Obtenção de compósitos de matriz polimérica reforçados com vermiculita e fibra de coco para absorção de ruídos

Abstract

Noise has been a very present component in large urban centers today. Faced with this problem, with the aim of controlling the level of noise generated by equipment, vehicles and people, several fibrous and porous materials have been developed, with the capacity to absorb and reduce noise at the source and receiver. The objective of this work is the synthesis and characterization of composites with a polymeric matrix of polyurethane resin (PU) with the addition of different proportions of expanded vermiculite ceramic and coconut fiber particles, in order to evaluate the attenuation of acoustic power in household appliances. Three different compositions were obtained, varying in weight: composite 1 (vermiculite 5%, coconut fiber 3%), composite 2 (vermiculite 10%, coconut fiber 5%) and composite 3 (vermiculite 13%, coconut fiber 7%). These composites were characterized by differential scanning calorimetry, scanning electron microscopy, X-ray diffractograms, Fourier transform infrared spectroscopy and acoustic impedance testing. The presence of disordered and porous structures resulting from the addition of vermiculite and coconut fiber attenuated the propagation of noise resulting from the absorption of sound wave energy by the materials. This attenuation was evidenced through an acoustic impedance test, where the highest absorption coefficient values were obtained for the two composites with the highest percentages of vermiculite and coconut fiber, in the studied frequency range of 80 to 6300 Hz. The results obtained demonstrated that the increase in vermiculite and coconut fiber content improved the thermal stability and sound absorption capacity of the composites due to the formation of pores with greater air retention.