Butadiene-acrylonitrile random copolymer

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

Figure 13.7 Variation of yield stress (

Figure 13.8 Fracture energy of epoxy networks cured with DDS (diamino dipheny sulfone) versus the initial DGEBA (diglycidyl ether of bisphenol A) ( ) neat systems ( ) with 10% CTBN (27% AN). Rubber = CTBN carboxy-terminated butadiene acrylonitrile random copolymer. (Pearson and Yee, 1989 with kind permission from Kluwer Academic Publisher.)... 

Rubbers and PESs are initially miscible with cyanate ester monomers. Phase separation occurs during the reaction. By plotting the phase diagrams (temperature vs. conversion), it is possible to compare the effects of chain ends and AN content in butadiene-acrylonitrile random copolymers and the effect of molar mass in PES. The cyanate ester monomer based on bisphenol A is a better solvent than DPEDC, and both dicyanates are better solvents than DGEBA. 

HTBN Hydroxyl terminated butadiene acrylonitrile random copolymer... 

Styrene-Butadiene Random Copolymer, 25% (wt) Styrene (SBR) Styrene-Butadiene Block Copolymer, about 25% Styrene (YSBR) Cis-1,4- Polyisoprene (Natural Rubber NR, Also Made Synthetically IR) Cis-1,4 Polybutadiene (BR) Polychloroprene (CR), Neoprene Butadiene-Acrylonitrile Random Copolymer, Variable % Acrylonitrile (NBR) Reclaimed Rubber (Whole Tires) (Mainly NR and SBR)... 

Fig. 13. Experimental CPC (A) and calculated binodal (broken curve) and spinodal (dotted curve) curves for a binary system composed of a DGEBA-based epoxy monomer (M = 479 gmol ) and a carboxyl-terminated butadiene-acrylonitrile rubber (CTBN) (Reprinted from Polymer, 30, D. Verchere, H. Sautereau, J.P. Pascault, S.M. Mos-chiar, C.C. Riccardi, R.J.J. Williams, Miscibility of epoxy monomers with carboxyl-terminated butadiene-acrylonitrile random copolymers, 107 -115, Copyright (1989), with kind permission from Butterworth-Heinemann journals, Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington 0X5 1GB, UK)...

The cyclotrimerization of a cyanate ester (4,4 dicyanato-1,1 diphenylethane, CE) (Fig. 16), in the presence of a butadiene-acrylonitrile random copolymer terminated by non-functional groups (NFBN), has been analyzed [89]. 

Epoxy prepolymers with rubber CORI Carboxyl-terminated butadiene-acrylonitrile random copolymer Taha et al. 1997... 

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... 

Such copolymers of oxygen have been prepared from styrene, a-methylstyrene, indene, ketenes, butadiene, isoprene, l,l-diphen5iethylene, methyl methacrjiate, methyl acrylate, acrylonitrile, and vinyl chloride (44,66,109). 1,3-Dienes, such as butadiene, yield randomly distributed 1,2- and 1,4-copolymers. Oxygen pressure and olefin stmcture are important factors in these reactions for example, other products, eg, carbonyl compounds, epoxides, etc, can form at low oxygen pressures. Polymers possessing dialkyl peroxide moieties in the polymer backbone have also been prepared by base-catalyzed condensations of di(hydroxy-/ f2 -alkyl) peroxides with dibasic acid chlorides or bis(chloroformates) (110). 

Poly(butadiene- (9-acrylonitrile) [9008-18-3] NBR (64), is another commercially significant random copolymer. This mbber is manufactured by free-radical emulsion polymerization. Important producers include Copolymer Rubber and Chemical (Nysyn), B. F. Goodrich (Hycar), Goodyear (Chemigum), and Uninoyal (Paracdl). The total U.S. production of nitrile mbber (NBR) in 1990 was 95.6 t (65). The most important property of NBR mbber is its oil resistance. It is used in oil well parts, fuels, oil, and solvents (64) (see Elastomers, synthetic— nitrile rubber). 

The economic importance of copolymers can be cleady illustrated by a comparison of U.S. production of various homopolymer and copolymer elastomers and resins (102). Figure 5 shows the relative contribution of elastomeric copolymers (SBR, ethylene—propylene, nitrile mbber) and elastomeric homopolymers (polybutadiene, polyisoprene) to the total production of synthetic elastomers. Clearly, SBR, a random copolymer, constitutes the bulk of the entire U.S. production. Copolymers of ethylene and propylene, and nitrile mbber (a random copolymer of butadiene and acrylonitrile) are manufactured in smaller quantities. Nevertheless, the latter copolymers approach the volume of elastomeric butadiene homopolymers. 

We commonly copolymerize styrene to produce random and block copolymers. The most common random copolymers are styrene-co-acrylonitrile and styrene-co-butadiene, which is a synthetic rubber. Block copolymerization yields tough or rubbery products. 

ABS resin (acrylonitrile-butadiene-styrene) is an example of a random copolymer with three different monomer units, not necessarily present in the same amount. 

Homopolymers of polybutadiene can consist of three basic isomeric forms (czs-1,4, trans-1,4, and 1,2 vinyl), and these can be present in different sequential order. Copolymers may obtain a variety of co-monomers, such as styrene, acrylonitrile, etc. Depending on their distribution in the chain, random copolymers or block copolymers of different types and perfection can be produced. There are many synthetic elastomers based on butadiene available commercially. 

A 1700 molecular weight mercaptan terminated random copolymer of 70% butadiene and 30% acrylonitrile designated MTBN (5) (Figure 4). 

Another widely used copolymer is high impact polystyrene (PS-HI), which is formed by grafting polystyrene to polybutadiene. Again, if styrene and butadiene are randomly copolymerized, the resulting material is an elastomer called styrene-butadiene-rubber (SBR). Another classic example of copolymerization is the terpolymer acrylonitrile-butadiene-styrene (ABS). Polymer blends belong to another family of polymeric materials which are made by mixing or blending two or more polymers to enhance the physical properties of each individual component. Common polymer blends include PP-PC, PVC-ABS, PE-PTFE and PC-ABS. 

Random copolymers -A-A-A-B-A-B-B-A-A- Styrene-butadiene rubber Styrene-acrylonitrile rubber Ethylene-vinyl acetate copolymer... 

Wettability of Elastomers and Copolymers. The wettability of elastomers (37, 38) in terms of critical surface tension was reported previously. The elastomers commonly used for the reinforcement of brittle polymers are polybutadiene, styrene-butadiene random and block copolymers, and butadiene-acrylonitrile rubber. Critical surface tensions for several typical elastomers are 31 dyne/cm. for "Diene rubber, 33 dyne/cm. for both GR-S1006 rubber and styrene-butadiene block copolymer (25 75) and 37 dyne/cm. for butadiene-acrylonitrile rubber, ( Paracril BJLT nitrile rubber). The copolymerization of butadiene with a relatively polar monomer—e.g., styrene or acrylonitrile—generally results in an increase in critical surface tension. The increase in polarity is also reflected in the increase in the solubility parameter (34,39, 40) and in the increase of glass temperature (40). We also noted a similar increase in critical surface tensions of styrene-acrylonitrile copolymers with the... 

ABS and Related Materials. The so-called ABS (acrylonitrile-buta-diene-styrene—monomers 1, 2, and 3) materials comprise a class of compounds that consists of either blends or grafts (41). All have three monomers divided between two different polymers in a 1,2 and 1,3 combination mode. Blends of styrene-butadiene (1,2) random copolymers with styrene-acrylonitrile (1,3) random copolymers result in toughened plastics the common-mer, styrene, improves compatibility. The material may be described ... 

Acrylonitrile-Butadiene Rubber. This rubber, normally known as NBR, is a random copolymer of acrylonitrile and butadiene in which the acrylonitrile content lies in the range 15-50% (w/w). A diagram of the chain is shown below ... 

Langer (13) has also disclosed the use of alkyllithium and dialkyl-magnesium tertiary diamine complexes as catalysts for copolymerization of ethylene and other monomers such as butadiene, styrene, and acrylonitrile to form block polymers. Examples are given in which polybuta-dienyllithium initiates a polyethylene block, as well as vice-versa. Random copolymers of these two were also prepared, and other investigators have used not only tertiary diamines but hexamethylphosphoramide (14) and tetramethylurea (15) as nitrogenous base cocatalysts in such polymerizations. Antkowiak and co-workers (11) showed the similarity of action of diglyme and TMEDA in copolymerizations of styrene and... 

Random Copolymers. Originally, only random copolymers (see Figure 1) could be made by charging two monomers simultaneously and using free-radical initiators. Typical examples from the 1930s are the first synthetic rubber materials, which were the random copolymers of butadiene with either styrene or acrylonitrile, and the first fully synthetic fiber, a random copolymer of vinyl chloride with vinyl acetate. 

The UV absorption in the 260 nm region is frequently used to evaluate styrene content in styrene-based polymers (2, 2, 3, 4, 5, 6, 7). Calibration curves for polystyrene solutions are usually based on the assumptions that the UV absorption of the copolymer depends only on the total concentration of phenyl rings, and the same linear relationship between optical density and styrene concentration that is valid for polystyrene holds also for its copolymers. These assumptions are quite often incorrect and have caused sizable errors in the analysis of several statistical copolymers. For example, anomalous patterns of UV spectra are given by random copolymers of styrene and acrylonitrile (8), styrene and butadiene (8), styrene and maleic anhydride (8), and styrene and methyl methacrylate (9, 10, 11). Indeed, the co-monomer unit can exert a marked influence on the position of the band maxima and/or the extinction... 

When a mixture of styrene and acrylonitrile is polymerized in the presence of a polybutadiene latex by an emulsion radical process, an acrylonitrile-butadiene-styrene (ABS) copolymer is obtained. This ABS copolymer is actually a mixture of (a) a graft copolymer which contains some of the styrene/acrylonitrile (ST/AN) copolymer chemically bound to the polybutadiene backbone, and (b) a random copolymer, conventionally designated as a linear copolymer, which is not bound to the polybutadiene backbone but which consists of the portion of the styrene/acrylonitrile monomer that has polymerized separately. 

Copolymers can also be a combination of types. For exampie, acryionitriie/ buta-diene/styrene (ABS) is a two-phase poiymer system that combines a random copolymer of styrene and acrylonitrile (SAN) and a dispersed graft copoiymer made of butadiene rubber grafted onto the SAN backbone (Fig. 3.10). 

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