Laboratory of Sustainable Polymers, Department of Analytical Chemistry and Organic Chemistry, University Rovira i Virgili, 43007 Tarragona, Spain.
Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain.
Molecules. 2020 Dec 5;25(23):5740. doi: 10.3390/molecules25235740.
Lactic acid is one of the key biobased chemical building blocks, given its readily availability from sugars through fermentation and facile conversion into a range of important chemical intermediates and polymers. Herein, well-defined rubbery polymers derived from butyl lactate solvent were successfully prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization of the corresponding monomeric acrylic derivative. Good control over molecular weight and molecular weight distribution was achieved in bulk using either monofunctional or bifunctional trithiocarbonate-type chain transfer agents. Subsequently, poly(butyl lactate acrylate), with a relative low (-20 °C), good thermal stability (5% wt. loss at 340 °C) and low toxicity was evaluated as a sustainable middle block in all-acrylic ABA copolymers using isosorbide and vanillin-derived glassy polyacrylates as representative end blocks. Thermal, morphological and mechanical properties of copolymers containing hard segment contents of <20 wt% were evaluated to demonstrate the suitability of rubbery poly(alkyl lactate) building blocks for developing functional sustainable materials. Noteworthy, 180° peel adhesion measurements showed that the synthesized biosourced all-acrylic ABA copolymers possess competitive performance when compared with commercial pressure-sensitive tapes.
乳酸是一种关键的生物基化学结构单元，因为它可以很容易地从糖通过发酵获得，并且很容易转化为一系列重要的化学中间体和聚合物。在此，通过相应的单体丙烯酸衍生物的可逆加成-断裂链转移（RAFT）聚合，成功地从丁基乳酸溶剂中制备了结构明确的橡胶状聚合物。使用单官能或双官能三硫代碳酸酯型链转移剂在本体中可以很好地控制分子量和分子量分布。随后，聚（丁基乳酸丙烯酸酯）（相对低的玻璃化转变温度（-20°C）、良好的热稳定性（在 340°C 时 5%重量损失）和低毒性）被评估为使用异山梨醇和香草醛衍生的玻璃状聚丙烯酸酯作为代表性端基的全丙烯酸酯 ABA 嵌段共聚物中的可持续性中间嵌段。共聚物的热、形态和力学性能进行了评估，以证明橡胶状聚（烷基乳酸酯）结构单元在开发功能性可持续材料方面的适用性。值得注意的是，180°剥离附着力测量表明，与商业压敏胶带相比，合成的生物源全丙烯酸酯 ABA 嵌段共聚物具有竞争力。
