Rheological properties of polyvinyl butyral/Pluronic F127/PEG200 blend systems

The influence of temperature and mass fraction of Pluonic F127 on the rheological properties of polyvinyl butyric （PVB）/Pluronic F127/polyethylene glycol （PEG） 200 blend systems was investigated by a rotational rheometer with parallel plates. The results show that the blend systems approach homogeneous state at 140, 150 and 160℃while the rheological properties of the blend systems significantly deviate from the homogeneous systems at 120℃. Shear thinning behavior is observed for all the blend systems at different temperatures and is enhanced by increasing Pluronic F127 content. The complex viscosity, storage modulus, loss modulus, zero-shear activation energy and flow recovery of the blend systems increase with the increase of Pluronic F127 content. There is a crossing point for the loss modulus and the storage modulus of each sample at high frequency, which is called specified frequency （SF）. The loss modulus is larger than the storage modulus when the frequency is less than the SF, and when frequency is more than SF, the loss modulus is smaller than the storage modulus.

Fabrication of ZrO_2/Mo-Si/Ni Functionally Graded Material by Dip-Coating

A slurry dip-coating technique was developed for fabrication of Zr02/Mo-Si/Ni functionally graded material (FGM)on the stainless steel substrate. The rheological behavior of ZrO2-Ni-ethanol slurry was characterized by viscositytest. The amount of polyvinyl butyral (PVB) additives, which served as the dispersant and binder in ZrO2-Ni-ethanolslurry, was optimized. The results showed that the characters of mixed slurries with added 9 vol. pct (relativelyto total powders) MoSi2 powders prepared by mechanical alloying changed little. The stainless steel substrate wascoated several times by dipping in the slurries, and followed by drying in air every dipping. After debinding in Arin graphite die, the coated FGM plate was finally hot pressed at 1300℃ for 1 h under the pressure of 5 MPa in Arin the same die. Microstructural observations of the sintered FGM specimens revealed that the graded layers wereformed on the stainless steel substrate, in which no cracks were observed.

Highly sensitive potentiometric immunosensor for hepatitis B surface antigen diagnosis

A highly sensitive potentiometric immunosensor for the diagnoses of epidemic dis-eases has been developed by means of self-assembly to immobilize hepatitis B surface antibody(HBsAb)for the detection of hepatitis B surface antigen(HBsAg)as a model.At first,the Nafion containing-SO^(-)_(3)groups was immobilized on a platinum electrode surface to absorb the-NH^(+)_(3)groups of antibody molecules via the opposite-charged adsorption technique,in the meantime,hepatitis B surface antibodies were adsorbed onto the surface of Au nanoparticles,then hepatitis B surface antibodies and Au nanopartilces were entrapped into polyvinyl butyral on the surface of Nafion film.The modified procedure was further characterized by electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).The influence and factors influencing the per-formance of resulting immunosensor were studied in detail.The resulting immunosensor exhib-ited sigmoid curve with log HBsAg concentrations,high sensitivity,wide linear range from 26 to 1280 ng·mL^(-1)with a detection limit of 3.1 ng·mL^(-1),rapid potentiometric response(<3 min)and long-term stability(>4 months).Analytical results of clinical samples show that the developed immunoassay is comparable with the enzyme-linked immunosorbent assays(ELISAs)method,implying a promising alternative approach for detecting HBsAg in the clinical diagnosis.