Materiais de fricção são compósitos cuja matriz polimérica é, usualmente, a resina fenólica novolaca. Os requisitos de desempenho dos materiais de fricção demandam um rígido controle das condições de processamento, na formação de ligações cruzadas da resina fenólica de hexametilenotetramina (HMTA), que definem as propriedades do produto final. Nesta dissertação, resinas fenólicas novolaca pó, com teores de 7, 9 e 11% do agente de cura hexametilenotetramina (HMTA), foram caracterizadas quanto ao peso molecular, além da determinação do comportamento térmico e reológico, objetivando sua aplicação como matriz polimérica em materiais de fricção. Os resultados obtidos, principalmente em função das taxas reacionais obtidas das caracterizações reométricas, indicaram a resina fenólica novolaca com 9% de HMTA, como a melhor para o processamento de material de fricção rápido. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-22T18:37:45Z No. of bitstreams: 1 Dissertacao Albertina Artmann.pdf: 2110638 bytes, checksum: 638291da288591193fe26a9cdeeb5627 (MD5) / Made available in DSpace on 2014-05-22T18:37:45Z (GMT). No. of bitstreams: 1 Dissertacao Albertina Artmann.pdf: 2110638 bytes, checksum: 638291da288591193fe26a9cdeeb5627 (MD5) / Friction materials are composites the polymer matrix of which is usually a novolak phenolic resin. Performance requirements of friction materials demand a steep control of the processing conditions, during crosslinking development of the phenolic resin with hexamethylene tetramine (HMTA), which define the end product properties. In this dissertation, aiming at applyind these materials as a polymer matrix in friction materials, powdered novolak phenolic resins having 7, 9 and 11wt% of hexamethylene tetramine (HMTA) curing agent were characterized as for molecular weight, molecular weight distribution, besides the determination of thermal and rheological behavior. Obtained data based rate of reaction mainly on rheological characterization indicate the 9wt% HMTA novolak phenolic resin for the processing of a typical friction material.

Materiais de fricção são compósitos cuja matriz polimérica é, usualmente, a resina fenólica novolaca. Os requisitos de desempenho dos materiais de fricção demandam um rígido controle das condições de processamento, na formação de ligações cruzadas da resina fenólica de hexametilenotetramina (HMTA), que definem as propriedades do produto final. Nesta dissertação, resinas fenólicas novolaca pó, com teores de 7, 9 e 11% do agente de cura hexametilenotetramina (HMTA), foram caracterizadas quanto ao peso molecular, além da determinação do comportamento térmico e reológico, objetivando sua aplicação como matriz polimérica em materiais de fricção. Os resultados obtidos, principalmente em função das taxas reacionais obtidas das caracterizações reométricas, indicaram a resina fenólica novolaca com 9% de HMTA, como a melhor para o processamento de material de fricção rápido. / Friction materials are composites the polymer matrix of which is usually a novolak phenolic resin. Performance requirements of friction materials demand a steep control of the processing conditions, during crosslinking development of the phenolic resin with hexamethylene tetramine (HMTA), which define the end product properties. In this dissertation, aiming at applyind these materials as a polymer matrix in friction materials, powdered novolak phenolic resins having 7, 9 and 11wt% of hexamethylene tetramine (HMTA) curing agent were characterized as for molecular weight, molecular weight distribution, besides the determination of thermal and rheological behavior. Obtained data based rate of reaction mainly on rheological characterization indicate the 9wt% HMTA novolak phenolic resin for the processing of a typical friction material.

Spritzgießbare Duroplaste zeichnen sich durch hohe thermo-mechanische Beständigkeit, geringe Schwindung und niedrige Materialkosten aus. Damit können die Anforderungen an spritzgegossene Präzisionsbauteile für den Automobilbau erreicht werden. Im Rahmen der vorliegenden Arbeit werden unterschiedliche Novolak-Phenolformmassen hinsichtlich ihres hygroskopischen Verhaltens und dessen Auswirkung auf die Spritzgießverarbeitung und die Bauteilqualität untersucht. Das Absorptionsverhalten kann mithilfe der Fick’schen Diffusionsgesetzte näherungsweise beschrieben werden. Auf Basis von mechanischen Untersuchungen sowie der Beurteilung der Maßhaltigkeit eines Präzisionsdemonstrators hinsichtlich Schwindung und Verzug wird zudem der Einfluss der Prozessparameter beim Spritzgießen bestimmt. Die vorgestellten Untersuchungen zeigen die Grenzen der Verarbeitung und der realisierbaren Bauteilqualität auf, die auf die großserientaugliche Verarbeitung von duroplastischen Bauteilen übertragen werden können. / Injection moldable thermosetting materials show excellent material properties, e.g. high thermo-mechanical resistance and reduced shrinkage in combination with low material cost. Thus, technical requirements for high performance parts for automotive applications can be achieved. In the scope of this work different phenolic novolac compounds were investigated regarding their hygroscopic behavior with its influence for injection molding and product quality. The absorption can be approximately described by Fick’s-Diffusion-Model. The interrelationship of injection molding parameters and the thermo-mechanical behavior is examined on the basis of mechanical testing and the assessment of the dimensional accuracy for a thermoset high precision part. The presented investigations point to the limit of processing and realizable part quality which can be transferred for high performance parts molded in mass production.