共查询到19条相似文献,搜索用时 119 毫秒
1.
2.
以苯胺、苯酚和多聚甲醛为原料,采用无溶剂法合成了BZ(苯并噁嗪)预聚体;然后将BZ预聚体进行一般固化和定向固化,并着重探讨了不同固化方式对固化产物[即PBZ(聚苯并噁嗪)]热稳定性的影响。研究结果表明:固化温度和固化方式对PBZ的热稳定性影响较大。180℃一般固化的聚合物之热稳定性相对最高,其热失重5%时的对应温度为291℃;160℃定向固化的聚合物之热稳定性相对最高,其热失重5%时的对应温度为341℃;对同样的BZ预聚体而言,160℃定向固化的聚合物之热稳定性优于180℃一般固化的聚合物。 相似文献
3.
以含磷中间体(BPPP)、苯胺和甲醛溶液为原料合成了一种新型含苯磷苯并噁嗪单体,通过H谱(1H-NMR)和傅里叶红外光谱(FT-IR)对其化学结构进行了表征,利用差示扫描量热仪和热重分析仪分别研究了其热固化行为及聚合物的热稳定性.结果表明:含苯磷苯并噁嗪的固化过程从135℃开始放热,到261℃放热结束,固化峰值温度为226.5℃;含苯磷苯并噁嗪在不添加任何催化剂的情况下能完全聚合,而且该聚合物具有很好的热稳定性. 相似文献
4.
以苯酚/苯胺型苯并噁嗪和苯酚/4,4'–二苯甲烷二胺型苯并噁嗪为参照对象,通过DSC、TGA和TGA-FTIR联用测试,研究了酚羟基对位连有不同电子效应的取代基时,苯并噁嗪中间体开环聚合及其聚合物热稳定性的变化。结果表明,酚羟基对位氯原子的取代降低了苯并噁嗪中间体开环聚合的温度,而甲基的取代使苯并噁嗪中间体开环聚合的温度升高;由于氯原子的吸电子效应导致聚苯并噁嗪Mannich(曼尼希)桥上的C—N和C—C键被削弱,使得其热稳定性下降;甲基的取代使聚苯并噁嗪的交联密度下降,因而也降低了其热稳定性。 相似文献
5.
6.
7.
高性能苯并噁嗪模压复合材料的研究 总被引:2,自引:0,他引:2
利用不同苯并噁嗪树脂体系胶液浸渍短切玻璃纤维,制得苯并噁嗪模塑料,并热压成型.通过对各树脂体系升温黏度变化、DSC固化行为以及凝胶化时间的研究,表明胺类催化剂或环氧-胺类催化剂的加入明显降低了苯并嗯嗪的热固化温度,提高了体系反应活性.对模压制品弯曲性能和耐热性能进行表征,得出加入环氧-胺类催化剂的苯并噁嗪体系,弯曲强度和弯曲模量分别达到565 MPa和22.7 GPa,明显高于普通酚醛、聚酯模压材料,玻璃化转变温度达到195℃,具有较好耐热性.模压制品的弯曲断面观察结果显示玻纤被树脂良好浸渍,纤维树脂间显示了良好的黏结性. 相似文献
8.
苯并噁嗪及其碳纤维复合材料固化动力学研究 总被引:2,自引:0,他引:2
采用非等温DSC技术研究了不同升温速率下苯并口恶嗪/碳纤维复合材料的固化过程。以Avrami方程分析计算了2种固化体系的动力学参数和表观反应活化能。结果表明:Avrami指数n随固化温度的变化能反映出苯并口恶嗪固化过程的2个阶段———凝胶粒子形成和增长阶段及扩散控制阶段。用Avrami速率常数计算得到的表观活化能与文献值基本一致,但能更清楚地反映出碳纤维对苯并口恶嗪固化反应动力学的影响,即催化作用和延缓作用。 相似文献
9.
苯并噁嗪树脂作为一种20世纪90年代出现的新型热固性树脂,因其优异的热性能、力学性能、尺寸稳定性以及灵活的分子设计性等受到学术界和工业界的广泛关注。目前,它已经在航空航天、运输、石油天然气、电子制造等多领域得到应用。然而,一直以来苯并噁嗪树脂的发展大多与石油基的化学品有关。持续增长的全球能源危机、环境问题促使研究者们开始转向自然界中寻找原料。天然可再生原料的结构多样性和独特功能使其成为高性能苯并噁嗪树脂的强有力候选者。本文重点介绍了近年来利用可再生的酚类原料制备苯并噁嗪树脂的研究进展。另外,也简单概述了生物质胺源在苯并噁嗪树脂领域的应用。最后,对未来生物基苯并噁嗪树脂的发展方向进行了展望。 相似文献
10.
11.
将无水CuCl2、无水AlCl3、无水FeCl3、无水MnCl2,无水MgCl2和无水ZnCl2加入到双酚A-苯胺型聚苯并恶嗪中,通过红外光谱(FTIR),核磁共振氢谱(1H-NMR),热失重分析(TGA)和元素分析等手段,研究了加入金属盐对聚苯并恶嗪热稳定性的影响及作用机理。结果表明,加入金属盐后聚苯并恶嗪的热稳定性均有不同程度的提高。无水MnCl2、无水ZnCl2和无水MgCl2配位能力较弱,苯并恶嗪主要发生热固化反应生成酚羟基邻位Mannich桥结构。无水CuCl2、无水AlCl3和无水FeCl3配位能力较强,能催化苯并恶嗪生成较多的苯胺对位Mannich桥结构。正是固化物中较多的苯胺对位连接结构,有效抑制了高温下苯胺衍生物的形成和挥发,从而赋予了聚苯并恶嗪更高的热稳定性。 相似文献
12.
The effect of a range of organic additives on the thermal stability of poly(vinyl chloride), both with and without a chloroparaffin extender, was studied using a number of experimental techniques. Of the additives used the best overall balance was provided by pentaerythritol, which increased stability when the extender was present and had no effect when it was absent. The congo red test emerged as the most suitable technique, being consistent and inexpensive and able to screen several additives simultaneously. Isothermal differential thermal analysis correlated with the congo red test but required more expensive equipment, was time-consuming and demanded good mixing of the poly(vinyl chloride) compound to give reproducible results. Thermogravimetry was not sufficiently sensitive and the heat stability test was the least useful of all. 相似文献
13.
讨论了在120℃条件下保温40h,添加不同剂量的稳定剂苯二甲酰氯,对顺酐熔融色度(铂-钴色号)ASTM的影响。该实验确定顺酐熔融色度稳定剂苯二甲酰氯的最佳添加质量分数为10×10-6,可保证120℃下保温40h时铂-钴色号40号,满足生产及市场需求。 相似文献
14.
15.
采用酯交换缩聚法,以聚四氢呋喃醚二醇(PTMEG)和1,6-六亚甲基二氨基甲酸甲酯(HDU)为原料,以1,4-丁二醇(BDO)为扩链剂,以二丁基氧化锡为催化剂制备脂肪族聚醚型聚氨酯(PU)弹性体。用TGA和FTIR考察聚氨酯弹性体的热降解机理及原料组成对聚氨酯热降解过程的影响。结果表明:聚氨酯弹性体的热降解过程包括两个阶段,分别为硬段(氨基甲酸酯)和软段(聚醚多元醇)的降解,其中硬段(氨基甲酸酯)的降解主要降解产物为碳化二亚胺、CO2、四氢呋喃及水,软段(聚醚多元醇)的降解主要产物为四氢呋喃和水。随着硬段含量的降低,聚氨酯弹性体初始热降解温度由282℃上升至327℃,聚氨酯弹性体的热稳定性升高。 相似文献
16.
Wenkai Zhang Xiuxiu Gao Lili Yu Yanrong Ren Hao Xu Baoying Liu Yanpeng Wang Xiaomin Fang Yuanqing Xu Tao Ding 《Polymer International》2017,66(6):908-915
A benzoxazine with siloxane and phenyl sulfone units (BS ‐b) was synthesized by using aminopropyltriethoxysilane, 4,4'‐dihydroxydiphenylsulfone and paraformaldehyde as precursors via Mannich condensation. Then the hydrolysis and polycondensation reactions of siloxane units were performed and benzoxazine bearing polysiloxanes (BS‐PSO ) were obtained. The ring‐opening polymerization reactions of both BS ‐b and BS‐PSO were studied by Fourier transform IR spectroscopy and DSC in non‐isothermal conditions. The kinetics of the polymerization of BS ‐b were found to be well described by using an n th‐order kinetic model for n = 0.7 (activation energy 141 kJ mol?1). The BS‐PSO was also used to modify bisphenol‐A‐based benzoxazines (BA ‐a), and the morphological structure and thermal properties of the copolymer were investigated. The TGA results indicate that the silane‐functional polybenzoxazines display enhanced initial decomposition temperature and char yields in comparison with poly(BA ‐a). These results are believed to be important for the development of new flame‐retardant laminates. © 2017 Society of Chemical Industry 相似文献
17.
Zinc glycerolate (ZnGly) was prepared and used as a poly(vinyl chloride) (PVC) thermal stabilizer in this work. ZnGly was characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), thermogravimetry (TGA), and transmission electron microscopy (TEM). Visual color evolution and thermal stability time at 180°C were used to examine the stabilizing efficiency of the samples. The thermal stability of PVC was significantly enhanced through adding ZnGly or ZnGly with lanthanum stearate (LaSt3). Compared with zinc stearate (ZnSt2), it was demonstrated the initial color stability was markedly improved and the thermal stability time was obviously extended by adding ZnGly. The thermal stability time of ZnGly was threefold than ZnSt2. In comparison with CaSt2/ZnSt2, the extent of coloration of PVC samples was significantly inhibited though adding LaSt3/ZnGly. It was verified that the appropriate percents of ZnGly in the mixture were between 25 and 50%. A possible mechanism for the stabilizing efficiency of ZnGly was also proposed. The stabilizing efficiency was attributed to the stabilizer's ability to absorb hydrogen chloride and replace the labile chlorine atoms on PVC chains. Moreover, the dynamic thermogravimetric analysis was used to confirm that combination of LaSt3 with ZnGly presented an obvious improvement of stability on thermal degradation of PVC. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
18.
19.
对比分析了3批聚合度为1000的聚氯乙烯(PVC)树脂的热稳定性、相对分子质量及其分布、偏二氯乙烯链节含量、分子链双键的相对含量及重金属离子含量.结果发现,热稳定性差的树脂双键相对含量较高,重金属离子相对含量明显高出正常批次料;同时还检测出了偏二氯乙烯链节.研究认为,引起配混料和医用粒料颜色发暗、雾度升高、制品黄色指数高的主要原因首先是树脂重金属离子含量高,对树脂老化起到了催化作用;其次是原料单体中的杂质参与了聚合,形成了分子链缺陷,导致热稳定性下降. 相似文献