Characteristics of polymeric peracids on acrylic acid-grafted polyethylene prepared by photografting in the presence of N, N′-methylenebisacrylamide

Abstract

Photografting ( λ>300 nm, 60°C) of acrylic acid (AA) on low-density polyethylene (PE) film (thickness=30 μm), on which xanthone photoinitiator was coated earlier, was largely accelerated when small amounts of N, N′-methylenebisacrylamide (MBAAm) (0.67 and 3.3 mol% of AA monomer used) were added to the system. The addition of MBAAm did not affect distribution of the grafted chains in the cross section of the resultant AA-grafted PE film, which was measured by electron probe microanalysis. The AA-grafted samples were subjected to peroxidation with hydrogen peroxide in the presence of methanesulfonic acid at 25°C for 3 h to yield polymeric peracids. The amount of peracids formed was smaller for the grafted samples prepared in the system with MBAAm than those prepared in the system without MBAAm. Moreover, thermal decomposition of the polymeric peracids at 40°C was largely retarded for the former samples compared to the latter samples. These results suggest the formation of a cross-linked structure in the AA-grafted chains, which are introduced into PE substrate by photografting in the presence of MBAAm.