Influences of Peeling Rate and Temperature on Tack Properties and Peeling Behavior for Polyacrylic Block Copolymer

Abstract

Influences of peeling rate and temperature on peeling behavior of polyacrylic block copolymer were investigated. For this purpose, poly(methyl methacrylatc)-block-poly(n-butyl acrylate)-block-poly (methyl methacrylate) triblock copolymer (MAM) with hard block contents of 23 (MAM-23) and 16wt% (MAM-16) and 1/1 blend with diblock copolymer consisting of same components(MA) (MAM-23/MA, total hard block content of 15 wt%) were used. The peeling process at the probe/ adhesive interface during the probe tack test was observed using a high-speed microscope at 23℃ with probe rate of 10 mm/s. Three different peeling mechanisms were observed. TypeA: Peeling progressed linearly from the edge to the center of the probe without cavitation (MAM-23). TypeB: Peeling progrossed linearly from the edge to the center of the probe with cavitation (MAM-16). TypeC: Cavitation occurred in the entire adhesive layer, and peeling initiation was delayed (MAM-23/MA). The peeling behavior of MAM-23 changed from Type A to Type B with a decrease of peeling rate (1mm/s) or temperature rising (40℃). There was no change for MAM-16 and MAM-23/MA. Although MAM-16 and MAM-23/MA have similar hard block content, their peeling mechanisms differed greatly. The greater flexibility of the soft blockck chain in the diblock copolymer resulted in improved the interfacial adhesion.