Mechanical properties of self-reinforced poly(lactic acid) composites prepared by compression moulding of non-woven precursors

A hot compaction method has been used to form all-PLA composites by partial melting and fusion of fibres in non-woven mats where the matrix phase is formed from partially melted fibres and the reinforcement phase is the original PLA fibres that remain. Compaction required a minimum of 10 min heating at temperature range 172C to 176C under a load of 2.4 MPa. An advantage is that the oriented high tensile strength fibre properties are retained, while matrix adhesion is strong because melt adhesion is provided by the same polymer. The all-PLA composite structure was confirmed using scanning electron microscopy (SEM) and wide-angle X-ray scattering. Mechanical properties were evaluated from modulated force thermo-mechanical analysis. The temperature window below melting temperature of PLA of about at 172C to 176C was found as the optimum temperature for all-PLA composites with optimum properties. SEM study also shown the gaps between the fibers are filled with recrystallised material that has melted from the original fibres