Use of synthetic wollastonite nanofibers in enhancing mechanical, thermal, and flammability properties of polyoxymethylene nanocomposites

Abstract

This study investigates the mechanical, thermal, and flammability properties of synthetic wollastonite nanofibers (SWN) reinforced polyoxymethylene (POM) nanocomposites. SWN has been added into the POM nanocomposites in the range of 0.5-3 phr via melt blending. The mechanical properties were investigated through tensile and impact tests with scanning electron microscopy and energy dispersive X-ray analysis. The thermal characterization was performed by thermogravimetry analysis and differential scanning calorimetry. Flame retardancy of nanocomposites was studied through cone calorimetry analysis and limiting oxygen index test. The tensile strength of nanocomposites improved by 5.88% at 1 phr SWN content, whereas Young's modulus increased with increasing content. The thermal stability of nanocomposites was enhanced as indicated by the higher initial degradation temperature, which rose about 22 C at 1 phr SWN content. The POM/SWN nanocomposites exhibited better mechanical strength despite their lower crystallinity due to the substantial reinforcing effect of SWN. The flame retardancy of nanocomposites improved, as indicated by the reduction of peak heat release rate from the cone calorimetry test. This study shows that SWN has simultaneously enhanced the mechanical strength, thermal stability, and flame retardancy of POM nanocomposites and has the potential in automotive applications.flame retardancy, mechanical properties, nanocomposites, polyoxymethylene, thermal properties, wollastonite | INTRODUCTIONPolyoxymethylene (POM) also known as polyacetal, is a widely used engineering thermoplastics with high commercial value. [1][2][3] POM comprises formaldehyde ( CH 2 O ) repeating units without bulky side groups, which gives high crystallinity due to its high flexibility and mobility. The high crystallinity of POM contributes to the high mechanical strength, stiffness, and dimensional stability, making it capable of being an alternative to metallic materials for a wide range of applications, such as automotive, electrical, and electronic, precise machinery, construction, and household appliances. [4][5][6][7] However, POM does have limitations on the thermal

Effect of aspect ratio of synthetic Wollastonite nanofibers on mechanical, thermal and flammability properties of polyoxymethylene nanocomposites

“…As previously reported in our study, it was anticipated that SWN did not perform as a nucleating agent for POM nanocomposites, which is in line with our expectations. 30 Furthermore, the aspect ratio of SWN did not significantly affect the X c of POM nanocomposites based on the result tabulated in Table 3. It is suggested that the decrement in the X c of POM nanocomposites caused by the incorporation of SWN 30 has overshadowed the effect of the SWN aspect ratio.…”

“…Then, SWN was incorporated into the POM matrix with the optimum filler content of 1 phr that provided the best-balanced properties of POM/SWN nanocomposites. 30 POM/SWN nanocomposites were prepared by a two-stage melt blending for better filler dispersion in the POM. During the melt blending, a single screw extruder (model: HAAKE Poly-Lab OS) was used with a barrel temperature of 190 C and screw rotation of 60 rpm.…”

“…Recently, synthetic wollastonite nanofiber (SWN) has been reported in producing polyoxymethylene (POM) 30 and PBT 31 nanocomposites. POM is a widely used engineering thermoplastic with great mechanical strength but satisfactory thermal stability and poor performance on flame retardancy 32 .…”

“…Wollastonite can be synthesized in nanosized via hydrothermal or sol-gel reactions, 26 but there are only a limited number of studies that have investigated the use of synthetic nano-sized wollastonite as a means of enhancing the properties of polymer nanocomposites. [27][28][29] Recently, synthetic wollastonite nanofiber (SWN) has been reported in producing polyoxymethylene (POM) 30 and PBT 31 nanocomposites. POM is a widely used engineering thermoplastic with great mechanical strength but satisfactory thermal stability and poor performance on flame retardancy.…”

Mechanical, thermal, tribological, and flammability properties of polybutylene terephthalate composites: Comparing the effects of synthetic wollastonite nanofibers, natural wollastonite, and graphene oxide

“…With the recent focus on nanotechnologies, nanoscale wollastonite has been incorporated into polymers to form polymer nanocomposites with enhanced functional properties. [17][18][19] Nano-scale wollastonite with tunable shapes and sizes can be obtained through chemical routes. 20 Luyt and coworkers synthesized wollastonite nanoparticles through a sol-gel reaction route.…”