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|Type:||Artigo de periódico|
|Title:||Vinyl ester resin modified with silicone-based additives: III. Curing kinetics|
|Abstract:||Silicone-based additives have been used as fire retardants for thermoplastics with the advantageous of improving the processing and the impact resistance of the polymers. In this work the influence of these additives on the curing kinetics of a vinyl ester resin was studied. Three silicone-based additives were used to modify the properties of the vinyl ester resin. The principal differences between them are the functional groups inserted in the polydimethylsiloxane chains. The additives were dispersed in the resin containing a commonly used mixture of initiator and catalyst methylethyl Ketone peroxide and cobalt-II octanoate, respectively. For some reactional mixtures N,N-dimethylaniline (DMA) was used as promoter. Differential scanning calorimetry (DSC) was used to perform the non-isothermal cure of the non-modified resin and of the resins modified with the additives. Ozawas, Kissingers and Ozawas iso-conversional methods were used to determine the kinetic parameters. For resin cured in absence of DMA the silicone-based additives act as retardants for the curing reaction, a typical diluent effect, while in presence of this promoter the reaction enthalpy as well as the reaction rate were improved. This effect was attributed to specific interactions and reactions between DMA and the silicone-based additives that changed the curing mechanism as well as controlled the phase segregation. (C) 2009 Elsevier Ltd. All rights reserved.|
|Subject:||Vinyl ester resin|
|Editor:||Pergamon-elsevier Science Ltd|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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