Studies On Graft Of Photoiniator Monomer On Surface Of Polymer Film

Attachment of macromolecules to surface of polymer using photografting methord is an special approach to make the material have some important physiological functions. Multifunctional photoinitiators are able to induce graft polymerization on the surface as well as functionally modify the surface, which provide a new way for the functional modification of surface.Polymerizable benzophenone(BP) photoinitiator 4-benzophenone methacrylate (BPMA) and 4,4'-dimethacrylate benzophenone (DBPMA) were used in this article,which contains the BP group as well as produce chain polymer through free radical polymerization of themself. The benefits of these photoinitiator monomer used in photografting system are: 1. The BP group produces surface free radicals to induce graft polymerization; 2. Initiator monomer itself can be polygrafted to modify the surface, which can bring more BP moiety; 3. Functional macromolecules can be attached onto surface by the photochemical reaction of BP units of Polymer chains.To explore the surface photoinitiator monomer grafting system, two methods were designed to modified membrane surface using BPMA and DMABP.For less Consumption of the BP units of monomer, two-step photografting polymerization of photoactive monomer were using, in which semipinacol groups were coupled on the surface in the first step, and then cleaved to generate macro-radicals on surface to begin the grafting polymerization via heating in the second step. The BP group of monomer did not participate in this polymerization to got maximum retention.For making the experimental simple and easily controlled, BPMA and DMABP were polygrafted onto the surface of polypropylene film (PP) under UV by a one-step photografting polymerization iniated by benzophenone (BP) moieties of themselves that the photoactive monomer were used as both iniator and monomer.Furthermore, For both one-step and two-step methord above, typical hydrophobic polystyrene, hydrophilic polyethylene glycol (PEG) and Bovine serum albumin (BSA) were attached onto surface by the photochemical reaction of BP units, resulting in a greater hydrophobic or hydrophilic surface.