Kynar^® Resin
Design Properties, Irradiation

SOLUBILITY

Kynar^® PVDF resins have limited solubility. Tables 1 and 2 list active and latent solvents. Generally, Kynar^® resins are not soluble in aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated solvents, alcohols, acids, halogens, and basic solutions. Kynar Flex^® PVDF copolymers tend to be slightly more soluble than the Kynar^® PVDF homopolymers due to lower crystallinity. Kynar Superflex^® PVDF and Kynar Ultraflex^® PVDF can be highly soluble in select solvents.

RADIATION CROSS-LINKING

The different grades of Kynar^® homopolymer and copolymer resins are readily cross-linked and do not degrade when irradiated with moderate doses of high energy electron or gamma radiation.

The efficiency of cross-linking is influenced by the grade selection and molecular weight. Examples of Kynar^® PVDF-fabricated products utilizing radiation technology are heat-shrinkable tubing and insulated wire capable of withstanding continuous temperatures as high as 180°C (356°F).

RESISTANCE TO NUCLEAR RADIATION

The resistance of Kynar^® fluoropolymers to nuclear radiation is excellent. The original tensile strength of the resin is essentially unchanged after exposure to 100 megarads (Mrads) of gamma radiation from a Cobalt-60 source at 50°C (122°F) and in high vacuum (10-6 torr). The impact strength and elongation are slightly reduced due to cross-linking. This resistance to effects of radiation, combined with chemical resistance, has resulted in the successful use of Kynar^® components in nuclear reclamation plants.

Tables 3 and 4 below show minimal changes in tensile properties of Kynar^® homopolymer and Kynar Flex^® copolymer resins exposed to electron beam radiation in doses up to 20 Mrads according to ASTM D882 testing.