Effect of composition and component structure on thermal behavior and miscibility of polypropylene catalloys

Shangguan, Yonggang; Tao, Liyang; Zheng, Qiang

doi:10.1002/app.26501

Cited by 9 publications

(8 citation statements)

References 27 publications

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“…Figure 1(a) gives the reversible heat flow of IPC sample. It can be found that there appear two T g s. The higher T g should be attributed to the propylene homopolymer, and the other, to EPR, according to the previous reports 17–19. Even it has been reported that IPC contains ethylene‐propylene block copolymer as a third component,19 the T g of this block copolymer is difficult to be determined.…”

Section: Resultsmentioning

confidence: 88%

“…It can be found that there appear two T g s. The higher T g should be attributed to the propylene homopolymer, and the other, to EPR, according to the previous reports 17–19. Even it has been reported that IPC contains ethylene‐propylene block copolymer as a third component,19 the T g of this block copolymer is difficult to be determined. The reasons for these results are involved in two factors: one is that the T g of the block copolymer is the same with that of the EPR or propylene homopolymer, hence the transition of the block copolymer is covered by that of other components; the other is that the content of the block copolymer in IPC is too low.…”

Section: Resultsmentioning

confidence: 88%

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Study on thermal behavior of impact polypropylene copolymer and its fractions

Zhang

Shangguan

Chen

et al. 2010

J of Applied Polymer Sci

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An impact polypropylene copolymer (IPC) was fractionated into three fractions using n‐octane as solvent by means of temperature‐gradient extraction fractionation. The glass transitions, melting, and crystallization behavior of these three fractions were studied by modulated differential scanning calorimeter (MDSC) and wide‐angle X‐ray diffraction (WAXD). In addition, successive self‐nucleation and annealing (SSA) technique was adopted to further examine the heterogeneity and the structure of its fractions. The results reveal that the 50°C fraction (F50) mainly consists of ethylene‐propylene random copolymer and the molecular chains may contain a few of short but crystallizable propylene and/or ethylene unit sequences; moreover, the lamellae thicknesses of the resulting crystals are extremely low. Furthermore, 100°C fraction (F100) mainly consist of some branched polyethylene and various ethylene‐propylene block copolymers in which some ethylene and propylene units also randomly arrange in certain segments, and some polypropylene segments can form crystals with various lamellae thickness. An obvious thermal fractionation effect for F100 samples after being treated by SSA process is ascribed to the irregular and nonuniform arrangement of ethylene and propylene segments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 88%

Study on thermal behavior of impact polypropylene copolymer and its fractions

Zhang

Shangguan

Chen

et al. 2010

J of Applied Polymer Sci

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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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“…6 –9 Over the last decades, copolymerization has been realized as effective approaches to improve physical and mechanical properties of polymeric materials. 10,11…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8][9] Over the last decades, copolymerization has been realized as effective approaches to improve physical and mechanical properties of polymeric materials. 10,11 Block copolymers can form meso structures at the nanometer-length scale, which has been the subject of intense research for the past four decades. Recently, constructing block copolymers with hierarchical structures has been the new focus of research.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and thermal decomposition kinetics of poly(methyl methacrylate)-b-poly(styrene) block copolymers

Guan

Hua-long

et al. 2015

Journal of Thermoplastic Composite Materials

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Two diblock copolymers of poly(methyl methacrylate)- block-poly(styrene) with chlorine as terminal group (PMMA- b-PS-Cl) were synthesized via two-step atom transfer radical polymerization. The structures of the block copolymers were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and gel permeation chromatography. Thermal properties including glass transition temperature ( Tg) and thermal stability were studied by differential scanning calorimetry and thermogravimetric analysis (TGA), respectively. The block copolymers of PMMA- b-PS-Cl exhibited two glass transitions, which were attributed to the Tgs of PMMA and PS segments, respectively. According to TGA, thermal decompositions of PMMA macro-initiator and PMMA- b-PS-Cl block copolymers had two stages. The weight loss ratio in the second stage was more significant than that in the first stage, which may be attributed to the separation of the halogen atom from the terminal group and the formation of a double bond. The breaking down of the backbone dominates in the second stage in which the weight loss ratio was more than 70%, represented the main stage of pyrolysis. It was found that the introduction of the PS chain remarkably enhanced the thermal stability of the copolymer, thus endowing the block copolymers high activation energy for thermal decomposition. On the other hand, the remaining two pyrolysis procedures further indicated that thermodynamic mechanism didn’t change due to the introduction of PS segments.

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Effect of composition and component structure on thermal behavior and miscibility of polypropylene catalloys

Cited by 9 publications

References 27 publications

Study on thermal behavior of impact polypropylene copolymer and its fractions

Study on thermal behavior of impact polypropylene copolymer and its fractions

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

Synthesis and thermal decomposition kinetics of poly(methyl methacrylate)-b-poly(styrene) block copolymers

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