Hybridisation of man-made cellulose and glass reinforcement in short-fibre composites for injection moulding - Effects on mechanical performance

This experimental research aims to determine the influence of reinforcement hybridisation onto basic mechanical properties of misaligned short-fibre composites. For this purpose different short-fibre hybrid polypropylene composites with E-glass and cellulose reinforcements, which are characterised by different stress-strain characteristics were compounded and injection moulded. The volumetric fractions of reinforcement and compatibiliser contents were maintained at the proportional volumetric levels to enable correlation of filling ratios and reinforcement geometry with mechanical performance of the manufactured hybrids. This research helps to foresee mechanical performance of the newly developed hybrids and gives clues to effective hybridisation by showing the basic dependencies. It was found that especially flexural strength can be boosted by the addition of a second filler to short-fibres owing to its better response to compressive stresses during 3-point bending of the bar, as long as its Young's modulus is in the range or higher than that of fibres, has similar stress-strain characteristics and its good bonding with matrix is provided. The hybridisation of short-fibres with microfillers also reduces void content and fibre damage upon processing.