PVC strength

PVC is extensively used for municipal water supply/sewage pipes, spouts, profiles, etc., since its mechanical properties such as tensile strength and tensile modulus are better than those of polyolefin plastics, making products robust and durable. When plasticisers are added, PVC shows rubber-like elasticity with high tensile strength and fatigue strength, and can be used for industrial hoses, gaskets, automobile parts, and electric cable covering.

Tensile strength

The figure to the right shows the comparison of tensile strength of PVC products with other plastics. The tensile strength is expressed in terms of the maximum stress per unit area of the cross section when the test piece breaks by applied loads to both ends of the test piece. (An index shows the magnitude of force at break, when both ends of the test piece are pulled apart).

Tensile modulus

The figure to the left shows the comparison of tensile modulus of PVC products with other plastics. The tensile modulus is an index showing the magnitude of elongation, when a test piece is pulled apart. It is the equivalent of the spring constant.

Bending strength

The figure to the right shows the bending strength of PVC products in comparison with other plastics. It is expressed in terms of the maximum stress upon the breaking of the test piece, where the test piece is supported at two points apart and a vertical stress load is applied at the centre. (An index showing the magnitude of force at break, when the test piece is bent).

Compressive strength

The figure to the left shows the compressive strength of PVC products in comparison with other plastics. It is expressed in terms of the maximum stress at break per unit area of the cross section, when a vertical stress is applied to the test piece sandwiched by two pieces of the test panel.

Fatigue strength

The figure to the right shows the fatigue strength of PVC products in comparison with other plastics. It is expressed in terms of the maximum stress at which the test piece would not break after applying repeated stress for 10 [exposure to] 7) times. (The maximum stress, which the test piece can endure after repeated application of an external force).

Impact strength

The glass transition temperature (second order transition point) of PVC is over 70°C. The result is low impact strength at room temperature, which is one of the disadvantages of PVC. There are many ways to measure impact strength. Fig.6 shows the results of energies absorbed by test pieces when they are fixed and hammered to break (impact failure). Higher values show higher impact strength.