Adesão interfacial dos resíduos calcinados da concha de molusco em compósitos de polipropileno/polietileno com anidrido maleico

Abstract

New trends in the modification of properties of plastic materials have been observed due to the growing concern with the environment and the constant search for the use of particulate loads. These have mechanical properties that can improve the properties of polymers when reinforced with mineral fillers. In this work, the mechanical, morphological, thermal, flow properties and ash content of Polypropylene (PP) composites with 8% by mass of calcined shellfish (CC) were evaluated. To the composites, 2, 6 and 8% by mass of PE modified with maleic anhydride (PEAM) were added. Physical mixtures of PP and composites were performed using a single screw extruder, to verify the effect of PEMA on their properties. The fluidity of the samples (PP/CC) was altered, being reduced with the increase of the PEAM content. The impact strength of the composites was lower than that of the PP matrix, with the composite with 2% PEAM showing the best result among the others. The flexural modulus of the composites were higher than that of the PP, with an increase of 18% for the composite with 2% of PEAM, while the other mechanical properties of the composites were practically unchanged in relation to the matrix. From the thermogravimetric analysis, it was observed that the composite with the shell only calcined (PP/CC) was the one with the lowest residue content and the initial degradation temperature was lower than that of the PP, around 28%. The composite with 2% of PEAM showed the best thermal behavior among the other composites. Modification with PEAM resulted in composites with higher levels of inorganic residues and better properties than the composite with the shell only calcined. The content of CC particles present in the composites was determined by the ash content test, the dispersion, distribution and interfacial adhesion of the particles with the PP matrix were evaluated by scanning electron microscopy (SEM). When comparing the ash content of the samples obtained in this work, the composites with PEMA showed higher contents, especially the one with 6% PEMA. The morphology analysis showed that the particles were well dispersed and better adhered, particularly in the matrix with 10% of PEAM. It can be seen that the PEAM content improved the interfacial adhesion between the matrix and the inorganic reinforcement, the dispersion, and the distribution of CC in the polymer matrix, explaining its importance as a compatibilizing agent. Mathematical models of Pukanszky and Nicolais-Narkis were used to demonstrate the degree of adhesion of the matrix with the load, confirming the results obtained by the tests.