Polymers that degrade on demand have the potential to facilitate chemical recycling, reduce environmental pollution and are useful in implant immolation, drug delivery or as adhesives that debond on demand. However, polymers made by radical polymerization, which feature all carbon-bond backbones and constitute the most important class of polymers, have proven difficult to render degradable. Here we report cyclobutene-based monomers that can be co-polymerized with conventional monomers and impart the resulting polymers with mechanically triggered degradability. The cyclobutene residues act as mechanophores and can undergo a mechanically triggered ring-opening reaction, which causes a rearrangement that renders the polymer chains cleavable by hydrolysis under basic conditions. These cyclobutene-based monomers are broadly applicable in free radical and controlled radical polymerizations, introduce functional groups into the backbone of polymers and allow the mechanically gated degradation of high-molecular-weight materials or cross-linked polymer networks into low-molecular-weight species.

按需降解的聚合物有可能促进化学回收、减少环境污染，并可用于植入物自焚、药物输送或用作按需脱粘的粘合剂。然而，通过自由基聚合制成的聚合物具有所有碳键主链并构成最重要的一类聚合物，已被证明很难使其可降解。在这里，我们报道了基于环丁烯的单体，它可以与常规单体共聚，并赋予所得聚合物机械触发的降解性。环丁烯残基充当机械载体，可以进行机械触发的开环反应，从而导致重排，使聚合物链在碱性条件下通过水解而裂解。这些环丁烯基单体广泛适用于自由基和受控自由基聚合，将官能团引入聚合物主链中，并允许高分子量材料或交联聚合物网络机械门控降解为低分子量物质。