Unsaturated polyesters and acrylics

UNSATURATED POLYESTER AND ACRYLICS 213 Radiation curing polyesters and acrylics... 

Examples of unsaturated polyester and acrylic coatings are given below ... 

The parameters which influence the particle size of microgels have been studied during self-emulsifying, seeded emulsion copolymerization of an unsaturated polyester and butyl acrylate [134]. 

Osaka Organic Chemical will embark on volume production of a low-toxicity acrylic ester monomer with extremely low skin irritation, it is briefly reported. Principal applications are as a diluent monomer for UV and EB coating materials and inks, and as a modifier in unsaturated polyester resins, acrylic resins and PVC. OSAKA ORGANIC CHEMICAL INDUSTRIES CO.LTD. 

Manfredi, L. B., Rodriguez, E. S., Wladyka-Przybylak, M., and Vazquez, A. Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres, Polym. Degrad. Stabil. 2006, 91, 255-261. 

Structopendant Prepolymers. The reactive or functional groups are distributed along the prepolymer chain. Examples are the epoxies, unsaturated polyesters, and the thermoset acrylics. 

UV stabilizer particularly effective in styrenic polymers, PVC, unsaturated polyesters, polyurethanes, acrylic polymers and polycarbonates. 

Acrylics, unsaturated polyesters and other monomer-based adhesives containing ethy-lenic unsaturation, cure by formation of free peroxide radicals formed with transition metal ion donators such as cobalt, iron, copper and nickel. In engineering applications the presence of transition metals on surfaces sees them act as initiators by forming the free peroxide radicals from the added peroxide compound(s). The base monomers usually contain inhibitors such as phenols or other materials classed as peroxide stabilisers to... 

Unsaturated resins are usually mixtures of vinyl monomers and prepolymers, such as unsaturated polyesters, polyurethane acrylates, and ac-rylated epoxides of the bisphenol A type. Polymerization of styrene-based resins involves the formation of a three-dimensional network via the cross-linking of prepolymer chains by styrene radicals. These standard thermoset resins are therefore characterized by great hardness (Shore D over 80, DIN 53505, arbitrary scale 0-100 based on the penetration of a needle point in the tested material), do not melt, and are not soluble in organic solvents. 

Polymers are normally classified into four main architectural types linear (which includes rigid rod, flexible coil, cyclic, and polyrotaxane structures) branched (including random, regular comb-like, and star shaped) cross-linked (which includes the interpenetrating networks (IPNs)) and fairly recently the dendritic or hyperbranched polymers. I shall cover in some detail the first three types, but as we went to press very little DM work has been performed yet on the hyperbranched ones, which show some interesting properties. (Compared to linear polymers, solutions show a much lower viscosity and appear to be Newtonian rather than shear thinning [134].) Johansson [135] compares DM properties of some hyperbranched acrylates, alkyds. and unsaturated polyesters and notes that the properties of his cured resins so far are rather similar to conventional polyester systems. 

A trialkyl phosphite. It can be used in acrylics to iaqprove color euid molecular weight retention during processing. It also provides stability to nylon, unsaturated polyester, and PVC. When Weston TIOP phosphite is used in lubricants, it functions as a sulfur deactivator. It can also be used to improve antifriction and antiwear characteristics. 

Resins for exterior use (such as on window frames) need to be composed of materials known to have good weathering. Thus polyesters should not contain unsaturated acids, and acrylics should have a methyl methacrylate backbone rather than styrene. 

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