Performance Properties Of Composites Research Articles

Machine learning–enabled direct ink writing of conductive polymer composites for enhanced performance in thermal management and current protection

This study introduces a novel approach that leverages the synergy of machine learning (ML) and Direct Ink Writing (DIW) to optimize the manufacturing feasibility of conductive polymer composites (CPCs) films. The main research focus centers on precisely fine-tuning the printing parameters to strike the perfect balance between the high loading of dendritic copper fillers and their influences on processing and composite performance properties. This pioneering combination significantly enhances the precision of the final product without resorting to time-consuming procedures. ML algorithms contributed to identifying optimal printing variables such as speed, flow pressure, and filler concentration, which helped in identifying the optimal filler content and its performance capabilities. The resulting films exhibited thermo-resistive behavior with a noticeable resistivity increase by 6-7 orders of magnitude at elevated temperatures, specifically around 100 °C. Furthermore, the study highlights remarkable strain-sensing capabilities, simultaneously showcasing a substantial increase in composite modulus. These discoveries bear substantial significance for the development of exceptionally functional thermal interface materials suitable for use in sensors, current collectors, and energy storage devices. The method presented here offers a promising pathway for advancing the fabrication and performance optimization of conductive polymer composites, opening up diverse applications in emerging technologies.

Эксплуатационные характеристики древесно-полимерных композитов на основе ацетилированного древесного наполнителя

The demand for composite materials is growing every year. In this regard, the competitiveness of a particular product is determined primarily by the price-quality ratio. The most rational option for the production of wood-filled composites is using the materials with the increased performance characteristics. To date, it is the performance characteristics of modern composite materials that are the most significant, not only for final consumers, but also for manufacturers. In this regard, to improve performance characteristics in the production of wood-filled composites, various methods of pre-treatment of wood are used – thermal modification, acetylation, furfulation, ultra-high-frequency processing, alkali treatment, the use of various additives, etc. A promising way to improve the physical and mechanical properties of wood-filled materials is acetylation, whose mechanism consists in the formation of acetyl groups in wood during processing. To reduce production costs and the cost of the final product, it is possible to use a cheaper precursor (for example, icy acetic acid instead of acetic anhydride) with the possibility of intensifying the impregnation process. This article presents the results of obtaining wood-filled composites based on acetylated birch wood flour with its various proportions in the composition. The effect of introducing acetylated wood filler into the composition on the performance properties of composites (abradability, frost-resistance, flexural strength) has been evaluated in comparison with control samples made from untreated birch wood flour. The effect of acetylation with glacial acetic acid on the structure of birch wood flour has been characterized using Fourier-transform infrared spectroscopy. The IR-spectra of the control and acetylated samples contain absorption bands belonging to the corresponding groups of cellulose and lignin of hardwoods. The abradability and frost-resistance coefficients for a wood-filled composite based on acetylated birch wood flour are on average 1.5–2 times lower for all compositions compared to control samples. The results of the research allow us to conclude that acetylation of wood flour as a method of pre-treatment of the filler in order to improve the performance characteristics of the final product is promising for implementation in the production of wood-filled materials.

Service properties of composite electrochemical coating

The article considers the ways of solving problems, regarding the rework and durability improvement of elements of industrial equipment. One of the ways to restore and improve the operational properties of machinery parts is the application of galvanic coatings, in particular, composite galvanic coatings. The article shows ways to improve the performance properties of composites, determines the optimal content of the dispersed phase in the composite, in terms of the ratio of the strength of the dispersed phase and matrix. The composite electrochemical coating wear resistance and the roughness of composites under conditions of abrasive wear have been explored. The relationship between the wear resistance and the surface roughness during wear has been determined. In an experimental study of the composite coatings abrasive wear resistance, it was found that their wear largely depends on the size and volume content of dispersed particles in the coating. It has been experimentally proven that the composite coating roughness depends on the matrix mechanical properties, the content and size of disperse particles.

Long term performance study of glass reinforced composites with different resins under marine environment

For marine structural applications which poses significant challenges to the choice of materials due to presence of corrosive seawater, polymer matrix based fiber reinforced composites are increasingly becoming the material of choice. However the performance properties of composites are greatly influenced by the moisture absorbed by the composite. In the current study, the long term performance is assessed by determining the amount of moisture absorbed and the reduction of mechanical properties over 12 months in a simulated sea-water environment at different temperatures. Three commonly used thermoset resins with different chemistry such as unsaturated polyester (USP), epoxy resin (EP) and vinylester (VE) are chosen. The effect of fiber reinforcement on the long term performance is investigated. A suitable method for manufacturing glass reinforced composite with good interfacial bonding and high volume fraction is also developed in current study. It is observed that vinylester plaques and composites absorb lesser moisture compared to USP and Epoxy systems resulting in lesser reduction in flexural strength and making the best performing among polymers studied. It is also found that sea-water diffusion into the composite follows non-Fickian behaviour and diffusion relaxation model fits well with the experimental data and corresponding model parameters are evaluated.

Optimization of surface treatment to enhance fiber–matrix interface and performance of composites

Oxidation treatment with concentrated HNO3 was employed to the carbon fabric (CF) for various time intervals (30–180min) to observe the effect of treatment on two simultaneous processes involved viz. improvement in its adhesion with the matrix and reduction of fiber strength which in turn is responsible for change in the performance properties of composites. Seven composites with untreated and acid treated CF were developed based on the polyetherimide (PEI) matrix and evaluated for adhesive wear properties under various loads (200–600N) against mild steel disc. 90min treated CF composite indicated the best tribological properties and showed 30% reduction in specific wear rate (K0) and 23% in coefficient of friction (μ) respectively at 600N load. Treatment beyond this time proved detrimental for improvement in properties. Field emission scanning electron microscopy (FE-SEM) showed increase in roughness with treatment time, while atomic force microscopy (AFM) studies indicated substantial increase in roughness value. Scanning electron microscopy (SEM) of worn surfaces supported the wear mechanisms and improvement in adhesion between fiber and matrix.

Advanced Wood- and Bio-Composites: Enhanced Performance and Sustainability

Use of wood-based-composites technology to create value-added commodities and traditional construction materials is generally accepted worldwide. Engineered wood- and lignocellulosiccomposite technologies allow users to add considerable value to a diverse number of wood- and lignocellulosic feedstocks including small-diameter timber, fast plantation-grown timber, agricultural fibre and lignocellulosic residues, exotic-invasive species, recycled lumber, and timber removals of hazardous forest-fuels. Another potential advantage of this type of economic- and materials-development scenario is that developing industrial composite processing technologies will provide producers an ability to use, and to adapt with, an ever-changing quality level of wood and/or other natural lignocellulosic feedstocks. However, the current level of performance of our state-of-the-art engineered composite products sometimes limit broader application into commercial, non-residential and industrial construction markets because of both real and perceived issues related to fire, structural-performance, and service-life. The worldwide research community has recognized this and is currently addressing each of these issues. From a performance standpoint, this developing knowledge has already and will continue to provide the fundamental understanding required to manufacture advanced engineered composites. From a manufacturing and a resource sustainability standpoint, with this evolving fundamental understanding of the relationships between materials, processes, and composite performance properties we now can in some cases, or may soon be able to, recognize the attributes and quality of an array of bio-based materials then adjust the composite manufacturing process to produce high-performance composite products. As this fundamental understanding is developed, we will increasingly be able to produce advanced, high-performance wood- and bio-composites. Then we must use those technologies as tools to help forest and land managers fund efforts to restore damaged eco-systems and which in turn may further promote sustainable forest management practices.