Effects of polyelectrolytes on the hardness of borax decahydrate crystals

Year 2019, Volume: 4 Issue: 4, 172 - 179, 31.12.2019

Sevgi Polat Perviz Sayan

https://doi.org/10.30728/boron.511783

Cited By: 1

Abstract

The hardness of borax decahydrate crystals was
measured using cationic polyelectrolytes of FO4115, FO4400 and FO4990 with
anionic polyelectrolytes of AN923, AN930 and AN999 as an additive. The
measurements were carried out in the indentation load range of 10 g to 30 g. It
was determined that the Vickers hardness (H_V) decreased with
increasing applied load, showing that the borax decahydrate crystals exhibited
an indentation size effect. Vickers microhardness measurements revealed that
pure borax decahydrate crystals had a brittle structure, yet the crystals
obtained in additive media were categorized as a soft material. The
proportional specimen resistance model was applied to determine the
load-independent microhardness. The crystal hardness of borax decahydrate was
found to change depending on the type and concentration of polyelectrolyte
used. In addition to the mechanical properties, the thermal and physical
characteristics of borax decahydrate crystals were investigated by
thermogravimetric and Fourier transform infrared spectroscopy analysis. The
characterization results confirmed that the polyelectrolytes were adsorbed on
the crystal’s surface.

Keywords

Borax decahydrate, crystal hardness, polyelectrolyte, PRS model

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