共查询到18条相似文献,搜索用时 125 毫秒
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以六甲基二硅氧烷(MM)、四甲基二乙烯基二硅氧烷、硅酸乙酯为原料,异丙醇为溶剂,盐酸为催化剂,通过受控水解反应合成了不同乙烯基含量的MQ硅树脂。并表征了产物的性能。结果表明,所合成的MQ硅树脂具有良好的热稳定性,其质量损失率为5%时的热分解温度在276~389℃之间;随着乙烯基含量的增加,MQ硅树脂的热稳定性下降;甲基MQ硅树脂在DSC第一次升温过程中存在熔融峰70.6℃,表明具有一定程度的结晶性。 相似文献
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以正硅酸乙酯和六甲基二硅氧烷为原料制得MQ硅树脂,MQ硅树脂再与107硅橡胶进行缩合反应,制备了107-MQ;再加入过氧化苯甲酰(BPO)及辅料配成有机硅压敏胶。考察了MQ硅树脂与107硅橡胶的质量比、BPO用量、外加辅料对压敏胶性能的影响。较佳工艺为:MQ与107硅橡胶的质量比为0.75:1.1.75:1、BPO用量2份、丙烯酸羟乙酯用量0.5份(MQ与107硅橡胶总用量100份),此时有机硅压敏胶液稳定,可长时间放置,初粘32#钢球,剥离强度12N/25mm。 相似文献
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甲基乙烯基MQ硅树脂的制备工艺研究 总被引:1,自引:0,他引:1
以1,3-二乙烯基-1,1,3,3-四甲基二硅氧烷和正硅酸乙酯为主要原料,以浓盐酸为催化剂制备了甲基乙烯基MQ硅树脂,并对其工艺条件进行了研究,结果表明,其适宜的制备工艺条件为:催化剂(35-38%盐酸浓盐酸)、去离子水、乙醇的用量分别为1.1%、11%、22%(体积百分数),水解反应时间1h,反应温度在75℃-80℃之间。 相似文献
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MQ树脂对加成型RTV有机硅灌封胶补强性能研究 总被引:2,自引:0,他引:2
采用正硅酸酯水解法制备了含乙烯基单元的MQ树脂、含二官能团D单元的MDQ树脂和含三官能团T单元的MTQ树脂,并以此作为加成型RTV(室温硫化)有机硅灌封胶的补强填料。研究了MQ树脂用量、M/Q值和乙烯基含量等对含阻燃剂和导热填料的加成型RTV有机硅灌封胶性能的影响。结果表明:三种树脂均能有效改善灌封胶的力学性能,同时对胶料黏度影响不大;当MQ树脂中M/Q值为0.6、w(乙烯基)=6.8%和w(MQ树脂)=7%时,灌封胶的增强效果相对最好;当MmDdQq树脂中n(d)∶n(m+d+q)=10∶100或MmTtQq树脂中n(t)∶n(m+t+q)≈20∶100时,灌封胶具有相对较好的增强效果。 相似文献
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MQ silicone resins, which represent a broad range of hydrolytic condensation products of monofunctional silane (M) and tetrafunctional silane (Q), were synthesized by reaction of water glass with hexamethyldisiloxane. The optimum reaction time and the optimal reaction temperature is 30 min and 30–40°C, respectively. Concentrated hydrochloric acid is the best one among those catalysts tested. In large-scale experiments (420–1680 mL), the favorable feeding order is catalyst first, and then water glass, the mixture of hexamethyldisiloxane and ethanol last and most MQ silicone resin was observed. The structure of MQ silicone resin was characterized by FT-IR and GPC spectra. The MQ silicone resin shows narrow molecular weight distribution and the number average molecular weight of MQ silicone resin is 2917. The silicone pressure sensitive adhesive prepared from as-synthesized MQ resin has good tack (29#) and 180° peel adhesion (5.630N/20 mm). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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正硅酸乙酯水解可得有机硅聚合物,但产物分子量不高,成膜性差。用环氧树脂对其改性,制得物的涂膜成膜性优良,且大大缩短固化时间。研究了水解温度与时间,催化剂种类,溶剂用量和环氧树脂用量、反应温度与时间对改性物的影响。结果表明,水解温度50℃,时间3h,硫酸催化,乙醇用量35%,环氧树脂用量20%~50%,反应温度50℃,反应时间1h,涂膜性能优良。 相似文献
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《Ceramics International》2020,46(4):4870-4877
SiO2–C precursors with various surface areas were derived from tetraethyl orthosilicate and phenolic resin as Si and C sources, respectively, by a modified sol–gel process using the in situ precipitation of phenol resin in a prepared wet gel. The surface area of the SiO2–C precursors was varied from 20 to 175 m2/g by changing the C/Si molar ratio in the preform. β-SiC powders were synthesized using carbothermal reduction in vacuum at the temperature range of 1200–1600 °C. The effects of the temperature and heat treatment time as well as that of the surface area of the preform on the formation of β-SiC powders were studied. It was determined that the formation of β-SiC started at 1200 °C and was considerably promoted as the heat treatment temperature and time further increased during the carbothermal reduction of SiO2–C preforms with high surface area. When high surface area SiO2–C preforms were used, highly crystalline SiC powders were synthesized at 1600 °C in vacuum with a high yield of 85%. 相似文献
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加成型纺织商标用液体硅橡胶的配方设计 总被引:1,自引:0,他引:1
以D4或DMC、乙烯基双封头、乙烯基环体等为原料,以四甲基氢氧化铵为催化剂合成了不同摩尔质量的乙烯基硅油;以高舍氢硅油、舍氢双封头、六甲基二硅氧烷、D4合成实验所需的交联剂低舍氢硅油;以白炭黑、乙烯MQ树脂为补强填料,以二甲基硅油为稀释剂制备纺织商标用透明液体硅橡胶。分别探讨了乙烯基硅油的粘度、白炭黑的比表面积和用量、乙烯MQ树脂的用量、二甲基硅油用量与铂金络合物和抑制剂的用量、固化(硬化)剂的用量对纺织商标用液体硅橡胶物理力学和加工工艺性能的影响。实验表明,所制备的纺织商标用透明液体硅橡胶在物理力学和加工工艺性能上基本达到甚至超出国内外同类产品。 相似文献
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以乙醇为溶剂,将正硅酸乙酯(TEOS)与乙烯基三乙氧基硅烷(VTEOS)经酸催化合成了一种表面带有乙烯基的活性二氧化硅粒子,然后将其与丙烯酸树脂聚合得到透明的有机硅改性阳极电泳漆。研究了有机硅的添加方式对反应过程,有机硅含量对改性丙烯酸树脂的玻璃化转变温度、黏度以及电泳漆性能的影响,采用傅里叶变换红外光谱、差示扫描量热和热重分析等对改性丙烯酸树脂进行了表征。结果表明,有机硅的最佳添加方式是与部分单体预混后逐滴滴加。随着有机硅含量的增大,改性丙烯酸树脂的黏度、玻璃化转变温度和耐热性提高。当有机硅添加量为0.8%~1.2%时,电泳漆膜的综合性能较好。 相似文献