Investigation of the stereodefect distribution and conformational behavior of isotactic polypropylene polymerized with different Ziegler–Natta catalysts

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

doi:10.1002/app.36357

Cited by 42 publications

(46 citation statements)

References 45 publications

(46 reference statements)

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“…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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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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“…To eliminate the disturbing effect of β-α recrystallization, T end = 100°C is selected after the sample is cooled at different cooling rates (2,5,10,20 and 40°C/min). The obtained melting curves at the heating rate of 10°C/min are shown in Fig.…”

Section: Melting Behaviormentioning

confidence: 99%

Effects of β‐nucleating agent and crystallization conditions on the crystallization behavior and polymorphic composition of isotactic polypropylene/multi‐walled carbon nanotubes composites

Kang

Chen

et al. 2014

Polymers for Advanced Techs

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In this study, the effects of crystallization conditions (cooling rate and end temperature of cooling) on crystallization behavior and polymorphic composition of isotactic polypropylene/multi-walled carbon nanotubes (iPP/MWCNTs) composites nucleated with different concentrations of β-nucleating agent (tradename TMB-5) were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and scanning electronic microscopy (SEM). The results of DSC, WAXD and SEM revealed that the addition of MWCNTs and TMB-5 evidently elevates crystallization temperatures and significantly decreases the crystal sizes of iPP. Because of the competition between α-nucleation (provided by MWCNTs) and β-nucleation (induced by TMB-5), the β-phase crystallization takes place only when 0.15 wt% and higher concentration of TMB-5 is added. Non-isothermal crystallization kinetics study showed that the crystallization activation energy ΔE of β-nucleated iPP/MWCNTs composites is obviously higher than that of pure iPP, which slightly increases with the increase of TMB-5 concentration, accompanying with the transition of its polymorphic crystallization behavior. The results of non-isothermal crystallization and melting behavior suggested that the cooling rate and end temperature of cooling (T end ) are important factors in determining the proportion and thermal stability of β-phase: Lower cooling rate favors the formation of less amount of β-phase with higher thermal stability, while higher cooling rate encourages the formation of higher proportion of β-phase with lower thermal stability. The T end = 100°C can eliminate the β-α recrystallization during the subsequent heating and therefore enhance the thermal stability of the β-phase. By properly selecting TMB-5 concentration, cooling rate and T end , high β-phase proportion of 88.9% of the sample was obtained.

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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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Investigation of the stereodefect distribution and conformational behavior of isotactic polypropylene polymerized with different Ziegler–Natta catalysts

Cited by 42 publications

References 45 publications

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

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

Effects of β‐nucleating agent and crystallization conditions on the crystallization behavior and polymorphic composition of isotactic polypropylene/multi‐walled carbon nanotubes composites

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

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