Synthesis Research Of Acrylic Sustainable Polymer Materials

Synthetic polymer materials are the most important materials in modern society,providing great convenient and dramatic changes for human world.However,the current production and disposal mode of polymer materials is seriously unsustainable.On the one hand,the current synthetic polymer materials are mainly derived from non-renewable fossil resources,which produces conspicuous contradiction between the shortage of raw materials and the increase in demand.On the other hand,most synthetic polymer materials are undegradable,thus the massive use of synthetic polymer materials will cause serious environmental consequences.Therefore,the development of new sustainable polymer materials by replacing the current linear production mode with a circular material economy to realize the sustainable development of polymer materials is urgently needed.As one of the avenues towards sustainable polymer materials development,chemical recycling which includes the establishment of a polymerization-depolymerization cycle and upcycling,meets the requirements of circular material economy.Biomass-derived?-methylene-?-butyrolactone(MBL)is a cyclic analogue of methyl methacrylate(MMA),whose polymer is generally regarded as an alternative of petroleum-based commodity poly(methyl methacrylate)(PMMA).However,the synthesis of MBL monomer is tedious,and its polymer poly(?-methylene-?-butyrolactone)(PMBL)cannot get practical applications due to its brittleness.To addressing these issues,this article uses various cheap and easily available biomass-derived aldehydes(heptanal,cinnamaldehyde,citronellal,perillaldehyde),innovatively synthesized four new types of biomass monomers based on the MBL skeleton through a one-step allylation/lactonization reaction with up to 84.5%yield.Structures such as flexible long chain,double bonds and benzene could be successfully introduced into the MBL five-membered ring skeleton,laying a foundation for subsequent functional modification for properties improvement.We found that the utilization of sterically encumberedandstrongLewis-acidicbis(2,6-di-tert-butyl-4-methylphenoxy)(methyl)aluminum[Al Me(BHT)₂]and 1,3-diisopropyl-4,5-dimethylimidazole-2-ylide(IⁱPr)as a Lewis Pair(LP)catalyst system could realize the control polymerization efficiently,giving the polymers with M_n up to 210.5 kg/mol and molecular weight distribution between 1.03-1.54.In addition,the polymer has a wide range of adjustable glass transition temperature(T_g=84oC-206oC),and the double bond-containing polymer has been successfully post-functionalized through the thiol-ene click reaction.More importantly,the polymer can be thermally depolymerized quickly and efficiently within 60 minutes with the monomer recovery rate up to 99.8%,It can be seen that we have established a polymerization-depolymerization cycle,and successfully prepared a new type of sustainable acrylic polymer material.Isotactic poly(trityl methacrylate)(PTr MA)is often used as a filler for HPLC chiral columns due to its chiral environment and excellent solvent resistance.High molecular weight PTr MA is insoluble in common organic solvents,so it is difficult to recycle.Next,an efficient post-polymerization modification is used to realize the upcycling of isotactic PTr MA in this paper.Controlling the reaction conditions,isotactic PTr MA can be completely hydrolyzed into isotactic poly(methacrylic acid)(PMAA)and trityl alcohol within 30 minutes without the side reaction of methyl esterification.The recovered trityl alcohol can be reused to prepare monomers to achieve a closed loop cycle.The isotactic PMAA can be post-polymerization modificated by tetramethylguanidine catalyzed high-efficiency esterification reaction and1H-benzotriazol-1-yloxytripyrrolidinylhexafluorophosphate/1-hydroxybenzotriazole catalyzed amidation reaction,and a series of isotactic polymethacrylates and polymethacrylamide were obtained,realizing the upcycling of PTrMA.