Hybrid all-cellulose reinforcement in polypropylene matrix biocomposites for injection moulding - influence of particle geometry and volume fraction on hybrid effect

The presented study is focused on evaluation of influence of reinforcement volume fraction and geometry on the occurrence of positive hybrid effect by the hybridisation of man-made cellulose fibres (rayon viscose) with cellulose microparticle fillers applied in polypropylene matrix. Four volume fractions of reinforcement were used at 1:1 combination of short man-made cellulose fibres with cellulose microfillers of different aspect ratio. The highest volume fraction was applied for a comparison of four types of cellulose microfillers characterised by different aspect ratios. Proportional volume content of compatibiliser to volume of reinforcement and manufacturing conditions were maintained for all composites. Positive hybrid effect present in tensile and flexural performance was found to result from different factors such as: favourable combination of reinforcement owing to their similar stress-strain characteristic, decreased void fraction, slightly improved orientation of short rayon viscose fibres in hybrid and reduced relaxation of stresses during deformation.

Automated summary

This study evaluates the influence of reinforcement volume fraction and geometry on the positive hybrid effect of man-made cellulose fibres mixed with cellulose microfillers. The results show that the hybrid materials exhibit improved tensile and flexural performance due to the favorable combination of reinforcement, decreased void fraction, improved orientation of short fibres, and reduced stress relaxation during deformation.