Thermal degradation during composite fabrication is the main impediment for the wide use of agro-based fibers as filler and reinforcement in engineering thermoplastic composites. Different thermal, chemical and physical techniques (e.g., alkali, steam explosion and retting) aiming to increase the fiber-matrix adhesion or reduce the plant fibers water absorption have been presented in the literature. However, there have been very few attempts to solve the difficulties associated with processing engineering thermoplastics with plant fibers. Most of these attempts involved the use of additives (such as plasticizers and salts) to lower the polymers processing temperature and plant fibers with inherent higher thermal stability (such as Curaua and cellulose). Despite all these efforts, no important progress has been achieved. Therefore, to explore the full potential of wheat straw and expand its use in commercial applications, an experimental study was carried out to develop different methodologies to improve the thermal stability of wheat straw fiber. In this thesis, most attention is given to wheat straw because of the relevance and potential of entering the market as commercial filler today. It is reported here that the thermal stability and chemical composition of wheat straw do not seem to significantly vary with wheat straw type and cultivation region. For example, the main thermal degradation of wheat straw samples starts in a narrow window of temperature which goes from 220.8 to 237.8 °C and from 224.8 to 238.1 °C for air and nitrogen atmospheres, respectively. On the other hand, lignin and inorganic materials are the wheat straw components with the highest relative variation. In addition, it is showed here that silane modification is an efficient method to increase the temperature of degradation of wheat straw. The highest improvements were achieved with chlorosilane modifiers and combinations of alkoxysilane and chlorosilane modifiers. In fact, the silane treated samples have lower thermal degradation during the fabrication of composites with polyamide-6. It is observed here that the extruded and injection molded composites containing silane treated wheat straw samples have significant smaller thermal degradation than those utilizing untreated wheat straw samples. Equally important, it seems that the mechanical properties of the composites are not affected by the addition of silane treated samples in comparison with untreated wheat straw. In addition, another efficient treatment method is presented in this thesis. This method employs ultraviolet light to modify and improve the thermal stability of wheat straw. This method offers important economical and environmental benefits. Significant improvements (e.g., 40 ºC increase on the temperature at 2% of weight loss) were achieved after treatment for short periods of time (up to 15 minutes) and without the use of any pre-treatment or production of toxic by-products. This treatment method represents a novel application for ultraviolet light with potential for industrial use.

Thermal degradation during composite fabrication is the main impediment for the wide use of agro-based fibers as filler and reinforcement in engineering thermoplastic composites. Different thermal, chemical and physical techniques (e.g., alkali, steam explosion and retting) aiming to increase the fiber-matrix adhesion or reduce the plant fibers water absorption have been presented in the literature. However, there have been very few attempts to solve the difficulties associated with processing engineering thermoplastics with plant fibers. Most of these attempts involved the use of additives (such as plasticizers and salts) to lower the polymers processing temperature and plant fibers with inherent higher thermal stability (such as Curaua and cellulose). Despite all these efforts, no important progress has been achieved. Therefore, to explore the full potential of wheat straw and expand its use in commercial applications, an experimental study was carried out to develop different methodologies to improve the thermal stability of wheat straw fiber. In this thesis, most attention is given to wheat straw because of the relevance and potential of entering the market as commercial filler today. It is reported here that the thermal stability and chemical composition of wheat straw do not seem to significantly vary with wheat straw type and cultivation region. For example, the main thermal degradation of wheat straw samples starts in a narrow window of temperature which goes from 220.8 to 237.8 °C and from 224.8 to 238.1 °C for air and nitrogen atmospheres, respectively. On the other hand, lignin and inorganic materials are the wheat straw components with the highest relative variation. In addition, it is showed here that silane modification is an efficient method to increase the temperature of degradation of wheat straw. The highest improvements were achieved with chlorosilane modifiers and combinations of alkoxysilane and chlorosilane modifiers. In fact, the silane treated samples have lower thermal degradation during the fabrication of composites with polyamide-6. It is observed here that the extruded and injection molded composites containing silane treated wheat straw samples have significant smaller thermal degradation than those utilizing untreated wheat straw samples. Equally important, it seems that the mechanical properties of the composites are not affected by the addition of silane treated samples in comparison with untreated wheat straw. In addition, another efficient treatment method is presented in this thesis. This method employs ultraviolet light to modify and improve the thermal stability of wheat straw. This method offers important economical and environmental benefits. Significant improvements (e.g., 40 ºC increase on the temperature at 2% of weight loss) were achieved after treatment for short periods of time (up to 15 minutes) and without the use of any pre-treatment or production of toxic by-products. This treatment method represents a novel application for ultraviolet light with potential for industrial use.

Le développement de structures de plus en plus légères et présentant des rapports performances/coût toujours plus élevés est un enjeu permanent dans le domaine des transports. Les matériaux polymères présentent des caractéristiques particulièrement bien adaptées à ces besoins. Ce travail de thèse repose sur le développement d’un matériau polymère destiné à être utilisé en tant que liner de réservoir de stockage d’oxygène liquide (LOX). L’objectif est de démontrer une réduction des masses de l’ordre de 20 à 30%, en comparaison avec des structures métalliques. Pour les besoins de l’application, le matériau à développer se doit de présenter une bonne compatibilité au LOX, une faible perméabilité aux gaz, des propriétés mécaniques suffisamment élevées à basse température ainsi qu’une bonne aptitude à la mise en forme par rotomoulage. La première partie de ces travaux a porté sur la compatibilité au LOX des polymères. En tenant compte des théories proposées dans la littérature, des nanocomposites à matrice polyamide 6 (PA6) ont été élaborés et caractérisés afin d’atteindre les performances recherchées. L’influence de différents paramètres supposés régir la tenue à l’oxygène liquide des matériaux polymères a ensuite été déterminée. Les nanocomposites obtenus présentent globalement une bonne compatibilité avec le LOX. Cette étude a également permis de mettre en évidence que les résultats sont fortement dépendants des paramètres liés à l’échantillonnage. Dans un second temps, la processabilité par rotomoulage de ces nanocomposites PA6 a été évaluée. Les propriétés rhéologiques et de stabilité thermique ont notamment été étudiées. Quelques essais de rotomoulage sur les systèmes les plus pertinents ont également été réalisés et ont démontré des résultats encourageants. Dans une dernière partie, les propriétés barrière aux gaz de ces systèmes PA6 ont été étudiées. Les perméabilités mesurées ont été interprétées en tenant compte de la morphologie des mélanges. En particulier, cette étude montre que les nanocomposites à base de PA6 et de graphite lamellaire présentent des performances adaptées pour l’application en raison de l’effet de tortuosité induit par la charge. Les propriétés mécaniques en traction uniaxiale des systèmes élaborés ont finalement été déterminées et confrontées aux spécifications requises. Les résultats obtenus montrent que les caractéristiques mécaniques sont tout à fait adaptées pour une utilisation en tant que liner de réservoir de stockage d’oxygène liquide. / In the field of transport, the development of lighter, cheaper and more efficient structures is a recurrent challenge. Polymer materials are good candidates for these applications due to their characteristics quite suitable for requirements. This Phd work aims at developing a thermoplastic material which will be used as an internal liner of a liquid oxygen (LOX) storage tank. The objective is to demonstrate a 20 % to 30 % weight saving, compared to metallic structures. To be used in this kind of application, the thermoplastic material must be LOX compatible, processable by rotational moulding and display a low gas permeability as well as good mechanical properties at low temperatures. In a first part, LOX compatibility of polymers was studied. Taking into account theories proposed in the literature, polyamide 6 (PA6) nanocomposites based on LCP, fluoride and graphite fillers were processed and characterized in order to reach desired properties. The influence of several parameters having an impact on LOX behaviour of polymers was then investigated. The nanocomposites show overall good compatibility with liquid oxygen. This study also demonstrates that LOX sensitivity largely depends on the preparation of samples. The processability of nanocomposites by rotational moulding has then been investigated. Rheological properties and thermal stability have especially been studied. Some rotational moulding trials were carried out on the most relevant systems and demonstrate promising results. Finally, the gas transport properties of PA6 nanocomposites were studied. Measured gas permeability was discussed as a function of the morphology of blends. In particular, this study shows that PA6 nanocomposites filled with lamellar graphite present convenient performances which are due to the tortuosity effect induced by the filler. Mechanical properties of filled systems were finally determined and compared with set requirements. The results show that mechanical characteristics are quite relevant for use as internal liner of LOX storage tank.

The main aim of this project was to investigate the possibility of manufacturing 3D parts of polyamide (nylon or PA) 6 by inkjetting its monomer caprolactam (CL). The principle of this process was similar to the other rapid prototype (RP) and rapid manufacturing (RM) processes in which a 3D part is manufactured by layer on layer deposition of material. PA6 was used as the thermoplastic polymer in this work because of its good properties and also because PA6 can be produced by heating its monomer (i.e. plus catalyst and activator) in a short time. Two polymerisation mixtures of CL-catalyst (mixture A) and CL-activator (mixture B) are intended to be jetted separately using conventional jetting heads and polymerise shortly after heating. Anionic polymerisation of CL (APCL) was investigated in the bulk and on a smaller scale. Sodium caprolactamate (CLNa and C10) and caprolactam magnesium bromide (CLMgBr) were used as catalysts and N-acetylcaprolactam (ACL) and a di-functional activator (C20) were used as activators. The influence of polymerisation conditions was investigated and optimised. These were catalyst-activator concentration, polymerisation temperature and the influence of the polymerisation atmosphere. The physical properties (monomer conversion, crystallinity, and viscosity average molecular weight) of PA6 samples produced using each catalyst-activator combinations were measured and compared. Small scale polymerisation was carried out using a hotplate, by hot stage microscopy and using differential scanning calorimetry (DSC). The influence of heating strategy on small scale polymerisation was studied using DSC. The polymerisation mixture compositions were characterised using rheometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and optical microscopy to investigate their suitability in jetting for using the available jetting heads. It was shown that the combination of CLMgBr-ACL resulted in fast polymerisation which was not sensitive to moisture. The C10-C20 combination resulted in fast polymerisation with the best properties in a protected environment (nitrogen); however, the polymerisation was affected by moisture in air and the properties of polymer produced and rate of polymerisation decreased in air. Polymers produced using CLNa-ACL had the poorest properties and polymerisation did not occur in air. Material characterisation showed that micro-crystals of CLMgBr existed in CLMgBr-CL mixture at the jetting temperature (80oC) which were too large to be jetted. However, the mixture of C10 in CL could be partially jetted. The activator mixtures had similar properties to CL and were easily jetted. Drop on drop polymerisation was carried out by dripping droplets of mixtures A and B (at 80oC) on top of each other on a hotplate at the polymerisation temperature. Small scale polymerisation in a DSC showed that the monomer conversion increased with increase in polymerisation temperature from 140oC to 180oC and decreased from 180oC to 200oC. The crystallinity of the polymer produced in the DSC decreased with increase in polymerisation temperature. Hot stage microscopy produced evidence for simultaneous polymerisation and crystallisation processes on heating. Small scale polymerisation in an oven and analysed by DSC showed that increasing catalystactivator concentration resulted in increasing monomer conversion and decrease in crystallinity. Monomer conversion also increased with increase in polymerisation temperature and polymerisation time. Comparison between small scale and bulk polymerisations shows a good agreement between the two polymerisation rates. This shows that the polymerisation mechanism did not change significantly when the quantity of materials was reduced to less than 20mg. Finally, the polymerisation was carried out in a DSC after jetting C10-CL and C20-CL mixtures into a DSC pan using a jetting system, which was made in another work.

A reciclagem de resíduos sólidos tem se tornado cada vez mais relevante devido a alguns fatores como os impactos ambientais ocasionados com o seu descarte inadequado, ao rigor crescente de legislação específica e ao custo elevado para o gerenciamento apropriado destes resíduos. Na área de materiais poliméricos, os resíduos poliméricos podem ser de origem pósconsumo ou pós-industrial. Alguns rejeitos industriais poliméricos possuem características estruturais ou químicas que impossibilitam o seu reaproveitamento direto no processo que o gerou, como é o caso filmes multicamadas de polietileno de baixa densidade (PEBD) com poliamida 6 (PA6), usados para a produção de embalagens. O presente trabalho teve como objetivo central o reaproveitamento de rejeitos de filmes multicamadas de PEBD com PA6 na forma de blendas recicladas destes polímeros, fazendo uso de agente compatibilizante e variação na composição das blendas com a incorporação de PA6 virgem, a fim de produzir materiais com propriedades adequadas e custo compatível para a aplicação comercial. O desenvolvimento experimental foi dividido em três etapas que consistiram na avaliação do teor mais adequado de agente compatibilizante de fases da blenda (etapa 1), na determinação do comportamento das propriedades das blendas não compatibilizadas em diferentes composições de rejeito do filme multicamada e PA6 virgem (etapa 2) e na associação do uso de compatibilizante com variação das composições das blendas (etapa 3). A partir da execução experimental das atividades das etapas 1 e 2 do trabalho foi possível determinar que o teor de 2,5% do agente compatibilizante polietileno grafitizado com anidrido maleico (PEg- AM) é o mais adequado para compatibilizar as blendas poliméricas e que a maioria das suas propriedades das blendas apresentam um comportamento próximo ao aditivo linear, que leva em consideração somente as propriedades iniciais dos componentes poliméricos PEBD e PA6 isolados. Os diversos materiais gerados no desenvolvimento desta pesquisa apresentam desempenho de propriedades e custo de produção variáveis em função do teor de PA6 nas blendas, que podem viabilizar o uso deste material reciclado em aplicações comerciais específicas. / Recycling of solid waste has been an important issue due to some factors such as environmental damage caused by inappropriate discards, increasing rigor of specific legislation and high cost to the appropriate management of these waste. Polymeric waste can be originated from post-consume or post-industrial sources. Some polymeric waste have chemical or structural characteristics that difficult their direct reuse in the same productive process such as multilayer film of low density polyethylene (LDPE) and polyamide 6 (PA6), which are used for packing. The aim of this work has been the study the mechanical recycling of multilayer films of PEBD and PA6 as PEBD/PA6 blends with adequate properties and compatible cost for commercial applications. The experimental development has been performed in 3 steps, which correspond to evaluation of more adequate content of compatibilizer agent for interface of blends (step 1), determination of behavior of the properties of blends without compatibilizer agent on different compositions of waste form multilayer films (step 2) and production of blends with compatibilizer agent graphitized polyethylene with maleic anhydride (PE-g-MA) (step 3). Has been verified that the content of 2.5% of PE-g-MA is more adequate to be used in the compatibilization of recycled PEBD/PA blends and that the performance of the blends dependents of the content of PA6 in the material. The recycled materials have potential for commercial applications.

Monitores de LCD (Liquid Crystal Display) para computador são equipamentos eletroeletrônicos que têm como destino de descarte os aterros sanitários ou a incineração. O vidro presente nas telas de LCD pode ser reaproveitado como carga em matrizes poliméricas para melhorar as propriedades mecânicas das mesmas ampliando o seu mercado de aplicação. A Poliamida-6 (PA-6) é um dos mais importantes plásticos de engenharia comercializados, devido as suas ótimas propriedades mecânicas e térmicas. Porém, a PA-6 é higroscópica e apresenta baixa estabilidade dimensional. A adição de cargas inorgânicas além de elevar o módulo de elasticidade do polímero, eleva a estabilidade dimensional devido à redução da absorção de água. Desse modo, compósitos de PA-6 reforçados com cargas particuladas provenientes de telas de LCD e microesferas de vidro, cargas usualmente empregadas pela indústria, foram processados em laboratório em extrusora dupla-rosca. Os corpos de prova foram obtidos por injeção e suas propriedades foram avaliadas por ensaio de resistência à tração, ensaio de resistência ao impacto Izod, com e sem entalhe, microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), análise termogravimétrica (TG) e difração de raios X (DRX). Os resultados indicaram que todas as cargas estudadas provocaram redução na resistência à tração da matriz de PA-6 e em sua resistência ao impacto, embora em alguns casos não tenham causado perdas significativas nos valores dos módulos de elasticidade. Embora as microesferas de vidro tenham mostrado desempenhos melhores quanto às propriedades mecânicas dos compósitos quando comparados àqueles que continham vidro particulado proveniente das telas de monitores LCD, o material reaproveitado apresenta potencial econômico e mecânico para ser usado como carga em matriz de PA-6, respeitadas as limitações mecânicas do compósito obtido. / The current destination of end of life (or defective) computer Liquid Crystal Displays (LCDs) is incineration or to be discarded in landfills. However, the inorganic glass of the LCDs can be used as a filler in polymer matrices. In particular, Polyamide-6 (PA-6) is one of the most important engineering polymers in the market, due to its remarkably good mechanical properties, although presenting high hygroscopicity and low thermal stability. The presence of an inorganic filler in PA-6s can elevate its elastic modulus, while improving its thermal stability. Therefore, in this study, several properties of PA-6 composites reinforced with LCDs particulate glass where compared to PA-6 composites reinforced with industrial glass spheres, a widespread industrial filler. Samples were prepared in a laboratory twin-screw extruder followed by injection molding, and were submitted to tensile strength test, Izod-notched impact resistance test, scanning electron microscopy, X-ray diffraction, and thermal analyses (TG and DSC). The results indicated that all studied fillers caused reduction in the tensile strength of the PA-6 matrix and in its impact strength, although, in some cases, did not cause any significant reduction in the values of the elastic modulus. Composites containing glass microspheres showed a better performance in terms of mechanical properties when compared to the ones containing particulate glass from LCD screens. Nevertheless, the recycled glass material exhibits mechanical and economic potential to be used as filler for PA-6 matrix, once the mechanical properties limitations of the obtained composites are adequately considered.

Spent oil based drilling fluid and cutting wastes are global liabilities due to their hazardous hydrocarbon content which impacts negatively on flora, fauna, and global carbon footprint. The formulation of two demulsifiers to ensure chemically enhanced phase separation of this waste into oil, water and solid components was successfully carried out in addition to recycling the solid phase into PA6 nanocomposite materials. Initial characterisation of the untreated waste was carried out by Fourier Transform Infra Red (FTIR) for total petroleum hydrocarbon (TPH) analysis, Inductively coupled plasma optical emission spectrometry (ICPOES) for quantitative elemental analysis and Energy dispersive xray analysis (EDXA) for qualitative elemental composition amongst other characterisation methods. The analysis showed that the sample had a high hydrocarbon load of 662,500mg/kg and a high heavy metal load for Pb of 122mg/kg. No As, Cd, Hg were detected. The demulsifier formulations were composed of isopropanol, sodium dodecyl sulphate, poloxamer, sodium chloride, chitosan in 0.2M acetic acid and deionised water for demulsifier S4 and addition of phosphoric acid for demulsifier S3. Hydrocarbon reduction on the extracted solid phase nanofiller S3 and nanofiller S4 was 98.6% and 98.5% respectively after demulsification. The demulsified spent oil based drilling fluid solid extracts were below OSPAR regulation of < 1% oil on cutting by weight. However, recycling of the recovered solid was carried out in order to achieve environmentally sustainable management of the waste in Polyamide 6 (PA6) nanocomposite manufacture/fabrication. The formulation of different blends of PA6 nanocomposite materials from untreated, demulsifier treated and thermally treated drilling fluid and cuttings was successfully achieved. Nanocomposite leaching test showed Pb immobilisation. The flexural and compressive - modulus and strength of the PA6 were markedly improved in the presence of the nanofillers and glass fibre. This was attributed to the reinforcement, exfoliating, stiffening, rigidity effect of the nanofillers. S6 (untreated drilling fluid) nanofillers significantly improved the mechanical properties of PA6. This was attributed to the increased interfacial bonding between the fillers and the polymer matrix as a result of the petroleum hydrocarbon present in the sample. The Thermogravemetric analysis (TGA) results showed that nanocomposites PA6/S3 and PA6/S3/GF30 had improved the thermal stability of PA6 by 13.6% and 38.8% respectively compared to PA6/S2 and PA6/S2/GF30 (simulated commercial nanocomposite materials) that improved PA6 by 9.7% and 35.8% respectively.

Monitores de LCD (Liquid Crystal Display) para computador são equipamentos eletroeletrônicos que têm como destino de descarte os aterros sanitários ou a incineração. O vidro presente nas telas de LCD pode ser reaproveitado como carga em matrizes poliméricas para melhorar as propriedades mecânicas das mesmas ampliando o seu mercado de aplicação. A Poliamida-6 (PA-6) é um dos mais importantes plásticos de engenharia comercializados, devido as suas ótimas propriedades mecânicas e térmicas. Porém, a PA-6 é higroscópica e apresenta baixa estabilidade dimensional. A adição de cargas inorgânicas além de elevar o módulo de elasticidade do polímero, eleva a estabilidade dimensional devido à redução da absorção de água. Desse modo, compósitos de PA-6 reforçados com cargas particuladas provenientes de telas de LCD e microesferas de vidro, cargas usualmente empregadas pela indústria, foram processados em laboratório em extrusora dupla-rosca. Os corpos de prova foram obtidos por injeção e suas propriedades foram avaliadas por ensaio de resistência à tração, ensaio de resistência ao impacto Izod, com e sem entalhe, microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), análise termogravimétrica (TG) e difração de raios X (DRX). Os resultados indicaram que todas as cargas estudadas provocaram redução na resistência à tração da matriz de PA-6 e em sua resistência ao impacto, embora em alguns casos não tenham causado perdas significativas nos valores dos módulos de elasticidade. Embora as microesferas de vidro tenham mostrado desempenhos melhores quanto às propriedades mecânicas dos compósitos quando comparados àqueles que continham vidro particulado proveniente das telas de monitores LCD, o material reaproveitado apresenta potencial econômico e mecânico para ser usado como carga em matriz de PA-6, respeitadas as limitações mecânicas do compósito obtido. / The current destination of end of life (or defective) computer Liquid Crystal Displays (LCDs) is incineration or to be discarded in landfills. However, the inorganic glass of the LCDs can be used as a filler in polymer matrices. In particular, Polyamide-6 (PA-6) is one of the most important engineering polymers in the market, due to its remarkably good mechanical properties, although presenting high hygroscopicity and low thermal stability. The presence of an inorganic filler in PA-6s can elevate its elastic modulus, while improving its thermal stability. Therefore, in this study, several properties of PA-6 composites reinforced with LCDs particulate glass where compared to PA-6 composites reinforced with industrial glass spheres, a widespread industrial filler. Samples were prepared in a laboratory twin-screw extruder followed by injection molding, and were submitted to tensile strength test, Izod-notched impact resistance test, scanning electron microscopy, X-ray diffraction, and thermal analyses (TG and DSC). The results indicated that all studied fillers caused reduction in the tensile strength of the PA-6 matrix and in its impact strength, although, in some cases, did not cause any significant reduction in the values of the elastic modulus. Composites containing glass microspheres showed a better performance in terms of mechanical properties when compared to the ones containing particulate glass from LCD screens. Nevertheless, the recycled glass material exhibits mechanical and economic potential to be used as filler for PA-6 matrix, once the mechanical properties limitations of the obtained composites are adequately considered.

The objective of this study is to process and characterize the compatibilized blends of acrylonitrile-butadiene-styrene (ABS) and polyamide-6 (PA6) using olefin based reactive copolymers and subsequently to utilize this blend as a matrix material in short glass fiber (SGF) reinforced composites and organoclay based nanocomposites by applying melt processing technique. In this context, commercially available epoxydized and maleated olefinic copolymers, ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) and ethylene-n butyl acrylate-carbon monoxide-maleic anhydride (EnBACO-MAH) were used as compatibilizers at different ratios. Compatibilizing performance of these two olefinic polymers was investigated through blend morphologies, thermal and mechanical properties as a function of blend composition and compatibilizer loading level. Incorporation of compatibilizer resulted in a fine morphology with reduced dispersed particle size. At 5 % EnBACO-MAH, the toughness was observed to be the highest among the blends produced. SGF reinforced ABS and ABS/PA6 blends were prepared with twin screw extrusion. The effects of SGF concentration and extrusion process conditions on the fiber length distribution, mechanical properties and morphologies of the composites were examined. The most compatible organosilane type was designated from interfacial tension and short beam flexural tests, to promote adhesion of SGF to both ABS and PA6. Increasing amount of PA6 in the polymer matrix improved the strength, stiffness and also toughness of the composites. Effects of compatibilizer content and ABS/PA6 ratio on the morphology and mechanical properties of 30% SGF reinforced ABS/PA6 blends were investigated. The most striking result of the study was the improvement in the impact strength of the SGF/ABS/PA6 composite with the additions of compatibilizer. Melt intercalation method was applied to produce ABS/PA6 blends based organoclay nanocomposites. The effects of process conditions and material parameters on the morphology of blends, dispersibility of nanoparticles and mechanical properties were investigated. To improve mixing, the screws of the extruder were modified. Processing with co-rotation yielded finer blend morphology than processing with counter-rotation. Clays were selectively exfoliated in PA6 phase and agglomerated at the interface of ABS/PA6. High level of exfoliation was obtained with increasing PA6 content and with screw speed in co-rotation mode. Screw modification improved the dispersion of clay platelets in the matrix.

The effects of melt state compounding and addition order of ethylene-butyl acrylate-maleic anhydride (E-BA-MAH), ethylene-glycidyl methacrylate (E-GMA), ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) terpolymer and/or three types of organoclays (Cloisite&reg / 15A, 25A and 30B) on morphology, thermal, mechanical and dynamic mechanical properties of polyamide-6 are investigated. XRD patterns show that the interlayer spacing for Cloisite&reg / 15A remained unchanged / however it increased for the organoclays Cloisite&reg / 25A and Cloisite&reg / 30B in both polyamide-6/organoclay binary nanocomposites and in polyamide-6/organoclay/impact modifier ternary systems. TEM analyses indicate that exfoliated-intercalated nanocomposites are formed. Sizes of elastomeric domains in nanocomposites are larger than the domains in their corresponding blends. The MFI results show that incorporation of elastomer reduces the MFI, due to the formation of graft copolymer. Both storage and loss moduli and complex viscosity of polyamide-6 increase with organoclay addition. In DMA measurements, in rubbery region, all nanocomposites show higher storage modulus than the unfilled counterparts. In general, the organoclays increase tensile and flexural strength, Young&amp / #8217 / s and flexural modulus and elongation at break, but decrease the impact strength, on the contrary, the addition of elastomer has the opposite effect. Generally, Cloisite&reg / 15A containing ternary nanocomposites have higher tensile, flexural and impact strength and Young&amp / #8217 / s and flexural modulus than the ternary nanocomposites prepared with Cloisite&reg / 25A and Cloisite&reg / 30B. In general, nanocomposites processed by adding all the ingredients simultaneously give higher tensile and flexural strength and modulus than the nanocomposites produced by other mixing sequences.