Composite gels strength

Neoprenes. Of the synthetic latices, a type that can be processed similarly to natural mbber latex and is adaptable to dipped product manufacture, is neoprene (polychloroprene). Neoprene latices exhibit poor initial wet gel strength, particularly in coagulant dipped work, but the end products can be made with high gum tensile strength, oil and aUphatic solvent resistance, good aging properties, and flame resistance. There are several types of neoprene latex, available at moderately high (ca 50 wt %) and medium soHds content. Differences in composition between the types include the polymer s microstmcture, eg, gel or sol, the type of stablizer, and the total soHds content (Table 22). 

PS-60 Is an acetylated polysaccharide containing 3- 4.5% 0-acetyl groups which are readily removed by heating at ca. pH 10. The resultant deacetylated product has increased potential gel strength after heating. A deacetylation step is usually incorporated Into any recovery process. Native PS-60 also contains a considerable amount of insoluble debris which can be removed by centrifugation or filtration. A typical purification scheme is shown in Figure 2. There are three basic forms of PS-60 which differ with respect to composition and properties and have different potential applications. 

There have been many recent studies of composite gels made by irradiation of mixed solutions of polymers and increases in strength have been reported when compared to single polymer gels [46]. It would be expected that the properties of these disordered systems would primarily follow the water content. 

Fig. 7 Compositional dependence of the gel strength of Highvis/Laponite mixture gel (dotted line) and its regenerated gel.

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