Effects of graphene nano-platelets size and content on tensile properties of polypropylene composites at higher tension rate

The influence of graphene nano-platelets size and content on tensile properties of polypropylene composites was investigated by means of a universal testing machine under room temperature and tension rate 300 mm/min. The results showed that the Young’s modulus increased with increasing graphene nano-platelets weight fraction, the tensile yield strength and the tensile fracture strength increased when graphene nano-platelets weight fraction was lower than 0.4 wt.%, and then varied slightly with increasing graphene nano-platelets weight fraction; while the tensile elongation at break decreased with increasing graphene nano-platelets weight fraction. In addition, the difference in tensile yield strength, tensile fracture strength, and tensile elongation at break between the composites reinforced separately with different size graphene nano-platelets was not significant under these experimental conditions; this could be attributed to the interfacial layer between the filler and the matrix could transfer some stress under tensile load.

Structure and Properties of Irradiation Crosslinked UHMWPE

Irradiation crosslinking is one of the most important methods to modify UHMWPE, it can effectively improve the hardness, creep resistance and abrasion resistance of this material. In order to eliminate free radical, increase material strength, abrasion resistance and fatigue resistance of creep, this study uses Co60-γ to modify UHMWPE under vacuum atmosphere, with the irradiation dose of 30, 60, 90, 120 Kgy respectively. Its mechanical properties, microstructure, degree of crosslinking and crystallinity are analyzed, the results show that the modified UHMWPEs impact strength decreased, elongation basically remain unchanged, tensile fracture strength and tensile yield strength increased.