Made available in DSpace on 2016-12-12T20:12:31Z (GMT). No. of bitstreams: 1 PGEF15MA038.pdf: 1166149 bytes, checksum: 62e4bee997f4feef09f74999ed38e83d (MD5) Previous issue date: 2015-02-06 / The motivation for the development of this study was the use of an oversize fibers MDF company that had already incorporated resin and paraffin in its structure, for the manufacture of a new product. As a result it would reduce the emission of gases (formaldehyde), because when the raw material is discarded, it can be used .Thus, the objective of this study was to evaluate the technical feasibility of the production of particleboard from oversize fibers taken from the MDF production process through the technological properties of the panels. The raw material which was used, was composed of flake particles, a MDP company, and resin-coated fibers removed before the formation of the mattress of MDF panels, both formed by the mix of Pinus taeda and Pinus elliottii. The experiment involved 14 treatments: 10 treatments with homogeneous panels in the proportions 100 parts of particles to 0 shares fibers, 75:25, 50:50, 25:75, 0: 100, and 4 multi treatments particles in the core, at the fiber surface and the reverse composition. It is noted that each composition was evaluated at two levels of resin, 8% and 12%. Assays were developed in accordance with ASTM D1037 (1993), DIN 52 362 (1982) e NBR 14810 (2006). The results were evaluated by using factor analysis and multiple comparisons with Scott- Knott to 95% probability. In addition, the data were compared with reference standards. As a result, it showed a positive influence of the use of resin-coated oversize fibers and the application of 12% resin in technological properties. Thus, the best study treatments were homogenous panels amount of oversize fibers above 50% and multilayer boards with fibers in the surface layers / A motivação para o desenvolvimento do presente estudo foi a utilização de fibras oversize de uma empresa de MDF que já possuíam incorporadas em sua estrutura resina e parafina, para a fabricação de um novo produto. Em consequência a isso se reduziria a emissão de gases (formaldeído), pelo fato da matéria prima, quando descartada, ser utilizada na geração de energia (queima). Desta forma, o objetivo do presente estudo, foi avaliar a viabilidade técnica da produção de painéis aglomerados a partir de fibras oversize retiradas do processo de produção de MDF por meio das propriedades tecnológicas dos painéis. A matéria-prima utilizada foi composta por partículas flake, de uma empresa de MDP, e fibras resinadas retiradas antes da formação do colchão dos painéis MDF, ambas formadas pelo mix de Pinus taeda e Pinus elliottii. O delineamento experimental envolveu 14 tratamentos, sendo: 10 tratamentos com painéis homogêneos nas proporções 100 partes de partículas para 0 partes de fibras, 75:25, 50:50, 25:75, 0:100, e 4 tratamentos multicamadas com partículas no miolo, fibras na superfície e na composição inversa. Salienta-se que cada composição foi avaliada em dois teores de resina, 8% e 12%. Os ensaios foram desenvolvidos de acordo com a ASTM D1037 (1993), DIN 52362 (1982) e NBR 14810 (2006). Os resultados foram avaliados por meio de análise fatorial e comparação múltipla com Scott-Knott a 95% de probabilidade. Além disso, os dados foram comparados com normas de referência. Como resultados, foi verificada a influência positiva da utilização de fibras oversize resinadas e da aplicação de 12% de resina nas propriedades tecnológicas. Desta forma, os melhores tratamentos do estudo foram compostos por painéis homogêneos com quantidade de fibras oversize acima de 50% e painéis multicamadas com fibras nas camadas superficiais

Les poly(silméthylènesiloxane)s, aussi dénommés silicones hybrides, sont constitués d’un squelette portant un groupement méthylène entre 2 unités SiOSi. La synthèse de ces polymères par polycondensation ne permet pas d’atteindre des masses molaires très élevées, contrairement aux produits issus de la polymérisation par ouverture de cycle. Ce manuscrit décrit la procédure choisie pour aboutir à une synthèse contrôlée de poly(silméthylènesiloxane)s, des précurseurs (monomères, amorceurs) aux polymères. Le monomère cyclique silméthylène a été préparé par cyclisation de le 1,3-dichlorotetraméthylsilméthylène. Ce dernier peut être généré par redistribution de sous-produits de l’industrie de type halogénures d’alkylsilanes. Deux voies de redistribution ont été étudiées, la méthylation par le méthyllithium, et la dismutation des chlorosilanes en présence d’AlCl3 et de tétraméthylsilane. Cette dernière méthode conduit à une nouvelle distribution de chlorosilanes et chlorosilméthylènes jamais obtenue auparavant. La polymérisation par ouverture de cycle en présence d’acide triflique du 1,1,3,3,5,5,7,7-octamethyl-2,6-dioxa-1,3,5,7-tetrasilacyclooctane conduit à des poly(silméthylènesiloxane)s terminés silanol. Suivant la pureté du monomère, différentes masses molaires peuvent être atteintes. La température réactionnelle joue un rôle crucial afin d’éviter toute cyclisation des chaînes. Par comparaison avec des monomères organiques conventionnels (ether, oxiranes, etc...), le mécanisme de polymérisation implique deux espèces en équilibre, un ion silyl-oxonium et un ester silyl-triflate. Une augmentation de la température de réaction déplace cet équilibre vers les espèces ioniques, responsables des réactions de rétroscission. Ainsi la température optimale de réaction a été localisée à 25°C. La polymérisation par ouverture de cycle a été également testée en présence de catalyseur (acide triflique) et d’un amorceur (molécule portant une (des) fonction(s) silanol). Dans les conditions de température données, des polymères de masses molaires et de fonctionnalités contrôlées sont obtenus. Ces expériences ouvrent la porte à de nouvelles voies de polymérisation des cyclosiloxanes, mettant en lumière la compétition entre deux mécanismes de polymérisation, la propagation par bouts de chaînes activés (ACE) et par monomères activés (AM). / Polysilmethylenesiloxanes are belonging to the “hybrid” silicone family. The presence of a methylene group into the polymer backbone enhances their thermal stability, which is particularly interesting in high-tech applications. The synthesis of such polymers by polycondensation did not so far lead to high molar mass polymers, contrary to those prepared by ring-opening polymerization. The synthesis of such polymers is described in this manuscript, from the monomer to the macromolecule. The silmethylene cyclic dimer, the monomer of interest, is synthesized by cyclization of 1,3-dichlorotetramethylsilmethylene. This latter can be generated from the disproportionation of the direct process residue, a by-product of the silicone industry. The disproportionation proceeds either by methylation with methyl lithium, or by Me/Cl interchange reaction catalyzed by AlCl3 in presence of tetramethylsilane. This latter led to a selective dechlorination of chlorosilanes and chlorosilmethylenes in mild conditions, which has not been yet observed with the DPR. Cationic ring-opening polymerization in presence of triflic acid of such silmethylene cyclic dimer led to bis-silanol polysilmethylenesiloxanes. Depending on the purity of monomer, high molar masses can be targeted. The reaction temperature also plays a critical role in order to avoid any cyclization of the growing chains. While triflic acid plays a role of catalyst, it does not allow controlling molar masses. Comparisons with conventional organic monomers were made to identify the polymerization mechanism which involves two propagating species in equilibrium, a silyl-oxonium ion and a silyltriflate ester. An increase of the reaction temperature shifts this equilibrium towards ionic species, responsible of back- and end-biting reactions. Thus the optimal reaction temperature of ROP of the silmethylene cyclic dimer has been set at 25°C previously and confirmed here. The ROP reaction of the silmethylene cyclic dimer in presence of triflic acid and silanol molecule allows designing the obtained molar masses, while keeping a certain control of end-groups. Variations of molar masses with the silanol content speaks for a polymerization occurring through an activated monomer mechanism. Experiments done to confirm this mechanism open routes to the polymerization of other cyclosiloxanes where the competition between the activated chain end (ACE) and the activated monomer (AM) mechanisms could be controlled.