Recently, a simple strategy was developed for preparing interconnected interpenetrating polymer networks (IPNs) based on butyl rubber (IIR) and poly(n-octadecyl acrylate) (PC18A). Solvent-free UV polymerization of n-octadecyl acrylate (C18A) monomer in the melt of IIR at ambient temperature resulted in IPNs with self-healing and shape-memory functions. Here, we demonstrate that the use of IIR grafted with acrylic acid, methacrylic acid, and 10-undecenoic acid instead of unmodified IIR provides a significant improvement in the mechanical properties of IPNs. Differential scanning calorimetry, small-angle x-ray scattering, and wide-angle x-ray scattering analysis reveal side-by-side packing of C18 side chains of PC18A to form lamellar crystals with a melting temperature T_m between 46 and 52 °C. Transmission electron microscopy analysis indicates the existence of quasispherical nanoparticles composed of crystalline domains, which are dispersed in a continuous interpenetrating rubber-PC18A matrix. This microstructure provides them a complete self-recovery behavior induced by heating and an efficient shape-memory function. IPNs exhibit around tenfold higher chemical cross-link density as compared to those prepared from the native IIR, reflecting the effect of pendant vinyl groups on the extent of covalent interconnections between the IIR and PC18A components. The type of the grafted monomers significantly affects the mechanical performance of IPNs, which can be explained with the individual contributions of chemical and physical cross-links to the total cross-link density. The amount of the grafted rubbers in IPN could be further increased up to 80 wt. % by the incorporation of toluene into the reaction system, resulting in IPNs with a wide range of tunable thermal and mechanical properties.

中文翻译：

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丁基橡胶作为宏观交联剂制备形状记忆和自愈聚合物

最近，开发了一种简单的策略来制备基于丁基橡胶（IIR）和聚（丙烯酸正十八烷基酯）（PC18A）的互连互穿聚合物网络（IPN）。丙烯酸正十八烷基酯 (C18A) 单体在环境温度下的 IIR 熔体中的无溶剂紫外聚合产生了具有自愈和形状记忆功能的 IPN。在这里，我们证明使用丙烯酸、甲基丙烯酸和 10-十一碳烯酸接枝的 IIR 代替未改性的 IIR 可以显着改善 IPN 的机械性能。差示扫描量热法、小角 X 射线散射和广角 X 射线散射分析揭示了 PC18A 的 C18 侧链并排堆积形成具有熔化温度T的层状晶体_米在 46 和 52 °C 之间。透射电子显微镜分析表明存在由结晶域组成的准球形纳米粒子，它们分散在连续互穿的橡胶-PC18A 基质中。这种微结构为它们提供了由加热引起的完全自我恢复行为和有效的形状记忆功能。与由天然 IIR 制备的相比，IPN 的化学交联密度高出约 10 倍，这反映了乙烯基侧基对 IIR 和 PC18A 组件之间共价互连程度的影响。接枝单体的类型显着影响 IPN 的机械性能，这可以用化学和物理交联对总交联密度的单独贡献来解释。IPN 中接枝橡胶的量可进一步增加到 80 wt. % 通过将甲苯掺入反应系统中，产生具有广泛可调热和机械性能的 IPN。