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- Mechanical caracterisation of polyester resin and corn natural fibers compositePublication . Queijo, Luis; Rocha, JoãoThe use of natural fibers as reinforcement in polymer matrix composites is gaining popularity in the development of renewable products. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. The work deals with the characteristics of fiber composites that can offer several advantages, like low cost, weight savings and relatively good mechanical properties. It focuses on the effects of corn fibers as reinforcement agents in composites. Mechanical testing was performed to qualify the reinforcement properties of the corn fibers and consequently to compare with fiberglass composites.
- Mechanical caracterisation of polyester and sunflower natural fiber compositePublication . Rocha, João; Queijo, LuisThe use of natural fibers as reinforcement in polymer matrix composites is gaining popularity in the development of renewable products. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. This work deals with the characteristics of natural fiber composites that can offer several advantages, like low cost, weight savings and relatively good mechanical properties. It focuses on the effects of sunflower fibers as reinforcement agents in composites. Mechanical testing of Sunflower natural fibers composite was performed to qualify and quantify the reinforcement properties. At same time, Glass fiber composite sample tests have been produced and characterized and both results have been compared. From results comparison we can affirm that the produced polymeric sunflower fiber composite has adequate mechanical properties for lots of industrial applications even, as expected, these are lower than glass fiber composites. Using this natural fiber content this product become a more ecological substitute and environment friendly that the traditional polymeric glass fiber composites. For other way, once stems from sunflower plants are wastes that traditionally are left in the field, shredded and incorporated in to the soil, acting like natural low cost substrate, by collecting them and giving them some commercial value will make crops more profitable.
- The influence of manufacturing factors in the short-fiber non-woven chestnut hedgehog spine-reinforced polyester composite performancePublication . Ribeiro, J.E.; Rocha, João; Queijo, LuisOne of the most important agricultural products in the northeast of Portugal is sweet chestnuts. In this region only, several tons of this product are produced every year. Sweet chestnuts are enclosed in a hedgehog covered with a large number of short and fine spines and containing more than one nut. This hedgehog, with long spines, does not have any commercial value, and they are considered an agricultural waste that is left in the fields to be incorporated into the soil. In this work, the authors propose to study the influence of some factors in the short-fiber non-woven chestnut hedgehog spine-reinforced polyester composite performance. For this purpose, the tensile properties of chestnut spines were determined by implementing a design of experiments (DOE) approach developed by Taguchi. Thus, the factors that will be controlled are the fiber dispersion which is defined by fiber/matrix mass ratio or weight fraction, the interfacial strength that could be improved using an alkali–silane treatment and, finally, the moisture level in the fibers. For each factor, three levels were used, an L9 orthogonal array of experiments was implemented to evaluate tensile and flexural properties. These properties were determined based on results of 54 tests, and the maximum mean values for tensile and flexural strength were 23.5 MPa and 33.6 MPa, respectively. The most influential factor for maximizing the tensile strength was the volume fraction of fiber with a contribution of 30%, and most influential factor for maximizing the flexural strength was the moisture level with a contribution of 65%. The determined mean value of tensile strength of the spines was 148 MPa.
- Mechanical caracterisation of polyester and sunflower natural fiber compositePublication . Rocha, João; Queijo, LuisThe use of natural fibers as reinforcement in polymer matrix composites is gaining popularity in the development of renewable products. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. This work deals with the characteristics of natural fiber composites that can offer several advantages, like low cost, weight savings and relatively good mechanical properties. It focuses on the effects of sunflower fibers as reinforcement agents in composites. Mechanical testing of Sunflower natural fibers composite was performed to qualify and quantify the reinforcement properties. At same time, Glass fiber composite sample tests have been produced and characterized and both results have been compared. From results comparison we can affirm that the produced polymeric sunflower fiber composite has adequate mechanical properties for lots of industrial applications even, as expected, these are lower than glass fiber composites. Using this natural fiber content this product become a more ecological substitute and environment friendly that the traditional polymeric glass fiber composites. For other way, once stems from sunflower plants are wastes that traditionally are left in the field, shredded and incorporated in to the soil, acting like natural low cost substrate, by collecting them and giving them some commercial value will make crops more profitable.