Reaproveitamento de resíduos da agroindústria da laranja para a produção de compostos biodegradáveis em matriz de PBS

Abstract

The employment of biodegradable polymers is a partial solution to the problem of environmental plastic pollution, since conventional polymers are resistant to many environmental influences and it may take centuries for them to disappear completely from nature. Despite the environmental benefits and technical properties suitable for many applications, biodegradable polymers are generally limited by their performance and cost, which are relatively less attractive than conventional polymers. The residual fiber (RF), which is a by-product of the orange juice industries, can be plasticized with glycerol, under high temperatures and shear strain, resulting in the thermoplastic fiber (TPF). The use of TPF can reduce the costs of biodegradable polymers, enhance their biodegradability, and add value to agro-industrial waste. Thus, injected poly(butylene succinate), or PBS, specimens were produced with TPF additions in up to 50% mass fraction. The impacts of TPF content in PBS were evaluated by mechanical (tensile testing), thermal (Differential Scanning Calorimetry and Thermogravimetric Analysis), rheological, morphological (Scanning Electron Microscopy) and molecular weight (Size Exclusion Chromatography) analyses, in addition to the simulation of weight loss by burial. Although TPF did not significantly modify the PBS molecular weight, the rheological experiments have shown a trend for the formation of a physical interaction network with TPF additions from 30% onwards. Despite evidences of adhesion between the pectin/lignocellulosic fiber and pectin/PBS phases, the mechanical properties of the compounds were reduced, which was suggested to be due to excess glycerol and/or TPF mechanical characteristics. The weight loss, the appearance of a population with lower molecular weight, and the formation of holes on the PBS/50TPF surface, compared to the PBS surface, substantiate that TPF has potential to enhance the biodegradability of plastic products.