This chart compares the "Coefficient of linear thermal expansion" shown as a factor m/m.k in the table. All materials expand with changes in Temperature. Thermoplastics expand considerably more than metals (e.g. Carbon Steel 10.8 (10)-6 compared to UHMWPE 200 (10)-6 i.e. approximately 18 times more).

Linear thermal expansion means the product will expand in all directions and this needs to be allowed for in design calculations. The calculation is: (given factor) x 10-6 x length x change in temperature °C.