Improvement of interlaminar fracture toughness of phenolic laminates interleaved with electrospun polyvinyl butyral nanofibers

Abstract

Among different types of composites, laminated composites are those may be delaminated under applied loads. Phenolic resin/Glass fiber composite is one of the most widely used composites, however, it is susceptible to delamination very likely that it will delaminate. In this research, polyvinyl butyral (PVB) electrospun nanowebs have been used as the interlayer to toughen phenolic resin/glass fiber composites. In order to evaluate the effect of main factors on the fracture toughness of the laminates, interlayer dimensional parameters such as interlayer thickness (30, 90 and 150 µm), nanofiber diameter (200 and 500 nm) and nanofiber orientation (random and aligned) were investigated in Mode I and Mode II fractures. The surface response method (RSM) was used to find the optimal diameter of PVB electrospun nanofibers. The results showed that the thickness of the interlayer is the most effective factor in improving the composite toughness in Mode I and Mode II. The thickness of 30 μm showed the best result in Mode I and Mode II and increased GIc and GIIc values by 70% and 38%, respectively. Also, with decreasing the nanofibers diameter and increasing the collision level, the amount of energy absorbed from the crack increases and results in to improvement of the fracture toughness. Nanofiber alignment showed less effect on the composite fracture compared to other factors.