Cross-linked epoxy amine polymers

Experimental restoration of inserted relaxation operators and testing of their prediction ability were made for cross-linked epoxy amine polymers from diglycide ether of bisphenol-A (DGEBA), which was solidillcated by stoichiometric amounts of 1-ami-nohexane (AH) and hexamethylenediamine (HMDA) in variation of their molar ratio from 0 to 2 with pitch 0.5. 

Information about the quantity of cross-linked polymers strain properties in their one or another physical state with known assessment of mechanical tensions is nesessary, for choice of the optimal cross-linked polymer matrix and high strength Dberglass products. In the network of search solutions of this problem was developed and conDrmed by experiments with cross-linked epoxy amine polymers, a new mathematical account of nanofragment cross-linked polymers pliability [1]. A pur-... 

Kortaberria, G., et al.. Curing of an Epoxy Resin Modified with Poly(Methylmethacrylate) Monitored by Simultaneous Dielectric/Near Infrared Spectroscopies. Europ. Polym, J., 2004.40 129-136. Mijovic, J., et al.. Interplay of Segmental and Normal Mode Dynamics in Polymer Networks Undergoing Chemical Cross-Linking. Epoxy/Amine-Terminated Linear and Stai PPO Eormnlations. Macmmolecules, 2003. 36 4589-4602. 

The calculated equilibrium network moduli of elasticity and experimental moduli measured in the rubbery state10,34) of different epoxy-amine networks show quantitative agreement. This means that the real structural nonuniformity of cross-linked epoxy-aromatic amine polymers exists only at the level of statistical deviations of network structure from the ideal one. A comparison of Ecalc and E p is shown in Fig. 4. 

Thermosetting latices contain functional groups, which can be used to cross-link the coating after film formation usually by heating. These polymers normally contain hydroxy monomers that can be cross-linked with materials such as water-soluble melamine derivatives, urea-formaldehyde, or phenolic resins. Alternatively, epoxy groups in the latex can be cross-linked with amines. 

Polymers containing methyne CH bonds, e.g. polypropylene (PP), or methylene CH bonds in the a position of a heteroatom, e.g. poly(methylene oxide) (POM), polyamides (PA) and amine cross-linked epoxy (ACE), are relatively unstable. 

Some commercial durable antistatic finishes have been Hsted in Table 3 (98). Early patents suggest that amino resins (qv) can impart both antisHp and antistatic properties to nylon, acryUc, and polyester fabrics. CycHc polyurethanes, water-soluble amine salts cross-linked with styrene, and water-soluble amine salts of sulfonated polystyrene have been claimed to confer durable antistatic protection. Later patents included dibydroxyethyl sulfone [2580-77-0] hydroxyalkylated cellulose or starch, poly(vinyl alcohol) [9002-86-2] cross-linked with dimethylolethylene urea, chlorotria2ine derivatives, and epoxy-based products. Other patents claim the use of various acryUc polymers and copolymers. Essentially, durable antistats are polyelectrolytes, and the majority of usehil products involve variations of cross-linked polyamines containing polyethoxy segments (92,99—101). 

The linear polymer formed is cured hy cross-linking either with an acid anhydride, which reacts with the -OH groups, or hy an amine, which opens the terminal epoxide rings. Cresols and other hisphenols are also used for producing epoxy resins. 

The epoxy prepolymer can be cured, that is, converted to a three-dimensional network, in several different ways. A trifunctional amine, such as NH2CH2-CH2NHCH2CH2NH2, can be mixed in and will extend the chain of the polymer and form cross-links by reacting with the oxide rings ... 

Another new and interesting polymer family, the Oxirons, are under development by Food Machinery and Chemical Corp. (13), These, too, are struoto-pendant prepolymers prepared from butadiene to which the epoxy functional group is introduced. Functionality may be of the epoxy or unsatiuration type. A typical prepolymer might be a material of a molecular weight of 1500. These systems are cross-linked with anhydrides, amines, and peroxides. 

Nonetheless, for the more than 50 years since the first publication in this field, NIPUs still do not have sufficiently broad application. This can be explained by certain features of these materials. Cyclic carbonate (CC) groups interact with aliphatic and cycloaliphatic polyamines at ambient temperatures more slowly than isocyanates with hydroxyl groups. The rate of this reaction is comparable to the rate of curing epoxy resins (ER) with amines. At the same time, the CCs react only with primary amino groups, in contrast to the ERs, which react with primary and with secondary amino groups. This results in a decrease in cross-linking density of the polymer network. 

Cationic epoxy resin based systems can be prepared by reacting quaternary amine salts with epoxy resins to introduce the cationic functions. The polymers can then be cross-linked with blocked isocyanates at reasonable baking temperatures (34. 35). 

Properties of the thermosetting polymers are controlled by the molecular composition and structure such as the stoichiometric ratio between the reagents, and the cross-link density of the network. Accordingly, fatigue crack propagation of an Epon 828 MDA epoxy has been examined [96] with respect to amine epoxy ratio and cross-link density. 

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