Influência da mercerização em fibras de malva nas propriedades físico-mecânicas de compósito à base de polipropileno

Abstract

The search for improved materials that use natural resources derived from renewable sources and that aim to reuse industrial waste produced on a large scale, which do not have their own destination, has been growing and being the subject of several studies and research. In this sense, the present work aimed to evaluate the influence of chemical mercerization treatment on mallow fibers (Ureta Lobata L.) on the properties of composites using residues of bi-axially oriented polypropylene (BOPP) films as matrix. The fibers were mercerized using a 5% NaOH solution and characterized along with the in natura fibers in terms of their physical, structural, thermal, mechanical and morphological properties. Two types of composites were produced, one with in natura fibers and the other with mercerized fibers, through hot pressing, with a proportion of 70% of fibers. The physical, thermal, mechanical behavior and morphology of these composites were evaluated and compared. The in natura and mercerized fibers had a moisture content of 11.51% and 10.76%, respectively. The results of the XRD analysis indicated an increase in the crystallinity index from 65% to 71% with the mercerization of the fibers. The monofilament tensile test showed a significant increase in the tensile strength of the treated fibers. The composites are characterized as medium density fiberboard (MDF) as established by the standard. Both composites showed swelling and water absorption in accordance with the normative standard. The thermal conductivity and impact resistance of the composites were not influenced by the alkaline treatment. From the images of the composites obtained through the SEM, an improvement in the adhesion of the fiber with the matrix with the chemical treatment was observed.