Epoxy Reactions, Cross Linkage

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EPOXY REACTIONS Cross-linkage and Reaction of an Epoxy Resin ABSTRACT In this experiment the polymerization reactions with epoxy resins are studied. Cross-linked and chain polymers are synthesized with the reaction of reactive oxirane structure in Dow D.E.R. 331 epoxy resin respectively with MDAP and piperazine. The physical differences of two polymers are observed and IR spectrometry of the piperazine and epoxy resin reaction is taken, characteristic epoxy peak and O-H peak transmittance changes which show the reaction progress were determined. INTRODUCTION Epoxy resins are chemicals that are resistant corrosion, have good mechanical and thermal properties, good electric insulating properties and low shrinkage upon curing. Epoxy resins are widely used in industry since 1946 as protective coatings, adhesives and used for structural applications though in structural applications they can be quite notch sensitive. Epoxy contain more than one epoxide group per molecule and they can react with myriads of substrates. The epoxide ring can especially react with alcohols, amines and carboxylic acids [1]. Liquid resins are converted into insoluble and infusible solids through oxirane reactions. The oxirane structure is referred as epoxy functionality. The resin used in the experiment has a functionality of two. Resins are usually prepared with the reactions of bisphenols –and generally commercially bisphenol A- with epichlorohydrin or glycidyl chloride. Epoxy resins are generally cured with primary/secondary polyamines, anhydrides, and polyamides. A cross-linked structure is produced; this network structure is the desired infusible, insoluble product [2]. EXPERIMENTAL Materials: Piperazine, Toluene, Dow -D.E.R. 331- (Epoxy Resin), MDAP –diamine-, triethylamine Reflux Set-Up( 2-neck round bottom flask, vigroux column, thermometer, heater, boiling chips) Glass Rod,

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