This study presents the preparation of polypropylene composites filled with mixtures of household waste of mate-tea and eucalypt particles and aims to increase the economic value chain of mate-tea. Filler mix- tures in proportions ranging from 0% to 60% with a fixed PP matrix at 40% were prepared in order to eval- uate only the effect of the filler on thermochemical, physical and mechanical properties and on the morphology. The main findings showed that the addition of filler from natural sources decreased thermal stability of composites, but that the temperature of crystallisation increased. Composites with a higher proportion of wood particles showed higher hydrophobic character; however, only the composites with 60% and 54% of mate-tea waste particles showed significantly higher results for water absorption. The use of eucalypt particles increased more mechanical properties than that of household waste, which proves its efficiency as filler. Nevertheless, the use of household waste also increased the properties of the final product and showed that it can be a good alternative for the use of renewable materials in the production of polymeric composites.201
The effect of thermal treatments on physical and mechanical properties of rose gum and Sydney blue gum wood was evaluated. Wood samples were thermally modified in a combination: pre-treatment in an autoclave (127°C - 1h) and treatment in an oven (180-240°C - 4h); and only treatment in an oven at 180-240°C for 4h. Chemical changes in the structure of woods were evaluated through infrared spectroscopy. Evaluation of physical properties was performed through mass loss, specific gravity, equilibrium moisture content and dimensional stability tests. Surface changes were analyzed through apparent contact angle technique and static bending tests were carried out to evaluate the mechanical behavior. Use of pre-treatment in autoclave affected the properties analyzed, however oven, resulted in the highest changes on wood from both species. Chemical changes were related to the degradation of hemicelluloses. Moreover, a significant decrease of hygroscopicity and mechanical strength of thermally modified woods was observed, while specific gravity did not significantly change for either of the species studied. The best results of decrease of wettability were found in low temperatures, while dimensional stability increased as a function of temperature of exposure in oven. The highest loss of mechanical strength was observed at 240°C for both species.