Considering that copper mine tailings(CMTs)are commonly mixed with ordinary Portland cement,fly ash(FA),and kaolin to produce geopolymers,to make full use of CMTs,the properties of geopolymers manufactured under diffe...Considering that copper mine tailings(CMTs)are commonly mixed with ordinary Portland cement,fly ash(FA),and kaolin to produce geopolymers,to make full use of CMTs,the properties of geopolymers manufactured under different material mass ratios and curing methods(standard curing,water bath curing,and 60℃curing)are evaluated with significantly increased dosage of CMTs.Porosity and unconfined compressive strength tests,X-ray diffraction,field emission scanning electron microscopy,and energy dispersive spectroscopy are used to determine the physical and mechanical properties,microstructure,and mineral composition of geopolymers.Finally,costs and CO 2 emissions of specimens with different material mass ratios during the preparation processes are compared.The results show that during the geopolymerization of low-calcium materials,various geopolymer gels,including calcium silicate,calcium silicoaluminate,and mainly sodium silicoaluminate gels,coexist.The solid waste,cost,and carbon dioxide emission reductions can reach 100%,166.3 yuan/t,and 73.3 kg/t,respectively.Under a curing condition of 60℃,the sample with a CMTs mass fraction of 70%and an FA mass fraction of 30%meets the requirements of porosity,compressive strength.The resource utilization of CMT and FA is realized in a more economical way.展开更多
A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR ...A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR （nuclear magnetic resonanse） spectroscopy and the dependence of the cured materials properties on the composition was established. Increase of a propargyl content resulted in char yield raise and the maximum value had been found for propargylated resin--58%. DSC （differential scanning calorimetry）-analysis of the resins has demonstrated that exothermic enthalpy of the curing process could be adjusted by varying the content of propargyl and allyl groups in the resin.展开更多
基金The National Natural Science Foundation of China(No.41877240)Scientific Research Foundation of Graduate School of Southeast University(No.YBPY1930).
文摘Considering that copper mine tailings(CMTs)are commonly mixed with ordinary Portland cement,fly ash(FA),and kaolin to produce geopolymers,to make full use of CMTs,the properties of geopolymers manufactured under different material mass ratios and curing methods(standard curing,water bath curing,and 60℃curing)are evaluated with significantly increased dosage of CMTs.Porosity and unconfined compressive strength tests,X-ray diffraction,field emission scanning electron microscopy,and energy dispersive spectroscopy are used to determine the physical and mechanical properties,microstructure,and mineral composition of geopolymers.Finally,costs and CO 2 emissions of specimens with different material mass ratios during the preparation processes are compared.The results show that during the geopolymerization of low-calcium materials,various geopolymer gels,including calcium silicate,calcium silicoaluminate,and mainly sodium silicoaluminate gels,coexist.The solid waste,cost,and carbon dioxide emission reductions can reach 100%,166.3 yuan/t,and 73.3 kg/t,respectively.Under a curing condition of 60℃,the sample with a CMTs mass fraction of 70%and an FA mass fraction of 30%meets the requirements of porosity,compressive strength.The resource utilization of CMT and FA is realized in a more economical way.
文摘A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR （nuclear magnetic resonanse） spectroscopy and the dependence of the cured materials properties on the composition was established. Increase of a propargyl content resulted in char yield raise and the maximum value had been found for propargylated resin--58%. DSC （differential scanning calorimetry）-analysis of the resins has demonstrated that exothermic enthalpy of the curing process could be adjusted by varying the content of propargyl and allyl groups in the resin.
