Polyacrylic butadiene rubber

Standard-grade PSAs are usually made from styrene-butadiene rubber (SBR), natural rubber, or blends thereof in solution. In addition to rubbers, polyacrylates, polymethylacrylates, polyfvinyl ethers), polychloroprene, and polyisobutenes are often components of the system ([198], pp. 25-39). These are often modified with phenolic resins, or resins based on rosin esters, coumarones, or hydrocarbons. Phenolic resins improve temperature resistance, solvent resistance, and cohesive strength of PSA ([196], pp. 276-278). Antioxidants and tackifiers are also essential components. Sometimes the tackifier will be a lower molecular weight component of the high polymer system. The phenolic resins may be standard resoles, alkyl phenolics, or terpene-phenolic systems ([198], pp. 25-39 and 80-81). Pressure-sensitive dispersions are normally comprised of special acrylic ester copolymers with resin modifiers. The high polymer base used determines adhesive and cohesive properties of the PSA. 

Latexes are usually copolymer systems of two or more monomers, and their total solids content, including polymers, emulsifiers, stabilizers etc. is 40-50% by mass. Most commercially available polymer latexes are based on elastomeric and thermoplastic polymers which form continuous polymer films when dried [88]. The major types of latexes include styrene-butadiene rubber (SBR), ethylene vinyl acetate (EVA), polyacrylic ester (PAE) and epoxy resin (EP) which are available both as emulsions and redispersible powders. They are widely used for bridge deck overlays and patching, as adhesives, and integral waterproofers. A brief description of the main types in current use is as follows [87]. 

A list of typical commercial pervaporation membranes [23] is given in Table 3.1. Commercial hydrophilic membranes are very often made of polyvinyl alcohol (PVA), with differences in the degree of crosslinking. Commercial hydrophobic membranes often have a top layer in polydimethyl siloxane (PDMS). However, a wide variety of membrane materials for pervaporation can be found in the literature, including polymethylglutamate, polyacrylonitrile, polytetrafluoroethylene, polyvinylpyrrolidone, styrene-butadiene rubber, polyacrylic acid, and many others [24]. A comprehensive overview of membrane materials for pervaporation is given by Semenova et al. [25],... 

FIGURE 9.17 Dependence of productivity and separation factor /3p C6H5CH3/H2O of membranes based on various rubbery polymers on the glass transition temperature of the polymer (pervaporation separation of saturated toluene/water mixture, T = 308 K) (1) polydimethyl siloxane (2) polybutadiene (3) polyoctylmethyl siloxane (4) nitrile butadiene rubber with 18% mol of nitrile groups (5) the same, 28% mol of nitrile groups (6) the same, 38% mol of nitrile groups (7) ethylene/propylene copolymer (8) polyepichlorohydrin (9) polychloroprene (10) pol3furethane (11) polyacrylate rubber (12) fluorocarbon elastomer. (From analysis of data presented in Semenova, S.I., J. Membr. Sci., 231, 189, 2004. With permission.)... 

Technology for preparing nanocomposites directly via compounding has been investigated by Vaia, Ishii, and Giannelis. Industrial R D efforts have focused on process technology (e.g., melt or monomer exfoliation processes), as there are a number of polymers (e.g., polyolefins) that do not lend themselves to a monomer process. Nanocomposites with a variety of polymers, including polyacrylates or methacrylates, polystyrene, styrene-butadiene rubber, epoxy, polyester, and polyurethane, are amenable to the monomer process. The enhancement of mechanical properties, gas permeability resistance, and heat endurance are the primary objectives for the application of PCN, and their success will establish PCNs as a major commercial product. 

The uses of mercaptans in polymers fall into three major categories chain transfer agents, additives such as stabilizers against heat or UV light, and monomers that incorporate an alkylmercapto group into their structure. Mercaptans r-dodecyl, n-dododecyl, etc. are excellent chain transfer agents used to control molecular weight of several different kinds of polymers, styrene butadiene rubber, acrylonitrile-butadiene-styrene, polyacrylates, to name a few. " " ... 

In the 1960s, styrene-butadiene rubber-, polyacrylic ester-,l and poly(vinylidene chloride-vinyl chloride)- modified mortars and concretes became increasingly used in practical applications. Since the 1960s, the practical research and development of polymer-modified mortar and concrete have been considerably advanced in various countries, particularly U.S.A., U.S.S.R., West Germany, Japan, and U.K. Consequently, a considerable number of publications including patents, books, papers, and reports have appeared. Of these, the main and important studies are as follows ... 

In particular, the commercial latexes widely used in the world are styrene-butadiene rubber (SBR), polychloroprene rubber (CR), polyacrylic ester (PAE) and poly(ethylene-vinyl acetate) (EVA) copolymers. Most commercial polymer latexes for cement modifiers contain proper antifoaming agents, and can be generally used without the addition of the antifoaming agents during mbcing. 

Besides melt intercalation, described above, in situ intercalative polymerization of E-caprolactone (e-CL) has also been used [231] to prepare polycaprolactone (PCL)-based nanocomposites. The in situ intercalative polymerization, or monomer exfoliation, method was pioneered by Toyota Motor Company to create nylon-6/clay nanocomposites. The method involves in-reactor processing of e-CL and MMT, which has been ion-exchanged with the hydrochloride salt of aminolauric acid (12-aminodecanoic acid). Nanocomposite materials from polymers such as polystyrene, polyacrylates or methacrylates, styrene-butadiene rubber, polyester, polyurethane, and epoxy are amenable to the monomer approach. 

These tests, however, do not identify certain chemically very inert plastics such as polyethylene, polypropylene, polyisobutylene, polystyrene, polymethyl methacrylate, polyacrylates, polyethylene terephthalate, natural rubber, butadiene rubber, polyisoprene, and silicones. Their identification requires specific individual reactions, described in Chapter 6. 

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. 

Examples of vulcanizable elastomers include natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene monomer-rubber (EPDM), butyl rubber (HR), polychloroprene or neoprene (CR), epichlorohydrin rubber (ECO), polyacrylate rubber (ACM), millable polyurethane rubber, silicone rubber, and flu-oroelastomers. Examples of thermoplastic elastomers include thermoplastic polyurethane elastomers, styrenic thermoplastic elastomers, polyolefin-based thermoplastic elastomers, thermoplastic polyether-ester (copolyester) elastomers, and thermoplastic elastomers based on polyamides. 

Looking at the historical development of the emulsion pol)nnerization, it is seen that the trigger factor in this development was the necessity for synthetic rubber in the wartime. The production of styrene/butadiene rubber (SBR) satisfied this requirement. Today, millions of tons of S)mthetic latexes are produced by the emulsion pol3merization process for use in wide variety of applications. In the S)mthetic latexes, the most important groups are styrene/butadiene copolymers, vinyl acetate homopol)rmers and copol)nners, and polyacrylates. Other synthetic latexes contain copolymers of ethylene, styrene, vinyl esters, vinyl chloride, vinylidene chloride, acrylonitrile, cloroprene and polyurethane. 

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]. 

Rudewicz and Munson [45] used this technique for the direct determination of additives in PP. The technique has also been used to determine oligomers in polyacrylates, PEG, siloxanes and polycarbonates [87], polyglycols [88] and adhesion promoters, primers and additives in the surface of PET film [89], volatile antioxidants in styrene-butadiene rubbers [34, 50], mercaptobenzothiazole sulfenamide accelerator in rubber vulcanisates [90] and divinyl benzene in styrene-divinyl benzene copolymer [91]. 

PMG polymethyiglutamate PDMS polydimethylsiloxane PVA polyvinylalcohol CA cellulose acetate PAN polyacrylonitrile PTFE Polytetrafluoroethylene PVP poly vinylpyrrolidbne SBR styrene-butadiene rubber NBR nitrile-butadiene rubber CTP cellulose tripropionate PAA polyacrylic acid ... 

BHT, butylated hydroxytoluene DBS, sodium dodecylbenzene sulfonate DSTDP, distearylthiodipropionate PAAE, polyamide amine epichlorohydrin PAM, polyacryl(methacrylate) PEG, polyoxyethylene lauryl ether SBR, styrene-butadiene rubber. 

Another area in which adhesives are very widely used in the textile industry is the manufacture of chemically bonded nonwovens. The nonwovens are preformed by the dry-layer or wet-layer process and subsequently bonded by spraying or impregnation with adhesives. The binders used generally are products based on polyacrylates, synthetic rubber, and vinyl polymers. Nitrile and styrene - butadiene rubbers are used for industrial nonwovens because of the need for resistance to oils, fats, and organic solvents. 

The first generation was introduced before 1950 and includes polystyrene, polyvinylchloride, low-density polyethylene, polyacrylates, polymethacrylates, glass-fibre reinforced polyesters, aliphatic polyamides, styrene-butadiene rubber and the first synthetic paints (alkyds). 

While natural rubber began as the basis for automobile tires, synthetic rubber products replaced natural rubber - partly as a consequence of the rubber shortage of World War II. Synthetic rubber products include styrene-butadiene rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), nitrile rubber, neoprenes, polysulfides, polyacrylate rubber, and a host of other products with 65% of all SBR... 

The most widely used elastomers are natural rubber [17], synthetic polyisoprene and butadiene rubbers, styrene-butadiene copolymers, ethylene-propylene rubber (specifically EPDM), butyl and halobutyl elastomers, polyurethanes, polysiloxanes, polychloroprenes, nitrile rubber, polyacrylic rubbers, fluorocarbon elastomers, and thermoplastic elastomers [18-20]. The examples which have unsaturation present in the repeat units (such as, the diene elastomers) have the advantage of easy cross-linkability, but the disadvantage of increased vulnerability to attack by reactants, such as oxygen and ozone. 

As the substrate sheet, a thin plastic film or tightly packed nonwoven cloth, such as polyester spanbond nonwoven cloth of approximately 0.15 mm, is used. A synthetic rubber, such as styrene-butadiene rubber or thermoplastic polyurethane elastomer, is used as a binder. In addition, a surfactant for hydrophilicity, an antioxidant for prevention of thermodeformation, and a silica-type inorganic filler for prevention of tackiness are used. For the superabsorbent polymer particles, various synthetic polymers, for example, polyacrylate and polyvinyl-type superabsorbent polymers, can be used. For this apphcation, the particle sizes are an important parameter, because they polymer is required to be within the coating layer, and as the absorption rate is no retarded, quickly protrude from the layer when swelling. 

Some of the discussed additives may affect electrical properties of the materials. There is not much information published on this subject. It is known from literature that fluoropolymer additives made a dramatic improvement in the processing rates of several polymers (ethylene oxide epichlorohydrin copolymer, silicone, polyacrylate, nitrile butadiene rubber, and ethylene propylene diene terpolymer) without affecting the dielectric constant and dissipation factors. It can be assumed that a similar effect can be obtained with some silicone additives, but in the remaining cases, these properties have to be analyzed if they are of importance. 

These admixtures are used to increase the bond strength in repair applications, to decrease shrinkage, increase tensile strength, etc. The polymers used include latexes, redispersible polymer powders, water-soluble polymers, liquid resins, and monomers. In practieal applications, styrene butadiene rubber, polyacrylic ester and polyvinylidene chloride-vinyl chloride, methylcellulose, etc., have been used. 

In an initial study, various antioxidants were evaluated in hydrogenated nitrile-butadiene rubber (HNBR), polyacrylic elastomer (ACM), and ethylene-acrylic elastomer (EAM), polymers which are frequently used in applications requiring high heat and oil resistance. Compounds of these elastomers were first immersed in ASTM 901 Oil to remove any soluble antioxidants that could be extracted in service, and later heat aged up to 21 days at 177°C in air. Similar agings were performed with samples placed in... 

Copolymer of styrene and acrylonitrile Copolymer of styrene and butadiene Natural rubber Chlorinated polyethylene Chlorosulfonated polyethylene Polyamides Polyesters Polyurethanes Polysulfones Polyacrylates Polyacrylamides Polydimethylsiloxane Copolymer of vinylidene fluoride and hexafluoropropylene... 

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