Autonomous Underwater Self-Healable Adhesive Elastomers Enabled by Dynamical Hydrophobic Phase-Separated Microdomains.

High-efficient underwater self-healing materials with reliable mechanical attributes hold great promise for applications in ocean explorations and diverse underwater operations. Nevertheless, achieving these functions in aquatic environments is challenging because the recombination of dynamic interactions will suffer from resistance to interfacial water molecules. Herein, an ultra-robust and all-environment stable self-healable polyurethane-amide supramolecular elastomer is developed through rational engineering of hydrophobic domains and multistrength hydrogen bonding interactions to provide mechanical and healing compatibility as well as efficient suppression of water ingress. The coupling of hydrophobic chains and hierarchical hydrogen bonds within a multiphase matrix self-assemble to generate dynamical hydrophobic hard-phase microdomains, which synergistically realize high stretchability (1601%), extreme toughness (87.1 MJ m-3), and outstanding capability to autonomous self-healing in various harsh aqueous conditions with an efficiency of 58% and healed strength of 12.7 MPa underwater. Furthermore, the self-aggregation of hydrophobic clusters with sufficient dynamic interactions endows the resultant elastomer with effective instantaneous adhesion (6.2 MPa, 941.9 N m-1) in extremely harsh aqueous conditions. It is revealed that the dynamical hydrophobic hard-phase microdomain composed of hydrophobic barriers and cooperative reversible interactions allows for regulating its mechanical enhancement and underwater self-healing efficiency, enabling the elastomers as intelligent sealing devices in marine applications.

Facile and green preparation of solid carbon nanoonions via catalytic co-pyrolysis of lignin and polyethylene and their adsorption capability towards Cu(ii).

Carbon nanomaterials, such as carbon nanoonions (CNOs), possess promising applications in various fields. There are urgent demands to synthesize carbon nanomaterials from a green and renewable carbon source. In this study, solid CNOs with relatively uniform size distribution (with diameters of about 30-50 nm), abundant structure defects and oxygen-containing surface functional groups (such as -OH and -COOH) are developed from co-pyrolysis of lignin (LG) and polyethylene (PE) in the presence of Ni-based catalysts. The type of catalyst, the concentration of catalyst and catalytic co-pyrolysis temperature play important roles in the morphologies and properties of CNOs as confirmed by TEM and SEM. Furthermore, the produced CNOs can act as a low-cost and highly-efficient adsorbent to remove Cu(ii) from aqueous solution according to a homogeneous monolayer, chemical action-dominated, endothermic and spontaneous process. The theoretical maximum adsorption capacity of CNOs calculated from the Langmuir model is 100.00 mg g-1. Surface deposition, complexation, π electron-cation interaction and electrostatic interaction are responsible for the adsorption of Cu(ii) using the prepared CNOs.

Spatiotemporal variations and risk assessment of ambient air O3, PM10 and PM2.5 in a coastal city of China.

Rapid industrialization and urbanization has created significant air pollution problems that have recently begin to impact the lives and health of human beings in China. This study systematically investigated the spatiotemporal variations and the associated health risks of ambient O3, PM10 and PM2.5 between 2016 and 2019. The relationships between the target air pollutants and meteorological conditions were further analyzed using the Spearman rank correlation coefficient method. The results demonstrated that the annual mean concentrations of PM10 and PM2.5 experienced a decreasing trend overall, and PM2.5 significantly decreased from 1.54 µg/m3 in 2016 to 1.48 µg/m3 in 2019. In contrast, the annual mean concentrations of O3 were nearly constant during the study period with a slight increasing trend. The pollutants exhibited different seasonal variations and cyclical diurnal variations. The most highest O3 pollution was seen in spring and summer, while spring and winter were the seasons with the most PM10 and PM2.5 pollution. The highest concentrations of O3 appeared in periods of strong solar radiation intensity and photochemical reactions. The highest concentrations of PM10 and PM2.5 appeared at commuting time. The pollutant concentrations were significantly affected by meteorological conditions. Finally, the non-carcinogenic risks from exposure to O3, PM10 and PM2.5 were at an acceptable level (HI < 0.96) and O3 accounted for ~50% of the total non-carcinogenic risks. However, PM2.5 posed highly carcinogenic risks (2.5 × 10-4 < CR < 1.6 × 10-1) and O3 exposure showed high potential ecological impacts on vegetation (AOT40: 23.3 ppm-h; W126: 29.0 ppm-h).

Salt Effect on the Isobaric Vapor-Liquid Equilibrium Study of Binary Mixtures H2O-NMP (N-Methyl-2-pyrrolidone).

To study the salt effect of recovering N-methyl-2-pyrrolidone (NMP) from the waste liquid produced in the polyphenylene sulfide (PPS) synthesis process, this study presents vapor-liquid equilibrium (VLE) measurement and correlation for water + NMP, water + NMP + lithium chloride, and water + NMP + sodium chloride at p = 101.3 kPa. The salt effect is discussed and the salts follow the order of lithium chloride > sodium chloride. The NRTL model was used for the correlation with binary parameters of water + NMP, water + NMP + lithium chloride, and water + NMP + sodium chloride. The correlation showed good agreement with experimental data; root-mean-square deviations are less than 0.48 K for the equilibrium temperature and 0.005 for the vapor-phase mole fraction of water.