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A photopolymer or light-activated resin is a polymer that changes its properties when exposed to light, often in the ultraviolet or visible region of the electromagnetic spectrum. [1] These changes are often manifested structurally, for example hardening of the material occurs as a result of cross-linking when exposed to light.
Cationic polymerization is used in the curing of epoxy resins in the presence of UV in the industry. [16] Light energy from UV breaks apart photoinitiaters, forming an acidic solution which then donates a proton to the polymer. The monomers then attach themselves to the polymer, forming longer and longer chains leading to a cross-linked network.
UV stabilizers in plastics usually act by absorbing the UV radiation preferentially, and dissipating the energy as low-level heat. The chemicals used are similar to those in sunscreen products, which protect skin from UV attack. They are used frequently in plastics, including cosmetics and films. Different UV stabilizers are utilized depending ...
In chemistry, a photoinitiator is a molecule that creates reactive species (free radicals, cations or anions) when exposed to radiation (UV or visible). Synthetic photoinitiators are key components in photopolymers (for example, photo-curable coatings, adhesives and dental restoratives).
This reduces the absorption of UV rays by the polymer matrix and hence reduces the rate of weathering. Phenolic benzotriazoles (e.g. UV-360, UV-328) and hydroxyphenyl-triazines (e.g. Bemotrizinol) are used to stabilise polycarbonates and acrylics, [25] oxanilides are used for polyamides and polyurethanes, while benzophenones are used for PVC.
Polyurethane foam made with an aromatic isocyanate, which has been exposed to UV light. Readily apparent is the discoloration that occurs over time. Custom-cast polyurethane objects. Polyurethane products have many uses. Over three quarters of the global consumption of polyurethane products is in the form of foams, with flexible and rigid types ...
Dental composites. Glass ionomer cement - composite resin spectrum of restorative materials used in dentistry. Towards the GIC end of the spectrum, there is increasing fluoride release and increasing acid-base content; towards the composite resin end of the spectrum, there is increasing light cure percentage and increased flexural strength.
PETA is part of a family of acrylates used in epoxy resin chemistry and ultraviolet cure of coatings. Similar monomers used are 1,6-hexanediol diacrylate and trimethylol propane triacrylate. It is a derivative of pentaerythritol [2] One of the key uses of the material is in polymeric synthesis where it can form micelles and block copolymers.