Due to mechanical α-relaxation process, olefin block copolymer (OBC) has a limited heat resistance and thermo-mechanical property. In this work, peroxide-induced melt crosslinking was conducted to fabricate OBC elastomers with two types of crosslinks. It was found that orthogonal crystal structure forms in these chemically crosslinked elastomers. Interestingly, the crystallization peak temperature (T_c,p) shifted to higher temperature after crosslinking, which is mainly due to the crystallization mode transition from confined crystallization to breakout crystallization. Based on CPMG method of LF-¹H NMR and AFM nanomechanics, it was demonstrated that loosely crosslinked OBC achieves double crosslinks of one chemical crosslink and another well-interconnected crystalline crosslink. As a consequence, OBC elastomer with double crosslinks shows an obviously enhanced Young's modulus (∼13.5 MPa), improved high-temperature mechanical properties (∼2.2 MPa strength and ∼220% elongation at break @80 °C) and good damping property (tan δ = 0.42). Furthermore, a balanced reprocessability and elastic recovery can be reached by adjusting the quantity of chemical crosslinks. Therefore, our work can provide guidelines for structural design and related elasticity mechanisms for high performance thermoplastic polyolefin elastomer.

由于机械α-弛豫过程，烯烃嵌段共聚物（OBC）具有有限的耐热性和热机械性能。在这项工作中，进行过氧化物诱导的熔融交联以制造具有两种交联的 OBC 弹性体。发现在这些化学交联的弹性体中形成正交晶体结构。有趣的是，交联后结晶峰温度（T _c，p）向更高的温度移动，这主要是由于结晶模式从限制结晶转变为爆发结晶。^{基于LF- 1}的CPMG方法H NMR和AFM纳米力学表明，松散交联的OBC实现了一种化学交联和另一种良好互连的结晶交联的双交联。因此，具有双交联键的 OBC 弹性体表现出明显提高的杨氏模量（~13.5 MPa）、改进的高温机械性能（~2.2 MPa 强度和~220% @80 °C 的断裂伸长率）和良好的阻尼性能（棕褐色δ = 0.42)。此外，通过调整化学交联的数量，可以达到平衡的再加工性和弹性恢复。因此，我们的工作可以为高性能热塑性聚烯烃弹性体的结构设计和相关弹性机制提供指导。