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1. OPTIMIZING MECHANICAL BEHAVIOR OF BASALT-NATURAL FIBER HYBRID INJECTION MOLDED COMPOSITES

   Kyleigh Rhodes, Bharath Nagaraja (May 2021, ANTEC)

   Society of Plastics Engineers (Ed.)

   Environmental consciousness is driving modern research and development in the automotive sector to target the advancement of feasible green materials in automotive applications. Basalt fiber has shown to be a robust competitor against glass and carbon fiber and is more eco-friendly manufacturing processes. Reinforcing polypropylene with basalt fiber and hemp hurd using maleic anhydride-grafted polypropylene (MAPP) as a coupling agent, has shown to contain similar mechanical properties to its competitors. A mixture model was implemented to optimize the mechanical properties of a variation of fiber ratios and MAPP to compare against a controlled GF mixture. Scanning Electron Microscope (SEM) analysis of fracture surfaces show the variation in fiber–matrix adhesion based on addition of MAPP. This study concludes that the addition of MAPP improves the mechanical behaviors of hybrid composites made from basalt fiber and hemp hurd reinforced polypropylene. 

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2. Mechanical and electrical properties of MWCNT/PP films and structural health monitoring of GF/PP joints

   Li, W.; Palardy, G. (November 2021, SPE Automotive Composites Conference & Exhibition)

   Online repository: https://speautomotive.com/acce-conference/2021-acce-papers-and-program-guides/ and also on: arXiv:2204.00909. Abstract: While welding of thermoplastic composites (TPCs) is a promising rivetless method to reduce weight, higher confidence in joints’ structural integrity and failure prediction must be achieved for widespread use in industry. In this work, we present an innovative study on damage detection for ultrasonically welded TPC joints with multi-walled carbon nanotubes (MWCNTs) and embedded buckypaper films. MWCNTs show promise for structural health monitoring (SHM) of composite joints, assembled by adhesive bonding or fusion bonding, through electrical resistance changes. This study focuses on investigating multifunctional films and their suitability for ultrasonic welding (USW) of TPCs, using two approaches: 1) MWCNT-filled polypropylene (PP) nanocomposites prepared via solvent dispersion, and 2) high conductivity MWCNT buckypaper embedded between PP films by hot pressing. Nanocomposite formulations containing 5 wt% and 10 wt% MWCNTs were synthesized using solvent dispersion method, followed by compression molding to manufacture films. The effect of MWCNT concentration on electrical and dynamic mechanical behavior of multifunctional films was examined with a Sourcemeter and Dynamic Mechanical Analyzer, and a comparison was made between 5 - 20 wt% MWCNT/PP films based on previous research. Glass fiber/polypropylene (GF/PP) composite joints were ultrasonically welded in a single lap shear configuration using buckypaper and MWCNT/PP films. Furthermore, electrical resistance measurements were carried out for joints under bending loads. It was observed that 15 wt% and 20 wt% MWCNT/PP films had higher stability and sensitivity for resistance response than embedded buckypaper and films with low MWCNT contents, demonstrating their suitability for USW and potential for SHM. 

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3. Study of Agave Fiber-Reinforced Biocomposite Films

   https://doi.org/10.3390/ma12010099  

   Annandarajah, Cindu; Li, Peng; Michel, Mitchel; Chen, Yuanfen; Jamshidi, Reihaneh; Kiziltas, Alper; Hoch, Richard; Grewell, David; Montazami, Reza (January 2019, Materials)

   Thermoplastic resins (linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polypropylene (PP)) reinforced by different content ratios of raw agave fibers were prepared and characterized in terms of their mechanical, thermal, and chemical properties as well as their morphology. The morphological properties of agave fibers and films were characterized by scanning electron microscopy and the variations in chemical interactions between the filler and matrix materials were studied using Fourier-transform infrared spectroscopy. No significant chemical interaction between the filler and matrix was observed. Melting point and crystallinity of the composites were evaluated for the effect of agave fiber on thermal properties of the composites, and modulus and yield strength parameters were inspected for mechanical analysis. While addition of natural fillers did not affect the overall thermal properties of the composite materials, elastic modulus and yielding stress exhibited direct correlation to the filler content and increased as the fiber content was increased. The highest elastic moduli were achieved with 20 wt % agave fiber for all the three composites. The values were increased by 319.3%, 69.2%, and 57.2%, for LLDPE, HDPE, and PP, respectively. The optimum yield stresses were achieved with 20 wt % fiber for LLDPE increasing by 84.2% and with 30 wt % for both HDPE and PP, increasing by 52% and 12.3% respectively. 

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4. A Versatile Strategy to Fabricate 3D Conductive Frameworks for Lithium Metal Anodes

   https://doi.org/10.1002/admi.201800807  

   Qi, Li‐Ya; Shang, Luoran; Chen, Xi; Ye, Luhan; Zhang, Weixia; Feng, Peijian; Zou, Wei; Cao, Naizhen; Zhou, Heng‐Hui; Weitz, David_A; et al (July 2018, Advanced Materials Interfaces)

   Abstract The suppression of lithium dendrite is critical to the realization of lithium metal batteries. 3D conductive framework, among different approaches, has shown very promising results in dendrite suppression. A novel cost‐effective and versatile dip‐coating method is presented here to make 3D conductive framework. Various substrates with different geometries are coated successfully with copper, including electrically insulating glass fiber (GF) or rice paper and conducting Ni foam. In particular, the as‐prepared copper coated GF shows promising results to serve as the lithium metal substrate by the electrochemical battery tests. The method significantly broadens the candidate materials database for 3D conductive framework to include all kinds of intrinsically insulating 3D substrates. 

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5. On the energy absorption in a novel CoFeSiB metallic‐glass fiber/epoxy resin composite under quasi‐static and dynamic compression conditions

   https://doi.org/10.1002/pc.28127  

   Liang, Weizhong; Wang, Longxing; Liaw, Peter K; Liu, Yingyi; Wei, Ransong; Xu, Jiawen (April 2024, Polymer Composites)

   Abstract Manufacturing and investigating metallic‐glass‐fiber‐reinforced epoxies is an important new attempt to present their potential to contribute to the aviation industry. In order to explore the energy absorption in novel CoFeSiB metallic‐glass‐fiber/epoxy resin composites, CoFeSiB/epoxy resin composite cylinders with different fiber volume fractions were prepared by a hot‐pressing method. The amorphism of the metal fibers was analyzed using x‐ray diffraction. The quasi‐static compression tests were performed on different fiber oriented samples with a diameter of 3.6 mm and a height of 7.2 mm. The sample with the fiber orientation [0°/90°] has a higher energy absorption capacity, compared to the one with the fiber orientation [0°/0°]. The dynamic‐ compression tests were performed on the [0°/0°] samples with a diameter of 3 mm and height of 6 mm at different air pressures. The compression fracture surfaces were examined by scanning electron microscope. Then the energy absorption mechanism of the composites was investigated. This study is of great significance for the energy absorption in amorphous metal fiber/epoxy composites. 

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