Devido à preocupação com o meio ambiente e o volume crescente de resíduos plástico em aterros sanitários, os polímeros biodegradáveis estão sendo estudados extensivamente. Um deles é o PLA. Apesar de possuir propriedades comparáveis a polímeros commodities e polímeros de engenharia, ainda é necessário melhorar certas características do PLA, como resistência ao impacto. Para isso, a nanocelulose (NC) pode ser usada sem alterações significativas na biodegradação polimérica. Este estudo teve como objetivo obter a nanocelulose, caracteriza-la e incorpora-la ao poli(ácido láctico) (PLA), assim como, estudar as propriedades térmicas, morfológicas e mecânicas do compósito obtido. A NC foi obtida por hidrólise ácida utilizando ácido fosfórico e posteriormente foi silanizada com três silanos distintos. As nanopartículas foram caracterizadas por Birrefringência, Microscopia Eletrônica de Transmissão (MET), Termogravimetria (TG), Potencial Zeta, Espectroscopia Vibracional de Absorção no Infravermelho com Transformada de Fourier (FTIR) e Difração de Raio X (DRX). Com as imagens obtidas pelo MET foi possível medir o tamanho das partículas de NC. E então obter a razão de aspecto de 82 e o limite de percolação de 1,1% em massa, confirmando a morfologia de nanofibra. De acordo as analises TG\'s, a presença de NC silanizada aumentou o início da degradação térmica. Os compósitos, contendo 3% em massa de NC, foram obtidos por fusão em câmara de mistura e moldados por injeção. Os compósitos foram caracterizados por FTIR, Cromatografia de Permeação em Gel (GPC), TG, Calorimetria Exploratória Diferencial (DSC), Microscopia Eletrônica de Varredura (MEV-FEG), Impacto e Tração. As análises dos compósitos mostraram que a NC atuou como agente de nucleação, facilitando a cristalização do PLA, além de a NC ter atuado como reforço na matriz polimérica melhorando as propriedades mecânicas. / Due to concern for the environment and the growing volume of plastic waste in landfills, biodegradable polymers are being studied extensively. One of them is the PLA. Despite properties comparable to commodities polymers and engineering polymers, it is still necessary to improve certain characteristics of PLA, such as impact resistance. For this, the nanocelulose (CN) can be used without significant changes on the polymeric biodegradation. This study aimed to obtain nanocelulose, characterizes it and incorporates it to polylactic acid (PLA), even as, studies of thermal, morphological and mechanical properties of the composites processed. The CN was obtained by acid hydrolysis using phosphoric acid and it was, subsequently, silanized with three different silanes. The nanoparticles were characterized by Birefringence, Transmission Electron Microscopy (TEM), Thermogravimetry (TG), Zeta Potential, Spectroscopy Absorption Vibrational Infrared Fourier Transform (FTIR) and X-Ray Diffraction (XRD). By images taken by TEM was possible to measure the size of particles CN. So, obtain the aspect ratio of 82 and the percolation limit of 1.1 wt%, demonstrating morphology of nanofiber. According to TG analysis, the beginning of thermal degradation increased when CN Pure was compared with modified CN. The composite, containing 3 wt% CN, were obtained by melt in mixing chamber and then injection molded. The composites were characterized by FTIR, Gel Permeation Chromatography (GPC), TG, Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Impact and Tensile Strength. The results showed that the CN acts as a nucleating agent in PLA, facilitating the crystallization and acts as reinforcement in polymer matrix to improve the mechanical properties.

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As the miniaturization of functional devices in integrated circuit (IC) continues to scale down to sub-nanometer size, the process complexity increases and makes materials characterization difficult. One of our research effort demonstrates the development and application of novel Multiple Internal Reflection Infrared Spectroscopy (MIR-IR) as a sensitive (sub-5 nm) metrology tool to provide precise chemical bonding information that can effectively guide through the development of more efficient process control. In this work, we investigated the chemical bonding structure of thin fluorocarbon polymer films deposited on low-k dielectric nanostructures, using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Complemented by functional group specific chemical derivatization reactions, fluorocarbon film was established to contain fluorinated alkenes and carbonyl moieties embedded in a highly cross-linked, branched fluorocarbon structure and a model bonding structure was proposed for the first time. In addition, plasma induced damage to high aspect ratio trench low-k structures especially on the trench sidewalls was evaluated both qualitatively and quantitatively. Damage from different plasma processing was correlated with Si-OH formation and breakage of Si-CH3 bonds with increase in C=O functionality. In another endeavor, TiN hard mask defect formation after fluorocarbon plasma etch was characterized and investigated. Finding suggest the presence of water soluble amines that could possibly trigger the formation of TiN surface defect. An effective post etch treatment (PET) methods were applied for etch residue defect removal/suppression.

This diploma thesis deals with the study of isothermal crystallization of nanocomposite materials based on isotactic polypropylene (iPP) and nanosilica, depending on the volume fraction (0, 2, 4 and 6 %) and type of silica and the crystallization temperature. Fumed silica and four types of silica with different surface treatment were used as filler. The crystallization performed at temperatures 136, 138, 140 and 142 °C has been studied in-situ using polarized optical microscope and the crystallization rate was evaluated from the growing radius of spherulites. It can be stated that particles of silica have been inbuilt into the spherulites due to the linear growth of spherulites of all composite materials. The most significant increase of the crystallization rate of iPP was caused by fumed silica, the most significant decrease was caused by silica TS-720 at volume fraction 4 %. The crystallization rate (G) has been slightly increased with the increasing volume fraction of filler at 136 °C, the G slightly decreased at 138 °C and there was no trend of G for two higher temperatures. Also, it was not possible to exactly evaluate the influence of the surface treatments. The reason is the most probably uneven (non-homogenous) distribution of nanosilica as revealed thermogravimetric analysis. The crystallization kinetics was evaluated according to the Lauritzen-Hoffmann theory. The morphological part of the study showed that iPP was in ? and ß-structure and spherulites of ? phase were of the type I, II and mixed.

The present work deals with the electrical properties of nanocomposite materials. Samples for the experiment are made of epoxy resin as a matrix and oxides TiO2, Al2O3, WO3, SiO2 as nanofillers in 0.5 and 1 percent performance. The experimental samples are measured in temperature and frequency dependence of relative permittivity, dissipation factor, rezistivity and are broken down by the influence of filler on the electrical properties of the polymer. Attention is also paid to the mechanical properties of nanocomposites.

The present master´s thesis deals with the electrical properties of nanocomposite materials. Samples for the experiment are made epoxi resin and oxides TiO2 and Al2O3 as nanofillers in different percent performace. The samples nanocomposites are measured temperature dependence of the resistivity inside, dissipation factor and relative permittivity. It discusses the effect of the filler on the resulting electrical properties of the polymer.

Polymerní biomateriály jsou jedním ze současných populárních témat vzhledem k možnosti potenciální aplikace v tkáňovém inženýrství a řízeného dávkování léčiv v organismech. Kolagen je jako jeden z nejčastěji se vyskytujících proteinů zvláště zajímavý díky svým rozmanitým vlastnostem bez imunoreakce organismu příjemce. Tato práce je zaměřena na samouspořádávací procesy, kinetiku, obecné zákonitosti řídící proces samouspořádání a mechanické vlastnosti kolagenních roztoků. Dále je zkoumán efekt hydroxyapatitových nanočástic na samouspořádávání kolagenu a mechanické vlastnosti výsledných nanokompozitních hydrogelů. Jsou objasněny možné mechanismy interakcí mezi kolagenem I a hydroxyapatitem spolu s popisem vývoje struktury a vlastností na různých úrovních struktury. Byly měřeny a molekulárně interpretovány závislosti viskoelastických veličin na smykové rychlosti spolu s viskoelastickým chováním. Dále byla studována struktura kolagenních scaffoldů a určen vliv HAP a síťování. Závěrem byly diskutovány výsledky v souvislosti s jejich aplikovatelností v tkáňovém inženýrství chrupavek tvrdých tkání a v regenerativní medicíně.

The work deals mainly with preparation protocol of nanocomposites. The task of this work is to study structural and procedural parameteres that control the dispersion of nanoparticles in polymer solution to be able to prepare desired spatial organization of nanoparticles. The work resolves the effect of various components such as polymer matrices, nanoparticles and solvent, in which matrices and nanoparticles are blended. Used components control final dispersion state of nanoparticles and it influences also properties of investigated materials such as glass transition temperature, stiffness and rheological properties.

Dans cette étude, nous avons cherché à développer de nouvelles formulations pour améliorer la stabilité thermique et le comportement au feu de trois matrices polymères de grande diffusion: le polyéthylène (PE), le polystyrène (PS) et le polyamide 66 (PA66). Le système intumescent employé consiste à combiner des retardateurs de flammes classiques (polyphosphate d’ammonium (APP) et pentaérythritol (PER)) avec une faible quantité de nanooxydes métalliques dont les propriétés auraient été ajustées sur mesure de façon à améliorer la compatibilité du mélange à l’état fondu, ou encore pour changer le mécanisme de dégradation d’un point de vue chimique (effets catalytiques) ou physiques (effet barrière, viscosité etc…). Une partie importante de cette étude a donc été d’abord consacrée à la synthèse d’oxydes à morphologie, porosité, structure ou fonctionnalités particulières. A cet égard, les silices mésoporeuses possèdent l’avantage de présenter des surfaces spécifiques élevées (700-1400 m²/g) et une taille de pores compatible avec les chaines polymères. En adaptant les conditions de synthèse, nous avons cherché à établir des relations entre certains paramètres relatifs aux silices préparées (tels que la (1) surface spécifique (2) la taille des particules (3) la taille des pores (4) la morphologie et (5) le type de structure (en général SBA-15)) sur la stabilité thermique et le comportement au feu du polyéthylène. Préalablement, les propriétés texturales, structurales et chimiques de ces silices ont été caractérisées par porosimétrie à l’azote à 77K, DRX et FTIR. Globalement, les améliorations apportées par les silices mésostructurées restent modestes par rapport à celles induites par les RF classiques seuls et ceci particulièrement pour les polymères non charbonnants (PE et PS). Ceci est dû probablement à la très grande disparité des teneurs respectives en silice et RF dans les composites testés (1 et 24% en masse, respectivement). L’effet du taux de silice SBA-15 (0,5-10wt%) à taux de charge constant et égal à 25% massique a été également étudié pour les trois matrices polymères. Les valeurs maximales d’IOL (indice limite d’oxygène) sont toujours obtenues pour 1-2% de SBA-15. Les modifications de surface des silices SBA-15 par greffage des différentes fonctions organiques (CTAB, amine, thiol, phénol, phosphonate, acide benzoïque et diphénylphosphate), inorganiques (aluminium, acide phosphorique et acide tungstophosphorique) ou métalliques (cuivre, nickel) ont fait l’objet de caractérisations poussées afin d’évaluer la quantité et la stabilité thermique des espèces greffées ainsi que la nature des liaisons de surface. D’autres types de nanooxydes synthétiques (aluminophosphates, phosphate de zirconium et nanotubes de type titanates) ou commerciaux (CeO2, ZrO2, CeZr et CePr) ont également été étudiés. La plupart de ces échantillons a montré un effet légèrement positif sur la stabilité thermique et le comportement au feu des polymères. De point de vue mécanistique, les analyses réalisées en Py-GC-MS montrent que les oxydes greffés par des acides catalysent la transformation des alcènes et des diènes issus de la décomposition du PE en aromatiques. En présence de SBA-15, l’analyse des résidus carbonés (par DRX, FTIR) montrent la formation de nouvelles phases cristallines phosphosiliciques qui renforcent la couche protectrice. Les phases condensées et gazeuses de quelques formulations performantes en IOL ont été analysée par cône calorimètre et microcalorimètre (PCFC). La substitution d'une fraction d'APP/PER par de la silice SBA-15 a un effet plus marqué sur la stabilité thermique et le comportement au feu de la matrice PA66 (IOL= 48,5 (+10 par rapport au PA66/APP/PER), comparé aux matrices PE (IOL=25 (+0,5 par rapport au PE/APP/PER) et PS (IOL= 24,1 (+0,8 par rapport au PS/APP/PER). De plus, la fonctionnalisation [...] / In this study, we have tried to develop new formulations to improve the thermal stability and fire behavior of three polymer matrices widely used: the polyethylene (PE), the polystyrene (PS) and the polyamide 66 (PA 66). The intumescent system used consists to combine a classical flame retardants (ammonium polyphosphate (APP) and pentaeryhthritol (PER)) with a small amount of nanooxides whose properties can be adjusted in order to improve the compatibility of the melting mixture, or to change the degradation mechanism by a chemical (catalytic effect) or physical (insulating layer, viscosity, etc …) process. The total amount of additives has been set at 25wt%. An important part of this study was consecrated to the synthesis of oxides with different morphologies, porosities, structures and functionalities. In this regard, the mesoporous silica has an advantage of having a high surface area (700-1400 m²/g) and a pore size compatible with the polymer chains. By adapting the synthesis conditions, we have aimed to correlate between some parameters related to the prepared silicas (such as (1) the specific surface area (2) particle size (3) pore size (4) morphology and (5) the type of structure (usually SBA-15)) on the thermal stability and fire behavior of different polymer matrices. A comprehensive study has been conducted globally, regardless of the matrix, that the improvements provided by the mesostructured silicas are modest compared to those elicited by classical FR. However, the fire behavior has been improved (particularly LOI) by combining APP/PER system with 1-2wt% of SBA-15. The surface modification of SBA-15 by grafting a different organic functions (CTAB, amine, thiol, phenol, phosphonate, benzoic acid and diphenylphosphate), inorganic species (aluminum, phosphoric acid and tungstophosphoric acid) or metals (copper, nickel) have been the subject of an advanced characterizations in order to assess the amount and the thermal stability of the grafted species, well as the nature of the surface bonds. Other types of synthetic nanooxides (aluminophosphates, zirconium phosphate and titanate nanotubes) or commercial (CeO2, ZrO2, CeZr and CePr) have been also studied. Most of these particles in combination with APP/PER system have shown a slightly positive effect on the thermal stability and fire behavior of polymers. In mechanistic terms, the nanooxides have mainly an effect on enhancing the barrier effect. The analyses carried out by Py/GC/MS showed that the grafted oxides by acidic species catalyze the conversion of alkenes and dienes (resulting from the decomposition of PE) to aromatics. In the presence of SBA-15, the analysis of char (by XRD and FTIR) shows the formation of new crystalline phases which enhance the protective layer.

Polypropylene (PP) has excellent mechanical and chemical properties. Thus, it is used in a wide range of applications. However, like for most polymers, the high flammability of PP limits its application in various fields requiring specific flame-retardant standards. Some of halogenated flame retardants are restricted by European Community directives ROHs, WEEE and REACH. Now metallic hydroxides flame retardants are widely used in industry, but the high loading (about 60 wt %) seriously destroys the mechanical properties of polymeric materials. To improve the performance of flame retardant polymers, an environment-friendly electron beam (EB) technology has been successfully used in modifying flame retardant and polymer matrix. In this work, high efficient functional intumescent flame retardants and functional surfactant are designed and prepared for EB technology. In-depth studies the thermal stability, fire behavior and mechanical properties of these flame retardant PP composites have been studied. The possible graft-linking and cross-linking mechanisms of such EB modified composites can be well established. Specially, it is shown that the novel surfactant has better thermal stability in comparison to traditionally used modifiers. Another part of this work deals with the exploration of novel allylamine polyphosphate (AAPP) as flame retardant crosslinker for PP by electron beam (EB) treatment. Multifunctional AAPP showed unique efficient intumescent flame retardant properties. The limiting oxygen index (LOI) value and the effective melt drop resistance in UL-94 test of multifunctional flame retardant PP composites is greatly enhanced. In the cone calorimeter test, a reduction of peak heat release rate, total heat release and smoke production is achieved. Moreover, EB treatment increased the thermal stability of these designed flame retardant PP composites. Furthermore, AAPP provided an excellent quality of char residue in the combustion stage due to P−N−C and P−O−C structure. In addition, synergistic mechanism of AAPP with montmorillonite (MMT) was explored. Finally, different EB parameters have been used to modify fire retardant polymer nanocomposites. The effects of EB treatment on thermal stability, fire behavior and mechanical properties of fire retardant PP nanocomposites have been discussed. The heat release, the production of toxic gases and the mass loss of EB modified fire retardant PP nanocomposites are delayed in accordance to the result of cone calorimeter test. Based on these results high performance fire retardant polymer nanocomposites can be developed for industrial applications such as insulated material of wire, cable, etc.