Influence of nucleation on the brittle‐ductile transition temperature of impact‐resistant polypropylene copolymer: From the sight of phase morphology

Dong, C.; Feng, Jiachun; Yi, Jianjun

doi:10.1002/app.34639

Cited by 13 publications

(15 citation statements)

References 44 publications

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“…This is possibly because the crystallization rate is faster in the presence of β‐NA and there is no enough time for the exclusion of the amorphous component outside the crystallites. Similar result was also reported by Feng and coworkers . It should be noted that, the amorphous components in polymers of low crystallinity, such as IPCs, can be located both outside the macroscopic crystals and among the inter‐lamellae .…”

Section: Resultssupporting

confidence: 88%

A highly efficient β‐nucleating agent for impact‐resistant polypropylene copolymer

Liu

Tong

et al. 2014

J of Applied Polymer Sci

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In this work, we reported calcium tetrahydrophthalate as a high efficient b-nucleating agent (b-NA) for impact-resistant polypropylene copolymer (IPC). The relative fraction of the b-crystal can reach as high as 93.5% when only 0.03% b-NA is added. The non-isothermal and isothermal crystallization behaviors, morphology, lamellar structure and mechanical properties of IPCs with various b-NA contents were studied. During non-isothermal crystallization, the cooling rate has an important influence on the relative fraction of the b-crystal, which decreases remarkably as the cooling rate increases. The b-NA also greatly accelerates crystallization rate of IPC, resulting from both more crystal nuclei and larger Avrami exponent. The small angle X-ray scattering characterization shows that more amorphous components are included into the inter-lamellae after addition of b-NA. Dynamical mechanical analysis (DMA) reveals that the storage modulus at low temperature and the loss factor above 0 C from the PP component can be enhanced upon addition of b-NA and reach a maximum at the b-NA content of 0.05 wt %. Impact test shows that the impact strength of the IPC at 0 C can be improved as much as 40% when the content of calcium tetrahydrophthalate is 0.10 wt %. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40753.

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Section: Resultssupporting

confidence: 88%

A highly efficient β‐nucleating agent for impact‐resistant polypropylene copolymer

Liu

Tong

et al. 2014

J of Applied Polymer Sci

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“…where H m is the value of fusion enthalpy of the sample obtained during the DSC heating scan, 0 m H  is the fusion enthalpy of the completely crystalline iPP, and  is the relative fraction (77 wt%) of iPP in the IPC [34] .…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

Annealing induced microstructure and mechanical property changes of impact resistant polypropylene copolymer

et al. 2015

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The effects of annealing on microstructure and mechanical properties of an impact resistant polypropylene copolymer (IPC) were investigated. Different annealing temperatures ranging from 80 °C to 160 °C were selected. The phase reorganization of IPC during annealing process was studied through morphological characterization technologies, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystalline structure changes in the IPC sample, including the iPP matrix and PE component, were investigated using wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). Dynamic mechanical analysis (DMA) was used to analyze the relaxation extent of IPC before and after annealing. The results showed that annealing induced phase reorganization in IPC and the degree of phase reorganization depended on annealing temperature. The annealed IPC samples exhibited largely increased crystallinity compared with the unannealed one. Intensified damping peak with increased molecular chain mobility was achieved for the annealed IPC samples. At an appropriate annealing temperature (140 °C), largely enhanced impact strength was achieved for the annealed IPC sample. The toughening mechanisms were analyzed based on the phase reorganization and relaxation behavior.

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“…Since the discovery of Catalloy process by Himont company, polypropylene (PP) in‐reactor alloy has attracted many researchers because of its good balance in tensile strength and impact strength 1, 2. To further optimize the properties of PP in‐reactor alloys, lots of studies have been devoted to the polymerization process, chain structure, crystallization behavior, and phase morphology of PP in‐reactor alloys 3–28. A two‐stage polymerization process (TSP) is commonly used to produce polypropylene/ethylene‐propylene random copolymer (PP/EPR) in‐reactor alloys: propylene homopolymerization followed by ethylene‐propylene copolymerization 29–32.…”

Section: Introductionmentioning

confidence: 99%

Effect of phase separation on overall isothermal crystallization kinetics of PP/EPR in‐reactor alloys

Liu

et al. 2012

J of Applied Polymer Sci

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In the present work, the effect of phase separation on overall isothermal crystallization kinetics of two polypropylene/ethylene-propylene random copolymer (PP/EPR) in-reactor alloys was investigated. It is found that at lower crystallization temperatures (T c ), the overall crystallization rate decreases with increasing phase separation temperature (T s ). This is attributed to the lower linear spherulitic growth rate incurred by the lower PP content in the PP-rich phase at higher T s s. In contrast, at higher T c s, quenching from a higher T s to T c promotes nucleation as a result of more dramatic concentration fluctuation, leading to a faster overall crystallization rate. The overall crystallization rate of the PP/EPR in-reactor alloy prepared by multi-stage sequential polymerization process (MSSP) is retarded by increasing phase separation time (t s ). However, prolonging phase separation time has little effect on the crystallization rate of the sample prepared by two-stage polymerization process (TSP). This result can be attributed to the different phase separation rates of these two samples. The SAXS result confirms that at higher T c , phase separation in the melt before crystallization can retard crystallization, when compared with the directly quenched samples. It is also found that the phase-separated PP/EPR in-reactor alloys exhibit a larger long period because of more amorphous phases included between the lamellar crystals.

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Influence of nucleation on the brittle‐ductile transition temperature of impact‐resistant polypropylene copolymer: From the sight of phase morphology

Cited by 13 publications

References 44 publications

A highly efficient β‐nucleating agent for impact‐resistant polypropylene copolymer

A highly efficient β‐nucleating agent for impact‐resistant polypropylene copolymer

Annealing induced microstructure and mechanical property changes of impact resistant polypropylene copolymer

Effect of phase separation on overall isothermal crystallization kinetics of PP/EPR in‐reactor alloys

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