共查询到17条相似文献,搜索用时 78 毫秒
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热塑性聚酰亚胺微电子薄膜的制备 总被引:2,自引:0,他引:2
以微电子业所急需的聚酰亚胺薄膜为背景,采用一种热塑性聚酰亚胺树脂(TPI),实验测定了聚合物溶液特性、干燥工艺及热拉伸性能。在化学环化过程中聚合物溶液粘度随时间逐步增大;15 h后粘度和重均相对分子质量及分布趋于稳定。薄膜溶剂含量在干燥初期急剧下降,干燥速率随干燥温度升高而增大。TPI树脂表现出良好的热塑拉伸性能,当温度高于其玻璃化温度时,最大拉伸比随升温速率降低而增大,而随拉伸载荷增加呈现出先增后降。TPI薄膜经拉伸处理后其力学性能得到明显提高,综合性能与日本钟渊TP E薄膜相当。 相似文献
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以2,3,3',4'-二苯醚四甲酸二酐(a-ODPA)为单体,与不同配比的4,4'-二氨基二苯醚(4,4'-ODA)和1,4-苯二胺(1,4-PDA)共聚,制备了一系列的聚酰亚胺(PI)。结果表明,随着1,4-PDA摩尔分数的增加,Tg(玻璃化转变温度)从279℃逐渐上升到328℃,同时比浓对数黏度从110 mL/g逐渐下降到40 mL/g(DMAc,25℃)。当1,4-PDA的摩尔分数不超过0.4的时候,该PI在DMAc、DMF、NMP、DMSO和γ-丁内酯中具有良好的溶解性,塑料样条在220℃的高温下,力学性能的保持率良好。 相似文献
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Jie Sun Xiaoyan Shu Yu Liu Haobin Zhang Xiaofeng Liu Yan Jiang Bin Kang Chao Xue Gongbao Song 《Propellants, Explosives, Pyrotechnics》2011,36(4):341-346
The CTE and the theoretical density are important properties for energetic materials. To obtain the CTE and the theoretical density of 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), XRD, and Rietveld refinement are employed to estimate the dimensional changes, within the temperature range from 30 to 170 °C. The CTE of a, b, c axis and volume are obtained as 3.07×10−5 K−1, 8.28×10−5 K−1, 9.19×10−5 K−1, and 20.7×10−5 K−1, respectively. Calculated from the refined cell parameters, the theoretical density at the given temperature can be obtained. The theoretical density at 20 °C (1.7994 g cm−3) is in close match with the RDX single‐crystal density (1.7990 g cm−3) measured by density gradient method. It is suggested that the CTE measured by XRD could perfectly meet with the thermal expansion of RDX. 相似文献
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霞石微晶玻璃热膨胀系数的研究 总被引:1,自引:0,他引:1
霞石微晶玻璃热膨胀系数的研究刘小波(湘潭矿业学院411201)StudyonThermalExpansionCoefficientofNephelineGlass-Ceramics¥LiuXiaobo(XiangtanMiningInstitute)... 相似文献
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Dimensional changes related to temperature cycling of the β and δ polymorphs of HMX (octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine) are important for a variety of applications. The coefficient of thermal expansion (CTE) of β and δ phases are measured over a temperature range of −20 °C to 215 °C by thermo‐mechanical analysis (TMA). Dimensional changes associated with the phase transition were also measured, and the time‐temperature dependence of the dimensional change is consistent with phase transition kinetics measured earlier by differential scanning calorimetry (DSC). One HMX sample measured by TMA during its initial heating and again three days later during a second heating showed the β‐to‐δ phase transition a second time, thereby indicating back conversion from δ‐to‐β phase HMX during those three days. DSC was used to measure kinetics of the δ‐to‐β back conversion. The most successful approach was to first heat the material to create the δ phase, then after a given period at room temperature, measure the heat absorbed during a second pass through the β‐to‐δ phase transition. Back conversion at room temperature follows nucleation‐growth kinetics. 相似文献
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偶联剂处理玻纤改性热塑性聚酰亚胺 总被引:2,自引:0,他引:2
分别选用KH550、KH560、KH570三种有机硅烷偶联剂处理无碱玻纤粉(GF),采用热模压成型技术制备玻纤增强聚酰亚胺复合材料,对复合材料的力学性能进行了分析和研究。结果表明:以KH550处理30%玻纤得到的复合材料力学性能最好,当其用量为GF质量的0.5%时,拉伸强度提高了35%,弹性模量提高了21.8%,弯曲强度提高了42.1%,冲击强度提高了52.5%。SEM显示KH550处理GF与聚酰亚胺基体之间形成了良好的界面,界面层起到很好的应力传递作用,达到良好的增强、增韧效果。 相似文献
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热塑性聚酰亚胺复合材料导热性能研究 总被引:5,自引:0,他引:5
采用稳态热板法测定铜粉(Cu)填充热塑性聚酰亚胺(TPI)复合材料的热导率,研究了Cu填充量对复合材料的力学性能和导热性能的影响,初步探讨了温度与复合材料热导率的关系。通过扫描电子显微镜观察了复合材料的微观形态。在此基础上,理论计算复合材料热导率。研究表明,Cu填充TPI可有效提高复合材料力学性能和导热性能。当Cu体积分数提高到26%时,填料聚集形成导热链,Cu/TPI复合材料的热导率是纯TPI树脂的3.5倍;当填料含量低于10%时,Maxwell—Eucken模型适合预测复合材料热导率;基于导热链考虑的Y.Agan模型可较好地反映复合材料热导率随填料含量的变化情况;随着温度的升高,Cu/TPI复合材料热导率先增大后趋于平缓。 相似文献
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利用PVT分析仪测定PS的热膨胀系数,等温压缩系数和热压系数 总被引:2,自引:0,他引:2
利用实验测得的PVT数据直接计算出聚苯乙烯(PS)的热膨胀系数α,等温压缩系数β和热压系数γ随温度和压力的变化关系,与同样从PVT数据获得的Tait方程计算出的α、β和γ结果比较,说明了Tait方程在使用上存在一定的局限性。 相似文献