PVDF (PolyVinyliDene Fluoride)

PVDF (PolyVinyliDene Fluoride)

PVDF Properties and Characteristics

PVDF is generally used in applications requiring the high purity, strength, and resistance to solvents, acids, bases and heat. Compared to other fluoropolymers, like PTFE, PFA, FEP, it has an easier melt process because of its relatively low melting point of around 177°C.

Material properties of fluoropolymers – A comparison

In general, the chemical resistance of these materials are superior to most other families of plastics. This “chemically inert” characteristic is closely allied to their superior performance in ultra pure environments. The chemical inertness varies between the fluoropolymers. The fully fluorinated resins such as PTFE, FEP, PFA and MFA exhibit chemical inertness to a wider range of chemicals than do the partially fluorinated polymers such as CTFE (or PCTFE) and ECTFE. A better property in one or two areas is accompanied by a diminished property in others (for example PTFE properties is better than PVDF in chemical resistance but it has lower mechanical properties at normal ambient temperatures. Fully fluorinated polymers (perfluoropolymers) such as PTFE, FEP and PFA offer better thermal (higher use temperature) and chemical resistance properties than their partially fluorinated counterparts like ECTFE or PCTFE. However, partially fluorinated resins posses better mechanical properties, such as tensile strength, toughness, abrasion and cut-through resistance at ambient temperatures.

The flex modulus of PVDF tubing is considerably higher than PTFE (relatively most flexible), FEP, PFA or MFA. This makes PVDF tubing considerably more rigid than the other materials; however it has higher tensile strength at ambient temperatures.

The selection of a resin for a specific use is based on criteria for that application; for example permeability at the use temperature may be a critical requirement and may override other features such as chemical resistance and tensile strength. In each case the choice of material is made by comparing the key property requirements and, of course, cost .

Maxiumn usage of temperatures for PVDF

Typical applications

Filtration and separation equipment (filters, membranes, housings), transport and storage systems, insulation on some kinds of electrical wires, circuit assembly and printed circuit ,board rework is PVDF-insulated, tactile sensor arrays, strain gauges and lightweight audio transducers, artificial membranes

Properties

Property Value Units Method
Tensile Strength, 73°F, at break 5075 - 7250
35 - 50
psi
MPa
D 638
Elongation at break, 73°F 20 - 50 % D 638
Flexural Strength, 73°F 2100
11165
psi
MPa
D 790
Impact Strength, Izod, 23 deg C, notched, 4mm thick 2.25
120
Ft-lbf/in
J/m
D 256
Yield StrengthAt 23 deg C 7685 - 8265
53 - 57
psi
MPa
D 638
Density 1.78 gm/cu.cm
Coefficient of friction, static 0.2 to 0.4 D 1894
Property Value Units Method
Coefficient of Linear Expansion 12 – 14 x 10-5 K-1 D 696
Melting Point 343
173
deg F
deg C
D 3418
Thermal Conductivity 1.39
0.2
Btu/hr-.ft-deg F
watt/meter-K
ASTM C 177
Specific Heat, at 300 deg K 0.287 – 0.382
1.2 – 1.6
Btu/lb/deg F
kJ/Kg/deg K
 

Heat Distortion Temperature,

66 lb/sq.in (0.455 MPa), 4 mm thick

293
145
deg F
deg C
D 648
Service Temperature to 302
to 150
deg F
deg C
 
Processing Temperature   deg F
deg C
 
Property Value Units Method
Surface Arc-Resistance   sec D 495
Volume Resistivity > 1014 ohm-cm D 257/DIN 53483
Surface Resistivity, @ 100% RH > 1014 Ohm sq-1 D 257/DIN 53483
1MHz, 23 deg C 7 ε D150-81
Property Value Units Method
Flame Rating+ V-0 Class UL-94
Refractive Index 1.41 – 1.42 nD 25 D 542
Limiting Oxygen Index 44 % Oxygen D 2863
Water Absorption, 230 deg C, 10 Kg < 0.04 gm/10 min D 1238
Specific Gravity 1.78   ISO 1183
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