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DURABILITY OF CONTINUOUS FIBRE REINFORCED THERMO-PLASTIC COMPOSITES WITH EMPHASIS ON THE INTERFACE BEHAVIOUR AND THE METHOD OF FABRICATION.

Objective

The objective of this project is the characterisation and modelling of the quality of the impregnation of the glass fibres by thermoplastics (polyethyleneterephthalate, polyamide-6,6 and polyetherimide) and the durability of the resulting thermoplastic composites.
The objective of this project is the characterisation and modelling of the quality of the impregnation of glass fibres by thermoplastics (polyethyleneterephthalate, polyamide-6,6 and polyetherimide) and the durability of the resulting thermoplastic composites. Long cycle times and excess energy requirements are characteristics of the current fabrication process of the products out of semimanufacture tape. This research focusses on the improvement of the impregnation quality of the powder impregnation of bundles of fibres and development of a short cycle stamping process with dielectric heating. In this respect carbon black is added to polyetherimide to make this thermoplastic suitable for dielectric heating. The durability of the final product is investigated by hydrothermal ageing, environmental stress corrosion, fatigue, thermal cycling and creep.

The impregnation of prepregs has been improved and a new dielectric heating process has been developed successfully for polyethyleneterephthalate (PET) and polyetherimide (PEI) composites. The process has good potential for polyamide-6,6 (PA66) composites, but needs further investigation. From the durability results it appeared that the consolidation phase after the heating step needs more consideration in future work.

A lot of data has been produced on the durability of the various materials under different environmental and mechanical loads. They will be useful in assessing the behaviour of the different materials in practical use.

PA66 and PEI composites appear to be suitable materials for temperatures up to 60 C in humid environments. Only PEI composite can stand higher temperatures and more severe environments such as acidic solutions.

PET composite is not suitable as a construction materials in practical applications where a humid or corrosive environment occurs.

The processing steps and the behaviour of the materials in different environments under different mechanical loadings such as creep and fatigue have been modelled. Software has been developed, which makes it possible to integrate design tools. This leads to predictions of environmental behaviour and durability as a function of the manufacturing route.
With composites on the basis of thermoplastic matrices in comparison with thermoset matrices it is possible to get a better dimensioning of structures. Thermoplastic composites are expected to have an improved damage tolerance. Replacing thermosets by thermoplastics as matrix increases the delamination energy and the residual properties after impact. This can further be improved by using longer fibres.

Long cycle times and excess energy requirements are characteristics of the current fabrication process of the products out of semi-manufacturing tape. This research focuses on the improvement of the impregnation quality of the powder impregnation of bundles of fibres and development of a short cycle stamping process with dielectric heating. In this respect carbon black is added to polyetherimide to make this thermoplastic suitable for dielectric heating.

The durability of the final product will be investigated by: hydrothermal ageing, environmental stress corrosion, fatigue, thermal cycling and creep.

Samples produced by different processing routes and after different loading histories will be investigated using simple mechanical tests, fracture surface analyses using SEM, DMTA, DSC, Raman- and FTIR-spectroscopy and microhadness.

Coordinator

N.V KEMA
Address
P.o. Box 9035
6800 ET Arnhem
Netherlands

Participants (5)

Integrated Aerospace Sciences Corporation
Greece
Address
Miaouli Street 22
18345 Moschato
SNPE
France
Universidad de Valladolid
Spain
Address
Plaza De Santa Cruz
47005 Valladolid
University of Paisley
United Kingdom
Address
High Street
PA1 2BE Paisley
École Nationale Supérieure des Mines de Paris
France
Address
60 Boulevard Saint-michel
75272 Paris