Enhanced Cellulose Fiber for Polymer Composites

Abstract

In recent years, interest in renewable, environmentally friendly and low-cost materials has grown and has become a global trend. In view of the high consumption of petrochemical plastics that use reinforcing agents such as talc, calcium carbonates, and synthetic fibers to improve their performance, there is an opportunity for cellulose fibers to replace these materials. Cellulose fibers mainly meet this need, as they have very good mechanical properties, low density, high specific resistance, non-abrasive, renewable, ecological and biodegradability characteristics. Cellulose fiber is produced mainly for the paper and packaging industry. However, cellulose fiber available in regular processes is not suitable for polymer composites because it is highly aggregated. Most studies in literature about cellulose dewatering (filtration) are based on batch processes. To the best of our knowledge, there are no studies in the literature about continuous dewatering (filtration) of cellulose with additives suitable for polymer composites. For this reason, this work studied the variables in a continuous filtration process (rotating drum) that affect the dehydration (filtration rate) of the mixture of cellulose and additives for polymer composites applications. It also correlated the process variables and formulation with the dispersion of cellulose fibers in the polymer matrix and the performance of the polymer composites. The results showed that vacuum pressure and consistency were the parameters with higher influence in the quality of the cake. The addition of PP fibers and surfactant reduced the aggregation of cellulose fibers allowing to produce injection moulded samples without the need of pre-extrusion. The composites produced via direct injection moulding (without pre-extrusion) showed similar results to the ones produced using the traditional method (extrusion followed by injection moulding) with substantial increase in stiffness and a small reduction in the impact strength.