Effect of thermal treatment on the structure and gas transport properties of a triptycene-based polybenzoxazole exhibiting configurational free volume
Effect of thermal treatment on the structure and gas transport properties of a triptycene-based polybenzoxazole exhibiting configurational free volume
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热处理对具有构型自由体积的三蝶烯基聚苯并恶唑的结构和气体传输性能的影响
DOI：
10.1016/j.memsci.2019.117759
复制
发表时间：
2020
影响因子：
9.5
通讯作者：
Galizia, M.
中科院分区：
文献类型：
--
作者：
Crist, R.D;Huang, Z;Guo, R;Galizia, M.
从实验和理论上研究了220° C热处理10天对三蝶烯基聚苯并恶唑（TPBO）结构和输运性质的影响。TPBO中的气体和水蒸气吸附几乎不受热处理的影响，而扩散和渗透系数仅降低20%。值得注意的是，CO2/CH 4选择性表现出可忽略不计的变化。荧光光谱，WAXD和FTIR分析表明，与典型的玻璃态聚合物的行为形成鲜明对比，TPBO不经历加速的物理老化，并排除在热处理后形成的分子间电荷转移复合物。根据这一物理图像，在朗缪尔模式下吸附的渗透剂分子的扩散系数，DH，处理后不改变。小分子扩散率和渗透率下降是由聚合物链流动性的降低引起的，这使得更难以打开间隙以允许渗透剂扩散跳跃。根据该图，亨利模式扩散系数D D在热处理时显著降低。TPBO相对于其他高Tg玻璃态聚合物表现出的更高的稳定性归因于构型自由体积的存在，这与非平衡瞬态构象无关，但与分子构型有关，因此，在长期暴露于高温下时不会放松。
The effect of thermal treatment at 220° C for 10 days on the structure and transport properties of a triptycene-based polybenzoxazole (TPBO) was investigated experimentally and theoretically. Gas and water vapor sorption in TPBO is virtually unaffected by thermal treatment, while diffusion and permeability coefficients decrease by just 20%. Remarkably, the CO 2/CH 4 selectivity exhibit a negligible change. Fluorescence spectroscopy, WAXD and FTIR analysis indicate that, in sharp contrast with typical behavior of glassy polymers, TPBO does not experience accelerated physical aging, and rule out formation of intermolecular charge transfer complexes upon thermal treatment. According with this physical picture, the diffusion coefficient of penetrant molecules sorbed in the Langmuir's mode, D H, does not change after treatment. Small molecule diffusivity and permeability decline is caused by a decrease in polymer chain mobility, which makes more difficult opening gaps to allow penetrant diffusion jumps. According to this picture, the Henry's mode diffusion coefficient, D D, substantially decreases upon thermal treatment. The higher stability exhibited by TPBO relative to other high T g glassy polymers is ascribed to the presence of configurational free volume, which is not related to the non-equilibrium transient conformation, but to the molecular configuration and, as such, it is not relaxed upon protracted exposure to high temperatures.
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影响因子：
4.6
作者：
Bernardo, P.;Bazzarelli, F.;Jansen, J. C.
通讯作者：
Jansen, J. C.
影响因子：
9.5
作者：
Li, P.;Chung, T. S.;Paul, D. R.
通讯作者：
Paul, D. R.
估计参数曲线拟合中的误差限度
影响因子：
7.4
作者：
M. Caceci
通讯作者：
M. Caceci
影响因子：
9.5
作者：
R. R. Tiwari-R.;Jianyong Jin;B. Freeman;D. R. Paul
通讯作者：
R. R. Tiwari-R.;Jianyong Jin;B. Freeman;D. R. Paul
气体吸附
DOI：
--
发表时间：
2020
期刊：
Definitions
影响因子：
--
作者：
S. Rigby
通讯作者：
S. Rigby