Chlorinated polyethylene CM

Setua and White (1991 a,b) used CM (chlorinated polyethylene) as a compatibilizer to improve the homogeneity of binary and ternary blends of CR, NBR, and EPR. NBR-EPM and CR-EPDM blends homogenize more rapidly when small amounts of CM are added. The presence of the compatibilizer leads to reductions in both the time needed for mixing, observed by flow visualization, and the domain size of the dispersed phase, observed by SEM. Arjunan et al. (1997) have used an ethylene acrylic acid copolymer and an EPR-g-acrylate as a compatibilizer for blends of EPDM-CR. The addition of the compatibilizer leads to the reduction in the phase size of the dispersed EPDM phase as well as increase in the tensile tear strength of the blend. 

Ta b I e 5.62 Upper and lower temperature limits for elastomeric materials (R C backbone with unsaturated units, M C backbone with only saturated units, 0 both C and 0 in the backbone, U C, N and 0 in the backbone, T C and S in the backbone, Q siloxane backbone NR natural rubber, IR isoprene rubber, BR butadiene rubber, CR chloroprene rubber, SBR styrene butadiene rubber, NBR nitrile rubber, HR butyl rubber, EPDM ethylene propylene ter-rubber, EAM ethylene vinyl acetate rubber, FKM fiuoro rubber, ACM acrylate rubber, CSM chlorosulfonated polyethylene, CM chlorinated polyethylene, ECO epichlorohydrin rubber (epichlorohydrin, ethylene oxide), AU polyurethane rubber (did), EU polyurethane rubber (diisocyanate), VMQ silicone rubber) specialties [229]... 

There have been some attempts to develop chlorinated polyethylene elastomers. The rubbers possess such attractive properties as very good oil, heat, flame, ozone, and weathering resistance and are also available in a convenient powder form. In spite of being marketed at competitive prices, the chlorinated polyethylene rubbers (designated as CM rubbers by ASTM) took... 

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 11,1 Ultrasonic velocity versus acrylonitrile-butadiene mbber/ethylene-propylene-diene monomer (NBR-EPDM) blend composition (a) no compatibiUzer, (b) with chloro-sulfonated polyethylene (CSM), and (c) with chlorinated polyethylene (CM). (From Pandey, K.N., Setua, D.K., and Mathur, G.N., Polym. Eng. Set, 45, 1265, 2005.)... 

CPE is the standardized acronym for thermoplastic chlorinated polyethylene. CM is the standardized acronym for elastomeric chlorinated polyethylene. 

Chlorinated polyethylene Chlorinated polyethylene Chloropoly- ethylene CM Not applicable Not applicable CE U6- 135 50-90 20 350 261... 

At room temperature, PE is a semi-crystalline plastomer (a plastic which on stretching shows elongation like an elastomer), but on heating crystallites melt and the polymer passes through an elastomeric phase. Similarly, by hindering the crystallisation of PE (that is, by incorporating new chain elements), amorphous curable rubbery materials like ethylene propylene copolymer (EPM), ethylene propylene diene terpolymer (EPDM), ethylene-vinyl acetate copolymer (EVA), chlorinated polyethylene (CM), and chlorosulphonated polyethylene (CSM) can be prepared. 

It should be pointed out that in both these cases the degree of chlorination differs from PVC by around 10%. By any estimate, the heat of mixing in these cases should be quite unfavourable. For example, an estimate based on solubility parameters and using group contribution gives for PVC (6 = 19.28 J cm ) and chlorinated polyethylene (45wt.-%Cl) (5 = 18.77 J cm" ), hence for a 50/50 mixture AH is -1-0.065 J per cm of mixture. Together with unfavourable equation-of-state terms and a small combinatorial entropy contribution these mixtures would not be expected to be miscible. 

Fig. 31. Experimental cloud point curve (dotted line) and simulated spinodals, for blends of an ethylene-vinyl acetate copolymer with chlorinated polyethylene. The initial curve (A) using an X,j (—4.2 Jcm ) value calculated from heat of mixing data and an adjusted (—0.0108 J cm K" ) was too flat bottomed. By adjusting (and the appropriate Q,j) a closer fit could be obtained (B) Q,j = -0.00678 (C)...

Solid perfluorocarbon surfaces also have extremely low surface energies Thus, poly(tetrafluoroethylene) (PTFE, Teflon) has a y value of 18.5 dyn cm which is the reason for the anti-stick and low-friction properties used for frying pans and other applications. That this effect is directly related to the fluorine content becomes obvious on comparison of the surface energies of poly(difluoro-ethylene) (25 dyn cm ), poly(fluoroethylene) (28 dyn cm ), and polyethylene (31 dyn cm Y If only one fluorine atom in PTFE is replaced by more polarizable chlorine, the surface energy of the resulting poly(chlorotrifluoroethylene) jumps to 31 dyn cm , the same value as for polyethylene [8]. 

Figure 2. Experimental data on copolymer resist sensitivities in relation to constituent monomer mole fraction. The following references and abbreviations are used P(ST-CMS), chloromethylated polystyrene (8) P(ST-CS), chlorinated polystyrene ( ) P(ST-IS), iodi-nated polystyrene (100 P(ET-CE), chlorinated polyethylene ( 6)a P(ET-BE), brominated polyethylene C165a P(ST-GMA), poly (styrene glycidyl methacrylate)...

CM. See Polyethylene elastomer, chlorinated CM-66. See Aluminum hydroxide CM-80. See Carrageenan (Chondrus crispus) CMaltidex CH] CMaltidex H] CMaitidex L CMaltidex M. See Maltitol CMannidex. See D-Mannitol CMC CMC Daicel 1150] CMC Daicei 116a, CMC Daicel 1220] CMC Daicel 124a, CMC Daicel 1260] CMC Daicel 220a, CMC Daicel] CMC sodium salt. See Carboxymethylcellulose sodium... 

Chlorinated Polyethylene (CM). Commercial grades of CM are produced by random chlorination of high-density polyetbylene in aqueous suspension. Uniform chlorination of the polymer requires elevated temperatures for the reaction. The general chemical structure of CM can be represented as follows ... 

Uses of Chlorinated Polyethylene Vulcanizates. CM is used in applications where aging resistance in hot air, oils, or chemicals is required and where good ozone, weathering, and flame resistance are required. Many such applications are in the wire and cable industry. 

For a polymer system such as ethylene-vinyl acetate with 45% acetate mixed with chlorinated polyethylene with a 52% chlorine content, the value of X,2 would be -4.9 J cm and Q,2 has a value of -0.0108 J cm °C Since xu is negative and xs is positive then Xe is small and negative, which indicates that the mixture will be homogeneous. Experimentally it is observed that this mixture at 83.5 °C is homogeneous and becomes heterogeneous at 90 °C. ... 

This family of elastomers is produced by the random chlorination of HDPE (the proprietary Tyrin is from Dow Chemical). The properties of chlorinated polyethylene (CM) include excellent ozone and weather resistance, heat resistance to 149°C (300°F) and even 177°C (350°F) in many types of oil, dynamic flex resistance, and resistance to abrasion. 

For many years chlorinated polyethylenes have been used mainly as additives to PVC. However in the 1970s rubber grades were introduced (e.g. Hostaprene—Hoechst, Dow CM—Dow Chemical). The polymers are cross-linked by peroxides, such as dicumyl peroxide, and plasticized with plasticizers of the types commonly used with PVC, e.g. diisooctyl phthalate. The vulcanizates are claimed to provide heat resistance in air and oil at temperatures up to 150 C at a lower cost than possible with older established polymers. 

Chlorine is reacted with polyethylene to produce chlorinated polyethylene rubber (CM). 

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