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利用高沸物二硅烷中的甲基氯二硅烷制备无氯Si-C-N陶瓷 总被引:2,自引:0,他引:2
直接法生产甲基氯硅烷的高沸点副产物分离出的甲基氯二硅烷(DS)与八甲基环四硅氮烷反应形成氯硅烷低聚物,经氨解成为聚硅氮烷(PSZ)前躯体,并发现PSZ甲苯溶液为假塑性流体,得到70%(质量)的PSZ甲苯溶液的粘流活化能为18.3kJ/mol。PSZ在1100℃高温裂解后,可得到无氯Si-C—N无定型陶瓷,认为该路线是制备高性能Si—C—N陶瓷的最经济的方法之一。 相似文献
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Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as catalyst.The aqueous solutions of thermo-responsive polycarbonates were investigated by rheological measurements.Steady-state shear measurements reveal that the polycarbonate solutions exhibit shear-thinning behavior and the hydrophilic content has a pronounced effect on the flow behavior of the polycarbonates aqueous solutions.The shear viscosity decreases with increasing poly(ethylene oxide)(PEO) composition.The increase of viscosity with increasing concentration is probably attributed to the formation of stronger network owing to interchain entanglement of PEO block at higher concentration.When the flow curves are fitted to the power law model,flow index is obtained to be less than 1,as exhibiting typical pesudoplastic fluid.The viscoelastic properties of the system also show close dependence on the composition of polycarbonates.Temperature sweep confirms that the multiblock polycarbonates exhibit thermo-responsive properties.For 7% aqueous solution of polycarbonate with composition ratio of EO to PO of 1/1,the sol-gel transition occurs at 37 ℃,which makes the system suitable as an injectable drug delivery system. 相似文献
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Poly(acrylamide-co-sodium acrylate)(PAM/AA-Na) and poly(acrylamide-co-sodium vinylsulfonate)(PAM/VSS-Na) were prepared by inverse emulsion polymerization.The effects of CaCl2 on PAM/VSS-Na or PAM/VSS-Na aqueous solutions were investigated by steady-flow experiments at 25,40,55 and 70 ℃.The results show that the apparent viscosities of both solutions decrease with addition of CaCl2 or increase of temperature and shear rates.PAM/VSS-Na solution has better performance on the salt tolerance,shear endurance and temperature resistance due to containing sulfonic group in the molecules.Ca2+ concentration can affect the viscous activation energy of both solutions and the reason may be that these interactions between Ca2+ and also copolymer molecules are related to temperature and competitive in solution.These results may offer the basic data for searching the flooding systems with the ability of temperature resistance,salt tolerance and shear endurance for tertiary oil recovery. 相似文献
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用环己烷作为连续相,Span80/OP10作为复合乳化剂,KPS-TMEDA作氧化还原引发剂,在室温通过反相乳液聚合法制备了黏均相对分子质量大于700万的丙烯酰胺(AM)与丙烯酸钾(AA-K)的稳定共聚物胶乳,并研究了聚合温度、引发剂浓度、单体浓度及配比对聚合物黏均相对分子质量的影响。反应条件:c(KPS)=1 7×10-3mol/L,c(monomer)=3 5~5 5mol/L,n(AA-K)/n(AM)=0 1,温度20~30℃较适宜。对聚合物胶乳的絮凝及泥浆的应用效果进行了评价,发现效果明显,应用方便。 相似文献
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用4-乙烯基苄基胺与葡萄糖内酯反应合成了4-乙烯苄基葡萄糖酰胺单体(VBG),然后以亚甲基双丙烯酰胺(BisA)为交联剂,与丙烯酰胺(AM)、衣康酸(IA)共聚得到含糖结构的三元共聚水凝胶。用热重分析对水凝胶的稳定性进行了表征。水凝胶的膨胀比随着VBG或IA含量的增加而下降;在低pH值或高pH值时水凝胶的膨胀比下降。随氯化钠浓度的提高,水凝胶的膨胀比下降。随着温度的升高水凝胶的膨胀比出现不同的变化,凝胶中VBG含量的增加,水凝胶的膨胀比随着温度的升高而下降,凝胶中IA含量的增加,水凝胶的膨胀比随着温度的升高反而升高。 相似文献
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疏水缔合聚合物溶液性质的耗散颗粒动力学模拟 总被引:1,自引:0,他引:1
本文利用耗散颗粒动力学模拟方法,研究了疏水缔合聚合物溶液黏度随浓度、温度、剪切程度等条件的变化,并模拟了聚合物在油水体系中的聚集行为。研究发现,疏水缔合聚合物在溶液中表现出类似表面活性剂的聚集行为,其黏度随外界影响因素变化主要是由于溶液中聚合物聚集结构的转变。聚合物浓度较低时,聚合物主要以分子内缔合作用为主;随着浓度的增加,产生分子间缔合,并逐步形成相互交联的空间网络,水珠子的扩散率逐渐变小,体系黏度增加。当温度较低时,体系呈现较多柱状聚集结构,黏度较高;随着模拟温度升高,尺寸较大的棒状聚集体转变为球状聚集体,水珠子扩散率不断增加,体系黏度逐渐降低。随着体系剪切速率的提高,聚合物分子在受力方向上取向趋于一致,分子间缠绕和缔合程度减轻,水珠子扩散率急剧增加,体系黏度降低。另外,疏水缔合聚合物易吸附于油水界面,对油水体系的乳化和相转变产生一定影响。 相似文献
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针对海上S油田地层中胶质和沥青质含量高、稠油粘度大和水驱采收率低的问题,采用双子表面活性剂RB107对S油田稠油进行降粘实验,评价其乳化浓度、聚集形态、界面活性、润湿性和稳定性等,在此基础上通过物理模拟驱油实验考察其驱油性能。结果显示:在油藏条件下,当质量分数为0.3%、油水体积比为50∶50时,可使稠油粘度降低97%,使油水界面张力降至0.165 6 m N/m,说明双子表面活性剂RB107在较低浓度下具有较强降粘性能和界面活性;乳化速度为0.24 m L/min,油水乳状液油珠分散均匀且直径小,说明RB107具有较快的乳化速度和较强的稳定性;RB107溶液与原油基底的接触角为10.8°,说明对油水界面具有较强的润湿性;其可在水驱的基础上提高采收率10.1%,说明RB107对S油田稠油具有良好的降粘效果,可作为S油田稠油的降粘剂。 相似文献