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The research progress, existing problems and future development of flame retarding modification of bio-based polyurethane are summarized. The work summarized the research status of commonly used methods for preparing bio-based polyurethane, including basic characteristics, application effect and development prospect of various flame retardant agent. At present, vegetable oil-based polyols can effectively replace traditional industrial synthetic petroleum-based polyols as raw materials for the synthesis of bio-based polyurethane. However, there are still some shortcomings in this area that have not been addressed. The defects of polyurethane, such as flammability and smokiness, need to be improved. The practical application conversion rate of research results was not high. The environmental protection and safety performance of bio-based polyurethane can be further improved and enriched. Therefore, more efforts should be put into the above questions, which were all of great significance to the development of polyurethane. The research on retarding modification of polyurethane will have great development space and application value in the future. [ABSTRACT FROM AUTHOR]

Wood–plastic composites (WPCs) are facing fire hazard when they are used in construction and furniture and need to be treated with fire protection. In this work, polyurethane (PU) was applied to derive simultaneously flame‐retardancy‐improved and mechanically strengthened wood‐polyurethane composites (WPUCs). It was constructed with ammonium polyphosphate (APP) and PU by a simple way. The results showed that a decrease in smoke production in the Cone Calorimeter Test was measured. When the mass of APP is 18% of PU, limiting oxygen index can reach 31.2%. In the combustion test, the peak of heat release rate and total smoke production for WPUCs were, respectively, decreased by 42.1% and 89.7% in the presence of the above ratio of APP and PU. In addition, the results of the functional group test show that PU contains highly reactive ‐NCO which is bonded to the ‐OH and moisture in the wood fiber, resulting in improvement of physical and mechanical properties. The mechanism for the flame retardancy of WPUCs revealed that polyphosphoric acid produced by APP pyrolysis catalyzed PU into the char, and PU was arched by the resulting gases such as NH3 to form the tiny spherical structure, which worked in blocking heat and the exchange of substances. WPUCs with APP prepared by this method are shown to have improved results, and, therefore, it is expected to provide a new strategy for the preparation of flame‐retardant WPCs. [ABSTRACT FROM AUTHOR]

Egineering running experience shows that with the increase of the operating voltage of the transmission line, the lightning trip rate is increasing. According to theoretical calculation ， UHV transmission lines should be provided with full lightning protection characteristics；however，running experience shows that the lightning withstand level of UHV transmission lines is high，not completely lightning protection; it puts forward higher requirements for lightning protection design of UHV transmission line in China. UHV transmission line is mainly against direct lightning stroke characteristics， one is caused by lightning counterattack trip，the other is the shielding failure of lightning around the line to strike the wound caused by the wire. The lightning fault type identification is based on the micro topography of UHV transmission tower，accumulation of historical data，the development of a more targeted and high voltage transmission line lightning protection scheme is of great significance. In this paper, a real-time identification system based on UV detection technology, which has high accuracy and fast response time, is proposed for lightning fault types of UHV transmission lines, the systems use ultraviolet light to realize online detection of high-voltage transmission line tower nearby lightning, can effective observation tower near lightning discharge, and it has the characteristics of continuous detection, longdistance, no power supply, no contact and no disassembly, it provides an advanced technology for the detection of lightning discharge in UHV transmission line.

BACKGROUND: With the improvements in bioethanol production, the process of converting ethanol to 1,3‐butadiene (ETB) has received substantial scholarly attention, whose industrialization has been constrained by the stability of the catalysts. RESULTS: In this work, the deactivation behavior of Zr‐β zeolite in the process of ethanol/acetaldehyde conversion to 1,3‐butadiene was investigated. In addition, the deactivation kinetics of ETB was studied using an isothermal differential microreactor. A kinetic model was developed and parametrized with the Langmuir–Hinshelwood mechanism, and the intrinsic kinetic equation was derived. The deactivation kinetic model of the ETB reaction was established from the active site content of the catalyst as a function of time on stream. The validity of the kinetic model was tested, and the results were found to be accurate. CONCLUSIONS: Catalyst deactivation was mainly caused by coke species, which are mainly long‐chain unsaturated oxygenated organic compounds and aromatic compounds, covering Lewis acid sites in the microporous channels of the catalyst; nevertheless the zeotype topology and morphology were not destroyed. The kinetic data suggested that the reaction was of first order and the activation energy of the deactivation process was 75.59 kJ mol−1. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]