The viscous-flow properties of pectin from the residue of orange peel after extraction of essential oil and flavonoid were studied and the viscosity-average molecular mass(Mv,ave) of this kind of pectin was determined...The viscous-flow properties of pectin from the residue of orange peel after extraction of essential oil and flavonoid were studied and the viscosity-average molecular mass(Mv,ave) of this kind of pectin was determined.Experimental results show that Arrhenius viscous-flow equation can be applied to describing the effect of temperature on viscosity of this kind of orange peel pectin solutions with the average viscous-flow activation energy being 17.91 kJ/mol(depending on the concentration).Neither power equation,η =K1 cA1,nor exponential equation,η=K2exp(A2c) can describe the effect of concentration on viscosity of this kind of orange peel pectin solutions well.However,it seems that exponential equation model is more suitable to describe their relation due to its higher linear correlation coefficient.Schulz-Blaschke equation can be used to calculate the intrinsic viscosity of this kind of orange peel pectin.The Mv,ave of the orange peel pectin is 1.65×105 g/mol.展开更多
Benzoguanamine formaldehyde (BG F) resins are a class of amino resins, which are important cross linking agents for epoxy, alkyol and acrylic resins, etc. The cross linking performance is the best one when the polymer...Benzoguanamine formaldehyde (BG F) resins are a class of amino resins, which are important cross linking agents for epoxy, alkyol and acrylic resins, etc. The cross linking performance is the best one when the polymerization degree is 2 4. This paper discusses the effects of the pH value for polycondensation and the formaldehyde to benzoguanamine mole ratio in a methanol system, and compares the relative molecular mass distribution using the Flory statistics method.展开更多
YB-2 aviation polymethyl methacrylate (PMMA) is irradiated in a xenon arc lamp weather resistance test chamber for 1620 hours. The tensile strength, light transmittance, surface morphology, relative molecular mass, in...YB-2 aviation polymethyl methacrylate (PMMA) is irradiated in a xenon arc lamp weather resistance test chamber for 1620 hours. The tensile strength, light transmittance, surface morphology, relative molecular mass, infrared absorption spectrum and glass transition temperature (Tg) of PMMA exposed in xenon arc lamp for different durations are tested and characterized by universal testing machine, optical haze instrument, scanning electronic microscopy (SEM), gel permeation chromatograph (GPC), fourier transform infrared spectrometer (FT-IR) and differential scanning calorimetry (DSC), so as to comprehensively analyze the influence of xenon arc lamp irradiation on the performance of PMMA. The results reveal that under the effect of 1620 hours xenon arc lamp irradiation and periodic spraying water, the light transmittance and glass transition temperature do not change significantly, and no new chemical group is produced. After irradiated 360 hours, tiny cracks occur in the surface of PMMA, indicating that they occur at a certain degree of degradation, meanwhile, the main chain may be broken and the relative molecular mass of surface of the material decreases. After exposure of 720 hours, the tensile strength decreases about 30%.展开更多
基金Project(104-0071) supported by Foundation of Talents of Central South University of Forestry and Technology,China
文摘The viscous-flow properties of pectin from the residue of orange peel after extraction of essential oil and flavonoid were studied and the viscosity-average molecular mass(Mv,ave) of this kind of pectin was determined.Experimental results show that Arrhenius viscous-flow equation can be applied to describing the effect of temperature on viscosity of this kind of orange peel pectin solutions with the average viscous-flow activation energy being 17.91 kJ/mol(depending on the concentration).Neither power equation,η =K1 cA1,nor exponential equation,η=K2exp(A2c) can describe the effect of concentration on viscosity of this kind of orange peel pectin solutions well.However,it seems that exponential equation model is more suitable to describe their relation due to its higher linear correlation coefficient.Schulz-Blaschke equation can be used to calculate the intrinsic viscosity of this kind of orange peel pectin.The Mv,ave of the orange peel pectin is 1.65×105 g/mol.
文摘Benzoguanamine formaldehyde (BG F) resins are a class of amino resins, which are important cross linking agents for epoxy, alkyol and acrylic resins, etc. The cross linking performance is the best one when the polymerization degree is 2 4. This paper discusses the effects of the pH value for polycondensation and the formaldehyde to benzoguanamine mole ratio in a methanol system, and compares the relative molecular mass distribution using the Flory statistics method.
文摘YB-2 aviation polymethyl methacrylate (PMMA) is irradiated in a xenon arc lamp weather resistance test chamber for 1620 hours. The tensile strength, light transmittance, surface morphology, relative molecular mass, infrared absorption spectrum and glass transition temperature (Tg) of PMMA exposed in xenon arc lamp for different durations are tested and characterized by universal testing machine, optical haze instrument, scanning electronic microscopy (SEM), gel permeation chromatograph (GPC), fourier transform infrared spectrometer (FT-IR) and differential scanning calorimetry (DSC), so as to comprehensively analyze the influence of xenon arc lamp irradiation on the performance of PMMA. The results reveal that under the effect of 1620 hours xenon arc lamp irradiation and periodic spraying water, the light transmittance and glass transition temperature do not change significantly, and no new chemical group is produced. After irradiated 360 hours, tiny cracks occur in the surface of PMMA, indicating that they occur at a certain degree of degradation, meanwhile, the main chain may be broken and the relative molecular mass of surface of the material decreases. After exposure of 720 hours, the tensile strength decreases about 30%.
