Made available in DSpace on 2014-12-17T14:07:18Z (GMT). No. of bitstreams: 1 LourdesARR_TESE.pdf: 12458480 bytes, checksum: 0efd4ff8bfb0c0bf6bcd3c18e449a690 (MD5) Previous issue date: 2013-05-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Nacomposites of polymers and lamellar clayminerals, has generated high scientific and technological interest, for having mechanical properties and gas barriers differentiated of polymers and conventional composites. In this work, it was developed nanocomposites by single screw extruder and injection, utilizing commercial raw material, with the goal to investigate the quality of new developed materials. It was evaluated the influence of the content and the kind of clay in the structure and in the nanocomposites properties. It was used regular and elastomeric poly (methyl methacrylate) (Acrigel LEP 100 and Acrigel ECP800) and six montmorillonites (Cloisite 10A, 11B, 15A, 20A, 25A e 30B) at the concentration of 1% e 3% in weight. The nanocomposites were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), colorimetric, optical transparency, flexural and tensile tests, Rockwell hardness and esclerometry. It was founded that is possible to obtain intercalated and exfoliated nanocomposites PMMA/MMT, and the top results was obtained in the materials with 1%in clay weight organophilizated with 2M2HT (Cloisite 15A and 20A) presented intercalate and hybrid morphology (exfoliated and flocullated). The ones that was produced with organophilizated clay with 2MHTL8 (Cloisite 30B) had excellent visual quality, but the majority presented hybrid morphology. In the materials processed with organophilizated clay with MT2ETOH (Cloisite 30B), there were color change and loss of transparency. It occurs improvement in a few mechanical properties, mainly in the materials produced with PMMA elastomeric (Acrigel ECP800), being more significant, the increase in the resistance to stripping in those nanocomposites / Nanocomp?sitos de pol?meros e argilominerais lamelares t?m gerado alto interesse cient?fico e tecnol?gico por possu?rem propriedades mec?nicas e de barreira ? g?s diferenciadas de pol?meros e de comp?sitos convencionais. Neste trabalho, foram desenvolvidos nanocomp?sitos por meio de extrusora monorosca e injetora, utilizando mat?rias-primas comerciais, com a finalidade de investigar a qualidade dos novos materiais desenvolvidos. Foi avaliada a influ?ncia do teor e do tipo de argila na estrutura e nas propriedades dos nanocomp?sitos. Foram usados PMMA comum e elastom?rico (Acrigel? LEP100 e Acrigel? ECP800) e seis argilas montmorilonitas (Cloisite? 10A, 11B, 15A, 20A, 25A e 30B) nas concentra??es de 1% e 3% em peso. Os nanocomp?sitos foram caracterizados por difra??o de raios X (DRX), termogravimetria (TGA), microscopia eletr?nica de transmiss?o (MET), colorimetria, transpar?ncia ?ptica, ensaios de tra??o uniaxial, flex?o, dureza Rockwell e esclerometria. Constatou-se que ? poss?vel obter nanocomp?sitos PMMA/MMT intercalados e esfoliados, sendo os melhores resultados obtidos nos materiais processados com 1% em peso de argilas organofilizadas com 2MBHT (Cloisite? 10A e 11B). Materiais produzidos com argilas organofilizadas com 2M2HT (Cloisite? 15A e 20A) apresentaram morfologia intercalada e h?brida (esfoliada e floculada). J? os produzidos com argilas organofilizadas com 2MHTL8 (Cloisite? 25A) tiveram excelente qualidade visual, por?m a maioria apresentou morfologia h?brida. Nos materiais processados com argilas organofilizadas com MT2ETOH (Cloisite? 30B) houve altera??o na cor e perda da transpar?ncia. Houve melhoria em algumas propriedades mec?nicas, principalmente nos materiais produzidos com PMMA elastom?rico (Acrigel? ECP800), sendo mais significativo, o aumento na resist?ncia ao riscamento nesses nanocomp?sitos

Orientadores: Ulf Friedrich Schuchardt, Wanda de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T22:38:59Z (GMT). No. of bitstreams: 1 Fabri_Fabio_M.pdf: 968913 bytes, checksum: b5ce9f5a7ed13272f76412a97e10bcc5 (MD5) Previous issue date: 2006 / Resumo: O complexo de samário(III), CpSm(DIPPh)Br, foi sintetizado a partir do brometo de samário(III) utilizando como ligantes o ânion ciclopentadienil (Cp) e o ânion b- dicetimínico 2-(2,6-diisopropilfenil)aminopent-2-en-4-(2,6-diisopropilfenil)imino, (DIPPh). O complexo foi caracterizado através de espectroscopia na região do visível, espectroscopia de emissão atômica por plasma indutivamente acoplado (ICP-AES) para determinação do metal e argentimetria para determinação do brometo. O complexo foi testado na polimerização de metacrilato de metila, a partir do sistema catalítico gerado com a adição de butil-lítio na razão molar butil-lítio/complexo = 2. Foram realizados ensaios para estudar a influência da razão monômero/catalisador, temperatura, bem como um estudo da dependência do tempo na polimerização. As condições ótimas de polimerização encontradas foram: temperatura de reação = 0°C; razão monômero/iniciador = 100 e tempo de reação de 1 h. Os polímeros foram caracterizados por ressonância magnética nuclear de H e C (RMN), espectroscopia na região do infravermelho (FT-IR), Cromatografia de permeação em gel (GPC), análise termogravimétrica (TGA) e calorimetria diferencial de varredura (DSC). Foram obtidas conversões de até 96 % e polímeros com massa molar (Mn) da ordem de 25000 g.mol, polidispersividade < 1,4. Finalmente, foi observado que um aumento da razão molar monômero:catalisador promove um aumento da estereosseletividade, produzindo polímeros com até 66 % de isotaticidade / Abstract: The samarium(III) complex, CpSm(DIPPh)Br, was synthesized from samarium(III) bromide using cyclopentadienyl (Cp) and 2-(2,6- diisopropylphenyl)aminopent-2-en-4-(2,6-diisopropylphenyl)imine, (DIPPh), as ligands. The complex was characterized by UV-vis spectroscopy, atomic emission spectroscopy by induced coupled plasma to determine the metal content and argentimetry to determine de bromide content. The complex was tested in the polymerization of methyl methacrylate using the catalytic system generated by addition of butyl lithium at a butyl lithium/complex molar ratio of two. Essays were carried out to investigate the influence of monomer/catalyst molar ratio, temperature, and time dependence of the polymerization. The best conditions found for the polymerization of methyl methacrylate were: temperature of reaction: 0°C; monomer/catalyst molar ratio: 100 and time of polymerization: 1 h. The polymers were characterized by H and C nuclear magnetic resonance (NMR), Fourier transformed infrared spectroscopy (FTIR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Conversions of up to 96 % and molar masses (Mn) in order of 25,000 g.mol were obtained, with molar mass distributions lower than 1.4. An increase of the monomer/catalyst molar ratio was observed to promote an increase of the stereoselectivity, producing polymers with isotacticity of 66 % / Mestrado / Quimica Inorganica / Mestre em Química

Orientadores: Ulf Friedrich Schuchardt, Wanda de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-06T03:56:11Z (GMT). No. of bitstreams: 1 Muterle_RobertoBineli_M.pdf: 1714020 bytes, checksum: 34cf02b750a6c26868dd7eecf4a508e8 (MD5) Previous issue date: 2006 / Resumo: Estudou-se a síntese do complexo de samário (III) com 2 ligantes 2-(2,6- diisopropilfenil)aminopent-2-en-4-(2,6-diisopropilfenil)imina [(2,6DIPPh)2nacnac]. A síntese do complexo foi conduzida em atmosfera inerte e THF como solvente através da adição de 2 equivalentes do ligante ionizado sobre o brometo de samário e subseqüente adição de 2 equivalentes de butil-lítio. O complexo foi caracterizado por ressonância magnética nuclear de H e C, espectroscopia na região do visível e espectroscopia de emissão atômica com plasma indutivamente acoplada, para determinar a quantidade de Sm e Li presentes no complexo e argentometria para determinação do Br. A atividade catalítica do complexo foi testada na polimerização do metacrilato de metila. Os testes catalíticos foram conduzidos em atmosfera inerte utilizando tolueno como solvente e variando condições reacionais como tempo, temperatura e razão catalisador/monômero. Observou-se que a ordem de adição dos reagentes durante a síntese do complexo é um fator decisivo para a atividade do catalisador e que as melhores condições de polimerização ocorreram à 0 °C, com uma razão monômero/catalisador de 90 durante 30 minutos de reação, gerando 90 % de rendimento em polímeros. Os produtos obtidos foram caracterizados por cromatografia de permeação em gel, análise termogravimétrica, espectroscopia na região do infravermelho, ressonância magnética nuclear de H e C e calorimetria diferencial de varredura. Os polímeros apresentaram massa molar (Mw) da ordem de 25 000 g mol com um baixa polidispersão (1,30), sendo pred) eominantemente isotático (55 %) e uma temperatura de transição vítrea (Tg) em torno de 60°C. / Abstract: The synthesis of the samarium complex with 2 ligands 2-(2,6- diisopropylphenil)aminopent-2-en-4(2,6-diisopropylphenil)imine [(2,6DIPPh)2nacnac] was studied. The synthesis was carried out under inert atmosphere, by the addition of 2 equivalents of the ionized ligand under the samarium bromide and then were added 2 equivalents of butil-lithium. The complex was characterized by nuclear magnetic resonance of H and C, visible spectroscopy, atomic emission spectroscopy with induced coupled plasma to determine the amount of Sm, Li present in the complex and Br was determinatéd by argentometry. The catalytic activity of the complex was studied through the polymerization of methyl methacrylaté. The catalytic tests were carried out under inert atmosphere using toluene as solvent and changing reaction conditions such as monomer : catalyst molar ratio, temperature and time dependence. It was observed that the order of addition is a important factor to determine the catalyst activity and that the best conditions to the polymerization reaction are monomer/catalyst molar ratio: 90, 30 minutes of reaction at 0 °C, giving polymers with 90 % of yield. The polymers were characterized by H and C nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis and differential scanning calorimetry (DSC). The polymers showed molar masses (MW) around 25 Kg mol with low polydispersivity (1.30), 55% isotactic with glass transition temperature around 60°C. / Mestrado / Quimica Inorganica / Mestre em Química

Ever since their discovery, Carbon nanotubes (CNTs) have been renowned to be potential candidates for a variety of applications. Nevertheless, the difficulties accompanied with their dispersion and poor solubility in various solvents have hindered CNTs potential applications. As a result, studies have been developed to address the dispersion problem. The solution is in modifying the surfaces of the nanotubes covalently or non-covalently with a desired dispersant. Various materials have been employed for this purpose out of which polymers are the most common. Non-covalent functionalization of CNTs via polymer wrapping represents an attractive method to obtain a stable and homogenous CNTs dispersion. This method is able to change the surface properties of the nanotubes without destroying their intrinsic structure and preserving their properties. This thesis explores and studies the surface modification and solublization of pristine single and multiwalled carbon nanotubes via a simple solution mixing technique through non-covalent interactions of CNTs with various anionic and cationic conjugated polyelectrolytes (CPEs). The work includes studying the interaction of various poly(phenylene ethynylene) electrolytes with MWCNTs and an imidazolium functionalized poly(3-hexylthiophene) with SWCNTs. Our work here focuses on the noncovalent modifications of carbon nanotubes using novel CPEs in order to use these resulting CPE/CNT complexes in various applications. Upon modifying the CNTs with the CPEs, the resulting CPE/CNT complex has been proven to be easily dispersed in various organic and aqueous solution with excellent homogeneity and stability for several months. This complex was then used as a nanofiller and was dispersed in another polymer matrix (poly(methyl methacrylate), PMMA). The PMMA/CPE/CNT composite materials were cast or electrospun depending on their desired application. The presence of the CPE modified CNTs in the polymer matrix has been proven to enhance the composites thermal, mechanical and electrical properties compared to pristine CNTs. Various spectroscopic and microscopic techniques such as UV-vis, fluorescence, TEM, AFM and SEM were used to study and characterize the CPE/CNT complexes. Also, TGA, DSC and DMA were used to study the thermal and mechanical properties of the composite materials. Our current work represents a fundamental study on the non-covalent interactions between CNTs and CPEs on one hand and gives a real life example on the CPE/CNT application in composite materials and electronics.

Sub-micron patterning is fundamental to the fabrication of numerous devices Traditional commercial manufacturing methods either lack the resolution needed to attain the appropriate size or are prohibitively expensive due to low throughput or the necessity of expensive equipment. Imprint lithography is a rapid, inexpensive alternative to making sub-micron features that can be tailored to work with a variety of materials. Imprint lithography, while traditionally used with pure polymers has been tailored to be used with nanoparticle-polymer hybrid films. This work has achieved high-fidelity pattern transfer onto polymer-nanoparticle hybrid films with feature sizes as small as 250 nm. The polymer-nanoparticle hybrid was fabricated by creating a liquid suspension of functionalized ZnO nanoparticles and poly(methyl methacrylate) (PMMA) in a solvent. The ZnO particles were functionalized by adding nonanoic acid in order to facilitate the dispersion of the particles in a non-polar solvent. This suspension was spread onto substrate, imprinted with a patterned stamp, allowed to dry, and was demolded. The final result was features ranging from 250 nm to 1 μm in size with good fidelity as determined by the accuracy of the feature replication and the surface roughness of the overall sample. The effect of the ZnO content as well as the method of combining the suspension components on the feature fidelity was studied. In general, it was found that feature fidelity is acceptable up to a dry-film composition of 15 vol% ZnO and that feature sizes above 500 nm were more tolerant of higher solids loading. The same imprint lithography method was also used to pattern a polymer-derived SiOC glass. The SiOC was shown to be have interesting shrinkage properties where the feature-level linear shrinkage was up to 5% more than that of the bulk. The features were shown to be stable during pyrolysis up to 1000°C and stable at operating temperatures up to 1000°C. A constant number Monte Carlo simulation was used to describe the suspension behavior to confirm the empirical results from the physical experiments. The effects of Van der Waals forces, steric stabilization, depletion flocculation, as well as the physical impediment of entangled polymer chains were considered. A similar agglomeration behavior was shown in the simulations compared to the physical experiments. This thesis shows that polymer-nanoparticle hybrid films are a compatible material for imprint lithography using appropriate suspension parameters. This is very important for a variety of applications and devices. Using imprint lithography to make these devices makes them cheaper and more accessible to the commercial market and can make a large number of theoretical devices a reality. / Ph. D. / Sub-micron patterning is an integral part of making many modern technologies such as memory storage devices or integrated circuits. As this technology becomes smaller and smaller, the limiting factor for making these devices has become the ability to manufacture effectively at the appropriate scale. Traditional commercial manufacturing methods lack the resolution needed to attain small enough features. Manufacturing methods that can make small enough features are often either extremely expensive or offer incomplete control of the feature morphology. Imprint lithography is a high-throughput, inexpensive alternative to making sub-micron features that can be tailored to work with a variety of materials. Imprint lithography is simple process in which a patterned stamp is pressed into a softened film of material in order to transfer the pattern of the stamp onto that material. Traditionally, imprint lithography works best with polymers and researchers have struggled to pattern nanoparticle-based materials. This work has achieved high-fidelity pattern transfer onto polymer-nanoparticle hybrid films with feature sizes on the same order as the polymer films found reported in literature. The polymer-nanoparticle hybrid was realized by creating a liquid suspension of functionalized ZnO nanoparticles and poly(methyl methacrylate) (PMMA) in a solvent. The ZnO particles were functionalized by adding nonanoic acid, allowing the normally polar particles to disperse in the non-polar solvent needed to dissolve the PMMA. This suspension was spread onto a glass substrate, imprinted with a patterned stamp, allowed to dry, and was demolded. The final result was the successful transfer of features ranging from 250 nm to 1 μm in size with good fidelity. The effect of the ZnO content as well as the method of combining the suspension components on the feature fidelity was studied. To help prove the broad applicability of this imprint method, it was adapted for use with polymer-derived ceramics. Additionally, a computer simulation was developed to help understand the behavior of the nanoparticle-polymer suspension during the imprint process.

Ce manuscrit rassemble les recherches effectuées dans le cadre du développement d’une résine thermoplastique photopolymérisable pour une application composite. Ce travail a été effectué dans le cadre du projet COMPOFAST, lancé par ARKEMA à la fin de l’année 2012. Ce projet, accompagné par l’ADEME, a pour but, la mise au point d’une nouvelle génération de composites thermoplastiques à haute cadence de production pour la conception de pièces pour l’automobile. L’intérêt de ces matériaux, et donc du projet, est l’allégement des véhicules par réduction de la masse des pièces utilisées et la recyclabilité des matrices choisies. A travers ce projet, plusieurs techniques ont été envisagées. Dans le cadre de cette thèse c’est le procédé QCM, pour Quick Composite Molding, qui a été étudié au sein du LPIM. L’utilisation de la lumière pour assurer la polymérisation de la matrice rend novateur ce procédé. Cette étape dite de photopolymérisation est connue pour être l’un des moyens les plus rapides pour former une résine solide à partir d’une formulation liquide. Le procédé repose également sur la dépose automatisée de bandes de préimprégnés sur un moule ouvert afin d’augmenter la vitesse de production des pièces de composites. Techniquement, deux étapes ont été prévues : la première consiste en la réalisation des bandes de préimprégnés de manière automatique. La deuxième étape est la conception du composite par dépose automatique sur un moule des bandes de renforts préirradiés à laquelle succède une étape finale d’irradiation pour obtenir le composite requis. / This manuscript brings together research in the development of a light-curing thermoplastic resin for a composite application. This work was performed under the COMPOFAST project launched by Arkema at the end of 2012. This project, along with the ADEME, aims at the development of a new generation of thermoplastic composites with high production rates for designing automobile parts. The advantages of these materials, and therefore of the project, is making vehicles lighter by reducing the mass of the parts used and the recyclability of the selected matrices. Through this project, several techniques were considered. As part of this thesis, it's the QCM method for Quick Composite Molding, which has been studied within the LPIM. The use of light to ensure the polymerization of the matrix makes this method innovative. This step called photopolymerization is known to be one of the fastest ways to form a solid resin from a liquid formulation. The method also relies on the automated removal prepreg bands on an open mold in order to increase the rate of production of composite parts. Technically, two stages were planned: the first involves the automatically construction of prepreg tapes. The second step is the design of the composite by automatically depositing prepregs on the mold which is followed by a final step of irradiation to give the desired photocomposite.

An experimental and modelling investigation of a tetrafunctional initiator designed for free radical polymerizations is presented. Multifunctional initiators are believed to provide two advantages over traditional monofunctional initiators. With a higher number of functional sites per molecule, they are able to increase polymer production while simultaneously maintaining or increasing polymer molecular weight. Examination of the literature indicates the majority of academic and industrial published studies have investigated difunctional initiators with most focusing on styrene. In this thesis, a tetrafunctional initiator, JWEB50, was systematically investigated for a variety of monomer systems in order to develop a better understanding of the behaviour of multifunctional initiators in free radical polymerizations. <br /><br /> A kinetic study comparing the tetrafunctional initiator to a monofunctional counterpart, TBEC, demonstrated that the impact of a multifunctional initiator is dependent upon monomer type. Regardless of the homo- or copolymer system examined, it was observed that the tetrafunctional initiator could produce higher rates of polymerization due to the greater number of labile groups per initiator molecule. However, the influence of the tetrafunctional initiator on the polymer molecular weight was dictated by the polymerization characteristics of the system in question. In the case of styrene, the tetrafunctional initiator maintained similar molecular weights compared to the monofunctional initiator while for methyl methacrylate (MMA), switching from a mono- to a tetrafunctional initiator actually decreased the polymer molecular weight. Other monomers such as butyl acrylate and vinyl acetate and copolymers of MMA and styrene or alpha-methyl styrene were examined to study the effect of initiator functionality in free radical polymerizations. <br /><br /> Subsequent to the kinetic investigation, polystyrene and poly(methyl methacrylate) samples produced with the tetrafunctional initiator were characterized in detail in order to examine the effects of initiator functionality on polymer properties. Samples generated with the monofunctional initiator were used for comparison purposes. Chromatographic and dilute solution methods were able to detect significant levels of branching in the polystyrene sample produced with JWEB50, while poly(methyl methacrylate) samples showed no evidence of branching. Rheological tests involving a combination of oscillatory and creep shear measurements were completed in order to detect differences between samples. The presence of branching using rheological techniques was clearly observed for both polystyrene and poly(methyl methacrylate) samples produced with the tetrafunctional initiator. <br /><br /> In order to explain the experimental results observed in the kinetic and polymer properties studies, a reaction mechanism for polymerizations initiated with a tetrafunctional initiator was proposed and used in the development of a mathematical model. Reactions involving the fate/efficiency of functional groups are properly accounted for, while in the past this had been ignored by modelling work in the literature. Based on model predictions, di-radical concentrations were estimated to be several orders of magnitude smaller than mono-radical concentrations and their contribution in the reaction mechanism was found to be negligible. Modelling results also demonstrated that the concentration and chain length of various polymer structures (i. e. , linear, star or coupled stars) depend upon monomer type and reaction conditions.

An experimental and modelling investigation of a tetrafunctional initiator designed for free radical polymerizations is presented. Multifunctional initiators are believed to provide two advantages over traditional monofunctional initiators. With a higher number of functional sites per molecule, they are able to increase polymer production while simultaneously maintaining or increasing polymer molecular weight. Examination of the literature indicates the majority of academic and industrial published studies have investigated difunctional initiators with most focusing on styrene. In this thesis, a tetrafunctional initiator, JWEB50, was systematically investigated for a variety of monomer systems in order to develop a better understanding of the behaviour of multifunctional initiators in free radical polymerizations. <br /><br /> A kinetic study comparing the tetrafunctional initiator to a monofunctional counterpart, TBEC, demonstrated that the impact of a multifunctional initiator is dependent upon monomer type. Regardless of the homo- or copolymer system examined, it was observed that the tetrafunctional initiator could produce higher rates of polymerization due to the greater number of labile groups per initiator molecule. However, the influence of the tetrafunctional initiator on the polymer molecular weight was dictated by the polymerization characteristics of the system in question. In the case of styrene, the tetrafunctional initiator maintained similar molecular weights compared to the monofunctional initiator while for methyl methacrylate (MMA), switching from a mono- to a tetrafunctional initiator actually decreased the polymer molecular weight. Other monomers such as butyl acrylate and vinyl acetate and copolymers of MMA and styrene or alpha-methyl styrene were examined to study the effect of initiator functionality in free radical polymerizations. <br /><br /> Subsequent to the kinetic investigation, polystyrene and poly(methyl methacrylate) samples produced with the tetrafunctional initiator were characterized in detail in order to examine the effects of initiator functionality on polymer properties. Samples generated with the monofunctional initiator were used for comparison purposes. Chromatographic and dilute solution methods were able to detect significant levels of branching in the polystyrene sample produced with JWEB50, while poly(methyl methacrylate) samples showed no evidence of branching. Rheological tests involving a combination of oscillatory and creep shear measurements were completed in order to detect differences between samples. The presence of branching using rheological techniques was clearly observed for both polystyrene and poly(methyl methacrylate) samples produced with the tetrafunctional initiator. <br /><br /> In order to explain the experimental results observed in the kinetic and polymer properties studies, a reaction mechanism for polymerizations initiated with a tetrafunctional initiator was proposed and used in the development of a mathematical model. Reactions involving the fate/efficiency of functional groups are properly accounted for, while in the past this had been ignored by modelling work in the literature. Based on model predictions, di-radical concentrations were estimated to be several orders of magnitude smaller than mono-radical concentrations and their contribution in the reaction mechanism was found to be negligible. Modelling results also demonstrated that the concentration and chain length of various polymer structures (i. e. , linear, star or coupled stars) depend upon monomer type and reaction conditions.

Apatite was formed on the surface of titanium dioxide (TiO2) powders by a biomimetic process. The deposition was accomplished by immersing TiO2 powders in simulated body fluid (SBF) for 1, 3, 6, 12, and 24 h. SBF used throughout this study had calcium and phosphate ion concentrations 10 times greater than those of human blood plasma. Photocatalytic activity of the apatite-deposited TiO2 powders was investigated in terms of the decomposition of methylene blue solution under ultraviolet (UV) irradiation. It has been shown that apatite deposition enhanced the photocatalytic activity of TiO2. The best photocatalytic performance was acquired on the powders that are immersed in SBF for 3 h. The time required for the complete degradation of methylene blue decreased from 3.5 h to 2 h upon immersion of powders in SBF for 3 h. Photochemical durability of poly(methyl methacrylate) increased when it was mixed with apatite-deposited TiO2 powders.

The design, fabrication, and characterization of polymer-carbon nanotube (CNT) composites have generated a significant amount of attention in the fields of materials science and polymer chemistry. The challenge in fabricating composites that exploit the unique properties of the CNT and the ideal processing ability and low cost of the polymer is in achieving a uniform dispersion of the filler in the polymer matrix. This body of work focuses on (1) techniques employed to disperse CNTs into a polymer matrix and (2) the effects of CNTs on the mechanical and electrical properties of the polymer. Poly (methyl methacrylate) (PMMA), an amorphous polymer, and poly (4-methyl-1-pentene) (P4M1P), a semi crystalline polymer, were chosen as the matrices. Non-functionalized single-walled carbon nanotubes and soot (unpurified carbon nanotubes) were chosen as the filler material. In the first study, single-walled carbon nanotubes (SWNTs) were sonicated in methyl methacrylate monomer and initiated via thermal energy, UV light, and gamma radiation. Composite films with increased dielectric constants and unique optical transparency were produced. Samples were characterized using differential scanning calorimetry, dielectric analysis, and dynamic mechanical analysis. Refractive Indices were obtained and correlated to the dielectric constant using Maxwells relationship. PMMA/soot composites were fabricated in the second study. Dispersion was accomplished by way of sonication and melt compounding. The PMMA/soot composites were exposed to gamma radiation, with a 137Cs gamma source, in order to investigate how the filler affects the polymers ability to resist radiation. Samples were characterized by differential scanning calorimetry, dielectric analysis, and dynamic mechanical.