Relaxation properties of enamel slips

Translated from Steklo i Keramika, No. 3, p. 27, March, 1992.     

含TiO_2的PET的流变性能研究

采用毛细管流变仪研究了含二氧化钛(TiO2)的聚对苯二甲酸乙二醇酯(PET)的流变性能,计算得到非牛顿指数(n)和粘流活化能(Eη)。结果表明:含TiO2的PET所能达到的最高剪切速率高于纯PET,其剪切粘度、纺丝温度及纺丝速度均高于纯PET;在280,285,290℃时,含TiO2的PET的n小于纯PET,295℃时,大于纯PET;含质量分数0.32%TiO2的PET的Eη与纯PET相当,含质量分数2.50%TiO2的PET的Eη远低于纯PET。     

Rheological and casting properties of ceramic slips

Translated from Steklo i Keramika, No. 3, pp. 22–25, March, 1991.     

Some aspects of technical instability of enamel slips

Translated from Steklo i Keramika, No. 4, pp. 26–27, April, 1990.     

Rheological behavior of LDPE/CaCO3 blends containing EAA

Calcium carbonate (CaCO₃) filler particles were surface treated with organic titanate (TTS), a coupling agent. The composites were prepared by blending low‐density polyethylene (LDPE) with the surface‐modified fillers at various weight ratios. Ethylene‐acrylic acid copolymer (EAA) was added to improve the adhesion of LDPE to fillers. A capillary rheometer was used to evaluate rheological properties of the LDPE/CaCO₃/EAA blends. The blends were shown to be pseudoplastic with shear thinning behavior. When CaCO₃ was modified by TTS (<2 wt%), the viscosity of the blends decreased quickly, and, addition of a small amount of EAA (<6 wt%) could also decrease the viscosity of the blends. The thermal behavior of these materials is evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of a small amount of EAA and TTS enhances the stabilization of the blends, which could be explained by the “ball belling” action. The effects of temperature, TTS content, CaCO₃ granule size, and content on the rheological property were also studied. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Increasing the stability of enamel slips for composite coatings

Translated from Steklo i Keramika, No. 3, pp. 25–26, March, 1992.     

Rheological behavior of partially hydrolyzed poly(vinyl acetate-co-ethylene)

The rheological behavior of partially hydrolyzed poly(vinyl acetate-co-ethylene) (VAE) was investigated, using a Rheometrics Dynamic Mechanical Spectrometer. For the investigation, measurements of storage modulus (G′), loss modulus (G″) and loss tangent (tan δ) of the materials were recorded as functions of temperature at a fixed frequency (i.e., using temperature scans) and, also, as functions of frequency at a fixed temperature (i.e., using frequency scans). For the hydrolysis, three different grades of copolymer (containing 34, 47, 62 mol% of vinyl acetate) were used to yield poly(vinyl acetate-co-ethylene-co-vinyl alcohol) (VAEOH) with varying amounts of hydroxyl group. For comparison purposes, the viscoelastic properties of blends of VAE copolymer with poly(vinyl alcohol) (PVOH), having varying blend compositions, were also measured. The blends were prepared by first mixing a solution of VAE copolymer, which was dissolved in a toluene/dichloroethane mixed solvent, and an aqueous solution of PVOH, and then freeze drying the mixture to a constant weight. Also measured were the glass transition temperature (T_g) of the VAE copolymers and the T_g and melting point (T_m) of the VAEOH terpolymers, using a DuPont Thermal Analyzer equipped with a 910 DSC Module. It has been found that (1) introduction of hydroxyl group into the backbone of the amorphous VAE copolymer has made the resulting VAEOH terpolymer semicrystalline; (2) the T_m, T_g, G′, and the complex viscosity (η^*) of the VAEOH terpolymers increase with increasing amounts of hydroxyl group; (3) the physical blending of PVOH with VAE copolymer has not affected the T_g of the VAE copolymer; (4) the G′ and η^* of the VAE/PVOH blends are found to increase with the amount of PVOH in the blend. The use of logarithmic plots of G′ versus G″ has been found to be very useful for discerning the differences in the structure of the materials tested.     

Rheological and technological properties of chromic oxide slips and castings

Conclusions An investigation of the rheological properties of chromic oxide slips showed that their optimum casting interval lies in an acid medium at pH not above 3. In this case the zeta potential is at maximum, the viscosity at minimum, and the building-up rate and density of the casting high.Firing in a mild reducing medium gave chromic oxide specimens of porosity 14–16% and a cold-crushing strength of 1300–1700 kg/cm².Translated from Ogneupory, No. 2, pp. 42–46, February, 1976.