Obtenção e caracterização de compósito em matriz polimérica de ABS utilizando argila refratária para a retardância de chama

Abstract

The development of composites revolutionized the world with regard to materials science and engineering, seeking new products that are more cost-effective and care more for the environment. Polymers have a great limitation regarding their flammability property and a potential alternative to improve this characteristic is the inclusion of ceramic material in a polymer matrix. Refractory clay is an abundant ceramic material. It has a low cost and withstands very high temperatures (above 1300ºC), in addition to being often discarded from the manufacturing process and stored in open warehouses as it does not have enough plasticity for easy conformation. Thus, the objective of this project is to obtain and characterize a composite produced in an ABS (Acrylonitrile butadiene styrene) polymer matrix using refractory clay (AR) as reinforcement, in order to optimize flame retardancy. Composites were produced by melt compounding in an internal mixer varying the mass content of RC in 0, 2.5, 5, 7.5, 10, 15 and 20 wt% regarding the mass of ABS/AR. Neat ABS was also processed under the same conditions in order to act as reference. The composites that presented better mechanical performance (determined by statistical analysis ANOVA) were selected so, in a second set of experiments they were processed by extrusion and injection molding. The composites were produced with RC mass ratio of 0, 10, 15 and 20% in the mass of ABS/AR. Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Thermal Deflection Temperature (HDT), Fourier Transform Infrared Spectroscopy (FTIR), tensile, flexural and Izod impact tests were performed to characterize the polymer itself and the composites. Thermal and mechanical analysis showed that the addition of RC in the polymer matrix did not have a negative influence on the composites produced, that had a glass transition temperature of approximately 109ºC, elastic and flexural modulus of up to 3.52 GPa and 72.96 GPa, respectively. There was a good reduction in the ABS flammability (according to UL 94 tests), considering that the ABS/AR composite with 20wt% had faster self-extinguish properties and the other composites had a reduction in burning speed when compared to the reference material (neat ABS), obtaining a burning rate of 33.4 mm/min for the sample with the highest RC content. The use of RC in this research brought an innovation, with superior results from those found in the literature, considering that a greater incorporation of clay was possible, maintaining good mechanical properties, thermal stability and low flammability for the composites produced.