Poly(ε-caprolactone) (PCL) is a biodegradable and biocompatible commercially produced thermoplastic with unique properties similar to low-density poly(ethylene) (LDPE) such as high elongation at break, and facile melt-processing. However, despite vast progress in producing PCL based materials, PCL suffers from low tensile strength (16-27 MPa), Young’s Modulus (250-420 MPa) and higher cost compared to LDPE and Polypropylene (PP). To produce a high strength composite while maintain biodegradability, PCL has been melt blended with Cellulose Nanocrystals (CNC) and Cellulose Nanofibres (CNF). Melt blending of cellulose in a traditional fashion is not only energy and time consuming, it also results in cellulose agglomeration due to polysaccharide aggregation and large interfacial energy, and therefore poor dispersion leading to inferior mechanical properties. The “wet-feeding” strategy is already an industrial compounding reality for clay-based composites and recently it has been reported also for CNC/poly(lactid acid) nanocomposites that not only prevents polysaccharide aggregation but also in which the drying takes place during the extrusion. This method may also lead to a three-dimensional percolating cellulose network in the composite after melt processing.<br/>This work reports the development of a wet feeding method to prepare biodegradable cellulosic fibers/PCL composites. A cellulosic pulp was selected for this study. The concentration of cellulosic fibers in the composites was varied from 0-20% and the resulting thermal-mechanical properties of the composites were investigated by DSC, TGA, Tensile testing and DMA. The effect of the wet feeding on the composite morphology was assessed by SEM and microtomography. The effect of the shear stress on the shortening and dispersion of the cellulose fibers is reported. With the addition of 20% cellulosic fibers, the Young’s Modulus was increased from 240 MPa to 1500 MPa for the composite produced by using the wet feeding strategy, while for the dry feeding one the value was 710 MPa. The morphological analysis confirms a better dispersion of the fibers in the polymeric matrix for the composites prepared by using the wet feeding extrusion strategy in comparison to the dry feeding one.

Melt-processing of cellulose pulp and polycaprolactone composites: Wet feeding approach to improve the filler dispersion

253rd National Meeting (2017)

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