THE DEVELOPMENT AND EXPLOITATION OF ACCELERATED DURABILITY TESTS - THE NEW ASTM D429 METHOD G IMMERSION TEST AND POTENTIAL FUTURE DEVELOPMENTS

摘要

Typical tests of adhesive bond strength are quasi-static (e.g., ASTM D429 Methods A-F) and are used to check primary adhesion. A recently completed elastomer bonding consortium project investigated the factors that contribute significantly to (static) rubber-to-metal bond failure. The project evolved through three phases and attracted international support from various industrial sectors. The main project outcome was a novel accelerated durability test, now adopted as ASTM D429 Method G. This test method achieves rapid bond failure under mild conditions and will be described in detail. Many elastomer/adhesive/substrate combinations, including water-based systems, have been investigated to date and a selection of the data will be presented. The new methodology can be employed to evaluate the influence of rubber compounding, adhesive type, surface preparation, etc, on bond durability. There remains a need for a test method that is capable of effectively evaluating elastomer bonds under dynamic (cyclic fatigue) loading. Such a test will be developed as part of a new MERL consortium project and applied to assess various processing factors (state of cure, cure profile etc), ageing and environmental effects on elastomer bond performance. Once developed, dynamic test results will be compared with those from the static ASTM D429 Method G. The dynamic test methodology may prove suitable for eventual adoption as an international standard.