Orientador: Aldo Eloizo Job / Banca: Sílvio Rainho Teixeira / Banca: Francisco Eduardo Gontijo Guimarães / Banca: Marcelo Mulato / Banca: Anderson Rodrigues Lima Caires / O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp / Resumo: Compósitos condutores são materiais preparados para combinar as propriedades físicas dos polímeros com partículas condutivas. Neste trabalho, são apresentadas a preparação e caracterização de compósitos condutores contendo borracha natural (BN), raspa de couro (RC) e negro de fumo (NF). As Amostras foram conformadas em diferentes percentuais em massa dos constituintes BN, RC e NF: 38/60/2.0; 37.5/60/2.5; 37/60/3.0 e 36.5/60/3.5, respectivamente, aplicando uma pressão de 12 toneladas durante o 5 minutos à temperatura de 160°C, resultando em membranas com boa qualidade e com a espessura desejada. Os compósitos BN/RC/NF foram caracterizados por microscopia óptica (MO), microscopia eletrônica varredura (MEV), Microscopia de Força Atômica (AFM), espectroscopia Raman e infravermelho, termogravimetria (TG), calorimetria exploratória de varredura (DSC), análise dinâmico mecânica (DMA), testes mecânicos (Tensão versus deformação) e medidas de condutividade elétrica. A presença do NF no compósitos BN/ RC/NF, promoveu uma condutividade elétrica da ordem de 1.5x10-3 S.cm-1. Os ensaios mecânicos mostram que o compósito BN/RC/NF possui propriedades físicas intermediárias entre as membranas de BN e o couro. Verificou-se que as membranas do compósito BN/RC/NF são de baixo custo, e podem ser facilmente preparadas. Estes compósitos apresentaram boa estabilidade térmica, adequadas propriedade mecânica e condutividade elétrica, e são apropriadas para produzir luvas, mantas e pisos antiestáticos. Além disso, o compósito BN/RC/NF são obtidos a partir de resíduos de curtumes de couro contribuindo para a redução de um problema ambiental. / Abstract: Conductive composites are materials prepared combining the physical properties of polymers and conductive particles. In this work the preparation and characterization of conducting composites containing natural rubber (NR), leather residue (LR) and carbon black (CB) are presented. Samples were conformed in different percentages of mass of the NR, LR and CB constituents: 38/60/2.0; 37.5/60/2.5; 37/60/3.0 and 36.5/60/3.5, respectively, applying a pressure of 12 tons during 5 minutes at the temperature of 160°C, resulting in membranes with good quality and with the desired thickness. The NR/LR/CB composites were characterized using optical microscopy (OM), scanning electronic microscopy (SEM), atomic force microscopy (AFM), Raman and infrared spectroscopy, thermogravimetry (TG), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), mechanical test (stress vs. strain) and he electric conductivity measurements. The presence of the CB in composites NR/LR/CB provided an electric conductivity of the order of 1.5x10-3 S.cm-1. Mechanical tests show that the NR/LR/CB composites have intermediate properties between the membranes of NR and the leather. It was found that NR/LR/CB membranes can be easily prepared with very low cost. They presented good thermal stability, adequate mechanical and electric conductivity properties that are appropriate to produce gloves, blankets and antistatic floors. In addition, the NR/LR/CB composites are obtained from leather residues from tanneries contributing for the reduction of an environmental problem. / Doutor

Este trabalho teve como objetivo o desenvolvimento, avaliação e caracterização de compósitos com matriz polimérica de polietileno de alta densidade (HDPE) e com madeira de Pinus taeda, alumina calcinada e agentes compatibilizantes. Foram desenvolvidos compósitos com um ou dois componentes incorporados à matriz polimérica e realizada a análise das propriedades mecânicas, morfológicas, dinâmico-mecânicas e térmicas destes compósitos. Preliminarmente foram desenvolvidas vinte e seis formulações com granulometrias diversas para suas cargas, percentuais de pó de madeira variados e dois tipos de agentes compatibilizantes. Após ensaios mecânicos realizados com estas vinte e seis formulações elegeram-se as que apresentaram os maiores valores para a propriedade de resistência a flexão e deu-se continuidade ao restante dos ensaios. Utilizou-se o processo de extrusão para obtenção de pellet's homogeneizados dos compósitos e moldou-se os corpos de prova em processo de injeção. Os resultados diferenciados para as propriedades mecânicas foram obtidos com as composições com o percentual maior de madeira e dois componentes simultaneamente, sendo que o compósito PE24M4A2MA (70% HDPE, 24% madeira, 4% alumina, 2% HDPE-g-MA) apresentou valores superiores ao do HDPE puro em 41% na resistência à tração e 101% na resistência à flexão, e a composição PE19M9A2MA (70% HDPE, 19% madeira, 9% alumina, 2% HDPE-g-MA) apresentou valores superiores ao do HDPE puro em 34,6% na resistência à tração e 81,30% na resistência à flexão. Nas micrografias observou-se a interação entre a carga vegetal e a matriz polimérica, e a interação parcial da carga mineral e a matriz. Para os módulos de armazenamento e de perda das propriedades dinâmico-mecânicas os resultados superiores também foram obtidos com os compósitos com maior teor de carga vegetal, sendo que o compósito PE24M4A2MA permitiu a obtenção do maior módulo de armazenamento e de perda nas regiões e em comparação com o HDPE e os outros compósitos. A viscosidade do material tendeu a aumentar com a incorporação de cargas, tanto vegetal quanto mineral durante o processo de extrusão e no ensaio de reologia, sendo que os compósitos com maior teor de madeira apresentaram maior viscosidade, provavelmente devido à interação mais efetiva do pó de Pinus taeda com a matriz polimérica. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-09-14T14:24:50Z No. of bitstreams: 1 Dissertacao Karine Grison.pdf: 2981635 bytes, checksum: f54bb79e364f709485a4d8478b814b72 (MD5) / Made available in DSpace on 2015-09-14T14:24:50Z (GMT). No. of bitstreams: 1 Dissertacao Karine Grison.pdf: 2981635 bytes, checksum: f54bb79e364f709485a4d8478b814b72 (MD5) / This work aimed at the development, evaluation and characterization of polymer matrix composites with high density polyethylene (HDPE) and wood of Pinus taeda, calcined alumina and compatibilizers. Composites have been developed with one or two components incorporated into the polymer matrix and conducted the analysis of the mechanical, morphological, dynamicmechanical and thermal properties of these composites. Preliminarily been developed twenty-six formulations with different granulometry to their loads, varying percentages of wood flour and two types of coupling agents. After mechanical tests with these twenty-six formulations were elected those who had the highest values for bending resistance property and was continued with the rest of the tests. We used the extrusion process to obtain pellet homogenized's composites and molded into test specimens injection process. The different results for mechanical properties were obtained for compositions with higher percentage of wood and two components simultaneously, and that the composite PE24M4A2MA (70% HDPE, 24% wood, 4% alumina, 2% HDPE-g-MA) had values higher than the pure HDPE by 41% in tensile strength and 101% in flexural strength, and PE19M9A2MA composition (70% HDPE, 19% wood, 9% alumina, 2% HDPE-g-MA) was higher for the HDPE pure at 34.6% in tensile strength and 81.30% in flexural strength. All micrographs observed interaction between natural charge and the polymer matrix, and partial interaction of filler and matrix. For the storage modulus and loss of dynamic mechanical properties superior results were also obtained with the composites with higher vegetable filler content, wherein the composite PE24M4A2MA afforded the highest storage modulus and the loss in the regions and compared with HDPE and other composites. The viscosity of the material tended to increase with the incorporation of fillers, both natural and mineral during the extrusion process and the rheology test, and wood composites with higher content showed higher viscosity, probably due to more effective interaction of powder Pinus taeda with the polymeric matrix.

Orientador: Edson Cocchieri Botelho / Coorientador: Pedro Carlos de Oliveira / Banca: Geraldo Mauricio Cândido / Banca: Evandro Luis Nohara / Banca: Gerson Marinucci / Banca: Sandro Campos Amico / Resumo: Durante o século XX os materiais compósitos estruturais receberam especial atenção dos pesquisadores, o que levou a uma rápida evolução tecnológica acarretando uma intensa procura e posterior obtenção de materiais com características mecânicas cada vez mais elevadas, principalmente no que diz respeito ao módulo de elasticidade e a resistência mecânica. Dessa forma, os materiais tradicionalmente aplicados em engenharia aeroespacial, como o aço e o alumínio entre outros, vêm sendo substituídos por uma nova classe de materiais denominada materiais compósitos, em particular os de matrizes poliméricas reforçadas com fibras contínuas, em resposta à impossibilidade de aumento de resistência e tenacidade nos materiais homogêneos associado a redução de massa específica. Entretanto, devido às aeronaves operarem em uma grande variedade de condições ambientais tais como: ar frio e seco, em condições quentes e úmidas e diferentes gradientes de temperatura, estas condições adversas sempre devem ser consideradas na utilização de materiais aeronáuticos. Portanto, torna-se extremamente importante a avaliação da resistência às intempéries por parte dos materiais a serem selecionados para aplicações estruturais, principalmente em estruturas primárias. Dentro desse contexto, o objetivo do presente trabalho foi avaliar a influência da temperatura e umidade em laminados de aplicação aeronáutica (PPS/fibras de carbono e epóxi/fibras de carbono), a partir da exposição desses materiais a ambientes agressivos (câmaras higrotérmica, de ciclagem térmica e de choque térmico) e, posteriormente, estudar a degradação das suas propriedades mecânicas por meio de ensaios de tração, compressão e cisalhamento interlaminar e das suas propriedades térmicas utilizando-se das técnicas de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: During the 20th century the structural composites received special attention of the researchers leading to the very fast technological development of such materials. This way, occurred the preparation of materials with good mechanical properties, mainly concerning high mechanical strength and stiffness. So, the materials usually applied in aeronautical engineering, as steel and aluminium among others, have been substituted by a new class of materials, named composite materials, particularly polymeric matrix reinforced with continuous fibers answering the difficulty in increasing of mechanical strength and toughness in the homogeneous materials. Therefore, because the aircraft are always operating under different environment conditions such as dry and cold air, warm and wet conditions and large cyclical variations of temperature, these conditions have to be taken into consideration in the utilization of the aeronautical materials. However, it is extremely important the evaluation of the resistance of the materials to the intemperate weather to be selected for structural applications, mainly as primary structures. In this context the aim of this work was the evaluation the influence of intemperate weather in the laminates of aeronautical application (PPS/carbon fiber and epoxy/carbon fiber), submitting these materials to aggressive environment and study the degradation of their mechanical properties by tensile, compression and interlaminar shear tests as well as thermal properties by DMA and TMA. From these found results, it was observed that for PPS/carbon fiber laminates no one used conditioning generate significant differences in the glass transition temperature nor on the mechanical performance of its composite, qualifying this laminate for aeronautical application when its necessary this kind of requirements... (Complete abstract click electronic access below) / Doutor

Orientador: Maria Odila Hilario Cioffi / Co orientador: Herman Jacobus Corneli Voorwald / Banca: Mirabel Cerqueira Rezende / Banca: Sandro Donnini Mancini / Banca: Laura Hecker de Carvalho / Banca: Gerson Marinucci / Resumo: O desenvolvimento de compósitos formados por matrizes poliméricas e reforçados com fibras naturais ganhou notável interesse na pesquisa, a partir da década de 90. A elevada demanda por compósitos, aliada à regulamentação das leis ambientais, tornou indispensável o aperfeiçoamento e o desenvolvimento de técnicas de processamento menos poluentes, com a utilização de matérias-primas provenientes de fontes naturais e, consequentemente, com menor custo envolvido. Esta pesquisa dá continuidade aos estudos do mestrado e se fundamenta no desenvolvimento do compósito polimérico com matriz de resina epóxi reforçado por fibras naturais de sisal, para uso como material de reforço em estruturas de madeira cuja integridade esteja afetada. Diante do exposto, esta pesquisa envolve o desenvolvimento e o estudo do comportamento do compósito sisal/epóxi processado via moldagem por transferência de resina (RTM). A caracterização das matérias-primas empregadas na preparação do compósito ocorreu pela determinação da massa específica, da porosidade do tecido, das análises térmicas por meio das técnicas de termogravimetria (TGA), calorimetria exploratória diferencial (DSC) e análise dinâmico-mecânica (DMA), pelas resistências à tração e à flexão e também pelo estudo da permeabilidade do tecido de sisal. Em sequência, o trabalho apresenta o processamento e as caracterizações térmicas, físicas e mecânicas de laminados planos do compósito de matriz epóxi reforçada com duas camadas do tecido plain-weave de sisal, processados via RTM. Os laminados obtidos foram ensaiados em tração, flexão, ultrassom (C-Scan), TGA, DSC, DMA, além da determinação da massa específica. As análises termogravimétricas indicaram que a temperatura inicial de degradação do compósito é de 182ºC. A Tg - temperatura de transição vítrea, determinada por DSC e por DMA, é de 49,0oC e 45,2oC... / Abstract: Polymeric composites reinforced with natural fibers has obtained considerable interest in the research area, when from the 90's, the high demand by composites and with the environmental laws regulation become indispensable the improvement and development of processing techniques with less pollutants, that involves the use of raw materials from natural sources and, therefore, with low cost. The objective of this work is continue a research line beginning in the master's studies, that is based on the polymeric composite development using epoxy resin reinforced with natural sisal fibers, to apply as reinforcement to restore timber structures, whose integrity was affected. So, this research proposes to develop the sisal/epoxy composite, processed by resin transfer molding (RTM) and to characterize the raw materials, regarding to density, thermal analysis techniques using thermogravimetry (TGA/DTG), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), mechanical tests as tensile and flexural and permeability of the woven sisal fabric. Subsequently, the epoxy/two layers of woven plain-weave sisal laminated composite was scanned by ultrasound and characterized with respect of thermal analysis, physical and mechanical characterizations. Thermogravimetry analysis suggests that the onset degradation temperature of composite is 182°C. The glass transition temperature (Tg), determined from DSC and DMA, is 49.0°C and 45.2°C, respectively. The mechanical tests showed values of 36 MPa for tensile strength, 75 MPa for flexural strength, 2.19 GPa for tensile modulus and 3.86 GPa for flexural ... / Doutor

Este trabalho teve como objetivo o desenvolvimento, avaliação e caracterização de compósitos com matriz polimérica de polietileno de alta densidade (HDPE) e com madeira de Pinus taeda, alumina calcinada e agentes compatibilizantes. Foram desenvolvidos compósitos com um ou dois componentes incorporados à matriz polimérica e realizada a análise das propriedades mecânicas, morfológicas, dinâmico-mecânicas e térmicas destes compósitos. Preliminarmente foram desenvolvidas vinte e seis formulações com granulometrias diversas para suas cargas, percentuais de pó de madeira variados e dois tipos de agentes compatibilizantes. Após ensaios mecânicos realizados com estas vinte e seis formulações elegeram-se as que apresentaram os maiores valores para a propriedade de resistência a flexão e deu-se continuidade ao restante dos ensaios. Utilizou-se o processo de extrusão para obtenção de pellet's homogeneizados dos compósitos e moldou-se os corpos de prova em processo de injeção. Os resultados diferenciados para as propriedades mecânicas foram obtidos com as composições com o percentual maior de madeira e dois componentes simultaneamente, sendo que o compósito PE24M4A2MA (70% HDPE, 24% madeira, 4% alumina, 2% HDPE-g-MA) apresentou valores superiores ao do HDPE puro em 41% na resistência à tração e 101% na resistência à flexão, e a composição PE19M9A2MA (70% HDPE, 19% madeira, 9% alumina, 2% HDPE-g-MA) apresentou valores superiores ao do HDPE puro em 34,6% na resistência à tração e 81,30% na resistência à flexão. Nas micrografias observou-se a interação entre a carga vegetal e a matriz polimérica, e a interação parcial da carga mineral e a matriz. Para os módulos de armazenamento e de perda das propriedades dinâmico-mecânicas os resultados superiores também foram obtidos com os compósitos com maior teor de carga vegetal, sendo que o compósito PE24M4A2MA permitiu a obtenção do maior módulo de armazenamento e de perda nas regiões e em comparação com o HDPE e os outros compósitos. A viscosidade do material tendeu a aumentar com a incorporação de cargas, tanto vegetal quanto mineral durante o processo de extrusão e no ensaio de reologia, sendo que os compósitos com maior teor de madeira apresentaram maior viscosidade, provavelmente devido à interação mais efetiva do pó de Pinus taeda com a matriz polimérica. / This work aimed at the development, evaluation and characterization of polymer matrix composites with high density polyethylene (HDPE) and wood of Pinus taeda, calcined alumina and compatibilizers. Composites have been developed with one or two components incorporated into the polymer matrix and conducted the analysis of the mechanical, morphological, dynamicmechanical and thermal properties of these composites. Preliminarily been developed twenty-six formulations with different granulometry to their loads, varying percentages of wood flour and two types of coupling agents. After mechanical tests with these twenty-six formulations were elected those who had the highest values for bending resistance property and was continued with the rest of the tests. We used the extrusion process to obtain pellet homogenized's composites and molded into test specimens injection process. The different results for mechanical properties were obtained for compositions with higher percentage of wood and two components simultaneously, and that the composite PE24M4A2MA (70% HDPE, 24% wood, 4% alumina, 2% HDPE-g-MA) had values higher than the pure HDPE by 41% in tensile strength and 101% in flexural strength, and PE19M9A2MA composition (70% HDPE, 19% wood, 9% alumina, 2% HDPE-g-MA) was higher for the HDPE pure at 34.6% in tensile strength and 81.30% in flexural strength. All micrographs observed interaction between natural charge and the polymer matrix, and partial interaction of filler and matrix. For the storage modulus and loss of dynamic mechanical properties superior results were also obtained with the composites with higher vegetable filler content, wherein the composite PE24M4A2MA afforded the highest storage modulus and the loss in the regions and compared with HDPE and other composites. The viscosity of the material tended to increase with the incorporation of fillers, both natural and mineral during the extrusion process and the rheology test, and wood composites with higher content showed higher viscosity, probably due to more effective interaction of powder Pinus taeda with the polymeric matrix.

D.Phil. (Chemistry) / Polycaprolactone (PCL), a linear, biodegradable polymer, and ethylene vinyl acetate (EVA), a branched copolymer, were used to prepare PCNs via the melt-blending method. Organoclay of the type Cloisite® 20A (C20A) and bentonite clay were used as fillers. The results show that the structure of a polymer matrix plays a significant role towards compatibilisation with the silicate layers of the clay. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed an exfoliated-intercalated mixed morphology for the PCL matrix. However, for the EVA matrix, silicate layers agglomerated to form tactoids and resulted primarily in an intercalated morphology. Fourier transform infrared (FT-IR) spectroscopy was used to determine the nature of the interactions between the polymer and the filler. The thermal properties were investigated using thermogravimetric analysis (TGA) and indicated that, with an increase in clay loading, the thermal stability was reduced for both matrices, notwithstanding the type of polymer or clay used. Using EVA and C20A, this study revealed that more exfoliated nanocomposite structures can be obtained by using a modified solution-blending technique. This technique is a hybrid of the melt-blending and solution-blending methods. When compared to the melt-blending method, the modified solution method was found to be an efficient method for producing nanocomposite strips with uniform dispersion of the clay at organoclay loading of 8% and crystallinity by extrusion. However, the melt-blending method produced nanocomposites with high porosity, intercalation and thermal stability whereas the modified solution-blending technique resulted in more intercalated-exfoliated morphology, but less porosity and thermal stability. Despite the positives drawn from the modified solution method, the melt-blending method was used throughout for nanocomposites intended for application in water treatment. This was done because the solution used in the modified solution method could not be completely removed from the nanocomposite. Organic solvents can have a negative effect on the environment and human life.

Ph.D. (Chemistry) / The ultrafiltration membranes presented in this study were synthesized using the phase inversion method by casting on a nonwoven fabric. The polymer solutions were mixed with synthetic and bio additives in order to improve the resultant membrane performance. Synthetic additives (polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP)) were compared with a novel and cheap bio additive, lignin. Based on the knowledge that the additives must be soluble in water in order to increase the pore sizes of the membranes, sodium hydroxide was used to elute residual additives that remain in the membrane during coagulation. In order to trace the residual additives remaining, ATR-FTIR was used. Contact-angle analysis and water-absorption experiments were used to elucidate the hydrophilic properties of the prepared membranes. Membranes modified with lignin (Lig) were found to absorb more water (94% water uptake) when compared to the other membranes. In general, the contact angles were found to be low for membranes that were treated with NaOH. Membrane permeability followed the trend, Lig_PSf>PVP_PSf>PEG_PSf which is similar to the trend followed during water uptake. Pore size and pore distribution analysis showed that membranes modified with lignin and PVP had a narrow range (had pore sizes ranging from 10 to 24 nm) compared to that of PEG-PSf membrane (which ranged from 2.5 to 22 nm). A Robeson plot showed that Lig_PSf membranes had high separation factors regardless of the size of the solute being rejected. This study shows the possibility of using cheap and readily available additives to increase the performance of membranes......

The concept of a unique ceramifiable Ethylene vinyl acetate (EVA) based polymer composite was based on the incorporation of inorganic compounds such as aluminium hydroxide, calcium carbonate, muscovite mica, and calcined kaolinite within a 95 percent EVA/ 5 percent Polydimethylsiloxane (PDMS) polymer matrix such tha t upon heating to elevated temperatures of about 1000 oC, a solid end-product with ceramic-like properties would be formed. The ceramifiable EVA based polymer composite was developed to be used as electric cable insulation or sheath as the formation of a ceramic based material at elevated temperatures would provide flame retardant properties during fire situations. The flame retardant properties at elevated temperatures would ensure that the insulation remains at such temperatures due to some of the properties of the resultant ceramic such as reasonably high flexural strength, high thermal stability, non-reactivity and high melting point. During a fire this would ensure that flames would not be propagated along the length of the cable and also protect the underlying conducting wires from being exposed to the high temperatures of the fire. Its application as a cable insulation also required that the material functions as a cable insulator under ambient temperature conditions where the ceramifiable polymer composite should retain certain polymer properties such as the post-cure tensile strength (MPa), degree of polymer elongation (percent), thermal expansion, thermal slacking, limited oxygen index and electrical insulation. This study made use of a composite experimental design approach that would allow for the optimization of the amounts of the additives in the ceramifiable polymer composite giving both the desired mechanical properties of the material under normal operating temperatures as a polymer and also as a ceramic once exposed to elevated temperatures. The optimization of additives used in the ceramifiable polymer composite was done by using a D-optimal mixture design of experiments (DoE) which was analyzed by multiple linear regression.

Aqueous dispersion prepregging, a relatively new method for forming graphite reinforced, polymer matrix composites, was investigated. This methodology could circumvent many of the environmental and processing problems prominent in the current state of the art. Aqueous dispersion prepregging requires that the matrix resin be in the form of a stable colIoidal dispersion, preferably of small uniform particles. Formation of submicron particles from poly(ether ether ketone) (PEEK) for use in aqueous dispersion prepregging was demonstrated. The procedure involved synthesis 4,4'-difluoro (N-benzohydroxylidene aniline) followed by the step polymerization of this monomer and hydroquinone via aromatic nucleophilic substitution to 'form an amorphous PEEK derivative, poly(ether ether ketimine). This monomer can also be statistically copolymerized with 4,4'-difluorobenzophenone to afford a semicrystalline, soluble PEEK derivative. Acid catalyzed hydrolysis of these derivatives to insoluble PEEK can be used to generate submicron particles. A high performance stabilizer, which was used for suspending PEEK particles in water, has also been developed. This facilitated the development of processes for aqueous dispersion prepregging. The stabilizer is a poly(arylene ether) copolymer formed from 4,4'-difluoro- (N-benzohydroxylidene aniline), 2,6-dichloropyridine, and hydroquinone. Poly{ ether ether ketone) has excellent mechanical properties as well as solvent resistance. However, it has been reported that under the recommended high temperature melt processing conditions the material may degrade via branching and crosslinking. An alternative to melt processing PEEK is to apply the powder metallurgy technique of sintering. This involves cold (room temperature) compaction of the polymeric powder, followed by pressure free sintering of the resultant green body. Sintering occurs due to a reduc1tion of surface free energy, and in this regard small particles (large surface area) have a large driving force for sintering. Pressure free sintering of PEEK par1icles with emphasis on the development of mechanical properties such as stiffness and strength as a function of sintering time, temperature, and particle size was examined. The data was analyzed using the two particle model developed by Frenkel and the crack healing theory developed by Wool. The latter is based on the reptation theory of de Gennes and Doi and Edwards. Sintering conditions were established which allowed for the attainment of comparable mechanical behavior to conventional processes. / Ph. D.

No description available.