Crusher/grinder Fiber comminution during polymer compounding/extrusion for renewable, recyclable biocomposites 11/2/15 Solids processing: crusher

PLA/flax fiber biocomposites Poly(lactic acid) (PLA) is a recyclable thermoplastic polymer, which can be generated from renewable resources Flax fibers have high elastic moduli and specific tensile strengths During melt compounding of flax fibers with PLA, the fiber morphology changes This example problem models the fiber dimensions distributions before and after compounding to establish a ‘grinding’ model for predicting after-compounding fiber properties Note – fiber aspect ratio is critical to determining its reinforcing effects in composites. Length to diameter ratios (L/D ratios) of 100 or more can give dispersed fiber composites with tensile strengths approach those of continuous fiber composites

Polymer composite fillers LHS = pultruded continuous fiber beam; Center = cross-ply laminate of layered continuous fiber tapes; RHS – top = random chopped fiber composite; bottom = particulate composite

Chopped fiber orientation a) long, aligned, high density; b) short, aligned; c) random

Extrusion compounding: chopped fiber composites F. J. Thakur, Green composites from natural resources, CRC Press, 2014, Chapter 4. Hemp and hemp-fiber composites.

Fiber morphology data