We report the organotellurium-mediated living radical polymerization (TERP) using diphenylditelluride (DT-Ph) and di-n-butylditelluride (DT-Bu) in the presence of a binary azo initiator system consisting of 2,2′-azobis(isobutyronitrile) (AIBN) and 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (AMVN) with different decomposition rates for the facile synthesis of high-molecular-weight block copolymers containing a polar side group. The block copolymers containing the poly(tert-butyl acrylate) (PtBA) sequence as the reactive segment and the random copolymer sequences of n-butyl acrylate (nBA) or 2-ethylhexyl acrylate (2EHA) with 2-hydroxyethyl acrylate (HEA) as the adhesive segment were synthesized. The concurrent use of the binary initiators was revealed to effectively increase both the polymerization reactivity and the molecular weight of the polymers along with a narrow molecular weight distribution. The produced block copolymers exhibited high performance for the dismantlable adhesion responsible for the dual external stimuli consisting of photoirradiation and postbaking in the presence of a photoacid generator.

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High-molecular-weight and functional acrylic block copolymers containing both the reactive and polar repeating units were synthesized using organotellurium-mediated living radical polymerization (TERP) technique. The block copolymers consisted of poly(tert-butyl acrylate) as the reactive segment and the random copolymer sequence containing n-butyl, 2-ethylhexyl, and 2-hydroxyethyl acrylate repeating units as the adhesive segment. The block copolymers exhibited high performance for the dismantlable adhesion responsible to dual external stimuli consisting of photoirradiation and the postbaking in the presence of a photo acid generator.

The acrylic copolymers involving 2-hydroxyethyl acrylate (HEA) and tertbutyl acrylate (tBA) units as reactive units behave as pressure-sensitive adhesive type dismantlable adhesive materials. In order to clarify the individual role of HEA and tBA units on dismantlability, the 180° peel behavior after the dismantling treatment, i.e., heating in the presence of given amount of acid catalysts, was systematically investigated using the acrylic copolymers involving different amounts of the reactive units. It was revealed that transesterification of HEA units resulted in an increase in the cohesive force and modulus due to an increase in the molecular weight and cross-linking. Deprotection of tBA units, i.e, transformation of tBA to acrylic acid unit with isobutene evolution, promoted cross-linking by the esterification of acrylic acid units and tended to reduce a cohesive force by forming voids in the adhesive layer due to the evolution of isobutene gas. Interfacial failure in the peel tests corresponded with a high degree of cross-linking and increased modulus of the adhesive.Conversely, cohesive failure was associated with reduced cohesive strength of the adhesive layer and a low peel strength.

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