Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

High modulus polyethylene and glass fibre composites

The primary objective is to investigate lightweight resin composites with high energy absorption and good damage tolerance properties. The composites will comprise high modulus polyethylene (HMPE) fibres with other available fibres incorporated in resin matrices. This includes the development of a continuous fibre plasma etching process to improve the fibre to resin adhesion, the development of a fibre crosslinking process to improve the fibre creep performance, the formulation and characterisation of organic matrices such as fast curing polyester resin, and evaluating HMPE fibre and HMPE cross ply fibre composite mechanical properties.
A continuous plasma treatment process operating at a yarn speed of 1 ms{-1} and a yarn throughput of 0.7 kg minute{-1} has been developed. Cross ply composites using plasma treated HMPE fibre and epoxy resin have been made using a prepeg process. Electron spin resonance measurements have been initiated to identify the radical reactions during and after gamma irradiation of HMPE fibre to assist the identification of a crosslinking route. The curing recipe for the new polyester resin has been optimised. The plasticity of the polyester resin has been assessed by the effects of temperature on compressive yield stress and work hardening rate. Equipment has been constructed and fibre pull out tests made on samples having a range of plasma treatment.

The main conclusions of the studies are as follows:
a continuous plasma treatment process can be used to modify HMPE fibre surface and improve the adhesion to resin;
a batch X-linking process using gamma rays can be used to improve HMPE fibre creep performance without any significant fibre strength loss;
increasing the adhesion between HMPE fibre and epoxy resin in a composite reduces the impact failure energy;
hybrid composites containing HMPE and glass fibres show a maximum specific impact energy absorption with a 15% to 30% glass fibre content;
a polyester resin suitable for use as the matrix of a HMPE composite has been developed;
the effects of plasma treatment on a wide range of melt spun and gel spun HMPE fibres are similar;
cross links produced by irradiating melt spun HMPE fibre in an acetylene atmosphere are predominantly interchain dienes;
cross linked melt spun HMPE annealing corresponds to radical decay.


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