Polymerization control and fast characterization of the stereo-defect distribution of heterogeneous Ziegler–Natta isotactic polypropylene

Kang, Jian; Yang, Feng; Wu, Tong; Li, Huilin; Cao, Ya; Xiang, Ming

doi:10.1016/j.eurpolymj.2011.11.023

Cited by 72 publications

(57 citation statements)

References 61 publications

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“…Consequently, several attempts were made to calculate chain regularity from melting traces recorded after SSA crystallization, since the traces recorded after SIST and SSA crystallization, respectively, are similar [16,17]. Although, differences in the chain structure of the polymer were revealed clearly in these studies, the chain regularity estimated is questionable because of the short step time (t a = 15 min) used.…”

Section: The Concept Of the Sist Techniquementioning

confidence: 99%

“…Although, differences in the chain structure of the polymer were revealed clearly in these studies, the chain regularity estimated is questionable because of the short step time (t a = 15 min) used. The short t a used by Chang et al [16] and Kang et al [17] was proposed earlier by Lorenzo et al [18], but the latter article focused on the kinetics of self-nucleation and chain regularity was not calculated in that work. Accordingly, our goal was to investigate the effect of experimental conditions and evaluation technique on the results of thermal fractionation experiments, with special focus on the estimation of average chain regularity (I av ) from melting traces recorded after fractionated crystallization.…”

Section: The Concept Of the Sist Techniquementioning

confidence: 99%

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Chain regularity of isotactic polypropylene determined by different thermal fractionation methods

Horváth

Menyhárd

Doshev

et al. 2014

J Therm Anal Calorim

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The chain regularity of isotactic polypropylene (iPP) homo-and random copolymers was characterized by different thermal fractionation methods in this study. Different stepwise temperature programs were applied in a calorimeter (DSC), in order to develop a method which is significantly faster than SIST and provides reliable information about the chain regularity of iPP. Our studies prove that self-seeding accelerates the crystallization process during annealing in SSA-DSC experiments (successive self-nucleation and annealing). Consequently, the time of isothermal steps can be shortened significantly in the SSA-DSC method. On the other hand we found that step time should not be too short if the goal of the measurement is the determination of average chain regularity. Our results clearly indicate that both the experimental conditions and the evaluation technique influence the obtained results. A standard experimental procedure is proposed for reliably determining the average chain regularity of iPP. The length of the SSA-DSC temperature program developed in this study is much shorter compared to that of the conventional SIST (stepwise isothermal segregation technique) measurements used recently for such experiments. The proposed SSA-DSC program makes the reliable characterization of a large number of samples on an acceptable timescale possible.

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Section: The Concept Of the Sist Techniquementioning

confidence: 99%

Section: The Concept Of the Sist Techniquementioning

confidence: 99%

Chain regularity of isotactic polypropylene determined by different thermal fractionation methods

Horváth

Menyhárd

Doshev

et al. 2014

J Therm Anal Calorim

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show abstract

“…SSA fractionation is an effective way to analysis the microstructure and crystallization behavior of poly mers [28,29], which is applied in this study to provide deep understanding on the crystallization behavior of the PVDF/PVP blends. The SSA final melting curves of the samples are shown in Fig.…”

Section: Successive Self Nucleation and Annealing (Ssa)mentioning

confidence: 99%

Crystallization behavior, tensile behavior and hydrophilicity of poly(vinylidene fluoride)/poly(vinyl pyrrolidone) blends

et al. 2014

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Binary polymer blends of hydrophobic poly(vinylidene fluoride) (PVDF) and hydrophilic poly(vinylpyrrolidone) (PVP) were prepared by melt blending.The crystallization behavior, mechanical properties and hydrophilicity of the binary blends were investigated using Fourier transform infrared spec troscopy (FTIR), wide angle X ray diffractometry (WAXD), differential scanning calorimeter (DSC) scan ning, non isothermal crystallization kinetics, successive self nucleation and annealing (SSA) fractionation, tensile tests and contact angle tests. The analysis of FTIR, WAXD, DSC scanning, non isothermal crystalli zation kinetics and SSA fractionation showed that the addition of PVP greatly influenced the crystallization behavior of the sample. As the PVP content increased, the crystallization temperature, crystallization rate, degree of crystallinity, and the amount of thick lamellaes decreased gradually. Meanwhile, PVP favored the formation of β phase of PVDF. The results of tensile test revealed that the addition of PVP increased the elon gation at break of the sample, and lowered the yield stress. Besides, the result of contact angle test indicated that the hydrophilicity of PVDF was remarkably improved in the presence PVP. The relationship between crystallization behavior and the tensile behavior, hydrophilicity were discussed.

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“…The temperature scale calibration was performed using indium as a standard to ensure reliability of the data obtained [51][52][53][54]. 5 mg round samples were used.…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

Influence of melt structure on the crystallization behavior and polymorphic composition of polypropylene random copolymer

et al. 2015

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Polymerization control and fast characterization of the stereo-defect distribution of heterogeneous Ziegler–Natta isotactic polypropylene

Cited by 72 publications

References 61 publications

Chain regularity of isotactic polypropylene determined by different thermal fractionation methods

Chain regularity of isotactic polypropylene determined by different thermal fractionation methods

Crystallization behavior, tensile behavior and hydrophilicity of poly(vinylidene fluoride)/poly(vinyl pyrrolidone) blends

Influence of melt structure on the crystallization behavior and polymorphic composition of polypropylene random copolymer

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