?- and ?-crystalline forms of isotactic polypropylene investigated by nanoindentation

Labour, Thomas; Ferry, Laurent; Gauthier, Catherine; Hajji, Philippe; Vigier, G.

doi:10.1002/(sici)1097-4628(19991003)74:1<195::aid-app24>3.0.co;2-8

Cited by 36 publications

(21 citation statements)

References 16 publications

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“…In a previous work by Chan et al,14 the differential scanning calorimetry results indicated the presence of a small amount of β‐phase PP, after the addition of CaCO 3 nanoparticles. Labour et al22 found that, since the β‐phase has less crystal density than that of the α phase, the β‐phase PP exhibits a lower modulus by about 10% and a reduced hardness by 15%, respectively, than the α‐phase PP. The presence of the β‐phase crystal around the CaCO 3 particles in PP may greatly affect the operative toughening mechanisms in the PP/CaCO 3 nanocomposite, as well.…”

Section: Resultsmentioning

confidence: 99%

Impact‐toughening mechanisms of calcium carbonate‐reinforced polypropylene nanocomposite

Weon

Gam

Boo

et al. 2006

J of Applied Polymer Sci

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ABSTRACT:The impact fracture mechanisms of polypropylene (PP), containing 9.2 vol % of calcium carbonate (CaCO 3 ) nanoparticles, were investigated using optical microscopy and transmission electron microscopy. The incorporation of CaCO 3 nanoparticles reduces the size of spherulites and induces the formation of ␤-phase crystallites, which leads to a more ductile PP matrix. Double-notch four-point bending (DN-4PB) Charpy impact specimens and notched Izod impact specimens were utilized to study the fracture mechanism(s) responsible for the observed toughening effect. A detailed investigation reveals that the CaCO 3 nanoparticles act as stress concentrators to initiate massive crazes, followed by shear banding in PP matrix. These toughening mechanisms are responsible for the observed, improved impact strength. A comparison of the fracture mechanisms observed between DN-4PB Charpy and Izod impact tests is also made to show the effectiveness of DN-4PB for investigation of impact fracture mechanisms of polymeric systems.

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Section: Resultsmentioning

confidence: 99%

Impact‐toughening mechanisms of calcium carbonate‐reinforced polypropylene nanocomposite

Weon

Gam

Boo

et al. 2006

J of Applied Polymer Sci

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“…Concerning the effect of thermal treatment, Maiti P et al22 reported that annealing at a high temperature subsequent to a lower temperature crystallization promotes much more rapid lamellar thickening than crystallization alone does at the same high temperature. It is concluded that the relative amount of β‐crystal within PP crystals increases at an annealing in the interval of temperatures from 110 to 140 °C, which enhanced ductility of PP and improved its impact properties 23–26. However, according to refs.…”

Section: Introductionmentioning

confidence: 94%

Effects of filler size and heat treatment on the crystallization behavior of glass bead‐filled polypropylene

Yuan¹,

Jiang²,

An³

et al. 2004

J Polym Sci B Polym Phys

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The effects of glass bead (GB) size and annealing temperature on the formation of β‐crystals of glass bead‐filled polypropylene (PP) are studied in this articles. Differential scanning calorimetry (DSC) measurements indicated that the amount of β‐form in PP crystals was a function of the glass bead content and size. For a fixed glass bead content, it was found that the smaller the diameter of the glass bead, the higher was the content of β‐crystals formed in the PP. On the other hand, wide‐angle X‐ray diffraction (WAXD) measurements revealed that the annealing temperature was also a major factor that affected the crystallization behavior of glass bead‐filled PP. It seemed that the blends with different glass bead contents had their own optimal annealing temperatures for β‐crystal formation. As an example, when the glass bead content was 48 wt %, the optimal annealing temperature for β‐crystal formation was about 108 °C, whereas it shifted to 100 °C for 14 wt % glass bead‐filled polypropylene. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 306–313, 2005

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“…[36][37][38][39][40][41] The elastic modulus determined by AFM nanoindentation of iPP grown from the surface of carbon fibers has a value of 1.6-3 times higher in the direction perpendicular to the crystalline growth compared to that in the direction of the growth. 23 Nanoindentation was used to compare a2 and b-type spherulites 42 and it was concluded that the b-spherulites have elastic modulus and hardness values 10 and 15% lower than the a-spherulites, respectively. Studies of the effect of cooling rate on the elastic modulus of melt solidified samples measured using AFM indentation led to the conclusion that the hardness and modulus decrease as the cooling rate increases.…”

Section: Introductionmentioning

confidence: 99%

Elastic constants of lamellar and interlamellar regions in α and mesomorphic isotactic polypropylene by AFM indentation

Picu

Osta

2016

J of Applied Polymer Sci

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A study of the nanoscale mechanical properties of isotactic mesomorphic and semi‐crystalline polypropylene (iPP) is presented. Two iPPs produced with metallocene and Ziegler‐Natta catalyst polymerization are used. The resulting fibers are characterized by wide angle X‐ray scattering, small‐angle X‐ray scattering (SAXS), and Raman spectroscopy. The spatial variability of the percentage crystallinity is evaluated based on the SAXS data. AFM indentation is performed to measure the elastic modulus of the fibers in the direction perpendicular and parallel to the fiber axis. Since the AFM probing is performed on a scale larger than the lamellar thickness, a statistical analysis of the AFM and SAXS data is necessary to infer the elastic moduli of the α crystals and of the inter‐lamellar regions. The elastic modulus of the crystalline lamellae in the direction perpendicular to the c‐axis of the α crystal probed in compression is estimated at approximately 3.3 GPa, while the effective modulus of the interlamellar regions ranges from 1.5 to 2.2 GPa. The method proposed can be applied to other material systems with similar layered structure to measure elastic moduli or hardness on length scales smaller than the resolution of the indentation test. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43649.

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?- and ?-crystalline forms of isotactic polypropylene investigated by nanoindentation

Cited by 36 publications

References 16 publications

Impact‐toughening mechanisms of calcium carbonate‐reinforced polypropylene nanocomposite

Impact‐toughening mechanisms of calcium carbonate‐reinforced polypropylene nanocomposite

Effects of filler size and heat treatment on the crystallization behavior of glass bead‐filled polypropylene

Elastic constants of lamellar and interlamellar regions in α and mesomorphic isotactic polypropylene by AFM indentation

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