Natural weathering of composites developed from cellulose waste and post-consumer paper

Abstract

The development of materials that are highly degradable at the end of their life cycle helps reduce the volume of solid waste disposed of in landfills. This study aimed to produce composites from cellulose and paper residues as reinforcing fibers and from thermoplastic starch (TPS) as a matrix to analyze the effect of exposure to natural weathering in the environments of two Universities, one in Brazil (Universidade Feevale) and the other in Finland (HAMK). During the test period, the season in Brazil was summer, with high temperatures and solar radiation; in Finland, the season was winter, with negative temperatures, high air humidity, and snowfall. The materials were prepared using the tape-casting method and characterized by Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA), having been subjected to the weather for 0, 28, and 42 days at Universidade Feevale and HAMK. At the end of each period, they were characterized by Scanning Electron Microscopy (SEM) and photographs. The results showed that the thermal stability of the composites was better compared to TPS and cellulose, and superior mechanical properties were shown in the cellulose-based composite. Thus, heterogeneous mixtures emerged from the addition of fibers to the polymer matrix. After the environmental exposure, the visualization of the micrographs and photographs indicated that the samples exposed in the two environments were brittle, shrunken, yellowed, and cracked. It was also verified that the samples exposed at Universidade Feevale suffered greater environmental degradation, and the incorporation of fibers in the composites delayed this effect at the two study sites.