Preparation and Characterization of a Renewable Pressure-Sensitive Adhesive System Derived from ε-Decalactone, <scp>l</scp>-Lactide, Epoxidized Soybean Oil, and Rosin Ester

Abstract

Pressure-sensitive adhesives (PSAs) are prepared with plant-based thermoplastic polyester elastomers (TPPEs), rosin ester tackifier, and epoxidized soybean oil plasticizer. Controlled bulk ring-opening transesterification polymerization of ε-decalactone and l-lactide using diethylene glycol as an initiator gives ABA type block polyesters via a one-pot, two-step process with only tin(II) ethylhexanoate. Three semicrystalline poly(l-lactide)–poly(ε-decalactone)–poly(l-lactide) (PLLA–PDL–PLLA) triblock copolymers are prepared containing 100 kg mol–1 PDL midblocks and 8–30 wt % PLLA end blocks with narrow dispersities. The mechanical behavior of the triblock architectures is investigated by tensile experiments. The triblocks are combined with the tackifier of 50 wt % and the plasticizer of 15–30 wt %. The thermal, viscoelastic, and morphological properties of the elastomers and the adhesive formulations are determined with differential scanning calorimetry, thermal gravimetric analysis, dynamic mechanical analysis, and atomic force microscopy. The renewable self-adhesive performance is evaluated showing peel strength of 1.9–2.6 N cm–1, probe tack of 2.2–3.0 N, and static shear strength of >20 000 min comparable to current thermoplastic elastomers and PSAs. These novel materials could hold promise for sustainability and high adhesive performance.