Photo-alignment Property of Azobenzene-containing Polyimide Films Swollen by Alkyl-amine

Photo-alignment efficiency of polyimide containing azobenzene in the backbone structure (Azo-PI) is significantly enhanced by exposing the precursor (polyamic acid: Azo-PAA) film to alkyl-amine vapor prior to photo-alignment. In this study, we have investigated the relationships between the alkyl-amine vapor treatment time, the swelling ratio of Azo-PAA films, and the photo-induced in-plane anisotropy. We found that: the Azo-PAA film swells on exposure to alkyl-amine vapor, and the swelling finally saturates; and the photo-induced in-plane anisotropy is correlated very closely with the swelling ratio. In addition, we pointed out the importance of the process order of alkyl-amine vapor treatment and photo-alignment.     

Fabrication of flame-retardant and smoke-suppressant isocyanate-based polyimide foam modified by silica aerogel thermal insulation and flame protection layers

Because of containing urea groups, flame resistance and smoke releasing behaviors of isocyanate-based polyimide foam (IBPIF) produced using free foaming technology require further improvement. In this work, silica aerogel layers were incorporated into cells of IBPIF through an in situ growth process of silica sol (SS). Compared with silica aerogel particles directly mixed into the foaming slurry, the silica aerogel layers that firmly attached to the pores and surfaces of cells not only provided exceptional thermal insulation and flame protection, but also kept original cellular structure. With increase in ratio of SS mass to IBPIF volume, silica aerogel incorporation dosage was gradually increased. Accompanied by flame resistance was obviously improved and smoke releasing behavior was effectively suppressed. Those were indicated by the improved limiting oxygen index (LOI), decreased heat release rate (HRR), peak of HRR, and specific optical density of smoke (Ds) in trials with pilot flames. Compared with pure IBPIF, when the ratio reached to 5/15 g/cm³, it resulted in LOI increasing from 22.0% to 33.0%, peak of HRR, total smoke production (TSP), and maximum value of Ds decreasing from 174 to 72 kW/m², 1.11 to 0.37 m²/m², 45.90 to 17.45, respectively.     

Preparation of polyimide/BaTiO3‐nanocrystal hybrid thin films and their dielectric property

High dielectric constant is highly desirable in capacitors and memory devices. In this work, oleic acid (OA)‐capped BaTiO₃ nanocrystals were synthesized by a two‐phase approach. Polyimide (PI)/BaTiO₃‐nanocrystal composite thin films with high dielectric constant have been successfully fabricated. The morphologies and dielectric properties of the hybrid films were exploited. The results showed that BaTiO₃ nanocrystals can be uniformly dispersed in the PI thin films owing to the surface modification of OA‐capped BaTiO₃ nanocrystals. It was found that the dielectric constant of composite film varies with the volume fraction of BaTiO₃ nanocrystals and sintering temperatures and reaches a maximum value of 44.1, which is around 13 times higher than that of pristine PI thin film (3.2). These results demonstrated that PI/BaTiO₃‐nanocrystal composite films have considerable application potential in microelectronic fields.     

一种新型偶氮染料在扭曲向列相液晶显示取向中的应用

研究了一种新型偶氮材料sy03在光控取向中的应用。将sy03加入聚酰亚胺SE-3310(Nissan)与N,N-二甲基甲酰胺(DMF)的混合溶液中作为90°扭曲向列相液晶显示(Twisted nematic liquid crystal display,TN-LCD)的光取向材料,测量由它作为取向膜的扭曲向列型盒的电光特性与仅用SE-3310取向的扭曲向列型盒电光特性比较,发现sy03偶氮的加入使得扭曲向列型盒的响应时间短到98 ms、阈值电压也降低到1.7 V左右。而且随曝光时间的增加,响应时间和衬比度都有所提高,电光响应曲线也更为陡峭。加热到150℃后,其电光特性并没有明显变化,证明了它良好的热稳定性。最后通过测量偏振紫外吸收光谱,分析得出液晶分子易取向方向与激发光源偏振方向垂直。     

聚酰亚胺LB膜研究进展

阐述近年来聚酰亚胺ＬＢ膜研究的发展概况，包括聚酰亚胺ＬＢ膜的制备方法、结构、性能及应用。     

银菊珍珠胶囊中稀土元素的电感耦合等离子体质谱分析

建立了一种电感耦合等离子体质谱法测定银菊珍珠胶囊中稀土元素的方法。利用该方法分析了国家一级灌木枝叶标准物质（GBW 07603）和国际柑橘叶标准物质（NIST1572）中的稀土元素,结果与标准值一致。该方法已被用于分析银菊珍珠肢囊样品中的稀土元素。     

Synthesis and characterization of thermally crosslinked polyimide with second-order nonlinear optical chromophore

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含磷聚酰亚胺纤维的制备及其力学与阻燃性能

采用廉价的三苯基氧膦和混酸合成了一种含磷二胺单体,二（3-氨基苯基）苯基膦氧(DAPPO)。在4,4′-二胺基二苯醚（ODA）、3,3′,4,4′-联苯四酸二酐（BPDA）和均苯四酸二酐（PMDA）聚合体系中引入该单体,制备含磷聚酰亚胺纤维。热失重分析（TGA）结果表明,聚酰亚胺纤维的热稳定性随含磷量的增加而明显提高。当n（DAPPO）：n（ODA）为7：93时,纤维的极限氧指数达到了43,说明纤维的阻燃性能显著提高。     

短侧链可溶性聚酰亚胺的制备和表征

利用3种廉价易得的含短侧链(甲基或乙基)芳香族二胺单体分别与3,3′,4,4′-二苯甲醚四酸二酐(ODPA)进行溶液缩聚反应制备了聚酰胺酸,再在三乙胺催化、乙酸酐脱水作用下进行化学亚胺化反应,成功制备出聚酰亚胺(PI)。通过红外光谱(FT-IR)证明PI已经完全亚胺化。溶解性实验表明这3种PI具有优异的溶解性能,如:在极性非质子溶剂1-甲基-2-吡咯烷酮(NMP)、N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAc)、二甲基亚砜(DMSO)乃至低沸点溶剂氯仿和四氢呋喃(THF)中都可以溶解。采用DSC、TG、频谱分析仪、交流耐压试验装置、电阻测量仪、万能电子拉力机等多种手段对PI薄膜进行了性能测试。结果表明这3种PI保持了优良的热性能、电性能、力学性能等。     

胶束增强型聚电解质微胶囊的制备

采用杂化碳酸钙微球作为模板, 利用LbL技术, 选择聚苯乙烯磺酸钠(PSS), 烯丙基胺的盐酸盐(PAH)和二烯丙基二甲基胺盐酸盐(PADA)聚电解质, 分别组装了PAH/PSS(弱/强)聚电解质胶囊和PADA/PSS(强/强)聚电解质微胶囊. 除去模板后得到了球形良好、分散均匀的聚电解质微胶囊. 研究结果表明, 利用杂化碳酸钙微球作为聚电解质微胶囊的模板, 得到的微胶囊的囊壁厚而致密, 同时, 由于组装采用的聚电解质的种类不同, 囊壁的微观形貌有较大差异.