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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

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