Jinhua Liu,Lan Guan,Zhe Li,Li Huang,Dan Li,Zhe Li,Xiaohui Wang,Yingqun Zhu,Yuanan Liu
Real-time blood gas analysis is of great significance in disease diagnosis and treatment. Here we have developed a pH, PO 2 and PCO 2 multifunctional fluorescent capillary sensing system. The pH, O 2 and CO 2 fluorescent indicators with same excitation wavelength are fixed into a single capillary tube. The sensing system possesses sensitive fluorescence response to pH, O 2 and CO 2 , and the changes of pH, O 2 and CO 2 in buffer, in vitro, and in vivo can be detected simultaneously by measuring the fluorescence signals of sensor probe. The PO 2 , PCO 2 and pH of rabbits in four disease models were assessed efficiently by the sensing system, exhibiting similar variation trend with the results by blood gas analyzer. Studies in living rabbit display the reasonable and favorable feasibility of capillary sensing system in real-time arterial blood gas analysis. Overall, the multifunctional fluorescent capillary sensing system exhibits significant potential in real-time arterial blood gas analysis and clinical application of disease diagnosis.
In this paper, a new flame retardant synergist PSil-CS was successfully synthesized, which was combined with flame retardant ammonium polyphosphate (APP) to flame retardant Unsaturated polyester resin (UPR) composites. When the weight ratio of APP: PSil-CS is 30:1 and 15:1, the UL 94 V-0 level can be achieved. When the weight ratio of APP: PSil-CS is 15:1, the UPR showed a good flame retardant promotion effect, the LOI value was up to 35.1 %, the peak heat release rate (pk-HRR) was 70.45 % lower than that of pure UPR sample, and 30.4 % lower than that of UPR/APP-16 % sample. Under the premise that the total amount of flame retardants is unchanged, although the total amount of phosphorus is reduced by replacing APP with PSil-CS, it is found in TGIR test that the addition of PSil-CS can promote the flame retarding effect of phosphorus by generating more PO· and PO2· free radicals. These free radicals can capture the free radicals released by the UPR matrix during the combustion process, thus interrupting the chain reaction of the combustion of UPR composites and reducing the combustion intensity of the composites. Adding PSil-CS can promote the carbonization of the UPR matrix and increase the utilization efficiency of the P element. The silicon element can also form a silicon-containing protective layer on the surface to improve the thermal stability of the surface char layer. At the same time, the addition of phosphosilane-modified PSil-CS can effectively improve the bending strength of the composites.
An intrinsic flame-retardant epoxy resin was synthesized by introducing biphenyl structures and phosphorous into epoxy resin. The biphenyl structures could increase the glass transition temperature by more than 10 °C, as well thermal stability as indicated by the elevation in char yield. They could also enhance mechanical properties as reflected by the increments of 86.4% and 176.5% in tensile strength and breaking elongation, respectively, and offset the negative effects of phosphorus-containing structures. The introduction of elemental phosphorus could improve the flame-retardant properties of epoxy resin. The resulting epoxy resin presented a high limiting oxygen index of 32.4% and a V-0 rating in the UL-94 test. Moreover, it exhibited better flame-retardant parameters than pure epoxy resin in the cone calorimeter test. It could be decomposed to generate PO∙ and PO 2 ∙ radicals to quench active free radicals, reduce toxic and smoke gas generation, and form a dense and stable char layer. It could simultaneously achieve gas and condensed phase flame retardancy. The presence of the biphenyl structure and phosphorus element in the epoxy resin system improved the thermal, mechanical, and flame-retardant properties of epoxy resin simultaneously. This work offered a facile method for preparing intrinsic phosphorus-containing flame-retardant epoxy resin without sacrificing thermal and mechanical properties.
危险品化学品经营许可证（带存储）