Surface sedimentation and adherence of Nano‐SiO₂ to improve thermal stability and flame resistance of melamine‐formaldehyde foam via sol‐gel method

Abstract

Summary Melamine‐formaldehyde foam possesses intrinsic flame retardance; however, relative poor thermal stability and a certain amount of heat release rate restrict its applications in heated environment to a degree. In the present research, sol‐gel method has been adopted to precipitate nano‐SiO2 particles on the surface of the melamine‐formaldehyde foam's fibers to construct a protective inorganic gel layer. Taking advantages of the shielding effects of the gel layer, the thermal‐oxygen degradation of the foam can be greatly retarded during heating; hence, the thermal stability is remarkably improved, and the flame retardance is further enhanced. In addition, introducing a small amount of membrane‐forming agent in the sol‐gel system can make the depositional nano‐SiO2 particles well adhered to avoid dusting.

Green Preparation of Straw Fiber Reinforced Hydrolyzed Soy Protein Isolate/Urea/Formaldehyde Composites for Biocomposite Flower Pots Application

“…However, with increasing concern about environmental pollutants produced from the formaldehyde of the U/F resin, researchers have focused on environmentally friendly polymers for reducing the amount of formaldehyde. Lots of effort has been taken to reduce formadehyde emissions by adding compounds into U/F, including core flour [ 23 , 24 ], glycolysis products [ 25 ], scallop shell nanoparticles [ 26 ], nano SiO 2 [ 27 , 28 , 29 ], nanocrystalline cellulose [ 30 ], and corn flour [ 31 ].…”

Non‐Volatile Glycerin Gel Enhanced by Sub‐5 nm Particles with Super Elasticity, Recoverability, and High Temperature Resistance

“…Since the glycerin and polymer were well mixed and very stable, the PAM/CNS/GC NV gel sample, which was used in the compression test (first compression test, which is shown in Figure c,d), was once again applied to the process of drying (90 °C, in vacuum, 24 h) and second compression test ( Figure ) . With the enhancement of sub‐5 nm CNS and non‐volatile glycerin, the NV gel still had a similar appearance to its initial state even after applying a series of extreme conditions (the first compression test, drying under vacuum, and second compression test) (Figure a).…”

“…Hydrogels from polymeric networks are promising elastic materials that contain a large amount of deionized water and play a central role in a number of wearable and implantable devices, absorbents, biosensors, regenerative medicine, tissue repair, and super absorbents . However, the potential application of hydrogels has been greatly limited by the evaporation when they are used in an open environment . Although the cross‐linked network of the polymer is carefully designed, the water will still boil at about 100 °C and freeze around 0 °C.…”

In‐situ synthesis and adhesion method to prepare phosphorous–nitrogen compounds flame‐retardant wood pulp paper with high efficiency and durability

“…Additionally, sol–gel technique and layer‐by‐layer (LBL) assembly technologies have been employed to prepare flame‐retardant cellulosic materials with improved water resistance recently 27‐29 . Jiang prepared a flame‐retardant cotton fabric through sol–gel method.…”