Thermal Insulation and Flame Retardancy of the Hydroxyapatite Nanorods/Sodium Alginate Composite Aerogel with a Double-Crosslinked Structure

Abstract

As advanced thermal management materials, aerogels have great research value in the fields of engineering insulation, pipeline transportation, and packaging insulation. The composite interaction of the two-phase interface and the construction of a porous structure have an important impact on the thermal properties. Herein, a novel HANRs/SAB composite aerogel was prepared using sodium alginate (SA) with hydroxyapatite nanorods (HANRs), combined with boric acid crosslinking and freeze drying. In the prepared sample, the calcium ions in HANRs and SA formed the first layer of binding force and the chemical crosslinking of sodium alginate with boric acid formed the second layer of strong binding force, which effectively supported the skeleton of the aerogel and enhanced the overall mechanical properties. The modulus and maximum compressive strength of the obtained HANRs/SAB aerogel were 2.39 and 0.75 MPa, respectively, while the bulk density was 0.038–0.068 g·cm–3. Based on the prominent physical structure, the as-prepared HANRs/SAB aerogel exhibited good thermal insulation (∼35.15 mW·m–1·K–1) and outstanding flame retardant performance. Flame-retardant boric acid and high-thermal stability HANRs could effectively prevent heat transfer and organic combustion, thus resulting in an extremely low smoke gas release (11.3 m2 m–2). Therefore, the low-cost biopolymer composite aerogel based on a crosslinking strategy has broad application prospects in the field of thermal insulation and flame retardancy.

Biomimetic, Mechanically Strong Supramolecular Nanosystem Enabling Solvent Resistance, Reliable Fire Protection and Ultralong Fire Warning

“…34 It should be noted that, compared with that of the GO paper, the peak intensity of the oxygencontaining group, i.e., C�O was decreased observably, which can well-demonstrate the fact that the boric acid unit effectively forms covalent bonds with the hydroxyl groups on the GO sheets. 41 The formation of multiple interactions in cross-linked network generally can produce a mechanical/ structural reinforcement effect. 42 The comparison of ultrasonic treatment result of the GO paper and GO/MB paper can further verify this effect (Figure 2i).…”

Environment friendly biomass composite aerogel with reinforced mechanical properties for thermal insulation and flame retardancy application

“…By introducing hydroxyapatite nanoparticles into the aerogel, the researchers successfully improved the flame retardant properties of the aerogel and reduced its combustion rate and heat release rate (HRR). It is of great significance to improve the safety and reliability of aerogel 38,39 . Therefore, the mechanical properties, thermal stability and flame retardant properties of aerogel can be improved by introducing hydroxyapatite nanoparticles.…”

“…It is of great significance to improve the safety and reliability of aerogel. 38,39 Therefore, the mechanical properties, thermal stability and flame retardant properties of aerogel can be improved by introducing hydroxyapatite nanoparticles. However, further research is still needed to gain a deeper understanding of the interaction mechanism between hydroxyapatite and aerogel, as well as further research to explore the interaction mechanism between inorganic materials and biomass aerogel, and to find more environmentally friendly and sustainable crosslinkers to achieve better aerogel performance.…”

Aptamer-modified Zr-MOFs to construct nanocatalysts with engineered specificity toward paraoxon

“…18 Besides, the amino stretching vibration peaks at 3393 and 3508 cm À1 in BDC-NH 2 disappeared in UiO-66-NH 2 and UiO-66-5 0 C6, owing to the formation of intra-skeletal hydrogen bonds between the amino group and the electron donor oxygen in the carboxyl group. 19 Compared with UiO-66-NH 2 , the C-N stretching vibration peak at 1256 cm À1 is obviously enhanced in UiO-66-5 0 C6, and the weak bands at 1161, 1016 and 964 cm À1 correspond to the P-O stretching vibration, 20 which thus implied the linking of the aptamer. This result was also supported by XPS analysis that an additional P 2p signal 21 (Fig.…”