Effects of composition on the properties of dual physically cross-linked hydrogel composed of polyvinyl alcohol and poly (acrylamide-co-acrylic acid)

Facile Fabrication of Multifunctional Transparent Flame-Retarded Hydrogel for Fire-Resistant Glass with Excellent Transparency, Fire Resistance and Anti-Ageing Property

Acrylamide-methacrylic acid copolymer named P (AM-co-MAA) was synthesized via aqueous solution polymerization, and then mixed with crosslinker, flame retardants and initiators to prepare multifunctional transparent flame-retarded hydrogels with transparency, fire resistance and anti-ageing property. The results show that the application of multifunctional transparent flame-retarded hydrogel imparts high level of transparency and excellent fire resistance to the fire-resistant glass, and the light transmittance and fire resistance of the flame-retarded hydrogel increases with the increasing mass ratio of AM to MAA in P(AM-co-MAA). When the mass ratio of AM to MAA is 4:1, the obtained P(AM-co-MAA) imparts the lowest backside temperature of 130 °C at 3600 s and highest light transmittance of 86.1% to the transparent flame-retarded hydrogel. TG and DSC analysis show that the addition of P(AM-co-MAA) increases the thermal stability of the transparent flame-retarded hydrogels due to the formation of numerous hydrogen bonds via the complexation between amide and carboxyl groups. Accelerated ageing test indicates that the transparent flame-retarded hydrogel containing P(AM-co-MAA) exerts durable fire resistance and transparency, and the ageing resistance of the transparent flame-retarded hydrogel depends on the mass ratio of AM to MAA in P(AM-co-MAA). Therefore, this study provides a promising strategy to prepare a novel multifunctional transparent flame-retarded hydrogel with excellent light transmittance, fire resistance and anti-ageing properties.

Effect of Poly(acrylamide-acrylic acid) on the Fire Resistance and Anti-Aging Properties of Transparent Flame-Retardant Hydrogel Applied in Fireproof Glass

Poly(acrylamide-acrylic acid) (P(AM-co-AA)) was synthesized via the copolymerization of acrylamide and acrylic acid and well characterized by Fourier transform infrared spectroscopy. Afterward, the obtained P(AM-co-AA) was blended with flame retardants to prepare transparent flame-retardant hydrogel applied in the fireproof glass. The influence of poly(acrylamide-acrylic acid) on fire resistance and anti-aging properties of the transparent flame-retardant hydrogels were studied by assorted analysis methods. The optical transparency analysis shows that the light transmittance of the transparent flame-retardant hydrogel gradually decreases with the decreasing mass ratio of acrylamide to acrylic acid in P(AM-co-AA). Heat insulation testing shows that the heat insulation performance of fireproof glass applying the transparent flame-retardant hydrogel firstly decreases and then increases with decreasing mass ratio of acrylamide to acrylic acid in P(AM-co-AA). When the mass ratio of acrylamide to acrylic acid is 1:2, the obtained P(AM-co-AA) endows the resulting flame-retardant hydrogel applied in fireproof glass with the lowest light transmittance of 81.3% and lowest backside temperature of 131.4 °C at 60 min among the samples, which is attributed to the formation of a more dense and expanded char to prevent the heat transfer during combustion, as supported by the digital photos of char residues. The results of TG analysis indicate that P(AM-co-AA) imparts high thermal stability to the resulting hydrogels due to the hydrogen bonds between carboxyl and amide groups. The accelerated aging test shows that the transparent flame-retardant hydrogel containing P(AM-co-AA) is less affected by aging conditions. Especially, when the mass ratio of acrylamide to acrylic acid in P(AM-co-AA) is 4:1, the resulting transparent flame-retardant hydrogel shows a light transmittance of 82.9% and backside temperature of 173.1 °C at 60 min after 7 aging cycles, exhibiting the best comprehensive properties among the samples.

A Review of the Use of GPEs in Zinc-Based Batteries. A Step Closer to Wearable Electronic Gadgets and Smart Textiles

With the flourish of flexible and wearable electronics gadgets, the need for flexible power sources has become essential. The growth of this increasingly diverse range of devices boosted the necessity to develop materials for such flexible power sources such as secondary batteries, fuel cells, supercapacitors, sensors, dye-sensitized solar cells, etc. In that context, comprehensives studies on flexible conversion and energy storage devices have been released for other technologies such Li-ion standing out the importance of the research done lately in GPEs (gel polymer electrolytes) for energy conversion and storage. However, flexible zinc batteries have not received the attention they deserve within the flexible batteries field, which are destined to be one of the high rank players in the wearable devices future market. This review presents an extensive overview of the most notable or prominent gel polymeric materials, including biobased polymers, and zinc chemistries as well as its practical or functional implementation in flexible wearable devices. The ultimate aim is to highlight zinc-based batteries as power sources to fill a segment of the world flexible batteries future market.