Paper to 16th Annual Meeting of the Polymer Processing Society, Shanghai, China, 18th-23rd June 2000

S F Bush with O K Ademosu, S A Harrison, J M Methven and S Smith

Introduction

The generally poor fire resistance of hydrocarbon polymers has greatly inhibited their application in places where human beings are expected to congregate in confined spaces. Underground transportation systems, leisure centres, and apartment blocks are all examples where the flammability of polymers has been implicated in substantial loss of life in different parts of the world.

Public concern is also focussed on the recycling and reuse of polymers issue. Arguably, used tyres constitute the single largest, most predictable and most intractable recycling problem in the mass car-owning parts of the world. This is because of the numbers involved (around one tyre per adult per year in the industrialised world) and the fact that as a thermoset, rubber cannot be reprocessed by melting into a new tyre or some other object.

The present paper introduces a new technology which aims to provide potential large scale applications of rubber from used tyres and to provide sufficient fire resistance to allow use in public areas. Besides the various mixing sequences involved, the technology encompasses in some of its forms the chemical grafting of the rubber on to other hydrocarbon matrices and the use of different fire retardants. This laboratory’s long-fibre reinforcement technology is also used to provide another degree of freedom in meeting both technical and economic goals^[1].

Fire resistance is typically characterised by the Limiting Oxygen Index (LOI) test^[2] and mechanical properties are characterised by tensile strength and stiffness.

References

[1] S F Bush, Long glass fibre Reinforcement of Thermoplastics”, International Polymer Processing 14 (3) 1999, 282-290

[2] Determination of flammability by Oxygen Index BS 2782 Part 1: Method 141: 1986m ISO 45891 – 1984