Cook, DJ, Morgan, DR, Sirivivatnanon, V & Chaplin, RP 1976, 'Differential thermal analysis of premix polymer cement materials', Cement and Concrete Research, vol. 6, no. 6, pp. 757-764.
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In this paper, the use of DTA thermograms, to examine the interaction between premix polymer systems and hydrating cement, are described. The thermograms indicate that the polymerisation method (i.e., thermal or irradiation) has little effect on the nature of the hydration products. It was also observed that polystyrene, polyvinyl acetate, polymethyl methacrylate and polyester-styrene, as premix components, react with the hydrating cement. Polystyrene and polyisoprene have no effect on the calcium hydroxide endotherm while polyacrylonitrile and polymethyl methacrylate have a slight effect. Polyvinyl acetate and polyester-styrene markedly reduce the calcium hydroxide endotherm and reduce the maturity of the paste. © 1976.
Cook, DJ, Morgan, DR, Sirivivatnanon, V & Chaplin, RP 1976, 'Premix copolymer cement materials', Cement and Concrete Research, vol. 6, no. 2, pp. 235-243.
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Studies to determine the influence of mixtures of monomers (and subsequently copolymers) on the behaviour of premix copolymer cement materials are described in this paper. Five system viz styreneacrylonitrile, styrene-vinyl acetate, methyl methacrylate - vinyl acetate, butyl methacrylate - methyl methacrylate and butyl acrylate - methyl methcrylate, were investigated. Setting time and hydration studies were carried out on premix cement pastes while compressive strength tests were carried out on premix mortars, to determine the influence of monomer volume, surfactants and polymerisation method. The results indicated, as has most of the work on premix systems, that the influence of the copolymers was to increase setting time, decrease the degree of hydration as measured by percentage of chemically combined water and decrease strength relative to that of specimens continuously moist cured. © 1976.
Waldron, KJ 1976, 'Elimination of the Branch Problem in Graphical Burmester Mechanism Synthesis for Four Finitely Separated Positions', Journal of Engineering for Industry, vol. 98, no. 1, pp. 176-182.
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A graphical construction is presented which, when used for Burmester mechanism synthesis for four finitely separated positions, enables the designer to avoid solutions which will not pass all design positions without being disconnected. The construction is applied to the circle point curve and locates all regions of that curve which give acceptable solutions. The procedure is simple, requiring only construction of circles and straight lines. It is also compatible with Modler’s technique for ensuring that the linkage passes the design positions in the desired order.
