Ye Niu,JiaoJiao Zhao,Chi Liu,Yi Zhang,JiaJia Pang,Shuo Wang
With the increasing awareness of environmental protection, polysaccharide packaging materials have received widespread attention. In this work, a kind of novel polysaccharide composite membrane was prepared by hollow glass microspheres (HGM) into agar (AG) and sodium alginate (SA) matrix and then cross-linking by glycerol (abbreviated as AG-SA-HGM). The addition of hollow glass microspheres significantly improved the thermal stability and flame retardancy of the polysaccharide membrane, with a peak heat release rate of only 72.05 kW m −2 . Besides, the prepared flame retardant packaging membrane not only has excellent flexibility, no cracks after folding, and can restore its original state, but also exhibits special properties of front hydrophobicity (contact angle of 123.82°) and back hydrophilicity (contact angle of 35.33°). Therefore, AG-SA-HGM composite membrane has great potential in flame retardant applications.
Zhengkai You,Xiaolong Li,Jing Huang,Rongqin Chen,Jiyu Peng,Wenwen Kong,Fei Liu
Laser-induced breakdown spectroscopy (LIBS) shows promising applications in the analysis of environmental heavy metals. However, direct analysis in water by LIBS faces the problems of droplet splashing and laser energy decay. In this study, a novel liquid–solid conversion method based on agarose films is proposed to provide an easy-to-operate and sensitive detection of heavy metals. First, the water samples were converted into semi-solid hydrogels with the aid of agarose and then dried into agarose films to make the signal intensities stronger. The calibration curves of Cd, Pb and Cr were constructed. The proposed method was validated by standard heavy metal solutions and real water samples. The results showed that the values of R2were 0.990, 0.989 and 0.975, and the values of the LOD were 0.011, 0.122 and 0.118 mg L−1for Cd (I) 228.80, Pb (I) 405.78 and Cr (I) 427.48 nm, respectively. The RMSEs of validation were 0.068 (Cd), 0.107 (Pb) and 0.112 mg·L−1(Cr), and the recovery values were in the range of 91.2–107.9%. The agarose film-based liquid–solid conversion method achieved the desired ease of operation and sensitivity of LIBS in heavy-metal detection, thereby, showing good application prospects in heavy metal monitoring of water.Keywords:heavy metal detection;laser-induced breakdown spectroscopy;liquid–solid conversion;agarose film
Hull-less barley grass polysaccharide extracts (HBP) are prepared, and the physicochemical and antioxidant properties of agar films with different HBP contents (0, 0.5, 1, 1.5, and 2% w/w of agar mass) are investigated. Infrared spectroscopy shows that HBP interacts with the agar matrix via intermolecular hydrogen bonds. The incorporation of HBP causes rougher surface morphology with increased film thickness ( p < 0.05). The films with HBP exhibit decreased brightness with a greenish and yellowish hue. The flexibility of the films is improved gradually as HBP contents increase from 0 to 1.5% w/w ( p < 0.05), however, a slight reduction is observed with 2% w/w HBP addition ( p > 0.05). The water resistance and surface hydrophobicity of the films are enhanced by adding HBP ( p < 0.05). The antioxidant test reveals the strong antioxidant capacity of the HBP-loaded films, which is positively correlated with the HBP contents ( p < 0.05), with 2% w/w HBP leading to 59.28% DPPH radical scavenging and 69.00% ABTS radical scavenging. Results suggest that HBP is a promising functional agent for developing antioxidant biopolymer films, and the agar/HBP edible films prepared in this study have potential in food packaging fields.
危险品化学品经营许可证（带存储）