Thermoset networks are chemically cross-linked materials that exhibit high heat resistance and mechanical strength; however, the permanently cross-linked system makes end-of-life degradation difficult. Thermosets that are inherently degradable and made from renewably derived starting materials are an underexplored area in sustainable polymer chemistry. Here, we report the synthesis of novel sugar- and terpene-based monomers as the enes in thiol–ene network formation. The resulting networks showed varied mechanical properties depending on the thiol used during cross-linking, ranging from strain-at-breaks of 12 to 200%. Networks with carveol or an isosorbide-based thiol incorporated showed plastic deformation under tensile stress testing, while geraniol-containing networks demonstrated linear stress–strain behavior. The storage modulus at the rubbery plateau was highly dependent on the thiol cross-linker, showing an order of magnitude difference between commercial PETMP, DTT, and synthesized Iso2MC. Thermal degradation temperatures were low for the networks, primarily below 200 °C, and the T_g values ranged from −17 to 31 °C. Networks were rapidly degraded under basic conditions, showing complete degradation after 2 days for nearly all synthesized thermosets. This library demonstrates the range of thermal and mechanical properties that can be targeted using monomers from sugars and terpenes and expands the field of renewably derived and degradable thermoset network materials.

中文翻译：

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来自异山梨醇和萜烯的生物基硫醇-烯网络热固性材料


热固性网络是化学交联材料，具有高耐热性和机械强度；然而，永久交联系统使得报废降解变得困难。本质上可降解且由可再生衍生原材料制成的热固性材料是可持续聚合物化学中尚未开发的领域。在这里，我们报告了新型糖基和萜烯基单体的合成，作为硫醇-烯网络形成中的烯。所得网络表现出不同的机械性能，具体取决于交联过程中使用的硫醇，断裂应变范围为 12% 至 200%。含有香芹醇或基于异山梨醇的硫醇的网络在拉伸应力测试下表现出塑性变形，而含有香叶醇的网络表现出线性应力-应变行为。橡胶平台的储能模量高度依赖于硫醇交联剂，显示出商业 PETMP、DTT 和合成 Iso2MC 之间存在数量级差异。网络的热降解温度较低，主要低于 200 °C，T _g 值范围为 -17 至 31 °C。网络在基本条件下迅速降解，几乎所有合成热固性材料在 2 天后完全降解。该库展示了可以使用糖和萜烯单体实现的热和机械性能范围，并扩展了可再生衍生和可降解热固性网络材料的领域。