New manufacturing processes for block and graft copolymers by radical reactions and their applications

Abstract

New industrial manufacturing processes to obtain block and graft copo l ymers were developed by using special organic peroxides. Synthetic scheme is shown in Scheme 1. Step (1)shows the process to obtain block copolymers. In this process, polymeric peroxides (PPO)which have several 0-0 bonds in a molecule are used. Polymeric peroxides excelling in safety and solubility were newly prepared. One of them, for example, is [C(O)C4H8C(O)-(OC2H4)3-OC(O)C4H8C(O)-O-O-tBu] First monomer is polymerized with PPO to provide PM1 having 0-0 bonds. Second monomer is polymerized with PM1 having 0-0 bo nds to get PM, -b-PM2 as shown in step(1). Step(2) in scheme 1 shows the process to obtain graft copolymers. A monomer having an 0-0 bond [e. g. CH2=CHCH20C(0)-0-0-tBu] is copolymerized with M1 and conventional initiator at a temperature below the decomposition temperature (about 100 °C) of the 0-0 bond and PM1 having pendant 0-0 bonds is obtained. Second monomer is addition-polymerized to the pendant 0-0 bonds to get PM1-b-PM2. Polymerization results were shown in Table 1. (I) +R-0-0 10M I P M, 0-0 PM, M 2 P M 1 P M, POLYMERIC PEROXIDE (2) C C M1 PM, Mz pm, =0-0-R PMz PEROXIDE MONOMER (3) Polyolofin Poloyl fin Extruder P M, Scheme 1 Synthetic scheme of block and graftcopolymers with polymeric peroxides and peroxide m o n o m e r s Table 1 Block and graft copolymerizatio n Monomer (1/1 wt) Polym e r p r o d ucts (wt%)V A c/St PVAc-b-PS, 84 PVAc, 6, PS, 10MMA/St PMMA-g-PS, 44 PMMA, 33, PS, 23 Vinyl polymers having pendant 0-0 bonds are thermally mixed in an extruder with polyolefins and Polyolefin-g-Vinylpolymer is obtained by the reactive-processing in which grafting efficiency is about 50%. Some applications, such as surface modification, polymer c ompatibilization and impact modification with block and graft copolymers were studied. © 1992, The Chemical Society of Japan. All rights reserved.