Chloroprene rubber, poly

CR (Chloroprene rubber) Poly(2-chloro-1,3-butadiene) Unfilled, vulc. 1.2-1.25 1-3 13-22 800-1000... 

Chloroprene or Neoprene Rubber (CR). Chloroprene rubber (poly-2-chlorob-utadiene) is produced by the emulsion polymerization of 2-chlorobutadiene, in the presence of a free-radical initiator. Its general chemieal structure can be represented as... 

Park et al. [20] reported on the synthesis of poly-(chloroprene-co-isobutyl methacrylate) and its compati-bilizing effect in immiscible polychloroprene-poly(iso-butyl methacrylate) blends. A copolymer of chloroprene rubber (CR) and isobutyl methacrylate (iBMA) poly[CP-Co-(BMA)] and a graft copolymer of iBMA and poly-chloroprene [poly(CR-g-iBMA)] were prepared for comparison. Blends of CR and PiBMA are prepared by the solution casting technique using THF as the solvent. The morphology and glass-transition temperature behavior indicated that the blend is an immiscible one. It was found that both the copolymers can improve the miscibility, but the efficiency is higher in poly(CR-Co-iBMA) than in poly(CR-g-iBMA),... 

Emulsion polymerization is the most important process for production of elastic polymers based on butadiene. Copolymers of butadiene with styrene and acrylonitrile have attained particular significance. Polymerized 2-chlorobutadiene is known as chloroprene rubber. Emulsion polymerization provides the advantage of running a low viscosity during the entire time of polymerization. Hence the temperature can easily be controlled. The polymerizate is formed as a latex similar to natural rubber latex. In this way the production of mixed lattices is relieved. The temperature of polymerization is usually 50°C. Low-temperature polymerization is carried out by the help of redox systems at a temperature of 5°C. This kind of polymerization leads to a higher amount of desired trans-1,4 structures instead of cis-1,4 structures. Chloroprene rubber from poly-2-chlorbutadiene is equally formed by emulsion polymerization. Chloroprene polymerizes considerably more rapidly than butadiene and isoprene. Especially in low-temperature polymerization emulsifiers must show good solubility and... 

Butadiene is used primarily in the production of synthetic rubbers, including styrene-butadiene rubber (SBR), polybutadiene nibber (BR), styrene-butadiene latex (SBL), chloroprene rubber (CR) and nitrile rubber (NR). Important plastics containing butadiene as a monomeric component are shock-resistant polystyrene, a two-phase system consisting of polystyrene and polybutadiene ABS polymers consisting of acrylonitrile, butadiene and styrene and a copolymer of methyl methacrylate, butadiene and styrene (MBS), which is used as a modifier for poly(vinyl chloride). It is also used as an intermediate in the production of chloroprene, adiponitrile and other basic petrochemicals. The worldwide use pattern for butadiene in 1981 was as follows (%) SBR + SBL, 56 BR, 22 CR, 6 NR, 4 ABS, 4 hexamethylenediamine, 4 other, 4. The use pattern for butadiene in the United States in 1995 was (%) SBR, 31 BR, 24 SBL, 13 CR, 4 ABS, 5 NR, 2 adiponitrile, 12 and other, 9 (Anon., 1996b). 

ABA ABS ABS-PC ABS-PVC ACM ACS AES AMMA AN APET APP ASA BR BS CA CAB CAP CN CP CPE CPET CPP CPVC CR CTA DAM DAP DMT ECTFE EEA EMA EMAA EMAC EMPP EnBA EP EPM ESI EVA(C) EVOH FEP HDI HDPE HIPS HMDI IPI LDPE LLDPE MBS Acrylonitrile-butadiene-acrylate Acrylonitrile-butadiene-styrene copolymer Acrylonitrile-butadiene-styrene-polycarbonate alloy Acrylonitrile-butadiene-styrene-poly(vinyl chloride) alloy Acrylic acid ester rubber Acrylonitrile-chlorinated pe-styrene Acrylonitrile-ethylene-propylene-styrene Acrylonitrile-methyl methacrylate Acrylonitrile Amorphous polyethylene terephthalate Atactic polypropylene Acrylic-styrene-acrylonitrile Butadiene rubber Butadiene styrene rubber Cellulose acetate Cellulose acetate-butyrate Cellulose acetate-propionate Cellulose nitrate Cellulose propionate Chlorinated polyethylene Crystalline polyethylene terephthalate Cast polypropylene Chlorinated polyvinyl chloride Chloroprene rubber Cellulose triacetate Diallyl maleate Diallyl phthalate Terephthalic acid, dimethyl ester Ethylene-chlorotrifluoroethylene copolymer Ethylene-ethyl acrylate Ethylene-methyl acrylate Ethylene methacrylic acid Ethylene-methyl acrylate copolymer Elastomer modified polypropylene Ethylene normal butyl acrylate Epoxy resin, also ethylene-propylene Ethylene-propylene rubber Ethylene-styrene copolymers Polyethylene-vinyl acetate Polyethylene-vinyl alcohol copolymers Fluorinated ethylene-propylene copolymers Hexamethylene diisocyanate High-density polyethylene High-impact polystyrene Diisocyanato dicyclohexylmethane Isophorone diisocyanate Low-density polyethylene Linear low-density polyethylene Methacrylate-butadiene-styrene... 

These are the most important. The two double bonds mutually activate each other conjugation is essentially not destroyed by addition to the growing chain end. Therefore the conjugated dienes are difunctional monomers. They are polymerized by a relatively simple mechanism. Of all the polymers generated in living tissues, we have so far been able to imitate most closely natural rubber, poly-cw-l,4-isoprene. Butadiene, isoprene and chloroprene are the dienes most often employed in macro-molecular chemistry. 

ALTERNATIVE NAMES. ACRONYMS, TRADE NAMES Poly(l-chloro-l-butenylene), poly(2-chloro-1.3-butadiene), chloroprene rubber (CR), GR-M, Baypren, Butaclor , Neoprene, Perbunan C, Skyprene... 

Synonyms 1,3-Butadiene, 2-chloro-, polymers 2-Chloro-1,3-butadiene homopolymer Chlorobutadiene polymer 2-Chloro-1,3-butadiene polymer Chloroprene polymer Chloroprene resin Chloroprene rubber CR Neoprene Neoprene rubber Poly (2-chlorobutadiene) Poly (2-chloro-1,3-butadiene) Poly (chloroprene)... 

Alkane sulfonates are applied in a widespread manner in emulsion polymerization. They are used as processing aids, in particular in the emulsion polymerization of vinyl chloride, vinyl acetate, styrene and acrylonitrile. Because they possess no double bonds, alkane sulfonates do not act as radical chain stoppers. Well-known lattices derived from emulsion polymerization are poly(vinyl chloride), ethylene-vinylacetate copolymers, polyacrylates, and butadiene and chloroprene rubbers. Alkane sulfonates also offer good stabilizing effects in lattices against coagulation by fillers. 

Table 35-4. Glass Transition Temperatures and Solubility Parameters of Various Vulcanized Elastomers and Their Mixtures. 8, Solubility Parameter Br, Poly (butadiene) CR Poly(chloroprene) NBR, Poly(butadiene-co-acrylonitrile) NR, Natural Rubber ...

Particularly thin articles (e.g., rubber gloves) are produced by dipcoating. In this case, the mold negative is dipped into a latex (a dispersion) or a paste for as long and/or as often as is necessary to obtain the desired thickness. The latex viscosity should be less than 12 Pa s the flow limit as low as possible. Latices of natural rubber poly(chloroprene), and silicones, as well as PVC pastes, are processed in this way. 

Properties Ethylene propylene diene Nitrile rubber Poly- chloroprene Natural rubber Poly- isoprene Styrene butadiene rubber Butyl rubber Polybutadiene... 

Although many different polymers were investigated for use in PPCC, latexes are the most widely used binders. The latexes that are in general use are styrene-butadiene rubber (SBR) and chloroprene rubber (CR) which are elastomeric polyacrylic ester (PAE), ethlene-vinyl acetate (EVA) and poly(styrene-acrylic ester) (SAE) which are thermoplastic. Besides latexes, epoxy resins, which are thermosetting, are also used in PPCC [11, 17]. 

Construction Materials. Superabsorbent polsrmers are used to control liquid water in a variety of construction-related products. Joint-sealing composites are made by blending superabsorbents into chloroprene rubber (54) or into poly(ethylene-co-vinyl acetate) (55). These composites are used like mortar in the concrete block walls of the structure. Gaps left during construction are subsequently filled as the superabsorbent swells in any water, and subsequent leaks are prevented. A water-blocking construction backfill has also been developed from cement, water absorbing polymer, and an asphalt emulsion (56). 

The most studied systems have been polypyrrole/ PVC blends [372-5]. The electrochemical polymerization of pyrrole on a platinum electrode covered with a film of PVC produces a dark-brown, ductile and flexible composite polymer film with an electrical conductivity comparable to polypyrrole (5-50 S cm ), and mechanical properties very similar to PVC. Bargon et al. [373] have observed that the mechanical properties of these PPy/PVC blends can be further improved by the addition of poly(chloroprene) rubber as a plasticizer. 

Liquid Natural rubber Poly- chloroprene (Neoprene) Butyl rubber Butadiene- styrene rubber (7L5% styrene) Butadiene- acrylonitrile rubber (18% acrylo- nitrile) Silicone rubber (dimethyl siloxane)... 

The major degradation product of natural rubber is l-methyl-4-(l-methylethenyl)cyclo hexene. The presence of this compound as the major degradation product along with 2-methyl-1,3-butadiene (monomer) and groups of compounds containing 15 and 20 carbon atoms (three and four monomer units) in the pyrolysate of a rubber is sufficient to identify it as natural rubber. Similarly, the presence of l-chloro-4-(l-chloroethenyl)cyclohexene and 2-chloro-l, 3-butadiene, the cyclic dimer and monomer of poly(chloroprene) rubber, in the pyrolysate of a rubber identify it as poly(chloroprene) rubber. A correlation between the crosslink density and the product ratio of isoprene dimer species to isoprene formed from pyrolysis of natural rubber vulcanisates has been reported 697436 [a.232]. The major products of the isoprene dimer species were l,4-dimethyl-4-vinylcyclohexene and... 

Poly(chloroprene) rubbers Nitrile rubbers Reclaim rubbers Polyurethane rubbers Poly(vinyl acetate) and copolymers Poly(vinyl ether)... 

Poly chloroprene rubber sponge (bonded with poly chloroprene rubber adhesive)... 

ABS, acrylonitrile-butadiene-styrene CR, chloroprene rubber EPDM, ethylene propylene diene monomer EPR, ethylene propylene HDPE, high-density polyethylene LDPE, low-density polyethylene LLDPE, linear low-density polyethylene NBR, nitrile-butadiene rubber PET, poly(ethylene terephthalate) PBT, poly(butylene terephthalate) PVC, poly(vinyl chloride) SBR, styrene butadiene mbber. 

Resistance to weathering. Zinc oxide and magnesium oxide stabilize poly-chloroprene against dehydrochlorination. Further, zinc oxide helps vulcanize the rubber, and magnesium oxide reacts with /-butyl phenolic resin to produce a resinate which improves heat resistance of solvent-borne polychloroprene adhesives. 

The first important commercial synthetic rubber was poly(chloroprene) which was made available for sale as Neoprene by DuPont in 1931. It is still made and sold today because of its superior resistance to oils, sunlight, and oxygen (ozone). 

Anthony, Caston, and Guth obtained considerably better agreement between the experimental stress-strain curve for natural rubber similarly vulcanized and the theoretical equation over the range a = 1 to 4. KinelP found that the retractive force for vulcanized poly-chloroprene increased linearly with a — l/a up to a = 3.5. 

---