Sequence Regulation Based On Dynamic Covalent Bond Of Furan/Maleimide

The sequence regulation of monomer units plays an important role in biology and is an significant feature of life,such as replication,transcription and translation of DNA.The sequence structure of an organism determines its function,and the specific expression of the function further promotes the biological diversity.Inspired by this,it has become an important research direction to develop efficient means of sequence regulation in polymer chemistryMy dissertation introduces a novel sequence regulation method based on dynamic covalent bond of furan/maleimide,which lays a foundation for the further development of sequence regulation.The research content of this thesis mainly includes the following two aspects:(1)In order to enrich the diversity of sequence regulation modes and fully combines the characteristics of dynamic covalent bond of furan/maleimide,based on the latent monomer strategy,a stereoisomeric latent monomer strategy was proposed and the polymerization conditions and kinetic behavior were preliminarily explored.(2)Furthermore,we further improved the methodology of the strategy of stereoisomeric latent monomer.According to the thermodynamic stability difference of stereoisomeric latent monomer,the variable temperature gradient is designed reasonably.By finely tuning the polymerization temperature,two kinds of stereoisomeric latent monomer were selectively deprotected and copolymerized with St.A variety of sequence controlled polymers with gradient,block and random profile were synthesized.The idiographic works are as follows:(1)Firstly,two kinds of stereoisomeric furan/maleimide adducts,endo-FMI and exo-FHMI,were synthesized and named stereoisomeric latent monomer.Secondly,the deprotection kinetics of two stereoisomeric latent monomers at different temperatures were studied.Finally,binary copolymerization experiments involving two stereoisomeric latent monomers,endo-FMI and exo-FHMI,were designed and their polymerization kinetics were investigated in detail.(2)By virtue of the big gap of deprotection temperature of exo-and endo-latent monomers,more diversified sequence-controlled polymers could be on-demand created via one-shot feeding of comonomers at the beginning.Firstly,the kinetics of controlled ternary copolymerization involving only one stereoisomeric latent monomer was studied,and the sequence controlled terpolymers consist of St/MI/PMI were synthesized successfully.Secondly,the kinetics of controlled ternary copolymerization involving two stereoisomeric latent monomers was studied,and the sequence controlled terpolymers consist of St/MI/HMI were synthesized successfully.Finally,the kinetics of the controlled quaternary copolymerization involving two stereoisomeric latent monomers was studied,and the sequence controlled quadripolymers consist of St/MI/HMI/PMI were synthesized successfully.We further analyzed the effects of the functional groups content of maleimide derivatives and the sequence structure on the thermal properties of sequence controlled polymers.Importantly,the sequence structures could be pre-designed by multi factors including temperature change mode,polymerization time at each temperature slot and feed ratio of the co-monomers.This work enriches latent monomer strategy by using stereoisomeric furan/maleimide adducts,and would greatly diversify sequence structures with more monomers and advanced functionalities and lay the foundation for the performance development of new polymer materials.