide.

[0071] The polysulfide polymer is a solid. In certain embodiments, the polysulfide polymer is a rubber. In certain embodiments, the polysulfide polymer is elastic and malleable at temperatures up to approximately 150 °C, whereupon the poly sulfide polymer starts to decompose. In certain embodiments, the polysulfide polymer starts to decompose at temperatures above approximately 150, 155, 160, 165,

170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245 or 250 °C. The temperature at which the polysulfide polymer starts to decompose may be increased by, for example, increasing the sulfur content.

[0072] The polysulfide polymer is formed by reacting the fatty acid composition with sulfur under inverse vulcanisation conditions. Inverse vulcanisation involves adding the fatty acid composition to relatively high weight percentages of liquid sulfur. This is in contrast to classic vulcanisation which involves adding relatively low weight percentages of sulfur to a hot fatty acid composition. [0073] It will be evident from the foregoing that also disclosed herein is a unitary polysulfide polymer containing article, the article being formed by sulfur-sulfur exchange reactions between subunits containing a polysulfide polymer.

[0074] As discussed earlier, the sulfur-sulfur exchange reactions occurring at the interface between adjacent subunits may be thermally induced. In these embodiments, the conditions to cause sulfur- sulfur exchange reactions to occur comprise compression and heating. This then provides a polysulfide polymer article comprising a compression molded polysulfide polymer material

[0075] Thus, disclosed herein is a process for preparing a compression molded polysulfide polymer article. The process comprises providing particles comprising a polysulfide polymer. The particles of polysulfide polymer are placed into a mold and are then compressed and heated in the mold under conditions to cause interparticle sulfur-sulfur exchange reactions to occur to thereby form a compression molded polysulfide polymer article.

[0076] For the thermally induced process, the particles comprising a polysulfide polymer need to be compressible. Therefore, in certain embodiments, the polysulfide polymer is a rubber or gel-like polysulfide polymer with a compression modulus low enough for the polymer substance to be compressed when force is applied.

[0077] The polysulfide polymer particles are preferably compressed in the mold to a pressure of at least 10 MPa. In certain embodiments, the polysulfide polymer particles are compressed in the mold to a pressure of from about 10 MPa to about 40 MPa, such as about 10 MPa, about 11 MPa, about 12 MPa, about 13 MPa, about 14 MPa, about 15 MPa, about 16 MPa, about 17 MPa, about 18 MPa, about 19 MPa, about 20 MPa, about 21 MPa, about 22 MPa, about 23 MPa, about 24 MPa, about 25 MPa, about 26 MPa, about 27 MPa, about 28 MPa, about 29 MPa, about 30 MPa, about 31 MPa, about 32 MPa, about 33 MPa, about 34 MPa, about 35 MPa, about 36 MPa, about 37 MPa, about 38 MPa, about 39 MPa or about 40 MPa.

[0078] Preferably, the polysulfide polymer particles are heated in the mold to a temperature of at least 90 °C. In certain embodiments, the polysulfide polymer particles are heated in the mold to a temperature of from about 90 °C to about 110 °C, such as about 90 °C, about 91 °C, about 92 °C, about 93 °C, about 94 °C, about 95 °C, about 96 °C, about 97 °C, about 98 °C, about 99 °C, about 100 °C, about 101 °C, about 102 °C, about 103 °C, about 104 °C, about 105 °C, about 106 °C, about 107 °C, about 108 °C, about 109 °C, or about 110 °C. In certain specific embodiments, the temperature is about 100 °C.

[0079] Preferably, the polysulfide polymer particles are compressed and heated in the mold for a time period of at least 10 minutes. In certain specific embodiments, the polysulfide polymer particles are compressed and heated in the mold for a time period of from about 10 minutes to about 60 minutes, such as about 10 minutes, about 11 minutes, about 12 minutes, about 13 minutes, about 14 minutes, about 15 minutes, about 16 minutes, about 17 minutes, about 18 minutes, about 19 minutes, about 20 minutes, about 21 minutes, about 22 minutes, about 23 minutes, about 24 minutes, about 25 minutes, about 26 minutes, about 27 minutes, about 28 minutes, about 29 minutes, about 30 minutes, about 31 minutes, about 32 minutes, about 33 minutes, about 34 minutes, about 35 minutes, about 36 minutes, about 37 minutes, about 38 minutes, about 39 minutes, about 40 minutes, about 41 minutes, about 42 minutes, about 43 minutes, about 44 minutes, about 45 minutes, about 46 minutes, about 47 minutes, about 48 minutes, about 49 minutes, about 50 minutes, about 51 minutes, about 52 minutes, about 53 minutes, about 54 minutes, about 55 minutes, about 56 minutes, about 57 minutes, about 58 minutes, about 59 minutes or about 60 minutes.

[0080] Following compression molding at the desired pressure, temperature and time, the compression molded polysulfide polymer article is recovered from the mold.

[0081] The compression molding process may be used to form a range of composite materials or articles by incorporating any one or more of a wide range of organic or inorganic additives with the article subunits in the compression molding process. For example, organic materials such as coconut coir, recycled PVC or other plastic, wool, hair, wood chips or shavings, mulch, plant waste, and/or inorganic materials such as sand, fertiliser nutrients, gravel, silica particles, fiberglass, glass powder, limestone, fly ash, carbon (activated carbon, charcoal, graphene, graphite, carbon fibre, nanotubes, etc), quarry dust, crushed cement or concrete or bricks, or slag can be incorporated to form composite materials. This may be used to provide new or desirable properties to the composite material.

[0082] Advantageously, the processes described herein allow for the incorporation of organic or inorganic additives into the composite materials at relatively low temperatures For example, fertiliser nutrients have previously been incorporated in polysulfide polymers by adding NPK nutrients into the reaction mixture that is used to form the polysulfide polymer and this reaction reaches temperatures of around 180 °C (see Org. Biomol. Chem. 2019, 17, 1929-1936). However, for some nutrients, such as urea, this method is not particularly suitable because urea melts at a lower temperature and is not compatible with the polymerisation. In contrast, using the processes described herein it is possible to incorporate nutrients such as urea into the composite materials which are then suitable for use as a fertiliser This then provides a new method for making this slow release fertiliser (see Figure 11)

[0083] The starting article subunits may contain polysulfide polymer that is loaded with another agent, such as a metal loaded polysulfide polymer. This then allows for polysulfide polymer that has previously been used as a sorbent to be used as a starting material in the formation of unitary poly sulfide polymer articles including new composite materials. [0084] As discussed earlier, the sulfur-sulfur exchange reactions occurring at the interface between adjacent subunits may be chemically initiated by a nucleophile catalyst. This then provides a poly sulfide polymer article that has been formed by chemically initiated mterparticle sulfur-sulfur exchange reactions between subunits containing a polysulfide polymer.

[0085] Thus, disclosed herein is a process for preparing a poly sulfide polymer article. The process comprises providing a plurality of article subunits each containing a polysulfide polymer and treating at least one surface of each article subunit with a nucleophile catalyst to form treated particles having catalyst treated surface(s). The catalyst treated surface(s) of the treated particles are then contacted with one another under conditions to cause interparticle sulfur-sulfur exchange reactions to occur to thereby form a unitary polysulfide polymer article from the article subunits.

[0086] A range of nucleophile catalysts are suitable for use in the chemically initiated sulfur-sulfur exchange reaction. For example, the nucleophile catalyst may be an amine or a phosphine. The amine may be selected from one or more of the group consisting of pyridine, triethyl amine, trimethyl amine, ammonia, hydroxyl amine, hydrazine DABCO, nicotinates, tributyl amine, benzyl amine, imidazole and its derivatives and other aromatic and aliphatic amines The phosphine may be selected from one or more of the group consisting of tributylphosphine, TCEP, triphenylphosphine and other nucleophilic phosphines.

[0087] When amines are used in the catalytic sulfur-sulfur exchange reaction, they are most effective when the sulfur rank is >2.

[0088] Advantageously, when the nucleophile catalyst is a volatile amine it can catalyse the sulfur- sulfur exchange reactions between article subunits and then evaporate. In this way the catalyst is “traceless” and does not remain in the polymer.

EXAMPLES

[0089] Example 1 - Reactive compression molding of polysulfide polymers

[0090] The concept of reactive compression molding is illustrated in Figure 1. In this process, a polysulfide copolymer made from canola oil and sulfur is a compressible rubber. When heated, this polymer does not melt. But, the application of thermal energy results in the breaking and reforming of the S-S bonds in the backbone of the polymer. If the polymer pieces are heated without compression, the polymer pieces do not bind together. However, if the polymer is heated (80 to 120 °C) and compressed (20 to 40 MPa), then the polymer pieces are forced together and the S-S bonds undergo exchange reactions. This allows the conversion of the powdered polymer into a polymer mat. This reactive processing allows the synthesis of composite materials, polymer recycling, and polymer repurposing. It is important to note that the temperature at which the reactive compression molding is carried out (~ i 00 °C) is far lower than the temperature required to make the original polymer (-180 °C). This means that composites can be made using fillers that do not tolerate the temperature used in the polymerization to form the original polymer.

[0091] A polysulfide made from canola oil and sulfur was prepared as previously described (Chem.

Eur. J. 2017, 23, 16219-16230 and Mercury Adsorbent Material and Uses Thereof. Patent No. WO 2017181217. Priority Application AU 2016-901470, April 202016). This polymer can vary in the composition of sulfur, with typical values ranging from 30 wt% to 70 wt% sulfur.

[0092] To carry out the reactive compression molding, a 10 x 10 cm poly(tetrafluoroethylene) (PTFE) sheet was placed in a stainless steel mold. Next, 5.0 g of the powdered polysulfide polymer was placed on the PTFE sheet and a second PTFE was placed on top of the polymer before the mold was sealed. The mold was placed in the heated hydraulic press and incubated across a range of temperatures, times and pressures.

[0093] A durable rubber mat was formed when the temperature was 90 to 110 °C, with 100 °C as the optimal temperature. Pressure was required to force the reactive faces of the powder together (10 to 40 MPa) and 40 MPa provided the most uniformity. A minimum of 10 minutes processing time was required at these temperatures and pressures. Representative outcomes are shown in Figure 2

[0094] Example 2 - Polymer recycling

[0095] A formed mat was prepared as described in Example 1. Next, the mat was milled into pieces <1 cm² and then resubjected to the reactive compression molding A smooth mat was reformed indicating this technique can be used for polymer recycling (Figure 3 A).

[0096] Example 3 - Polymer repurposing

[0097] A powdered polysulfide polymer was used to remove iron from water as previously described (RSC Advances, 2018, 8, 1232-1236). The polymer-iron complex was repurposed into a mat using the compression molding process described in Example 1 (Figure 3B). This illustrates how the polysulfide polymer can be repurposed into a new material after binding to metals. This process can be repeated with additional pristine polymer as a method to lock metals onto the polymer.

[0098] This application is useful for immobilising pollutants trapped on polysulfide polymers, composites containing polysulfide polymers, or polysulfide polymers blended with other sorbents such as activated carbon and other porous materials. The polymers can bind various pollutants including, but not limited to, metals, hydrocarbons, and organic (micro)pollutants (pesticides, herbicides, PCBs, PFASs, TCE, etc). Mixing the polymer-pollution sorbent with fresh polymer and then converting the entire mixture into a polymer block provides a method to lock in the pollution and prevent leaching during transport and storage. The polymer is resistant to water and acid, so it is durable.

[0099] Example 4 - Composite synthesis

[00100] The polymer can be physically mixed or blended with a variety of fillers and then subjected to reaction compression molding to make new composites. The fillers include, but are not limited to, sand, gravel, silica particles, fiberglass, glass powder, limestone, fly ash, carbon (activated carbon, charcoal, graphene, graphite, carbon fibre, nanotubes, etc), quarry dust, crushed cement or concrete or bricks, slag, fertiliser nutrients and other inorganic materials, recycled plant and wood fibres, wood chips and shavings, mulch, plant waste, agriculture waste such as husks or stubble, recycled rubber and plastics, synthetic fibres or recycled synthetic fibres, animal fibres such as wool or hair, or organic fertiliser nutrients. The ratio of polymer and filler can vary, but typically the filler is used at 50 to 90 wt% of the entire composite.

[00101] Representative composites are shown below, made by blending the polysulfide polymer referred to in Example 1 with the filler and then processing via reactive compression molding (100 °C, 40 MPa, 20 minutes). Note that all fillers make the composite flat and rigid, whereas the polymer mat alone with no filler is soft and flexible.

[00102] Composites made from 50 to 70 wt% coconut coir and the polysulfide polymer are shown in Figure 4. A side view of a composite made from 70 wt% coconut coir + 30 wt% polysulfide polymer is shown in Figure 5.

[00103] Composites made from 50 to 80 wt% recycled PVC and the polysulfide polymer are shown in Figure 6. A side view of the composite made from 70 wt% recycled PVC + 30 wt% polysulfide polymer is shown in Figure 7.

[00104] Composites made from 70 to 80 wt% sand and the polysulfide polymer are shown in Figure 8. The sand and polysulfide mixture was processed between two separate polysulfide polymer mats. A side view of the composite made from 70 wt% sand + 30 wt% polysulfide polymer is shown in Figure 9.

[00105] A composite made from 80 wt% urea and 20 wt% polysulfide polymer is shown in Figure 10.

[00106] The polymer mats or composites can be assembled in an additive fashion. In this way, the individual layers react with each other and form a single monolithic polymer or composite block. This is illustrated in Figure 11 for composite mats made from 50 wt% coconut coir and 50 wt% polysulfide polymer. A similar process was also used in the sand composite in Figure 9. The extra polymer added in between each layer acts as chemical mortar to join the layers together chemically (Figure 12).

[00107] The additive assembly may have utility in preparing new laminate material, composite wood sheets, insulation, or other construction materials.

[00108] The material properties of the composite are different from the base polymer. For instance, the sand composites are very hard, with a compression modulus of 12 MPa, while the mat formed from the polymer only had a measured compression modulus of 7 MPa The composite materials can be tuned in their elasticity, compression modulus, tensile strength, and flexural modulus.

[00109] Example 5 - Polymer adhesion induced by a catalyst at room temperature

[00110] As illustrated in Figure 13, a nucleophile can break the S-S bonds in the polysulfide polymer and lead to catalytic S-S exchange (also called metathesis). This reaction results in converting two polymer pieces into one polymer block. Unlike the reactive compression molding discussed above, the catalytic process shown below occurs at room temperature. This is the first reactive processing method reported for polysulfide polymers made by inverse vulcanisation that occurs at room temperature.

[00111] Applications enabled by catalytic S-S exchange on polysulfide polymers include polymer repair, latent adhesives, additive assembly of polymer components, and recycling, as shown in Figure 14.

[00112] A terpolymer was prepared as previously described (Chem. Eur. J. 2019, 25, 10433-10440). Sulfur (5.0 g) was heated to 170 °C for 2.5 minutes before a pre-heated mixture (170 °C) of dicyclopentadiene and canola oil (2.5 g each) was added to the sulfur. The mixture was stirred vigorously at 170 °C for 13 minutes and the resulting black prepolymer was then poured into a silicone mold (Figure 15). The polymer was cured in the mold at 130 °C for 24 hours.

[00113] The tensile strength of the polymers was tested using a dynamic mechanical analyser (TA Instruments Q800). The film tension clamp was used, with polymer pieces clamped at the wider clamping section. Care was taken to ensure that the clamp was not in contact with the gage section as the strain caused by the clamp can lead to premature failure of the polymer. The DMA controlled force module was used. The force was ramped at a rate of 0.2 N/min with a maximum force of 18 N Flowever, the force never reached this point as the polymer would fail at lower force. The tensile modulus was 2.11 ± 0.09 MPa. The maximum tensile strength was determined by the stress at the yield point. The average tensile strength was 0.182 ± 0.001 MPa.

[00114] The dog bone polymer pieces were cut the entire way through the centre of the gage section using a scalpel to produce two halves (Figure 16). A catalyst comprising either pyridine or tributylphosphine was then added by pipette to the cut surface The two polymer pieces were then returned to the mold so that the cut interfaces were in passive contact (no pressure was applied to force the pieces together). The volumes of catalyst tested were 1 μL, 5 μL, 10 μL and 15 μL of both pyridine and tributylphosphine. Each volume was tested in triplicate. These volumes correspond to 12.4 μmol,

62. l μmol, 124 pmol and 186 pmol for pyridine and 4.05 pmol, 20.3 pmol, 40.5 pmol and 60.8 μ ol for tributylphosphine. After 24 hours, the pieces were removed from the mold and all pieces showed adhesion. The full process is shown in Figure 16.

[00115] The strength of adhesion at the repaired interface was tested using dynamic mechanical analysis. The film tension DMA clamp was used with the DMA controlled force module. Care was taken to ensure that the clamp was not in contact with the gage section as the strain caused by the clamp can lead to premature failure of the polymer. The force was ramped at a rate of 0.2 N/min with a maximum force of 18 N. The pieces failed at the repaired interface. Therefore, the strain at failure indicates the strength of adhesion caused by the tributylphosphine or pyridine induced reaction Three replicas of each of the volumes of pyridine or tributylphosphine were tested as well as three replicas of undamaged polymer pieces as controls. A control of the cut polymer with no catalyst was also tested but showed no adhesion and could therefore not be tested using DMA. The results are shown in Figure 17 and Table 1.

[00116] Table 1

[00117] To gain an understanding into the time required to repair the polymer with pyridine and tributylphosphine, the adhesion strength was determined for several different reaction times. Dog bone shaped polymer pieces were cut through the centre of the gage section and repaired as described above using the volume of pyridine and tributylphosphine that corresponded to the greatest adhesion strength. This volume was 10 μL. of pyridine and 1 μL of tributylphosphine, as determined in the previous experiment. Three replicas were prepared and left to react without pressure for time periods of 1, 2, 4, 6, 12 and 24 hours for both pyridine and tributylphosphine. After the reaction had been left for the designated amount of time, the repaired polymer pieces were tested for tensile strength using dynamic mechanical analysis with the same method as described earlier.

[00118] The samples that were repaired with pyridine reached maximum adhesion strength after two hours which then remained constant up to 24 hours. The one hour sample had approximately half the adhesion strength of the 24 hour sample, indicating that it takes between one and two hours for the pyridine induced reaction to reach a maximum adhesion strength. The samples that were repaired with tributylphosphine reached maximum adhesion strength after one hour. The adhesion strength then remained relatively constant for all other time periods, up to 24 hours, as shown in Figure 18. This indicates that the reaction with tributylphosphine is faster than that of pyridine, reaching maximum adhesion strength after one hour. Note that all but the one hour sample of pyridine showed a stronger adhesion than tributylphosphine.

[00119] For pyridine or tributylphosphine to induce polymer repair, the polymer interfaces must be directly in contact. By applying pressure between the interfaces, contact between the polymer interfaces throughout the reaction could be ensured. The polymer pieces were compressed with a 3D printed apparatus which could apply controlled and consistent compression to twelve dog bone shaped polymer pieces. The pieces were clamped together using four 50 mm C clamps. This caused the pieces to be compressed to the width of the indentation while maintaining their shape. Several indentation thicknesses were tested. Indentation thicknesses of 10 %, 20 %, 30 %, 40 % and 50 % were produced but damage to the polymer became evident with compression greater than 30 %. A compression of 10 % corresponds to a reduction of 10 % of the original thickness of the polymer. The indentations for the 10 %, 20 %, 30 %, 40 % and 50 % apparatus corresponded to depths of 1.8 mm, 1.6 mm, 1.4 mm, 1.2 mm and 1 mm respectively. The 3D printed apparatus is shown in Figure 19.

[00120] The volumes of pyridine and tributylphosphine which corresponded to the greatest adhesion strength were selected for use in the compression tests. For pyridine, it was 10 μL and for tributylphosphine, it was 1 μL. The polymer pieces were cut with a scalpel in the centre of the gage section as with earlier tests. They were then placed in the compression mold and the pyridine and tributylphosphine was applied to the cut interface using a micropipette Several controls were also included which were compressed but were not cut and others that were cut but had no pyridine or tributylphosphine applied. The top 3D printed piece was then placed on top of the polymers and secured in place using four 50 mm C clamps. The C clamps were tightened until the top piece was flat against the piece with the indentations. The polymer was then left for 24 hours under compression. After 24 hours, the repaired pieces were removed from the indentations and tested for tensile strength using a dynamic mechanical analyzer with the same method as earlier tests. All controls which had no pyridine or tributylphosphine applied showed no adhesion, while the undamaged control samples showed no decrease in tensile strength for compression of less than 30 %. The strain at failure was used as a measure of the adhesion strength of the repaired pieces. The results are shown in Figure 20 and Table 2. The repair for pyridine was increased to 73 % of the strain observed in the control dog bone pieces. For tributylphosphine, not as much improvement was observed. It appears that pyridine, which is less reactive than tributylphosphine, requires more time and compression to ensure efficient contact and reaction time at the interface of the damaged polymer.

[00121] Table 2

[00122] Example 6 - Use of the polysulfide polymer as a latent adhesive

[00123] The polymer was synthesized as before, with curing in a mold that provided a shape with two parallel square interfaces, one larger than the other. The smaller of the two surfaces had a side length of 40 mm for a total surface area of 1600 mm². The larger surface had a side length of approximately 45 mm for a total surface area of 2025 cm². This corresponds to a 200-fold increase in surface area over the dog bone shaped polymers which had a reactive surface of 2 mm x 4 mm. The pieces had a width of approximately 5 mm. The 40 mm x 40 mm surface area was used for the reactive interface.

[00124] Next, six 150 mm x 50 mm x 3 mm steel plates were obtained and four holes were then drilled into the corners of each piece. The centre of the holes were placed 15 mm from both sides in each corner of the metal plates with a diameter of 10 mm. A hammer drill was used to make each of the holes using a 3 mm drill bit as a guide, followed by a 10 mm drill bit to expand the hole to the desired size. A 50 mm x 50 mm area in the middle of one side of each plate was lightly ground using a hand grinder to roughen the surface. The larger square surface of the polymer pieces were glued to the roughened area of the steel plates using epoxy glue. A small amount of the epoxy was mixed and applied to the roughened area of the steel plate. The larger surface of a polymer piece was then placed on the epoxy glue and left for two hours. A ceramic tile was placed on the top of the polymer piece and clamped to the metal plate to ensure good contact between the polymer and the metal plate. This was repeated for two steel plates with two separate polymer pieces.

[00125] The catalysts were then placed on the smaller exposed surface of the polymer using a micropipette. 200 μL of tributylphosphme or pyridine was used because this volume covered the 1600 mm² polymer interface without overflowing. After the addition of the catalyst to the polymer surface, another metal plate with attached polymer was placed on top such that the polymer surfaces were aligned, and the metal plates were positioned perpendicular to each other The polymer was then left for 24 hours to react before shear and peel tests were performed. Images of the polymer pieces and the metal plates are shown in Figure 21.

[00126] Shear force test

[00127] The shear force test was designed to pull each metal plate in opposite directions directly parallel to the adhered surface of the polymers. This was achieved by placing an 8 mm metal rod through each of the holes in one the metal plates. Nuts were used on both sides of the holes to prevent the plates from moving. An 8 mm steel quick connect chain link was then added to the top two holes of the other metal plate. A 1 m long, 5 mm thick steel chain was then hooked onto the quick connect chain link on one side, passed through a weight then hooked to the other quick connect chain link. The chain was doubled over to increase strength and decrease the total length to 50 cm. The weight was held by the adhesion for 30 seconds before removal. After which, the weight was removed and increased in mass. Intervals of 2.5 kg were used with a starting weight of 5 kg. The weight of the chain, two quick comiect chain links and the steel plate was 739.3 g combined which was added to the mass of the weights to give the total weight.

The greatest weight which was held for 30 seconds without failure was recorded as the maximum adhesion strength in this in-house test. After each test, the polymer and epoxy was removed from the metal using a handheld grinder. The experimental set up and tabulated data for the shear tests can be seen in Figure 22 and Table 3, respectively.

[00128] Table 3

[00129] Peel test

[00130] The peel test was designed to test the force required to pull the polymer pieces apart with a force directed in the normal direction away from the reacted surface. The same metal plates were used and the reactions were performed in the same way as the shear test A heavy retort stand was equipped with a bar which had a flattened steel section on the end. This flattened section had a width and length of 150 mm and a thickness of 3 mm. It had two 10 mm x 3 mm removed sections which ran parallel with the outer edges of the flattened section. The removed sections were located 22.5 mm from the outer edges of the flat section and were separated by 45 mm on the inner side.

[00131] Four 8 mm steel quick connect chain links were hooked through each of the holes in both metal plates. A 1 m long, 5 mm thick steel chain was used to hold one of the metal plates with the attached polymer level by hooking the chain over the bar attached to the retort stand. Care was taken to ensure that the metal plate was level by using the same number of chain links on both sides of the metal plate, with any slack taken up by wrapping the chain around the center part of the flattened steel bar. Another chain was hooked onto the quick connect chain links on one side of the other metal plate and passed through a weight before being hooked to the quick connect chain links on the other side Again, the chain was doubled up to increase strength and shorten the length. The weight was left for 30 seconds and if failure did not occur in this time, the weight was increased by 1 .25 kg. An initial weight of 2.5 kg was used. The weight of four quick connect chain links, the chain and the metal plate was 878.2 g. This was added to the mass of the weight to give the total mass. The testing apparatus and results are shown in Figure 23 and Table 4.

[00132] Table 4

[00133] Example 7 - Polymer assembly and additive manufacturing

[00134] The use of pyridine induced adhesion for polymer assembly was demonstrated by producing a wall of polymer bricks that were bound together using a pyridine as the “chemical mortar” A mold negative was 3D printed. The mold negative consisted of 10 rows of seven bricks. Six bricks in each row had dimensions of 10 mm x 10 mm x 16 mm while one brick in every row was made to be half the length, giving dimensions of 10 mm x 10 mm x 8 mm. This allowed the bricks to be overlapped like conventional brick laying techniques to increase strength and give a classic brick aesthetic. Each brick was separated by 5 mm and each row was separated by 5 mm. A wall was made that extended around the outside of the grid of bricks with a thickness of 3 mm and a height of 5 mm above the top of the bricks (15 mm total). Liquid silicone was mixed and poured into the mold negative up to the top of this wall and left for 2 hours at room temperature to cure. The mold negative and final mold is shown in Figure 24.

[00135] The polymer bricks were prepared using the same method as other experiments and maintained the same monomer ratio of 50 % sulfur, 35 % canola oil and 15 % DCPD. One 10 g batch could produce four full sized bricks and one half-brick After some experimentation, it was found that the optimum volume of pyridine to induce the adhesion of the polymer bricks was 1 μL/4 mm² For the 10 mm x 10 mm side of the polymer, this corresponded to 25 μL while for the larger 10 mm x 16 mm side of the polymer this corresponded to 40 μL of pyridine. The bottom layer of the wall was prepared first by applying 25 μL to the 10 mm x 10 mm side of a polymer brick and placing it in contact with the 10 mm x 10 mm side of another polymer brick. This was repeated for every brick on the bottom layer. Between layers, the wall was left for 30 minutes such that some adhesion had occurred before continuing to the next layer. For subsequent layers, 40 μL of pyridine was placed on the top of the previous layer for the 10 mm x 16 mm face and 25 μL of pyridine was applied to the 10 mm x 10 mm face of each brick. After all layers had been applied, the wall was left for 24 hours to ensure full adhesion of bricks (Figure 25). After this point, the wall could be picked up from any brick and remain intact.

[00136] Example 8 - Polymer recycling and reforming using a pyridine catalyst

[00137] Pyridine was used as a catalyst to recycle and reform the polymer. Dog bone shaped polymer pieces were cut with a scalpel into small pieces before being ground in a mortar and pestle. The ground polymer powder was passed through a 1 mm sieve. Any pieces which were too large to fit through the sieve were ground again until all particles were able to pass through the sieve 10 g of the ground polymer was weighed into a 100 mL beaker. This corresponds to approximately 8 dog bone pieces. 5 mL of pyridine was added to the polymer in 1 mL portions. After every addition of pyridine, the polymer was stirred with a small spatula for approximately 30 seconds. An 8.5 cm square press consisting of three parts, as shown below, was prepared in advance by fitting a Teflon sheet on the base piece The Teflon sheet is to prevent the polymer from sticking to the metal press. The outer piece was then placed around the base piece and the Teflon sheet. The pyridine-coated polymer was transferred to the Teflon sheet and distributed evenly using the same spatula. Another Teflon sheet was placed on top of the polymer and the top piece of the press was fitted into the outer piece. The polymer was then compressed to 40 MPa for 30 minutes at room temperature. After compression, the polymer maintained the shape of the press, forming a flexible sheet. A graphic showing the full procedure can be seen in Figures 26 and 27.

[00138] Throughout the specification and the claims that follow, unless the context requires otherwise, the words “comprise” and “include” and variations such as “comprising” and “including” will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

[00139] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

[00140] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.

Claims

1. A process for preparing a unitary polysulfide polymer containing article, the process comprising contacting a plurality of article subunits containing a polysulfide polymer with one another under reaction conditions to cause sulfur-sulfur exchange reactions to occur between article subunits to thereby form the unitary polysulfide polymer article.

2. The process of claim 1 , wherein the polysulfide polymer is a polymer that contains S-S bonds and has a total sulfur content of 20 to 90 wt%.

3. The process of either claim 1 or claim 2, wherein the polysulfide polymer is formed by inverse vulcanisation of sulfur and an unsaturated organic compound or compounds.

4. The process of claim 3, wherein the polysulfide polymer is formed by inverse vulcanisation of sulfur and canola oil.

5. The process of any one of claims 1 to 4, wherein the average length of the polysulfide groups in the polysulfide polymer is from about S₂ to about S₁₀.

6. The process of claim 5, wherein the average length of the poly sulfide groups in the polysulfide polymer is from about S₂ to about S_4.

7. A unitary polysulfide polymer containing article, the article being formed by sulfur-sulfur exchange reactions between article subunits containing a polysulfide polymer.

8. A process for preparing a compression molded unitary polysulfide polymer article, the process comprising: providing article subunits containing a polysulfide polymer; placing the article subunits of polysulfide polymer into a mold; and compressing and heating the article subunits in the mold under conditions to cause sulfur-sulfur exchange reactions to occur between article subunits to thereby form a compression molded unitary poly sulfide polymer article.

9. The process of claim 8, wherein the article subunits comprising a poly sulfide polymer are compressible.

10. The process of any one of claims 8 or 9, wherein, the article subunits are in the form of particles containing the polysulfide polymer.

11. The process of any one of claims 8 to 10, wherein the article subunits are compressed in the mold to a pressure of at least 10 MPa.

12. The process of claim 11, wherein the article subunits are compressed in the mold to a pressure of from about 10 MPa to about 40 MPa.

13. The process of any one of claims 8 to 12, wherein the article subunits are heated in the mold to a temperature of at least 90 °C.

14. The process of claim 13, wherein the article subunits are heated in the mold to a temperature of from about 90 °C to about 110 °C.

15. The process of claim 13, wherein the article subunits are heated in the mold to a temperature of about 100 °C.

16. The process of any one of claims 8 to 15, wherein the article subunits are compressed and heated in the mold for a time period of at least 10 minutes.

17. The process of claim 16, wherein the article subunits are compressed and heated in the mold for a time period of from about 10 minutes to about 60 minutes.

18. The process of any one of claims 8 to 17, wherein the process further comprises recovering the compression molded unitary polysulfide polymer article from the mold.

19. A unitary poly sulfide polymer article comprising a compression molded poly sulfide polymer material.

20. A process for preparing a unitary polysulfide polymer article, the process comprising: providing article subunits each containing a polysulfide polymer; treating at least one surface of each article subunit with a nucleophile catalyst to form treated article subunits having catalyst treated surface(s); and contacting the catalyst treated surface(s) of the treated article subunits under conditions to cause sulfur-sulfur exchange reactions to occur between article subunits to thereby form the unitary polysulfide polymer article

21. The process of claim 20, wherein the nucleophile catalyst is an amine or a phosphine.

22. The process of claim 21, wherein the amine is selected from one or more of the group consisting of pyridine, triethyl amine, trimethyl amine, ammonia, hydroxyl amine, hydrazine, DABCO, nicotinates, tributyl amine, benzyl amine, imidazole and its derivatives and other aromatic and aliphatic amines.

23. The process of claim 21, wherein the amine is pyridine.

24. The process of claim 21, wherein the amine is a volatile amine that evaporates after catalysing the sulfur-sulfur exchange reactions between article subunits.

25. The process of any one of claims 22 to 24, wherein the sulfur rank of the polysulfide polymer is greater than 2.

26. The process of claim 21 , wherein the phosphine is selected from one or more of the group consisting of tributylphosphine, TCEP, and triphenylphosphine.

27. The process of claim 21, wherein the phosphine is tributylphosphine.

28. A unitary polysulfide polymer article, the article being formed by chemically initiated sulfur- sulfur exchange reactions between article subunits containing a polysulfide polymer.