Effect of hybrid wollastonite with different nucleation and morphology on the crystallization and mechanical properties of polypropylene

Abstract

In order to prepare polypropylene (PP) composites with balanceable stiffness and toughness, hybrid wollastonite with different nucleation and morphology as fillers were added into PP matrix. Nucleation efficiency (NE), crystallization behavior and melting characteristics, as well as the mechanical properties of hybrid wollastonite-filled PP composites were systematically investigated using differential scanning calorimetry, wide-angle X-ray diffraction, mechanical testing, and scanning electron microscopy, respectively. The results indicated that the NE of wollastonite with b-nucleation is much higher than that of acicular wollastonite and ultrafine wollastonite with a-nucleation, and eventually hybrid wollastonite-filled PP composites mainly form b-phase PP. Furthermore, there exists cooperative effect between the reinforcement of wollastonite of different morphology and the toughening of b-phase, which can be effectively controlled through regulating the nucleating ability, morphology, and mass ration of hybrid wollastonite. POLYM. COMPOS., 00:000-000, 2018.that the addition of AW and BW is able to enhance the stiffness of PP, and the b-phase induced by b-W can significantly improve the toughness of PP. It should be noted that the synergistic effect between b-W and AW is more effective for the improvement of impact strength of PP, while the synergistic effect between b-W and BW is better for the enhancement of PP stiffness. CONCLUSIONSAcicular wollastonite and ultrafine wollastonite present different degree of a-nucleation for the crystallization of FIG. 12. SEM images of B 0 (a), B 3 (b) and B 5 (c). FIG. 11. Impact strength of b-W/BW hybrid-filled PP composites. 8 POLYMER COMPOSITES-2018

Synchronously Strengthen and Toughen Polypropylene Using Tartaric Acid-Modified Nano-CaCO3

“…In order to confirm that β-PP was not formed in CC/PP and TAMCC/PP, the XRD patterns of neat PP, CC/PP, and TAMCC/PP were measured (Figure 5b). There were five peaks at 2θ = 14.5 040), ( 130), (111), and (131) planes of α-PP, respectively [8,36,38]. It could be found that both XRD patterns of CC/PP and TAMCC/PP were similar with that of neat PP without showing the representative peaks of β-PP, further verifying that both CC and TAMCC could not toughen PP by the formation of β-PP as described above.…”

“…In turn, better mobility would also promote the dispersion of nanofillers, i.e., TAMCC. Furthermore, it could be also found that all of the DSC melting curves of neat PP, CC/PP, and TAMCC/PP manifested only a single melting peak at the temperature higher than 160 • C, which was the representative melting peak of α-PP, suggesting that the addition of CC or TAMCC could not result in the formation of any other crystal types in PP [31,35,36]. As is well known, PP can be categorized into three classes based on the crystal form, i.e., the monoclinic, trigonal, and orthorhombic types, corresponding to α-, β-, and γ-PP, respectively.…”

“…the XRD patterns of neat PP, CC/PP, and TAMCC/PP were measured (Figure 5b). There were five peaks at 2θ = 14.5°, 17.2°, 18.8°, 21.2°, and 22.1° in the XRD pattern of neat PP, corresponding to (110), ( 040), ( 130), (111), and (131) planes of α-PP, respectively [8,36,38].…”

Mechanical properties of wollastonite reinforced thermoplastic composites: A review

“…New PP composites were developed by hybridizing wollastonite with different nucleation and morphology namely acicular wollastonite (AW), ultrafine wollastonite (BW) and W x , shown in Figure . The results showed that W x /AW and W x /BW fillers increased the tensile and flexural modulus of PP composites.…”

“…The reinforcing wollastonite and toughening of β‐crystal synergistically improved the mechanical properties of W x reinforced PP. Similarly, the impact strength improvements by W x /AW and W x /BW fillers were attributed to the induction of β‐phase by W x . Results obtained in work of Meng and Dou revealed that untreated wollastonite decreased the impact strength but various loadings of W x improved the impact strength of PP/wollastonite composites .…”