Ageing in Processed Polymers, Programme, Summary and Abstracts Discussion Meeting. Held at Birmingham University on 5-7 May 1993
Abstract
The manufacture of almost any plastic article involves some form of quenching as occurs, for example, in extrusion or injection moulding. The primary intention is to extract the product form, say, a mould as quickly as possible in order to maximize productivity. This, unfortunately, cannot be equated with the structural stability of the work piece and so the properties of the formed component may subsequently change (ie age) as it slowly relaxes to a more stable state. Such a process is purely physical in origin and may be reversed on heating: it must be distinguished from the more familiar chemical effects which are generally irreversible and are associated with decreases in molar mass. 'Physical ageing' was not a serious problem when polymers were used only for low grade applications (although even here it contributed to the 'cheap and nasty' image that is still widespread for plastics-a simple example is the warping of an article that was well formed initially.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1993
- Accession Number
- ADA268931
Entities
Organizations
- Office of Naval Research