The use of a Polany type dynamometer for investigating the mechanical properties of biopolymer gels under simple shearing

Abstract

Application of the method of spherical indentor penetration and the method of axialdeformation of ringshaped sample (Pochettino viscometer) for studying the mechanical properties of biopolymer gels under simple shearing is described. A standard Polany dynamometer equipped with special adapters was used in the investigation. A universal mould to prepare samples has been suggested. The problem of deaeration and reproducibility of the geometric parameters of the samples has been solved and the quality of their working surfaces has been improved considerably. A comparative study of the mechanical properties of aqueous gelatine gels of varied concentration (2–17.6%) was performed under a constant loading rate to illustrate some of the possibilities of the methods. The agreement of the results of both methods could be ensured. The techniques described possess several valuable advantages, namely low labour‐ and material consumption, high accuracy, simplicity of sample preparation, and possibility of conducting experiments in the stress relaxation mode and under constant loading rate.