Silica-Bacterial Cellulose Composite Aerogel Fibers with Excellent Mechanical Properties from Sodium Silicate Precursor

Abstract

Forming fibers for fabric insulation is difficult using aerogels, which have excellent thermal insulation performance but poor mechanical properties. A previous study proposed a novel method that could effectively improve the mechanical properties of aerogels and make them into fibers for use in fabric insulation. In this study, composite aerogel fibers (CAFs) with excellent mechanical properties and thermal insulation performance were prepared using a streamlined method. The wet bacterial cellulose (BC) matrix without freeze-drying directly was immersed in an inorganic precursor (silicate) solution, followed by initiating in situ sol-gel reaction under the action of acidic catalyst after secondary shaping. Finally, after surface modification and ambient drying of the wet composite gel, CAFs were obtained. The CAFs prepared by the simplified method still had favorable mechanical properties (tensile strength of 4.5 MPa) and excellent thermal insulation properties under extreme conditions (220 °C and −60 °C). In particular, compared with previous work, the presented CAFs preparation process is simpler and more environmentally friendly. In addition, the experimental costs were reduced. Furthermore, the obtained CAFs had high specific surface area (671.3 m²/g), excellent hydrophobicity, and low density (≤0.154 g/cm3). This streamlined method was proposed to prepare aerogel fibers with excellent performance to meet the requirements of wearable applications.

Mechanically Strong and Thermally Insulating Polyimide Aerogel Fibers Reinforced by Prefabricated Long Polyimide Fibers

“…Therefore, considering both strength and toughness, LPF-PAF 7.5 was chosen for further study. Compared with other aerogel fibers in the literature, the obtained LPF-PAFs (150 MPa) are stronger than most, indicating this reinforcement method’s rationality (Figure c). ,− ,,,,− As shown by stress–strain curves in Figure d,e, neat PAF displays a low tensile strength of 17 MPa, which is far lower than that of LPF, indicating the significance of LPF for enhancing the strength of LPF-PAF. According to the classical composite reinforcement theory, the strength of composites consisting of a soft matrix and long fibers is controlled by five parameters, namely, the ultimate strength of the matrix ( X m ) and long fibers ( X f ), the ultimate strain of long fibers (ε), the strength of the matrix at an ultimate strain of long fibers ( X ε ), and the volume fraction of long fibers ( C f ).…”

Role of Graphene Oxide in Bacterial Cellulose−Gelatin Hydrogels for Wound Dressing Applications

“…The vibration band between 1000 and 1100 cm –1 may be due to the TEOS crosslinker. The vibration peaks at 1069 and 1020 cm –1 result from the siloxane bond (Si–O−) and ensure the TEOS presence. , The hydrogels (GBG-1, GBG-2, GBG-3, and GBG-4) confirm the presence of all components (BC, gelatin, and GO) and TEOS crosslinks to the polymeric matrix.…”

Bioinspired Thermochromic Textile Based on Robust Cellulose Aerogel Fiber for Self-Adaptive Thermal Management and Dynamic Labels

“…This trend is in agreement with previous reports of other aerogel materials. , Therefore, the nanopore structure of CAFs can be designed by adjusting the quantity of dissolution cellulose and a reasonable TBA replacement-freeze-drying process, which can optimize the mechanical properties of CAFs. Figure c shows the data of breaking strength and elongation for as-prepared pure CAFs and some high-performance aerogel fibers or porous fibers, including graphene aerogel composite fibers, , aramid nanofiber-based aerogel fibers, , polyimide aerogel fiber, , regenerated cellulose aerogel fibers, silk firoin-based aerogel fibers, silica-bacterial cellulose composite aerogel fibers, and silica aerogel fibers . The comparison shows that CAFs have good comprehensive mechanical properties.…”