Acrylonitrile based engineering random copolymers were prepared via one step emulsion polymerization using ammonium persulfate (initiator), 1-dodecanthiol (chain transfer agent) and DOWFAX 8390 (surfactant) in the presence of water at approximately 65 0C. Three copolymer compositions were studied for novel polyacrylonitrile, (PAN)-polyhydroxyethyl acrylate (PHEA), PAN-polybutyl acrylate (PBA), novel PAN-polyt-butyl acrylate (PtBA), PAN-polyethyl acrylate (PEA) and PAN-polymethyl acrylate (PMA) with acrylate content varying from 8, 12 and 16 molar percent. Infrared spectroscopy, proton and carbon NMR were successfully utilized to confirm the chemical structure of copolymers. In order to determine the comonomer compositions in the copolymer structure, proton nuclear magnetic resonance, 1H NMR studies were carried out. Thermal (TGA, DSC) and mechanical properties of homo and copolymers were also investigated. Intrinsic viscosity (IV) measurements in dimethyl formamide (DMF) solution revealed that the molecular weight of the copolymers were quite enough to form ductile films. In this study, hydrogels and their copolymers of acrylonitrile (PAN-PHEA) were also studied. Some properties of the free standing copolymer films such as / swelling behaviors and densities were evaluated. It was also demonstrated that the nanocomposites of these copolymers could be utilized in filtration technology. Hence, novel PAN(88)-co-PMA(12) and polyaniline (PANI) nanocomposites were prepared at various PANI loadings to remove toxic chromium(VI) solution from water. Chemical structure, swelling and fracture morphology of the nanocomposites membranes were studied. It was observed that PANI had a great impact on the chromium removal. Permeate flux and rejection of chromium(VI) were demonstrated for various pHs and chromium(VI) concentrations. Finally, influences of comonomer composition on the thermal properties of the copolymers were investigated to input their structure property relation.

The photopolymerization of multifunctional acrylates leads to the formation of a complex and insoluble network due to cross-linking. This characteristic is a useful property for stereolithography applications, where solid parts of the desired shape are cured using a pre-determined energy exposure profile. Traditionally, the required energy exposure is determined using a critical energy--depth of penetration, or Ec--Dp, model. The parameters Ec and Dp, are usually fit to experimental data at a specific resin composition and cure intensity. As a result, since the Ec--Dp model does not explicitly incorporate cure kinetics, it cannot be used for a different set of process conditions without first obtaining experimental data at the new conditions. Thus, the Ec--Dp model does not provide any insight when a new process needs to be developed, and the best processing conditions are unknown. The kinetic model for multifunctional acrylate photopolymerization presented here is based on a set of ordinary differential equations (ODE), which can be used to predict part height versus exposure condition across varying resin compositions. Kinetic parameter information used in the model is obtained by fitting the model to double bond conversion data from Fourier Transform Infrared Spectroscopy (FTIR) measurements. An additional parameter, the critical conversion value, is necessary for determining the formation of a solid part of the desired height. The initial rate of initiation, Ri, combines all the factors that impact part height, and therefore, it is an important quantity that is required in order to find the critical conversion value. The critical conversion value is estimated using the Ri and Tgel value from microrheology measurements. Information about network connectivity, which can be used to get properties such as molecular weight, cannot be derived from models using traditional mass-action kinetics for the cross-linking system. Therefore, in addition to modeling the reaction using the ODE based model, the results from a statistical model based on Kinetic Monte Carlo (KMC) principles are also shown here. The KMC model is applicable in situations where the impact of chain length on the kinetics or molecular weight evolution is of interest. For the present project, the detailed information from network connectivity was not required to make part height predictions, and the conversion information from the ODE model was sufficient. The final results show that the kinetic ODE model presented here, based on the critical conversion value, captures the impact of process parameters such as initiator concentration, light intensity, and exposure time, on the final part height of the object. In addition, for the case of blanket cure samples, the part height predictions from the ODE model make comparable predictions to the Ec--Dp model. Thus, the ODE model presented here is a versatile tool that can be used to determine optimum operating conditions during process development.

Grouting techniques have been in used for many years, but several new grout materials have surfaced in recent decades that have re-defined the boundaries of the limitations of grouting programs. Typically these applications are used for seepage control in earthen impoundments, but strength of these earthen impoundments should be considered where there is potential for movement in the grouted soil mass. This study investigated initial conditions that could affect grout application effectiveness. The initial conditions in question were soil grain size and in situ moisture content. Two grouts were used, ultrafine and acrylate, and variations in pure grout properties were studied. An apparatus was developed so that a uniform grout could penetrate the pore spaces of a soil specimen. The rate of penetration of the grout into the soil was studied. The unconfined compressive strength of the resulting grouted soil was then analyzed. In testing neat ultrafine grout, it was shown that increased water-to-cement ratios had negative effects on the stability of the grout. Increasing the water-to-cement ratio from 0.5 to 2.5 resulted in a decrease in strength by a factor of 100. An inhibitor chemical was used to increase the time for reaction in the acrylate grout. During the chemical reaction, the curing temperature and gel times were monitored. A grout mix was selected for the acrylate grout that achieved appropriate gel times. In general, this study found that the grout penetrations rates into the soil increased as the initial moisture was increased from dry conditions to a gravimetric moisture content of nine percent. In each study, increased initial moisture decreased the grouted soil strength, with decreases in strength exceeding 50 percent. Empirical relationships were realized when compared to the initial matric suction of the soil. This suggests initial matric suction may be a useful initial condition for estimating increases in soil strength upon implementation of a grouting program for both the acrylate and ultrafine grouts.

Magnetic particles have attracted increasing attention in fields ranging from separation processes to electromagnetic information storage an medical application. Various approaches for their synthesis have been developed and studied to satisfy the criteria of production. Improvement and optimization of size, stability, and functionality is of vital importance in biological applications. The main aspect of project, initially, was to study the application of aqueous functionalized magnetic nanoparticles coupled with high gradient magnetic separation technique for the removal of trace residue of organic contaminants from drinking water. However, the importance of synthesizing stable ferrofluid for this purpose became clear later and took precedence over the initial objective. Different approaches were adopted, such as the incorporation of poly(ethylene glycol) methacrylate, ethylenediamine, and chitosan, to enhance the stability of magnetic particles. However, these surface modifications had unfavorable effect on the stability of initial particles. In accord with the initial objective of the project, the possibility of utilization of β-cyclodextrin, as organic pollutant entrapment agent, was investigated in preliminary studies conducted on its interaction with a model compound, procaine hydrochloride. The outcomes of these experiments suggest its potential as a biocompatible removal agent for the elimination of organic pollutant in drinking water system, or other applications that require selective separation of organic compounds.

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.

The objective of this work is to characterize and understand structure- mechanical property relationships in (meth)acrylate networks. The networks are synthesized from mono-functional (meth)acrylates with systematically varying sidegroup structure and multi-functional crosslinkers with varying mole fraction and functionality. Fundamental trends are established between the network chemical structure, crosslink density, glass transition temperature, rubbery modulus, failure strain, and toughness. The glass transition temperature of the networks ranged from -29 to 112 °C, and the rubbery modulus ranged from 2.8 to 129.5 MPa. At low crosslink density (Er < 10 MPa) network chemistry has a profound effect on network toughness. At high crosslink densities (Er > 10 MPa), network chemistry has little influence on material toughness. The characteristic ratio of the mono-functional (meth)acrylates components is unable to predict trends in thermoset toughness as a function of chemical structure, as is accomplished for thermoplastics. The cohesive energy density is a better tool for prediction of network mechanical properties. Due to superior mechanical properties, networks with phenyl ring sidegroups are further investigated to understand the effect of phenyl ring distance on toughness. This work provides a fundamental basis for designing (meth)acrylate shape memory polymer networks with specific failure strain, toughness, glass transition temperature, and rubbery modulus.

The research described herein is aimed at exploring the thermo-mechanical properties of thiol-ene polymers in bulk form, investigating the ability of thiol-ene polymers to behave desirably as photolithographic media, and providing the first characterization of the mechanical properties of two-photon stereolithography-produced polymer structures. The thiol-ene polymerization reaction itself is well-characterized and described in the literature, but the thermomechanical properties of thiol-ene and thiol-ene/acrylate polymers still require more rigorous study. Understanding the behavior of thiol-ene networks is a crucial step towards their expanded use in bulk form, and particularly in specialized applications such as shape memory devices. Additionally, the thiol-ene polymerization reaction mechanism exhibits unique properties which make these polymers well suited to photolithography, overcoming the typical dichotomy of current materials which either exhibit excellent photolithographic behavior or have controllable properties. Finally, before two-photon stereolithography can create mechanisms and devices which can serve any mechanically functional role, the mechanical properties of the polymers they produce must be quantitatively characterized, which is complicated by the extremely small scale at which these structures are produced. As such, mechanical characterization to date has been strictly qualitative. Fourier transfer infrared spectroscopy revealed functional group conversion information and sol-fraction testing revealed the presence of unconverted monomer and impurities, while dynamic mechanical analysis and tensile testing revealed the thermomechanical responses of the systems. Nanoindentation was employed to characterize the mechanical properties of polymers produced by two-photon stereolithography. Optical and electron microscopy were exploited to provide quantitative and qualitative evaluations of thiol-ene/acrylate performance in small-scale polymerization regimes. The broad objective of the research was to explore thiol-ene polymer behavior both in bulk and at the small scale in an effort to supplement the material library currently used in these fields and to expand the design envelope available to researchers. The significance of the research is the advancement of a more complete and fundamental understanding of thiol-ene polymerization from kinetics to final properties, the quantitative establishment of the mechanical properties of materials created with two-photon stereolithography, and the comprehensive characterization of a supplementary class of photopatternable polymers with greater property tunability than is possible with currently used materials.

Os processos industriais de polimerização em emulsão são normalmente realizados em reatores batelada ou semi batelada ou em tanques agitados contínuos (CSTR). Os reatores contínuos têm a vantagem de terem menor porte e de propiciarem melhor controle de qualidade do produto através da redução de variações de batelada a batelada. Além disso, as oscilações periódicas autosustentadas na conversão de monômero e no tamanho da partícula, que são normalmente observadas em reatores do tipo CSTR, podem ser minimizadas em reatores tubulares mediante o uso de dispositivos de mistura estáticos adequados combinados com escoamento pulsado (oscilatório). O objetivo deste trabalho é apresentar o desenvolvimento de uma copolimerização em emulsão de acetato de vinila e acrilato de butila em uma coluna pulsada com pratos perfurados (CPPP). A fim de aumentar a sua flexibilidade operacional, a coluna é composta de 5 seções, cada uma apresentando controles independentes de alimentação lateral e temperatura. Dependendo da estratégia de alimentação de monômero, pode-se notar uma deriva de composição durante o processo de copolimerização em emulsão do acetato de vinila e acrilato de butila devido às grandes diferenças entre estes monômeros em suas razões de reatividade e nas solubilidades na fase aquosa. Neste caso, a CPPP propicia diferentes possibilidades de alimentação que permitem controlar a composição do copolímero através da alimentação do monômero mais reativo ao longo da coluna. Por esta razão, foi avaliado neste estudo o efeito do número de correntes de alimentação sobre as propriedades do polímero. Diferentes números de correntes laterais de alimentação de monômero foram empregadas nos ensaios experimentais. Diferenças na uniformidade da composição do copolímero podem ser notadas dependendo do número de correntes laterais de alimentação aplicadas em cada teste. A fim de permitir variações de temperatura, somente a temperatura de entrada das camisas de resfriamento foi fixada. Para simular as reações foi utilizado um modelo matemático desenvolvido baseado no modelo de escoamento pistonado (plug-flow) axialmente disperso. No presente trabalho, um balanço de energia foi incluído ao modelo matemático anterior de modo que a influência de diferentes perfis de temperatura pudesse ser considerada. O efeito das correntes laterais de alimentação de monômero sobre as propriedades do copolímero puderam ser previstas com suficiente precisão pelas simulações do modelo, as quais foram também validadas pelos resultados experimentais. Com base nas simulações matemáticas, um perfil ótimo de alimentação pôde ser calculado e experimentalmente aplicado na CPPP permitindo a produção de um copolímero mais homogêneo. Os resultados também permitiram a validação do modelo matemático como uma ferramenta confiável na predição de ensaios experimentais. Além disso, as vantagens da CPPP puderam ser verificadas pelo seu desempenho adequado como reator tubular para processos contínuos de copolimerização em emulsão. Finalmente, os resultados indicaram a possibilidade de melhorias adicionais nas propriedades do polímero através do emprego de diferentes temperaturas e perfis de alimentação de outros reagentes ao longo da coluna. / Industrial emulsion polymerization processes are usually performed in batch or semi-batch stirred tanks, or in continuous stirred tank reactors (CSTR). Continuous reactors have the advantage of being smaller and providing a better product quality control by the reduction of the batch-to-batch variations. In addition, periodical self-sustained oscillations in monomer conversion and in particle size that are usually observed in CSTR can be minimized in tubular reactors presenting good radial mixing. Such conditions can be achieved in tubular reactors by using adequate static mixing devices combined with pulsed (oscillatory) flow. The aim of this work is to report the development of a continuous emulsion copolymerization of vinyl acetate and butyl acrylate performed in a pulsed sieve plate column (PSPC). In order to improve its operational flexibility, the column is composed of five sections, each one presenting independent lateral feed and temperature controls. Depending on the monomer feeding strategy, a composition drift can be noticed during the emulsion copolymerization process of vinyl acetate and butyl acrylate, due to the large differences in reactivity ratios and aqueous phase solubility between these monomers. In this case, the PSPC provides different operational feeding possibilities which allow controlling the copolymer composition by feeding the more reactive monomer along the column. For this reason, in this study the effect of the number of lateral feed streams on the polymer properties was evaluated. Different numbers of lateral monomer feed streams were employed in the experimental runs. Differences in the uniformity of the copolymer composition can be noticed along the reactor depending on the number of lateral feed streams applied in each test. In order to allow temperature variations, during each reaction only the inlet temperature of the cooling jackets was fixed. A developed mathematical model based on the axially dispersed plug-flow model was used to simulate the reactions. In the present study the energy balance was included in the mathematical model so that the influence of different temperature profiles could be taken into account. The effect of lateral monomer feed streams over the copolymer properties could be predicted with sufficient accuracy by model simulations which were also validated by the experimental results. Based on mathematical simulations, an optimal feeding profile could be calculated and experimentally applied in the PSPC allowing the production of a more homogeneous copolymer. The results also permitted the validation of the mathematical model as a reliable tool in the prediction of experimental runs. Furthermore, the advantages of the PSPC could be verified by its adequate performance as a tubular reactor for continuous emulsion copolymerization processes. Finally, the results indicate the possibility of further improvements in other polymer properties by employing different temperature and feeding profiles of other reagents along the column.

Doctor of Philosophy / Department of Grain Science and Industry / X. Susan Sun / A demand in sustainable polymers has been increased because of the environment concerns and saving finite petroleum resources. Plant oils are promising renewable resources to produce environmentally friendly polymer applications. Soybean oil-based resins such as epoxidized soybean oil (ESO) and acrylated epoxidized soybean oil (AESO) have been well-known functionalized plant oils, but relatively low performances of their polymers and a competition with food production have been disadvantages. Thus, in this study, we designed new plant oil-based acrylates using non-food resources and achieved excellent properties of the acrylates for coatings and thermoset applications. Firstly, we developed coating materials with high mechanical, thermal and coating performances using acrylated epoxidized camelina oil (AECO) as a main acrylate monomer with various meth(acrylates) as reactive diluents Next, acrylated epoxidized cardanol modified fatty acids from camelina oil (AECFA) was successfully synthesized, and a phenolic structure with long aliphatic side chains with acrylic groups was obtained. The novel structure of AECFA provided rigidity into its polymer maintained with flexibility, and AECFA coating material showed better performances in terms of all properties such as mechanical, thermal, viscoelastic, and coating performances, as compared to commercial AESO resin. Finally, acrylated epoxidized allyl 10-undecenoate (AEAU) was developed from 10-undecenoic acid, castor oil derivative. The single fatty ester structure with di-functional acrylates of AEAU had very lower viscosity and showed better thermoset performances than those of triglyceride-based acrylates such as AESO and AECO. Thus, AEAU had a potential to an alternative to AESO for thermoset applications.

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