No description available.

Genom ringöppningssampolymerisation av utvalda epoxider och anhydrider möjliggjordes en enkel strategi för att syntetisera funktionella sampolymerer. Sampolymererna hade förmågan att bilda tvärbundna material, och var dessutom benägna för både hydrolytisk och enzymatisk nedbrytning. Användning av organokatalysatorn PPNCl gjorde det möjligt att bilda sampolymerer genom alternerande ringöppning av epoxider och anhydrider. Utbytet var högt, och polymererna nådde molekylvikter i intervallet 0,7–7,6 kg mol-1. De omättade bindningarna i sampolymerernas sidokedjor gav dem förmågan att bilda tvärbundna nätverk. Graden av tvärbindning dikterades av sampolymerernas molekylära struktur och molekylvikt. De termiska egenskaperna hos sampolymererna reglerades genom att variera anhydriden, där strukturella skillnader mellan de valda anhydriderna hade en inverkan Tg och T5%. Tvärbindningsreaktionen resulterade i en ökning av både Tg och T5% i förhållande till de ursprungliga linjära sampolymererna. De klyvbara estergrupperna i sampolymerkedjorna gjorde det möjligt för sampolymererna att genomgå både hydrolytisk och enzymatisk nedbrytning. De nedbrutna sampolymererna påvisade en förändring i molekylvikt och dispersitet, samt en ökad viktminskning. De nedbrutna tvärbundna materialen visade på större svällning och lägre gelinnehåll än de initiala värdena före nedbrytning. Dessa resultat ger en ökad förståelse kring hur strukturen hos epoxid/anhydrid-baserade sampolyestrar påverkar deras egenskaper, så som förmågan att bilda tvärbundna material samt deras nedbrytbarhet. Förhoppningen är att denna studie ska gynna utvecklingen av nya material inom denna klass av polyestrar, och vara till hjälp för att förutse deras potentiella tillämpningar. / The ring-opening copolymerization of selected epoxides and anhydrides enabled a simple strategy to synthesize functional copolymers with the ability to form crosslinked materials and prone to hydrolytic and enzymatic degradation pathways. The synthesis utilized PPNCl as an organocatalyst and allowed the formation of copolymer chains by alternating ring-opening of epoxides and anhydrides in high yield and molar mass in the range of 0.7-7.6 kg mol-1. The pendant unsaturated bonds in the copolymer chains endowed the copolymers with the ability to form crosslinking networks. The degree of crosslinking was dictated by the molecular structure and molar mass of the copolymers. The thermal properties of the copolymers were regulated by varying the anhydrides, the difference in the structure of each anhydride influence the Tg and T5%. Crosslinking reaction indeed increased the Tg and T5% from the native copolymers. The presence of ester as cleavable groups in the copolymer chains allowed the copolymers to undergo hydrolytic and enzymatic degradation. The degraded copolymers showed a change in molar mass and dispersity and increased mass loss. The degraded crosslinked materials showed higher swelling ratio and lower gel content than the initial values before degradation. These results deliver a better understanding of the structure-property relationships, the ability to form crosslinked materials, and the degradation behavior of epoxides/anhydrides-based copolyesters. They should favor the design of new materials belonging to this class of polyesters and to envisage their potential applications.

No description available.

No description available.

High molecular weight star-shaped polystyrenes were prepared via the coupling of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) terminated polystyrene oligomers with divinylbenzene (DVB) in m-xylene at 138 °C. Linear polystyrene oligomers (Mn = 19,300 g/mol, Mw/Mn = 1.10) were synthesized in bulk styrene using benzoyl peroxide in the presence of TEMPO at approximately 130 °C. In situ mid-infrared spectroscopy was successfully utilized to follow initiation, monomer conversion, and polymer formation. Real-time data allowed for the determination of apparent rate constants of 2.1E-5 s⁻¹ at 132 °C and 1.2E-5 s⁻¹ at 126 °C from the profile of the decaying styrene vinyl carbon-hydrogen (=CH₂) absorbance at 907 cm⁻¹. Coupling of the TEMPO terminated oligomers under optimum conditions resulted in a compact and dense product with a number average molecular weight exceeding 300,000 g/mol (Mw/Mn = 3.03) after 24 h, suggesting the formation of relatively well-defined star-shaped polymers. Synthetic factors that affected the molecular weight, yield, and composition of maleic anhydride (MAH), norbornene (Nb), and tert-butyl 5-norbornene-2-carboxylate (NbTBE) terpolymers were investigated. Pseudo first order kinetic analysis using in situ FTIR indicated that the observed rate of reaction was a strong function of the Nb/NbTBE ratio with a maximum of 6.7E-5 s⁻¹ for a 50/0/50 Nb/NbTBE/MAH monomer ratio and a minimum of 1.1E-5 s⁻¹ for a 0/50/50 Nb/NbTBE/MAH ratio. Polymer yields were also observed to be a function of the Nb/NbTBE ratio and also decreased with increasing NbTBE. Calculated work of adhesion values (Wadh) values were observed to increase as the content of NbTBE was increased. 193 nm photoresist formulations incorporating polymers with high NbTBE content showed increased imaging performance using 193 nm light and successfully produced sharp and defined features as small as 110 nm, which was demonstrated via scanning electron microscopy (SEM). Additional functionality was introduced via the copolymerization of MAH with several norbornene (Nb) derivatives that were synthesized from facile Diels-Alder cycloaddition reactions of cyclopentadiene with a-olefins containing electron withdrawing groups. Subsequent hydrolysis of the anhydride offered further versatility and provided an avenue to introduce aqueous base solubility into Nb/MAH copolymers. / Ph. D.

A designed series of directly copolymerized homo- and disulfonated copolymers containing controlled degrees of pendant sulfonic acid groups have been synthesized via nucleophilic step polymerization. Novel sulfonated poly (arylene ether sulfone) copolymers using 4,4'-bisphenol A, 4,4'-biphenol, hexafluorinated (6F) bisphenol AF, and hydroquinone, respectively, with dichlorodiphenyl sulfone (DCDPS) and 3,3'-disodiumsulfonyl-4,4'-dichlorodiphenylsulfone (SDCDPS) were investigated. Molar ratios of DCDPS and SDCDPS were systematically varied to produce copolymers of controlled compositions, which contained up to 70 mol% of disulfonic acid moiety. The goal is to identify thermally, hydrolytically, and oxidatively stable high molecular weight, film-forming, ductile ion conducting copolymers, which had properties desirable for proton exchange membranes (PEM) in fuel cells. Commercially available bisphenols were selected to produce cost effective alternative PEMs. Partially aliphatic bisphenol A and hexafluorinated (6F) bisphenol AF produced amorphous copolymers with different thermal oxidative and surface properties. Biphenol and hydroquinone was utilized to produce wholly aromatic copolymers. The sulfonated copolymers were prepared in the sodium-salt form and converted to the acid moiety via two different methodologies and subsequently investigated as proton exchange membranes for fuel cells. Hydrophilicity increased with the level of disulfonation, as expected. Moreover, water sorption increased with increasing mole percent incorporation of SDCDPS. The copolymers' water uptake was a function of both bisphenol structure and degree of disulfonation. Furthermore, the acidification procedures were shown to influence the Tg values, water uptake, and conductivity of the copolymers. Atomic force microscopy (AFM) in the tapping mode confirmed that the morphology of the copolymers could be designed to display nanophase separation in the hydrophobic and hydrophilic (sulfonated) regions. Morphology with either co-continuous hydrophobic or hydrophilic domains could be attained for all the sulfonated copolymers. The degree of disulfonation required for continuity of the hydrophilic phase varied with biphenol structure. Proton conductivity values for the sulfonated copolymers, under fully hydrated conditions, were a function of bisphenol and degree of sulfonation. However, at equivalent ion exchange capacities the proton conductivities were comparable. A careful balance of copolymer composition and acidification method was necessary to afford a morphology that produced ductile films, which were also sufficiently proton conductive. The copolymers of optimum design produced values of 0.1 S/cm or higher, which were comparable to the commercial polyperfluorosulfonic acid material Nafion™ control. / Ph. D.

Novel, highly functional rod-like copolymers have been synthesized by alternating copolymerization of N, N, Nâ , Nâ -tetraalkyl-4, 4â -diaminostilbenes (TDAS) with maleic anhydride. Dynamic light scattering, 2H solid state NMR and persistence length measurement reveal high chain rigidity of the polymer backbone. Double quantum heteronuclear local field solid state NMR spectroscopy (2Q-HLF Solid State NMR) has been employed to investigate the chain structure of ¹³C labelled copolymer. The torsional angle of the H-13C-13C-H part of the anhydride ring was zero degrees, indicating an all cis configuration of the H-13C-13C-H moiety of the anhydride ring. Rod-coil block copolymers containing rigid polyampholyte blocks were designed and synthesized by addition-fragmentation chain transfer (RAFT) copolymerization. The rigid polyampholytes blocks were formed by hydrolysis of alternating copolymers and the flexible coil block consists of poly(oligo(ethylene glycol) methacrylate). The rod-coil block copolymers form polyion complex (PIC) aggregates even when the polyampholyte blocks are charge imbalanced. The aggregates did not dissociate upon the addition of high concentrations of NaCl unlike the dissociation of flexible polyampholytes in NaCl solution. These unique solution properties are induced by 'like-charge attractions' of the rigid polyampholytic alternating copolymer chains. An example, of what is birefringent to be a novel class of material, has been prepared which enables the control of the birefringence of a polymer film by controlling the rotation of aromatic groups pendant to the polymer backbone. A linear rigid bisphenol monomer, 4,4′-dihydroxyterphenyl (DHTP), has been incorporated into poly(aryl ether sulfone)s (PAES) in a study to impart crystallization to these amorphous polymers. Three bisphenols, 4, 4′-isopropylidenediphenol, 4, 4′-(hexafluoroisopropylidene)diphenol and 4,4′-dihydroxybiphenyl have been copolymerized with DHTP and dichlorodiphenylsulfone. Only the segmented polysulfone containing 50% BP and 50% DHTP was semi-crystalline. This PAES had a melting temperature (Tm) 320°C in the first heating cycle of a DSC measurement and the presence of crystallites was confirmed by wide angle X-ray diffraction (WAXS). / Ph. D.

No description available.

Cross-linked poly(ethylene oxide) (XLPEO) based on poly(ethylene glycol) diacrylate (PEGDA) is an amorphous rubbery material with potential applications for carbon dioxide removal from mixtures with light gases such as methane, hydrogen, oxygen and nitrogen. Changing the polymer network structure of XLPEO through copolymerization has previously been shown to influence gas transport properties, which correlated with fractional free volume according to the Cohen-Turnbull model. This project explores strategic modifications of the cross-linked polymer structure and their effect on the chemical, physical and gas transport properties with an aim to develop rational, molecular-based design rules for tailoring separation performance. Experimental results from calorimetric and dynamic thermal analysis studies are presented, along with pure gas permeability and solubility obtained at 35°C. Incorporation of dangling side chains by copolymerization of PEGDA with methoxy-terminated poly(ethylene glycol) methyl ether acrylate, n=8 (PEGMEA) was previously shown to be effective in increasing fractional free volume of XLPEO through the opening of local free volume elements, which in turn increased CO₂ permeability. Through a comparative study ofshort chain analogs to these co-monomers, incorporation of an ethoxy-terminated co-monomer was shown to be more effective than a comparable methoxy-terminated co-monomer in increasing gas permeability. For instance, copolymerization of PEGDA with 71 wt% ethoxy-terminated diethylene glycol ethyl ether acrylate increased CO₂ permeability from 110 barrer to 320 barrer. Gas permeability increase was not observed when hydroxy or phenoxy-terminated pendants were introduced, which was attributed to reduction in chain mobility due to increased inter-chain chemical interactions or steric restrictions, respectively. Based on these results, incorporation of a co-monomer containing a bulky non-polar terminal group, tris-(trimethylsiloxy)silyl, was examined in order to further increase gas permeability. Addition of 80 wt% TRIS-A co-monomer increased CO₂ permeability of cross-linked PEGDA to 800 barrer. However, the resulting changes in chemical character of the copolymer reduced CO₂/light gas selectivity, even as gas permeability increased. The effect of incorporating a bulky, stiff functional group in the cross-linker chain was studied using cross-linked bisphenol-A ethoxylate diacrylate, which showed 40% increase in permeability compared to cross-linked PEGDA. This study affirmed the importance of polymer chain interaction, in addition to free volume, in determining the gas transport properties of the polymer. / text

L'objectif de cette thèse est de synthétiser de nouveaux monomères éthers vinyliques porteurs de groupements phosphonate, dans le but d'étudier leur efficacité comme retardateurs de flamme. Les produits phosphorés s'avèrent de bonnes alternatives aux retardateurs de flamme halogénés, qui présentent des problèmes environnementaux. Dans un premier temps, nous avons réalisé la synthèse des éthers vinyliques phosphonés par transéthérification de l'éthylvinyl éther en présence d'alcools phosphonés. Ensuite, nous avons choisi la copolymérisation radicalaire (A/D) afin de préparer des copolymères à base d'éthers vinyliques phosphonés et de différents accepteurs. Des études cinétiques par Infra-Rouge en temps réel et plusieurs méthodes d'analyses ont été effectuées afin de caractériser ces copolymères. Dans un second temps, nous avons réalisé des cinétiques de photocopolymérisation radicalaire du 2-vinyloxyéthylphosphonate de diméthyle avec une série de monomères accepteurs, par exemple, les maléimides avec qui ce monomère forme des complexes forts. La photopolymérisation cationique a aussi été réalisée et offre de meilleurs résultats que la photopolymérisation radicalaire. Un bilan de tous les polymères phosphonés a été réalisé dans le but de tester leurs performances en tant que retardateurs de flamme. Les caractérisations thermogravimétriques et microcalorimétriques de ces copolymères ont montré une quantité importante de résidus et des valeurs de chaleur dégagée encourageantes en vue d'une utilisation de ceux-ci en tant que retardateurs de flamme. / The aim of this work is the synthesis of new vinyl ethers monomers bearing phosphonate groups, in order to study their efficiency as flame retardants. Phosphorus products are known to be a good alternative to halogenated flame retardants, which are involved in environmental problems. Initially, the synthesis of phosphonated vinyl ethers was performed by trans-etherification of ethylvinyl ether in the presence of phosphonated alcohols. Then, the radical copolymerization (A/D) was used to prepare copolymers based on phosphonated vinyl ether and various electron-accepting monomers. Kinetic studies by real-time Infrared and several methods of analyzes were used to characterize these copolymers. In a second step, the radical photocopolymerization of 2-dimethylvinyloxyethylphosphonate was led with a series of electron-accepting monomers, for instance maleimides which form strong complexes with vinyl ethers. The cationic photopolymerization of these phosphonated vinyl ethers is also possible and affords better results than radical photopolymerization. An assessment of all phosphonated polymers was performed in order to test their performances as flame retardants. Thermogravimetric and microcalorimetric characterizations showed good amount of released residues showing that these copolymers are good candidates as flame retardants.