No abstract

A method for the development of ABA triblock copolymers for high-performance pressure-sensitive adhesives from the biorenewable chemicals lauryl acrylate and triacetic acid lactone (TAL) is presented. Lauryl acrylate, readily derived from vegetable oils, was polymerized via a reversible addition− fragmentation chain-transfer process to yield high-molecularweight telechelic polymers. The synthesis of triblock copolymers was accomplished by subsequent chain extension with TAL, which is available from carbohydrates via the action of genetically modified yeast. The resulting triblock copolymers were found to exhibit excellent adhesion, with tunable peel forces up to 8 N cm −1 when a rosin ester-based tackifier was used. Tack forces up to 7 N cm −1 and no shear failure up to 100 h demonstrate the competitive performance of the potentially sustainable adhesives with commercial commodity products.

The solid state and fluxional behaviors in solution of complexes L2AlOBn and L7AlOBn (Bn = benzyl) supported by an analog of salen incorporating indolide arms connected via their 2- and 7-positions were defined by experiment and theory. The complexes catalyze the stereoselective conversion of rac-lactide (rac-LA) to isotactically enriched polylactide. A key aspect of the stereocontrol was examined through study of the initiation reactions via NMR spectroscopy, X-ray crystal structures of the ring-opened products, and theory. The results include the first unambiguous structural definition of stereocontrol in ring-opening of LA by a metal–alkoxide complex and the finding that definition of the stereochemistry of initiation by the studied system is governed thermodynamically rather than kinetically.

Tunable and degradable crosslinked-polyanhydride networks from renewably derived itaconic anhydrides and multifunctional thiols have been developed.