STYRENE-BUTADIENE THERMOPLASTICS AS THE BASIS OF ADHESIVE COMPOSITIONS

Abstract

The physicochemical and adhesive properties of styrene-butadiene thermoplastic elastomers (SBS) with different styrene content, structure, and melt flow index (MFI) were studied. The heat resistance was determined by the method of thermogravimetric analysis (TGA) using the device «Derivatograph-C» (MOM, Hungary) at a heating rate of 10 °C/min in air. The thermal stability of the SBS was evaluated by the temperatures of 5 and 10 % weight loss of the samples. To determine the features of the glass transition process and the value of the glass transition temperature T_g, the method of differential scanning calorimetry (DSC), the DSC-822e device (Mettler-Toledo, Switzerland) was used in the temperature range from –90 to 170 °C at a heating rate of 20 °C/min in argon medium. The tests were carried out using two modes: heating-cooling to 20 °C and heating. The viscosity of the adhesive (SBS solutions with special additives in methylene chloride) was also determined according to GOST8420-74. The adhesive properties were determined by the bond strength during delamination according to GOST 28966.1-91 with adhesives based on SBS samples of standard model rubber based on SBR 1502. It is shown that the lower the MFI, the higher the thermal stability of the SBS. Variation of the polystyrene domains T_g when changing the styrene content for SBS sample are presented. Statistical processing of experimental data on the adhesive strength was carried out. Representation of the relationship between SBS structure and adhesive and other properties are discussed.