Polyvinyl chloride Physical properties

PVC is a thermoplastic polymer. Its properties are usually categorized based on rigid and flexible PVCs.

Property


Density [g/cm3]
Thermal conductivity [W/(m•K)]
Yield strength [psi]
Young's modulus [psi]
Flexural strength (yield) [psi]
Compression strength [psi]
Coefficient of thermal expansion (linear) [mm/(mm °C)]
Vicat B [°C]
Resistivity [Ω m]
Surface resistivity [Ω]

Rigid PVC                     Flexible PVC


1.3–1.45                                             1.1–1.35
0.14–0.28                                           0.14–0.17
4500–8700                                       1450–3600
490,000
10,500
9500
5×10−5

65–100                                         Not recommended
1016                                                       1012–1015
1013–1014                                             1011–1012


Mechanical properties

PVC has high hardness and mechanical properties. The mechanical properties enhance with the molecular weight increasing but decrease with the temperature increasing. The mechanical properties of rigid PVC (uPVC) are very good; the elastic modulus can reach 1500-3,000 MPa. The soft PVC (flexible PVC) elastic is 1.5-15 MPa. However, elongation at break is up to 200-450%. PVC friction is ordinary; the static friction factor is 0.4-0.5, and the dynamic friction factor is 0.23.

Thermal and fire properties

The heat stability of raw PVC is very poor, so the addition of a heat stabilizer during the process is necessary in order to ensure the product's properties. PVC starts to decompose when the temperature reaches 140 °C, with melting temperature starting around 160 °C. The linear expansion coefficient of rigid PVC is small and has good flame retardancy, the Limiting oxygen index (LOI) being up to 45 or more. The LOI is the minimum concentration of oxygen, expressed as a percentage, that will support combustion of a polymer and noting that air has 20% content of oxygen.

Electrical properties

PVC is a polymer with good insulation properties, but because of its higher polar nature the electrical insulating property is inferior to non polar polymers such as polyethylene and polypropylene.
Since the dielectric constant, dielectric loss tangent value, and volume resistivity are high, the corona resistance is not very good, and it is generally suitable for medium or low voltage and low frequency insulation materials.

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