Microstructure evolution and enhanced permeation of SiC membranes derived from allylhydridopolycarbosilane
Microstructure evolution and enhanced permeation of SiC membranes derived from allylhydridopolycarbosilane
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DOI：
10.1016/j.memsci.2020.118392
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发表时间：
2020-10
影响因子：
9.5
通讯作者：
Qing Wang;Makoto Yokoji;Hiroki Nagasawa;Liang Yu;M. Kanezashi;T. Tsuru
中科院分区：
文献类型：
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作者：
Qing Wang;Makoto Yokoji;Hiroki Nagasawa;Liang Yu;M. Kanezashi;T. Tsuru
采用DLS、TG、FTIR、XRD和EDS等手段系统研究了烯丙基聚碳硅烷（AHPCS）的物化性能的演变过程。通过将AHPCS溶胶涂覆到多孔基底上，然后在300-800 °C下热解来制备AHPCS衍生的膜。通过热固化的预交联显著增加了AHPCS在甲苯溶液中的溶胶尺寸，这有效地减少了对基底的渗透，增强了气体渗透。此外，AHPCS衍生膜的孔结构可以通过热解温度精确地定制，并且结果表明，膜的结构可以大致分为三种类型之一：致密聚合物结构、松散过渡结构和致密陶瓷结构（这里，术语“致密/较致密”是指小/较小的孔结构，而“松散”是指大孔结构）。在300-800 °C下在N2气流下制备的AHPCS衍生膜在200 ° C下显示出（0.2-5）× 10− 6 mol/（m2 s Pa）的上级的H2渗透性和12-56的良好H2/N2选择性。在700 °C下制备的陶瓷SiC膜在200 °C下显示出（2-4）× 10− 6 mol（m2 s Pa）− 1的有吸引力的H2渗透率，H2/N2选择性为16-22，H2/SF6选择性高于10，000，N2/SF6选择性高于800。此外，陶瓷SiC膜的结构是高度稳定的，具有良好的抗氧化性在500 °C下在空气中。在300-800 °C下制备的AHPCS膜具有不同的孔结构，这些孔结构表现出高水平的质量和多种渗透性能，这可以在广泛的应用范围内为膜材料提供许多选择。
The evolution of the physicochemical properties of allylhydridopolycarbosilane (AHPCS) was systematically investigated via DLS, TG, FTIR, XRD, and EDS. AHPCS-derived membranes were prepared by coating AHPCS sols onto porous substrates, which was then followed by pyrolysis at 300–800 °C. The pre-crosslinking by thermal curing significantly increased the colloidal sol size of AHPCS in toluene solutions, which effectively reduced penetration into substrates and enhanced the gas permeation. Furthermore, the pore structure of AHPCS-derived membranes could be precisely tailored by the pyrolysis temperatures, and the results indicated that the structure of membranes could be roughly classified into one of three types: a dense polymer structure, a loose transitional structure, and a denser ceramic structure (here, the term ‘dense/denser’ refers to the small/smaller pore structure, while the ‘loose’ refers to the large pore structure). AHPCS-derived membranes prepared at 300–800 °C under a N2flow displayed superior H2permeance of (0.2–5) × 10−6mol/(m2s Pa) at 200 °C with good H2/N2selectivity of 12–56. Ceramic SiC membranes prepared at 700 °C showed an attractive H2permeance of (2–4) × 10−6mol (m2s Pa)−1at 200 °C with H2/N2selectivity of 16–22, H2/SF6selectivity higher than 10,000, and N2/SF6selectivity higher than 800. Moreover, the structure of the ceramic SiC membranes was highly stable with good oxidation resistance at 500 °C under air. AHPCS membranes prepared at 300–800 °C had different pore structures that exhibited a high level of quality and a variety of permeation properties that could provide many options for membrane materials over a wide range of applications.