Hydroxyl terminated poly(ether ether ketone) with pendant methyl group-toughened epoxy clay ternary nanocomposites: Preparation, morphology, and thermomechanical properties

Experimental and Numerical Investigation of Tensile and Flexural Behavior of Nanoclay Wood-Plastic Composite

In this study, the effect of wood powder and nanoclay particle content on composites’ mechanical behavior made with polyethylene matrix has been investigated. The wood flour as a reinforcer made of wood powder was at levels of 30, 40, and 50 wt.%, and additional reinforcement with nanoclay at 0, 1, 3, and 5 wt.%. Furthermore, to make a composite matrix, high-density polyethylene was used at levels of 70, 60, and 50% by weight. Wood-plastic composite (WPC) specimens were manufactured in injection molding. After preparing the specimens, tensile and bending tests were performed on samples. The mechanical properties such as tensile and flexural strength and flexural modulus were measured. Results showed that nanoclay particle content increases flexural modulus, flexural strength, modulus of elasticity, and tensile strength. The experimental test results show that Young’s moduli increased with the volume of wood flour. The biggest modulus of elasticity was achieved in the samples having 50 wt.% of wood powder. Furthermore, the highest value of tensile strength was achieved at the level of 30 wt.%. The highest flexural strength was for the sample containing 50% wood powder by weight. Additionally, a numerical model was made utilizing the Abaqus software using the finite element method (FEM). Comparing the numerical and experimental results, it was found that they are compatible in the linear-elastic and plastic state of the material. There are no crucial differences between experiment and FEM.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

Preparation, morphology and thermo-mechanical properties of epoxy resins modified by co-poly (phthalazinone ether sulfone)

A series of blends were prepared by adding a novel thermoplastic co-poly (phthalazinone ether sulfone) (PPBES) in varying proportions to diglycidyl ether of bisphenol A epoxy resin (DGEBA) cured with p-diaminodiphenylsulfone. The microstructure and thermo-mechanical properties were investigated as a function of the concentration of PPBES and curing conditions. The thermal properties, measured by differential scanning calorimetry and thermogravimetric analysis showed that PPBES could enhance the glass transition temperature (Tg) of the DGEBA epoxy resin and retain its thermal stability. The microstructure changed from sea-island to phase-inverted structure with the various concentrations of PPBES. The fracture toughness, expressed as notched impact strength, increased with the addition of PPBES and made the maximum value with 15-phr PPBES. Fracture mechanisms such as crack deflection and branches, ductile microcracks, ductile tearing of the thermoplastic was responsible for the increase in the fracture toughness of the blends.