Copolymerization of a Bisphenol a Derivative and Elemental Sulfur by the RASP Process
Copolymerization of a Bisphenol a Derivative and Elemental Sulfur by the RASP Process
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DOI：
10.3390/suschem1020013
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发表时间：
2020-09
影响因子：
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通讯作者：
Timmy Thiounn;Moira K. Lauer;M. S. Karunarathna;Andrew G. Tennyson;Rhett C. Smith
中科院分区：
文献类型：
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作者：
Timmy Thiounn;Moira K. Lauer;M. S. Karunarathna;Andrew G. Tennyson;Rhett C. Smith
化石燃料精炼每年产生超过7000万吨的过量硫，目前没有实际用途。最近，已经描述了将废硫转化为可回收和可生物降解的聚合物的方法。以双酚A（BPA）衍生物2，2 ′，5，5 ′-四溴双酚A（Br 4 BPA）为单体，通过RASP（自由基诱导卤代芳烃-硫聚合）与单质硫进行共聚反应。所得共聚物BASx（x =单体进料中硫的重量%，筛选值为80、85、90和95）通过热重分析、差示扫描量热法和动态力学分析表征。早期反应产物和解聚产物的分析支持提出的S-羧基键形成和区域化学，而BASx的分馏揭示了3-6的硫等级。在单体进料中具有较少有机交联剂（5或10重量%）的共聚物是热塑性的，而当使用15或20重量%的有机交联剂时实现热固性。可热加工样品的弯曲强度（对于BAS 95和BAS 90分别> 3.4MPa和>4.7）与常见建筑材料如波特兰水泥的弯曲强度（3.7MPa）相比相当高。此外，共聚物BAS 90被证明对氧化有机酸的降解具有相当的抗性，在0.5 M H2SO 4中浸泡24 h后保持其完全的弯曲强度。BAS 90也可以在许多循环中重熔和重铸成形状，而不会损失任何机械强度。本研究的单体比例对小分子芳基卤化物的RASP制备的材料的性能的影响证实，具有不同的物理和机械性能的高度交联的材料可以通过该协议访问。这项工作也是从塑料降解中回收BPA和从化石燃料精炼中回收硫的重要一步。
Fossil fuel refining produces over 70 Mt of excess sulfur annually from for which there is currently no practical use. Recently, methods to convert waste sulfur to recyclable and biodegradable polymers have been delineated. In this report, a commercial bisphenol A (BPA) derivative, 2,2′,5,5′-tetrabromo(bisphenol A) (Br4BPA), is explored as a potential organic monomer for copolymerization with elemental sulfur by RASP (radical-induced aryl halide-sulfur polymerization). Resultant copolymers, BASx (x = wt% sulfur in the monomer feed, screened for values of 80, 85, 90, and 95) were characterized by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. Analysis of early stage reaction products and depolymerization products support proposed S–Caryl bond formation and regiochemistry, while fractionation of BASx reveals a sulfur rank of 3–6. Copolymers having less organic cross-linker (5 or 10 wt%) in the monomer feed were thermoplastics, whereas thermosets were accomplished when 15 or 20 wt% of organic cross-linker was used. The flexural strengths of the thermally processable samples (>3.4 MPa and >4.7 for BAS95 and BAS90, respectively) were quite high compared to those of familiar building materials such as portland cement (3.7 MPa). Furthermore, copolymer BAS90 proved quite resistant to degradation by oxidizing organic acid, maintaining its full flexural strength after soaking in 0.5 M H2SO4 for 24 h. BAS90 could also be remelted and recast into shapes over many cycles without any loss of mechanical strength. This study on the effect of monomer ratio on properties of materials prepared by RASP of small molecular aryl halides confirms that highly cross-linked materials with varying physical and mechanical properties can be accessed by this protocol. This work is also an important step towards potentially upcycling BPA from plastic degradation and sulfur from fossil fuel refining.