الفهرس 
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Abstract
Unsaturated polyester (UPE) resin is the most widely used
thermoset resin for polymeric composites , due to its relatively low price , ease of handling and its good balance of mec hanical , electrical and chemical properties . UPE resin is formed by the reaction of a polybasic acid and a polyhydric alcohol. The simplest process for production of UPE resin is by the reaction of mixture of maleic and phthalic anhydrides with propylene glycol that permits cross - linking with
· unsaturated monomers such as styrene, forming thermosetting plastics. UPE resin can be cured in few minutes simply by adding a peroxide catalyst. Curing takes place by addition reaction that involves the conversion of double bonds into
t single bonds , hence no by -product is released through this
reaction . There are many types of UPE resins such as general purpose, flexible ,resilient ,low shrinkage ,weather resistance, chemical resistance , and fire retardant polyester resins . UPE resins are used in the manufacture of a broad range of products , including boats ,building panels ,structure parts for automotive , air craft and appliances , fishing ---- etc .
Most UPE are not suitable as coatings because atmospheric
oxygen inhibits the crosslinking reaction . To circumvent
this difficulty a number of photochemical methods have been developed to cure UPE coatings .This photochemical method need. a photoinitiator to cataly;z; the photocrosslinking process ofUPE .This photoinitiator absorbs light and generate radicals or cations , which initiate polymerization or crosslinking
reaction • in this work investigating of the general purpose
1. UPE type ,by traditional method of curing (MEKP as catalyst and CoNap as accelerator). Also, studying the effect of different types of additives , such as styrene, aery lie acid,