Ultralight Industrial Bamboo Residue-Derived Holocellulose Thermal Insulation Aerogels with Hydrophobic and Fire Resistant Properties

Abstract

In this study, water-soluble ammonium polyphosphate- (APP) and methyl trimethoxysilane (MTMS)-modified industrial bamboo residue (IBR)-derived holocellulose nanofibrils (HCNF/APP/MTMS) were used as the raw materials to prepare aerogels in a freeze-drying process. Synthetically modified aerogels were confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, and thermal stability measurements. As-prepared HCNF/APP/MTMS aerogels showed themselves to be soft and flexible. The scanning electron microscopy (SEM) analysis showed that the foam-like structure translates into a 3D network structure from HCNF aerogels to HCNF/APP/MTMS aerogels. The compressive modules of the HCNF/APP/MTMS aerogels were decreased from 38 kPa to 8.9 kPa with a density in the range of 12.04–28.54 kg/m3, which was due to the structural change caused by the addition of APP and MTMS. Compared with HCNF aerogels, HCNF/APP/MTMS aerogels showed a high hydrophobicity, in which the water contact angle was 130°, and great flame retardant properties. The peak of heat release rate (pHRR) and total smoke production (TSP) decreased from 466.6 to 219.1 kW/m2 and 0.18 to 0.04 m2, respectively, meanwhile, the fire growth rate (FIGRA) decreased to 8.76 kW/s·m2. The thermal conductivity of the HCNF/APP/MTMS aerogels was 0.039 W/m·K. All results indicated the prepared aerogels should be expected to show great potential for thermally insulative materials.

Fiber-Based Noncontact Sensor with Stretchability for Underwater Wearable Sensing and VR Applications

“…The hydrophobicity is attributed to the hydrophobic layer of polysiloxane formed on the surface of BBT helical fiber after silanization treatment, which reduces the surface energy of the helical fiber and forms a hydrophobic surface, allowing the water droplet to stably exist on the uneven surface of the SBBT helical fiber without being absorbed (Figure b). , As shown in Figure c, the characteristic peaks appeared as broad absorption peaks at 3430 cm –1 , indicating the stretching vibrations of – OH. The stretching vibrations of C–H at 2926 cm –1 , H–O–H at 1634 cm –1 , and C–OH at 1128 cm –1 are all presented in the fibers before and after silylated modifcation. − , After silylated modification, the characteristic vibrational peaks of the distinct Si–C peak at 1273 cm –1 , Si–O–C and Si–O–Si peaks at 1027 cm –1 , and Si–C and Si–O–Si stretching vibrations at 783 cm –1 indicate the formation of polysiloxane networks. − , In addition, a 29 SiNMR spectrum of helical fiber was obtained, indicating the occurrence of a silylation reaction, with polysiloxane formed through self-polymerization and condensation with hydroxyl groups on the surface of BC. ,,, It shows two characteristic peaks at −57 and −66 ppm, corresponding to T 2 (linear link) and T 3 (three-dimensional), indicating the synthesis of the polysiloxane network system with two- and three-dimensional structures (Figure d). ,,, Meanwhile, the appearance of the diffraction peak at 10.6° on the XRD spectrum further indicates the successful polymerization of polysiloxane (Figure S7), while other similar peak positions confirm that the internal structure of the structural domain in SBBT fibers remains unchanged after the silylation reaction. ,, Therefore, the polysiloxane network is synthesized and stably attached to the surface of the BC layer through a covalent chemical bond and hydrogen bond connection, which is fundamentally different from the physical coatings reported in the previous literature. ,,, …”

Analisis Holoselulosa: Tinjauan Metode Analisis Kimia Konvensional

“…Holoselulosa menjadi bahan yang mendapatkan perhatian karena merupakan bahan baku yang digunakan untuk menghasilkan pulp dan kertas (Ramawat and Ahuja, 2016), holoselulosa nanofibril (Park et al, 2017), selulosa alfa (Sunardia et al, 2019), biokomposit (Yang et al, 2019), bioetanol (Vaz et al, 2016), aerogel (Huang et al, 2020).…”

Cellulose Nanocrystals/Melamine/Phytic Acid Nanocomposites as Thermally Insulating and Flame-Retardant Structural Materials

“…This three-dimensional porous carbon residue can form an effective dense- and gas-phase barrier with low conductivity to improve the properties of heat insulation and flame retardancy. This unique two-phase barrier structure is supposed to be superior to FR aerogels with a dense phase only, especially performed in higher total smoke production, as listed in Table S5. − …”