Crystalline morphology and mechanical properties of isotactic polypropylene composites filled by wollastonite with β-nucleating surface

Abstract

Wollastonite-filled a-isotactic polypropylene (iPP) and b-iPP were prepared through introduction of wollastonite (W) and wollastonite with b-nucleating surface (W x ) in iPP matrix. The a-and b-nucleating ability of wollastonite, crystalline morphology, and mechanical properties of injected iPP filled by wollastonite with different nucleating surface were compared using differential scanning calorimetry, wide-angle X-ray diffraction, polarizing optical microscopy, mechanical testing, and scanning electron microscopy. The results indicated that iPP filled by wollastonite with different nucleating surface has different crystalline morphology, melting behavior, and mechanical properties. The W and W x filled iPP mainly formed a-and b-phase iPP, respectively. The tensile and flexural modulus of iPP/W and iPP/W x increased with increasing wollastonite content, and the tensile and flexural modulus of iPP/W x were lower than that of iPP/W. The tensile property, flexural property, and impact strength of iPP/W x were higher than that of iPP/W and b-iPP. The synergistic effect of reinforcing of wollastonite and toughening of b-phase leads to higher mechanical properties. POLYM. COMPOS.,

Mechanical properties of wollastonite reinforced thermoplastic composites: A review

“…α‐nucleating surface wollastonite and W x influenced the impact strength of PP composites differently . Both fillers increased the impact strength with increasing wollastonite content until maxima 5 wt% then decreased.…”

“…Many aspects of mechanical properties of wollastonite reinforced PP composites were studied, such as effects of different loadings, surface treatments, shapes, and sizes of wollastonite. In general, the incorporation of wollastonite have shown to reduce the tensile strength and elongation at break of the PP composites, but improved the tensile modulus, flexural strength, and flexural modulus . The reduction of elongation at break is due to the movement restriction of polymer chains by wollastonite while the deterioration of tensile strength is mainly due to the poor interfacial adhesion between wollastonite and PP.…”

“…The poor adhesion causes ineffective stress transfer from polymer to wollastonite and even causes microfracture in the composite. In most cases, when interfacial interaction is improved by coating wollastonite with surface modifier, which can interact with wollastonite and polymer matrix in the same time, tensile strength of PP composites will be enhanced with a concomitant decrease in elongation at break …”

“…Study on the effect of α‐ and β‐nucleating surface wollastonite was conducted . α‐phase iPP formed when wollastonite reinforced iPP matrix, while β‐phase iPP formed when pimelic acid treated wollastonite (W x ) was introduced.…”

Filling and coloring effect of pearl shell powder and dye‐loaded pearl shell powder on polypropylene

“…It has been reported that the presence of β-phase in PP led to the better mechanical properties, particularly the impact strength. 14,45,46 Thus, the superior impact strength of the DPSP/PP composites to that of PSP/PP was partially due to their higher β-phase content.…”