DIONE PEREIRA DE CASTRO
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Artigo IPEN-doc 28985 Thermal degradation and spectroscopy analysis of TPS/PBAT blends irradiated by Cobalt-60 source2022 - CASTRO, D.P.; ANDRADE e SILVA, L.G.This study aimed to prepare blends of natural polymers of TPS with PBAT by reactive extrusion that were subsequently subjected to the irradiation process and evaluated for their thermal and chemical properties. The blends were incorporated with plasticizers (glycerol, castor oil and surfactant) and submitted to the irradiation process using a Cobalt-60 source at a 25 kGy dose and then characterized by FTIR and DSC. The results obtained in the FTIR analysis, the blends did not undergo chemical changes during the irradiation process and thus, maintained their properties. In the DSC analysis, 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 that irradiation using a Cobalt-60 source did not change the properties analyzed and contributed to microbiological protection.Artigo IPEN-doc 27227 Characterization using X-ray diffraction and study of the crystallinity of the thermoplastic starch/poly(butylene adipate-co-terephthalate) blends irradiated by gamma rays2020 - CASTRO, DIONE P. de; GARCIA, RAFAEL H.L.; SILVA, LEONARDO G. de A. eThe 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 non-irradiated 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.Artigo IPEN-doc 26657 Effects of gamma radiation on the properties of the thermoplastic starch/poly (butylene adipate-co-terephthalate) blends2019 - CASTRO, DIONE P. de; SARTORI, MARIANA do N.; SILVA, LEONARDO G. de A. eThe 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 oi l with glycerol in TPS/PBAT blends.