Abstract
The influence of m-isopropenyl-±,±dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) and wood flour (WF) on the non-isothermal crystallisation behaviour of wood flour/polypropylene (WF/PP) composites was studied by differential scanning calorimetry. The crystalline morphology of PP was observed by polarised optical microscopy. The results demonstrated that the wood flour induces nucleation, while m-TMI-g-PP could greatly reduce the number of nucleation sites of the WF.
Avrami analysis showed that the non-isothermal crystallisation of PP and its composites followed the Avrami equation. The activation energy was calculated by using the Kissinger method, and the values were 253.3, 197.4 and 203.1kJ·mol-1 for PP, WF/PP and WF/m-TMI-g-PP/PP, respectively. This proved the nucleation effect of WF; the effect was much smaller in the presence of compatibiliser. The results indicate that the presence of m-TMI-g-PP generates a compatibilisation phenomenon, which leads to a reduction in the crystallisation rate, crystallisation temperature and crystallinity, and an increase in activation energy of PP compared with WF/PP composite.