TWI Industrial Member Report Summary 440/1992
By S M Tavakoli
The effect of welding on polymers is being evaluated in several research programmes at TWI. Assessment of degradation and durability of joints are important aspects of this work.
Polymers are prone to degradation when exposed to environments encountered during processing and service. Irreversible processes can occur leading to deterioration in useful properties. Acrylonitrile-butadiene-styrene (ABS) is one of the most commercially important engineering thermoplastics, but, while ABS terpolymers are being used in many applications involving severe ageing conditions, the effect of welding on the structure and ageing properties of ABS is not known. This work investigated hot plate welds in ABS material. Mechanical properties were determined by tensile testing before and after accelerated ageing in air at 100°C, 110°C and 120°C and following immersion in warm and boiling water. Changes in chemical and physical properties associated with welding and ageing were evaluated, using FTIR, DMTA and DSC.