Design Properties - Solubility, Irradiation | Arkema High Performance Polymers

DESIGN PROPERTIES FOR SPECIAL APPLICATIONS

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.

**TABLE 1: ACTIVE* SOLVENTS**

Solvent	Boiling Point °C	Flash Point °C
Tetrahydrofuran	65	-17
Methyl Ethyl Ketone	80	-6
Dimethyl Formamide	153	67
Dimethyl Acetamide	166	70

*Solvent will dissolve at least 5-10 weight percent Kynar® resin at ambient temperature.

Solvent	Boiling Point °C	Flash Point °C
Tetramethyl Urea	177	65
Dimethyl Sulfoxide	189	35
Trimethyl Phosphate	195	107
N-Methyl-2-Pyrrolidone	202	95

TABLE 2: LATENT SOLVENTS**

Solvent	Boiling Point °C	Flash Point °C
Acetone	56	-18
Methyl Isobutyl Ketone	118	23
Glycol Ethers***	118	40
Glycol Ether Esters***	120	30
N-Butyl Acetate	135	24
Cyclohexanone	157	54
Diacetone Alcohol	167	61
Diisobutyl Ketone	169	49

^{**As a rule, latent solvents do not dissolve or substantially swell Kynar® homopolymer resin at room temperature.}
^{***Based on ethylene glycol, diethylene glycol, and propylene glycol.}

Solvent	Boiling Point °C	Flash Point °C
Ethyl Acetoacetate	180	84
Butyrolactone	204	98
Isophorone	215	96
Triethyl Phosphate	215	116
Carbitol Acetate	217	110
Propylene Carbonate	242	132
Glyceryl Triacetate	258	146
Dimethyl Phthalate	280	149

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.

TABLE 3: TENSILE MODULUS VS. RADIATION DOSE EXPOSURE (PSI)

RESIN GRADE	0 MRADS	2 MRADS	4 MRADS	8 MRADS	20 MRADS
Kynar^® 460	170	180	170	200	190
Kynar^® 720	230	220	230	220	240
Kynar^® 740	200	230	200	220	220
Kynar^® 760	200	190	190	210	220
Kynar Flex^® 2850	130	130	120	130	130

TABLE 4: ULTIMATE TENSILE STRENGTH VS RADIATION DOSE EXPOSURE (PSI)

RESIN GRADE	0 MRADS	2 MRADS	4 MRADS	8 MRADS	20 MRADS
Kynar^® 460	6200	6300	6000	6900	7200
Kynar^® 720	7400	7400	7300	7300	8400
Kynar^® 740	6900	6900	6900	7200	7900
Kynar^® 760	6300	6500	6700	7400	7800
Kynar Flex^® 2850	4700	4700	4900	4900	5600