PET interleaving veils for improved fracture toughness of glass fibre/low‐styrene‐emission unsaturated polyester resin composites

Abstract

The use of interleaved polyethylene terephthalate (PET) veils to increase the interlaminar fracture toughness of glass fiber-reinforced, low-styrene emission, unsaturated polyester resin composites, was investigated. PET, being chemically similar to the unsaturated polyester resin, was expected to exhibit good wetting and strong interaction with the matrix. Composite laminates were manufactured by hand lay-up, with the veil content varying up to 7%. The effects of PET veils on the interlaminar shear strength, flexural strength, flexural modulus, glass transition temperature, damping parameters, and Mode-I interlaminar fracture toughness of the composite were studied. The veils were found to enhance most of these properties, with only minor negative effects on flexural stiffness and T g . The PET/resin bonding did indeed prove to be strong, but the enhancement of fracture toughness was not as much as expected, because of the weaker glass/resin interface providing an alternative crack propagation path.

Effect of polyamide-6,6 (PA 66) nonwoven veils on the mechanical performance of carbon fiber/epoxy composites

“…They showed that PET veils had no significant effect on the IFT of composites while PA veils increased the mode I interlaminar fracture toughness values at crack initiation and propagation levels improved by 59 and 90%, respectively. Fitzmaurice et al [19] also showed that PET veils were not effective for improving Mode-I interlaminar fracture toughness of the glass fiber/ polyester resin (GF/ PE) composites due to the weaker glass/resin interface providing an alternative crack propagation path. They also showed that the incorporation of PET veils had positive effects on the flexural strength, interlaminar shear strength and damping properties of the composites.…”

“…Miller et al [22] observed a 40% increase in G IC with the addition of polyurethane (PU) veil. In all of these studies [18][19][20][21][22], the researchers investigated the effects of microfiber nonwoven veils on the fracture toughness of fiber reinforced composites, while other researchers went further and investigated the effects of electrospun nanofiber nonwoven veils on the delamination resistance of these composites. Although different types of nanofiber veils such as polyacrylonitrile (PAN) [23], polycaprolactone (PCL) [24] and polysulfone (PSF) [25] were studied in the literature, the majority of studies have focused on electrospun PA 66 nonwoven veils due to their high melting temperature (260°C), good compatibility with uncured resin and good mechanical properties [26].…”

Interleaving in Composites for High-Performance Structural Applications

“…Similarly, in another study conducted on GF/polyester composites, no significant effect on mode I ILFT was observed by PET interleave veils. 157 However, other mechanical properties such as flexural strength, ILSS, and damping resulted in improved values. Other microfiber veils of PU 134 and PA6,6 158 have exhibited positive increments in ILFT properties.…”

A new type of unsaturated polyester resin with epoxy functionalized nano‐silica and dimer fatty acid: Preparation and property

“…Unsaturated polyester resin (UPR) is widely used in the chemical industry, construction, transportation, electronics, and other fields because of its lightweight, high strength, corrosion resistance, and simple processing technology 1–5 . Due to the low toughness, poor thermal stability, and poor aging resistance of UPR, UPR usually needs to be modified for better comprehensive properties 6–9 . The most common method is to add functional fillers in UPR, such as nanoparticles, 10–12 fibers, 13–16 elastomer, 17,18 and vegetable oil 19–21 .…”