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|Type:||Artigo de periódico|
|Title:||Eucalyptus Tar Pitch Substitution of Phenol in the Preparation of Novolak-Type Resins Cured with Hexamethylenetetramine|
|Abstract:||Wood tar pitch, sometimes referred to as biopitch, is the residue from the distillation of tar recovered during charcoal making processes. The biopitch from Eucalyptus tar, which has guaiacyl and syringyl units in its molecular structure, exhibits novolak behavior and this phenolic oligomer can be cured with hexamethylenetetramine (HMTA). In this work, mixtures of commercial phenolic resins and Eucalyptus tar pitch were cured and characterized by infrared spectroscopy, elemental and thermogravimetric analyses. Their acetone-in soluble contents were determined and their electrical properties were investigated. The effects of pitch and HMTA contents on phenolic resin properties were modelled using statistical techniques. The regions of optimum formulations were indicated. The results showed that pitch decreases the thermal stability and the acetone-insoluble content of the phenolic blends, whereas HMTA addition had an opposite effect. The statistical model applied indicated that, in terms of acetone-insoluble content, phenolic resin can be substituted for pitch up to a composition of 50 wt%. Electrical studies showed that pitch-phenolic blends have insulating properties.|
|Editor:||Chemical Soc Japan|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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