WO2008010823A2

WO2008010823A2 - Thermoplastic based composites

Info

Publication number: WO2008010823A2
Application number: PCT/US2006/035223
Authority: WO
Inventors: Craig A. Chmielewski; Jason B. Walker; Roy A. Ash; Terry M. Finerman
Original assignee: L&L Products Inc
Current assignee: L&L Products Inc
Priority date: 2005-09-09
Filing date: 2006-09-11
Publication date: 2008-01-24
Anticipated expiration: 2008-03-09
Also published as: WO2008010823A3

Abstract

A continuous fiber reinforced thermoplastic composite based on a thermoplastic epoxy resin matrix, as well as methods for its manufacture and application are described. The improved composite is advantageous because it provides for processing flexibility, while retaining the strength and toughness of conventional composites, minimizes void content by providing for impregnation of porous media by low viscosity liquids, and provides for effective adhesion between the thermoplastic matrix phase based on epoxy chemistry and the porous media to improve the resulting strength.

Description

-I-

THERMOPLASTIC BASED COMPOSITES

BACKGROUND OF INVENTION a. Field of Invention

The invention relates generally to thermoplastic based composites, and, more particularly to thermoplastic based composites for use as light weight armor for military vehicles, land vehicles, and lightweight structures and buildings.

b. Description of Related Art

Generally, continuous fiber reinforced composite materials are based on a thermosetting resin as the continuous matrix phase and continuous fiber bundles or woven mats as the fiber phase. A wide variety of thermosetting materials are available and used for the matrix phase, however, two part epoxy resin or polyester resin systems are most common. These resin systems are typically very low in viscosity prior to cure which makes them well suited to manufacturing composite materials. Low viscosity thermosetting resins easily wet-out and impregnate fiber bundles or mats, resulting in low void fraction composite materials, and lend themselves to a variety of composite prepregging techniques such as pultrusion and compression molding. One characteristic, and potential limitation, of thermoset based composite materials is that they have to be shaped to their final form before/during curing because once the composite is cured, its structure is chemically locked in place through chemical crosslinking of the continuous resin phase through the application of heat, pressure and time. Accordingly, a finished thermoset composite part can no longer be reshaped, even with additional heat and applied pressure.

A need remains for a composite material that can be heated, shaped, and solidified preferably repeatedly, so that processing flexibility not normally associated with a continuous fiber composite can be achieved. One method for achieving this processing flexibility is to replace the thermoset matrix and incorporate a thermoplastic as the continuous phase. Thermoplastics typically are comprised of high molecular weight polymers which display high viscosity in their melt state. As a result, thermoplastics are extremely difficult to process with continuous fibers to produce a composite material. Thermoplastics do not easily wet-out and impregnate fiber bundles or mats, and, when attempted, often result in high void fraction composite materials. Also, because of their high viscosity, thermoplastics themselves do not lend themselves to being processed using industry standard composite prepregging techniques, such as pultrusion and compression molding.

The invention provides for a set of particular low viscosity materials — reactants - that are easily impregnated into continuous fiber bundles or mats and then chemically react (polymerize) in-situ through the use of one or all of the set of temperature, pressure or time to produce a high molecular weight thermoplastic matrix composite material. Moreover, this invention includes the product of this manufacturing method, being a continuous fiber reinforced composite material where the matrix phase is a thermoplastic that enables the processing flexibility of thermoplastic composites, such as reforming and reshaping, as described above. Furthermore, the invention provides the strength and toughness usually associated with continuous fiber composites as well as the processing versatility of thermoplastics via thermoforming-type processes. A need further remains for a composite material that is lightweight and retains the required performance standards in connection with ballistics testing. A first layer of the composite structure should be designed to blunt the tip of an incoming projectile or otherwise damage the projectile, so that it will not pierce as deeply into the composite. A second layer of the composite structure should be designed for energy absorption.

SUMMARY OF INVENTION

In an exemplary embodiment, the invention provides a method of forming a thermoplastic basis continuous fiber reinforced composite material, including the steps of providing a thermoplastic material and impregnating the thermoplastic material into continuous fiber reinforcements. The thermoplastic material may be selected from a polyetheramine or a mixture of epoxies and amines that are precursors to the polyetheramine.

The improved composite and method of forming composite has several advantages. First, the improved composite and method thereof provide processing flexibility, while retaining the strength and toughness of conventional composites. Second, the use of low viscosity liquids for impregnating porous media or fiber reinforcements provides for simple mixing strategies and minimizes the void content of the resulting composite. Third, effective adhesion between the thermoplastic matrix based on epoxy chemistry and the porous media or fiber reinforcements improves the strength of the resulting composite. These and other features and objects of this invention will become apparent to one skilled in the art from the following detailed description illustrating features of this invention by way of example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is predicated on the use of a particular class of thermoplastic resins, the method for their incorporation/ impregnation of continuous fiber bundles or mats — woven or otherwise — and the applications and uses for the resulting thermoplastic based composite.

In an exemplary embodiment, it is contemplated that multiple different thermoplastic materials from a class known as hydroxyl-functionalized polyetheramine resin, also referred to as thermoplastic epoxy resin (TPER), may be employed in the present invention. In one embodiment, the thermoplastic material is a compound that includes at least one epoxy group and at least one amine group. Examples of such materials are poly(hydroxy ethers) or polyetheramines and more particularly, thermoplastic hydroxyl-functionalized polyetheramines (e.g., polyhydroxy amino ethers (PHAE)), which are particularly suitable as thermoplastics for the present invention. These polyetheramines are typically formed through the reaction of one or more polyfunctional and preferably difunctional amines with one or more polyfunctional and preferably difunctional epoxy resins for forming a primarily (i.e., at least about 70, 80, 90 % or more) linear hydroxyl-functionalized polyetheramine resin. Advantageously, the molecular weight of the polyetheramine resin can be modified by varying the reactant ratios of amine to epoxy.

One exemplary polyetheramine suitable for use in the present invention has repeating units represented by the formula:

wherein each A is individually a divalent amine moiety; each B is individually a divalent aromatic moiety; each Y is divalent oxygen or sulfur, R¹ is hydrogen or a monovalent hydrocarbon and x is a number sufficient to reduce the oxygen permeability of the polyether to a value which is measurably lower than that of a polyether consisting of repeating units represented by the formula:

OH

•e ArOCH₂CCH₂O^- R»

wherein Ar is the divalent radical resulting from the removal of two hydroxyl moieties from bisphenol A.

Another suitable polyetheramine is represented by the structural formula:

OH OH OH OH I

I t I I

-(-YCH₂CCH₂-A- CH₂CCH₂YB)_x-*- YCH₂CCH₂YBYCH₂CCHaYB)T=_X

Rl R¹ Rl Rl

wherein B, R¹, Y and x are as previously defined, and each A is individually an amine moiety represented by the formula:

T R² Z

-> in which R is C.sub.2 -C.sub.10 hydrocarbylene; R.sup.3 is a C.sub.2 -C.sub.lO alkylene; R.sup.4 is a C.sub.2 -C.sub.20 hydrocarbylene; Z is alkylamido, hydroxy, alkoxy, alkylcarbonyl, aryloxy, arylcarbonyl, halo, or cyano. For purposes of this invention, "hydrocarbyl" is a monovalent hydrocarbon such as alkyl, cycloalkyl, aralkyl, or aryl and "hydrocarbylene" is a divalent hydrocarbon such as alkylene, cycloalkylene, aralkylene or arylene.

In an exemplary embodiment, this invention is a reactive process for preparing the hydroxy-functional polyetheramine which comprises contacting a diglycidyl ether of a dihydric phenol with an amine having only two hydrogens under conditions sufficient to form the polyetheramine.

In exemplary embodiments of the invention, each A of the polyetheramines represented by Formula I is individually represented by one of the formulas:

T z

— N N N-,

— N—R⁴— N—

I I Z^Z in which R.sup.2 is C.sub.2 -C. sub.10 alkylene or phenylene, with ethylene being most preferred; R.sup.3 is C.sub.2 -C.sub.10 alkylene or substituted C.sub.2 -C.sub.10 alkylene wherein the substituent(s) is alkylamido, hydroxy, alkoxy, halo, cyano, aryloxy, alkylcarbonyl or arylcarbonyl, with ethylene being most preferred; R.sup.4 C.sub.2 -C.sub.20 alkylene or substituted C.sub.2 -C.sub.20 alkylene wherein the substituent(s) is alkylamido, hydroxy, alkoxy, halo, cyano, aryloxy, alkylcarbonyl or arylcarbonyl, with ethylene and p-xylylene being most preferred; Z is alkylamido, hydroxy, alkoxy, halo, aryloxy, cyano, alkylcarbonyl or arylcarbonyl, with alkylamido, hydroxy and alkoxy being most preferred. Each B is individually carbonyldiphenylene, m-phenylene, p-phenylene, sulfonyldiphenylene, isopropylidenediphenylene, biphenylene, biphenylene oxide, methylenediphenylene, biphenylene sulfide, naphthylene, biphenylenecyanomethane, 3,3 '-dialkyldiphenyleneisopropylidene, 3,3',4,4'-tetraalkyldiphenyleneisopropylidene and the corresponding alkyl-substituted derivatives of the other named divalent aromatic moieties wherein the substituent(s) is a monovalent moiety which is inert in the reactions used to prepare the polyetheramine. More preferably, A is represented by the formulas:

-N-, R²

— N N-,

wherein each R.sup.2 is individually a C.sub.2 -C.sub.5 alkylene such as ethylene, propylene, butylene or pentylene; R.sup.3 is a C.sub.2 -C.sub.5 alkylene such as ethylene, propylene, butylene or pentylene; R.sup.4 is a C.sub.2 -C. sub.10 alkylene such as ethylene, propylene, butylene or pentylene, or arylene such as phenylene or xylylene; Z is alkylamido, hydroxy or alkoxy; B is isopropylidenediphenylene or phenylene; R.sup.l is hydrogen or methyl and x is in the range from about 0.5 to 1.0. The polyetheramines are most preferably those represented by the formula:

; OH OH OH OH ^"I

I l I l

OCH2CHCH2— A— CH2CHCH2θB-te-fOCH2CHCH2θBOCH₂CHCH2θB⁾r-T-j — ^v' wherein A, B and x are as defined above, w is a number from 10 to 400 and each V and VI is individually a secondary amine such as

H / y

HOCH₂CH₂N-- or HN N—

or a tertiary amine such as

The polyetheramines employed in this invention are suitably prepared by contacting one or more of the diglycidyl ethers of a dihydric phenol with an amine having two amine hydrogens and represented by AH.sub.2 wherein A is as previously defined under conditions sufficient to cause the amine moieties to react with epoxy moieties to form a polymer backbone having amine linkages, ether linkages and pendant hydroxyl moieties. Conditions conventionally employed in the reaction of diglycidyl ethers with amines to form amine linkages and pendant hydroxyl groups are suitably employed in preparing the resins of this invention. Examples of such suitable conditions are set forth in U.S. Pat. No. 3,317,471, which is hereby incorporated by reference in its entirety. In general, however, the process for preparing the polymers including the copolymers is carried out so that the unreacted epoxy groups in the finished polyether are minimized. By minimizing the epoxy groups in the polyetheramine, the essential thermoplastic character of the polyetheramine can be retained. Preferred conditions for preparing such resins are set forth in the following working examples.

In the preparation of copolymers (i.e., where x in the aforementioned formulae is less than one), a dihydric phenol is employed in addition to the amine. In such copolymerizations, while it is possible to subject a mixture of the diglycidyl ether(s), amine(s) and dihydric phenol(s) to copolymerization conditions, it is sometimes desirable to employ a staged addition procedure wherein the dihydric phenol is added before the amine is introduced or after essentially all of the amine has reacted with the diglycidyl ether. In the preparation of the copolymers wherein the reaction of dihydric phenol with diglycidyl ether is desired, conditions are employed to promote such reactions such as described in U.S. Pat. No. 4,647,648, which is hereby incorporated by reference in its entirety.

The diglycidyl ethers of the dihydric phenols are preferably the diglycidyl ethers of resorcinol, hydroquinone, 4,4'-isopropylidene bisphenol (bisphenol A), 4,4'- dihydroxydiphenylethylmethane, 3,3'-dihydroxydiphenyldiethylmethane, 3,4'- dihydroxydiphenylmethylpropylmethane, 4,4'-dihydroxydiphenyloxide, 4,4'- dihydroxydiphenylcyanomethane, 4,4'-dihydroxybiphenyl, 4,4'- dihydroxybenzophenone (bisphenol-K), 4,4'-dihydroxydiphenyl sulfide, 4,4'- dihydroxydiphenyl sulfone, 2,6-dihydroxynaphthalene, l,4'-dihydroxy-naplithalene, catechol, 2,2-bis(4-hydroxyphenyl)-acetamide, 2,2-bis(4-hydroxyphenyl)ethanol, 2,2- bis(4-hydroxyphenyl)-N-methylacetamide, 2,2-bis(4-hydroxy-phenyl)-N,N- dimethylacetamide, 3,5-dihydroxyphenyl-acetamide, 2,4-dihydroxyphenyl-N- (hydroxyethyl)-acetamide, and other dihydric phenols listed in U.S. Pat. Nos. 3,395,118, 4,438,254 and 4,480,082 which are hereby incorporated by reference as well as mixtures of one or more of such diglycidyl ethers. Of these preferred diglycidyl ethers, those of bisphenol-A, hydroquinone, and resorcinol are more preferred, with the diglycidyl ether of bisphenol-A being most preferred.

Examples of preferred amines include piperazine and substituted piperazines, e.g., 2-(methylamido)piperazine and dimethylpiperazine; aniline and substituted anilines, e.g., 4-(methylamido)aniline, 4-methoxyanilme, 4-tert-butylaniline, 3,4- dimethoxyaniline and 3,4-dimethylaniline; alkyl amines and substituted alkyl amines, e.g., butylamine and benzylamine; alkanol amines, e.g., 2-aminoethanol and 1- aminopropan-2-ol; and aromatic and aliphatic secondary diamines, e.g., 1,4- bis(methylamino)benzene, l,2-bis(methylamino)ethane and N,N'-bis(2- hydroxyethyl)ethylenediamine. Of these preferred amines, 2-aminoethanol and piperazine are most preferred.

Several methods can be used to produce continuous fiber reinforced thermoplastic composites, containing TPER as the matrix material. In one exemplary embodiment, TPER is converted into a thin film of thickness less than about 0.010 inches but greater than about 0.0005 inches, but more preferably less than about 0.007 inches but greater than about 0.001 inches and most preferably less than about 0.005 inches and greater than about 0.002 inches. This film may then be laid-up as single sheets in layers between rows of fiber reinforcement such as fiber bundles or mats in exemplary embodiments. This layered stack of TPER sheet and continuous fiber is then consolidated under heat and pressure. Examples of such consolidation processes include, but are not limited to, compression molding and autoclaving. According to another exemplary embodiment, TPER may be converted into a fine powder which is uniformly dispersed between layers of continuous glass fibers or mats. This layered stack of TPER powder and continuous fiber is then consolidated under heat and pressure. Examples of such consolidation processes include, but are not limited to, compression molding and autoclaving.

In another exemplary embodiment, the high molecular weight TPER is not initially used to make a thermoplastic composite material. Instead, the TPER reactants are initially used. In this exemplary embodiment, the reactants of the TPER are mixed, resulting in a low viscosity reactive blend. When liquid monomers are used, a low viscosity is preferred for impregnation of the porous medium in order to maximize the wetting of the porous medium and minimizing the number of voids in the composite panels. The reactants may be mixed in an injector chamber, and the reactants should be well-mixed.

The blend is then impregnated into a porous medium, such as a fiber tow, mat, or woven or unwoven form. Once impregnated, the liquid will chemically react (chain extend), building molecular weight and resulting in an in-situ formed thermoplastic polymer matrix composite. The reaction may be controlled by temperature and time at temperature. The epoxy-amine polymerization reaction is highly exothermic. Reaction control may be attained by keeping temperature build-up small, thereby minimizing the rate of polymerization. Heat may be added to the system when polymerization is desired. In an exemplary embodiment, a cooling jacket may be utilized in reaction control.

In another exemplary embodiment, a combination of both liquid monomers and TPER film may be used, such that the liquid monomers may be impregnated into the fiber layers and the film may be sandwiched between fiber layers.

In addition to the mixing step and injection step, a third step may be employed in series or in parallel to the mixing and injecting steps. The third step comprises consolidation of the porous substrate. Two exemplary consolidating steps are resin transfer molding and compression molding. In resin transfer molding, a low viscosity liquid is injected into a pre-consolidated porous substrate. In compression molding, the porous substrate is consolidated following impregnation. The properties of the final composite are determined by many factors, such as the degree of consolidation and polymer matrix properties. In an exemplary embodiment, the degree of consolidation may be about between 10% to 60% matrix material. The polymer matrix may attain sufficient molecular weight as to allow the composite material stiffness and strength and toughness for its use in various structural applications. In an exemplary embodiment, the structural application may be vehicle body armor, acting as a barrier to a variety of projectiles.

The composite may be about 10% to about 50% by volume thermoplastic resin content in an exemplary embodiment. More preferably, the composite may be about 15% to about 40% by volume thermoplastic resin content. Most preferably, the composite may be about 20% to about 35% by volume thermoplastic resin content. In an exemplary embodiment of the above-described process, a liquid epoxy resin (LER) and a diamine may be mixed in a high speed mixer or by hand. The LER may be DER 331 manufactured by Dow Chemical Company. The reactants may be manufactured to an epoxy equivalent weight (EEW) specification of 172 to 192, and a viscosity specification of 11,000 to 14,000 cps at 25 ° C. Although these specifications are mentioned in detail, it is understood by those of ordinary skill in the art that the LER may comprise any EEW range depending upon the desired properties of the TPER. At higher EEWs, the viscosity of the LER increases, requiring a modified feed system. At lower EEWs, the TPER physical properties are improved. The difunctional amine may be monoethanolamine (MEA) manufactured by Dow Chemical Company. The ratio of the reactants may be varied, but the LER to MEA ratio may be generally approximately 0.90 to 1.05, on a molar basis. For the DER 331/MEA exemplary embodiment, the LER (DER 331) to MEA ratio may be generally approximately 0.975 to 0.985, on a molar basis. This may correspond to an LER (DER 331) to MEA ratio of approximately 5.99 to 6.06, on a mass basis.

The molecular weight of the liquid monomers and accordingly, viscosity, may be controlled by modifying the ratio of MEA to LER, by modifying the purity of the LER, and by adding small amount of trifunctional or tetrafunctional monomers that will still avoid cross-linking. The blended ingredients may then be applied to pre- woven 3-D, S-2 fiberglass mats, and to the bottom and top of a compression tool. The glass mats may be stacked with the number of mats being determined by the desired end thickness. Generally, the glass fibers represent approximately 72% weight of the composite. The compression tool may be closed and placed in a heated press. The press is engaged, providing a force to consolidate the glass mats. The temperature, vacuum, lay-up procedure, tool design may affect composite void content.

The composite may be formed into panels. For example, the panels may range in size from 6" x 6" and 2' x 2'. The panels may be approximately 4' x 8' in another exemplary embodiment. Reshaping of the panels may be accomplished by heating the panels in an oven and bending the composite around a form, such as a cylindrical mandrel, and allowing the reshaped panel to cool The reshaped composite may maintain a strong performance in ballistic testing.

The composite may be manufactured by a continuous process in an exemplary embodiment. A prepreg may be formed, and a hot press may be used to finish the reaction.

A first layer of a composite that is designed for projectile damage may comprise a layer of tiles, hi an exemplary embodiment, the titles may comprise ceramic, and the tiles may be relatively small. The following examples further illustrate the invention.

A first example illustrates construction of the invention by mixing the TPER reactants, pouring the low viscosity liquids between layer of glass mats and then applying pressure through a compression molding process to impregnate and consolidate the glass mats. The application of heat is used to initiate polymerization of the chemical reactants leading to the composite matrix comprising a high molecular weight thermoplastic. Specifically, a liquid epoxy resin from Dow Chemical Company (Midland, MI) named DER 331, having an epoxy equivalent weight between 182 and 192, may be well mixed at room temperature with monoethanolamine (MEA) from INEOS Oxide (Freeport, Tx) at a ratio of about 0.8559 to about 0.1441 respectively. Thus, the weight ratio of epoxy to MEA is about 5.961 and the approximate molar ratio is about 0.974. This low viscosity liquid blend may then be poured at equal amounts between 10 layers of glass to give an overall resin to glass content of 0.24 to 0.76 by weight. The particular glass mats of this example may be composed of S-2 glass woven in a 3-D weave having a 50 oz weight. The compression molding procedure used may comprise the following steps: (1) Set the glass/resin lay-up from above into the pre-heated (100 ⁰F) compression molded tool and close the platens to 150 psi; (2) Turn the press temperature up to 150 ⁰F and raise the pressure to 250 psi; (3) About 30 minutes later increase the pressure to 1000 psi; (4) About 60 minutes later remove heat from the press and start the cooling process. This process produces a fiber reinforced thermoplastic composite panel having an areal density of about 4.5 lbs/sq-ft at 0.49 inches thick.

A second example is similar to the first example in that the same TPER reactants may be mixed in the same ratios but poured at equal amounts between 10 layers of glass to give an overall resin to glass content of about 0.18 to about 0.82 by weight. Identical glass mats may be used and identical compression molding process to produce the fiber reinforced thermoplastic composite panel may be used. However, to one side of the composite panel a ceramic strike face may be added. This strike face may be composed of 2 inch by 2 inch 98.5% Alumina squares adhered to the panel. This gives the panel an overall areal density of about 9.6 lbs/sq-ft at about 0.73 inches thick. A third example illustrates use of the TPER film to construct a composite panel.

That is, the TPER in this example is not in-situ polymerized, but manufactured and converted into thin film prior to the composite manufacture process. In this example, during composite manufacture, about 0.010 inch thick TPER film may be placed at the top and bottom of the composite panel. Between each of 9 fiber mats, an about 0.005 inch thick film of TPER may be placed. The glass mats used in this example may be the S-2 glass woven in a 3-D weave having a 50 oz weight — same as used in Example 1. In this example, the layered perform may be placed in a compression press pre-set at 350 ⁰F and pressed to 250 psi pressure. When the temperature stabilizes, the pressure may be increased to 500 lbs. Then 30 minutes later the pressure may be increased to 1500 lbs. Following an hour at 1500 lbs the heat may be removed and cooling of the tool may begin. The overall composition of the composite panel of Example 3 may be about 25 % resin and about 75 % glass by weight.

Table I below compares ballistic testing of the composite samples of Examples 1, 2 and 3 to the military specification V50 mil-std-662. The V50 values represent the projectile speed at which 50% of the projectiles pass through the composite panel.

Table I

The improved thermoplastic based composite has several advantages in addition to providing process flexibility while retaining the strength and toughness of conventional continuous fiber composites. The use of low viscosity liquids as the starting point of the polymerization allows for simple mixing strategies, such as static mixing or impingement mixing. Also, the use of a chemical system that allows in-situ polymerization of a thermoplastic to form the composite matrix offers ease of substrate impregnation because of the low viscosity of the pre-reacted liquid mixture. This is advantageous when attempting to "wet-out" the entire porous substrate's surface so as to minimize the void content of the composite. The manufacture of thermoplastic based continuous fiber composites, without the in-situ polymerization step, would otherwise involve trying to impregnate a high viscosity plastic into a porous substrate. With such high viscosity processes, the final void content may typically be very high.

Further, because the thermoplastic described herein is based on epoxy chemistry, it is a good adhesive. The adhesive properties improve the making of a composite material utilizing a porous substrate such as a fiber glass mat. Effective adhesion between the TPER matrix and the porous substrate result in improved interfacial strength between the phases, and is ultimately realized by the exceptional strength and toughness of the composite material. The improved adhesive properties of the TPER matrix also enable the composite to bond well to a variety of surfaces, such as, but not limited to, steel, aluminum, and ceramic. Although particular embodiments of the invention has been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those particular embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A method of forming a thermoplastic based continuous fiber reinforced composite material, comprising the following steps: providing a thermoplastic material, said thermoplastic material selected from a polyetheramine or a mixture of epoxies and amines that are precursors to said polyetheramine; and impregnating said thermoplastic material into continuous fiber reinforcements .

2. A method of using a thermoplastic based continuous fiber reinforced composite material, comprising the following steps: providing a thermoplastic material, said thermoplastic material selected from a polyetheramine or a mixture of epoxies and amines that are precursors to said polyetheramine, that is impregnated into continuous fiber reinforcements to form a thermoplastic composite material; applying said thermoplastic composite material to a structure of an article of manufacture; and reshaping said thermoplastic composite material with the application of heat and pressure.

3. A method in accordance with any of the preceding claims, wherein said thermoplastic material is based on reactive blends of chemically difuctional amines and chemically difuctional epoxy resins.

4. A method in accordance with any of the preceding claims, wherein said amines comprise monoethanol amine and said epoxy resins comprise Bisphenol A based liquid epoxy resins.

5. A method in accordance with any of the preceding claims, wherein said continuous fiber reinforcements comprise one or more of the following: glass, carbon, polyaramid, polyethylene or polypropylene in the form of bundles, tows, woven or non- woven mats.

6. A method in accordance with any of the preceding claims, wherein the reactants of said thermoplastic material are mixed and impregnated into said fiber reinforcements as a low viscosity liquid.

7. A method in accordance with any of the preceding claims, wherein the liquid impregnated reinforcement fibers are consolidated under pressure.

8. A method in accordance with any of the preceding claims, wherein heat is added to said low viscosity liquid and said reinforcement fibers after consolidation under pressure to facilitate polymerization of said low viscosity liquid.

9. A method in accordance with any of the preceding claims, wherein vacuum is applied to said reinforcement fibers after consolidation under pressure to facilitate the removal of voids.

10. A method in accordance with any of the preceding claims, wherein trifunctional or tetrafunctional monomers are added to said thermoplastic material as an additional reactant.

11. A method in accordance with any of the preceding claims, further comprising the following steps: converting said thermoplastic material into a film; and plying said film between layers of continuous fiber reinforcements.

12. A method in accordance with any of the preceding claims, wherein said film and said fiber reinforcements are consolidated under pressure and temperature.

13. A method in accordance with any of the preceding claims, wherein vacuum is applied to said fiber reinforcements after consolidation to facilitate the removal of voids.

14. A method in accordance with any of the preceding claims, further comprising the following steps: converting said thermoplastic material into a powder; and dispersing said powder between layers of continuous fiber reinforcements .

15. A method in accordance with any of the preceding claims, wherein said powder and said reinforcement fibers are consolidated under pressure and temperature.

16. A method of any of the preceding claims, wherein vacuum is applied to fiber reinforcements after consolidation to facilitate the removal of voids.

17. A method of using a thermoplastic based continuous fiber reinforced composite material in accordance with any of the preceding claims, wherein said W

-18-

thermoplastic composite material is shaped into armor for protection from blast or ballistic events.

18. A method of using a thermoplastic based continuous fiber reinforced composite material in accordance with any of the preceding claims, wherein said thermoplastic composite material is shaped into body panels for the transportation industries.

19. A composite, comprising: a porous medium; and a blend of liquid monomers injected into said porous medium, wherein said blend comprises difunctional epoxy resin and difunctional amine and said blend is polymerized to form an in-situ thermoplastic polymer matrix phase.

20. A composite in accordance with any of the preceding claims, wherein a plurality of ceramic tiles are affixed to said composite.