Sunday, June 7, 2009

Epoxy Resin From The Epoxidation of Olefin Compounds

Epoxy Resin From The Epoxidation of Olefin Compound: From the results of adhesion tests it would appear that in their present state of development the room temperature strength of the cycloapipharic epoxides generally, is lower than that of the glycidyl ether, even lower than that of those glycidyl system which incorporate a hardener that inevitable gives a brittle cured adhesive. The strength temperature relationship of the compounded illustrated above when cured with a 35/36 mixture of phthalic and tetrahydrophthalic anhydrides.

It is in the hot strength of these epoxides that most adhesives interest will probably develop. It has been reported that dicyclopentadiene dioxide cured with a maleic anhydride/polyol mixture gives the highest known service temperature properties, with a Deflection Temperature of 300oC. However, it will be noted that a Deflection Temperature of this order has been quoted for the glycidyl polyester of certain tris and tetrakis phenols.

The importance of the cycloaluphatic epoxides is undoubtedly lessened by the fact that their reactivity with amines is of a low order so that they are not ordinary cold curing. So far as hot curing is concerned, the conventional hardeners are anhydrides, and in some instances curing is faster than with bisphenol A glycidyl esthers. For some epoxides an anhydride/polyol mixture is recommended as being much faster than the anhydride alone. Among accelerators that are considered to be most efficient are stannous octoate and polyvalent metal salts of organic acidic compounds containing up to twenty four carbon atom.

Although butadiene is a major component in the synthesis of many cycloaliphatic epoxide, the aliphatic epoxides derived from butadiene itself have established themselves as a separate class, and it is therefore convenient to consider them separately. The simplest diepoxide is butadiene dioxide, a low viscosity liquid whose chief use is as a reactive diluent. Of more interest as adhesive are the epoxides of polygutadiene copolymers resin. One particular epoxide contains hydroxyl groups as well as epoxide groups and reactive double bonds. Such a polymer is capable of reacting with a number of substances and of curing with anhydride at room temperature, and with amines at elevated temperature, also of interest is its very rapid curing with anhydride/polyol hardeners at room temperature.