JOURNAL OF PLASTIC FILM AND SHEETING, cilt.0, sa.0, ss.1-19, 2022 (SCI-Expanded)
This study is on polyethylene terephthalate (PET) compounded with magnesium borate
(MB) (Mg2B2O5) powders between (0.2–3.2% by weight) which were synthesized via solgel technique at laboratory-scale. The MB/PET composites were characterized in terms of
chemical, thermal degradation, and mechanical properties. Their phases and chemical
structures were identified by X-ray Diffraction and Fourier Transform Infrared analyses.
The MB added into PET matrix significantly reduced PET degrading to acetaldehyde,
carboxylic acids and diethylene glycol. However, while at 0.2 wt.% MB isophthalic acid
(IPA) decreased and at higher MB concentrations there were higher IPA levels. The added
MB increased the composites intrinsic viscosity (IV) compared to the pure PET. The
highest IV (0.701 dL/g) was at the 0.2 wt.% MB/PET composite. Both Tg and Tm temperatures trended down up to 3.2 wt.% MB. Compared to pure PET, glass transition
temperature (Tg) decreased to 80.4°C (at 3.2 wt.% MB) from 81°C, whereas melt
temperature (Tm) decreased to 248.5°C (at 3.2 wt.% MB) from 249.4°C. The MB/PET composite tensile strength increased by 11.31% to a 60 MPa maximum at 0.2 wt.% MB
compared to neat PET (53.9 MPa). However, at 0.4 wt. % and higher MB the dispersion
was insufficient causing the MB powders to aggregate in the PET matrix, resulting in
reduced tensile strength.