Barabanova Anna I, Afanas'ev Egor S, Molchanov Vyacheslav S, Askadskii Andrey A, Philippova Olga E
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow, Russia.
Physics Department, Moscow State University, 119991 Moscow, Russia.
Polymers (Basel). 2021 Sep 9;13(18):3040. doi: 10.3390/polym13183040.
Epoxy/silica thermosets with tunable matrix (vitrimers) were prepared by thermal curing of diglycidyl ether of bisphenol A (DGEBA) in the presence of a hardener-4-methylhexahydrophthalic anhydride (MHHPA), a transesterification catalyst-zinc acetylacetonate (ZAA), and 10-15 nm spherical silica nanoparticles. The properties of the resulting material were studied by tensile testing, thermomechanical and dynamic mechanical analysis. It is shown that at room temperature the introduction of 5-10 wt% of silica nanoparticles in the vitrimer matrix strengthens the material leading to the increase of the elastic modulus by 44% and the tensile stress by 25%. Simultaneously, nanoparticles enhance the dimensional stability of the material since they reduce the coefficient of thermal expansion. At the same time, the transesterification catalyst provides the thermoset with the welding ability at heating, when the chain exchange reactions are accelerated. For the first time, it was shown that the silica nanoparticles strengthen welding joints in vitrimers, which is extremely important, since it allows to repeatedly use products made of thermosets and heal defects in them. Such materials hold great promise for use in durable protective coatings, adhesives, sealants and many other applications.
通过在固化剂4-甲基六氢邻苯二甲酸酐（MHHPA）、酯交换催化剂乙酰丙酮锌（ZAA）和10-15纳米球形二氧化硅纳米颗粒存在的情况下对双酚A二缩水甘油醚（DGEBA）进行热固化，制备了具有可调基质的环氧/二氧化硅热固性材料（可塑弹性体）。通过拉伸试验、热机械分析和动态力学分析研究了所得材料的性能。结果表明，在室温下，在可塑弹性体基质中引入5-10重量%的二氧化硅纳米颗粒可增强材料，使弹性模量提高44%，拉伸应力提高25%。同时，纳米颗粒提高了材料的尺寸稳定性，因为它们降低了热膨胀系数。同时，酯交换催化剂使热固性材料在加热时具有焊接能力，此时链交换反应加速。首次表明，二氧化硅纳米颗粒增强了可塑弹性体中的焊接接头，这极其重要，因为它允许重复使用由热固性材料制成的产品并修复其中的缺陷。此类材料在耐用防护涂层、粘合剂、密封剂及许多其他应用中具有广阔的应用前景。
