ABSTRACT

Adhesive properties are often affected by water. In this study, to clarify the water-resistant properties of a thermosetting epoxy adhesive containing dicyandiamide (DICY) and carboxyl-terminated butadiene acrylonitrile rubber (CTBN), immersion tests of open-faced specimens and bulk specimens in water were performed, and the changes in the properties were investigated in terms of chemistry and mechanical strength. After immersing the open-faced specimens in water, the mechanical strengths were evaluated by two different methods: interfacial cutting method and secondary bonding method. Using both methods, a decrease in strength with immersion time was obtained, and the tendencies of the strength change were found to be very similar for the different evaluation methods. Chemical changes were also evaluated by infrared spectroscopy. Through periodical measurements of the infrared spectra of a fully-cured bulk adhesive specimen during water immersion, the chemical degradation of the epoxy adhesive containing DICY and CTBN was investigated, revealing an association with the change in mechanical strength in which hydrolysis of the cyano groups in DICY and CTBN led to a decrease in strength. Strength recovery experiments were also conducted by drying the specimens after water immersion, determining that the mechanical recovery strength changed with water temperature and immersion time.

摘要

粘合性能通常受水影响。本研究为阐明含双氰胺 (DICY) 和端羧基丁二烯丙烯腈橡胶 (CTBN) 的热固性环氧胶粘剂的耐水性能，进行了开面试件和大块试件在水中的浸渍试验，并分析了其变化在化学和机械强度方面对性能进行了研究。将开面试样浸入水中后，通过两种不同的方法评估机械强度：界面切割法和二次粘合法。使用这两种方法，强度随浸泡时间的降低而降低，并且发现不同评估方法的强度变化趋势非常相似。还通过红外光谱评估了化学变化。通过在水浸过程中对完全固化的本体粘合剂样品的红外光谱进行定期测量，研究了含有 DICY 和 CTBN 的环氧粘合剂的化学降解，揭示了与机械强度变化的关联，其中氰基水解DICY 和 CTBN 导致强度下降。还通过在水浸后干燥试样进行强度恢复实验，确定机械恢复强度随水温和浸水时间而变化。揭示了与机械强度变化的关联，其中 DICY 和 CTBN 中氰基的水解导致强度降低。还通过在水浸后干燥试样进行强度恢复实验，确定机械恢复强度随水温和浸水时间而变化。揭示了与机械强度变化的关联，其中 DICY 和 CTBN 中氰基的水解导致强度降低。还通过在水浸后干燥试样进行强度恢复实验，确定机械恢复强度随水温和浸水时间而变化。