RODRIGO SHINZATO
5 resultados
Resultados de Busca
Agora exibindo 1 - 5 de 5
Artigo IPEN-doc 12622 Estudo da influencia do resfriamento na obtenção do PP modificado pela adição do monomero EGDMA2006 - SHINZATO, R.; OTAGURO, H.; LIMA, L.F.C.P.; ARTEL, B.W.H.; PARRA, D.F.; LUGAO, A.B.; YOSHIGA, A.Artigo IPEN-doc 12079 Estudo da viabilidade do processamento pelo método ascendente de diferentes polipropilenos modificados2007 - SANTOS, SIVELTON G.; OTAGURO, HARUMI; LIMA, LUIS F.C.P.; SHINZATO, RODRIGO; LUGAO, ADEMAR B.; FERREIRA, ANA C.B.; NUNES, EDILENE C.D.In the manufacture of tubular films by ascendant method the melt polymer is submitted to strain and elongational flow in the end of matrix. In this process the material must present high values of melt strength to support high shear stress to avoid film rupture. The isotactic polypropylene (iPP) due to the structural characteristics has low melt strength that does not allow this kind of process since the film breaches during stretching. The change in the elongational viscosity of iPP by incorporation of long chain branching or crosslinking improves its performance in this type of process. The aim of this work was to study the viability to production of tubular films by ascendant for different modified polypropylenes.Artigo IPEN-doc 11979 Evaluation of the degradation effect on the processability of high molecular weight polypropylene2007 - SHINZATO, RODRIGO; OTAGURO, HARUMI; LIMA, LUIS F.C.P.; PARRA, DUCLERC F.; ARTEL, BEATRIZ W.H.; LUGAO, ADEMAR B.One way to improve the processability of high molecular weight and melt strength of Polypropylene (PP) is reducing its molecular weight by chain scission with increase of flow index. Nevertheless, the more significant occurrence of chain scission in its structure, further improved its processability is at expense of physical properties. It is well known that the high energy radiation creates free radicals in the polymer chains that subsequently stabilize forming structures. These structures composed by low molecular weight chains and by grafted, branched and crosslinked chains modify the physical and chemical properties of the polymer, depending of their distribution. The low molecular weight chains become from the degradation process by high energy irradiation, which decreases the melt strength and improves its processability. So, this work has the objective to evaluate the degradation of the high molecular weight PP using different irradiation doses. Two kinds of PP samples were utilized. The first one, without additive, presented a flow index of 1.9 g/10 min, and the second, additivated with 0.2 wt % of antioxidant phenolic, Irganox 1010, with a flow index of 0.9 g/10 min. These samples were irradiated with doses of 12.5 and 20.0 kGy. The results of flow index and melt strength obtained with these two kinds of samples showed the antioxidant and the radiation action.Artigo IPEN-doc 15384 Study of polypropylene/polybutene blends modified by gamma irradiation and (High Melt Strength Polypropylene)/polybutene blends2006 - YOSHIGA, ADRIANA; OTAGURO, HARUMI; LIMA, LUIS F.C.P.; ARTEL, BEATRIZ W.H.; PARRA, DUCLERC F.; BUENO, JEFERSON R.; SHINZATO, RODRIGO; FARRAH, MARCELO; LUGAO, ADEMAR B.Artigo IPEN-doc 12269 Study of polypropylene/polybutene blends modified by gamma irradiation and (high melt strength polypropylene)/polybutene blends2007 - YOSHIGA, ADRIANA; OTAGURO, HARUMI; LIMA, LUIS F.C.P.; ARTEL, BEATRIZ W.H.; PARRA, DUCLERC F.; BUENO, JEFERSON R.; SHINZATO, RODRIGO; FARRAH, MARCELO; LUGAO, ADEMAR B.It is well-known that polypropylene (PP) is difficult to process as a consequence of its linear structure. It is also known that grafting of long-chain branches on PP backbone using ionizing radiation is an effective approach to achieve high melt strength polypropylene (HMS PP). Chain-scission and, in minor extend, crosslinking and grafting are the predominant reaction in order to branch PP backbone. However, if multifunctional monomers are used to promote the grafting reaction, crosslinking can surpass chain scission and grafting, reducing drawability. Therefore, in an effort to enhance the processability and so the drawability, it has been found helpful to add a small amount of polybutene-1. Gamma irradiation technique was used to induce chemical changes in blends of PP and polybutene in acetylene atmosphere (crosslinker promoter) and in HMSPP/polybutene blends. The samples were irradiated with a 60Co source with doses of 12.5 and 20 kGy in the presence of acetylene. In this work, two different methods of blends processing were compared regarding rheological and mechanical properties. Effects on the strength and elongation at the yield point and at rupture were observed by mechanical tests and showed decrease of tensile strength and increase of elongation at rupture for samples obtained by irradiation of blends. The results from rheology demonstrated an increase in melt strength and drawability of blends.