Investigation on the structure and crystallization behavior of controlled-rheology polypropylene with different stereo-defect distribution

Kang, Jian; Wang, Bin; Peng, Hanyong; Chen, Jinyao; Cao, Ya; Li, Huilin; Yang, Feng; Xiang, Ming

doi:10.1007/s00289-013-1077-y

Cited by 28 publications

(16 citation statements)

References 45 publications

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“…In the previous works, we have synthesized ZN‐iPP resins with similar molecular weight and distribution, nearly same average isotacticity but different uniformities of stereodefect distribution. Their conformational behavior, crystallization behavior, and kinetics had been investigated, and it was found that the uniformity of stereodefect distribution of PP is a determining factor of the crystallization behavior and morphology.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Tensile Behavior and Morphology Evolution of Isotactic Polypropylene Films Polymerized with Different Ziegler-Natta Catalysts

Kang

Xiong

et al. 2015

Adv. Polym. Technol.

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Stereodefect distribution is very important in determining the morphology and properties of isotactic polypropylene (iPP). In this study, two iPPs (PP-A and PP-B) with different uniformities of stereodefect distribution were prepared. The tensile behavior and morphology evolution of their cast films were studied. The morphology study of the cast films showed that compared with PP-B, PP-A with less uniform distribution of stereodefects has smaller spherulites and spheruilitic boundaries and higher degree of crystallinity. In uniaxial tensile measurements, PP-A exhibited higher yield strength and lower elongation at break. When strain was 500%, PP-A exhibits totally transparent appearance and highly oriented structures without cavities, whereas PP-B shows opaque appearance and mass of both nanometer-and micrometer-sized cavities. Moreover, calculation of rigid amorphous fraction (RAF) indicated that PP-B cast film has a higher amount of RAF, which might be the reason for the different morphology evolutions and tensile behaviors of the samples. C 2015 Wiley Periodicals, Inc. Adv Polym Technol 201 , , 21573; View this article online at wileyonlinelibrary.com.

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Section: Introductionmentioning

confidence: 99%

Investigation on the Tensile Behavior and Morphology Evolution of Isotactic Polypropylene Films Polymerized with Different Ziegler-Natta Catalysts

Kang

Xiong

et al. 2015

Adv. Polym. Technol.

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“…From the above, it can be seen that as T f is fixed, the time needed to fulfill the isothermal crystallization increases with an increase of T iso . It can be explained that, according to the crystallization theory, as T iso increases, the crystal growth ability gets improved, while the nucleation rate decreases. The overall crystallization rate is determined by the nucleation rate, resulting in the decrease of the crystallization rate.…”

Section: Resultsmentioning

confidence: 99%

Isothermal crystallization kinetics and subsequent melting behavior of β‐nucleated isotactic polypropylene/graphene oxide composites with different ordered structure

Zeng

Chen

et al. 2018

Polymer International

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The effects of ordered structure on isothermal crystallization kinetics and subsequent melting behavior of -nucleated isotactic polypropylene/graphene oxide (iPP/GO) composites were studied using differential scanning calorimetry. The ordered structure status was controlled by tuning the fusion temperature (T f ). The results showed that depending on the variation of crystallization rate, the whole T f range could be divided into three regions: Region I (T f > 179 ∘ C), Region II (170 ∘ C ≤ T f ≤ 179 ∘ C) and Region III (T f < 170 ∘ C). As T f decreased from Region I to Region III, the crystallization rate would increase substantially at two transition points, due to the variation of the ordered structure status. Calculation of Avrami exponent n indicated that the ordered structure induced the formation of two-dimensional growing crystallites rather than three-dimensional growing crystallites. Moreover, in the case of isothermal crystallization, the ordered structure effect (OSE) can also greatly increase the relative content of -phase ( c ). In Region II, OSE took place, resulting in evident increase of c , achieving 92.4% at maximum. The variation of the isothermal crystallization temperature (T iso ) had little influence on the T f range (Region II) of the OSE. The higher T f in Region II was more favorable for the formation of higher c . The ordered structure was favorable for the improvement of the nucleating efficiency of -nucleating agent ( -NE), and was more effective for the improvement of lower -NE. EXPERIMENTAL MaterialsIsotactic polypropylene resin with trade name of T38F, molecular weight of 347 200 g mol −1 , dispersion index of 3.63, average Polym Int 2018; 67: 1212-1220

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“…Therefore, the influence of ultrasonic irradiation on the conformational and crys tallization behavior of isotactic polypropylene with different stereo defect distribution is still not clear as far as we have concerned. In our previous works [43][44][45][46][47][48][49], using different Ziegler-Natta catalysts with dif ferent polymerization activities, we have synthesized series of isotactic polypropylene with similar molecu lar weights but different uniformities of stereo defect distribution, which provide us precious opportunity to explore the impact of ultrasound on the conformation and crystallization behavior of isotactic polypropylene with different stereo defect distributions.…”

Section: Effects Of Ultrasound On the Conformational And Crystallizatmentioning

confidence: 99%

Effects of ultrasound on the conformational and crystallization behavior of isotactic polypropylene polymerized with different Ziegler—Natta catalyst

Chen

Liu²,

Zeng

et al. 2015

Polym. Sci. Ser. A

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Using different Ziegler-Natta catalysts, we have prepared two samples of isotactic polypropylene with similar molecular weight and average isotacticity, but different stereo defect distributions. The influence of ultrasonic irradiation on the conformation and crystallization behavior of those samples were investigated by differential scanning calorimetry, wide angle X ray diffraction and Fourier transform infrared spectros copy. The ultrasonic treatment induced a decrease in the degree of crystalline perfection and a wider distri bution range of the crystalline perfection of polypropylene. Meanwhile, the crystal particles pack looser and the crystallite size decreased under the influence of ultrasonic irradiation. On the conformation aspect, the molecular movement in polypropylene became more intensive, the molecular entanglement was reduced when ultrasound was applied. Moreover, it was found that the uniformity of stereo defect distribution also played important role in determining the conformation and crystallization behavior of polypropylene sam ples irradiated by ultrasound.

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Investigation on the structure and crystallization behavior of controlled-rheology polypropylene with different stereo-defect distribution

Cited by 28 publications

References 45 publications

Investigation on the Tensile Behavior and Morphology Evolution of Isotactic Polypropylene Films Polymerized with Different Ziegler-Natta Catalysts

Investigation on the Tensile Behavior and Morphology Evolution of Isotactic Polypropylene Films Polymerized with Different Ziegler-Natta Catalysts

Isothermal crystallization kinetics and subsequent melting behavior of β‐nucleated isotactic polypropylene/graphene oxide composites with different ordered structure

Effects of ultrasound on the conformational and crystallization behavior of isotactic polypropylene polymerized with different Ziegler—Natta catalyst

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