Abstract：
Pressure-sensitive adhesives (PSAs) are made from soft, irreversibly lightly crosslinked polymers. Even after removal from surfaces, they retain insoluble networks which pose problems during the recycling of glass and cardboard. Herein, degradable PSAs are presented that provide the required performance in use but have networks that can be degraded after use. A series of copolymers was prepared through radical copolymerization of n-butyl acrylate, 4-acryloyloxy benzophenone (ABP) photo-crosslinker, and dibenzo[c,e]oxepin-5(7H)-thione (DOT) to provide degradable backbone thioesters. The optimum tack and peel strengths were found for molar contents of 0.05 mol% ABP and 0.25 mol% DOT. Degradation of the backbone thioesters through aminolysis or thiolysis led to the full dissolution of the networks, loss of adhesive properties of films (decreases in the measured tack and peel strengths), and the quick detachment of model labels from a substrate. Inclusion of DOT into PSAs offers a viable route toward degradable and recyclable packaging labels.
摘要：
压敏粘合剂（PSA）由柔软，不可逆轻度交联的聚合物。即使在从表面移除后，它们保留了不溶性网络，这在玻璃和纸板的回收过程中会带来问题。在这里，提出了可降解的PSA,其在使用中提供所需的性能,但具有在使用后可以降解的网络。通过丙烯酸正丁酯的自由基共聚制备了一系列共聚物，4-丙烯酰氧基二苯甲酮(ABP)光交联剂,和二苯并[c，e]oxepin-5（7H）-硫酮（DOT）以提供可降解的主链硫酯。对于摩尔含量为0.05mol％的ABP和0.25mol％的DOT，发现了最佳的粘性和剥离强度。通过氨解或硫解降解主链硫酯导致网络完全溶解，薄膜粘合性能的损失（测量的粘性和剥离强度降低），以及模型标签从基板上的快速分离。将DOT纳入PSA为可降解和可回收的包装标签提供了可行的途径。
