Butadiene-acrylonitrile copolymers, liquid rubbers

To control compatibility and other properties of butadiene/acrylonitrile copolymers with PVC, there is an optimum acrylonitrile content of 37%. For practical handling, the nitrile rubber is treated on rolls at normal temperatures, and afterwards the mixture is rolled with PVC at elevated temperatures. The reverse process—plasticizing PVC first and mixing with nitrile rubber afterwards—is not so favorable because discoloring and decomposition may occur. This can be avoided by simultaneously applying the liquid plasticizers. Nitrile content in-... 

Nevertheless, it would seem reasonable that, in the absence of any liquid plasticizer medium at all, mobility of ionic impurities would be reduced to such a low level that volume resistivity would remain high. For example, it is well known that polyvinyl chloride can be blended with nitrile rubber, such as Goodrich Hycar 1032 butadiene/acrylonitrile copolymer, and such polyblends are quite soft and flexible without the use of any liquid plasticizer at all (Table VII). 

The polyester resin used in this study, MR 13006 (Aristech Corporation), was supplied as a 60-wt% solution in styrene monomer. The epoxy resin, a digly-cidyl ether of bisphenol A (Epon 828), was obtained from Shell Chemical Company. The reactive liquid rubber, an amino-terminated butadiene-acrylonitrile copolymer (ATBN 1300 x 16), was provided by the BFGoodrich Company. The resin was mixed with additional styrene monomer to maintain the ratio of reactive unsaturation in the polyester-to-styrene monomer at 1 to 3. We added 1.5 wt% of tert-butylperbenzoate initiator to the solution, which we then degassed under vacuum. The mixture was poured between vertical, Teflon-coated, aluminum plates and cured under atmospheric pressure at 100 °C. In the modified compositions, the rubber was first dissolved in the styrene monomer, and then all the other components were added and the solution cured as described. In all the compositions, the ratio of the amine functions with respect to the epoxy functions was kept at 1 to ensure complete cure of the epoxy. 

Cured vinyl ester resins are fragile after curing like standard UPRs and thus need flexibilization. The flexibilization of vinyl ester resins is made using the known reactive rubber vinyl-terminated liquid elastomeric butadiene-acrylonitrile copolymer (VTBN) [76]. The macrostructure of the VTBN flex-... 

High molar mass epoxy prepolymers containing rabber dispersions based on carboxyl-terminated butadiene-acrylonitrile copolymer were prepared from initially miscible solution of low molar mass epoxy prepolymers, bisphenol A and carboxyl-terminated NBR. During chain extension inside a twin screw extruder due to epoxy-phenoxy and epoxy-carboxy reactions, a phase separation process occurs. Epoxy-phenoxy and epoxy-carboxy reactions were catalysed by triphenylphosphine. The effect of reaction parameters (temperature, catalyst, reactant stoichiometry) on the reactive extrasion process were analysed. The structure of the prepolymers showed low branching reactions (2-5%). Low molar mass prepolymers had a Newtonian rheological behaviour. Cloud-point temperatures of different reactive liquid butadiene aciylonitrile random copolymer/epoxy resin blends were measured for different rubber concentrations. Rubber... 

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. 

Abbreviations coiX-V] = copolymers of X and Y colX-b-Yl = block copolymers of poly X and poly Y ST = styrene MA = methyl acrylate MMA = methyl methacrylate AN = acrylonitrile BD = butadiene LR (liquid rubbers) = a, cj-polybutadiene-diols and -dicarboxylic acids Cell-Ac = cellulose acetate Cell-N02 = cellulose nitrate. 

Liquid polymers are useful as tackifiers for rubbers, 72) and acrylic coatings. The most interesting are hydroxytelechelic polybutadienes, especially liquid butadiene-acrylonitrile (85/15) copolymers (trademark CN-15, ARCO). This product, known since 1971 as a tackifier, has the following characteristics viscosity 493 poises at 30 °C, tv[n = 4400, hydroxyl number/chain = 2.5. The incorporation of 5% of CN-15 in ethylene-propylene rubber (EPT Nordel 1070) increases its tack considerably 173) close to that of natural rubber or butyl rubbers (Table 4.1). 

In order to improve the internal stress performance even further or to provide toughness for potting and adhesive applications it is advantageous to introduce reactive additives to the basic epoxide compound formulation. One of the most popular additives that has found considerable use in this type of application is a rubber-like liquid copolymer known as carboxyl terminated butadiene/acrylonitrile (CTBN). The generalised molecular structure of this material is ... 

Nitrile rubber is a copolymer of butadiene and acrylonitrile. It has the special property of being resistant to hydrocarbon liquids. 

Transition metal catalyzed hydrogenation in ionic liquids has also been applied to the hydrogenation of polymers. First studies were presented by Dupont s group which investigated the hydrogenation of acrylonitrile-butadiene copolymers [102]. These early studies were later expanded by Rosso and coworkers studying the rhodium catalyzed hydrogenation of polybutadiene (PBD), nitrile-butadiene rubber (NBR) and styrene-butadiene rubber (SBR) in a [BMIM][BF4]/toluene and a... 

Reactive liquid polymers (RLPs) The Uquid rubbers most often used in epoxy adhesives are those based on acrylonitrile-butadiene copolymers or on long-chain polyethers. To act as effective tougheners, however, they cannot be directly added to the formulation but have to be prereacted with some of the epoxy resin, or sometimes with the amino hardeners in two component paste adhesives (adduct fonnatiou). To achieve this, only RLPs with reactive eud groups are used by the formulator. 

Acrylonitrile ia-kr9-l6- nl-tr9l, - trel (1893) (propenenitrile, vinyl cyanide) n. (1) A monomer with the structure CH2=CH-CN. It is most useful in copolymers. Its copolymer with butadiene is nitrile rubber, and several copolymers with styrene exist that are tougher than polystyrene. It is also used as a synthetic fiber and as a chemical intermediate. (2) A raw material for the manufacture of synthetic resins and rubbers. It is a liquid at room temperatures, with a bp of 77° C and ftp of 0°C. Kadolph SJ, Langford AL (2001) Textiles. Pearson Education, New York. Odian G (2004) Principles of polymerization. Joihn Wiley and Sons, New York. 

Several excellent review articles describe nitrile rubber in great detail. This chapter will also briefly discuss the solution-polymerized functionally terminated telechelic liquid copolymers of butadiene and acrylonitrile. The latter materials, though much smaller in commercial volume, are achieving increased importance in high performance adhesive systems. 

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