A study of transcrystallinity and its effect on the interface in flax fibre reinforced composite materials

Cellulose fibres have long been used in the plastics industry as cost-cutti ng materials. Nowadays they are recognised as a potential replacement for g lass fibres for use as reinforcing agents in composite materials. They have a number of certain advantages over glass fibres, such as low cost, high s trength-to-weight ratio, biodegradability and ease of processing. In this s tudy crystallisation from the melt of two different isotactic polypropylene matrices (iPP) in the presence of flax (Linum usitatissinum) fibres of fou r different types (green flax, dew retted flax. Duralin(R) treated flax and stearic acid sized flax) was examined. The effect of processing parameters such as crystallisation temperature and cooling rate was investigated usin g hot stage optical microscopy. Differential scanning calorimetry (DSC) was used to investigate the inner morphology of the transcrystalline (TC) laye r. Scanning electron microscopy (SEM) and X-ray diffraction were used in an attempt to identify the origin of the TC layer in connection with the stru ctural characteristics of the fibres. The effect of transcrystallinity upon the mechanical properties of the interface was assessed using the single f ibre fragmentation test. It was found that the interfacial adhesion is impr oved by the presence of a TC layer. (C) 2001 Elsevier Science Ltd. All righ ts reserved.