Toward tailoring the mechanical and dielectric properties of short glass fiber‐reinforced epoxy composites

We designed three‐dimensional (3D) structures through a combination of glass fiber cloth and in situ formation of nano polyphenylene oxide (PPE) fibers during the fabrication process of thermosetting cyanate ester/bismaleimide composites and developed a self‐stitching technique based on PPE fiber and interpenetrating polymer networks (IPNs) for aiding the crack self‐healing. The building of 3D structure effectively improves the interface interaction between fiber and matrix and suppresses the crack propagation process in composite, leading to significant enhancement in the mechanical properties. When PPE content is 20%, the interlaminar shear strength, flexural strength, impact strength, and tensile strength of the resulting composite are 98%, 74%, 95%, and 101% higher than those of the composite without PPE. The resulting composites possess excellent thermomechanical and lower dielectric properties. Because IPNs within composites can create interspaces and easily deform above glass‐transition temperature, PPE components may penetrate through the interspaces under thermal expansion force, and the contraction stresses of polymers generate strong locking effects in composite after cooling to room temperature, then the crack surfaces of composites can be stitched by PPE fibers, significantly recovering the mechanical properties. The healing efficiency of the composite with 30% PPE after impact and then heating at approximately 280°C can reach 96%.Highlights 3D structures were constructed during the fabrication process of glass‐fiber‐reinforced thermosetting cyanate ester/bismaleimide composite. A self‐stitching technique was developed for aiding the crack self‐healing of composite. 3D structures significantly improved the interface interaction between fiber and matrix in laminated composite. The mechanical properties of the resulting composite could be significantly improved by 3D structures. The healing efficiency of the healed composite could reach 96%.

“…Evidently, the as-prepared GFBTnPPE composites have desirable dielectric properties compared to GFBT composites and can be used to prepare radomes, electrical insulators, etc. 77…”

Section: Dielectric Properties Of Gfbtnppe Compositementioning

confidence: 99%

Designing a 3D structure and a self‐healing technique for advanced polymer composites with outstanding mechanical properties and healing ability

Yuan,

Pan,

Liang

et al. 2023

“…Epoxy resin (EP) is a widely employed thermosetting polymer material 9–11 . Thus, the modification of EP has been addressed extensively, such as adding functional particles to improve the thermal conductivity, 12 electrical conductivity 13 and flame resistance, 14,15 adding CNTs, 16 nano‐clays, 17,18 inorganic alumina, 19,20 graphene oxide, 21–23 functionalized aramid nanofibers (fANFs), 24,25 pyrolyzed carbon black, 26 and other hybrid fillers 27,28 to enhance its comprehensive mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Fully aminated rigid‐rod aromatic polyamide efficiently reinforces tetraglycidyl diamino diphenyl methane epoxy resin and its carbon fiber composite

Wang,

Peng,

Wang

et al. 2024

Tetraglycidyl diamino diphenyl methane (TGDDM) and its carbon fiber composite are widely studied and used because of their heat resistance and high performance. In order to obtain efficient reinforcing effects in a simple manner, we adopt the idea of molecular composite—uniformly dispersing the rigid‐rod macromolecules in the TGDDM matrix. Herein, we prepared fully aminated‐poly(p‐phenylene terephthalamide) by direct polycondensation and hydrogenation reduction as the reinforcing agent. The fully aminated‐PPTA is distributed uniformly in the cross‐linked epoxy resin (EP) network by chemical bonds, and achieves efficient reinforcement. With the addition of only 0.5 wt% fully aminated‐PPTA, the tensile strength and Young's modulus of EP are improved to 127.7 ± 7.4 MPa (+28%) and 3.36 ± 0.15 GPa (+44%); the flexural strength and modulus are improved to 209.6 ± 9.4 MPa (+42%) and 3.70 ± 0.14 GPa (+37%); the notch impact strength is improved by 32%. Crucially, the heat resistance of EP almost remains unchanged. Furthermore, the flexural properties and interlaminar shear strength of the carbon fiber composite are also comprehensively increased. Compared with other modified fillers, the fully aminated‐PPTA is simple to prepare and blend, and is an efficient reinforcing agent for TGDDM and its carbon fiber composite benefitting from its rigid‐rod main chain and amino side groups.Highlights Molecular composite can achieve excellent strengthen and toughen effects. Fully aminated‐PPTA is embedded uniformly in EP network by chemical bonds. TGDDM is effectively reinforced without deteriorated heat resistance. Fully aminated‐PPTA is also a comprehensive reinforcement for EP/CF composite.

High performance poly(ethylene‐co‐vinyl acetate)/nickel oxide nanocomposite prepared through open mill mixing technique for energy storage applications

Shini,

Arun,

Ramesan

2024

Polymer nanocomposite films of poly(ethylene‐co‐vinyl acetate) (EVA) with different concentrations of nickel oxide (NiO) nanoparticles (NPs), produced by an open two‐roll mill mixing method. Structural characterization using Fourier transform infrared (FTIR), UV–visible spectroscopic studies and x‐ray diffraction (XRD) analysis showed elevated peak intensity for composites confirming good polymer‐filler interaction, optical clarity and improved crystallinity. Morphological analysis by field emission scanning electron microscopy (FE‐SEM) and high‐resolution transmission electron microscopy (HR‐TEM) revealed the structural regularity of nanocomposites (NCs). Augmented thermal stability, evident from thermogravimetric analysis (TGA) with increased decomposition temperature was corroborated by an increase in glass transition temperature (Tg) detected through differential scanning calorimetry (DSC) analysis. Dielectric constant and alternating current (AC) conductivity values increased with temperature, filler content and frequency. Composites containing 7 wt% NiO showed significant enhancements in mechanical properties compared to EVA, with tensile strength increasing by 122%, tear strength by 179.9%, and impact strength by 111.9%. EVA/10 wt% NiO composite exhibited the highest hardness increase of 11.9%, while elongation at break decreased by 8% for the same composition. The experimental results suggest that EVA/NiO nanocomposite films can be employed as promising alternatives for flexible dielectric substrates for optoelectronic devices.Highlights A series of EVA/NiO NCs were prepared and characterized. Enhanced optical property, thermal stability and Tg. Possess excellent electrical properties. Mechanical strength and impact resistance of EVA was greatly enhanced. A promising material for flexible energy storage applications.