CN106008797A - Polyacrylonitrile gradient copolymer and controllable synthesis method thereof - Google Patents

Abstract

The invention provides a polyacrylonitrile gradient copolymer and a controllable synthesis method thereof, the method has simple process, wide applicable monomer range and high synthesis efficiency, and comprises the following steps: placing monomer acrylonitrile, comonomer, ligand, initiator and zero-valent metal catalyst in a solvent, and at 25-100 ℃, the monomer acrylonitrile and the comonomerAnd carrying out polymerization reaction on the polymeric monomer and the initiator, and controlling the molecular weight of the obtained polyacrylonitrile gradient copolymer by adjusting the reaction time. M of polyacrylonitrile gradient copolymer obtained by synthesis_w/M_nThe ratio is small, which indicates that the molecular weight distribution is narrow, the purity is high, and the actual molecular weight of the obtained polymer is consistent with the theoretical molecular weight.

Description

A kind of polyacrylonitrile gradient copolymer and its controllable synthesis method

technical field

The invention relates to the technical field of polymer synthesis, in particular to a controllable synthesis method of a polyacrylonitrile gradient copolymer.

Background technique

Because "active"/controllable free radicals can design the structure, molecular weight, and molecular weight distribution of polymers, they have attracted widespread attention from scientists. At present, the hot research mainly includes atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization and zero-valent metal catalyzed controllable radical polymerization. Compared with the former two polymerization methods, "living" controllable free radical polymerization catalyzed by zero-valent metals, especially zero-valent copper, has the characteristics of fast reaction speed, mild reaction conditions and good economy, so it has been widely reported.

Secondly, the sequence distribution of repeating units in copolymers has a great influence on the properties of polymers, so scientists continue to improve the performance of polymers by controlling the sequence distribution of units. And because the composition of the gradient polymer will change continuously with the chain growth of the copolymer, it will bring many excellent properties to the polymer.

As we all know, acrylonitrile is widely used in synthetic fibers, synthetic rubber and synthetic resins, so it is particularly important to study the properties of polyacrylonitrile gradient copolymers. Most of the current reports on the synthesis of polyacrylonitrile gradient copolymers are based on nitrogen-oxygen-stabilized radical polymerization, atom transfer radical polymerization and reversible addition-fragmentation chain transfer polymerization. However, the method of constructing polyacrylonitrile gradient copolymers through zero-valent copper-catalyzed "living" controlled free radical polymerization has not been reported so far.

In view of the above-mentioned defects, the designer actively researches and innovates in order to create a synthetic method for constructing polyacrylonitrile gradient copolymers through zero-valent copper-catalyzed "active"/controllable free radical polymerization, making it more industrially useful. use value.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a polyacrylonitrile gradient copolymer and a controllable synthesis method thereof, which has simple process, wide range of applicable monomers and high synthesis efficiency.

The controllable synthesis method of polyacrylonitrile gradient copolymer of the present invention comprises the following steps: placing monomer acrylonitrile, comonomer, initiator, zero-valent metal catalyst and the ligand of zero-valent metal catalyst in a solvent, At 25-100°C, the acrylonitrile monomer and the comonomer are polymerized, and the molecular weight of the obtained polyacrylonitrile gradient copolymer is controlled by adjusting the reaction time.

Further, the zero-valent metal catalyst is zero-valent copper or zero-valent iron catalyst.

Further, the molar ratio of the monomer acrylonitrile, comonomer, ligand, initiator and zero-valent metal catalyst is 100-300:100:1-3:1-3:1-3.

Further, the volume ratio of the comonomer to the solvent is 100:50-200.

Further, the comonomer is one or more of methyl methacrylate and its derivatives, methyl acrylate and its derivatives, and styrene and its derivatives, as shown in FIG. 1 .

Further, the initiator is α-chlorophenylethane, α-bromophenylethane, benzyl chloride, benzyl bromide, α-ethyl chloropropionate, α-ethyl bromopropionate, α- One or more of ethyl bromoisobutyrate, α-chloroacetonitrile, α-chloropropionitrile and 1-phenylethyl bromide.

Further, the ligands are pentamethyldiethylenetriamine, hexamethyltriethylenetetramine, diethylenetriamine, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine Amine, tris(2-pyridylmethyl)amine, tris(2-aminoethyl)amine, 1,10-phenanthroline, 1,4,8,11-tetramethyl-1,4,8,11 - one or more of tetraazacyclotetradecane and 2,2'-bipyridine.

Further, the solvent is one or more of dimethylsulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

In the polyacrylonitrile gradient copolymer of the present invention, the molecular weight distribution coefficient of the polyacrylonitrile gradient copolymer is M _w /M _n = 1.10-1.60

By means of the above scheme, the present invention has the following advantages:

The present invention provides a controllable synthesis method of polyacrylonitrile gradient copolymer, which successfully synthesizes polyacrylonitrile gradient copolymer through "active"/controllable free radical polymerization catalyzed by zero-valent copper. Mild conditions, wide range of applicable comonomers, fast reaction rate, high yield, etc., are suitable for industrial production; the _Mw / _Mn ratio of the synthesized polyacrylonitrile gradient copolymer is small, indicating that the molecular weight distribution is narrow and the purity is high. The actual molecular weight of the polymer is consistent with the theoretical molecular weight.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention and accompanying drawings are described in detail below.

Description of drawings

Fig. 1 is the molecular structure diagram of comonomer in the present invention;

Fig. 2 is the nuclear magnetic hydrogen spectrogram of the polymer of embodiment 1 in the present invention;

Fig. 3 is the relationship figure between monomer conversion rate and molecular weight and molecular weight distribution when embodiment 1 and embodiment 2 are copolymerized among the present invention;

Fig. 4 is the SEC outflow curve figure of the different polyacrylonitrile gradient copolymers that embodiment 1 obtains in the present invention;

Fig. 5 is the SEC outflow curve figure of the different polyacrylonitrile gradient copolymers that embodiment 2 obtains in the present invention;

Fig. 6 is the relation diagram of the composition and the transformation rate of the copolymer obtained in embodiment 1 in the present invention;

Fig. 7 is a schematic diagram of the obtained polyacrylonitrile gradient copolymer.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

Acrylonitrile 0.75mL (11.2mmol), comonomer 1 methyl methacrylate 0.6mL (5.6mmol), catalyst copper powder 7.2mg (0.112mmol), initiator 2-bromopropionate ethyl 20.2mg (0.112 mmol), ligand 2,2-bipyridine 17.5mg (0.112mmol) and solvent dimethyl sulfoxide 1mL were added to the reaction vessel, a stirrer was added, and after 3 standard freeze-pump-thaw inflation cycles, the Protective gas down seal tube. Place the sealed ampoule in a blender, react at 25°C for a certain period of time, take out the sealed tube, open the sealed tube, dissolve it with a small amount of solvent, pour it into a large amount of precipitant, leave it overnight, suction filter, and dry The polyacrylonitrile gradient copolymer can be obtained, and its structural schematic diagram is shown in FIG. 7 .

The polyacrylonitrile gradient copolymer is characterized by the following tests:

The proton peaks of the repeating unit acrylonitrile and methyl methacrylate can be found in the NMR spectrum shown in Figure 2, indicating that the two monomers have been successfully inserted into the polymer chain; as shown in Figure 3, The relationship between conversion rate and molecular weight and molecular weight distribution during the copolymerization of acrylonitrile and methyl methacrylate, it can be seen from the figure that the molecular weight of the polymer increases with the increase of conversion rate, and the molecular weight distribution is relatively Low; the SEC efflux curve figure of polyacrylonitrile gradient copolymer as shown in Figure 4, finds that its efflux curve all presents unimodal distribution from the figure, and these data all show that polymerization process is " active "/ controllable; Fig. 6 is the relationship between the composition and conversion rate of the obtained copolymer. It can be seen from the figure that as the conversion rate increases, the number of acrylonitrile units in the copolymer continues to increase, while the number of units of methyl methacrylate decreases continuously. , which also shows that the obtained polymer is a polyacrylonitrile gradient copolymer, and its structural schematic diagram is shown in FIG. 7 .

Example 2

Acrylonitrile 0.75mL (11.2mmol), comonomer 1 methyl methacrylate 0.6mL (5.6mmol), catalyst copper powder 7.2mg (0.112mmol), initiator 2-bromopropionate ethyl 20.2mg (0.112 mmol), ligand 2,2-bipyridine 17.5mg (0.112mmol) and solvent N,N-dimethylformamide 1mL were added to the reaction vessel, a stirrer was added, and after 3 standard freezing-pumping-thawing After the inflation cycle, the tube is sealed under protective gas. Place the sealed ampoule in a blender, react at 25°C for a certain period of time, take out the sealed tube, open the sealed tube, dissolve it with a small amount of solvent, pour it into a large amount of precipitant, leave it overnight, suction filter, and dry The polyacrylonitrile gradient copolymer can be obtained.

The polyacrylonitrile gradient copolymer is characterized by the following tests:

As shown in Figure 3, the relationship between conversion rate and molecular weight and molecular weight distribution when carrying out acrylonitrile and methyl methacrylate copolymerization, it can be seen from the figure that the molecular weight of the polymer increases with the increase of conversion rate Large, and the molecular weight distribution is low; Figure 5 is the SEC efflux curve of the polyacrylonitrile gradient copolymer, from which it is found that the efflux curves are all unimodal, and these data indicate that the polymerization process is "active"/controllable of.

In summary, the present invention successfully constructs polyacrylonitrile gradient copolymers based on zero-valent metal-catalyzed "active"/controllable free radical polymerization, and the method has a fast reaction speed and mild reaction conditions.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements can be made without departing from the technical principle of the present invention. and modifications, these improvements and modifications should also be considered as the protection scope of the present invention.

Claims (9)

1. the synthetic method of a polyacrylonitrile gradient copolymer, it is characterised in that include following step Rapid: by monomers acrylonitrile, comonomer, initiator, zero-valent metal catalyst and described zero The part of valency metallic catalyst is placed in solvent, carries out polyreaction, obtain at 25-100 DEG C Polyacrylonitrile gradient copolymer.

Synthetic method the most according to claim 1, it is characterised in that: described zero-valent metal is urged Agent is copper or ferrum.

Synthetic method the most according to claim 1 and 2, it is characterised in that: described monomer third The mol ratio of alkene nitrile, comonomer, part, initiator and zero-valent metal catalyst is 100-300: 100:1-3:1-3:1-3。

Synthetic method the most according to claim 1, it is characterised in that: described comonomer with Solvent volume is than for 100:50-200.

Synthetic method the most according to claim 1, it is characterised in that: described comonomer is Methyl methacrylate and derivant, acrylic acid methyl ester. and derivant thereof and styrene and spread out One or more in biology.

Synthetic method the most according to claim 1, it is characterised in that: described initiator be α- Chlorobenzene ethane, alpha-brominated vinylbenzene, benzyl chloride, benzyl bromide a-bromotoluene, α-chloro-propionicacid ethyl ester, α-bromine Ethyl propionate, alpha-brominated ethyl isobutyrate, α-chloroacetonitrile, α-chloroethyl nitrile and 1-phenylethyl bromine In one or more.

Synthetic method the most according to claim 1, it is characterised in that: described part is five first Base diethylenetriamine, hexamethyl trien, diethylenetriamine, N, N, N', N'-tetra-(2- Picolyl) ethylenediamine, three (2-pyridylmethyl) amine, three (2-amino-ethyl) amine, 1,10-be luxuriant and rich with fragrance In sieve quinoline, 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclododecane four decane and 2,2'-bipyridyl one Plant or several.

Synthetic method the most according to claim 1, it is characterised in that: described solvent is diformazan One or more in sulfoxide, N,N-dimethylformamide and DMAC N,N' dimethyl acetamide.

9. the polyacrylonitrile gradient copolymer that the synthetic method as described in claim 1-8 is arbitrary obtains, It is characterized in that: the molecular weight distribution index of described polyacrylonitrile gradient copolymer M_w/M_n=1.10-1.60.