聚酰亚胺泡沫塑料制备与性能研究

采用一步缩聚法制备了聚酰亚胺(PI)泡沫塑料,并对其结构和性能进行了表征。经红外光谱测定,在1778、1720cm-1和1375cm-1处观察到PI特征峰。实验结果表明,所得PI泡沫塑料孔径均匀,平均密度小于0.30g/cm3,极限氧指数为38%,平均吸声系数为0.42,玻璃化转变温度为262.4℃,起始分解温度为549.7℃。     

聚酰亚胺泡沫塑料开发研究概述

介绍了聚酰亚胺泡沫塑料的6种合成方法和制备工艺中所应注意的几个方面(发泡方法、泡孔大小和形状控制等)。并综述了聚酰亚胺泡沫塑料的高低温性、高抗拉强度、高弹性模量、耐辐射性、高介电性能等优异的性能及其在透波材料、阻尼材料、耐高温材料、低放气材料、低温材料、复合材料、介电材料等方面的应用。聚酰亚胺泡沫塑料的发展还应有更广阔的空间。     

粉末法制备聚酰亚胺泡沫塑料

以芳香二酐和二胺为单体,甲醇/四氢呋喃为溶剂,通过酯化法合成聚酯铵盐前驱体粉末、粉末法制备泡孔均匀的聚酰亚胺泡沫塑料.采用扫描电子显微镜照片、傅里叶变换红外光谱和热重分析表征泡沫材料结构及耐热性能,研究了初始加热温度、粉末粒径对泡沫密度的影响.结果表明:初始加热温度越高,泡沫密度越小.粉末粒径对泡沫密度影响较小.     

聚酰胺酸合成工艺与聚酰亚胺膜制备及表征

聚酰亚胺是一类新型高性能的聚合物材料,是由聚酰胺酸脱水环化而成,因此高分子量的聚酰胺酸是获得高性能PI的前提。探讨了聚酰胺酸合成过程中的影响因素,得出了合成高分子量的聚酰胺酸的最佳工艺条件为:均苯四羧酸二酐与4,4' 二氨基二苯醚摩尔比为1.015～1.020∶1,反应温度20℃,反应时间为3h,聚酰胺酸在N 甲基 2 吡咯烷酮中的特性粘度为0.62dL/g左右。采用热转化法将聚酰胺酸脱水环化制备成均苯型聚酰亚胺膜,通过差示扫描量热法、红外光谱等进行了表征,其玻璃化转变温度为365～385℃,拉伸强度达192.4MPa,表明得到的聚酰亚胺膜具有优良的机械性能。     

聚酰亚胺泡沫塑料的合成路线及制备工艺

在对聚酰亚胺泡沫进行分析发现,其种类相对比较复杂,其密度不仅可以自行调整,而且具有较强的绝缘性,尤其表现为耐高低温和耐辐射,低发烟以及难燃等性能,其中耐高低温可以达到-250~450℃,以上优势均是原有泡沫塑料无法替代的,因此聚酰亚胺泡沫塑料具有较为良好的应用前景。基于此文章对聚酰亚胺泡沫塑料的合成路线及制备工艺进行详细分析,意在不断挖掘其价值和功能,并将其广泛应用于航空航天以及国防等领域。     

酯化法合成聚酰亚胺泡沫塑料的研究

以3,3',4,4'-二苯酮四酸二酐、3,3',4,4'-二苯醚四酸二酐、4,4'一二胺基二苯甲烷、4,4'-二胺基二苯醚和4,4'-二胺基二苯砜为单体,甲醇和四氢呋喃混合溶剂,采用酯化法制备了5种聚酰亚胺(PI)泡沫塑料.红外光谱分析证实,由二酐的二酸二酯和二胺反应生成了聚酯铵盐前驱体(PEAS),且通过微波辐照发泡方法由PEAS粉末成功制得了PJ泡沫塑料.结果表明,5种PI泡沫塑料平均密度为11 kg/m<'3>,阻燃性能和耐高温性能优异,四元共聚型的P14和P15泡沫塑料压缩永久形变最小、耐高温性能最佳.     

三氟化硼的合成及工艺路线选择

论述了三氟化硼的多种合成方法,根据我国实际情况选择了4种工艺,既可用于实验室制备,也可用于工业化的生产。     

三氯乙酰氯合成的工艺路线

对三氯乙酰氯合成的各种工艺路线进行详细分析比较, 阐明了四氯乙烯液相催化氧化法是工业化制备三氯乙酰氯的最佳方法,并说明其工艺上特点。     

泡沫塑料的成型工艺（续一）

本文讲述了聚氯乙烯泡沫塑料进行了原料,配方及其制备工艺。     

Ignition and combustion of low‐density polyimide foam

The ignition, flaming and smoldering combustion of low‐density polyimide foam have been studied using a cone calorimeter. Low‐density polyimide foam exhibits a high ignition resistance. The minimum heat flux for the ignition of flaming combustion ranges from 48 to 54 kW/m². This minimum heat flux also indicates the heat flux for transition from smoldering to flaming combustion. The flaming combustion results show that the heat release rate of low‐density polyimide foam is very low even at a high incident heat flux of 75 kW/m². The smoldering combustion results show that the smoldering of low‐density polyimide foam becomes significant when the incident heat flux is greater than 30 kW/m². The smoldering combustion of low‐density polyimide foam cannot be self‐sustaining when the external heat source is removed. Copyright © 2003 John Wiley & Sons, Ltd.     

Preparation and characterization of electromagnetic interference shielding polyimide foam

This article focused on the preparation and characterization of ultralight and high‐temperature resistant polyimide foam (PIF) for electromagnetic interference shielding. PIF was first prepared based on a one‐pot process by the primary reactions of derivatives of pyromellitic dianhydride and polyaryl polymethylene isocyanate. Then, PIFs with silver (0) coating were then prepared by spraying silver (0) on the surfaces of PIF through physical spraying method. The surface density of silver coating was 0.18 kg/m², and the densities of silver‐coated PIFs were less than 23 kg/m³. The scanning electron microscopy coupled with an energy‐dispersive X‐ray spectrometer (EDX) measurement were carried out to investigate the morphological and chemical properties of uncoated and coated PIFs. For coated PIFs, the EDX spectrums indicated increasing higher silver proportions from interior to exterior surface, together with increasing higher carbon proportions from exterior surface to interior. Thermogravimetry/Fourier transform infrared instrument that combined thermogravimetric analysis with pyrolysis product analysis by Fourier transform infrared spectroscopy were applied to investigate the thermal stability and pyrolysis products of uncoated and coated PIFs. The results indicated that the thermal properties of silver‐coated PIFs were improved obviously with the 5% weight loss temperature higher than 400°C and the residual weight retentions at 800°C ～ 80%. In the frequency range 200–7000 MHz, the EMI shielding efficiency with one surface and two surfaces coated with silver were in the range of 36.4–60.7 dB and 61.6–95.6 dB, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

聚酰亚胺气凝胶制备、性能及应用进展

聚酰亚胺气凝胶具有高比表面积、低密度、低热导率等优点,但是存在易吸湿、收缩率大且在制备过程中大量使用有机溶剂以及使用价格昂贵的化学交联剂等问题。本文主要介绍了目前聚酰亚胺气凝胶的制备方法、性能及其应用,重点综述了二酐与二胺缩合反应法、异氰酸酯法、开环易位聚合法。简述了几种方法的制备原理,同时也总结了聚酰亚胺气凝胶在隔热、抗辐射、油水分离、过滤等领域应用的研究进展。最后,对聚酰亚胺气凝胶的制备方法及实际应用进行了总结与评价,提出在今后的研究工作中要以解决易吸湿、收缩率大、探索其他类型交联剂作为重点。并且,立足于目前聚酰亚胺气凝胶及其复合材料的发展趋势,对今后聚酰亚胺气凝胶新的存在形态、新的应用领域进行了展望。     

反应型磷氮阻燃剂/可膨胀石墨复配阻燃聚氨酯泡沫

将反应型阻燃剂六(4-磷酸二乙酯羟甲基苯氧基)环三磷腈(HPHPCP)和可膨胀石墨(EG)复配,制备了阻燃聚氨酯泡沫,详细研究了复配阻燃剂对聚氨酯泡沫的物理力学性能、热稳定性以及阻燃性能的影响。结果表明,阻燃聚氨酯泡沫的密度和热导率随着复配阻燃剂中EG含量的增加而升高;压缩强度随着EG含量的增加呈现先增加后降低的趋势。热失重表明复配阻燃剂大大提高了聚氨酯泡沫的热稳定性。聚氨酯泡沫的初始分解温度(T_10%)从212.9℃,分别提高到222.0、231.2和243.2℃;700℃残炭量从7.6%分别提高到26.3%、31.6%和37.9%。聚氨酯泡沫的阻燃性能随着复配阻燃剂中EG含量的增加而提高。阻燃聚氨酯泡沫的极限氧指数从19%提高到29%,均能通过UL-94水平燃烧HF-1等级和垂直燃烧V-0等级。     

三聚氰胺泡沫的制备及应用研究进展

介绍了三聚氰胺泡沫制备技术开发进展及国内外产品生产现况,综述了三聚氰胺的非声学参数测定,泡沫吸音性能、吸附性能、阻燃、隔热性能及其应用,并对国外将三聚氰胺泡沫用于航空航天、汽车和轨道车辆等领域的研究作了报道。     

聚酰亚胺的合成和应用

简要地介绍了4种聚酰亚胺的聚合法(熔融缩聚、溶液缩聚、界面缩聚及气相沉积法),并对这4种方法进行了比较和评述,对聚酰亚胺的应用作了简要介绍。     

硅橡胶泡沫材料技术及应用

综述了近年来硅橡胶泡沫材料的研究进展, 着重从硅橡胶泡沫材料的制备及发泡机理、功能性硅橡胶泡沫材料以及硅橡胶泡沫材料的应用等方面进行介绍。并指出硅橡胶泡沫有望成为未来发泡材料的发展方向之一。     

Synthesis and characterization of a positive‐working,aqueous‐base‐developable photosensitive polyimide precursor

A positive‐working, aqueous‐base‐developable photosensitive polyimide precursor based on poly(amic ester)‐bearing phenolic hydroxyl groups and a diazonaphthoquinone photosensitive compound was developed. The poly(amic ester) was prepared from a direct polymerization of 2,2′‐bis‐(3‐amino‐4‐hydroxyphenyl)hexafluoropropane and bis(n‐butyl)ester of pyromellitic acid in the presence of phenylphosphonic dichloride as an activator. Subsequently, the thermal imidization of the poly(amic ester) precursor at 300°C produced the corresponding polyimide. The inherent viscosity of the precursor polymer was 0.23 dL/g. The cyclized polyimide showed a glass‐transition temperature at 356°C and a 5% weight loss at 474°C in nitrogen. The structures of the precursor polymer and the fully cyclized polymer were characterized by Fourier transform infrared spectroscopy and ¹H‐NMR. The photosensitive polyimide precursor containing 25 wt % diazonaphthoquinone photoactive compound showed a sensitivity of 150 mJ/cm² and a contrast of 1.65 in a 3 μm film with 1.25 wt % tetramethylammonium hydroxide developer. A pattern with a resolution of 10 μm was obtained from this composition. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 352–358, 2002