Research Progress on Sound Absorption of Electrospun Fibrous Composite Materials

Noise is considered severe environmental pollutant that affects human health. Using sound absorption materials to reduce noise is a way to decrease the hazards of noise pollution. Micro/nanofibers have advantages in sound absorption due to their properties such as small diameter, large specific surface area, and high porosity. Electrospinning is a technology for producing micro/nanofibers, and this technology has attracted interest in the field of sound absorption. To broaden the applications of electrospun micro/nanofibers in acoustics, the present study of electrospun micro/nano fibrous materials for sound absorption is summarized. First, the factors affecting the micro/nanofibers' sound absorption properties in the process of electrospinning are presented. Through changing the materials, process parameters, and duration of electrospinning, the properties, morphologies, and thicknesses of electrospun micro/nanofibers can be controlled. Hence, the sound absorption characteristics of electrospun micro/nanofibers will be affected. Second, the studies on porous sound absorbers, combined with electrospun micro/nanofibers, are introduced. Then, the studies of electrospun micro/nanofibers in resonant sound absorption are concluded. Finally, the shortcomings of electrospun micro/nano fibrous sound absorption materials are discussed, and the future research is forecasted.

Synthesis and performance evaluation of plastic waste aerogel as sustainable and reusable oil absorbent

Direct utilization of waste polyethylene terephthalate (PET) from the environment to form highly porous aerogel technology for oil absorption is an attractive approach from the view point of green chemistry. However, the oil absorption reaction is limited by low oil absorption capacity and less stability. For now, silica aerogel are used to solve these problem. Our goal is to substitute to these silica aerogel with PET aerogel technology. Herein, we have prepared an environmental waste PET based aerogel with 1.0:0.5 wt% PET, polyvinyl alcohol (PVA), and glutaraldehyde (GA) 0.2% v/v were dispersed in 10 mL DI water, followed by homogenization (30 min), sonication (10 min), and ageing (2 h) at 70 °C. To escape macroscopic cracking, cooling (8 h) at 4 °C was followed by freezing (6 h), freeze drying at -80 °C, and 5 mTorr for 18 h. The hybrid PET aerogel displays excellent performance towards oil absorption. Notably it showed high absorption capacity towards the different oils about 21-40 times its own weight, depending on the viscosity and density of the oil and solvents within 15-35 s, 25 °C, and 2 × 2 cm aerogel size. In addition, the aerogel shows there is no change in structure after several recycles due to high mechanical strength. Furthermore, because of the PET aerogel's high porosity (99.74%) and low density (0.0311 g/cm³), close bonding between PET-PVA occurs. Therefore, aerogel shows hydrophobic nature, good mechanical strength, high thermal stability, arrangement of the interconnected fibrillar pore network offers a high surface to volume ratio, low surface energy, high surface roughness, and more reusability. All these parameters are responsible for high oil absorption.

Preparation of aerogel and its application progress in coatings: a mini overview

Aerogels are predominantly mesoporous, extremely lightweight, low density (∼ 0.003 g/cm3) and thermally insulating materials. Over the years, aerogels have gained increasing attention due to their extraordinary properties (light, heat, sound, electricity and force) and application potentials in varieties of fields. Several studies have been carried out regarding aerogel preparation and its applications in coatings on different substrates. In this review, an overview of aerogels preparation and their application progress in coatings of most common substrates is presented. Attention is paid to aerogel coatings of textiles, leather, and substrates other than leather and textiles for special functionalities that could address the application progress in coatings. This review will help to inspire scientists and engineers towards novel aerogel materials and technologies to boost the industrial fabrication of flexible advanced materials.

Sodium silicate-derived aerogels: effect of processing parameters on their applications

Inorganic silica aerogels derived from sodium silicate are voluminous three-dimensional open networks with exceptional properties such as a density as low as ∼100 kg m-3, high porosity (∼99%), low thermal conductivity (∼0.01 W m-1 K-1), high specific surface area (∼1000 m2 g-1), low refractive index (∼1.05) and high optical transmittance (∼95%) depending on their preparation conditions. They are processed through the sol-gel route, which is a reliable methodology to produce high-grade porous materials. Ambient pressure drying has been developed as a low-cost route for the preparation of sodium silicate-derived aerogels, overcoming the difficulties with the use of organosilane precursors and super critical drying. Silica aerogels can be hydrophobic or hydrophilic depending on their synthetic procedure and surface silanol groups. Owing to their unusual properties, these inorganic aerogels have been applied in both commercial and high-tech engineering applications such as thermal insulation, separation, coatings, optics, nuclear particle detection, sensing, and catalysis. This review provides information on the unique features of a wide array of silica aerogels and their potential applications and recent developments in the field of science and technology.

Highly compressible and anisotropic lamellar ceramic sponges with superior thermal insulation and acoustic absorption performances

Advanced ceramic sponge materials with temperature-invariant high compressibility are urgently needed as thermal insulators, energy absorbers, catalyst carriers, and high temperature air filters. However, the application of ceramic sponge materials is severely limited due to their complex preparation process. Here, we present a facile method for large-scale fabrication of highly compressible, temperature resistant SiO₂-Al₂O₃ composite ceramic sponges by blow spinning and subsequent calcination. We successfully produce anisotropic lamellar ceramic sponges with numerous stacked microfiber layers and density as low as 10 mg cm^-3. The anisotropic lamellar ceramic sponges exhibit high compression fatigue resistance, strain-independent zero Poisson's ratio, robust fire resistance, temperature-invariant compression resilience from -196 to 1000 °C, and excellent thermal insulation with a thermal conductivity as low as 0.034 W m^-1 K^-1. In addition, the lamellar structure also endows the ceramic sponges with excellent sound absorption properties, representing a promising alternative to existing thermal insulation and acoustic absorption materials.

Fabrication and in vivo chondrification of a poly(propylene carbonate)/l-lactide-grafted tetracalcium phosphate electrospun scaffold for cartilage tissue engineering

Fabrication and in vivo chondrification of poly(propylene carbonate)/l-lactide-grafted tetracalcium phosphate electrospun scaffold for cartilage tissue engineering.

Preparation of superhydrophobic films based on the diblock copolymer P(TFEMA-r-Sty)-b-PCEMA

The diblock copolymer P(TFEMA-r-Sty)-b-PCEMA was synthesized and self-assembled to form spherical micelles. Photo-cross-linking the PCEMA domains of these micelles yielded cross-linked nanoparticles. The cross-linked nanoparticles were used to prepare superhydrophobic films.