The stability against coalescence of vegetable oil-in-water “food grade” emulsions in the presence of both surfactant and colloidal particles (hydrophilic silica) has been studied and compared to the stability of systems where only the surfactant or the colloidal particles act as the emulsifier. No attempt was made to stop the emulsions from creaming. Two types of surfactants were selected; those that have the ability to stabilise O/W emulsions on their own (O/W surfactants) and those that cannot (W/O surfactants). Tween 60 and Sodium Caseinate were selected as the O/W surfactants, monoolein and lecithin as the W/O surfactants. These mixed emulsifier systems were shown to induce long-term emulsion stability against coalescence, regardless of the surfactant type, via a synergistic “two-part” mechanism in which both the surfactant and colloidal particles components have specific functions. Nonetheless, the emulsion microstructure was proved to depend on the surfactant’s type and concentration: the use of O/W emulsifiers above a certain concentration induced a displacement of particles from the interface, while such a displacement was not observed using W/O emulsifiers. Further measurements of interfacial tension and contact angle showed that the level of adsorption of solid particles at the interface depended on the surfactant type and concentration.

The ability of waterborne coatings to adhere to polypropylene-based substrates is a challenge in the automotive industry. This thesis seeks to explore novel methods to improve the adhesion and provide coated substrates of an industrial standard. Two methods are explored, whereby a physical entanglement method is found to be unsuccessful but a chemical bonding method is found to give patentable results. It is found that the UV curing of carbene precursors as candidate adhesion promoters, gives an adhesive force which is comparable to the industrial state of the art method, flaming. Initially, the UV energy initiates CH insertion reactions, which covalently graft the adhesion promoter to the polypropylene surface. Secondly, the hydrophilic functional groups of the adhesion promoter adhere to the waterborne basecoat, thus optimal adhesion is achieved. Statistical modelling of the results reveals that the adhesive strength depends on the UV intensity, the adhesion promoter concentration and functional group type. To explore the industrial applicability, the safety and stability during storage and the aesthetics of the adhesion promoters were investigated. This research is the first step to developing a formulation that is able to replace the current flaming method.

Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Engineering, 2009. / "May, 2009." Title from electronic dissertation title page (viewed 11/27/2009) Advisor, Avraam I. Isayev; Committee members, James L. White, Erol Sancaktar, Kevin Kreider, Minel J. Braun; Department Chair, Sadhan C. Jana; Dean of the College, Stephen Cheng; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed Feb. 8, 2010). Additional advisors: J. Barry Andrews, Kathryn Brannon, Derrick R. Dean, Gregg M. Janowski, Mark L. Weaver. Includes bibliographical references (p. 158-161).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vii, 42 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 33-34).

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No description available.

Multi-component crystallisation is investigated as a route to controlling crystalline forms of selected materials that possess pharmaceutical properties. This includes investigating the use of co-crystallisation methodology to selectively crystallise metastable polymorphs and solvated forms of these materials. This differs from the conventional use of co-crystallisation, as the aim of this aspect of the investigation is not to obtain a molecular complex of the two components, but instead for them to crystallise independently, while one component perturbs the solution environment to direct the crystallisation of the second component towards a different, often metastable, polymorph (or solvate). This co-crystallisation methodology is used as a route to crystallising new or elusive polymorphs (or solvates) of the active pharmaceutical ingredients paracetamol, piroxicam, gallic acid monohydrate and piracetam. It is also demonstrated that the use of this method can lead to crystal forms with otherwise unobtainable structural features. Co-crystallisation is also investigated as a route to controlling the ionisation state of piroxicam in the formation of molecular complexes. Molecular complexes were formed with a number of mono-substituted benzoic acids as well as with nitrogen-heterocycles and strong acids. In the molecular complexes formed, piroxicam was found to adopt the non-ionised, zwitterionic, anionic or cationic form, depending on the co-former used. Attempts are made to rationalise the occurrence of each ionisation state by consideration of the relative pKa values of piroxicam and the co-formers. The hydrogen bonded supramolecular synthons in these molecular complexes are also investigated. Co-crystallisation is also used as a route to obtaining molecular complexes of paracetamol and its derivative, 4-acetamidobenzoic acid, with nitrogen-heterocycles as co-formers. Molecular complexes of the two, with similar co-formers, are compared in terms of their hydrogen bonded supramolecular synthons. Despite having otherwise similar structural features, the phenolic hydroxyl group in paracetamol and carboxylic acid group in 4-acetamidobenzoic acid result in the formation of very different synthons and in some cases different component ratios. The susceptibility of 4-acetamidobenzoic acid to deprotonation is found to play a major role in the differences observed. Molecular complexes of paracetamol with co-formers containing multiple carboxylic acid groups are also investigated, with a view towards further crystal engineering approaches for molecular complexes of paracetamol. Piracetam complexes with carboxylic acids are investigated in a similar manner. The potential for transfer of a range of these multi-component crystallisations into a non-evaporative environment, with a view to implementing continuous crystallisation approaches, is also investigated. This transfer is found to be challenging for the systems investigated.

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With the increase in usage of engineering ceramics, a new industrial standard is required in order to evaluate its properties and to perform a fair and just trade. The thesis investigates the faults and omissions of existing work and judges today's requirements thereby constructing a framework with which today's and future standards in flexure testing can be based. The draft standard presented in this thesis covers the three major testing methods for determining the biaxial flexural strength (modulus of rupture) of engineering ceramics. The ring-on-ring, ball-on-ring, and 4-Ball test fixtures were all adopted as standard, since it is known that each of these systems is suited for a particular application and each has different advantages and disadvantages. The three major biaxial test methods prescribed in this draft standard have been devised so that more consistent and accurate test results can be obtained. However, the uncertainty of measurement in flexure testing always exists and needs to be estimated. The estimation of uncertainty in flexure testing in this study is based on the methodology provided in the ISO Guide to the expression of uncertainty in measurement. The results of the estimation showed that the uncertainty in measurement for the biaxial flexure test standard proposed in this thesis is very low compared to the inherent variability of the strength of ceramic materials. It was also found that the applied load, thickness of the disc plate, and random effects are the three major components contributing to the overall uncertainty. The total uncertainty of measurement in biaxial flexure testing can be significantly minimised by the reduction of the uncertainty contributed from these components, especially from random effects.