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首页> 外文学位 >Physical and gas permeation properties of a series of novel hybrid inorganic-organic composites based on a synthesized fluorinated polyimide.
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Physical and gas permeation properties of a series of novel hybrid inorganic-organic composites based on a synthesized fluorinated polyimide.

机译：基于合成的氟化聚酰亚胺的一系列新型杂化无机-有机复合材料的物理和气体渗透性能。

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A series of hybrid inorganic-organic composites were fabricated from a functionalized fluorinated polyimide and tetraethoxysilane (TEOS), tetramethoxysilane, methyltrimethoxysilane (MTMOS), and phenyltrimethoxy-silane (PTMOS) employing the sol-gel process. Polyimides were synthesized from 4,4'-hexafluoroisopropylidene dianiline (6FpDA) and 4,4'-hexafluoroisopropyl-idenediphthalic anhydride (6FDA) utilizing a solution imidization technique. The hybrid materials were synthesized by in-situ sol-gel processing of the aforementioned alkoxides and a fully imidized polyimide that was functionalized with 3-aminopropyltriethoxysilane. The gas permeability, diffusivity, and selectivity were evaluated for He, O2, N2, CH4, and CO2, while the physical properties of these hybrid materials were evaluated using several analytical techniques. The results from this study revealed that gas transport and physical properties were dependent on the type of alkoxide employed in the hybrid inorganic-organic material. Gas permeability was observed to increase with increasing gas penetrant size for MTMOS and PTMOS based hybrids, while TEOS based hybrids decreased gas permeability at all compositions. In general, MTMOS based hybrid materials had the largest increases in permeability, which was attributed to an increase in free volume. The TEOS based hybrid materials had the largest decreases in permeability, while PTMOS based hybrid materials had performance in between these alkoxides. Decreased permeability for the TEOS based hybrids was attributed to the formation of lower permeable material at a particle interface and coupled with increasing tortuosity. Results of PALS studies suggested that there was an increase in free volume and pore size for MTMOS based hybrids, while both TEOS and PTMOS based hybrids had decreases in both average pore size and free volume. The temperature dependence of permeation, diffusivity, and sorption were evaluated from 35°C to 125°C. These results suggested that there was a decrease in solubility for all hybrids employed in this study. Furthermore, increases in permeability for the MTMOS based hybrids were created by increased penetrant diffusion. Physical property studies revealed that the type of inorganic material incorporated into the hybrid influences the degree of swelling, bulk density, Tg, and thermal stability. Hybrid materials were also created employing 3,5-diaminobenzoic acid (DABA) in the synthesis of modified 6FDA-6FpDA polyimides in order to evaluate how improvements in inorganic and polymer compatibility influenced the gas transport properties. From this separate study, it was found that increases in both permeability and selectivity were possible. The mechanism attributed to this simultaneous increase in permeability and selectivity was the formation of a more permeable and selective interphase at the interface of an inorganic particle and the polymer matrix. In addition to these studies, 6FDA-6FpDA polyimide molecular weights were changed from 19.3K Mn to 35.3K M n to probe its role on gas transport and physical properties. These studies revealed that permeability, diffusivity, and solubility increased with increasing molecular weight, while density decreased with increasing molecular weight. These results suggest that there is an increase in free volume with increasing 6FDA-6FpDA polyimide molecular weight.
机译：通过功能化的氟化聚酰亚胺和四乙氧基硅烷（TEOS），四甲氧基硅烷，甲基三甲氧基硅烷（MTMOS）和苯基三甲氧基硅烷（PTMOS）采用溶胶-凝胶法制备了一系列杂化的无机-有机复合材料。利用溶液酰亚胺化技术，由4,4'-六氟异亚丙基二苯胺（6FpDA）和4,4'-六氟异丙基-亚二苯二酸酐（6FDA）合成聚酰亚胺。杂化材料是通过原位溶胶-凝胶处理上述醇盐和被3-氨基丙基三乙氧基硅烷官能化的完全酰亚胺化的聚酰亚胺合成的。评估了He，O2，N2，CH4和CO2的气体渗透性，扩散性和选择性，同时使用多种分析技术评估了这些杂化材料的物理性质。这项研究的结果表明，气体传输和物理性质取决于杂化无机有机材料中所用的醇盐类型。对于基于MTMOS和PTMOS的混合气体，观察到气体渗透率随气体渗透剂尺寸的增加而增加，而基于TEOS的混合气体在所有成分下均降低了气体渗透率。通常，基于MTMOS的混合材料的磁导率增加最大，这归因于自由体积的增加。基于TEOS的杂化材料的磁导率降低最大，而基于PTMOS的杂化材料的性能介于这些醇盐之间。基于TEOS的杂化材料的渗透性降低归因于在颗粒界面处形成了较低渗透性的材料，并伴随着曲折度的增加。 PALS研究的结果表明，基于MTMOS的杂化物的自由体积和孔径都有所增加，而基于TEOS和PTMOS的杂化物的平均孔径和自由体积均有所减少。在35°C至125°C范围内评估了渗透率，扩散率和吸附的温度依赖性。这些结果表明该研究中使用的所有杂种的溶解度均降低。此外，通过增加渗透剂扩散，使基于MTMOS的混合材料的磁导率增加。物理性能研究表明，掺入杂化物中的无机材料的类型会影响溶胀程度，堆积密度，Tg和热稳定性。为了评估无机和聚合物相容性的改善如何影响气体传输性能，还使用3,5-二氨基苯甲酸（DABA）合成了改性的6FDA-6FpDA聚酰亚胺，从而形成了杂化材料。从这项单独的研究中，发现增加渗透率和选择性都是可能的。渗透率和选择性同时增加的机理是在无机颗粒和聚合物基质的界面上形成了更具渗透性和选择性的中间相。除了这些研究之外，还将6FDA-6FpDA聚酰亚胺的分子量从19.3K Mn更改为35.3K M n，以探究其对气体传输和物理性质的作用。这些研究表明，渗透性，扩散性和溶解度随分子量的增加而增加，而密度随分子量的增加而降低。这些结果表明，自由体积随6FDA-6FpDA聚酰亚胺分子量的增加而增加。

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