Polyox

Polyox Water Soluble Eesins, Union Carbide Corp., Danbury, Conn., 1988. 

Fig. 9. Melt flow index as a function of temperature for varying molecular weights of poly(ethylene oxide). WSR = Polyox water-soluble resins.

Only Japan and the United States have significant commercial faciUties for the production of poly(ethylene oxide) resins. In Japan, Meisei Chemical Works Ltd. produces Alkox and Sumitomo Seika Kagaky Co., Ltd., PEO. In the United States, Union Carbide Corp. produces Polyox. Precise figures have not been released on capacities or aimual production. 

Of the three worldwide manufacturers of poly(ethylene oxide) resins. Union Carbide Corp. offers the broadest range of products. The primary quaUty control measure for these resins is the concentrated aqueous solution viscosity, which is related to molecular weight. Specifications for Polyox are summarized in Table 4. Additional product specifications frequendy include moisture content, particle size distribution, and residual catalyst by-product level. 

Table 4. Aqueous Solution Viscosity Specifications for Polyox Resins ...

Polyox resin-grade Approx, mol Nominal resin Brookfield Speed, Viscosity at 25°C, Pa-s ... 

Considerable interest has been shown ia poly(ethylene oxide) for diverse appHcations ia food, drug, and cosmetic products. Such uses fall within the scope of the Federal Food, Dmg, and Cosmetic Act. The U.S. FDA has recognized and approved the use of poly(ethylene oxide) for specific food and food packaging uses. USP/NF-grades of Polyox water-soluble resins (Union Carbide Corp.) are available for pharmaceutical appHcations. 

In 1958 the Union Carbide Corporation introduced high molecular weight, highly crystalline ethylene oxide polymers under the trade name Polyox. Although similar in appearance to polyethylene they are miscible with water in all proportions at room temperature. 

Shiflett, Particle Size Investigation of Polyox WSR 301 Polymer Powders Using a Turbidity Technique", NSRDC 28-621 (1973) 45) Anon, Standard Method of Test for Fineness of Hydraulic Cement by the No 325 (45 p m) Sieve", ASTM C430-75 (1975) 46) D.J. 

Polyox Water soluble resins Union Carbide... 

The corrosion behavior of zinc-coated steel electrodes electrochemically modified by polypyrrole [311] and zinc electrode in solution containing reducing polymer (Polyox WSR-301) [312] was investigated. 

Materials. The polyethylene oxides were the commercial grades of Polyox produced by the Union Carbide Corp. Distilled water was used in all solutions. 

Shear Degradation. Aqueous solutions of Polyox were agitated vigorously with a 10-blade stirrer turning at 1080 r.p.m. The solution viscosities were measured at various times during the stirring period. 

Typical Experiment. Polyox resin, Grade WSR-5M5, was transferred to a stainless steel hopper positioned over a vibrating feeder. The belt speed was set at 90 inches per minute, and the accelerator was adjusted (with the shutter closed) to deliver a current of 250 /xa. at 2 m.e.v. The shutter was opened, and the feeder was activated. The calculated dose was 0.75 megarad. After irradiation, the viscosity of each sample was measured. The average 5% aqueous solution viscosity for 27 samples of one particular blend was 78 7 cp., and the average for 16 samples of another was 80 =b 5 cp. 

The striking changes in solution viscosity produced by the cobalt-60 y-ray irradiation of dry Polyox are shown in Table I. 

Table I. Effect on Bulk Viscosity Irradiation of Dry Polyox...

The initial molecular weight is an important factor in Polyox irradiations. The viscosities of 5% aqueous solutions are plotted as a function of total dose in Figure 2. The Polyox powder was irradiated in air with 2-m.e.v. electrons at rates of 200 to 4000 megarads per hour. The samples in decreasing molecular weight were as follows WSR-701, WSR-301, WSR-5M5, and WSR-35. The range is from about 107 to 2 X 10. This... 

The effect of irradiation on the shear stability of Polyox solutions is shown in Figure 3. The viscosities before agitation were comparable, and it is apparent that after doses of approximately 0.4 megarad the solutions are much more stable than the unirradiated control. 

Radiation effects on polymers are more subtle than normal radiation chemistry, in that small chemical changes may have pronounced effects on the physical properties. Because of the sensitivity of these physical properties, the radiation chemistry of Polyox is best discussed in two parts—the chemical reactions occurring and the effects of these reactions on the physical properties. 

Figure 2. Effect of initial molecular weight on radiation degradation of Polyox...

Although the radiation chemistry of Polyox would not be expected to be exactly the same (because of the influence of crystal structure on radical migration, deactivation of excited species, etc.), it is still reasonable to use their ratios to estimate the initial radical production in our system. The corresponding values for total bond cleavage in Polyox are as follows (calculated for a molecule containing 8 C—H bonds, 4 C—O bonds, and 2 C—C bonds) ... 

Nitta et al. (12, 13) observed a persistent doublet in the ESR spectrum above 0°C. and ascribed it to this backbone polymer radical. Our corresponding measurements on Polyox at room temperature are qualitatively identical (20). These backbone radicals are the ones presumed to enter into the crosslinking reaction, especially in the absence of oxygen. 

Little RC (1969) Flow properties of polyox solutions Ind Eng Chem Fundam 8 557... 

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