聚苯乙烯催化加氢制备高性能聚环己烷乙烯催化剂多级结构尺度调控制备及构效关系

Polystyrene (PS) is one of the most widely used general-purposed plastics in the market, which has excellent transparency. However, PS has poor impact resistance and low heat, ozone, and UV-light stabilities. By saturating aromatic rings hung on the chains, PS can be produced to polycyclohexylethylene (PCHE) with greatly improved integrated performance, whose thermal water resistance even surpasses PC. Therefore, PCHE is a prospective high-performance polymer material for optical signal storage medium, high-precision instruments, electronic apparatus, railway vehicle, and spacecraft. .To match the characteristics of PS hydrogenation system with high viscosity and large molecular size, we will design and evaluate a novel structured catalyst - Pd supported on the composite of CNF/CNT and ceramic foams (Pd/CNF@MCF, Pd/CNT@MCF). The physical and chemical properties of the multi-scale structured catalysts will be adjusted, including the ceramic struts, foam window, MCF surface, active metals (M=Fe, Co, Ni) for CNF/CNT growth, CNF/CNT layer, and nano Pd particles. The effect of catalyst properties on the adsorption-desorption behavior of PS, PCHE, H2, and solvent will be further investigated. By consolidating the catalytic performances and catalyst properties, the structure-activity relationship would be conducted. This project would provide good theoretical foundations for the industrial utilization of PS hydrogenation.

聚苯乙烯(PS)是五大通用树脂之一,高透明,但性脆,不耐热、紫外和臭氧。PS催化加氢得到聚环己烷乙烯(PCHE),综合性能大大提高,可与聚碳酸酯(PC)媲美,抗热水性能超过PC,是一种高性能新型工程塑料,可应用于光电信号存储、精密光学仪器、电子电气、高速铁路、城市地铁、航空航天等领域。针对PS分子线团尺度大、溶液黏度高对催化剂结构的特殊要求,提出制备块状泡沫陶瓷为载体、生长CNF/CNT、再负载Pd的多级结构尺度的新型催化剂(Pd/CNF@MCF、Pd/CNT@MCF),用于PS催化加氢。研究催化剂的多级结构尺度(骨架、泡孔、孔壁、CNF/CNT生长的纳米金属催化剂、CNF/CNT、纳米Pd)、物化性质的调控制备,研究多级结构尺度与PS、PCHE、H2和溶剂的竞争吸附行为的关系,研究多级结构尺度催化剂的PS加氢活性,建立构效关系,得到规律性认识,为PS催化加氢高性能化提供理论指导。

聚苯乙烯（PS）加氢改性可制备得到高性能高附加值新型聚合物材料聚环己基乙烯（PCHE）。PS加氢体系具有高分子线团尺寸大、溶液黏度高的特性，催化加氢过程中的分子尺度效应和溶液粘滞效应严重阻碍了PS加氢反应中的质量传递过程。将传统粉末状催化剂用于PS加氢中，出现加氢活性低和催化剂后续分离过程繁杂等关键问题。为弱化分子尺度效应与粘滞效应，本项目从整体式催化剂结构的理性设计与可规模化制备出发，开展相应的实验研究与机理研究，以商业量产泡沫陶瓷与泡沫金属为基底，设计制备基于碳纳米管外开放型整体式催化剂，实现活性组分在碳纳米管表面的高度分散且稳定锚定，并最大限度地降低由分子尺寸效应和溶液粘滞效应导致的传质受限，显著提升催化剂催化PS加氢活性，同时也解决了催化剂与产物分离困难的工程问题，为PS加氢工业化提供机理性认识基与可行性。另外，项目系统研究了整体式催化剂制备条件、微观结构与催化PS加氢反应活性之间的构效关系与机理，并采用吸附实验结合分子模拟的方法，从聚合物分子与CNTs相互作用的角度，解释催化剂高活性的机理。基于整体式催化剂的研究基础，本项目将碳纳米管基整体式催化剂的应用进一步拓宽至丁腈橡胶（NBR）选择性加氢制备氢化丁腈橡胶（HNBR）和强放热丙烯环氧化制备环氧丙烷等扩散控制诸多体系中，展现出极大的工业应用前景。