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Title: The strength and failure behaviour of short glass fibre reinforced polyamide 6
Author: Collins, J. F.
ISNI:       0000 0001 3560 6297
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1981
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The strength and failure behaviour of nylon 6 reinforced with short E-glass fibres has been studied. The fibres were treated with different sizing compounds in order to modify the interface between the glass and polymer. The principal objective of the work was to assess, by means of mechanical testing and microscopy, the role of the interfacial bond in controlling the properties of these materials. It has been shown that the mechanical behaviour of glass reinforced nylon 6 is controlled mainly by the fibre concentration, length, and orientation and that stiffness enhancement can be adequately predicted by a modified rule of mixtures expression. The behaviour is also strongly influenced by the type of sizing compound employed on the fibres. The results clearly demonstrate the beneficial effects of silane coupling agents. In the 'dry' condition some composites exhibited a 30% strength reduction on omission of the silane, but in others this caused little variation. In the wet state however, silane treatments produced far superior properties in all cases. In addition, the size apparently exerts considerable control over the properties, indirectly, by effecting the fibre dispersion and breakage during compounding and moulding. The failure mechanism as assessed by optical and scanning electron microscopy and by acoustic emission analysis, was shown to be of a dual nature. Failure was initiated by fibre-matrix debonding in the core region of the mouldings, the debonded areas interlinked and became visible on a macroscopic scale as strain bands across the samples. The strain banding phenomenon in turn initiated a catastrophic brittle failure sequence, the resulting fracture surfaces exhibiting the characteristics of both weak and strongly bonded systems.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Materials, general