聚氨基酸接枝聚异戊二烯的仿生合成与性能

Biomimetic Synthesis and Properties of Polyisoprene-based Rubber Grafted with Poly(amino acid)

通过硫醇-烯点击反应将2-氨基乙硫醇接枝到聚异戊二烯主链上合成带有氨基侧链的聚异戊二烯,再通过侧链氨基引发L-缬氨酸-N-硫代羧基内酸酐(Val-NTA)单体和β-苯丙氨酸-N-硫代羧基内酸酐(β-Phe-NTA)单体的聚合,制备出2种方式改性的聚异戊二烯.其中,Val-NTA聚合接枝聚异戊二烯的拉伸强度28.6 MPa,300%定伸强度18.9 MPa,相比天然橡胶分别提升10.7%和9.3%.β-Phe-NTA聚合接枝聚异戊二烯的拉伸强度28.0 MPa,比天然橡胶提升8.3%.

During the recent decades,the endogenous biocomponents contained within natural rubber,such as proteins and phospholipids,are believed to be the causation of its superior properties.A significant amount of work has focused on increasing crosslink density rather than introducing biobased groups.Inspired by the unique properties of natural rubber,one way to improve the performance of synthetic polyisoprene should tune to polyamino acid functionalization.In this work,one kind of high molecular weight polyisoprene,PI-NH_(2),with amino side chains was prepared by grafting 2-Amino-1-ethanethiol via a thiol-ene click reaction.Then,PI-NH_(2) as initiators with two kinds of NTA,which were highly active polyamino acid monomers,were utilized in the preparation of two kinds of poly(amino acid)grafted biomimetic synthetic polyisoprene PI-Vals,PI-β-Phes via amino side chains which demonstrates the efficiency and feasibility of this approach.Among them,the tensile strength of PI-Vals can reach 28.6 MPa,and the stress at 300%is 18.9 MPa,which is 10.7%and 9.3%higher than that of SCR20 natural rubber respectively,the tensile strength of PI-β-Phes can reach 28.0 MPa,8.3%higher than that of SCR20 natural rubber.The dynamic mechanical properties of PI-Vals are characterized by DMA tests,and the loss factor decreases and the energy storage modulus increases compared to those of NR and PI,reflecting a lower hysteresis loss,combined with a significant reduction in heat generation by compression,demonstrating a significant enhancement in dynamic heat generation performance.In addition,this modified preparation strategy for synthetic rubber holds promise for enhancing its range of applications and could serve as an alternative to high-performance rubber with the scarce resources of natural rubber.