Phenylindane monomers 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane (DAPI), 5,6-diamino-1-(4-aminophenyl)-1,3,3-trimethylindane (TAPI) and 6-hydroxy-1-(4-hydroxyphenyl)-1,3,3-trimethylindane (DHPI) were synthesized and characterized. DAPI, as well as other diamines, were then utilized in solution step polycondensation with a number of commercially available dianhydrides using either the two-step ester-acid solution imidization or the high temperature solution imidization routes. High molecular weight soluble fully cyclized polyimides were successfully synthesized using a 1:1 molar ratio of dianhydride to diamine. The polyimides were film forming and were characterized by size exclusion chromatography (SEC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and selective gas permeation methods, as well as other techniques. The O2 permeation and O2/N2 selectivity values obtained for materials prepared in this thesis are discussed in relation to the concept of an "upper bound", as defined in the literature concerning gas separation membranes. The series of polyimides based on DAPI and several dianhydrides were found to have high glass transition temperatures (247°C-368°C) and very good short-term thermal stability as shown by TGA, despite the partially aliphatic character of DAPI. The 5,5'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bis-1,3-isobenzenefurandione (6FDA)/DAPI system also exhibited low weight loss under nitrogen at 400°C, which was comparable to that of a wholly aromatic polyimide based on 1,2,4,5-benzenetetracarboxylic dianhydride (PMDA)/4,4'-oxydianiline (ODA) which is known to have high thermal stability. In addition, the 6FDA/DAPI polyimides had a refractive index value of 1.571 from which the dielectric constant was calculated, giving an attractively low estimated value of 2.47. The rigid, bulky and isomeric structure of DAPI in the repeat unit imparted film forming characteristics that allowed production of solvent cast membranes which displayed a range of O2 permeability and O2/N2 selectivity characteristics. High O2 permeabilities were observed for polyimides in which the DAPI structure predominated in relation to the overall polymer repeat unit, i.e. in combination with low molar mass dianhydrides. The more flexible dianhydrides afforded a greater degree of molecular freedom and were thought to result in a more tightly packed polymer conformation which decreased the rate of gas penetration through thin films. The DAPI/3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) system showed the best combination of O2 permeability and O2/N2 selectivity values (2.8Ba and 7.3, respectively). Modest variations in the DAPI isomeric ratio did not significantly effect the gas permselectivity properties. High molecular weight polyimides based on DAPI and BTDA were synthesized by three different routes. The ester-acid and thermal imidization methods produced polyimides with the highest Tgs and best thermal stability in air, as compared to the chemical imidization procedure. For example, a Tg increase of 22°C and a 68°C increase in the 5% weight loss were found for the ester-acid imidized DAPI/BTDA polyimide over those found for the chemically imidized version. The higher Tg and 5% weight loss values were attributed to the elimination of residual uncyclized amide acid moieties. Polyimides derived from 6FDA were synthesized by the high temperature solution imidization method. Thin films, cast from NMP, were tough and creasable and afforded high Tg (>295°C) systems with good thermal stability. When combined with rigid diamines, 6FDA contributed to high O2 permeation and moderate O2/N2 selectivity. The high O2 permeability was ascribed to hindered interchain packing attributed to the bulky CF3 groups. The exceptionally high oxygen permeability and O2/N2 selectivity values of the 9,9-bis(4-aminophenyl) fluorene (FDA)/6FDA system, were near the desirable "upper bound" for gas separation membrane materials, while those of 3,7-diamino-2,8-dimethyl-dibenzothiophene-5,5-dioxide (DDBT)/6FDA were actually above the upper bound. High performance polymers based on 4,4'-bis [4-(3,4-dicarboxyphenoxy)]biphenyl dianhydride (BPEDA), 2,2'-bis [4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride (BPADA), 2,2-bis(3-amino-4-methylphenyl)hexafluoroisopropylidene dianhydride (Bis-AT-AF) and 3,7-diamino-2,8-dimethyl-dibenxothiophene-5,5-dioxide (DDBT) were also synthesized in this work. Additionally, they were characterized with regard to molecular weight, glass transition temperature, and thermal stability. Polyimide systems containing hydroxyl moieties in the repeat unit were also investigated. Incorporation of hydroxyl moieties in the repeat unit enhanced chain stiffness via intermolecular hydrogen bonding and showed Tg increases of ~30°C Hydroxyl moieties also decreased the thermal stability values typically observed for polyimides. High O2/N2 selectivity was achieved with all of the 4,4'-diaminobiphenyl-3,3'-diol (HAB) containing polymers. However, these materials also had low O2 permeabilities, which suggested a tightly packed structure, possibly facilitated by hydrogen bonding. In contrast to suggestions in the literature, the comparison between a polyimide having pendant hydroxyl groups and another having the same repeat unit without them did not reveal a significant change in permselectivity behavior. The synthesis, characterization and crosslinking behavior of functional polyimides containing phenol, amine and acetylene moieties are also described. A crosslinking reaction of oligomers containing phenol moieties with a tetrafunctional epoxy resin was achieved 100°C below the "dry" glass transition temperature and was attributed to residual solvent. Utilization of this crosslinking mechanism could allow membrane optimization by investigating the influence of a number of variables, such as the concentration of the phenolic moiety, epoxy weight percent, catalyst concentration and residual solvent content. / Ph. D.

Methods for the large scale preparation and purification of bis( 4-aminopheny 1)-1- phenyl-2,2,2-trifluoroethane (3F-diamine) and bis( 4-hydroxyphenyl)-1-phenyl-2,2,2- trifluoroethane (3F bis-phenol) have been developed. Spectroscopic characterization of by-products was used to develop a mechanistic understanding for synthetic design and to formulate purification techniques needed to produce monomer grade products. Utilizing the preparative methods represented in the present work, it was possible to obtain sufficiently pure 3F-diamine to allow the synthesis of soluble, end-capped, fully cyclized polyimides with glass transition temperatures greater than 430°C. The direct preparation of 3F bis-phenol from phenol and trifluoroacetophenone by trifluoromethanesulfonic acid catalyzed hydroxy alkylation was optimized to produce monomer grade 3F bisphenol. Previously reported methods were less direct and produced lower purity product. Current research efforts are exploring the utility of this monomer system for the preparation of novel poly(arylene ethers), polycarbonates, and polyesters. Bis(4-hydroxy-3- aminophenyI)-1-phenyl-2,2,2-trifluoroethane [3F-bis(aminophenol)] has recently been successfully prepared from 3F-phenol. Soluble, high glass transition temperature, fully-cyclized polybenzoxazoles have been obtained from 3F-bis(aminophenol). The synthesis and characterization of polymer systems containing the phosphine oxide unit as an integral part of the backbone continue to be areas of active research. To date the majority of research activity has centered on the synthesis and features of poly(arylene ether phosphine oxide) (PEPO). All PEPOs gave significant amounts of phosphorus-containing char at temperatures where other engineering polymers are completely volatilized. This behavior was related to the superior self-extinguishing behavior of all the phosphorus containing systems. A detailed pyrolytic degradation study of the phosphorus containing PEPO system was carried out. The study utilized analytical techniques such as pyrolysis-gas chromatography-mass spectroscopy and neutron activation analysis. To continue the exploration of the phosphine oxide systems, the synthesis and characterization of a novel phosphorus containing diamine, bis( 4-amino-phenyl) phenylphosphine oxide, has been completed. Further research is in progress preparing phosphine oxide based polyimides from this diamine. Synthesis of bis(4-hydroxyphenyl)phenylphosphine oxide and additional phosphine oxide intermediates are also reported. / Ph. D.

This thesis has focused on the synthesis and characterization of amino functional monomers, principally monomers containing aryl phosphine oxide units. Utilization of these monomers was demonstrated in various types of linear and network polymerizations. The diamines monomers included bis(3-aminophenyl) methyl phosphine oxide (DAMPO), bis(3-aminophenyl) phenyl phosphine oxide (DAPPO), bis(3-aminophenoxy phenyl) phenyl phosphine oxide (BAPPO) and bis(3-aminophenoxy phenyl) methyl Phosphine oxide (BAMPO). From these monomers high molecular weight poly(ether imides), polyurea-urethanes, poly(arylene ether ketones) poly(arylene ether sulfones) and poly(arylene ether phosphine oxides) were. Internal and external fire testing methodologies showed that the new polymers containing phosphine oxide units were fire resistant while maintaining the desirable physical characteristics of carefully selected control systems. In addition, suitable curing schedules for epoxy networks were determined by using dielectric monitoring techniques. The curing rates varied with the structure of the monomers and were slowest for the deactivated control (4,4'aminophenyl sulfone). Epoxy networks containing aryl phosphine oxide units had higher char yields in dynamic thermogravimetric analyses than control specimens. This correlated with their superior flame resistance. The brittle epoxy matrices were subsequently modified with reactive or non-reactive thermoplastic polymers in order to improve their fracture toughness. Poly(ether imides) and poly(ether sulfones) showed good phase separation behavior with tetrafunctional epoxy matrices during the curing reactions, as confirmed by scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). Mechanical tests showed that reactive thermoplastic modification of the epoxy networks improved the fracture toughness of the systems, without noticeable decreases in other characteristics such as flexural modulus. Reactive systems also maintained chemical resistance in contrast to non-reactive thermoplastic controls. / Ph. D.

A series of random and amorphous copolyesters containing different cycloaliphatic rings within the polymer chains were prepared by melt polycondensaton of difunctional monomers (diesters and diols) in the presence of a catalyst. These polyesters were characterized by nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile tests and/or dynamic mechanical analysis (DMA). The copolyester based on dimethyl bicyclo[2.2.2]octane-1,4-dicarboxylate (DMCD-2) was observed to have a higher Tg, about 115ºC, than the other copolyesters with the same compositions in this study. For copolyesters containing different compositions of dimethyl-1,4-cyclohexane dicarboxylate (DMCD) and DMCD-2, the Tg increased linearly with the increase of DMCD-2 mole content. DMA showed that all of the cycloaliphatic copolyesters had secondary relaxations, resulting from conformational transitions of the cyclohexylene rings. The polyester based on DMCD-3 in the hydrolytic tests underwent the fastest hydrolytic degradation among these samples. A new triptycene diol (TD) was synthesized and incorporated into a series of cycloaliphatic copolyester backbones by melt condensation polymerization. Straight chain aliphatic spacers, including ethylene glycol (EG), 1,4-butanediol (BD) and 1,6-hexanediol (HD), were used as co-diols to explore their effects on polyester properties. An analogous series of non-triptycene copolyesters based on various hydroxyethylated bisphenols were also prepared for comparison. The results revealed that the TD-containing polymers had higher thermal stability and higher Tg's than the corresponding non-TD analogs. For TD-containing copolyesters, the mechanical properties were found to be dependent on the types and compositions of the co-diols. A 1,4-butanediol-based triptycene copolyester was observed to have a significantly increased Tg and modulus while maintaining high elongation at ambient temperature. Furthermore, it was demonstrated that the triptycene polyester exhibited higher Tg and modulus than those containing bisphenol derivatives. However, all of the 1,4-butanediol based copolyesters were brittle and had comparable moduli at low temperatures (-25°C or -40 °C). Melt polycondensation was also used to prepare a series of all-aliphatic block and random copolyesters including the following aliphatic monomers: trans-DMCD, DMCD-2, neopentyl glycol (NPG), diethylene glycol (DEG) and dimethyl succinate (DMS). The polymer compositions were determined by 1H NMR, and the molecular weights were determined using SEC. The polyesters were also characterized by TGA, DSC, DMA and tensile tests. Phase separation was not observed in these block copolyesters. However, the block copolyester containing DMCD-2 and NPG was observed to have a higher Tg than the block copolyester based on trans-DMCD and NPG. In addition, these block copolyesters were found to have better mechanical properties than the corresponding random copolyesters. / Ph. D.

No description available.

O objetivo deste estudo foi avaliar a influência de dois aditivos, propionaldehyde (propanal aldeído) e 2,3-butanedione (diquetona diacetil), nas propriedades de comonômeros, copolímeros e resinas compostas à base de Bis-GMA, quando diluído com TEGDMA, Bis-GMA propoxilado (CH3Bis-GMA) e Bis-GMA propoxilado fluorinado (CF3Bis-GMA). Comonômeros, copolímeros e compósitos experimentais foram preparados combinando Bis-GMA com TEGDMA, CH3Bis-GMA, CF3Bis-GMA e, aldeído (24 e/ou 32 mol%) e diquetona (24 e/ou 32 mol%). No caso dos compósitos, partículas híbridas silanizadas (bário aluminosilicato; 60 peso%) foram adicionadas aos comonômeros. Para a fotopolimerização, adicionou-se canforoquinona (0,2 peso%) e N,N-dimetil-p-toluidina (0,2 peso%). Os comonômeros e copolímeros experimentais tiveram as seguintes propriedades avaliadas: viscosidade, contração de polimerização, grau de conversão, ângulo de contato (em esmalte, dentina e vidro), temperatura de transição vítrea (DSC e equação de Fox), microdureza, alteração de rugosidade superficial e desgaste por abrasão. Os compósitos experimentais, tiveram avaliadas as seguintes propriedades: resistência flexural, módulo de elasticidade, tração diametral, módulo de resiliência, microdureza, alteração de rugosidade superficial e desgaste por abrasão. Os sistemas Bis-GMA/TEGDMA e Bis-GMA/CH3Bis-GMA tiveram suas propriedades significantemente alteradas pela incorporação de aditivos (propanal ou diquetona). Os aditivos (propanal/diquetona) não influenciaram de forma significante as propriedades do sistema Bis-GMA/CF3Bis-GMA. O efeito dos aditivos nas propriedades dos materiais analisados relaciona-se à sua abilidade em aumentar o grau de conversão de alguns sistemas resinosos / The purpose of this study was to evaluate the effect of two additives, propionaldehyde (aldehyde) and 2,3-butanedione (diketone), on the properties of Bis-GMA based comonomer, copolymer and composites when diluted with TEGDMA, propoxylated Bis- GMA (CH3Bis-GMA) and propoxylated fluorinated Bis-GMA (CF3Bis-GMA). Experimental comonomer/copolymer/composites were prepared combining Bis-GMA and TEGDMA, CH3Bis-GMA, CF3Bis-GMA, with aldehyde (24 and/or 32 mol%) and diketone (24 and/or 32 mol%). For composites, hybrid treated filler (barium aluminosilicate glass; 60 wt%) was added to monomer mixtures. Photopolymerization was effected by using camphorquinone (0.2 wt%) and N,N-dimethyl-p-toluidine (0.2 wt%). Experimental comonomer/copolymers viscosity, polymerization shrinkage, degree of conversion, contact angle (enamel, dentin and glass surfaces), glass transition temperature (DSC and Fox equation), microhardness, surface roughness changes and wear were evaluated. Experimental composites, flexural strength, modulus of elasticity, diametral tensile strength, modulus of resilience, microhardness, surface roughness changes and wear were also assessed. Bis-GMA/TEGDMA and Bis- GMA/CH3Bis-GMA systems had properties significantly influenced by incorporation of additives (either propanal or diketone). Additives (propanal/diketone) did not significantly influence on Bis-GMA/CF3Bis-GMA system properties. The effect of additives on the evaluated material properties is mainly attributed to their ability in improving some resin systems degree of conversion

An introduction is given to the background theory and scientific literature of the major subject areas of interest in this thesis, namely the chemistry of free radical and anionic polymerisation, molecular weight control in each type of polymerisation, polymerisation reactors, computer simulation of polymerisation processes and polymer characterisation by gel permeation chromatography. A novel computer model has been devised, based on the analysis of the polymerisation process in terms of the reaction extent of each reactant and the use of generation functions to describe the concentration of living and dead polymeric species, for the free radical, solution polymerisation of methylmethacrylate in a CSTR. Both heat and mass balance expressions have been described. Conversion, Mn and Mw were monitored. To test the model a reactor was designed and constructed. A detailed description of the reactor and the experimental conditions used for the validation of the model are given. The results of these studies are presented and excellent agreement is shown between model predictions and experiments up to 30% conversion for Mn w and % conversion. A similar study is described for the anionic polymerisation of styrene in tetrahydrofuran as solvent, in a CSTR. In this work the computer model becomes 'stiff' when realistic rate constants are introduced in the kinetic expressions. Experimental difficulties were encountered in obtaining reproducible results in the anionic work. A new approach of using 'scavengers' as protecting agents for the living chains is described. A scavenger was successfully employed in the preparation of block copolymers using a tubular reactor. Block copolymerisation, in addition to providing a means of checking the number of the 'living' chains inside the reactor, is of interest in its own right. All the experimental findings are discussed in relation to the currently accepted views found in the scientific literature.

Two new monomers / 2-benzyl-5,12-dihydro-2Hpyrrolo[ 3&rsquo / ,4&rsquo / :2,3][1,4]dioxocino[6,7-b]quinoxaline (DPOQ) and 5,12- dihydrothieno[3&rsquo / ,4&rsquo / :2,3][1,4]dithiocino[6,7-b]quinoxaline (DTTQ), were synthesized. The chemical structures of the monomers were characterized by Nuclear Magnetic Resonance (1H-NMR), Fourier Transform Infrared (FTIR) and Mass Spectrometry (MS). Copolymer of DPOQ with bithiophene (BT) was synthesized via potentiostatic electrochemical polymerization in acetonitrile (ACN)-tetrabutylammonium tetrafluoroborate (TBAFB) solvent-electrolyte couple. For DTTQ, copolymerization with bithiophene was achieved via potentiodynamic method in dichloromethane (DCM)-tetrabutylammonium hexafluorophosphate (TBAFP) solvent-electrolyte couple. Characterizations of the resulting copolymers were performed by cyclic voltammetry (CV), FTIR, Scanning Electron Microscopy (SEM) and UV-Vis Spectroscopy. Four-probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the copolymer films were investigated. In addition, dual type polymer electrochromic devices (ECDs) based on P(DPOQ-co-BT) and P(DTTQ-co-BT) with poly(3,4- ethylenedioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts and optical memories.

O objetivo deste estudo foi avaliar a influência de dois aditivos, propionaldehyde (propanal aldeído) e 2,3-butanedione (diquetona diacetil), nas propriedades de comonômeros, copolímeros e resinas compostas à base de Bis-GMA, quando diluído com TEGDMA, Bis-GMA propoxilado (CH3Bis-GMA) e Bis-GMA propoxilado fluorinado (CF3Bis-GMA). Comonômeros, copolímeros e compósitos experimentais foram preparados combinando Bis-GMA com TEGDMA, CH3Bis-GMA, CF3Bis-GMA e, aldeído (24 e/ou 32 mol%) e diquetona (24 e/ou 32 mol%). No caso dos compósitos, partículas híbridas silanizadas (bário aluminosilicato; 60 peso%) foram adicionadas aos comonômeros. Para a fotopolimerização, adicionou-se canforoquinona (0,2 peso%) e N,N-dimetil-p-toluidina (0,2 peso%). Os comonômeros e copolímeros experimentais tiveram as seguintes propriedades avaliadas: viscosidade, contração de polimerização, grau de conversão, ângulo de contato (em esmalte, dentina e vidro), temperatura de transição vítrea (DSC e equação de Fox), microdureza, alteração de rugosidade superficial e desgaste por abrasão. Os compósitos experimentais, tiveram avaliadas as seguintes propriedades: resistência flexural, módulo de elasticidade, tração diametral, módulo de resiliência, microdureza, alteração de rugosidade superficial e desgaste por abrasão. Os sistemas Bis-GMA/TEGDMA e Bis-GMA/CH3Bis-GMA tiveram suas propriedades significantemente alteradas pela incorporação de aditivos (propanal ou diquetona). Os aditivos (propanal/diquetona) não influenciaram de forma significante as propriedades do sistema Bis-GMA/CF3Bis-GMA. O efeito dos aditivos nas propriedades dos materiais analisados relaciona-se à sua abilidade em aumentar o grau de conversão de alguns sistemas resinosos / The purpose of this study was to evaluate the effect of two additives, propionaldehyde (aldehyde) and 2,3-butanedione (diketone), on the properties of Bis-GMA based comonomer, copolymer and composites when diluted with TEGDMA, propoxylated Bis- GMA (CH3Bis-GMA) and propoxylated fluorinated Bis-GMA (CF3Bis-GMA). Experimental comonomer/copolymer/composites were prepared combining Bis-GMA and TEGDMA, CH3Bis-GMA, CF3Bis-GMA, with aldehyde (24 and/or 32 mol%) and diketone (24 and/or 32 mol%). For composites, hybrid treated filler (barium aluminosilicate glass; 60 wt%) was added to monomer mixtures. Photopolymerization was effected by using camphorquinone (0.2 wt%) and N,N-dimethyl-p-toluidine (0.2 wt%). Experimental comonomer/copolymers viscosity, polymerization shrinkage, degree of conversion, contact angle (enamel, dentin and glass surfaces), glass transition temperature (DSC and Fox equation), microhardness, surface roughness changes and wear were evaluated. Experimental composites, flexural strength, modulus of elasticity, diametral tensile strength, modulus of resilience, microhardness, surface roughness changes and wear were also assessed. Bis-GMA/TEGDMA and Bis- GMA/CH3Bis-GMA systems had properties significantly influenced by incorporation of additives (either propanal or diketone). Additives (propanal/diketone) did not significantly influence on Bis-GMA/CF3Bis-GMA system properties. The effect of additives on the evaluated material properties is mainly attributed to their ability in improving some resin systems degree of conversion

Résumé confidentiel / Résumé confidentiel