Impact of Degradable Linkages on the Crystallization Behaviors of Polyethylene Mimics.

Incorporating degradable linkages into polyolefin backbones offers a promising route toward sustainable alternatives. For semicrystalline degradable polyolefins, understanding the impact of such linkages on their crystallization behaviors is important, since the crystallization process governs their morphology formation and thus dictates mechanical and thermal performance. Here, we studied the crystallization behaviors of degradable polyethylene (PE) mimics containing sparsely inserted ester linkages along the polymer backbone, which exhibit comparable mechanical and thermal properties to conventional PE. Two systems, HDPE-DM and LLDPE-DM, were investigated and compared with their commercial, non-degradable counterparts under isothermal and non-isothermal conditions. We found that ester incorporation does not alter the thermodynamics of the perfect crystal. However, relative to the non-degradable PE mimics (HDPE-M), the presence of ester linkages accelerates crystallization kinetics by reducing the overall crystallization activation energy and promoting chain folding. The crystallization activation energy of HDPE-DM was comparable to that of commercial HDPE, indicating that ester linkages can be introduced in polymer backbones without significantly impacting their crystallization behaviors and thus relevant industrial manufacturing processes. These findings provide new insights into how degradable linkages influence crystallization in degradable PE materials, which may inform the design and process of sustainable polyolefin materials with a balanced performance and recyclability.