The growth conditions and mechanism of SiC whiskers synthesized by carbothermal reductionof silica are described in the present paper. This method was used for preparing SiC whiskers which dis-tributed homogeneously i...The growth conditions and mechanism of SiC whiskers synthesized by carbothermal reductionof silica are described in the present paper. This method was used for preparing SiC whiskers which dis-tributed homogeneously in the matrix of Si_3N_4 powders, and then Si_3N_4 composites with SiC reinforcedwhisker were prepared (Since no additional whiskers are needed ,this kind of materials may be referred to as“self-reinforced ceramicbased composites”). These composites have good mechanical properties at 15 vol. %SiC_W : K_(1C)= 8. 0 MPa· m￣(1/2);σ_(b,RT)=649 MPa;σ_(b,1300℃)=621 MPa (after oxidation at 1300 ℃ for 100h inair). The microstructural characteristics of SiC/ Si_3N_4 composrtes are: SiC whiskers are homogeneously dis-tributed between Si_3N_4 grains,in which there are nanometer-sized SiC particals trapped,and only a few ofthem are located at Si_3N_4 grain boundaries.展开更多
A facile process to prepare self-reinforced antibacterial paper(SRAP)was developed by in situ synthesis of zinc oxide(ZnO)in partially dissolved cellulose.The SRAP was fabricated by impregnating filter paper in zinc c...A facile process to prepare self-reinforced antibacterial paper(SRAP)was developed by in situ synthesis of zinc oxide(ZnO)in partially dissolved cellulose.The SRAP was fabricated by impregnating filter paper in zinc chloride(ZnCl_(2))solution and then reacting with sodium hydroxide(NaOH).Filter paper was firstly impregnated with ZnCl_(2) solution of 65 wt%concentration for 5 seconds at 80℃,and then pressed at 3.85 kPa for 5 seconds to remove excess liquid.Subsequently,the paper was soaked in a 0.8 wt%NaOH solution for 1 hour,and then washed with deionized water,and dried finally to yield SRAP.Energy dispersive X-ray spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS)and scanning electron microscope(SEM)were used to characterize the SRAP.The results revealed that the SRAP contained intact cellulose fibers as the skeleton,gelled cellulose as the matrix,and clusters of nano ZnO particles as the filler.The SRAP had a much higher density,tensile and burst strength,compared with the untreated cellulose paper,and the folding strength was enhanced by more than fifteen times.In addition,the SRAP had outstanding antibacterial properties due to the presence of nano ZnO particles.展开更多
文摘The growth conditions and mechanism of SiC whiskers synthesized by carbothermal reductionof silica are described in the present paper. This method was used for preparing SiC whiskers which dis-tributed homogeneously in the matrix of Si_3N_4 powders, and then Si_3N_4 composites with SiC reinforcedwhisker were prepared (Since no additional whiskers are needed ,this kind of materials may be referred to as“self-reinforced ceramicbased composites”). These composites have good mechanical properties at 15 vol. %SiC_W : K_(1C)= 8. 0 MPa· m￣(1/2);σ_(b,RT)=649 MPa;σ_(b,1300℃)=621 MPa (after oxidation at 1300 ℃ for 100h inair). The microstructural characteristics of SiC/ Si_3N_4 composrtes are: SiC whiskers are homogeneously dis-tributed between Si_3N_4 grains,in which there are nanometer-sized SiC particals trapped,and only a few ofthem are located at Si_3N_4 grain boundaries.
基金support of the National Natural Science Foundation of China (No.31570576 and No.31270629)the Innovation Training Program for Jiangsu College Students (China) (No.201410298056Z)Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources,Nanjing Forestry University (China).
文摘A facile process to prepare self-reinforced antibacterial paper(SRAP)was developed by in situ synthesis of zinc oxide(ZnO)in partially dissolved cellulose.The SRAP was fabricated by impregnating filter paper in zinc chloride(ZnCl_(2))solution and then reacting with sodium hydroxide(NaOH).Filter paper was firstly impregnated with ZnCl_(2) solution of 65 wt%concentration for 5 seconds at 80℃,and then pressed at 3.85 kPa for 5 seconds to remove excess liquid.Subsequently,the paper was soaked in a 0.8 wt%NaOH solution for 1 hour,and then washed with deionized water,and dried finally to yield SRAP.Energy dispersive X-ray spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS)and scanning electron microscope(SEM)were used to characterize the SRAP.The results revealed that the SRAP contained intact cellulose fibers as the skeleton,gelled cellulose as the matrix,and clusters of nano ZnO particles as the filler.The SRAP had a much higher density,tensile and burst strength,compared with the untreated cellulose paper,and the folding strength was enhanced by more than fifteen times.In addition,the SRAP had outstanding antibacterial properties due to the presence of nano ZnO particles.
