Method for preparing accurate polymer network
The invention discloses a method for preparing an accurate polymer network. The number of azide functional groups at the tail end of a polymer is controlled accurately by using a method combining reversible addition-fragmentation chain transfer (RAFT) and click chemistry, so that the number of crosslinking points is controlled and a regular polymer cross-linked network structure is prepared. In the method disclosed by the invention, gel in the polymer network is generated by performing a click reaction on two or more accurately-controlled functional end group azide or alkyne functional groups (E) at the tail end of a polymer chain and two or more end alkynyl or azide functional groups (E) via multiple steps of RAFT. The method has the advantages of accurate controllability of the number of crosslinking points and density of a polymer cross-linked network structure and suitability for various polymer network structures containing different functional groups. 1. A kind of preparation method of precise polymer network, characterized in that the method comprises the following reaction steps: A) the function of the double bond of the functional group-containing monomer (A), in order to and taking AIBN as initiator, thioester three double functionality Rotating chain transfer agent, three molar ratio of 50 : 0.05: 1-1000 : 0.2: 1, the tail end of the reaction of the functional group of the thioester is provided with three linear polymer (B); B) to N-maleimide As functional monomer, azobisisobutyronitrile is used as an initiator, the step a) preparation of the linear polymer (B) for large molecular chain transfer agent, the molar ratio of the three 2 : 0.01: 1-100 : 1:1, the end of the functional group-containing polymer produced R ' linear polymer (C); C) for the monomer to β-pinene, azobisisobutyronitrile is used as an initiator, said step b) of synthetic polymer (C) for large molecular chain transfer agent, three molar ratio of 2 : 0.01: 1-100 : 1:1, the end of the polymer produced containing β-pinene functional group and R ' functional group of the linear polymer (D); D) to said step c) preparation of a linear polymer (D) for large molecular chain transfer agent, in accordance with steps b) and c) the procedure of method of, again reversible addition-fragmentation chain transfer of free radical polymerization reaction, so repeatedly, each reversible addition-fragmentation chain transfer of free radical polymerization, the above times are reversible addition-fragmentation chain transfer generated in the free radical polymerization reaction of a linear polymer (D) for large molecular chain transfer agent, so as to finally obtain the end-group containing a plurality of R ' functional group of the polymer (E); E) click-chemical: the said step d) the prepared terminal group comprising a plurality of R ' functional group of the polymer (E) with the polymer (F) generating click-chemical reaction, to obtain regular cross-linked network structure, said polymer F) in order to contain the two or more azide, alkynyl or mercat large molecular polymer, its molecular weight is 500-20000. 2. Method of accurately preparing the polymer network according to Claim 1, characterized in that said step a) of the monomer in (A) for N-isopropyl acrylamide, five fluobenzene ethylene, styrene sulfonic acid sodium, styrene and its derivatives, tert-butyl acrylate, methyl methacrylate, methyl acrylic acid two hydroxy ethyl ester , 2-(dimethylamine) ethyl methyl acrylate, acrylonitrile in any one of. 3. Method of accurately preparing the polymer network according to Claim 1, characterized in that said step a) double functionality of the thioester threeThe functional group R different propionate of the ethylene glycol, the ethylene glycol isopropyl ester derivatives or benzene two different propionyls , Z substituent is benzene ring or alkyl, ethylene glycol isopropyl ester derivative is polyethylene glycol isobutyrat, propylene glycol isobutyric acid ester or butanediol isobutyrat. 4. Method of accurately preparing the polymer network according to Claim 1, characterized in that said step b) of in N-maleimide The substituent on R ' is a halogenated hydrocarbon or alkynyl. 5. Method for preparing polymer network accurately as in Claim 1, 2, 3 or Claim 4, characterized in that said step a) of the linear polymer in (B) of molecular weight 1000-60000, molecular weight distribution coefficient of 1.09-1.10. 6. Method for preparing polymer network accurately as in Claim 1, 2, 3 or Claim 4, characterized in that said polymer (E) containing the end of the R ' functional group is through control of the number of the reversible addition-fragmentation chain transfer the number of free-radical polymerization reaction, that is, repeating step c) to step d) the number of times reaches.