Please use this identifier to cite or link to this item:
|Type:||Artigo de periódico|
|Title:||Sugar Cane Bagasse Lignin As Stabilizer For Rubbers: Part Iii-styrene/butadiene Rubber And Natural Rubber|
De Paoli M.-A.
|Abstract:||The stabilizing effect of a natural antioxidant, sugar cane bagasse-lignin, on the photo-chemical, thermal and environmental degradation of styrene/butadiene rubber and of natural rubber has been studied. For natural rubber the stabilizer was investigated in various concentrations in the pure form and for styrene/butadiene rubber it was also studied in substitution for a hindered phenol in a commercially used formulation which includes a p-phenylenediamine. For the photo-degradation of natural rubber, stabilization becomes appreciable only above a stabilizer concentration of 5·0% whilst in thermal degradation a concentration of 1·0% is sufficient to increase the induction period by a factor of 3 in relation to pure rubber. For styrene/butadiene rubber the same effect occurs; a concentration of 2·0% increases the induction period for photo-degradation by a factor of 1·5 whilst 1·0% increases the induction period for thermodegradation by a factor of 26 in relation to the pure unstabilized rubber. Substitution of the hindered phenol by lignin in the commercial formulation increases the induction period for the thermal degradation by a factor of 6 in relation to the commercial sample. In the environmental ageing experiments the influence of the lower photo-stabilizing effect predominated over the strong thermostabilizing activity of the lignin for both rubbers. © 1985.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.