Hydrophilic poly(2-hydroxyethyl methacrylate), PHEMA, and hydrophobic poly(dimethyl siloxane), PDMS, segments containing copolymers have been widely used as a biomaterial. These amphiphilic copolymers also used as an emulsifying agent in polymer solutions and compatibilizer in polymer blends. In this case, solution polymerizations of HEMA by radiation, ATRP and RAFT methods were studied. The thermal degradation mechanism of PHEMA, which was prepared in aqueous solution by gamma radiation technique, was studied in detail. The DSC, TGA and Mass Spectroscopy analyses revealed that the degradation is linkage and depolymerization with a combination of monomer fragmentation. The ATRP of HEMA was performed with ethyl-2-bromoisobutyrate (EBriB) initiator and CuCl/bipyridine catalyst in MEK/1-propanol solvent mixture. Cu(II) complexes and PHEMA obtained via ATRP were characterized by UV-vis, FTIR and 1H-NMR analysis. The RAFT polymerization of HEMA with different [RAFT]/[AIBN] ratios were also investigated in three solvents (methyl ethylketone, ethyl acetate and toluene). The controlled polymerization of HEMA with the ratio of [RAFT]/ [AIBN]=18 at 80 oC in MEK and ethyl acetate, shows the first-order kinetic up to the nearly 40 % conversion Macroazoinitiator PDMS-MAI was synthesized from bifunctional PDMS and then copolymerized with MMA, EMA, HEMA and TMS-HEMA monomers Different characterization methods such as FTIR, 1H-NMR, solid state NMR, GPC, XPS, SEM, DSC, etc. have been used for the characterization of block copolymers. P(DMS-b-TMSHEMA) was converted to the P(DMS-b-HEMA) block copolymer by deprotection of TMS groups. The phase separated morphology was observed for the P(DMS-b-HEMA) copolymer, which was different from P(DMS-b-MMA) and P(DMS-b-EMA) copolymers.

Hollow fiber membranes are widely used in blood oxygenators to remove carbon dioxide and add oxygen during cardiopulmonary bypass operations. These devices are now widely used off-label by physicians to perform extracorporeal blood oxygenation for patients with lung failure. Unfortunately, the hollow fiber membranes used in these devices fail prematurely due to blood plasma leakage and gas emboli formation. This project formed ultrathin (~100nm) polymer coatings on polymer hollow fiber membranes. The coatings were intended to “block” existing pores on the exterior surfaces while permitting high gas fluxes. This coating is synthesized using surface imitated control radical polymerization. The coating was durable and did not peel or degrade. Fibers modified using this coating technique did not substantially degrade the mechanical properties of the membrane. This coating technique prevented blood plasma leakage and gas emboli formation. The coating permitted blood oxygenation and carbon dioxide removal from in a mock circulation module. Coating formation on polymeric hollow fiber membranes using surface initiated controlled radical polymerization allows for the formation of membranes that have the potential for long term blood oxygenation. This coating technique would allow these long term blood membranes to be produced more inexpensively than currently existing membranes used for long term use.

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.

In this work, methylmethacrylate, MMA was polymerized by ATRP method to obtain low molecular weight living polymers. The initiator was p-toluenesulfonylchloride and catalyst ligand complex system were CuCl-4,4&rsquo / dimethyl 2,2&rsquo / bipyridine. Polymers with controlled molecular weight were obtained. The polymer chains were shown by NMR investigation to be mostly syndiotactic. The molecular weight and molecular weight distribution of some polymer samples were measured by GPC method. The K and a constants in [h]=K Ma equation were measured as 9.13x10-5 and 0.74, respectively. FT-IR and X-Ray results showed regularity in polymer chains. The molecular weight-Tg relations were verified from results of molecular weight-DSC results.

Submitted by MARIA BEATRIZ ALVES AFONSO null (mbaafonso@hotmail.com) on 2017-06-12T21:05:33Z No. of bitstreams: 1 Dissertação_ Maria Beatriz Alves Afonso.pdf: 2111821 bytes, checksum: 42668991264b1d02752d3be1fc9cc953 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-13T17:19:35Z (GMT) No. of bitstreams: 1 afonso_mba_me_sjrp.pdf: 2111821 bytes, checksum: 42668991264b1d02752d3be1fc9cc953 (MD5) / Made available in DSpace on 2017-06-13T17:19:35Z (GMT). No. of bitstreams: 1 afonso_mba_me_sjrp.pdf: 2111821 bytes, checksum: 42668991264b1d02752d3be1fc9cc953 (MD5) Previous issue date: 2017-05-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A investigação de sistemas catalíticos duais capazes de mediar as reações de polimerização por abertura de anel via metátese (ROMP) e de polimerização radicalar por transferência de átomo (ATRP) simultaneamente é de grande interesse e importância na obtenção de novos materiais com potencial de aplicação. Neste estudo, novos complexos de rutênio(II) coordenados a diferentes bases de Schiff derivadas de cicloalquilaminas (ciclopentil 1a, cicloexil 1b, cicloheptil 1c e ciclooctil 1d) foram sintetizados: [RuCl(CyPen-Salen)(PPh3)2] 2a, [RuCl(CyHex-Salen)(PPh3)2] 2b, [RuCl(CyHep-Salen)(PPh3)2] 2c e [RuCl(CyOct-Salen)(PPh3)2] 2d. As bases de Schiff e seus respectivos complexos de rutênio foram caracterizados por FTIR, UV-Vis, RMN e voltametria cíclica. Os complexos planejados foram avaliados como precursores catalíticos em reações de ROMP de norborneno (NBE) e em reações de ATRP de metacrilato de metila (MMA). As sínteses de polinorborneno (poliNBE) via ROMP com os complexos 2a-d como pré-catalisadores foram avaliadas sob diferentes condições de reação ([HCl]/[Ru], [EDA]/[Ru], [NBE]/[Ru] e temperatura). Os melhores rendimentos de poliNBE foram obtidos a 50 °C com razão molar [NBE]/[HCl]/[Ru] = 5000/25/1 na presença de 5 µL de EDA por 60 minutos. A polimerização de MMA via ATRP foi conduzida usando os complexos 2a-d na presença de etil-α-bromoisobutirato (EBiB) como iniciador. Os testes catalíticos foram avaliados em função do tempo de reação usando a razão molar [MMA]/[EBiB]/[Ru] = 1000/2/1. Todos os experimentos via ATRP foram conduzidos à 85 °C. A correlação linear do ln([MMA]0/[MMA]) em função do tempo na ATRP de MMA mediada pelos complexos 2a-d indica que a concentração de radicais permanece constante durante a polimerização. As massas moleculares aumentaram linearmente com a conversão com a diminuição dos valores de IPD, no entanto, as massas moleculares experimentais foram maiores do que as massas moleculares teóricas. / The investigation of dual catalytic systems able to mediate simultaneously ring-opening metathesis polymerization (ROMP) and atom-transfer radical polymerization (ATRP) reactions is of great interest and importance in obtaining new materials with potential for application. In the study, ruthenium(II) complexes of Schiff base derived from cycloalkylamines (cycloalkyl = cyclopentyl 1a, cyclohexyl 1b, cycloheptyl 1c and cyclooctyl) 1d were synthesized: [RuCl(CyPen-Salen)(PPh3)2] 2a, [RuCl(CyHex-Salen)(PPh3)2] 2b, [RuCl(CyHep-Salen)(PPh3)2] 2c and [RuCl(CyOct-Salen)(PPh3)2] 2d. The Schiff bases 1a-d and their respective RuII complexes 2a-d were characterized by FTIR, UV-Vis, NMR, and cyclic voltammetry. The complexes 2a-d were evaluated as catalytic precursors for ROMP of norbornene (NBE) and for ATRP of methyl methacrylate (MMA). The syntheses of polynorbornene (polyNBE) via ROMP with complexes 2a-d as pre-catalysts were evaluated under different reaction conditions ([HCl]/[Ru], [EDA]/[Ru], [NBE]/[Ru], and temperature). The highest yields of polyNBE were obtained with [NBE]/[HCl]/[Ru] = 5000/25/1 molar ratio in the presence of 5 µL of EDA for 60 minutes at 50 °C. MMA polymerization via ATRP was conducted using the complexes 2a-d in the presence of ethyl-α-bromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 85 °C. The linear correlation of ln([MMA]0/[MMA]) and time clearly indicates that the concentration of radicals remains constant during the polymerization and that the ATRP of MMA mediated by 2a-d proceeds in a controlled manner. Molecular weights increased linearly with conversion, however, the experimental molecular weights were higher than the theoretical ones.

The past few years have seen a rapid expansion in interest in the characterization of the entire complement of proteins, or proteome. Micro total analysis systems (μTAS) are an emerging promising method, offering rapid, sensitive and low sample consumption separations. I have demonstrated microchip capillary electrophoresis (CE) devices made of CaF2. New methods have been developed for micromachining enclosed capillaries in CaF2. CE analysis of fluorescently labeled amino acids was used to illustrate bioanalytical applications of these microdevices. Initial on-chip infrared spectroscopy results for qualitative analyte identification were achieved in microfluidic CaF2 channels. I have also shown the evaluation of poly(methylmethacrylate) (PMMA) and thermoset polyester (TPE) microchips for use in protein profiling. To improve separation efficiency and reduce protein adsorption, dynamic coating and poly(ethylene glycol) (PEG) grafting using atom transfer radical polymerization (ATRP) have been used in PMMA microdevices. Proteins, peptides and protein digests have been separated electrophoretically in these PMMA microchips. My results demonstrate that PMMA microdevices should be well suited as microfluidic systems for high performance separations of complex biological mixtures. In-channel ATRP has been developed for the surface modification of TPE microdevices. Characterization indicates that PEG-modified microchannels have much lower and more pH-stable electroosmotic flow, more hydrophilic surfaces and reduced nonspecific protein adsorption. CE of amino acid and peptide mixtures in these PEG-modified TPE microchips had good reproducibility. Phosducin-like protein and phosphorylated phosducin-like protein were also separated to measure the phosphorylation efficiency. My results show that PEG-grafted TPE microchips have broad potential application in biomolecular analysis. Cancer marker analysis is important for medical research and applications. I report a method that can covalently attach appropriately oriented antibodies of interest on monolith surfaces. To reduce nonspecific adsorption, protein solutions were used to effectively block the monolith surface. Selective preconcentration and elution of human chorionic gonadotropin have been performed in my affinity columns, demonstrating that this type of system should have promising applications in cancer marker detection.

Nanoparticles promise many interesting applications because of their exceptional chemical and physical properties. Therefore nanoparticles offer a pathway for the fabrication of new functional, smart materials. Since the primary particle strongly tends to strong agglomeration, and since the surface of nanoparticles is often not compatible with polymers, it is not possible to disperse single particles homogeneously in a polymer melt. Formations of agglomerates are responsible for strong differences in concentration of the nanoparticles in the material matrix and therefore impede a homogeneous property profile. Furthermore properties of compounds are not only determined by single components, but considerably by the interface between these single components. Hence, a strong chemical and physical adhesion between the constituents is required. Thus, surface modification of nanoparticles is a crucial issue. This work focuses on the control of the particle/polymer interface in composite materials which has a thickness of some nanometers. This interface regulates the compatibility of the surface of the nanoparticles and their environment. This interface is also the place where the transmission of energy between nanoparticle and polymer occurs. The interlayer of this boundary surface should be occupied with functional “primer”-macromolecules that provide at least two types of functional groups: one species of functional group should assure the bonding of the primer to the surface of the nanoparticle, and the second type enables the compatibilizing to the matrix, and when indicated also the covalent adhesion to the ambient polymer system. The macromolecular scaffold of the primer permits the selective adjustment of important interface properties as elasticity, durability and the surface energy of the particle – matrix interface. Within this thesis hyperbranched polyethylene (PEI) imine was used as starting platform for “Quat-Primer Polymers” bearing a multitude of functional moieties in form of primary, secondary and tertiary amino groups. Chapter 2 gives a literature – review on hyperbranched polymers – with focus on PEI, stabilization of colloids by polymers, as well as polymer – “nanocomposites”. In Chapter 3 the reaction of PEI with glycidyltrimethylammonium chloride will be described to obtain hyperbranched polymers that consist of (i) the hyperbranched PEI scaffold, (ii) primary, secondary and tertiary amino groups that can be used for further modification reactions with amino-reactive compounds, and (iii) ammonium moieties that can adsorb to negatively charged surfaces. It will be shown that these Quat-Primer polymers have the ability to stabilize several nanoparticles in water to form aqueous dispersions and that they are capable to partially deagglomerate nanoparticles leading to smaller diameters of the particles in the dispersion. Additionally the reaction of hyperbranched polyethylene imine with glycidol will be described displaying a possibility to change the reactivity of the functional groups and exhibiting that also the generated hydroxyl groups generated by the ring-opening reaction of epoxides with PEI react with epoxide rings to form ether linkages. In Chapter 4 the synthesis of several amino-reactive ATRP initiators will be described and two methods to graft PMMA arms to “Quat-Primer polymers” presented in the previous chapter including the “grafting from” and the “grafting to” technique. These synthesized Quat-Primer polymers bearing ammonium moieties, as well as PMMA arms can be used to fabricate PMMA nanocomposites with homogeneously distributed nanoparticles. The developed method allow for grafting monomers that can be used in ATRP polymerization, including acrylates, acrylonitriles and styrenes, to hyperbranched polyethylene imine. Chapter 5 will display pathways to graft caprolactam derivatives to hyperbranched polyethylene imine to generate Quat-Primer polymers bearing ammonium moieties, as well as caprolactam rings. These quat-primer polymers can be used for the fabrication of PA-6 nanocomposites by dispersing nanoparticles in presence of these Quat-Primer polymers and subsequent polymerization.

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No description available.

This thesis investigates the effect of reaction media on the efficiency of grafting hydrophobic polymers from cellulose nanocrystals (CNCs) via surface-initiated atom transfer radical polymerization (SI-ATRP), with the goal of producing highly-modified CNCs for incorporation into latex-based pressure sensitive adhesives (PSAs). A latex is a dispersion of polymer particles in water made by emulsion polymerization; latexes are commonly used in paints, coatings, elastomers, inks/toners, household products, cosmetics, and adhesives. However, latex-based PSAs often underperform compared to their organic solvent-polymerized counterparts due to a lack of cohesive strength in the cast latex films. The environmental benefit of using latex-based PSAs synthesized in water is significant, but the development of strategies to improve their performance are required. CNCs are hydrophilic rod-shaped nanoparticles with high mechanical strength. Adding CNCs to latex-based PSAs has been shown to improve both adhesive (i.e., tack and peel strength) and cohesive (i.e., shear strength) properties and offers a degree of sustainability because CNCs are derived from natural cellulose sources such as wood pulp. However, their hydrophilicity, particularly relative to the hydrophobic polymers used in PSAs, has constrained CNCs to the continuous (i.e., water) phase of the latex. To improve CNC compatibility with the dispersed (i.e., polymer) phase and improve their distribution in cast latex films, hydrophobic polymers can be grafted from CNCs. However, CNCs with a high polymer graft density are required to ensure their compatibility with monomers/polymers during latex synthesis. To begin, grafting poly(butyl acrylate) (PBA) from CNCs using SI-ATRP in polar dimethylformamide (DMF) versus non-polar toluene was directly compared. The enhanced colloidal stability of initiator-modified CNCs in DMF led to improved accessibility to surface initiator groups during polymer grafting. As such, PBA-grafted CNCs produced in DMF had up to 30 times more grafted polymer chains than PBA-grafted CNCs produced in toluene. The PBA-grafted CNCs produced in DMF showed high contact angles when cast in a film and formed stable suspensions in toluene. This work highlights that optimizing CNC colloidal stability in a given solvent prior to polymer grafting is a more crucial consideration than solvent–polymer compatibility in the context of obtaining high graft densities and thus hydrophobic CNCs via SI-ATRP. The improved polymer grafting method in DMF was then used to produce PBA and poly(methyl methacrylate) (PMMA)-grafted CNCs at two polymer chain lengths. Polymer grafted CNCs were incorporated in situ during a seeded semi-batch emulsion polymerization to produce PBA latex nanocomposite PSAs. Viscosity measurements revealed significant differences between latexes prepared with CNCs versus polymer-grafted CNCs, with the lower viscosities of the latter suggesting their incorporation inside the polymer particles. When CNCs with short polymer grafts were introduced into PSAs at 1 wt. % loading, they exhibited comparable tack and improved peel strength compared to unmodified CNCs (and all properties improved relative to the base latex without any CNCs). This is attributed to their improved distribution throughout the PSA, the enhanced wettability of the substrate with the CNC containing latex, and the increased polymer chain mobility achieved based on the low molecular weight of the grafts. CNCs with long polymer grafts aggregated in the latex and did not improve PSA properties. PMMA-grafted CNCs slightly outperformed PBA-grafted CNCs likely due to the higher glass transition temperature of PMMA. These results provide insight into future optimization of more sustainable latex-based PSA formulations as well as new commercial CNC-latex products, where the presence of low molecular weight grafts on CNC surfaces could improve polymer mobility and tack and peel strength. / Thesis / Master of Applied Science (MASc) / When the adhesives used in tapes, labels or sticky notes are produced using water-based reactions, they normally underperform compared to conventional adhesives produced using toxic solvents. To improve such water-based adhesives, adding nanocellulose (tiny particles derived from wood pulp) during synthesis has been shown to be an asset. Nanocellulose can be chemically modified to improve its compatibility with adhesive ingredients, and thus change the role of nanocellulose during adhesive manufacturing. In this thesis, modified nanocelluloses were added to water-based adhesives to evaluate their effect on performance (i.e., strength and stickiness). It was found that the reaction conditions during nanocellulose modification were crucial for obtaining highly modified particles that are compatible with adhesive ingredients. This work aims to provide insight for future production of less environmentally taxing adhesives made in water and expand the use of nanocellulose in new commercial products.