Manganese dioxide compounds are preferred curing agents for Polysulphide resins used as sealants in industry. These are required to have consistent setting characteristics and the investigation was initiated to characterise a number of proffered compounds of this type an to establish criteria by which an informed choice could be made of an optimum curing ages for a specific set of conditions. Several different chemical and physical properties were examined and critical parameters were established. A compound - sodium birnessite- was identified as a significant agent in the determination of curing properties. It was synthesised and its curing properties alone and in combination with other manganese dioxide compounds was evaluated. In an effort to find a specific reaction which might be used to characterise manganese dioxide curing agents it was decided to examine the classical reaction between these compounds and potassium chlorate. A literature search revealed major contradictions in the reported conditions under which potassium chlorate undergoes thermal decomposition as result of which it was decided to study the decomposition of potassium chlorate alone and in the presence of manganese dioxide and other catalysts. During this investigation a hitherto unreported high temperature structural change in potassium chlorate at 341° C was identified. The existence of this reversible change was confirmed by Powder Diffraction X-Ray analysis and an orthorhombic (near tetragonal) more open structure was assigned to it. It is suggested that the rapid decomposition of potassium chlorate in the solid state presence of catalysts is related to this change to a more open structure.

The wet method of deep mixing constructs binder-treated soil columns by mixing a binder-water slurry with soft soil in-situ to improve the engineering properties of the soil. The strength of binder-treated soil is affected by characteristics of the in-situ soil and binder, mixing conditions, and curing conditions.The study presented herein aims to investigate the influences of curing time, curing temperature, mix design proportion, organic matter in the soil, and curing stress on the strength of cement-treated soil. Fabricated and natural soft soils were mixed with a cement-water slurry to mimic soil improved by the wet method of deep mixing. Laboratory-size samples were cured under various curing conditions and tested for unconfined compressive strength (UCS).The experimental test results showed that (1) a higher curing temperature and longer curing time generally increase the strength; (2) organic matter in cement-treated soil decrease and/or delay the strength development; and (3) curing stress affects the strength but its effect is influenced by drainage conditions. Based on the test results, strength-predicting correlations for cement-treated soil that account for various curing conditions and organic contents were proposed and validated.This research contributes to advancing the knowledge about the effects of strength-controlling factors of soil improved by cement and to improving the reliability of strength predictions with the proposed correlations. Therefore, the number of sample batches that need to be prepared and tested in a deep mixing project can be reduced, thereby saving the project's time and costs while achieving the target strength of the improved soil. / Doctor of Philosophy / The deep mixing method has gained popularity in the U.S. as a ground improvement technique since the late 1990s. This method involves blending the native soil that needs to be improved with a binder such as cement and/or lime. Two types of deep mixing methods are available, depending on how to add binder to the soil: the wet method injects a binder-water slurry, while the dry method uses a powder form of binder.The binder reacts with water and soil thereby enhancing the engineering properties of the soil. The strength of binder-treated soil is influenced by many factors: (1) characteristics of native soil and binder; (2) mixing conditions (e.g., the amount of binder added and mixing energy); and (3) curing conditions (e.g., curing time, temperature, and stress). In this dissertation, the effects of curing conditions and organic matter in the soil on the strength of cement-treated soil were investigated. Fabricated and natural soils were mixed with cement-water slurry to simulate the wet method, and the prepared samples were cured under various conditions. The strength results of cured samples showed that the characteristics of cement-treated soil are significantly affected by the amount of cement in the mixture, curing time, curing temperature, organic matter in soil, and curing stress. The test results were also used to derive correlations that account for the influences of curing conditions and organic matter.The findings and strength-predicting correlations presented in this research are expected to improve the knowledge about the deep mixing method and the reliability of strength prediction in a deep mixing project. This research, eventually, contributes to reducing time and cost of the project.

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The E-beam curable BMI resin systems and phenylethynyl terminated AFR-PEPA-4 oligomer together with an imide model compound N-phenyl-[4-(phenylethynyl) phthalimide] were synthesized and characterized. E-beam exposure cannot propagate the polymerization of BMI system until the temperature goes up to 100oC. However, a small amount of oligomers may be generated from solid-state cure reaction under low E-beam intensity radiation. Higher intensity E-beam at 40 kGy per pass can give above 75% reaction conversion of BMI with thermal cure mechanism involved. NVP is a good reactive diluent for BMI resin. The cure extents of BMI/NVP increase with the increase of the dosage and applied dosage per pass. The reaction rate is much higher at the beginning of the E-beam cure and slows down after 2 dose passes due to diffusion control. Free radical initiator dicumyl peroxide can accelerate the reaction rate at the beginning of E-beam cure reaction but doesn’t affect final cure conversion very much. According to the results from FT-IR, 200 kGy total dosage E- beam exposure at 10 kGy per pass can give 70% reaction conversion of BMI/NVP with the temperature rise no more than 50oC. The product has a Tg of 180oC. The predicted ultimate Tg of cured AFR-PEPA-4 polyimide is found to be 437.2oC by simulation of DSC Tg as a function of cure. The activation energy of thermal cure reaction of AFR-PEPA-4 oligomer is 142.6 ± 10.0 kJ/mol with the kinetic order of 1 when the reaction conversion is less than 80%. The kinetics analysis of the thermal cure of N-phenyl-[4-(phenylethynyl) phthalimide] was determined by FT-IR spectroscopy by following the absorbance of the phenylethynyl triple bond and conjugated bonds. The thermal crosslinking of N-phenyl-[4-(phenylethynyl) phthalimide] through phenylethynyl addition reaction has a reaction order of 0.95 and an activation energy of 173.5 ± 8.2 kJ/mol. The conjugated bond addition reactions have a lower reaction order of 0.94 and lower activation energy (102.7 ± 15.9 kJ/mol). The cure reaction of N-phenyl-[4-(phenylethynyl) phthalimide] can be described as a fast first-order reaction stage followed by a slow second stage that is kinetically controlled by diffusion.

Ionomers bearing reactive ion-pair functionality are a novel class of materials that have been prepared. The N-alkylation of N-vinylimidazole by poly(isobutylene-co-isoprene) produced the reactive ionomer product in good yield, through a solvent-borne process. Solvent-free conditions can also be used to produce reactive ionomers by the N-alkylation of N-vinylimidazole by poly(isobutylene-co-para-methylstyrene). Characterization of these derivatives was carried out with the assistance of model compounds, and showed excellent agreement with 1H NMR spectra. These reactive ionomers readily crosslink with peroxide at elevated temperatures and in the absence of peroxide they have excellent thermal stability. The amount of crosslinking can be altered based on the vinyl content of the material, to target various applications. N-alkylation of N-vinylimidazole can be carried out concurrently with a non-reactive N-alkylimidazole to achieve desired vinyl contents and tailor the physical properties of these materials. These materials contain both ionic and covalent crosslink networks, and this hybrid network structure provides these materials with unique crosslink structures and stress relaxation properties. Conventional rubber fillers are compatible with these novel reactive ionomers. Carbon black and precipitated silica have no adverse effects on the peroxide crosslinking of the elastomers and a constant peroxide loading can be used regardless of the filler loading. Payne analysis shows good filler dispersion at low filler loading; however, there is some evidence of reticulate filler network formation at high filler loadings. / Thesis (Master, Chemical Engineering) -- Queen's University, 2012-03-31 21:12:46.618

Thesis (M.S.)--Rochester Institute of Technology, 1993. / Typescript. Includes bibliographical references (leaves 58-60).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 169-172). Also available via the Internet.

The purpose of this work has been to generate a method by which an automobile tire manufacturer can optimally allocate its weekly production ticket to its automatic tire-curing presses. The problem is of interest for the reason that the value of the objective function is markedly affected by the relative locations of tires amongst themselves. This consideration has negated the possibility of a solution being effected by the application of an algorithm for the classical linear assignment problem. In this work the problem has been formulated and solved as a quadratic assignment problem. The logic of this method of solution has been programmed and subsequently used to solve example problems, the results of which are extremely encouraging. / Thesis / Master of Engineering (MEngr)