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.