Influence of X-ray opaque BaSO4 nanoparticles on the mechanical, thermal and rheological properties of polyoxymethylene nanocomposites

Abstract

This work evaluates the infl uence of a radiopaque reinforcement, barium sulfate (BaSO 4 ), on the mechanical, rheological and thermal properties of polyoxymethylene (POM). Nanocomposites of POM containing spherical nanoparticles of BaSO 4 (0, 1, 2, 3 phr) were obtained by melt extrusion in a twin-screw equipment followed by injection molding. The mechanical, thermal and rheological properties of these nanocomposites and the dispersion state of the particles were investigated. Scanning and transmission electron microscopy revealed the morphology of the products. The main objective of this work is the production of nanocomposites with sulfate concentration enough to acquire radiopaque properties while maintaining the mechanical properties of the matrix. In this regard, mechanical and rheological properties were found similar to those of the polymer matrix, but radiopaque contrast tests revealed the infl uence of the nanoparticles concentration on the optical properties of the composites. The production of these nanocomposites suggests potential applications in the biomedical sector given their unique radioopacity properties.

Investigation on the environmental‐friendly poly(lactic acid) composites based on precipitated barium sulfate: Mechanical, thermal properties, and kinetic study of thermal degradation

“…Similar results have been demonstrated elsewhere in the composites of PLA/calcium sulfate and polyoxymethylene/BaSO 4. However, de Arenaza and his co‐workers claimed that the elongation‐at‐break of PLA composites could be significantly heightened by 3338% using BaSO 4 with the larger size of 0.75–1 μm. Such tremendous divergence should be explained by the effect of particle size because the particle size employed in present experiments is smaller than 0.7 μm, which might prefer to enhance the elastic modulus rather than the toughness under quasi‐state stress …”

“…In contrast, the tensile strength is declined steadily, showing a maximum reduction of around 30% at 25% BaSO 4 when compared to unfilled sample. The similar negative influence of BaSO 4 on the tensile strength has also been reported by Romero‐Ibarra and Wang et al Previous studies have demonstrated that the tensile strength of PLA composites is affected by many factors of filler loading, particle size, interfacial adhesion, and so on, while Fu and his co‐workers have claimed that the inorganic filler with short length preferring to enhance the elastic modulus rather than tensile strength. In our previous report, the average diameter of BaSO 4 employed in our study is ranged from 0.20 to 0.38 μm, which is too small to bear the applying stress effectively.…”

“…It is delighted to found that all the composites exhibit the higher values of impact toughness than pristine PLA, indicating that the incorporated inorganic filler takes a great part in enhancing the impact resistance of PLA composites. Such analogous effects of BaSO 4 on thermoplastic polymers have also been approved by other researchers, and the significant improvement on impact toughness should be ascribed to the fine particle size as well as homogeneous dispersity of BaSO 4 in the PLA matrix . Our previous study has demonstrated that samples with added precipitated BaSO 4 are accompanied by the increased average diameter and worsened dispersion of inorganic fillers in the polymer matrix .…”

Preparation and characterization of polyoxymethylene nanocomposites

“…Although the thermal stability of POM matrix was lowered, better friction reduction and wear resistance, especially under high load, were observed (Wang et al, 2008). In another work, spherical nanoparticles of barium sulfate (BaSO 4 ) were introduced into the POM matrix and the radio-opacity to X-ray tests revealed an increase in the optical contrast as the BaSO 4 concentration increased, allowing the control of the optical density, which is important from a biomedical point of view (Romero-Ibarra et al, 2012). The results of tribological tests showed that the POM with MoS 2 nanoballs displayed better tribological properties than they did with micro-MoS 2 .…”

Synthesis and Characterization of Novel Radiopaque Polycarbonate

“…It is easy to cause incompatibility between the heavy metal salt and the polymer, which seriously affects the mechanical strength and fracture toughness of the polymer system. [6] On the other hand, the unstable bond between the heavy metal salt and the polymer easily causes the heavy metal salt to precipitate in the later stage of implantation in the human body, and the precipitated heavy metal salt might be toxic to the human body. [7] The chemical modification method refers to the introduction of iodine atoms or other heavy atoms into the polymer through a chemical reaction in a covalent manner, and the heavy atoms are not easily removed from the polymer, so that the X-ray opaque polymers have better biocompatibility.…”