The development of blends made from matrices of synthetic biodegradable polymers, and natural additives, are considered less environmentally aggressive materials. This work aimed to study the effects of gamma radiation on the properties of the thermoplastic starch (TPS)/poly(butylene adipateco-terephthalate) (PBAT). In this work, blends of TPS/PBAT were prepared with glycerol, castor oil and TWEEN ® 80, which were prepared by extrusion and then subjected to the radiation process and characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results demonstrated increased thermal degradation for the F2 (composed by OM) and F3 (composed by OM and TWEEN ® 80) regarding F0 (composed by glycerol) e F1 (composed by glycerol and TWEEN ® 80) blends. A good blend component chemical interaction and partial miscibility for the blends F0 and F1 was observed and compared to the others. However, F2 and F3 blends did not present co-continuous phases; being that the XRD curve patterns were not altered by the gamma radiation. The tests performed demonstrated that the irradiated and non-irradiated samples did not have their properties significantly altered. Thus, it was concluded that it is feasible to replace castor oil with glycerol in TPS/PBAT blends.

Resumo: O objetivo principal deste trabalho é avaliar o comportamento mecânico de laminados de tecidos de fibras de aramida (Kevlar) com diferentes matrizes poliméricas termorrígidas (poliéster insaturada e epóxi) produzidos por infusão a vácuo. A qualidade do processamento, isto é, a homogeneidade dos compósitos, foi verificada por ensaio não destrutivo (Ultrassom C-Scan) e suas propriedades mecânicas foram obtidas em ensaios de tração, flexão, compressão e short beam. O comportamento em tração do compósito com matriz epóxi e poliéster foi similar. Porém, as resistências à compressão, à flexão, e a short beam do compósito aramida/epóxi foram até três vezes superiores ao apresentado pelo compósito aramida/poliéster.

This study aimed to prepare blends of natural polymers of TPS with PBAT by reactive extrusion with irradiation process, using the plasticizers (castor oil and glycerol) to evaluate the thermal and chemical properties. The blends were submitted to the irradiation process using a Cobalt-60 source at a 25 kGy dose and then characterized by FTIR and DSC analysis. According to the results obtained in the FTIR tests, the blends did not undergo chemical changes during the irradiation process and, thus, maintained their properties. In the DSC tests, it was observed that the blends F2 (castor oil) and F3 (castor oil and TWEEN® 80) showed higher values of heat flow for degradation than the samples F0 (glycerol) and F1 (glycerol and TWEEN® 80), probably due to the chemical interaction of castor oil and its constituents. There was no thermal variation in the irradiation process between blends F0 and F1 or F2 and F3. It was concluded that it is feasible to replace castor oil with glycerol in TPS/PBAT blends, and the irradiation using a Cobalt-60 source, not changed the final properties analyzed.

The aim of this study was to analyze the changes in the structure and crystallinity of non-irradiated and irradiated thermoplastic starch blends (TPS)/poly (butylene adipate-co-terephthalate) -PBAT and also to evaluate the behavior of castor oil replacing glycerol. In this work, the characterization was performed by using X-ray diffraction (XRD), in which the crystallinity index (IC) of nonirradiated and irradiated blends of TPS/PBAT was calculated, through the software Bruker DIFFRAC.EVA® v4.22. For the plastification of the TPS, glycerol, castor oil and TWEEN® 80 were used to verify their compatibility and establish a comparison among the blends. The samples were prepared by extrusion and irradiated at 25 kGy with gamma rays with a 60Co source. However, the crystallinity indexes of the blends were altered according to the plasticizer used and the use of TWEEN® 80. Thus, it was concluded that replacing glycerol with castor oil is feasible in TPS/PBAT blends. RESUMOO objetivo deste estudo foi verificar as alterações na estrutura e cristalinidade de blendas de amido termoplástico (TPS)/poli (butileno adipato-co-tereftalato) -PBAT não irradiadas e irradiadas e também avaliar o comportamento do óleo de mamona em substituição do glicerol. Neste trabalho, foi realizada a caracterização pela técnica de difração de raios X (DRX), na qual foi calculado o índice de cristalinidade (IC) das blendas não irradiadas e irradiadas, por meio do software Bruker