Synthesis And Properties Of Amphiphilic Grafted Polymers Based On

Graft polymers consist of macromolecular main chain and side chain which are incompatible with each other. In recent years, graft polymers have attracted much attention because of its special physical and chemical properties, attributing to the different polymer chains of main chain and side chains.In this article, two kinds of amphiphilic graft polymers were synthesized by combining living polymerization with coupling reaction, which will be described in details as follows:(1)3-[(allyloxy)meth-yl]-3-ethyl-1,5-pentanediol and DPMK were employed as initiator and coinitiator, respectively. PEO-Allyl-PEO with an allyl group in the middle chain was synthesized via living ring opening polymerization. Then PEO-Allyl-PEO coupled with each other by Williamson reaction to obtain the high molecular weight PEO [(PEO-Allyl-PEO)S], which has many allyl groups on the chain. By thiol-ene reaction, every allyl group was modified into two hydroxy groups, which were employed as initiated sites to synthesize PCL side chains by ROP. So the amphiphilic graft polymer PEO-g-PCL2was obtained with hydrophilic PEO as backbone and hydrophobic PCL as side chains. Finally, both the target products and intermediates were well-defined by SEC and JH NMR. Also, the crystallization behaviors were characterized by WAXD, DSC and POM.(2)The initiator4-(2,3-dihydroxypropoxy)-2,2,6,6-tetramethylpiperidine-1-o-y1(DHP-TEMPO) was firstly synthesized with one TEMPO group. Using DHP-TEMPO as the initiator and DPMK as the coinitiator, linear PEO-TEMPO-PEO was synthesized by living ring opening polymerization. Then PEO-TEMPO-PEO coupled with each other in DCM by Williamson reaction to obtain the high molecular weight PEO [(PEO-TEMPO-PEO)m], which has many TEMPO groups on the chain. Then, the polystyrene with bromide on the end was synthesized by atom transfer radical polymerization (ATRP). Finally, the amphiphilic graft polymer PEO-g-PS was obtained by (PEO-TEMPO-PEO)m coupling with PS-Br via ATNRC reaction. The PEO-g-PS was hydrolyzed in2M HC1solution. Both the target products and intermediates were well-defined by SEC and1H NMR.