The gel and sol parts in epoxidized natural rubber(ENR) were separated with toluene and 2-pentanone, respectively, and their thermal aging behaviour were studied by FTIR spectrometry. The results indicate that the car...The gel and sol parts in epoxidized natural rubber(ENR) were separated with toluene and 2-pentanone, respectively, and their thermal aging behaviour were studied by FTIR spectrometry. The results indicate that the carbon-carbon double bonds and the epoxy bonds in both gel and sol are destroyed successively on aging process, accompanied with the occurance of the hydroxyl, ether, carbonyl of aldehyde and ketone groups. Along with prolonging the aging time, the aldehyde and ketone are further converted into ester structures. These changes of the functional groups demonstrate the gel is less thermostable than sol in ENR.展开更多
The effects of alkali oxides （Na2O and K2O addition on both the sintering behavior and dielectric properties of Ca-AI-B-Si-O glass/Al2O3 composites were investigated by Fourier transform infrared spectroscopy （FTIR...The effects of alkali oxides （Na2O and K2O addition on both the sintering behavior and dielectric properties of Ca-AI-B-Si-O glass/Al2O3 composites were investigated by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimeter （DSC）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of alkali oxides in the glass causes the decrease of [SiO4], which results in the decrease of the continuity of glass network, and leads to the decrease of the softening temperature Tf of the samples and the increasing trend of crystallization. And that deduces corresponding rise of densification, dielectric constant, dielectric loss of the low temperature co-fired ceramic （LTCC） materials and the decrease of its thermal conductivity. By contrast, the borosilicate glass/A1203 composites with 1.5% （mass fraction） alkali oxides sintered at 875 ℃ for 30 rain exhibit better properties of a bulk density of 2.79 g/cm3, a porosity of 0.48%, a 2 value of 2.28 W/（m.K）, a er value of 7.82 and a tand value of 9.1 × 10-4 （measured at 10 MHz）.展开更多
文摘The gel and sol parts in epoxidized natural rubber(ENR) were separated with toluene and 2-pentanone, respectively, and their thermal aging behaviour were studied by FTIR spectrometry. The results indicate that the carbon-carbon double bonds and the epoxy bonds in both gel and sol are destroyed successively on aging process, accompanied with the occurance of the hydroxyl, ether, carbonyl of aldehyde and ketone groups. Along with prolonging the aging time, the aldehyde and ketone are further converted into ester structures. These changes of the functional groups demonstrate the gel is less thermostable than sol in ENR.
基金Project(2007AA03Z0455) supported by the National High Technology Research and Development Program ("863" Program) of ChinaProject(BE2010194) supported by Science & Technology Pillar Program of Jiangsu in China+3 种基金Project(BE2009168) supported by Science & Technology Pillar Program of Jiangsu in ChinaProject supported by the Priority Academic Program Development (PAPD) of Jiangsu Higher Education InstitutionsProject(KF201103) supported by State Key Laboratory of New Ceramic and Fine Processing Tsinghua UniversityProject(CXZZ12_0415) supported by Innovation Foundation for Graduate Students of Jiangsu Province,China
文摘The effects of alkali oxides （Na2O and K2O addition on both the sintering behavior and dielectric properties of Ca-AI-B-Si-O glass/Al2O3 composites were investigated by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimeter （DSC）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of alkali oxides in the glass causes the decrease of [SiO4], which results in the decrease of the continuity of glass network, and leads to the decrease of the softening temperature Tf of the samples and the increasing trend of crystallization. And that deduces corresponding rise of densification, dielectric constant, dielectric loss of the low temperature co-fired ceramic （LTCC） materials and the decrease of its thermal conductivity. By contrast, the borosilicate glass/A1203 composites with 1.5% （mass fraction） alkali oxides sintered at 875 ℃ for 30 rain exhibit better properties of a bulk density of 2.79 g/cm3, a porosity of 0.48%, a 2 value of 2.28 W/（m.K）, a er value of 7.82 and a tand value of 9.1 × 10-4 （measured at 10 MHz）.
