Wollastonite is a functional filler that has great potential to be used in thermoplastic composites, replacing more expensive reinforcement such as glass fiber. Wollastonite-reinforced polymer composite materials have attracted the attentions from research field and industries due to their biocompatibility and reinforcing ability in polymers. Due to the relatively high aspect ratio and hardness, wollastonite is able to improve the tensile and flexural strength of polymer composites. Many researches have been conducted to determine various properties of wollastonite reinforced polymer composites such as mechanical, flammability, thermal, and tribological properties in order to explore their potential in various applications. This review will focus on mechanical properties of wollastonite reinforced thermoplastic composites. Overall, it can be concluded that the properties of wollastonite-filled polymer composites are the function of filler content, adhesion interactions of wollastonite particles with polymer matrix, size and shape of wollastonite particles.Further research and development are needed to widen its application, and these include the use of nano-size wollastonite which can be produced synthetically as functional filler in thermoplastics.
K E Y W O R D Scomposites, mechanical properties, thermoplastic, wollastonite
Polymer nanocomposites with enhanced performances are becoming a trend in the current research field, overcoming the limitations of bulk polymer and meeting the demands of market and society in tribological applications. Polytetrafluoroethylene, poly(ether ether ketone) and ultrahigh molecular weight polyethylene are the most popular polymers in recent research on tribology. Current work comprehensively reviews recent advancements of polymer nanocomposites in tribology. The influence of different types of nanofiller, such as carbon-based nanofiller, silicon-based nanofiller, metal oxide nanofiller and hybrid nanofiller, on the tribological performance of thermoplastic and thermoset nanocomposites is discussed. Since the tribological properties of polymer nanocomposites are not intrinsic but are dependent on sliding conditions, direct comparison between different types of nanofiller or the same nanofiller of different morphologies and structures is not feasible. Friction and wear rate are normalized to indicate relative improvement by different fillers. Emphasis is given to the effect of nanofiller content and surface modification of nanofillers on friction, wear resistance, wear mechanism and transfer film formation of its nanocomposites. Limitations from the previous works are addressed and future research on tribology of polymer nanocomposites is proposed.
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
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