Acrylic plastics rheological properties

Degalan V 26 (Degussa, A.G., B.R.D.). This is a 90/10 (methyl methacrylate)-(butyl acrylate) copolymer. It mixes well with PVC and it does not affect its transparency, water absorption, and electrical properties. It is suitable to modify the rheological properties of impact-PVC. It shortens the plastication time of PVC mixtures and it improves their homogenization and the extrusion output. The addition of Degalan V 26 also improves the heat stability of PVC mixtures and increases the resistance of PVC-based products to heat distortion. 

The base polymer for this t5q>e of sealant exists in the form of an emulsion of micron- and submicron-sized partides of the polymer suspended in water. The base polymer formed by free radical polymerization may be a homopolymer of an acrylic monomer but is more likely to be a copolymer of a number of different monomers chosen to provide the correct balance of properties. The polymer latex has to be made more permanent and therefore a nonionic surfactant such as a nonyl phenol/ polyethylene oxide is added to help stabilize the emulsion. Other additives to the sealant formulation include plastid-zers, fillers, solvents, and silanes. A plasticizer is added to the formulation in order to improve upon or maintain the flexibility of the sealant. Solvents (usually a small amount) are added to improve the tooling of the sealant after it is applied. In addition, a solvent could be a material such as ethylene or propylene glycol which can improve the resistance of the packaged sealant to temperatures below freezing. The most widely used filler for this type of sealant is calcium carbonate. Silanes are often added to acrylics to improve the wet adhesion of the sealant to glass. Other additives include antimildew agents (for tub and tile applications) and clay for rheological control. 

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