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•A novel water-soluble lignin-based N-P flame retardant was synthesized.•Modified wood showed good mechanical properties and dimensional stability.•Modified wood achieved a reduction ...of 56.8% in THR and 92.3% decrease in TSP.•The flame-retardant mechanism of modified wood has been revealed.
The development of effective and eco-friendly wood-based functional composites is crucial for maximizing the value of forest resources. In this paper, we propose a novel method for preparing an aqueous-phase flame retardant (MPUC) using carboxymethylation alkali lignin, phytic acid, and melamine-urea-glyoxal resin. This approach aims to manufacture modified wood (MW/MPUC) with exceptional flame-retardant and smoke-suppressing properties. The results from the cone calorimeter test indicate that the modified wood achieved a remarkable reduction of up to 56.8 % in total heat release and an impressive 92.3 % decrease in total smoke production. Furthermore, the limiting oxygen index increased significantly from 23.6 % (natural wood) to 41.5 % (MW/MPUC-2). Notably, all modified wood successfully passed the V-1 test for UL-94 flammability rating. Further, our investigation into the gas-phase products formed during pyrolysis and the condensed-phase system created after combustion has led us to propose potential flame-retardant mechanisms for these flame retardants. Moreover, modified wood had improved mechanical properties and dimensional stability than natural wood. In addition, we extended the application of MPUC-2 flame-retardant to other flammable materials and demonstrated its excellent flame-retardant properties. Thus, the proposed strategy provided a new approach for preparing wood-based flame-retardant composites with lignin-based N-P flame retardants.
To intervene the health behavior of lead exposed workers by setting down and implementing a series of measures and evaluating the effects of these measures so that the occupational lead poisoning ...would be decreased.
105 lead exposed workers in a factory were chosen as subjects. Blood lead concentration and rate of cognition on relevant health knowledge were examined before and after intervened measures.
The cognition rate raised from 56.6% to 97.3% after training. Lead concentration in blood decreased by 17.7% (t = 4.10, P = 0.000) and delta-ALA in urine decreased by 23.9% (t = 4.248, P = 0.000) 12 months after intervention. The prevalence of occupational lead absorption and poisoning also decreased. The number of workers with blood lead content > 2.41 mumol/L was decreased from 6 to 3, and > 1.93 mumol/L from 14 to 10.
To develope occupational health promotion, enhance health education and improve health behavior are the effective way to prevent from occupational lead poisoning.
