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中科院广州化学所采用2,4-甲苯二异氰酸酯、聚醚多元醇和107硅橡胶等原料首先制取端-NCO有机硅改性聚氨酯预聚体,然后加入N-苯基-δ-氨丙基三甲氧基硅烷(Y-9669),于50-70oC反应2h,得到硅烷化聚氨酯预聚体;再添加适量的填料和助剂,配制出端硅烷化聚氨酯(STPU)密封胶。该密封胶综合性能优异、韧性好且强度高; 相似文献
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设计合成含胺类和烷氧基硅烷类官能基团的3种新型胺类封端剂,分别为N-苯亚甲基-3-三乙氧基硅烷基-1-丙胺(Imine-TEOS)、N-对二甲氨基苯亚甲基-3-三乙氧基硅烷基-1-丙胺(Imine-DTEOS)和N-苯亚甲基-3-三(甲氧基乙氧基乙氧基)硅烷基-1-丙胺(Imine-GLYME),将其应用于阴离子聚合物的封端反应合成末端官能化聚苯乙烯(PS)和聚丁二烯(PB),并对其结构进行表征。结果表明:封端剂能与聚苯乙烯基锂进行等物质的量封端反应,成功实现封端反应制备官能化PS和PB,封端剂不会引发副反应。 相似文献
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以聚醚二元醇(DL-1000)、4,4′-二苯基甲烷二异氰酸酯(MDI)为主要原料合成端-NCO基PU(聚氨酯)预聚体;然后以γ-氨丙基三乙氧基硅烷(KH-550)对其进行嵌段共聚改性,并以3,3′-二氯-4,4′-二氨基二苯基甲烷(MOCA)/蓖麻油作为复合固化剂,制备出无溶剂型双组分有机硅改性PU胶粘剂。研究结果表明:硅烷键已引入PU胶粘剂中;随着KH-550含量的不断增加,胶粘剂的黏度增大、固化时间缩短、室温剪切强度下降且耐热性增强;通过调节不同KH-550含量,可制备出不同性能要求的胶粘剂;该胶粘剂的玻璃化转变温度(-45.9℃)相对较低,说明其耐寒性相对较好。 相似文献
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采用烷氧基硅烷对α,ω-二羟基聚二甲基硅氧烷(107硅橡胶)进行改性制得烷氧基封端107硅橡胶,考察了封端反应催化剂种类和用量、封端剂种类、封端时反应温度和反应时间对封端效果的影响,并测试了烷氧基封端107硅橡胶作基础聚合物时有机硅密封胶的性能。结果表明,采用烷氧基硅烷对107硅橡胶进行封端时的较佳条件为:催化剂选择0.01份KOH碱胶,封端剂选择甲基三甲氧基硅烷、乙烯基三甲氧基硅烷或乙烯基三乙氧基硅烷中的一种,反应温度80℃,反应时间60 min。此条件下107硅橡胶的端羟基已基本反应完全,后续制胶过程中无黏度高峰。采用烷氧基封端107硅橡胶作基础聚合物的有机硅密封胶在95℃养护16 h后力学性能保持率较高,贮存稳定性良好,不发生黄变。 相似文献
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Polyurethanes obtained from 4,4′‐diphenylmethane diisocyanate (MDI) and polydiols with different molecular weights (polyethylene glycol and polyoxypropylene diols) were used as modifiers for diglycidyl ether of bisphenol A. Impact strength (IS), critical stress intensity factor (KC), flexural strength and flexural strain at break were measured as a function of polyurethane (PUR) type and content. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and infrared spectroscopy (FTIR) were employed for the structure and morphology analysis. It was found that the addition of polyurethane with an excess of isocyanate groups to epoxy resin resulted in the formation of a grafted interpenetrating polymer network structure. The mechanical properties of epoxy resin were improved with 5 and 10% PUR. Moreover, it was observed that composites containing PUR based on higher molecular weight (PUR 1002 and PUR 2002) with long flexible segments exhibited higher impact strength while PUR prepared from polyethylene glycol had a higher flexural energy to break and a higher flexural modulus. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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采用不同方法[包括EP(环氧树脂)的pH值调节法、EP中添加改性剂法和改性剂吸附包覆纳米TiO2法等]对纳米TiO2在EP中的分散性进行了研究。结果表明:上述改性方法均能促进纳米TiO2在EP中良好分散:当EP的pH值为3时,相应胶粘剂的剪切强度比pH值未调节体系提高了11.46%;采用EP中添加改性剂法,并且当改性剂为SDBS(十二烷基苯磺酸钠)时,相应胶粘剂的剪切强度比无改性剂体系提高了6.7%;采用改性剂吸附包覆纳米TiO2法,并且当改性剂为SDS(十二烷基磺酸钠)、KH-560(硅烷偶联剂)和SDBS时,相应胶粘剂的剪切强度比无改性剂体系分别提高了41.7%(SDS)、16.4%(KH-560)和9.4%(SDBS)。 相似文献
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为进一步改善第二代双组分丙烯酸酯胶粘剂(SGA)韧性差、耐冲击性欠佳等缺点,采用硅烷偶联剂(KH-570)对纳米Al2O3(nano-Al2O3)表面进行改性,并将改性nano-Al2O3以物理高速剪切方式引入体系中,配制高性能的SGA。研究结果表明:当w(KH-570)=3.5%、水解时间为1.0 h时,KH-570对nano-Al2O3的改性效果最佳;当w(改性nano-Al2O3)=3%时,相应SGA的增强增韧效果最佳,其剪切强度>27 MPa、冲击强度>28 kJ/m2且胶液透明性良好。 相似文献
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以丙烯酸-2-羟基乙酯(HEA)、γ-缩水甘油醚氧丙基三甲氧基硅烷(KH-560)和正硅酸乙酯(TEOS)为主要原料,制备了两种加成型有机硅灌封胶用粘接增强剂。采用红外光谱(FT-IR)法对其结构进行了表征,并探讨了两种粘接增强剂对灌封胶及其铝基胶接件的剪切强度、黏度、拉伸强度、断裂伸长率和硬度等影响。结果表明:粘接增强剂的引入能明显提高灌封胶的粘接性能,其中含环氧基粘接增强剂的增强效果相对较好;当w(含环氧基粘接增强剂)=0.6%(相对于灌封胶总质量而言)时,灌封胶的剪切强度(1.21 MPa)比无粘接增强剂体系提高了570%左右。 相似文献
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以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和丙烯腈(AN)为主要原料,γ-(甲基丙烯酰氧基)丙基三甲氧基硅烷(KH-570)为改性剂,采用半连续种子乳液二阶段聚合法制备出一种核/壳结构型硅丙乳液。研究结果表明:KH-570含量对胶膜吸水率影响较小;胶膜力学性能及其保持率随KH-570含量增加而增大;当w(KH-570)=5%(相对于单体总质量而言)时,乳液及其胶膜的综合性能相对最好,其吸水率、拉伸强度和断裂伸长率分别为6.92%、13.37 MPa和43.98%,吸水48 h后拉伸强度和断裂伸长率分别为12.01 MPa和40.02%,吸水48 h后拉伸强度和断裂伸长率的保持率分别为89.83%和91.41%。 相似文献
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以多元醇(PPG-2000或PTMG-2000)、甲苯二异氰酸酯(TDI)为主要原料,合成了PU(聚氨酯)预聚体;然后加入E-44型EP(环氧树脂)和缩水甘油醚(Glycidyl)对PU预聚体进行封端,制成E/G-PU(端环氧基PU);再加入TDE-85型EP和活性稀释剂,制备出环保无溶剂型E/G-PU/TDE-85/活性稀释剂胶粘剂;最后采用间苯二甲胺(m-XDA)固化剂和2,4,6-三(二甲胺基甲基)苯酚(DMP-30).促进剂对该EP胶粘剂进行固化,明显提升了体系的固化速率。结果表明:当w(活性稀释剂D-085)=5%时,E/G-PU(PTMG-2000)/TDE-85/D-085胶粘剂的剪切强度(24.63 MPa)相对最大。 相似文献
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Liquid‐type nucleating agent for improving thermal insulating properties of rigid polyurethane foams by HFC‐365mfc as a blowing agent 下载免费PDF全文
The effects of liquid‐type additives on the morphology, thermal conductivity, and mechanical strength of polyurethane (PUR) foams were investigated. The PUR foams synthesized with perfluoroalkane showed a smaller average cell diameter and a lower thermal conductivity than PUR foams prepared with propylenecarbonate or acetone. The average cell diameter of the PUR foams decreased from 228 to 155 μm and the thermal conductivity decreased from 0.0227 to 0.0196 kcal/mh °C when the perfluoroalkane content was 0.0 to 2.0 php (parts per hundred polyol by weight). The perfluoroalkane likely acted as a nucleating agent during the formation of the PUR foams. The addition of perfluoroalkane induced the smaller cells size of the PUR foams probably due to lower surface tension of the polyol and perfluoroalkane mixture, resulting in high nucleation rate. The smaller cell size appears to be the main reason for the improvement in the thermal insulating and the mechanical properties of these PUR foams. The compressive strength of the PUR foams prepared with perfluoroalkane was higher than the PUR foams prepared with the propylenecarbonate and acetone. Based on the morphology, thermal conductivity, and compressive strength, it is suggested that the perfluoroalkane is an efficient liquid‐type additive for the improving the thermal insulation of PUR foams. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43557. 相似文献