Polyhydroxyurethane(PHU)have received more and more attention from researchers as a green polymer material.However,the low reaction rate between cyclic carbonate and amine for the synthesis of PHU leads to incomplete reaction,e.g.,low relative molecular mass and poor chemical and physical properties,which greatly limits the mechanical properties of PHU.Therefore,in this paper,a series of multifunctional PHU-based polymers were synthesized mainly to improve the mechanical properties(fracture stress,toughness)of PHU.First,high-strength multifunctional PHU was synthesized through the construction of molecular structures.Secondly,epoxy was introduced into the synthesis of PHU to improve the reaction rate of PHU.Finally,highly tough,multifunctional polymers of polyhydroxyurethane and epoxides were synthesized through the construction of molecular structures.The research of this thesis is as follows:(1)A high-strength multifunctional PHU material was prepared by using thiol,cyclic carbonate,and amine.Initially,the"click reaction"between thiol and alkene was used to design the molecular structure of PHU(with different numbers of cyclic carbonate monomers).Besides,the PHU exhibited excellent shape memory properties(the material was recycled three times with shape memory,and the shape fixation and recovery rates were greater than 80%),recyclable properties(the shape memory properties of the reprocessed material are superior to those of the original material),and damage self-reporting properties.(2)Due to the low reaction rate,the conversion of cyclic carbonate to PHU with amine under solvent-free,atmospheric pressure conditions is almost incomplete.To solve the above problem,epoxy(EP)was introduced into the PHU system as a highly reactive functional group to promote the complete reaction of cyclic carbonate with amine.The introduction of EP has greatly improved the mechanical properties and chemical physical stability of PHU(excellent solvent resistance properties).The prepared bio-based PHU-EP hybrid has shape memory properties,damage self-reporting properties,and high glass transition temperature(Tg>100℃).(3)Based on the second work,PHU-EP with higher toughness(15.6 MJ/m3)was successfully prepared by adjusting the microscopic molecular structure,and then a large amount of Fe3O4(10 wt%、20 wt%、30 wt%)was introduced to synthesize a photo-thermal dual-trigger shape memory composite.The films without Fe3O4 exhibit excellent mechanical properties and light transmission.The composites containing Fe3O4 have excellent light absorption(>93%)and thermal conductivity,which facilitates the remote tuning of the material shape. |