Search

Highlights Ultrasonic methods are more sensitive to defects such as voids, pores, and discontinuities that can diminish the true elastic and acoustic properties of materials compared to destructive testing. Therefore, the elastic properties and some acoustic properties of the epoxy phenol novolac modified with polystyrene (EPN‐PS) matrix‐based nano‐ and hybrid composites were determined for the first time using ultrasonic method. Montmorillonite‐type nanoclay (NC) and industrial red mud waste (RMW) at a rate of 1–4 and 15–35 wt% respectively, were used as fillers in the composite preparation. According to the results, the highest elastic coefficient values (L = 8.14 GPa, G = 1.76 GPa, K = 5.79 GPa and E = 4.80 GPa) were obtained in the EPN‐PS/NC1 (with 1 wt% NC) nanocomposite sample compared to the elastic properties of pure EPN and EPN‐PS, while the highest elastic coefficient values (L = 8.97 GPa, G = 2.19 GPa, K = 6.06 GPa, and E = 5.86 GPa) among hybrid composites (HC) were obtained for the HC35 containing 2 wt. % NC and 35 wt% RMW. Due to both its high elastic and good acoustic properties, wall panels and floors produced using HC35 hybrid composite can be used for sound insulation in noisy environments. First evaluation of the acoustic characteristics of epoxy phenol novolac modified with polystyrene‐nanoclay/red mud waste (EPN‐PS‐NC/RMW) composites. NC4 with 4 wt% nanoclay showed the lowest elastic and acoustic properties. Nanoclay ratio above 1 wt% reduces elastic and acoustic properties. The increasing RMW ratio in hybrid composites increases elastic properties. High elastic and acoustic properties make HC35 ideal for sound insulation. [ABSTRACT FROM AUTHOR]

In this paper two waste fillers, namely ground tire rubber (GTR) and coffee silverskin (CSS, a waste bio‐product from the coffee‐making process), have been used to produce sustainable ethylene‐propylene‐diene monomer (EPDM) rubber compounds vulcanized on steel sheets to fabricate rubber‐to‐steel bonded systems for industrial roofing applications. The compounds have shown good mechanical performances, with elastic moduli in the range of 13–16 MPa, tensile strength of 13–20 MPa and elongation at break >400%, and strong adhesion to the metal substrate. Moreover, the rubber‐to‐steel bonded systems present good sound insulation properties (mean sound transmission loss [STL] of 39 dB and noise level reduction in simulated hailstones impact tests of 62 dB with respect to bare steel 73 dB). Accelerated UV‐ and thermal‐aging tests have shown excellent adhesion of the compounds to the metal substrate with the CSS acting as an antioxidant agent preventing excessive polymer degradation. The selected waste‐derived materials result in promising fillers for more sustainable rubber compounds. Highlights: Waste fillers were used to produce sustainable rubber compounds.Rubber‐to‐steel bonded systems for roofing applications were produced.Rubber‐to‐steel bonded systems have good sound insulation properties.Rubber‐to‐steel bonded systems have excellent adhesion.Coffee silverskin filler acts as an antioxidant agent. [ABSTRACT FROM AUTHOR]

Honeycomb composite with excellent mechanical–physical properties had attracted extensive attention. To achieve outstanding sound insulation while maximizing the high‐performance of honeycomb composite, this article reported a honeycomb composite structure filled with glass fiber (HFG) based on a paper‐making process and the corresponding sandwich structure. Pulping parameters, mechanical property, air permeability and sound insulation of HFG were analyzed. The results showed that the hanging index and settling height of glass fiber slurry were inversely proportional to the beating degree, which was beneficial for reducing the coefficient of variation (CV) of HFG with value of 4%–6%. The maximum improvement in tensile strength and bursting strength of HFG were 70% and 53%, respectively. In addition, sound transmission loss (STL) of HFG was proportional to cell size, density, filling amount and thickness of the honeycomb. Compared to HFG, sandwich structure consisting of HFG and glass fiber/hot melt fiber panels effectively improved STL, especially at low‐mid frequencies. It was also found that designing holes on the surface of sandwich structure could further improve STL in certain frequency bands. The structure offered a lightweight and high‐performance response for construction, transportation and infrastructure. Highlights: This article designs a new type of honeycomb filled glass fiber via paper‐making process, aiming to improve the comprehensive performance of honeycomb.By the design of embedded structure, the maximum improvement in tensile strength and bursting strength of honeycomb were 70% and 53%, respectively.By designing perforated, embedded and laminated structures, sound insulation has been improved, while reducing material quality. [ABSTRACT FROM AUTHOR]

Environmental concerns of disposals of automotive, building, or packaging applications enforce researchers to find alternative green materials. Hybrid biocomposites, which consists of both natural/man‐made fibers and biopolymers, can be an alternative to glass fiber‐supported composites. On the other hand, heat and sound insulation are key properties for automotive and building industries and there is limited knowledge about insulation properties of biocomposites. In this study, we produced basalt/beech wood fiber reinforced polylactic acid (PLA) biocomposites by twin‐screw extruder, followed by compression molding. We investigated sound and heat insulation properties as well as mechanical and physical properties. Thermogravimetric analysis, Fourier transform infrared and scanning electron microscopy analyses were carried out for thermal, chemical, and morphological characterization of biocomposites, respectively. Analysis revealed that basalt/wood fiber support improved heat and sound insulation of biocomposites; however, water absorption properties reduced by natural fiber loading. Besides, both tensile and flexural strength of the biocomposites reduced by increasing natural fiber loading. [ABSTRACT FROM AUTHOR]

Glass fiber fabric‐reinforced epoxy composites (GEC) have some weakness on both thermal insulation and sound absorption insulation, which are very important for many application areas such as aircraft, train, and so on. The main aim of this study is to improve both sound absorbent and thermal insulation properties of GEC by incorporating different fillers such as hollow glass microspheres (HGMs), polystyrene (PS) microfiber membrane, and PS solution. Results show that incorporation of PS solution into glass fiber fabric epoxy composite (GEC‐PS) provides higher sound absorption coefficient leading to an increase in the max SAC value from 0.1 to 0.4 and improvement in thermal insulation by decrease of thermal conductivity coefficient of GEC from 0.48 to 0.448 W/mK. Thermal insulation properties of GEC were improved by the use of PS microfiber membrane, which decreases the thermal conductivity coefficient of GEC from 0.48 to 0.438 W/mK. HGM did not improve both the thermal insulation and sound absorption insulation properties of GEC due to the agglomeration. [ABSTRACT FROM AUTHOR]

A new kind of co‐cured sandwich composite was manufactured via inserting tailored damping materials between the lamina to enhance vibration characteristics and sound insulation performance of traditional sandwich composite. The sandwich material was investigated based on the theory of co‐curing, which was superior to the preparation process of traditional sandwich composite. The viscous flow characteristics of epoxy resin and rubber sandwich were considered in the preparation process. The damping characteristics and sound insulation properties of the sandwich composite were determined by the single cantilever beam vibration test and the standing wave tube method. The loss factor of the sandwich composites with damping layer thickness of 0.1 mm reaches 3.384%, which increases by 102.81% compared with that of the undamped composite. The experimental results reveal that the novel damping polymer enhances the damping characteristic and sound insulation performance of laminates significantly compared with previous sandwich composite. The conclusion indicates that the co‐cured composite structures show a strong ability of vibration reduction and sound insulation. [ABSTRACT FROM AUTHOR]

Dense mineral fillers are used to provide sound insulation properties to polymer‐matrix composites. According to the mass law of sound insulation, the greater the mass, the harder it is for the material to vibrate, indicating the material will have better insulation. Thus, magnetite and barite minerals provide sound insulation by adding weight to composites. In this study, 25% (w) dense filler and 75% (w) acrylonitrile butadiene styrene (ABS) composites were prepared using a laboratory‐type twin‐screw extruder. Dense filler powders and ABS/dense filler composites were characterized using a particle size analyzer, a color spectrophotometer, a gas pycnometer, an X‐ray diffractometer, a Fourier transform infrared spectrometer, an impedance tube, and techniques such as the Brunauer Emmett Teller method and high‐resolution microtomography (μ‐CT). The sound insulation of ABS blend with these two minerals as fillers was compared. Magnetite had better sound insulation performance although both fillers were incorporated into the polymers in equal amounts by weight. The better sound insulation performance of magnetite was attributed to its good dispersion in the polymer matrix. The dispersion of the filler particles within the composites was displayed in three dimensions utilizing X‐ray μ‐CT. Structural analysis was performed on the tomography images, and numerical values expressing the dispersion quality of the filler particles in the composites were obtained. [ABSTRACT FROM AUTHOR]

In this study, nonwoven fabrics were coated with ethylene vinyl acetate/hematite blends. Three different hematite loadings (100, 300, and 600 g/m2) were applied. After evaluations of morphology, thermal stability, and mechanical properties of the coated structures, sound insulation property was investigated. In addition, a detailed statistical analysis was performed on sound transmission loss. It was found that sound insulation property changed depending on the frequency and hematite loading amount. A hematite loading amount of 160–190 g/m2 can be used together with ethylene vinyl acetate as the matrix polymer for enhanced thermal and sound insulation properties without compromising mechanical performance. POLYM. COMPOS., 40:1890–1896, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]