On the role of free carboxylic groups and cluster conformation on the surface scratch healing behaviour of ionomers

While ionomers are well known for their healing ability under ballistic impact conditions, the present work focusses on elucidating the effect of both the free carboxylic content and the cluster state on well-controlled isothermal low temperature healing of surface scratches in ionomer blends. It is shown that under the conditions explored the healing efficiency depends primarily on the amount of free carboxylic groups and the presence of clusters plays a secondary role. A free carboxylic end group concentration of about 3 mol% is required to obtain optimal healing.