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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/3580

    Title: 氰酸酯/聚氧化二甲苯摻合體反應性及相行為研究
    Authors: 周凱茹;Kian-Run Chou
    Contributors: 化學工程與材料工程研究所
    Keywords: 相分離;摻合;聚氧化二甲苯;氰酸酯;反應動力;phase separation;blend;PPO;cyanate ester
    Date: 2000-06-16
    Issue Date: 2009-09-21 12:18:20 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 本研究以DSC來探討不同組成份的聚氧化二甲苯與氰酸酯摻合體反應性。由DSC實驗得知,摻合體的反應起始溫度隨著PPO含量增多而降低,且反應之總放熱量也隨著PPO量增多而下降。FTIR的分析也發現,特性官能基的反應隨著PPO增加而加速,此外氰酸酯會與PPO的末端OH基反應產生中間產物(imidocarbonate)。氰酸酯?聚氧化二甲苯摻合體系統的反應速率高於純氰酸酯系統,原因是由於PPO末端的OH基會催化氰酸酯的硬化反應。氰酸酯?聚氧化二甲苯系統的硬化遵守Kamal的自催化模式,其中包含k1、k2、m、n四個參數,達玻璃態前反應屬於reaction control,Kamal所提的模式可描述得很好;反應後期分子量增大,系統屬diffusion control,自催化模式偏離實驗值。將Kamal的自催化模式加入一擴散因子diffusion factor f(α),則可完整的描述整個實驗過程。氰酸酯?聚氧化二甲苯摻合體屬於反應誘導相分離,SEM發現摻合體相型態與聚氧化二甲苯的含量有關。PPO含量低時(10phr和20phr),相分離是經由nucleation and growth(NG)進行;PPO含量高時(30phr和50phr),相分離是經由spinodal相分離模式(SD)進行。在TGA的分析中,由於PPO的加入會降低摻合體的交聯密度,使得起始裂解溫度隨著PPO含量增加而些微下降。高溫熱穩定性也隨著PPO含量增加而下降。 Cure behavior of cyanate ester and its blends with polyphenylene oxide(PPO)of various compositions were studied using differential scanning calorimetry(DSC)and FTIR. The reaction rates of the cyanate ester blends were found to be higher than that of the neat cyanate ester , and the total heat of reaction decreased with increasing PPO. The effects of PPO content on the cure behavior in the cyanate ester/PPO blends were investigated with FTIR. FTIR analysis reveals that the cyanate functional group reactions are accelerated by adding PPO. This is caused by the reaction of cyanate ester with PPO phenolic end-group and water yielding imidocarbonate and carbamate intermediate which can react with cyanate ester to form cyanurate. The experimental data, showing an autocatalytic behavior, were compared with the model proposed by Kamal, which includes two rate constants, k1 and k2, and two reaction orders, m and n. This model gives a good description of cure kinetics up to the onset of vitrification. With the inclusion of a diffusion factor (f(a)) into this model, it was, however, possible to predict with precision the cure kinetics over the whole range of conversion. During cure , the phase separation induced by the step-growth polymerization of the monomer. The fracture surface of blends was examine using scanning electron microscopy(SEM). At low PPO content(10 and 20phr), the phase separation takes place via nucleation and growth (NG). At high PPO content(30phr and 50phr), the phase separation takes place via spinodal decomposition (SD). The results from TGA weight loss profiles indicate that onset decomposition temperature was decreased by the incorporation of PPO. This is caused by that the presence of PPO lowers crosslink density of cyanate ester blends. High-temperature stability decreased with increasing PPO.
    Appears in Collections:[化學工程與材料工程研究所] 博碩士論文

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