Biodegradable cellulose-base aerogel films with high solar emissivity for agricultural thermal management

Petroleum-based agricultural films, which is widely utilized, exacerbates the oil resource shortage and environmental pollution by leaving large amounts of residue in the soil. Agricultural films made of petroleum need to be replaced with biodegradable agricultural films that have the potential to increase temperature, maintain moisture, and be biodegradable in order to tackle this issue. Here, regenerated cellulose and boron nitrogen nanosheets (BNNS) were combined and processed by dissolution, regeneration, and freeze-drying to fabricated regenerated cellulose/BNNS aerogel films (RCB aerogel films). Regenerated cellulose as main skeleton of the aerogel films, while BNNS acted as filling materials to modulate the film’s thermal conductivity (4.023 W·m⁻¹·K⁻¹) for transferring heat both internally and externally. Meanwhile, the regenerated cellulose endows the RCB aerogel films, shows high solar emissivity up to 0.96, and emits strongly in the atmospheric transparency window thereby achieving radiating cooling of 6 ℃ on a hot day for mulch films. Additionally, rice straw cellulose is dissolved in regenerated cellulose sheets from the regeneration process, accelerating the degradation of RCB aerogel films. The results of biodegradation tests show that the RCB aerogel films have been completely degraded within 25 days. RCB aerogel films also have excellent mechanical properties, folding, and moisture management properties. In summary, the fabricated RCB aerogel films in this work had potential application in agricultural mulch films due to their thermal management properties, mechanical properties, degradation properties, and the development and application of biodegradable mulch can greatly reduce the increasing environmental pollution pressure.