Model Nitrile rubber

Widenor, W. M. "Model Fire Tests on Polyphosphazene Rubber and Polyvinylchloride (PVC)/Nitrile Rubber Foams"... 

Lewis and co-workers (42) developed improved powder coatings with nitrile rubber-modification of an appropriate epoxy base (solid resin admixture) cured with an imidazoline-accelerated modified phenolic type hardener. Model coatings ground to 55 pm particle size, electrostatically applied to metals, cured 10 170°C, gave excellent therraocycling results as well as retained resistance to solvent attack. Elastomer-modified epoxy powder coatings have been covered extensively by Gelbel, Romanchick and Sohn in Chapter 5 of this volume. 

The results of searches of these two chemical classes matched by polymer are presented in Table II. Three candidate polymers (natural rubber, neoprene, and nitrile) were found with 15 models giving acceptable test data. 

An estimation of ZnCFO efficiency as vulcanization active component was carried out in modelling unfilled elastomeric compositions on the basis of isoprene, butadiene-nitrile, chloroprene and butyl rubbers of sulphur, thiuram, peroxide, metaloxide and resin vulcanization systems. 

Figure 7. Cure curves of vulcanization process of modeling unfilled elastomeric compositions on the basis of nitrile-butadiene rubber at 155°C with various vulcanization systems.

Numata and Kinjo (52) have shown rubber-modified isocyanurate-oxazolidone resins may be effectively modified with carboxyl-reactive nitrile liquids. The viscoelastic behavior of models using a polyglycidyl ether of phenol-formaldehyde novolac resin and di-phenylmethane-4,4 -diisocyanate is discussed. Such resins have suggested utility in thin films as electrical varnishes. 

The predictions of both models were then compared with measurements of the temperature variation of storage and loss moduli for a film made from a blend of polyvinyl chloride and nitrile butadiene rubber (Figure 8.10). It is seen that the... 

Figure 8.10 Temperature dependence of storage and loss moduli for a polyvinyl chloride-nitrile bidadiere rubber film bonded in parallel to a polyvinyl chloride film. Takayanagi model type (a) gives better fit to experiment. (Reproduced with permission fi om Takayanagi, Mem. Fac. Eng. Kyushu Univ., 23, 41 (1963))...

Block copol3nners form a new class of molecular composite materials by the phase separation of incompatible hard and soft segments which form their macro-molecular structure. Thermoplastic elastomers where the soft segments form the continuous phase have been extensively investigated by means of an adsorption-interdiffusion (A-I) model for the interfacial phase which bonds the hard and soft phases. The molecular structure and rheological activity of the interfacial phase in thermoplastic elastomer block copolymers is shown to play a dominant role in nonlinear viscoelastic response, mechanical hysteresis and energy absorption. Creation of elastomeric microphases in epoxy structural adhesives has been recently identified with in situ block copol3nnerization between carboxy terminated nitrile (CTBN) rubber and the diepoxide. 

Examples of nanocomposites that fit the tortuous path model relatively well include work by Shah et al. [2] with low-density polyethylene (LDPE) and ionomer, and by Gatos and Karger-Kocsis [3] with a nanocomposite of nitrile butyl rubber (NBR) and organofluorohectorite... 

One of the drawbacks to solvent-based adhesives based on rigid polymers is the shrinkage that results when the solvent evaporates. This can set up stresses that weaken the joint. An example of this type of adhesive is the familiar model airplane cement, basically a cellulose nitrate solution, with perhaps some plasticizer. Rubber cements, of course, maintain their flexibility, but cannot support as great a stress. Commercial rubber cements are based on natural, SBR oly(butadiene-co-styrene)), nitrile (poly(butadiene-co-acrylonitriIe)), chloro-prene (poIy(2-chlorobutadiene)), and reclaimed (devulcanized) rubbers. Examples are household rubber cement and Pliobond . Rubber cements may also... 

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