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| Author(s): |
Barbara Iria Silva Mano
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Química |
| Defense date: | 2009-12-16 |
| Examining board members: |
Marco Aurelio De Paoli;
Laura Hecker de Carvalho;
Ines Joekes
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| Advisor: | Marco Aurelio De Paoli |
| Abstract | |
The development of materials formulated with vegetal fibers is interesting for countries with high availability of natural resources, like Brazil, due to the possibility of promoting technological development using their own raw materials. The use of short vegetal fibers composites with polymeric matrices have been receiving attention due to the fact that the fibers increase the mechanical properties of the polymers and have potential to substitute inorganic fibers, in special glass fiber, with many advantages that include being lighter, biodegradable and less abrasive to the processing equipments. In this work, the incorporation of curauá fibers on polypropylene matrix by extrusion and injection molding was studied, testing different screw rotation speed in the twin-screw extruder, the fiber and the coupling agent content. The composites prepared with the rotation of 300 rpm, 20 wt% of fiber and 2 wt% of coupling agent showed the best mechanical properties evaluated in tensile, flexural and impact tests This mechanical performance does not overcome the properties of the composites reinforced with glass fibers, but are competitive with them. The degradation and stabilization were evaluated through natural ageing of samples of PP and composites with and without commercial stabilizers, in order to analyze the effect of each component on the degradation of the system. While the coupling agent worked prodegrading the systems, the fibers had a screening effect and protected them from the ageing. This part of the work was important to choose suitable additivation for the composites. The stabilizers chosen for the formulation worked satisfactorily in preventing the ageing of the samples and reduced the prodegrading effect of the coupling agent. Based on these results, it is possible to define a suitable formulation of the composites for each final application. (AU) | |