Bisphenol A based polyester binder as an effective interlaminar toughener

Toughening mechanisms responsible for excellent crack resistance in thermoplastic nanofiber reinforced epoxies through in-situ optical and scanning electron microscopy

“…A small amount of epoxy resin is applied to the veil using a syringe which subsequently wets out the nanofibers through wicking. Using a squeegee and a release foil (here vacuum bagging foil) the epoxy is applied evenly onto the nanofibrous veil after which pressure (here 40 kPa) and a temperature program (here 24 hours at 20°C, followed by 15 hours at 80°C, resulting Tg of 85 -90°C and approximate cross-link density of 1500 mol m -3 [39,40]) are applied for curing. This resulted in thin nanofiber modified epoxy films (here a nominal thickness of 100 µm).…”

“…Moreover, the obtained values of fracture energy are in close agreement with the strain energy release rate (fracture toughness) reported for the RIMR 135 resin system using standardized SENB specimens: a fracture toughness at crack initiation 𝐺 𝐼𝑐,𝑆𝐸𝑁𝐵 of around 1600 J m -2 is obtained in Refs. [14,39,45] for the non-modified virgin epoxy resin through experiments performed according to the ASTM D5045 procedure for determining the plane-strain fracture toughness and strain energy release rate of plastic materials. The crack initiation energy of virgin SENT specimens averages out at 1745 ± 170 J m -2 for the range of 𝑎/𝑊 tested here, and is indeed quite similar to the SENB result.…”

Improved fatigue delamination behaviour of composite laminates with electrospun thermoplastic nanofibrous interleaves using the Central Cut-Ply method

“…More details on the used VARTM process can be found in Ref. [36]. A total amount of 8 plies is used with the two middle plies cut prior to stacking.…”

Binders Used for the Manufacturing of Composite Materials by Liquid Composite Molding

“…At the same time if some precautions are taken in mind, interlaminar toughness of epoxy composites can be increased without negatively affecting other properties by coating the reinforcing plies with a bisphenol A-based thermoplastic polyester based on poly(4,4′-dipropoxy-2,2′-diphenylpropane fumarate) [ 50 , 51 ]. It was shown that by a proper selection of the amount of applied binder, the detrimental effects can be avoided and the mechanical properties can even be increased ( Table 4 ).…”