Tuesday, April 30, 2013
Exhibit Hall
The use of lignocellulosic fibers and their constituents, as raw materials in the production of polymeric and composite materials represents an exceptional opportunity of sustainable technological development. Natural fibers have proven to be suitable reinforcement materials for composites thanks to a combination of good mechanical properties and environmental advantages such as renewability and biodegradability. However, the hydrophilic character of natural fibers leads to low compatibility with hydrophobic polymer matrices. For this purpose, the aim of this work was to investigate the thermal properties of polypropylene composites reinforced with bleached cellulose obtained from sugarcane straw. For this, sugarcane straw was pretreated by diluted acid, delignified, treated with xylanase and bleached. All lignocellulosics materials were chemically characterized to evaluate the extent of pre-treatment, delignification, enzymatic, alkaline extraction and chemical bleaching. The final material was mixed with polypropylene, in a thermokinetic mixer for the composites preparation. Thermogravimetric analyses (TGA) was performed in order to evaluate the thermal properties of the obtained materials. Results revealed that the route chosen for obtaining cellulose was promising, but changes in the process must be carried in order to avoid losing large amounts of cellulose. At the final of the process of obtainment of bleached cellulose, the material had a great portion of cellulose and small portions of hemicelluloses and lignin. The TGA analyses are still in development. [Acknowledgements due to FAPESP, CNPq and CAPES]