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RET Site for Polymer Engineering Research and Workforce Development
School of Polymers and High Performance Materials
University of Southern Mississippi
Research Publications:
Effect of Hydrogen Bonding on Tg and Free Volume Characteristics of EVOH Copolymers
Jamie Morrison, Glenn Dale, Grace Chigwada, and Sergei Nazarenko
Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) (2008), 49(1), 468-469.
Ethylene vinyl alcohol copolymers (EVOH) are one of the most important polymers used in the food packaging industry. EVOH is an excellent gas barrier. The hydroxyl groups in EVOH provide sites for hydrogen bonding. The hydroxyl groups in the copolymer have the ability to hydrogen bond with each other and the degree of hydrogen bonding can be controlled by varying ethylene and vinyl alcohol ratios in the copolymer.
Hydrogen bonds affect various properties such as density, solubility, gas permeability, glass transition temperature, and thermal stability. Currently, EVOH is commercially available up to 48 mole percentage of ethylene. EVOH copolymers with higher mole percentages of ethylene were synthesized in the lab by hydrolysis of ethylene vinyl acetate (EVA). In this work, EVOHX copolymers (where X represents mol % ethylene in the copolymer) were studied and the effect of hydrogen bonding on thermal, density and free volume properties were investigated.
Stimuli-Responsive Phospholipid Stabilized Poly(Ethoxyethyl Methacrylate-co-N-Isopropylacrylamide) (PEEMA-co-PNIPAm) Colloidal Dispersions and Their Films
Shelley Huskey, Amy Rutland, Laura G. Kolibal, and Marek W. Urban
Abstracts of Papers, 235th ACS National Meeting, New Orleans, LA, United States, April 6-10, 2008
The use of bioactive species in the synthesis of colloidal dispersions resulting in the development of a new generation of colloidal shapes has led to unique film properties that exhibit stimuli-responsive properties. These studies explored the synthesis of poly(ethoxyethyl methacrylate-co-n-isopropylacrylamide) (PEEMA-co-PNIPAm) copolymer utilizing three different copolymer composition ratios. All were prepared in the presence of either 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DCPC) or 1,2-dilauryl-sn-glycero-3-phosphocholine (DLPC) phospholipids with sodium dioctyl sulfosuccinate (SDOSS) as a co-surfactant. Using the combination of phospholipid concentration and copolymer composition, solution morphology can be controlled. High concentrations of NIPAm facilitated spherical PEEMA-co-PNIPAm particles in the presence of DLPC and DCPC stabilizing species. However, lower NIPAm concentration levels in combination with DCPC phospholipid enabled the creation of spherical and tubular entities. The copolymer solutions exhibit lower critical solution temperatures (LCST) which change as a function of copolymer composition. Also, copolymer composition directly effects zeta potential as a function of temperature. Spectroscopic analysis of the film-air (FA) and film-substrate (FS) interfaces revealed that during film formation, mobility of surfactants was inhibited by the presence of DCPC phospholipid. This behavior was attributed to the crosslinking of acetylenic groups in DCPC tails.
Miscibility of Solution Blended Films Containing Substituted Polyphenylenes and Polyphenylsulfones
Paul J. Jones, Rhonda Robertson, Crystal Smith, and Sarah E. Morgan
Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) (2008), 49(1), 523-524
Films containing copolymers of benzoyl-1,4-phenylene and 1,3-phenylene (SRPs) and polyphenylsulfone (PPSU) were formed using solution blending techniques. The films appeared optically transparent indicating that they are amorphous and exhibit some degree of miscibility. The effect of polymer architecture on miscibility was observed by solution blending copolymers with different compositions with PPSU. Miscibility of the systems was assessed using differential scanning calorimetry (DSC) to measure the thermal relaxation behavior of the pure and blended films. Results from DSC were compared to those predicted by the Fox equation.
Investigating the molecular basis of the rheology of polyelectrolyte microgels
Nicole McWright, Stephen Foster, Robert Y. Lochhead
Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) (2008), 49(1), 505.
The rheological evaluation and molecular interpretation of microgel rheology modifying systems are assisted by scaling theories have been developed to explain the role of hydrophobic ‘multistickers‘on the formation of gel networks by polyelectrolytes. We have adopted this rheological approach to gain insight into microgel sizes and to assess the level of interaction between the microgels. We have applied these theories in our
investigation of the interactions of polyelectrolyte microgels with aqueous film formers. Plots of reduced specific viscosity against polymer concentration for microgel rheology modifiers and hydrophobically-modified microgel rheology allow us to gain insight into the molecular behavior.
Investigating the interaction between polyelectrolyte microgels and water soluble film-formers by solubility parameter matching and measurement of phase behavior.
Lisa Fike, Ethan Boothe, Robert Y. Lochhead
Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) (2008), 49(1), 503-504.
The Hansen- Hoy theory of solubility parameters predicts that polymers will be compatible when all three components of the solubility parameter are matched. The three components are the cohesive energy densities due to dispersion forces, dipole-dipole interaction and hydrogen bonding respectively. Polyelectrolyte microgel rheology modifiers are extremely high molecular weight polymers and film-forming polymers are preferably linear or lightly branched. It is understood that higher molecular weights lead to lower miscibility between two polymer species and this is attributed to the lower configurational entropy of higher molecular weight polymers. However, the commercial application of these polymers requires that microgel rheology modifiers should be combined with film-formers in the same composition. It was of interest, therefore to investigate the compatibility of microgel rheology modifiers with typical aqueous-phase film-formers.
ROOM TEMPERATURE CURE EPOXY RESIN SYSTEMS
Olivia D. Brooks, Toby Richey, Samuel J. Tucker, Matthew Jackson, and Jeffrey S. Wiggins
Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) (2008), 49(1), 578.
Epoxy resins have been found to form hardened materials that have high flexibility and toughness making them useful for incorporation into fiber-reinforced composites. Recent papers show a direct correlation between ultimate properties of composites and resin/curative structure. In this project, a variety of aliphatic amine geometries (Figure 1) have been studied as curatives for a common aerospace epoxy resin, diglycidal ether of bisphenol A (DGEBA).
Figure 1
Vegetable Oil Macromonomer Synthesis and Waterborne Industrial Coatings
Glenn Dale, Jamie Morrison, David E. Delatte, Lori Howell, and James W. Rawlins,
J. Mississippi Academy of Sciences, Vol. 52, No. 1, 2007
Vegetable oils are triglyceride esters of fatty acids extracted as a raw material precursors from plants. Newly developed vegetable oil derivatives, termed vegetable oil macromonomers (VOMMs), have been designed and synthesized for use as comonomers in emulsion polymerization. VOMMs are being incorporated and developed for environmentally responsible, decorative, and protective coatings that do not require the use of cosolvents for efficient film formation. However, these VOMMs possess limited hydrolytic resistance as they contain labile ester groups, inherently susceptible to hydrolysis. Ester-free VOMMs were designed to achieve improved hydrolytic resistance. Several new reaction methodologies were conducted at various temperatures and the progress was monitored continuously via infrared spectroscopy. Meanwhile, industrial coatings were formulated using commercial latexes to serve as controls for evaluating VOMM-based emulsions in industrial coating applications. Three styrene-acrylic latexes and two alkyd dispersions were formulated into industrial coatings in combination with hexamethoxymethylmelamine crosslinker and evaluated via ASTM test methods.
Investigating the Effect of Sodium Chloride Concentration on Complex Coacervate Formation within a Concentrated Regime
Lisa Fike, Nicole McWright, and Robert Lochhead
J. Mississippi Academy of Sciences, Vol. 52, No. 1, 2007
Shampoos comprise amphipathic molecules called surfactants that self assemble into nano-scale micelles. The micelles are responsible for the cleaning action of shampoos. In conditioning shampoos, polymers interact with the surfactants. The dilution of shampoo while washing hair causes the cationic polymer and the anionic surfactant to form complex coacervates that can phase separate from the solution and, during rinsing, this polymer-surfactant complex is deposited on the hair as a conditioner. There are many possible self-assembled structures that can form from the surfactants and the polymers, and the shampoo formulator has to find the best formula. High-through-put screening allows the examination of hundreds of compositions each day. Thus, our high-throughput method using a liquid handler allows approximately 200 different concentrations to be performed in about 45 minutes. In our research, Polyquaternium 10 (JR 30M) was used as the cationic polymer and sodium lauryl ether sulfate (SLES) as the anionic surfactant. Sodium chloride (NaCl) is added to shampoos to increase the viscosity, but salts can also influence the micelle structure, the poly ion conformation and the nature of the coacervate. Our motivation in doing this experiment was to investigate how sodium chloride affects this interactive system. Our results show that as the concentration of NaCl increased, the amount of coacervate formed decreased in the ‘ion-exchange’ region but increased in the large micelle region.
Colloidal Dispersion of Poly-(methyl methacrlate/n-buty acrylate)
Amy Rutland, Shelley Huskey, Laura G. Kolibal, Anuradha Singh, and Marek W. Urban,
J. Mississippi Academy of Sciences, Vol. 52, No. 1, 2007
These studies focus on synthesis and film formation of colloidal dispersions containing stimuli-responsive components. In order to gain a fundamental understanding of these processes the influence of bio-active dispersing agents on colloidal film formation is examined. In this study, a copolymer of poly-(methyl methacrylate/n-butyl acrylate) was synthesized using an emulsion polymerization process. Utilizing sodium dioctyl sulfosuccinate (SDOSS) as surfactant, the effect of particle size and surfactant concentration was examined. These studies indicate that larger colloidal particles enhance the mobility of surfactant migration within the film matrix, which is attributed to decreased surfactant coverage around the larger colloidal particles and freer surfactant within the film matrix. The influence of bio-active phospholipids was also examined. These studies show that the presence of mixed micellar structures under various stimuli such as pH, ionic strength, and temperature lead to the controlled migration of individual dispersing agents to the film-air or film-substrate interfaces.
Investigation of the Performance of Coatings Formulated with the Reactive Diluent Tetra(2,7-octadienyl) titanate
Rhonda Robertson, Crystal Smith, Alp Alidedeoglu, Kevin Davis, James W. Rawlins, and Sarah E. Morgan
J. Mississippi Academy of Sciences, Vol. 52, No. 1, 2007
Solvents employed in coatings constitute volatile organic compounds (VOCs), and are the subject of environmental concern and legislation mandating reduction in their use. Consequently, significant research efforts are devoted to developing coatings with no or low solvent emissions. One method of reducing VOCs is to replace solvents with low viscosity reactive diluents designed to crosslink with the resin and form a part of the final film. A new reactive diluent, tetra(2,7-octadienyl) titanate, was synthesized through an ether exchange reaction between 2,7-octadienol and tetra(ethyl) titanate. The reaction was monitored via 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, high pressure liquid chromatography (HPLC), and Fourier transform infrared (FTIR) spectroscopy. The reactive diluent was blended at 10-30 weight percent with alkyd resins based on soybean oil and linseed oil. The coatings were applied on cold rolled steel panels, and evaluated for hardness, adhesion, impact strength, solvent resistance, viscosity, gloss, and chemical resistance properties. Coatings formulated with the reactive diluents were characterized by higher solids, faster drying, lower viscosity, lower VOCs, and better hardness relative to the controls. Adhesion and impact properties were somewhat reduced while other properties were equivalent to the controls.
Integrating Polymer Science into Middle/High School Curriculum
Toby Richey, Tasha Thames, Sarah E. Morgan, and Jeffrey S.Wiggins
J. Mississippi Academy of Sciences, Vol. 52, No. 1, 2007
A new and innovative way to introduce students to the fascinating world of polymers was a topic of study through the National Science Foundation sponsored RET (Research Experience for Teachers) at the University of Southern Mississippi. This was designed to broaden students’ limited knowledge of polymers beyond “plastics.” A variety of activities were presented to expand students’ perception of polymer science and instruct teachers on how to integrate this exciting field into any science curriculum. These activities were implemented by two Northeast Jones Middle/High School teachers: one a seventh grade science teacher and the other a ninth grade biology teacher. The students performed activities ranging from making nylon, slime, and shrinky dinks to evaluating super absorbent polymers in diapers. The benefit of these activities was to show students that polymers are a part of their every day life. As students’ knowledge of polymers increased it enabled them to take conceptual knowledge to a real-world understanding. Impact of the activities was assessed through surveys and content examinations.
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