Patent Number: 039502716
Section: description

The invention will be further described in the following examples: EXAMPLE 1 An E-CTFE resin containing 98.05 weight % of approximately equimolar ethylene and chlorotrifluoroethylene, 1.0% trialkylisocyanurate, 0.3% of a phosphite of a stearically hindered phenol, 0.15% distearyl-thiodiproprionate and 0.5% calcium oxide was ball blended with 20 weight % gadolinium oxide of average particle size 10 .mu. and compression molded into plaques 2 .times. 2 in. .times. 1/4 inch. These plaques were divided into three groups and each group exposed to concentrated nitric acid containing 0.5N HF. In one case, the nitric acid was boiled, in another the mixture run hot and the third group was kept at room temperature. After five weeks all samples were weighed and examined and found to have suffered no weight change and no degradation. Similarly, exposure to high degrees of radiation for an extended period of time resulted in no degradation. These results indicate that this gadolinium filled composition would be superior for use as Raschig rings, containers, pipes or in other applications requiring exposure to acidic and/or radioactive environments. EXAMPLE 2 The procedure of Example 1 was repeated using a PCTFE resin and resulted in a composition possessing similar properties on exposure to acidic and radioactive environments. EXAMPLES 3 - 5 The procedure of Example 1 was repeated using equivalent amounts of gadolinium boride, gadolinium aluminate and gadolinium aluminum borate. Again superior results were obtained. EXAMPLES 6 - 19 In order to show that these chloro-fluoro substituted ethylene compositions can be highly filled with gadolinium compounds and still retain superior mechanical properties, the following experiments were performed: The filling procedure of Example 1 was repeated to fill both E-CTFE and PCTFE resins, using filler in amounts of 1 1/2, 10, 25, 50, 75 and 90 weight percent. Composite test plaques were molded under 300 psi pressure and at temperature of 260.degree.C. for 20 minutes. Molding pressures were increased to 10,000 psi for PCTFE samples containing 75 weight percent filler. The mechanical properties of these plaques were tested with both polymers using flexural strength as the criterion. The results of these tests are tabulated in Table I. Table I ______________________________________ Mechanical Properties of Polymers Filled with Gadolinium Oxide Vol. % Bulk Flexural Stress Flexural Wt.% Gd.sub.2 O.sub.3 Measured at 1% Strain Modulus In E-CTFE Density (psi) (psi) ______________________________________ 0 0 1.69 2010 2 .times. 10.sup.5 1.5 .4 1.705 2000 2.1 .times. 10.sup.5 10 2.47 1.832 2210 2.2 .times. 10.sup.5 25 7.05 2.12 2570 2.7 .times. 10.sup.5 50 18.5 2.74 4160 4.3 .times. 10.sup.5 75 40.7 3.92 6500 (max) 8.2 .times. 10.sup.5 In PCTFE 0 0 2.15 1540 1.8 .times. 10.sup.5 1.5 .5 2.17 2040 1.6 .times. 10.sup.5 10 3.1 2.31 2220 2.1 .times. 10.sup.5 25 8.8 2.60 2580 2.7 .times. 10.sup.5 50 22.5 3.29 4390 4.4 .times. 10.sup.5 75 46.5 3.74 7830 10.8 .times. 10.sup.5 ______________________________________