【作者】 李红霞；

【导师】 孟焱；

【作者基本信息】 北京化工大学 ， 化学， 2018， 硕士

【摘要】 环氧树脂具有优异的综合性能,广泛应用于航空航天、电子电气、机械制造及化工防腐等领域。用途的多样性也对环氧材料在复杂使用环境中的使用稳定性提出了挑战。在本论文中,制备并优化了聚醚型超支化环氧(EHBPES),并把它作为全能增韧剂添加到DGEBA环氧-胺固化体系中,全面提升了各项性能。研究了该杂化体系的反应动力学和性能并重点对其物理老化及耐湿热性能进行了研究。论文主要内容如下:1、以二甲基乙酰胺(DMAC)为溶剂,用A2+B3法在较低温度(130℃)下合成了分子量分布更窄的聚醚型超支化分子HBPES,研究了反应时间、单体配比、共催化剂(KI)添加及反应器放大对分子量及其分布和产率的影响,获得了优化的制备条件。在1 L反应瓶中加入3:4(A2:B3)单体和1%KI,当反应时间为6h时,可得到分子量分布更窄的HBPES,经端基环氧化可获得目标产物EHBPES(Mn约2500g/mol)。2、分别用三乙烯四胺(TETA)和二氨基二苯砜(DDS)对EHBPES/DGEBA杂化环氧进行了固化,用DSC研究了 EHBPES添加对杂化环氧固化动力学的影响,发现EHBPES添加可提高体系中环氧的反应活性。3、研究了 EHBPES添加量和老化时间对物理老化的影响。结果表明,在相同等当温度(T-Tg)下,添加EHBPES会加速物理老化过程。无论添加量的多少,热焓松弛都在Tg-10℃下最快。在该老化温度下,EHBPES添加量为5%的杂化环氧在老化后的动态力学性能变化最大。正电子湮灭(PALS)测试表明,EHBPES添加会加快物理老化过程中的体积松弛,导致冲击性能更快地下降。4、研究了 EHBPES添加对杂化环氧吸水率的影响,并用DMA和TGA研究了吸水对力学和热性能的影响。结果表明,添加EHBPES会提高材料的吸水率。在纯DGEBA,添加5%和10%EHBPES三个体系中,添加5%EHBPES的体系具有最好的耐湿热性能。更多还原

【Abstract】 Epoxy materials have excellent balanced properties and are widely used in aircraft/aerospace,electrical/electronics,machine building,and anti-corrosion industries.However,the diverse and complex environments in which epoxy materials are used require that they must remain stable and reliable.In this thesis,an epoxide-terminated hyperbranched polyether sulphones(EHBPES)was prepared and optimized,and then added as a multi-purpose modifier to improve various properties of DGEBA/amine curing systems.Effects of EHBPES addition on cure kinetics,mechanical properties and,more importantly,on physical aging and hydrothermal aging behaviors were studied.The main contents of the thesis are as follows.1.HBPES with narrower polydispersity is obtained at relatively low temperature(130℃)via A2+B3 approach with DMAC as the solvent.Effects of reaction time,the monomer ratio,addition of co-catalyst(KI)and size of reactor on molecular weight,polydispersity,and yield were investigated;optimized reaction condition was found.When 3:4(A2+B3)monomer ratio and 1%KI were added into in a 1 L reactor and reacted for 6 h,HBPES with narrower polydispersity can be obtained.The final epoxidized product(EHBPES)shows a Mn of ca.2500 g/mol.2.EHBPES is mixed DGEBA and cured with both triethylenetetramine(TETA)and 4,4’-diaminodiphenyl sulfone(DDS).Effects of EHBPES additon on cure kinetics were studied using DSC,and results show that addition of EHBPES can improve the reactivity of epoxide groups.3.Effects of EHBPES loading and aging temperature on physical aging were investigated.Results show that addition of EHBPES accelerates the physical aging process when compared at the same corresponding state(i.e.,Tg-10℃).Despite the difference in EHBPES loadings,all hybrids show the fastest thermal relaxation at ca.Tg-10℃.At this temperature,the hybrid containing 5%EHBPES shows the most dramatic change in dynamic mechanical properties.Positron Annihilation Lifetime Spectroscopy(PALS)measurements indicate that addition of EHBPES accelerates the volumetric relaxation and thus leads to a faster decrease in toughness.4.Effects of EHBPES addition on water absorption were also evaluated.Changes in mechanical and thermal properties due to water absorption were characterized using DMA and TGA.Results suggest that addition of EHBPES increases water absorption.Among the cured hybrid epoxy systems containing 0%,5%,and 10%EHBPES,the hybrid with 5%EHBPES shows the best resistance to hydrothermal ageing.更多还原