Shanghai, China – The use of fibre-reinforced epoxy plastic is limited by its brittleness and weak interlaminar properties. A group at Tonji University’s school of aerospace engineering and applied mechanics has been investigating the physical and mechanical properties of PU/epoxy interpenetration networks, and found that careful choice of PU can greatly improve these properties.
The group, led by Yiou Shen, used atomic force microscopy to show that even distribution of the appropriate amount of PU can improve the mechanical properties of the resin. This increases the strength and stiffness of the system. Macroscale tensile tests confirmed this.
They also found that if 15% by weight of PU is added to the epoxy, the initial fracture toughness of the composite is improved by 48%. Their conclusion was that PU/epoxy interpenetration networks have a positive effect on improving the interfacial and interlaminar properties of plant fibre-reinforced composites.
The work was published in the journal Polymer Composites.