Vinylpyridine rubbers

CARBOXY-ORGANOSILICAS - CHEMICALLY ACTIVE FILLERS FOR POLYMERS. COMMUNICATION . SYNTHESIS AND ADSORPTION PROPERTIES OF CARBOXY-ORGANOSILICAS AND THE REINFORCEMENT OF VINYLPYRIDINE RUBBER. 

Fig. 166. Kinetics of chemical stress relaxation (la, 2a, 3a, 4a) and the accumulation of residual deformation (1-4) in rubbers prepared on the basis of methyl-vinylpyridine rubber MVP-15. 1 and la) Rubber A, vulcanizing group sulfur + altax 2 and 2a) rubber C, vulcanizing agent benzotrichloride 3 and 3a) rubber based on SKB 4 and 4a) rubber B, vulcanizing group sulfur + altax and bonzotrichloride 5) rubber D, vulcanizing agent tetramethylthiuram disulfide.

Interest in vinylpyridine rubbers was renewed in 1955 when low-cost 2-methyl-5-vinylpyridine became available from petroleum sources by the following route ... 

Methyl-5-vinylpyiidine-butadiene copolymers (usually about 20 80 molar) are now commercially available. These copolymers are compounded and vulcanized in much the same way as styrene-butadiene copolymers and the vulcanizates have broadly similar properties the vinylpyridine rubbers show improved low temperature flexibility, abrasion resistance and oil resistance. 

An interesting characteristic of vinylpyridine rubbers is that much improved oil resistance may be obtained by including active organic halides (e.g., p-xylene hexachloride, benzotrichloride and tetrachloroquinone) in the formulation. These reagents lead to cross-linking by quaternization of the pyridine nitrogen, possibly as follows ... 

At the present time, the principal use of vinylpyridine rubbers is in latex form for the treatment of textile fibres to improve rubber-to-textile adhesion in tyres. 

Typical of these materials are the poly(vinyl thioethers), the poly(vinyl isocyanates), the poly(vinyl ureas) and the poly(alkyl vinyl ketones). Methyl isopropenyl ketone and certain vinylpyridine derivatives have been copolymerised with butadiene to give special purpose rubbers. 

The most common adhesive system used for bonding continuous fibers and fabrics to rubber is resorcinol-formaldehyde latex (RFL) system. In general, RFL system is a water-based material. Different lattices including nitrile and SBR are used as the latex for the adhesive system. 2-Vinylpyridine-butadiene-styrene is the common latex used in the adhesive recipe. RFL system is widely being used in tires, diaphragms, power transmission belts, hoses, and conveyor belts because of its dynamic properties, adhesion, heat resistance, and the capacity to bond a wide range of fabrics and mbbers. 

Mortality associated with acrylonitrile exposure was evaluated as part of a study of 15 643 male workers in a rubber plant in the United States (Akron, Ohio) (Delzell Monson, 1982). Included in the analysis were 327 workers who were employed for at least two years in the plant between 1 January 1940 and 1 July 1971, and who had worked in two departments where acrylonitrile was used, i.e., 81 worked only in the nitrile rubber manufacturing operation where exposures to 1,3-butadiene (see this volume), styrene (lARC, 1994a) and vinylpyridine also occurred and 218 only in the department where the latex was coagulated and dried. [No information on levels of exposure to acrylonitrile was provided ] Mortality among these workers was assessed through 1 July 1978 and compared with age- and calendar-time-specific rates for white men in the United States. SMRs were 0.8 ( = 74 95% CI, 0.7-1.0) for all causes of death, 1.2 ( = 22 95% CI, 0.8-1.9) for all cancers combined, 1.5 ( = 9 95% CI, 0.7-2.9) for lung cancer, 4.0 ( = 2 95% CI, 0.5-14.5) for urinary bladder cancer and 2.3 ( = 4 95% CI, 0.6-5.8) for cancers of the lymphatic and haematopoietic system. SMRs for lung cancer by duration of employment were [1.0] (4 observed, 3.8 expected) [95% CI, 0.3-2.7] for < 5 years, and [3.3] (5 observed, 1.5 expected) [95% CI, 1.1-7.8] for 5-14 years. No case was observed with duration > 15 years. 

Vinylpyridine is used in the terpolymer latex component of tire cord dips to improve the bonding of textile to rubber. Rubber hres built with steel cord, however, do not require vinylpyridine latex-based adhesives for the steel belt, Therefore, the consumption of vinylpvridines may be affected in the future,... 

P(S VPD) P(S-b-BR) PSA PSBMA poly(styrene-co-4-vinylpyridine) styrene-butadiene rubber block copolymer poly(sodium acrylate) poly(sec-butyl methacrylate)... 

Three homopolymer (diblock copolymer) phase boundary systems have been studied extensively the system of polystyrene (PS) and poly(2-vinylpyridine) (PVP) reinforced with diblock copolymers ofPS-PVP [22,25,28,31-33], the system of poly(methyl methacrylate) (PMMA) and PS reinforced with diblock copolymers of PMMA-PS [17,24,34,35] and the system of PMMA and poly(phe-nylene oxide) (PPO) reinforced by diblock copolymers of PMMA-PS [ 14,36,37]. Phase boundaries between PS and a crosslinked epoxy (XEp) were reinforced with carboxy-terminated PS chains whose -COOH ends reacted with either excess amines or epoxy to form a grafted brush at the interface [38,39]. In a similar manner, interfaces between rubber-modified PS (HIPS) and XEp reinforced with grafted PS-COOH chains have been investigated [40]. 

Water can be removed from methanol by a membrane of polyvinyl alcohol cross-linked with polyacrylic acid, with a separation factor of 465.204 A polymeric hydrazone of 2,6-pyridinedialdehyde has been used to dehydrate azeotropes of water with n- and /-propyl alcohol, s- and tort butyl alcohol, and tetrahydrofuran.205 The Clostridium acetobutylicum which is used to produce 1-butanol, is inhibited by it. Pervaporation through a poly(dimethyl-siloxane) membrane filled with cyclodextrins, zeolites, or oleyl alcohol kept the concentration in the broth lower than 1% and removed the inhibition.206 Acetic acid can be dehydrated with separation factors of 807 for poly(4-methyl-l-pentene) grafted with 4-vinylpyridine,207 150 for polyvinyl alcohol cross-linked with glutaraldehyde,208 more than 1300 for a doped polyaniline film (4.1 g/m2h),209 125 for a nylon-polyacrylic acid membrane (5400 g/m2h), and 72 for a polysulfone.210 Pyridine can be dehydrated with a membrane of a copolymer of acrylonitrile and 4-styrenesulfonic acid to give more than 99% pyridine.211 A hydrophobic silicone rubber membrane removes acetone selectively from water. A hydrophilic cross-linked polyvinyl alcohol membrane removes water selectively from acetone. Both are more selective than distillation.212... 

Pyridine bases namely 2 4-picolines are important commodity chemicals which are used in pharmaceuticals, rubber eind agricultural industries. 2-picoline is consumed for several different pesticides, and is used in the production of 2-vinylpyridine, which is a component of styrene-butadiene-vinylpyridine terpolymer latexes. The major outlet for 4-picoline is for the manufacture of 4-vinylpyridine and INH an anti-tubercular drug. The stringent specifications laid down for these products in pharmaceutical and agricultural applications can not be met from natural sources namely from coal carbonisation byproducts. Synthetic pyridine is the only answer to this problem. 

It is claimed that styrene/butadiene diblock polymers bring about an improvement in the hardness, strength, and processability of polybutadiene elastomers (27), as well as an improvement in the ozone resistance of neoprene rubber (28). Styrene diblock polymers have also been made with isoprene, a-methyIstyrene, methyl methacrylate, vinylpyridine, and a-olefins. Block copolymers of ethylene, propylene, and other a-olefins with each other have been made as well. Heteroatom block copolymers based on styrene or other hydrocarbons and alkylene oxides, phenylene oxides, lactones, amides, imides, sulfides, or slloxanes have been prepared. 

The largest use of a-picoline (2) is for production of 2-vinylpyridine (11) which, with butadiene and styrene, is converted into a terpolymer latex. This latex provides a coating that stiffens fabrics (e. g. nylon, polyester, rayon) that are incorporated into biased-ply car tires. The 2-vinylpyridinc assists in binding the rubber to the fabric carcass. a-Picoline is also used as a precursor to nitrapyrin (12), which prevents nitrogen loss from soil, and the herbicide picloram (13). 

Copolymerization studies demonstrated that aminimide, 1,1-dimethyl-l-(2-hydroxypropyl)amine methacrylimide (DHA) copolymerizes readily with 4-vinylpyridine (4VP) and N-vinylpyr-rolidone (NVP). These copolymers could he thermolyzed in solution to give soluble poly(4-vinylpyridine-co-isopropenyl isocyanate) and poly(N-vinylpyrrolidone-co-isopropenyl isocyanate) materials. The reactivity ratios of each monomer pair were determined, and the Alfrey-Price Q and e values for DHA were calculated for DHA (Mt)-4VP (M2), r, = 0.41, r = 0.77, Q = 0.68, and e = 0.58 and for DHA (Mt)-NVP (Mg), r2 = 0.15, r2 = 0.35, Q = 0.14, and e = 0.58. The DHA-4VP copolymers quaternized readily to give a new family of water-soluble polyelectrolyte materials. The various copolymers were examined as adhesion promoters for rubber-tire cord composites. 

The literature offers numerous examples of investigations of copolymers of vinylpyridines and N-vinylpyrrolidones and of their use in adhesive applications. For example, 4-vinylpyridine (4VP) has been grafted onto rubber and used in copolymers blended with rubber to improve the adhesion of rubbers to metals and other tire cord materials (2, 3, 4). Poly(N-vinylpyrrolidone) has very good adhesion to glass, metals, and various plastics and can be used to give improved adhesion between glass fiber and other plastics in glass fiber-... 

In rubber technology, the use of mercapto-l,2,4-thiadiazoles for several purposes507-510 has been described. Both monomeric511 and polysulfide structures512 are suitable rubber cross-linking agents. Polyethylene sheet is stabilized and protected by the addition (0.5%) of 2,4-dimethyl-l,2,4-thia-diazolidine-3,5-dithione.513 Poly(thiadiazolyl tetrasulfide) similarly stabilizes poly(vinylpyridines).514... 

Radiation-induced Degradation.—There have been several reports on radiation effects in polymers,288 including single crystals,287 fluoropolymers,288 polyamides,289 polysiloxanes,270 polyethylene and its copolymers,271 polypropylene,272 polyolefins,273 polystyrene and its copolymers,274 poly(vinyl chloride) and related polymers,275 rubbers,278 polysulphones and other sulphur-containing polymers,277 polycarbonate,278 nylon,279 poly(vinylpyridines),280 and wool.281... 

Gel-immobilized catalytic systems (GCS) represent swelled polymer composites in which active sites of the particular metal complex are inunobilized. Graft copolymers of ethylene-propylene rubber (EPRu) and ligands of 4-vinylpyridine, acrylic acid, vinylpyrrolidone, organophosphorus compounds etc. act as a polymeric supports (polymeric phases) [140]. The structure of metal complex sites immobilized in a polymer gel is presented by the following scheme ... 

New types of metal-containing polymers can be effectively produced 1 construction of polymer supports in the form of gels which, in use, are capable of swelling, insoluble in the reaction medium, but permeable to the molecules, substrate and solvent (23-25). they are based on ethylene-prcpylene rubbers and also ternary copolymers of ethylene, propylene and nonconjugated diene, siloxane rubbers with the radically grafted vinylpyridine, acrylic acid (AAc), methylmethacrylate (MMA), etc. Fu2 her cross-linking of the rubber base allows the syntheses of three-dimensional networks to avoid the dispersion of these particles in the reaction media. MX is bound within these networks. Such polymers were termed mosaic their structure is shown in Fig. 2. It is evident... 

The methyl group of a-picoline reacts, by virtue of its C-H acidity, with formaldehyde to form 2-pyridyl ethanol, which gives 2-vinylpyridine in the presence of bases. Vinylpyridine serves as a co-monomer in the production of modified styrene-butadiene rubber and special polyacrylic fibers to improve dye absorption. 

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