Preparation and Properties of Green Composites Based on Tapioca Starch and Differently Recycled Paper Cellulose Fibers

Green composites obtained from biodegradable renewable resources have gained much attention due to environmental problems resulting from conventionally synthetic plastics and a global increasing demand for alternatives to fossil resources. In this work we used different cellulose fibers from used office paper and newspaper as reinforcement for thermoplastic starch (TPS) in order to improve their poor mechanical, thermal and water resistance properties. These composites were prepared by using tapioca starch plasticized by glycerol (30 % wt/wt of glycerol to starch) as matrix reinforced by the extracted cellulose fibers with the contents ranging from 0 to 8 % (wt/wt of fibers to matrix). Properties of composites were determined by mechanical tensile tests, differential scanning calorimetry, thermogravimetric analysis, water absorption measurements, scanning electron microscopy, and soil burial tests. The results showed that the introduction of either office paper or newspaper cellulose fibers caused the improvement of tensile strength and elastic modulus, thermal stability, and water resistance for composites when compared to the non-reinforced TPS. Scanning electron microscopy showed a good adhesion between matrix and fibers. Moreover, the composites biological degraded completely after 8 weeks but required a longer time compared to the non-reinforced TPS. The results indicated that these green composites could be utilized as commodity plastics being strong, inexpensive, plentiful and recyclable.