Some known and new hexaaryloxyphosphazene: N3P3(O-C6H4-R)(1)/(R=H.CH.OCH3. C(CH3)(3). CHO.F.C6H5COOR. etc) were readily obtained with ca. 70% isolated yield in refluxing acetonitriie in the presence of anhydrous potas...Some known and new hexaaryloxyphosphazene: N3P3(O-C6H4-R)(1)/(R=H.CH.OCH3. C(CH3)(3). CHO.F.C6H5COOR. etc) were readily obtained with ca. 70% isolated yield in refluxing acetonitriie in the presence of anhydrous potassium phosphate. All compounds were characterized by means of elemental analysis. H-1-NMR.P-31-NMR sprctroscopy.展开更多
Magnesium and potassium phosphate cement （MKPC） sample were prepared by mixing dead burnt MgO powder, potassium phosphate and different dosages of retarder borax to investigate the effect of borax on its hydration a...Magnesium and potassium phosphate cement （MKPC） sample were prepared by mixing dead burnt MgO powder, potassium phosphate and different dosages of retarder borax to investigate the effect of borax on its hydration and hardening characteristics. The pH value, fluidity, hydration temperature and strength development of MKPC paste were investigated, and the mineralogical composition and microstructural morphology of its hydration products were analyzed. The experimental results indicated that, within a certain dosage, borax caused an endothermal effect for MKPC paste, which decreased the early hydration rate of MKPC paste, increased the fluidity of MKPC paste. Thus, strength and micro-morphology of hardened MKPC are affected. It can be concluded that borax in MKPC paste retards the early hydration rate of MKPC paste by forming a film onto surface of MgO, decreasing the temperature and increasing the pH value of the system. As borax dosage varying, different factors may dorminate the effects.展开更多
基金We are grateful to the National Natural Science Foundation of China (grant NO. 59825116) and Chinese Academy of Sciences for the
文摘Some known and new hexaaryloxyphosphazene: N3P3(O-C6H4-R)(1)/(R=H.CH.OCH3. C(CH3)(3). CHO.F.C6H5COOR. etc) were readily obtained with ca. 70% isolated yield in refluxing acetonitriie in the presence of anhydrous potassium phosphate. All compounds were characterized by means of elemental analysis. H-1-NMR.P-31-NMR sprctroscopy.
文摘Magnesium and potassium phosphate cement （MKPC） sample were prepared by mixing dead burnt MgO powder, potassium phosphate and different dosages of retarder borax to investigate the effect of borax on its hydration and hardening characteristics. The pH value, fluidity, hydration temperature and strength development of MKPC paste were investigated, and the mineralogical composition and microstructural morphology of its hydration products were analyzed. The experimental results indicated that, within a certain dosage, borax caused an endothermal effect for MKPC paste, which decreased the early hydration rate of MKPC paste, increased the fluidity of MKPC paste. Thus, strength and micro-morphology of hardened MKPC are affected. It can be concluded that borax in MKPC paste retards the early hydration rate of MKPC paste by forming a film onto surface of MgO, decreasing the temperature and increasing the pH value of the system. As borax dosage varying, different factors may dorminate the effects.
