An Alginate Hybrid Sponge with High Thermal Stability: Its Flame Retardant Properties and Mechanism

Abstract

The worldwide applications of polyurethane (PU) and polystyrene (PS) sponge materials have been causing massive non-renewable resource consumption and huge loss of property and life due to its high flammability. Finding a biodegradable and regenerative sponge material with desirable thermal and flame retardant properties remains challenging to date. In this study, bio-based, renewable calcium alginate hybrid sponge materials (CAS) with high thermal stability and flame retardancy were fabricated through a simple, eco-friendly, in situ, chemical-foaming process at room temperature, followed by a facile and economical post-cross-linking method to obtain the organic-inorganic (CaCO 3 ) hybrid materials. The microstructure of CAS showed desirable porous networks with a porosity rate of 70.3%, indicating that a great amount of raw materials can be saved to achieve remarkable cost control. The sponge materials reached a limiting oxygen index (LOI) of 39, which was greatly improved compared with common sponge. Moreover, with only 5% calcium carbonate content, the initial thermal degradation temperature of CAS was increased by 70 • C (from 150 to 220 • C), compared to that of calcium alginate, which met the requirements of high-temperature resistant and nonflammable materials. The thermal degradation mechanism of CAS was supposed based on the experimental data. The combined results suggest promising prospects for the application of CAS in a range of fields and the sponge materials provide an alternative for the commonly used PU and PS sponge materials.

Studying structural and rheological properties of alginate‐whey protein isolate cold‐set hybrid emulgels at various pH levels

“…Figure 8 shows the results of temperature sweep test of emulgels. In the studied range, the values of G ′ were always larger than those of G ″, which implies the heat stability of CA‐based emulgels (Jiang et al, 2019). Both emulgels did not reveal any dependency of viscoelastic moduli to temperatures <100°C, especially at pH values of 4 and 5.…”

Electrically Conductive Natural Rubber Composite Films Reinforced with Graphite Platelets

“…It has captured researchers’ attention due to its easy availability, non-toxic nature, biocompatibility, gel-forming property, and ability to degrade naturally [ 21 , 22 ]. When incorporated into NR, it offers a range of benefits, such as improving biodegradability, water-retention properties, processability, and both chemical and thermal stability [ 22 , 23 , 24 ]. Moreover, it acts as an efficient dispersing and thickening agent, increasing the viscosity of the rubber matrix.…”

Exploring the Impact of Alginate—PVA Ratio and the Addition of Bioactive Substances on the Performance of Hybrid Hydrogel Membranes as Potential Wound Dressings

“…Alginate extract is found as a sodium or calcium salt and contains numerous hydroxyl and carboxyl functional groups, enabling the formation of intramolecular hydrogen bonds [ 14 , 16 , 17 , 18 , 19 ]. Depending on the processing method, it can be produced as foams [ 20 , 21 ], sponges [ 22 , 23 ], hydrogels [ 24 , 25 , 26 ], films [ 27 , 28 , 29 ], nanofibers [ 30 , 31 , 32 ], or nanoparticles [ 33 , 34 , 35 ]. Alginate can be crosslinked via physical or chemical methods [ 14 ].…”