Solution butadiene rubber

LBR solution butadiene rubber LIS laboratory integration system... 

Butadiene copolymers are mainly prepared to yield mbbers (see Styrene-butadiene rubber). Many commercially significant latex paints are based on styrene—butadiene copolymers (see Coatings Paint). In latex paint the weight ratio S B is usually 60 40 with high conversion. Most of the block copolymers prepared by anionic catalysts, eg, butyUithium, are also elastomers. However, some of these block copolymers are thermoplastic mbbers, which behave like cross-linked mbbers at room temperature but show regular thermoplastic flow at elevated temperatures (45,46). Diblock (styrene—butadiene (SB)) and triblock (styrene—butadiene—styrene (SBS)) copolymers are commercially available. Typically, they are blended with PS to achieve a desirable property, eg, improved clarity/flexibiHty (see Polymerblends) (46). These block copolymers represent a class of new and interesting polymeric materials (47,48). Of particular interest are their morphologies (49—52), solution properties (53,54), and mechanical behavior (55,56). 

Styrene—Butadiene Rubber (SBR). This is the most important synthetic mbber and represents more than half of all synthetic mbber production (Table 3) (see Styrene-butadiene rubber). It is a copolymer of 1,3-butadiene, CH2=CH—CH=CH2, and styrene, CgH5CH=CH2, and is a descendant of the original Buna S first produced in Germany during the 1930s. The polymerization is carried out in an emulsion system where a mixture of the two monomers is mixed with a soap solution containing the necessary catalysts (initiators). The final product is an emulsion of the copolymer, ie, a fluid latex (see Latex technology). 

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. 

One of the most important solution blend polymers is high-styrene resin, which is manufactured by several companies worldwide. This is a latex blend of high-styrene rubber and normal styrene butadiene rubber. The different high-styrene master batches are available in the world as ... 

In the past chemical cure linings have been employed on a wide scale. These linings, usually based on natural rubber or acrylonitrile-butadiene rubber consist of a standard lining compound with a chemical activator such as dibenzylamine incorporated in the formulation. Prior to the application of the lining to the substrate, the individual sheets of rubber are dipped or brush coated with carbon disulphide or a solution of a xanthogen disulphide in a solvent. The carbon disulphide or xanthogen disulphide permeates the rubber and combines with the dibenzylamine to form an ultra-fast dithiocar-bamate accelerator in situ, and thus the rubber rapidly vulcanises at ambient temperature. 

Pandey et al. have used ultrasonic velocity measurement to study compatibility of EPDM and acrylonitrile-butadiene rubber (NBR) blends at various blend ratios and in the presence of compa-tibilizers, namely chloro-sulfonated polyethylene (CSM) and chlorinated polyethylene (CM) [22]. They used an ultrasonic interferometer to measure sound velocity in solutions of the mbbers and then-blends. A plot of ultrasonic velocity versus composition of the blends is given in Eigure 11.1. Whereas the solution of the neat blends exhibits a wavy curve (with rise and fall), the curves for blends with compatibihzers (CSM and CM) are hnear. They resemble the curves for free energy change versus composition, where sinusoidal curves in the middle represent immiscibility and upper and lower curves stand for miscibihty. Similar curves are obtained for solutions containing 2 and 5 wt% of the blends. These results were confirmed by measurements with atomic force microscopy (AEM) and dynamic mechanical analysis as shown in Eigures 11.2 and 11.3. Substantial earher work on binary and ternary blends, particularly using EPDM and nitrile mbber, has been reported. 

FIGURE 22.2 Flocculation behavior of the smaU-strain modulus at 160°C of uncross-linked solution-based styrene-butadiene rubber (S-SBR) composites of various molar mass with 50 phr N234, as indicated (left) and strain dependence of the annealed samples after 60 min (right). (From Kliippel, M. and Heinrich, G., Kautschuk, Gummi, Kunststoffe, 58, 217, 2005. With permission.)... 

FIGURE 27.4 ATR-IR spectra of 2 wt% trichloroisocyanuric acid (TCI) solution in MEK-treated styrene-butadiene rubber (SBR). Application of the chlorinating agent by immersion or by brush. (From Romero-Sanchez, M.D., Pastor-Bias, M.M., and Martfn-Martfnez, J.M., J. Adhes. Sci. TechnoL, 15, 1601, 2001.)... 

FIGURE 27.9 T-peel strength values of styrene-butadiene rubber (SBS) treated with chloramine T aqueous solutions with different pH/waterbome polyurethane adhesive/roughened leather joints, as a function of the pH value of the chloramine T aqueous solutions. A adhesion failure to the rubber, M cohesive failure in tbe rubber. (From Navarro-Banon, M.V., Pastor-Bias, M.M., and Martm-Martinez, J.M., Proceedings of the 27th Adhesion Society, Wilmington, NC.)... 

Femandez-Garcfa J.C., Orgiles-Barcelo, and A.C., Martm-Martmez J.M., 1991, Halogenation of styrene-butadiene rubber to improve its adhesion to polyurethanes, J. Adhes. Sci Technol, 5, 1065-1080. Oldfield D. and Symes T.E.F., 1983, Surface modification of elastomers for bonding, J. Adhes., 16, 77-96. Pastor-Bias M.M., Ferrandiz-Gomez T.P., and Martm-Martmez J.M., 2000, Chlorination of vulcanized styrene-butadiene rubber using solutions of trichloroisocyanuric acid in different solvents, J. Adhes. Sci. Technol, 14, 561-581. 

FI GU RE 33.9 Comparison of tan for a variety of fillers in solution-based styrene-butadiene rubber/butadiene... 

FIGURE 35.13 Typical fingerprint of a masterbatch mixing process of a solution-based styrene-butadiene rubber (S-SBR)/Silica/TESPT tread compound on a GK 320E (Harburg Freudenberger) with PES5 rotors. 

While both solution and solid-state NMR has been routinely applied to polymers for many years, there have been a few recent applications of HRMAS to polymer systems, analyzing polymerization mechanisms and characterizing the resulting polymers in the swollen state. The vulcanization of butadiene rubber by cyclic disulfides was shown to follow two different mechanisms with two different classes of sulfur compounds - cross-linking progressed... 

JSR Corp. Styrene-butadiene rubber, solution Styrene and butadiene Efficient and advanced technology yields S-SBR with excellent properties 1 1991... 

The free-radical kinetics described in Chapter 6 hold for homogeneous systems. They will prevail in well-stirred bulk or solution polymerizations or in suspension polymerizations if the polymer is soluble in its monomer. Polystyrene suspension polymerization is an important commercial example of this reaction type. Suspension polymerizations of vinyl ehloride and of acrylonitrile are described by somewhat different kinetic schemes because the polymers precipitate in these cases. Emulsion polymerizations aie controlled by still different reaetion parameters because the growing macroradicals are isolated in small volume elements and because the free radieals which initiate the polymerization process are generated in the aqueous phase. The emulsion process is now used to make large tonnages of styrene-butadiene rubber (SBR), latex paints and adhesives, PVC paste polymers, and other produets. 

Once the reaction has been completed the reactor product typically consists of polymer with other inert or unreacted reagents. The extraction of polymer in a form that can be further utilized needs special attention. The postprocessing may be relatively simple as in the addition of residual monomer scavenging systems to solution or emulsion polymer products to get close to 100% conversion and remove residuals that could be harmful to eventual users or the environment. It may also involve complex processes like controlled coagulation of styrene-butadiene emulsions to get styrene-butadiene rubber (SBR). 

Styrene-butadiene rubber could be produced by using emulsion and solution process, thus it can be divided into emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR). In this entry, we will describe their development and introduce their synthesis process, relationship between structure and property, processing property, blends, and applications. 

---