Scission
Mostrando 1-12 de 167 artigos, teses e dissertações.
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1. Influence of reaction temperature on the generation of gels during EVA production in tubular reactor
ABSTRACT The fouling formation in the EVA production leads to an increase in the residence time of the material. This result is a favorable condition to generation of the crosslinks during the polymerization. The crosslinking allows raising the molar mass of the polymer, which after the polymerization reaction are characterized as gels, thus generating probl
Matéria (Rio J.). Publicado em: 06/12/2018
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2. Evaluation of Fracture Toughness of Ultraviolet-Irradiated Polycarbonate Using the Essential Work of Fracture Method
The essential work of fracture (EWF) method provides useful parameters to characterize the fracture toughness of polymers exposed to degrading environments under conditions associated with plane-stress state of failure. Exposure of polymeric engineering materials to ultraviolet (UV) radiation may produce macromolecular changes that impair their fracture toug
Mat. Res.. Publicado em: 26/07/2018
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3. Reprocessability of PHB in extrusion: ATR-FTIR, tensile tests and thermal studies
Abstract Mechanical recycling of biodegradable plastics has to be encouraged, since the consumption of energy and raw materials can be reduced towards a sustainable development in plastics materials. In this study, the evolution of thermal and mechanical properties, as well as structural changes of poly(hydroxybutyrate) (PHB) up to three extrusion cycles wer
Polímeros. Publicado em: 29/06/2017
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4. Atmospheric corrosion of Nylon 6,6 in Mauritius
ABSTRACT Plastics are being more and more commonly used for outdoor applications in Mauritius. In this context, the atmospheric corrosion degradation behaviour of nylon 6,6 was observed in the Mauritian atmosphere, having a corrosivity category of C3, according to ISO 9223. The crack width, depth and extent of the cracks formed on the surface were investigat
Matéria (Rio J.). Publicado em: 2016-12
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5. Use of Lead (II) Sulfide Nanoparticles as Stabilizer for PMMA Exposed to Gamma Irradiation
Lead (II) sulfide (PbS) were synthesized by sonochemical method and crystals with cubic structure exhibit aggregated nanoparticles with size in the range of 50-100 nm. Commercial Poly(methyl methacrylate) (PMMA) containing the PbS nanoparticles (PbS-NP) exposed to gamma irradiation were investigated and both the viscosity-average molar mass (Mv) and degradat
Mat. Res.. Publicado em: 2015-04
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6. Photocatalytic degradation of polypropylene/TiO2 nano-composites
In this research, we have investigated the photocatalytic degradation of carbon-coated TiO2 nanoparticles in polypropylene-based nano-composites. For this purpose, polypropylene-based nano-composites were prepared using carbon-coated TiO2 nanoparticles and commercially available TiO2 nanoparticles (Degussa, P25). Our results from SEM, FTIR, and tensile tests
Mat. Res.. Publicado em: 05/08/2014
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7. Kaolin and commercial fcc catalysts in the cracking of loads of polypropylene under refinary conditions
The efficiency of Commercial FCC catalysts (low, medium and high activities) was evaluated by the catalytic cracking process of combined feeds of polypropylene (PP) and vaseline, using a microactivity test unit (M.A.T.) for the production of fuel fractions (gasoline, diesel and residue). The PP/vaseline loads, at 2.0% and 4.0% wt, were processed under refine
Braz. J. Chem. Eng.. Publicado em: 2013-12
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8. UV and gamma irradiation effects on surface properties of polyurethane derivate from castor oil
Gamma and ultraviolet radiation effects on hardness, elastic modulus and viscoelastic properties of polyurethane derived from castor oil (PU) were investigated by nanoindentation tests. Modifications on surface morphology, induced by radiation, were observed by atomic force microscopy. The polyurethane derivate from castor oil shows good resistance to gamma
Polímeros. Publicado em: 21/05/2013
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9. Influence of compatibilizer on blends degradation during processing
The thermomechanical degradation of blends made from polypropylene and polystyrene, with or without compatibilizer, was studied using an internal mixer coupled to a torque rheometer. The blends processed without compatibilizer presented regular and expected results regarding torque reduction, with evidence of chain scission. The blends processed with the blo
Polímeros. Publicado em: 20/02/2013
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10. Direito penal e processo de individuação: um estudo junguiano sobre o impacto das leis penais na sociedade / Criminal law and the process of individuation: a junguian study about the impacto f criminal laws in society
A presente pesquisa tem como objetivo central investigar o impacto das leis penais no processo de individuação, tal como concebido por Carl Gustav Jung. Para tanto, após esclarecidas questões relativas aos pressupostos teóricos da pesquisa junguiana, explorar-se-ão os passos principais do processo de individuação, procurando-se proporcionar uma intro
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/07/2012
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11. Catalisadores à base de platina frente a correntes de H2 contendo acetaldeído geradas via reforma do etanol / Platinum-based catalystic in the face of current H2 containing acthaldehyde generated via reforming of ethanol
Due to the greenhouse effect, hydrogen production from bioethanol reforming is a very important subject in heterogeneous catalysis research. Pt based catalysts are employed in H2 purification processes and also as electrocatalysts of PEM (Proton Exchange Membrane) fuel cells. Hydrogen obtained from ethanol reforming may contain acetaldehyde and small amounts
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/05/2011
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12. Thermo-mechanical degradation and VOC emission of unstabilized and stabilized polypropylene copolymer during multiple Extrusions
The thermo-mechanical degradation during the multi-extrusion of unstabilized and stabilized polypropylene copolymer (cPP) was analyzed using the Chain Scission Distribution Function (CSDF) method. During the first extrusion of unstabilized cPP almost 60% of the initial polymeric chains were submitted to chain scission. The calculations using CSDF show a rand
Materials Research. Publicado em: 08/11/2011