Polystyrene waste‐modified epoxy/nanoclay and hybrid composite coatings

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In this study, bisphenol A-type epoxy (ER) and epoxy phenol novolac resins (EPN) with two amine-type curing agents (KH 816 and IPOX EH 2041) having different total amine values were selected. The mechanical properties and density of the EPN resin were found higher in the case of both curing agents. EPN was modified with polystyrene (EPN-PS) and used as a matrix using an IPOX hardener. Nano-and hybrid composites were prepared with pristine and modified with tetramethylammonium chloride nano montmorillonite (NC and MNC), and red mud waste (RMW). The chemical structure was elucidated by the Fourier transform infrared (FT-IR). The composites were characterized by scanning electron microscopy and x-ray diffraction. Appropriate PS and NC ratio was accepted as 4% and 2% by weight, respectively. Curing degrees calculated from the FT-IR spectra of ER, EPN, and EPN-PS were 99.3%, 99.9%, and 86.5%, respectively. A comparative study of the two binary systems; (i) 2 wt% NC-(15-35) wt% RMW; and (ii) 2 wt% of MNC-(15-35) wt% of RMW on the mechanical, thermal, and flammability properties of EPN-PS matrix was carried out. The appropriate RMW ratio was 30 wt%. Hybrid composites with 25-30 wt% RMW can be considered self-extinguishing materials.

Section: Resultsmentioning

confidence: 85%

Section: Methodsmentioning

confidence: 99%

“…The modified nanoclay (MNC) after washing with distilled water, was dried in an oven (60°C, 24 h). Detailed information was given in the previous study 20 …”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Red mud waste/nanoclay/polystyrene‐modified epoxy hybrid composites: Mechanical, thermal, and flammability properties

Özmeral

Soydal

Kocaman

et al. 2023

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Halogen‐free boron‐based hybrid system for enhancing flame retardancy, mechanical and thermal properties of epoxy

Kocaman,

Temiz,

Işık

et al. 2024

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This study aims to increase the flame retardancy of epoxy‐based composites by using various flame retardants together with colemanite filler (CLM), which is a very mineral‐rich boron type. As a flame retardant, aluminum hydroxide (Al(OH)3) and boron‐containing compounds: borax (BRX) and natural minerals (tincal (TNC) and colemanite (CLM)), as well as barium metaborate (BaMB) synthesized by us were used. Scanning electron microscopy (SEM), x‐ray powder diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), contact angle (CA), and particle size analysis were used to characterize the composites and additives. All boron compounds increased the thermal stability of the composites. Except for the ER/CLM‐BaMB composite, other composites' surface contact angles were over 90°. In terms of both combustion and thermal properties, the best CLM‐BaMB‐Al(OH)3‐TNC ratio was determined as 15:5:15:15. The tensile strength, self‐extinguishing time, estimated and experimental Limited Oxygen Index (LOI) values for this composite were determined as 96 MPa, 65 s, 29.6%, and 25%, respectively. In addition, ANOVA was applied to determine the effect of hybrid filler type and different weight ratios on the mechanical properties of composites.

The investigation of tribological properties of PAI/PI‐EPN polymer coating filled with WS₂ and SiC at low temperatures

Wang,

Cao,

Zhang

et al. 2024

To improve the tribological properties of polar crane copper alloy bearings to withstand wear under dry sliding wear and grease lubrication at low temperatures, three kinds of coating materials modified by incorporating WS2 and SiC into polyamide‐imide/polyimide‐phenolic epoxy resin were designed. These composite coatings were sprayed on the surfaces of CuPb22.5Sn2.5 copper alloys by liquid spraying technique. Firstly, the tribological experiments were performed with three different coatings. Then, nanoindentation testing and wear morphology analysis were conducted. The results show that the hardness of the composite coatings decreases with the increase of WS2. As the content of WS2 increases, the coefficients of friction (CoFs) of coatings decreases under dry sliding wear. The S2 coating filled with 7.5 wt% WS2 exhibits the lowest wear rate and the best wear resistance under low temperature and dry sliding wear. The coatings form a lubricating film on the worn surface under dry sliding wear at −70°C, improving the wear resistance of the coatings. The primary wear mechanisms are adhesive wear and fatigue wear. The wear rates of the coatings increase with the increasing content of WS2 under low‐temperature grease lubrication. The S1 coating filled with 5.0 wt% WS2 exhibits the lowest wear. The S1 coating demonstrates a CoF of 0.07 and a wear rate of 6.5 × 10−6 mm3N−1 m−1 at 0°C, showing excellent friction‐reducing and wear‐resistant properties. The primary wear mechanism is adhesive wear. The wear mechanisms of polymer coatings are closely related to temperature. The dominant wear mechanisms transfer from abrasive wear to adhesive wear and fatigue wear under dry sliding wear and decreasing temperature. The wear mechanisms transfer from predominantly adhesive and abrasive wear to adhesive wear, fatigue wear, and abrasive wear under grease lubrication. The hardness of the coatings and the behavior of the polymer at various low temperatures are the primary factors that affect the differing wear mechanisms.