Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-08-03T11:41:54Z No. of bitstreams: 1 Raiane Valenti Goncalves_Tese de doutorado.pdf: 4511385 bytes, checksum: ab531101c975ccd215f44d53f020cd71 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-08-06T13:49:06Z (GMT) No. of bitstreams: 1 Raiane Valenti Goncalves_Tese de doutorado.pdf: 4511385 bytes, checksum: ab531101c975ccd215f44d53f020cd71 (MD5) / Made available in DSpace on 2018-08-06T14:35:19Z (GMT). No. of bitstreams: 1 Raiane Valenti Goncalves_Tese de doutorado.pdf: 4511385 bytes, checksum: ab531101c975ccd215f44d53f020cd71 (MD5) Previous issue date: 2018-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Due to environmetal and social concerns about synthetic polymers, studies on the preparation of polymers based on renewable sources have been explored by academia and industry. In this context, the use of cashew industry residues rich in phenolic compounds, such as cashew nut shell liquid (CNSL) and its derivative, cardanol, in the synthesis of polymeric materials may be a less aggressive alternative to environment. This work aims to prepare polymeric materials using phenols from the CNSL. The influence of phenols in nanostructured polyaniline (PAni) synthesis were evaluated. Hybrid materials based on PAni doped with cardanol and derivatives of graphene, graphene oxide (GO) and reduced graphene oxide (rGO), were also prepared. In addition, the influence of cardanol and PAni doped with cardanol on the thermal properties of benzoxazine resins was investigated. The polymeric materials were characterized by FTIR, UV-vis, FESEM, TEM, XRD, TGA, DSC and four-point methodology for determination of electrical conductivity. From these results, it was found that cardanol and CNSL acted as primary dopants in the synthesis of conductive PAni (electrical conductivity in order 10-1 S.cm-1). CNSL acted as soft template and plasticizer for the conventional synthesis of nanofibers PAni doped with hydrochloric acid. The methodology developed for preparation of cardanol doped PAni combined with both GO and rGO was able to prepare conductive (electrical conductivity in order 100 S.cm-1) and nanostructured hybrid materials. Furthermore, cardanol and PAni doped with cardanol were incorporated into the benzoxazine matrix to form materials with thermal stability and crosslink density greater than those of the benzoxazine resin. / Devido ?s preocupa??es ambientais e sociais relacionadas aos pol?meros sint?ticos, os estudos sobre a prepara??o de pol?meros derivados de fontes renov?veis t?m sido explorados pela academia e ind?stria. Dentro desse contexto, o uso de res?duos da ind?stria do caju ricos em compostos fen?licos, tais como, o l?quido da casca da castanha de caju (LCC) e o seu derivado, o cardanol, na s?ntese de materiais polim?ricos pode ser uma alternativa menos agressiva ao meio ambiente. Este trabalho visa preparar materiais polim?ricos empregando fen?is provenientes do LCC. A influ?ncia da presen?a dos fen?is na s?ntese da polianilina (PAni) nanoestruturada foi avaliada. Materiais h?bridos baseados em PAni dopada com cardanol e derivados do grafeno, ?xido de grafeno (OG) e ?xido de grafeno reduzido (OGR), tamb?m foram preparados. Ainda, foi investigada a influ?ncia do cardanol e da PAni dopada com cardanol nas propriedades t?rmicas das resinas benzoxazinas. Os materiais polim?ricos foram caracterizados por FTIR, UV-vis, MEV-FEG, MET, DRX, TGA, DSC e metodologia de quatro pontas para determina??o de condutividade el?trica. A partir dos resultados, foi constatado que o cardanol e o LCC atuaram como dopantes prim?rios nas s?nteses de PAni condutiva (condutividade el?trica na ordem 10-1 S.cm-1). Al?m disso, o LCC atuou como soft template e plastificante para as s?nteses convencionais de nanofibras de PAni dopadas com ?cido clor?drico. A metodologia desenvolvida para o preparo de PAni dopada com cardanol combinada tanto com OG quanto com OGR foi capaz de preparar materiais h?bridos nanoestruturados e condutores (condutividade el?trica na ordem 100 S.cm-1). Ainda, cardanol e PAni dopada com cardanol foram incorporados a matriz de benzoxazina formando materiais com estabilidade t?rmica e densidade de reticula??o superiores ?quelas t?picas da resina benzoxazina.

The most important safety device for commercial vehicles is the brake system. It has to satisfy multiple requirements such as braking performance, wear resistance and low noise production. In the last years, a further requirement has been gaining increasing attention: their particulate matter emission. Indeed, brake systems are one of the most relevant sources of non-exhaust traffic-related emission PM. These emissions have been shown to negatively affect both the environment and the human health, urging authorities to take legislative action. This work is focused on improving the sustainability aspects of brake friction materials. This was done by following two different approaches, both of which involved the use of alternative ingredients in the friction material composition. The new ingredients were chosen based on their properties while also considering aspects related to an eventual industrial application. The first approach involved the use of a natural ingredient, rice husk, as an ingredient in the composition of friction materials; whereas the second approach dealt with the substitution of the conventional phenolic resin binder with benzoxazine resins. The tribological and PM emission properties of friction material samples produced using these ingredients were investigated via tribological testing, and were correlated to the results of the characterization analyses that were performed on the worn surfaces, on the collected emitted particles, and on the newly adopted ingredients themselves. Rice husk is a widely available byproduct of the agricultural industry, and possesses some peculiar properties related to its considerable inorganic content that separates it from the other lignocellulosic materials. Friction materials modified with rice husk were tested with a Pin-on-Disc tribometer and with a reduced-scale dynamometric bench while also monitoring their PM emission. Overall, the adoption of rice husk showed promising results, preserving the friction material coefficient of friction, PM emission and wear resistance. However, when higher temperatures were reached, a loss of performance and durability was observed. Nevertheless, this temperature range was above that associated to common LDV brake system operation, which this application is targeted to. Benzoxazine resins are a relatively new class of binders that display some attractive properties when compared to the conventionally used phenolic resins, such as more forgiving storage conditions, improved thermal stability and customizability of their properties. Two of the simplest representatives of the benzoxazine resin family were hereby adopted. An initial characterization of the thermal behaviour of the resins was first carried out to design the production process of the friction materials containing them. Friction materials bound by benzoxazine resins and by a commercial phenolic resin were tested by Pin-on-Disc and reduced-scale dynamometric bench testing while monitoring their PM emission production. The substitution of phenolic resin with benzoxazine resin as friction material binder proved to be successful, leading to lower wear of the samples, which would translate to a lower environmental impact.