Dismantlable adhesion properties of reactive acrylic copolymers resulting from cross-linking and gas evolution

Abstract

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.

Design of a High-Performance Dismantlable Adhesion System Using Pressure-Sensitive Adhesive Copolymers of 2-Hydroxyethyl Acrylate Protected with tert-Butoxycarbonyl Group in the Presence of Cross-Linker and Lewis Acid

“…It was previously pointed out that the bubble formation in the adhesive layer tended to induce cohesive failure rather than interfacial failure during the dismantling process of the other pressure-sensitive adhesive system. 63…”

Control of adhesive strength of acrylate polymers containing 1-isobutoxyethyl and isobornyl esters in response to dual stimuli for dismantlable adhesion

“…The interactions at the SUS/ adhesive and PET/adhesive interfaces competed with each other and determined the failure mode, but the both interactions seemed to be weak and finally the isolation of the adhesive layers was often observed. In fact, it was considered that the transesterification and/or esterification of the HEA unit took place with the deprotection of the iBEA unit in the presence of an acid catalyst causing cross-linking [24]. In the previous study, the adhesive layer stuck on the PET film was easily peeled off and consequently the crosslinked adhesive layer was removed from both the SUS and PET without any adhesive deposit [25].…”

“…We previously reported a dismantlable adhesive system using degradable polyperoxides as curable and pressure-sensitive adhesives and the control of bonding strength by the radical chain degradation of the polyperoxide adhesives [16][17][18]. More recently, we developed an advanced system using acrylic polymers containing t-butyl acrylate (tBA) unit in order to overcome the dilemma of reliable adhesion property during use and the subsequent quick debonding [19][20][21][22][23][24]. The tBA-containing polymers were demonstrated to function as the dismantlable adhesive materials due to a facile transformation to polymers including acrylic acid repeating units, accompanied by the elimination of isobutene gas, under the appropriate photo irradiation conditions followed by postbaking at a desired temperature.…”

Research on Kinematics and Stability of a Bionic Wall-Climbing Hexapod Robot

“…At present, the main adhesive methods of wall-climbing robot include magnetic adhesion [6], adhesion of adhesive materials [7, 8], and vacuum adhesion [9]. The motion mechanism of robot mainly includes legged type [10, 11], crawler type [12], and frame type [13].…”