Preparation And Properties Of Crosslinked Polymers Based On The Condensation Reaction Between ?-diketone And Primary Amines

The condensation reaction between ?-diketone and primary amines can produce ?-ketoimine structure.This kind of reaction shows high efficiency in mild conditions and can be involved in various functional raw materials andusually used in molecular design.Besides,it's also widely used in the field of polymer material modification and enhancement and has broad application prospects.In this text,we will do research on the following two routes.(1)A series of copolymers with ?-diketone groups(xBA-AAEM)were synthesized with N-butyl acrylate(BA)and 2-(Acetoacetyloxy)Ethyl Methacrylate(AAEM)copolymerized.The adjacent dihydroxyl groups were attached to the copolymers via the reaction between ?-diketone and primary amines.With boric acid as the crosslinking agent,a series of crosslinked polymers were obtained via boron esterification.?-ketoimine also coordinated with metal ions to form the third crosslinking network.The mechanical properties of copolymers samples and the influence factors were studied by tensile measurements and dynamic mechanical tests.Significant impacts on the mechanical performances included the compositions of copolymer,the content of adjacent dihydroxyl and crosslinking density.The presence of dihydroxyl groups can not only effectively improve the mechanical properties via the hydrogen bonds among copolymers,but also provide the channels for absorption of boric acid into the polymer network to form crosslinked inorganic-organic hybrid via boron esterification bonds.As a result,a low content of boron(around 1 wt%)can further improve the mechanical properties,which is very similar to the mineralization function of mineral elements in plants.Inspired by the phenomenon in nature,we can effectively tailor the mechanical properties of copolymer changing from flexibility to rigidity via controlling the content of hydroxyl groups and its reaction with boric acid.Furthermore,the boron ester bond can be reversed in acid and base solution,and various shape configurations could be realized via controlling the pH levels of the environment.(2)Terephthalaldehyde were used to react with D400 based on Schiff base reaction to synthesize amine-terminated diamine crosslinkers of different segment lengths according to three different feed ratios.These cross-linking agents were added to different proportions of the acrylate copolymer(xBA-AAEM)synthesized in route(1)to synthesize a series of cross-linked polymers.The occurrence of cross-linking reactions was characterized by FT-IR and NMR spectra.The swelling property of polymers could be effectively affected by adjusting the structure and the amount of crosslinking agents.The results of tensile test and dynamic thermomechanical analysis showed that the mechanical properties of crosslinked polymers with different molecular structure and crosslinking density changed regularly.