Study On Synthesis And Properties Of Environmentally Sensitive Polymer Materials

Environmentally-sensitive polymer is one of the most widely studied polymer materials at present because of its sensitivity to environment and reaction ability,and has a good development prospect in environmental protection,medical treatment,engineering and many other fields.Among the environmentally-sensitive polymers,multi-sensitive polymers have attracted much attention because of their excellent multi-responsiveness.At present,polymer pollution and excessive demand for natural resources lead to serious environmental problems.Repeatability and effective recovery of materials are an important means to solve the current environmental pollution.Therefore,it is of great significance to prepare polymer materials with multiple sensitivities or polymer materials that can realize green recycling.In this paper,environmentally-sensitive polymers were prepared by living radical polymerization and click chemistry.The living radical polymerization uses reversible addition and fragmentation chain transfer radical polymerization(RAFT).The RAFT method has many advantages,such as convenient preparation and low price of materials.However,it is a challenge to select suitable RAFT reagents for monomers with different activities.As a reversible chemical reaction,Diels-Alder(DA)reaction of click chemistry has been widely used in the synthesis of recyclable materials.However,the curing temperature of some materials limits its specific application,and the recovery temperature and method are a challenge.Therefore,preparing a temperature sensitive recyclable material can provide the necessary theoretical basis for the practical application of environment friendly polymers.Therefore,in this paper,a block polymer PDMAEMA-b-PVP-CTA-PVP-b-PDMAEMA with multiple sensitivities was synthesized by RAFT polymerization,and then a recyclable polymer material PEGFA/PPGFA/BMI with self-repairing property was prepared by thermoreversible DA reaction without by-products.Both materials are stimulus-responsive materials.The former pays more attention to sensitivity in aqueous solution,while the latter pays more attention to reversible recoverability.In the synthesis of block polymer PDMAEMA-b-PVP-CTA-PVP-b-PDMAEMA,we first synthesized small molecular CTA by "step by step" method and "one-pot" method,and then synthesized large molecular CTA with different arm lengths by adjusting the arm length of macro-CTA by adjusting n(NVP)/n(CTA).The ratio of n(PDMAEMA)/n(CTA)was adjusted to control the polymer of PDMAEM,and PDMAEMA with different polymerization degrees was synthesized.Furthermore,block polymer was synthesized by RAFT polymerization,and the synthesis process of polymer was analyzed in detail by infrared,nuclear magnetic resonance and GPC.In addition,through the study of p H and temperature sensitivity of polymer,it could be concluded that the ionization degree of polymer in tumor is between 86.32% and 99.50%,which proves the potential application of polymer in medical treatment.In the synthesis of polymer material PEGFA/PPGFA/BMI,the long chain PEGFA of polyethylene glycol diglycidyl ether with furan structure was obtained by amino epoxy group addition reaction of furan methylamine and polyethylene glycol diglycidyl ether(PEGDGE),and the long chain PPGFA of polypropylene glycol diglycidyl ether was obtained by reaction of furan methylamine with PPGDGE,and then N,N'-4,4'-diphenylmethane bismaleimide(BMI)was used as curing agent,various polymers with different component ratios were synthesized.We synthesized polymers at different temperatures and analyzed their polymerization kinetics,and discussed the thermodynamic and mechanical properties of polymer materials in detail.The results show that polymer materials could be cured at room temperature,and the curing rate was fast,and its conversion rate was as high as 95%;The polymer materials had regular swelling properties,and the change of material composition and BMI content could affect the swelling properties of materials At about 100 ?,the material will react reversely.At the same time,the "green solvent" ethanol was used as solvent for material recovery,after material recovery and preparation,the mechanical properties hardly change.The polymer material has good application potential in reversible application field.