Polyphosphazene Wire Coverings.
Final rept. 31 Mar 75-30 Mar 76,
HORIZONS INC CLEVELAND OHIO
Pagination or Media Count:
A 23 C6H5O2PN- 4-C2H5C6H4O2PNn copolymer was selected from several candidates for compounding studies to develop fire-retardant electrical wire insulation. All formulations prepared did not contain halogen either in the polymer or in the filler system employed. A filler system based on silane-treated hydrated alumina, magnesium hydroxide, and dicumyl peroxide proved to be very effective. Formulations based on this recipe gave 1 tensile strength and elongations greater than 1000 psi and 100, respectively 2 dielectric constants less than 4.5 at 100 kHz 3 dielectric strengths greater than 800 voltsmil 4 NBS smoke densities of 65 and 22 in the flaming and nonflaming modes, respectively and 5 Limiting Oxygen Index values in the range of 34-40. Samples were submitted for an evaluation of flame spread index and a value of 11 was obtained for the only sample tested to date. These values met or exceeded contract goals with the exception of the elongation, which was somewhat low, but within acceptable limits. Other formulations gave lower dielectric constant and higher elongation, but there was some sacrifice in smoke density values.
- Polymer Chemistry
- Elastomers and Rubber