Preparation, Characterisation, and Application of Bifunctional BaSO(4) Sheets

Barium sulfate (BaSO(4)) is a material with high reflectance for preparing bifunctional sheets used in dry reagent chemical tests. In this study, bifunctional BaSO(4) sheets with scattering power and high reflectance were prepared with BaSO(4) microspheres sized 1.3~1.8 μm and cellulose acetate (CA). Factors such as the BaSO(4) morphology, CA dosage, mixing time, surfactant, solid content and wet sheet thickness were investigated. Scanning electron microscopy (SEM), a dynamic contact angle test, light reflection detector and light reflection densitometer were employed to characterize the structure and properties of bifunctional BaSO(4) sheets. The optimal conditions for preparing bifunctional BaSO(4) sheets under natural drying conditions were as follows: mass ratio of CA to BaSO(4) microspheres was 0.03:1; mixing acetone solution was used to form liquid stock puree; 35 μL Tween-80 was used to improve the hydrophilicity of bifunctional sheets; solid content was 54.9%; mixing 2 h then 450 µm thick sheets were cast on a glass plate using a film applicator. The light reflectance value of bifunctional BaSO(4) sheets in the range of 400~800 nm was higher than 97%. Serum diffused in bifunctional BaSO(4) sheets reacted in reagent sheets and formed uniform colorful spots. Considering the repeatability of spot proportion and light reflectance value, the sheet offered a uniform serum scattering power and good repeatability. Therefore, the bifunctional BaSO(4) sheets are regarded as a promising material for dry chemical diagnostic reagents.