Mechanical and nanomechanical properties of MWCNT/PP nanocomposite

The mechanical and nanomechanical properties of multi-walled carbon nanotube-reinforced polypropylene (MWCNT/PP) nanocomposite were investigated through tension tests (conducted on 2 wt% and 5 wt% specimens) and nanoindentation tests (conducted on 2 wt% specimens). In addition, the structural properties and topography of the nanocomposite were characterized by means of scanning electron microscopy (SEM) and Scanning Probe Microscopy (SPM), respectively. The results from the tension tests reveal an enhancement and a considerable scatter in the Young’s modulus and maximum stress of the MWCNT/PP nanocomposite for both MWCNT content. For the specimens with mechanical properties lower than the average values, the SEM and SPM images revealed poor dispersion and formation of large agglomerates. The hardness (as resistance to applied load) and Young’s modulus were mapped at 300 nm of displacement, for a grid of 70 ´ 70 μm2. Through projection, the resistance is clearly divided into 3 regions, namely the PP matrix, the interphase (region close to/between MWCNTs) and the regions of the MWCNT agglomerates. The resistance deviates from low values (few MPas) to 1.8 GPa. The present experimental study provides all necessary data for the model creation and validation of the MWCNT/PP nanocomposite

Mechanical and nanomechanical properties of MWCNT/PP nanocomposite

The mechanical and nanomechanical properties of multi-walled carbon nanotube-reinforced polypropylene (MWCNT/PP) nanocomposite were investigated through tension tests (conducted on 2 wt% and 5 wt% specimens) and nanoindentation tests (conducted on 2 wt% specimens). In addition, the structural properties and topography of the nanocomposite were characterized by means of scanning electron microscopy (SEM) and Scanning Probe Microscopy (SPM), respectively. The results from the tension tests reveal an enhancement and a considerable scatter in the Youngs modulus and maximum stress of the MWCNT/PP nanocomposite for both MWCNT content. For the specimens with mechanical properties lower than the average values, the SEM and SPM images revealed poor dispersion and formation of large agglomerates. The hardness (as resistance to applied load) and Young蒒s modulus were mapped at 300 nm of displacement, for a grid of 70 ( 70 �m2. Through projection, the resistance is clearly divided into 3 regions, namely the PP matrix, the interphase (region close to/between MWCNTs) and the regions of the MWCNT agglomerates. The resistance deviates from low values (few MPa) to 1.8 GPa. The present experimental study provides all necessary data for the model creation and validation of the MWCNT/PP nanocomposite

A multi-technique and multi-scale analysis of the thermal degradation of PEEK in laser heating

Data availability: Data will be made available on request.Copyright © 2023 The Author(s). The present work studies the thermal degradation of laser-heated poly-ether-ether-ketone (PEEK) as the heating duration increases. Its damage morphology, chemical composition, crystallinity content, and mechanical properties are examined with optical microscopy, attenuated total reflection-Fourier transform infrared spectroscopy, differential scanning calorimetry, Raman spectroscopy, and continuous stiffness measurement nanoindentation. The applicability of those methods in detecting the thermal degradation of laser-heated PEEK and assessing the induced thermal damage is highlighted. Results show that short-time laser heating acts as an annealing process that improves the crystallinity and hardness on the affected surface of PEEK by up to 5.1% and 10.8% respectively. With a further increase in the heating duration, surface carbonisation occurs and a char layer is formed. Surface carbonisation is associated with the thermal limits of PEEK in laser heating decreasing by up to 50% its hardness and by 45% its indentation modulus. Finally, the char layer is found to act as a shielding mechanism that protects the bulk PEEK from the applied thermal load, resulting in mostly superficial thermally induced damage.This publication was made possible by the sponsorship and support of TWI. The work was enabled through, and undertaken at, the National Structural Integrity Research Centre (NSIRC), a postgraduate engineering facility for industry-led research into structural integrity established and managed by TWI through a network of both national and international Universities. Dimitrios Gaitanelis and Dr Angeliki Chanteli would like to thank Young European Research Universities Network (YERUN) for being awarded the YERUN Research Mobility Award 2021 to proceed to this collaboration. Dr Angeliki Chanteli and Professor Paul M. Weaver would like to thank Science Foundation Ireland (SFI) for funding Spatially and Temporally VARIable COMPosite Structures (VARICOMP) Grant No. (15/RP/2773) under its Research Professor programme