Carboxylate butadiene-acrylonitrile

The effect of a variety of counterions in a carboxylated elastomer has been studied by Brown (19,20). Both divalent and monovalent metal counterions were investigated in a carboxylated butadiene-acrylonitrile copolymer system. The properties obtained depended on the particular... 

Chem. Descrip. Carboxylated butadiene-acrylonitrile copolymer Uses Provid good flexibility, soft hand for supported/unsupported gloves, textile coatings... 

Synonyms Acrylonitrile-butadiene copolymer, carboxyl-terminated Butadiene-acrylonitrile copolymer carboxylated Butadiene-acrylonitrile copolymer, carboxyl-terminated Carboxylated butadiene-acrylonitrile copolymer CTBN... 

Carboxylated butadiene-acrylonitrile copolymer. See Butadiene-acrylonitrile elastomer, carboxyl-terminated Carboxylated epoxy resin. See Epoxy resin, carboxylated... 

Carboxylated butadiene-acrylonitrile copolymer. See Butadiene-acrylonitrile elastomer, carboxyl-terminated 1-(2-Carboxylatoethyl)-4,5-dihydro-3-(2-hydroxyethyl)-2-isoheptadecyl-1H-imidazolium. See Sodium isostearoamphopropionate Carboxylic acid C4. See n-Butyric acid Carboxylic acid C5. See 2-Methylbutyric acid n-Valeric acid... 

Owston (14) has shown that fast curing, flexible industrial adhesives are capable of being prepared from solid butadiene/acrylonitrile or carboxylic butadiene/ acrylonitrile elastomers in combination with monomers and catalysts of choice. The systems discussed are at about 30% rubber level and provide 3,300-4,000 psl lap shear strengths with aluminum adherends utilizing hardening times as low as five minutes. 

Cements prepared from carboxylic butadiene-acrylonitrile copolymers blended with phenolic resins, like the analogous cements prepared with noncarboxylic butadiene-acrylonitrile copolymers, are adhesive agents for steel to rubber. Employed without curative agents, the carboxylic copolymers give better steel-to-rubber adhesion than the analogous noncarboxylic copolymers. Confirmation of this is cited in the patent literature. 

Carboxylic butadiene-acrylonitrile copolymers have been employed in blends with selected phenolic resins as metal-to-metal adhesives. ... 

Third Monomers. In order to achieve certain property improvements, nitrile mbber producers add a third monomer to the emulsion polymerization process. When methacrylic acid is added to the polymer stmcture, a carboxylated nitrile mbber with greatly enhanced abrasion properties is achieved (9). Carboxylated nitrile mbber carries the ASTM designation of XNBR. Cross-linking monomers, eg, divinylbenzene or ethylene glycol dimethacrylate, produce precross-linked mbbers with low nerve and die swell. To avoid extraction losses of antioxidant as a result of contact with fluids duriag service, grades of NBR are available that have utilized a special third monomer that contains an antioxidant moiety (10). FiaaHy, terpolymers prepared from 1,3-butadiene, acrylonitrile, and isoprene are also commercially available. 

Low molecular weight liquid nitrile rubbers with vinyl, carboxyl or mercaptan reactive end groups have been used with acrylic adhesives, epoxide resins and polyesters. Japanese workers have produced interesting butadiene-acrylonitrile alternating copolymers using Ziegler-Natta-type catalysts that are capable of some degree of ciystallisation. 

Other polymers used in the PSA industry include synthetic polyisoprenes and polybutadienes, styrene-butadiene rubbers, butadiene-acrylonitrile rubbers, polychloroprenes, and some polyisobutylenes. With the exception of pure polyisobutylenes, these polymer backbones retain some unsaturation, which makes them susceptible to oxidation and UV degradation. The rubbers require compounding with tackifiers and, if desired, plasticizers or oils to make them tacky. To improve performance and to make them more processible, diene-based polymers are typically compounded with additional stabilizers, chemical crosslinkers, and solvents for coating. Emulsion polymerized styrene butadiene rubbers (SBRs) are a common basis for PSA formulation [121]. The tackified SBR PSAs show improved cohesive strength as the Mooney viscosity and percent bound styrene in the rubber increases. The peel performance typically is best with 24—40% bound styrene in the rubber. To increase adhesion to polar surfaces, carboxylated SBRs have been used for PSA formulation. Blends of SBR and natural rubber are commonly used to improve long-term stability of the adhesives. 

CTBN type elastomers (carboxyl-terminated butadiene acrylonitrile) used to toughen this epoxy system. The Tg peak of the elastomer (-30°Q was shifted to higher temperatures suggesting that electron interaction resulted in crosslinking. The fact that the Tg peak disappeared at 10 rads suggests that crosslinking in the elastomer was extensive at high dose levels. 

Several polymers based on 1,3-dienes are used as elastomers. These include styrene-1,3-butadiene (SBR), styrene-1,3-butadiene terpolymer with an unsaturated carboxylic acid (carboxylated SBR), acrylonitrile-1,3-butadiene (NBR or nitrile rubber) (Secs. 6-8a, 6-8e), isobutylene-isoprene (butyl rubber) (Sec. 5-2i-l), and block copolymers of isoprene or... 

CTBN Carboxyl-Terminated Butadiene Acrylonitrile Rubber... 

Piperidine and carboxyl terminated butadiene acrylonitrile copolymer (CTBN) at 75 °C. 

CTBN carboxyl-terminated butadiene-acrylonitrile rubber DETA diethylenetriamine... 

Rubber was a carboxyl-terminated butadiene-acrylonitrile copolymer. Mean diameter of rubber particles =1.6 pm. Rubber concentration was 15 phr, giving volume fraction of 0.18 4 Containing vf (glass) = 0.1 rubber = 15 phr... 

A 3300 molecular weight carboxyl terminated 80-20 butadiene-acrylonitrile random copolymer designated CTBN (I) (Figure 3). 

It is obvious from these data that CTBN (the carboxyl terminated butadiene-acrylonitrile copolymer) is the most effective modifier, and therefore it was selected for further study. As the concentration of the elastomer was increased to levels up to 100 parts, the impact also increased. The data in Table II show that the room temperature impact of ERL-4221 increased from 40 inch-lbs to greater than 320 inch-lbs by adding 100 phr or 33 wt % of CTBN. At very low temperatures ( —160°F) the impact of the system modified with 60 parts, or 23 wt %, of CTBN was 120 inch-lbs. These impact improvements appear to be directly proportional to the concentration of the elastomer modifier. 

The carboxyl terminated butadiene-acrylonitrile rubber, which is soluble initially in the liquid phase, precipitates out as a second phase during the crosslinking reaction of the epoxy. The cured specimens are... 

Effect of Molecular Configuration of Elastomer. The extent of the impact and strength improvements of ERL-4221 depends on the chemical structure and composition of the elastomer modifier. The data shown in Table I indicate that the carboxyl terminated 80-20 butadiene-acrylonitrile copolymer (CTBN) is the most effective toughening and reinforcing agent. The mercaptan terminated copolymer (MTBN) is considerably less effective as far as tensile strength and heat distortion temperature are concerned. The mercaptan groups are considerably less reactive with epoxides than carboxyls (4), and this difference in the rate of reaction may influence the extent of the epoxy-elastomer copolymerization and therefore the precipitation of the rubber as distinct particles. 

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