We report here the synthesis of a novel substituted polyvalerolactone from the renewable monomer, 4-carbomethoxyvalerolactone (CMVL, two steps from malic acid). The polymerization proceeds to high equilibrium monomer conversion to give the semicrystalline carbomethoxylated polyester with low dispersity. The material displays a glass transition temperature of −18 °C and two melting temperatures at 68 and 86 °C. This polymer can be chemically recycled by either of two independent pathways. The first (red) cleanly returns CMVL by a backbiting depolymerization from the hydroxy terminus; the second (blue) uses a base to cleave the polyester in a retro-oxa-Michael fashion. This affords a methacrylate-like monomer that we have polymerized radically to a new polymethacrylate analogue. This is a rare example of a polymer that has been shown to have two independent chemical recycling pathways leading to two different classes of monomers.

中文翻译：

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来自苹果酸的甲氧基化聚戊内酯：合成和发散化学回收

我们在此报告了从可再生单体 4-甲氧基戊内酯（CMVL，苹果酸两步法）合成一种新型取代聚戊内酯。聚合进行到高平衡单体转化率，得到具有低分散性的半结晶甲氧基化聚酯。该材料的玻璃化转变温度为 -18 °C，两个熔化温度分别为 68 和 86 °C。这种聚合物可以通过两种独立途径中的任何一种进行化学回收。第一个（红色）干净地返回CMVL通过从羟基末端的不利解聚；第二个（蓝色）使用碱基以复古-oxa-Michael 方式切割聚酯。这提供了一种类似甲基丙烯酸酯的单体，我们已经将其自由基聚合成一种新的聚甲基丙烯酸酯类似物。这是一种罕见的聚合物示例，它已被证明具有两条独立的化学循环途径，导致两种不同类型的单体。