Surface energetics, adhesion, and adhesive joints. III. Surface tension of molten polyethylene

Abstract
The surface tension of polyethylene has been measured by the ring method over the temperature range 125–193°C. Because of problems with the viscousness of the liquid polyethylene, it was found convenient to use an Instron testing apparatus instead of the usual du Nouy torsion balance. The surface tension of the polyethylene decreased from a value of 28.5 dynes/cm. at 125°C. to 23.3 dynes/cm. at 193°C. with an average temperature coefficient of −0.076 dynes/cm./°C.