The basis for this research project is based on the discovery in the previous research that 2,2' ,5-trimethyl-3-( I-phenylethoxy)-4-tert-butyl-3-azahexane, (Styryl- TITNO) is able to control bulk polymerization of styrene at temperature as low as 70°C. The principle objective of this project was to evaluate the feasibility of using Styryl- TITNO to control radical solution and miniemulsion polymerizations at temperatures below 100°C. Styryl- TITNO was shown to effect solution polymerizations of both n-butyl acrylate (BA) and styrene below 100°C. Polymerization temperature was shown to be a crucial parameter for achieving control in Styryl- TITNO -mediated polymerizations. Good control of the number-average molecular weight (Mn) and molecular weight dispersity for the polymerization of BA was observed at 90°C. However, a lower temperature of 70 °C is required for good control of styrene polymerization. Living characteristics of polymer chains were demonstrated by a sequential chain extension of TITNO -terminated PBA with styrene at 90°C to form poly(n-butyl acrylate)- block-poly[(n-butyl acrylate)-co-styrene], [pBA-b-P(BA-co-PS)], block copolymers. An improvement in livingness in these reactions was observed when the second P(BAlstyrene) block was formed at 70°C after the first PBA block was produced at 90°C. Kinetics studies facilitated determination of the activation-deactivation equilibrium constant (K), which for styrene polymerization at 90°C (K = 4.1 x 10.9 mol L-J at 90°C and 3.0 x 10-9 mol L-J at 70 "C) is nearly an order of magnitude higher than that for BA polymerization at the same temperature (K = 8.5 x 10-11 mol L-I). This is the reason why BA polymerization shows better control than styrene polymerization at 90°C. The activation energy (Ea) for thermolysis of Stryl- TITNO is 104.1 kJ mol", which is relatively low compared to the literature values of Ea for various styryl alkoxymines. This explains why Styryl- TITNO is able to effect polymerization at temperatures as low as 70 "C. The studies of Styryl- TITNO-mediated miniemulsion polymerizations at 90 "C indicate that accumulation of free TITNO• in the particles is an issue for use of Styryl- TITNO in miniemulsion polymerizations. The use of L-ascorbic acid (L-AA) and L-ascorbic acid 6-palmitate (L-AAP) as nitroxide scavengers to reduce the level of free TITNO • in the polymerization was investigated. The best result was observed for the polymerization of BA in the presence of 5.35 mol% of L-AAP relative to Styryl- TITNO, which attained 48% conversion after 5 h. The chain extension of isolated TITNO -terminated PBA, TITNO -PBA, was used to examine the livingness of - polymer -chains before the rate of polymerization was severely retarded. The livingness of TITNO-PBA was evidenced by a shift of the staring PBA molecular weight distribution towards higher molecular weight, which provides solid evidence that the majority of polymer chains remained living. Thus, it can be concluded with certainty that the accumulation of free TITNO• was mainly responsible for the suppression of polymerization in miniemulsion polymerizations mediated by Styryl- TITNO.

As características inovadoras dos microreatores permitem a produção de novos materiais. O presente trabalho analisa o comportamento do milirreator ASIA da Syrris para a polimerização de estireno em solução. Realizaram-se polimerizações á 100 °C e 115 °C, usando peróxido de benzoíla como iniciador e tolueno como solvente. Testaram-se diferentes razões monômero solvente e diferentes quantidades de iniciador, além de variar o tempo de residência entre 5 e 80 minutos. As variações dos parâmetros envolvidos nesse milirreator proporcionou conversões de 9% até quase 70%, com pesos moleculares numéricos entre 6,000 e 50,000 g/mol. Não houve entupimento no reator, permitindo a aplicação de condições mais agressivas e melhor controladas. Fez-se uma primeira tentativa de modelagem, usando o modelo do PFR e, em seguida, da dispersão axial. Usou-se o método dos momentos para computar as médias da distribuição do peso molecular. As simulações forneceram uma razoável previsão da conversão e do peso molecular médio para os experimentos mais diluídos, mas se distanciaram para os casos com maior concentração de monômero e com maior polidispersão, sendo isso provavelmente resultado do desvio do comportamento de fluxo em pistão. Portanto, o milirreator ASIA é capaz de controlar bem as reações de polimerização, (proporcionando baixos valores do índice de polidispersão), além de fornecer valores satisfatórios de conversão (tendo em conta do seu pequeno tamanho). O sucesso no controle das polimerizações pode certamente permitir o scale-up de um reator com tais características, de forma a empregá-lo para produtividades maiores de polímeros com boa qualidade. / The innovative characteristics of microreactors allow producing new materials. The present work analyses the behavior of the Syrris ASIA millireactor for the solution polymerization of styrene. The polymerizations were carried out at 100 °C and 115 °C, using benzoyl peroxide as initiator and toluene as solvent. Different monomer to solvent ratios and initiator quantities have been tested, besides varying the residence time from 5 to 80 minutes. The variations of the parameters involved in this millireactor gave conversions from 9% to almost 70%, with numerical molecular weights ranging from 6,000 to 50,000 g/mol. No plugging happened, opening the possibility of more aggressive and well controlled applications. A first attempt of modeling was made, using the PFR model and the dispersion model. The method of moments was adopted to compute the means of the molecular weight distribution. The simulations gave a good prediction of conversion and average molecular weight for the more diluted experiments, but partially deviated for higher monomer contents with larger polydispersities, meaning a larger discrepancy from plug flow for the millireactor. In general, the millireactor ASIA can be concluded to control polymerization reactions well (giving low polydispersity index values), besides giving satisfactory conversion values (considering its small size). Succeeding in controlling polymerizations can provide a reactor with characteristics of being scaled up and employed in greater productivities, ensuring good polymer qualities.

As características inovadoras dos microreatores permitem a produção de novos materiais. O presente trabalho analisa o comportamento do milirreator ASIA da Syrris para a polimerização de estireno em solução. Realizaram-se polimerizações á 100 °C e 115 °C, usando peróxido de benzoíla como iniciador e tolueno como solvente. Testaram-se diferentes razões monômero solvente e diferentes quantidades de iniciador, além de variar o tempo de residência entre 5 e 80 minutos. As variações dos parâmetros envolvidos nesse milirreator proporcionou conversões de 9% até quase 70%, com pesos moleculares numéricos entre 6,000 e 50,000 g/mol. Não houve entupimento no reator, permitindo a aplicação de condições mais agressivas e melhor controladas. Fez-se uma primeira tentativa de modelagem, usando o modelo do PFR e, em seguida, da dispersão axial. Usou-se o método dos momentos para computar as médias da distribuição do peso molecular. As simulações forneceram uma razoável previsão da conversão e do peso molecular médio para os experimentos mais diluídos, mas se distanciaram para os casos com maior concentração de monômero e com maior polidispersão, sendo isso provavelmente resultado do desvio do comportamento de fluxo em pistão. Portanto, o milirreator ASIA é capaz de controlar bem as reações de polimerização, (proporcionando baixos valores do índice de polidispersão), além de fornecer valores satisfatórios de conversão (tendo em conta do seu pequeno tamanho). O sucesso no controle das polimerizações pode certamente permitir o scale-up de um reator com tais características, de forma a empregá-lo para produtividades maiores de polímeros com boa qualidade. / The innovative characteristics of microreactors allow producing new materials. The present work analyses the behavior of the Syrris ASIA millireactor for the solution polymerization of styrene. The polymerizations were carried out at 100 °C and 115 °C, using benzoyl peroxide as initiator and toluene as solvent. Different monomer to solvent ratios and initiator quantities have been tested, besides varying the residence time from 5 to 80 minutes. The variations of the parameters involved in this millireactor gave conversions from 9% to almost 70%, with numerical molecular weights ranging from 6,000 to 50,000 g/mol. No plugging happened, opening the possibility of more aggressive and well controlled applications. A first attempt of modeling was made, using the PFR model and the dispersion model. The method of moments was adopted to compute the means of the molecular weight distribution. The simulations gave a good prediction of conversion and average molecular weight for the more diluted experiments, but partially deviated for higher monomer contents with larger polydispersities, meaning a larger discrepancy from plug flow for the millireactor. In general, the millireactor ASIA can be concluded to control polymerization reactions well (giving low polydispersity index values), besides giving satisfactory conversion values (considering its small size). Succeeding in controlling polymerizations can provide a reactor with characteristics of being scaled up and employed in greater productivities, ensuring good polymer qualities.

Poly(N-vinylcaprolactam), PNVCL, is a nonionic, nontoxic, water soluble, thermally sensitive and biocompatible polymer. It contains hydrophilic carboxylic and amide groups with hydrophobic carbon-carbon backbone chain so its hydrolysis does not produce small amide compounds which are often not desired for biomedical applications. Moreover PNVCL possesses lower critical solution temperature, (LCST) in the range of physiological temperature (32-34 oC). These properties make the polymer suitable for use in some biotechnology applications such as implantation of artificial organs and tissues, purification of enzymes, proteins and living cells, and in drug release systems. In this study PNVCL was synthesized by free radical polymerization with solution technique. Polymerization was done at different temperatures for different time periods in an oil bath. The activation energy for polymerization was found from Arrhenius plot as 108.4 kJ/mol. Polymer was characterized by FT-IR, 1H-NMR and 13C-NMR, DSC, TGA and XRD techniques. FT-IR and NMR measurements confirmed that the polymerization proceeded through the vinyl group.

Poly(2-Hydroxyethyl acrylate), PHEA, is used as hydrophilic polymeric gels which have been studied because of its great importance for agricultural or biomedical applications. Biomedical applications of hydrogels include soft contact lenses, artificial corneas, soft tissue substitutes and burn dressings. In this study, it was aimed to synthesis the polymers with well-defined molecular weights, polydispersities and cahin topologies. Bulk, solution and atom transfer radical polymerization (ATRP) techniques at different temperatures were examined. The polymerization in bulk form was carried in vacuum and in open atmosphere. The polymerization curves showed autoacceleration mechanism. The polymers obtained were insoluable in most common solvents because of having high molecular weights and are crosslinked. So in order to overcome this problem, 2-hydroxyethyl acrylate was polymerized by solution and ATRP methods. The activation energy for bulk polymerization was found from Arrhenius plot. The polymer was characterized by FT-IR, DSC, TGA, 1H and 13C NMR techniques, Tensile tests were also examined for PHEA.

Acetylenedicarboxylic acid monopotassium salt, ADCA-K, was polymerized by radiation induced solid-state and chemical initiator induced solution polymerization methods. Radiation induced solid-state polymerization was carried out by Co-60 g-radiation at room temperature. The powder polymer obtained was soluble in water but insoluble in common organic solvents. The solution polymerization initiated by benzoylperoxide was carried out in an oil bath at 90&deg / C. The polymer obtained was soluble in water but insoluble in dimethylsulfoxide. In the first stage of the polymerization, H2O, CO and/or CO2 gases were evolved and the polymerization was proceeded on the acetylene group. The polymers obtained were characterized by FT-IR, DSC, TGA-FTIR, NMR and DP-MS methods. The crystal structure effect on polymerization was investigated by X-Ray method. The monomer is monoclinic with a space group of C2/c. The unit cell parameters are a=795.4, b=1192.6, c=591.8 pm and b=105.40. Polymer showed a partial polycrystalline structure. The larger fraction of polymer has identical crystal structure to that of the monomer. Therefore, polymerization takes place a topotactic mechanism.

Dynamic modelling and optimization of three different processes namely (a) bulk polymerization of styrene, (b) solution polymerization of methyl methacrylate (MMA) and (c) emulsion copolymerization of Styrene and MMA in batch and semi-batch reactors are the focus of this work. In this work, models are presented as sets of differential-algebraic equations describing the process. Different optimization problems such as (a) maximum conversion (Xn), (b) maximum number average molecular weight (Mn) and (c) minimum time to achieve the desired polymer molecular properties (defined as pre-specified values of monomer conversion and number average molecular weight) are formulated. Reactor temperature, jacket temperature, initial initiator concentration, monomer feed rate, initiator feed rate and surfactant feed rate are used as optimization variables in the optimization formulations. The dynamic optimization problems were converted into nonlinear programming problem using the CVP techniques which were solved using efficient SQP (Successive Quadratic Programming) method available within the gPROMS (general PROcess Modelling System) software. The process model used for bulk polystyrene polymerization in batch reactors, using 2, 2 azobisisobutyronitrile catalyst (AIBN) as initiator was improved by including the gel and glass effects. The results obtained from this work when compared with the previous study by other researcher which disregarded the gel and glass effect in their study which show that the batch time operation are significantly reduced while the amount of the initial initiator concentration required increases. Also, the termination rate constant decreases as the concentration of the mixture increases, resulting rapid monomer conversion. The process model used for solution polymerization of methyl methacrylate (MMA) in batch reactors, using AIBN as the initiator and Toluene as the solvent was improved by including the free volume theory to calculate the initiator efficiency, f. The effects of different f was examined and compared with previous work which used a constant value of f 0.53. The results of these studies show that initiator efficiency, f is not constant but decreases with the increase of monomer conversion along the process. The determination of optimal control trajectories for emulsion copolymerization of Styrene and MMA with the objective of maximizing the number average molecular weight (Mn) and overall conversion (Xn) were carried out in batch and semi-batch reactors. The initiator used in this work is Persulfate K2S2O8 and the surfactant is Sodium Dodecyl Sulfate (SDS). Reduction of the pre-batch time increases the Mn but decreases the conversion (Xn). The sooner the addition of monomer into the reactor, the earlier the growth of the polymer chain leading to higher Mn. Besides that, Mn also can be increased by decreasing the initial initiator concentration (Ci0). Less oligomeric radicals will be produced with low Ci0, leading to reduced polymerization loci thus lowering the overall conversion. On the other hand, increases of reaction temperature (Tr) will decrease the Mn since transfer coefficient is increased at higher Tr leading to increase of the monomeric radicals resulting in an increase in termination reaction.

Dynamic modelling and optimization of three different processes namely (a) bulk polymerization of styrene, (b) solution polymerization of methyl methacrylate (MMA) and (c) emulsion copolymerization of Styrene and MMA in batch and semi-batch reactors are the focus of this work. In this work, models are presented as sets of differential-algebraic equations describing the process. Different optimization problems such as (a) maximum conversion (Xn), (b) maximum number average molecular weight (Mn) and (c) minimum time to achieve the desired polymer molecular properties (defined as pre-specified values of monomer conversion and number average molecular weight) are formulated. Reactor temperature, jacket temperature, initial initiator concentration, monomer feed rate, initiator feed rate and surfactant feed rate are used as optimization variables in the optimization formulations. The dynamic optimization problems were converted into nonlinear programming problem using the CVP techniques which were solved using efficient SQP (Successive Quadratic Programming) method available within the gPROMS (general PROcess Modelling System) software. The process model used for bulk polystyrene polymerization in batch reactors, using 2, 2 azobisisobutyronitrile catalyst (AIBN) as initiator was improved by including the gel and glass effects. The results obtained from this work when compared with the previous study by other researcher which disregarded the gel and glass effect in their study which show that the batch time operation are significantly reduced while the amount of the initial initiator concentration required increases. Also, the termination rate constant decreases as the concentration of the mixture increases, resulting rapid monomer conversion. The process model used for solution polymerization of methyl methacrylate (MMA) in batch reactors, using AIBN as the initiator and Toluene as the solvent was improved by including the free volume theory to calculate the initiator efficiency, f. The effects of different f was examined and compared with previous work which used a constant value of f 0.53. The results of these studies show that initiator efficiency, f is not constant but decreases with the increase of monomer conversion along the process. The determination of optimal control trajectories for emulsion copolymerization of Styrene and MMA with the objective of maximizing the number average molecular weight (Mn) and overall conversion (Xn) were carried out in batch and semi-batch reactors. The initiator used in this work is Persulfate K2S2O8 and the surfactant is Sodium Dodecyl Sulfate (SDS). Reduction of the pre-batch time increases the Mn but decreases the conversion (Xn). The sooner the addition of monomer into the reactor, the earlier the growth of the polymer chain leading to higher Mn. Besides that, Mn also can be increased by decreasing the initial initiator concentration (Ci0). Less oligomeric radicals will be produced with low Ci0, leading to reduced polymerization loci thus lowering the overall conversion. On the other hand, increases of reaction temperature (Tr) will decrease the Mn since transfer coefficient is increased at higher Tr leading to increase of the monomeric radicals resulting in an increase in termination reaction.