Expoxy resins

Table B.8 Properties of CTBN-Expoxy Resin Compositions...

Bonding of thermoset plastic materials Due to their insolubility, thermoset plastic materials (e.g., items made of Bakelite, expoxy resin, boards with melamine urea coatings) are not bondable by surface dissolving with solvent-containing adhesives. 

Amidophosphazenes and aminophenoxyphosphazenes have been used as curing agents for expoxy resins and various thermal and mechanical properties have been measured. 

N3P3(OPh)50B3NjMe5. Heating of [NP(NH2)2Jn mixtures with urea gives cyclolinear polymers bridged by NH and NHC(0)NH units . Expoxy resins can be cured with a variety of phosphazenes i.e. 

A neat diacrylate ester of a low-molecular-weight bisphenol A expoxy resin... 

Encycl) with a binder (such as epoxy-polyamide, expoxy-anhydride, and polyurethane resins) and loading the resulting mixture into the annulus between the inner and outer parts of a cylindrical mold. After curing for 24hr, this cylindrical part of cartridge was attached to a noncombustible base(metallic or plastic), which served as an obturator... 

Syntactic foamed plastics (from the Greek ovvxa C, to put together) or spheroplastics are a special kind of gas filled polymeric material. They consist of a polymer matrix, called the binder, and a filler of hollow spherical particles, called microspheres, microcapsules, or microballoons, distributed within the binder. Expoxy and phenolic resins, polyesters, silicones, polyurethanes, and several other polymers and oligomers are used as binders, while the fillers have been made of glass, carbon, metal, ceramics, polymers, and resins. The foamed plastic is formed by the microcapsular method, i.e. the gas-filled particles are inserted into the polymer binder1,2). 

Expoxies [unmodified types of bisphenol A, higher functionalized resins, novolac epoxies, cycloaliphatic resins, heterocyclic resins one- and two-component systems curing at room temperature, at elevated temperatures, or by ultraviolet (UV) irradiation], used as mounting adhesives, coverings, and binders for laminates [1,2]... 

Examples of the resin components of expoxies are listed in Table 1. Several chemical substances can be used as hardeners for epoxies [5,6], The two main groups of cross-linking agents used in industry are two or more functionalized amines and anhydrides of carboxylic acids. Cross-linking with amines is possible at room temperature as well as at elevated temperatures, depending on the chemical structure of the amines (Table 2). Anhydrides of carboxylic acids react at elevated temperatures only. 

Modifiers that may also be reactive as curing agents (such as polysulphides, triphenyl phosphite, and some polyamides) can be used. Polysulphide polymers used on their own will react slowly with expoxies. One to three parts of an active catalytic amine or amine salt can be used to accelerate cure. Triphenyl phosphite reduces viscosity and lowers cost. Ratios up to 2 5 phr appear to have no severe effect on physical properties at room temperature. Although reactive with epoxy, triphenyl phosphite is not an effective curing agent by itself it needs also a polyfunctional amine. About 75% of the normal stoichiometric amount of amine gives optimum results when 2 5 phr triphenyl phosphite is used with a resin such asDER331. 

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