Silanes water soluble polymers

Silylated polyazamides (Si-PAA s) are water-soluble polymers. Therefore, they are absorbed more evenly from a one-phase aqueous medium to form a continuous fiber coating. Such a size provides excellent strand integrity and stiffness, resin compatibility and, most importantly, chemical reactivity with glass through pending silane functionality. 

Polymers that set by chemical reaction may react not only within the components of pre-polymer mixtures, but also with the substrate. This occurs principally with pre-polymers that are sensitive to water, such as isocyanates in polyurethanes and silanes. The chemical links can be deliberately created by using a reactive primer, e.g. a silane coupling agent. Many water-soluble polymers, e.g. poly(vinyl alcohol) and cellulose derivatives, may be expected to adhere more strongly and irreversibly because of the presence of reactive groups on degraded objects. 

Studies with silane-modified latexes suggest that low molecular weight, water-soluble polyelectrolytes deposit preferentially on a mineral surface to give a well-ordered layer of modifier between the latex polymer and the mineral surface. Physical... 

Mixtures of water-soluble silanes and typical latex polymers were checked as primers on glass for plaster adhesion. Conditions that allow the silane to remain in aqueous solution (Figure 1), or to deposit only on the latex particle surface are demonstrated by primer films that impart instant water-resistant adhesion of plaster... 

One disadvantage of all silica-based stationary phases is their instability against hydrolysis. At neutral pH and room temperature the saturation concentration of silicate in water amounts to lOOppm. Solubility increases with surface area, decreasing particle diameter drastically with pH above 7.5. This leads also to a reduction of the carbon content. Hydrolysis can be recognized during the use of columns by a loss in efficiency and/or loss of retention. Bulky silanes [32], polymer coating [33], or polymeric encapsulation [34] have been used in the preparation of bonded phases to reduce hydrolytic instability, but most of the RPs in use are prepared in the classical way, by surface silanization. Figure 2.3 schematically shows these different types of stationary phases. 

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