Polyvinyl alcohol composite aerogel with remarkable flame retardancy, chemical durability and self-cleaning property. (October 2019) - Zhang, Qiaoran
Abstract: Polyvinyl alcohol (PVA) aerogel has aroused great interest in various fields, due to its low-cost, good environmental acceptance and ultra-low density. However, the application of PVA aerogel is limited by its inflammability and superhydrophilicity. Therefore, boron nitride (BNNS) and ammonium polyphosphate (APP) were used as flame retardants and incorporated into PVA aerogel so as to improve the fire resistance. The flame-retardant performance of the PVA-matrix composite aerogels was evaluated by cone calorimetry test; and their decomposed products were analyzed by thermogavimetry-infrared spectrometry. Further, the surface of the as-prepared PVA-matrix aerogel was modified by polydimethylsiloxane (PDMS) and hydrophobic SiO2 so as to construct micro/nanoscale rough structures with desired chemical durability and self-cleaning ability. Results show that the as-prepared PVA-matrix composite aerogels exhibit an obviously decreased peak heat release rate and total heat release than the pristine PVA aerogel; and the incorporation of BNNS and APP contributes to significantly suppressing the release of flammable gases such as hydrocarbon and aromatic compounds. More important, after the encapsulation of PVA-matrix composite aerogel with PDMS and hydrophobic SiO2, the resultant micro/nanoscale rough surface structure exhibits superhydrophobicity as well as excellent pH-tolerance, ultraviolet irradiation resistance, self-cleaning ability, and fire resistance. Graphical abstract: Image 1 Highlights: A multifunctional PVA-matrix composite aerogel was successfully prepared. The PVA-matrix composite aerogel exhibits excellent flame-retardant performance. It shows superhydrophobicity, pH-tolerance and self-cleaning ability via modification.