Chlorosulfonated polyethylene structure

Rubber blends with cure rate mismatch is a burning issue for elastomer sandwich products. For example, in a conveyor belt composite structure there is always a combination of two to three special purpose rubbers and, depending on the rubber composition, the curatives are different. Hence, those composite rubber formulations need special processing and formulation to avoid a gross dissimilarity in their cure rate. Recent research in this area indicated that the modification of one or more rubbers with the same cure sites would be a possible solution. Thus, chlorosulfonated polyethylene (CSP) rubber was modified in laboratory scale with 10 wt% of 93% active meta-phenylene bismaleimide (BMI) and 0.5 wt% of dimethyl-di-(/ r/-butyl-peroxy) hexane (catalyst). Mixing was carried out in an oil heated Banbury-type mixer at 150-160°C. The addition of a catalyst was very critical. After 2 min high-shear dispersive melt mix-... 

A technology developed at Du Pont75 combines the use of reactive sites on the oligomers with the initiation reaction. The resulting family of acrylic structural adhesives has become popularly known as second generation acrylics. They consist essentially of solutions of chlorosulfonated polyethylene (Du Pont Hypalon ) in acrylic or methacrylic monomers. The chlorosulfonyl groups present on the polymer will react with... 

Acrylic structural adhesives have been modified by elastomers in order to obtain a phase-separated, toughened system. A significant contribution in this technology has been made in which acrylic adhesives were modified by the addition of chlorosulfonated polyethylene to obtain a phase-separated structural adhesive (11). Such adhesives also contain methyl methacrylate, glacial methacrylic acid, and cross-linkers such as ethylene glycol dimethacrylate [97-90-5]. The polymerization initiation system, which includes cumene hydroperoxide, IV,AT - dimethyl-p- toluidine, and saccharin, can be applied to the adherend surface as a primer, or it can be formulated as the second part of a two-part adhesive. Modification of cyanoacrylates using elastomers has also been attempted copolymers of acrylonitrile, butadiene, and styrene ethylene copolymers with methylacrylate or copolymers of methacrylates with butadiene and styrene have been used. However, because of the extreme reactivity of the monomer, modification of cyanoacrylate adhesives is very difficult and material purity is essential in order to be able to modify the cyanoacrylate without causing premature reaction. 

STRUCTURE 5.1 Chlorosulfonated polyethylene. (Reprinted from O. Figovsky, V. Karchevky, and D. Beilin, Protective Crack-Resistant Waterborne Coatings Based on Vulcanized Chlorine-Sulpho-Polyethylene Scientific Israel Technological Advantages 3, nos. 1-2 (2001). With permission.)... 

Chlorosulfonated Polyethylene (CSM). CSM is produced by ultraviolet radiation of low-density polyethylene in an inert chlorinated solvent at 70 to 75°C in the presence of chlorine and sulfur dioxide. Its chemical structure can be represented as follows ... 

Figure C.3 General chemical structure of chlorosulfonated polyethylene (x is approximately 12 and y...

Chlorosulfonated polyethylene (CSM) [68037-39-8] describes a group of curable, halogenated olefin polymers, first introduced to the rubber industry by E. I. du Pont de Nemours and Co. in 1951 (1-5) under the trade name of Hypalon. They contain pendant chlorine and sulfonyl chloride groups and vary in consistency from soft and elastomeric to hard and plastic. The chemical structure may be represented by... 

Figures 8-26 and 8-27 show several types of air-supported structures. Figure 8-26 shows a simple arch section with spherical sections ends. The perimeter of structures, frequently made of such materials as chlorosulfonated polyethylene (Hypalon elastomer) coated on nylon...

Ethylene acrylic mbber is manufactured by M/s Dupont USA under the trade name of Vamac, and is about half ethylene and half methylacrylate. A small amount of cure site monomer in the molecule provides the ability to cross-link chemically. This rubber is the combination of two major chemicals which give its unique balance of properties. For instance, the backbone structure of the polymer molecule is saturated, and so it is inherently resistant to ozone attack. The acrylic segment provides oil resistance, and the ethylene segment yields low temperature performance. The added feature of this mbber is that there is no halogen present to become corroded. There is slightly more tendency to swell than a homopolymer, such as polyacrylate or acrylonitrile mbber, but it is approximately equal to silicone, chloroprene and Hypolan (chlorosulfonated polyethylene) mbbers. 

The technique was first applied to polyethylene and i-polypropylene revealing itself to be sensitive to crystallinity, lamellar orientation, crystal structure, and crystal defects (55). Thus it penetrates between lamellae attacks lamellar side surfaces more than their fold surfaces, a- more than /3-i-polypropylene and removes dislocation cores preferentially. As with chlorosulfonation, it allows systematic study of samples by cutting them open where desired. But it can also reveal the particular character of external or fracture surfaces, neither of which is usually random. 

Peterlin et al. [157] described the use of iodine vapor, at 60°C (24 h) to reveal the structure in PE fibrils drawn from solution grown single crystals. Andrews et al. [78] extended this method to prestaining a block of material prior to ultrathin sectioning. They showed the contrast enhancement of PE spherulites by action of the iodine. However, the iodine dissipates upon standing in air and is known to vaporize in the vacuum of the electron microscope. The chlorosulfonic acid method (Section 4.4.4) has replaced iodine staining of polyethylene. 

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