Influence of molten-state annealing on the phase structure and crystallization behaviour of high impact polypropylene copolymer

Chen, Ruifen; Shangguan, Yonggang; Zhang, Chunhui; Chen, Feng; Harkin‐Jones, Eileen; Zheng, Qiang

doi:10.1016/j.polymer.2011.05.005

Cited by 43 publications

(37 citation statements)

References 30 publications

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“…Obviously, the high the annealing temperature, the more apparent the phase reorganization is. Chen et al [17] reported that in the molten state (200 °C), the phase reorganization of IPC didn't finish even if the annealing time was increased up to 200 min. This indicates that if the solid-state annealing duration is prolonged, the phase reorganization of IPC possibly continues and the real thermodynamic equilibrium state can be achieved.…”

Section: Morphological Changes Of Rubber Particlesmentioning

confidence: 99%

“…Many researches have already proven that the multiphase structure and the final mechanical properties of the IPC articles are greatly dependent upon the thermal history of the sample during processing [13,15,17,18] . For example, Chen et al [17] investigated the phase structure evolution of IPC samples during molten-state annealing, which was carried out at 200 °C.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Chen et al [17] investigated the phase structure evolution of IPC samples during molten-state annealing, which was carried out at 200 °C. They found that the core-shell structure of the dispersed phase was completely destroyed and the sizes of the dispersed domains increased dramatically.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Morphological Changes Of Rubber Particlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2015

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“…[ 2 ] The regular hiPP powder morphology (i.e., regular particle shape, narrow particle size distribution, homogeneous distribution of EPR phase in iPP matrix) contributes to the high reactor throughput and good hiPP powder processability. Many works focus on the morphology of the fi nal hiPP material in the molded or extruded form [3][4][5][6][7] but the characteristic application properties of hiPP are strongly infl uenced directly in the polymerization process. Although a number of papers dealing with the particle morphology after the fi rst (homopolymerization) stage [8][9][10][11] and after the second (copolymerization) stage [11][12][13][14][15][16][17] were published, important questions related to hiPP particle multiphase morphology and its evolution are still open.…”

mentioning

confidence: 99%

Formation and Distribution of Rubbery Phase in High Impact Poly(propylene) Particles

Smolná

Gregor

Buráň

et al. 2016

Macromol. Mater. Eng.

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in inducing crazing and/or shear yield of the isotactic poly(propylene) (iPP) matrix. However, if the dimension of the rubbery domain in the iPP matrix is smaller than the size of the fracture ligament curvature then the rubbery domain is not able to stop the crack propagation. Thus, Jang et al. suggested that the optimal size of EPR domain is 0.5 μm. [ 2 ] The regular hiPP powder morphology (i.e., regular particle shape, narrow particle size distribution, homogeneous distribution of EPR phase in iPP matrix) contributes to the high reactor throughput and good hiPP powder processability. Many works focus on the morphology of the fi nal hiPP material in the molded or extruded form [3][4][5][6][7] but the characteristic application properties of hiPP are strongly infl uenced directly in the polymerization process. Although a number of papers dealing with the particle morphology after the fi rst (homopolymerization) stage [8][9][10][11] and after the second (copolymerization) stage [11][12][13][14][15][16][17] were published, important questions related to hiPP particle multiphase morphology and its evolution are still open. This paper reconstructs the principle of rubber incorporation in high impact poly(propylene) (hiPP) particles. The detailed information about the pores and rubber distribution inside and on the surface of hiPP particles is obtained by micro-computed tomography and atomic force microscopy. The strong effect of homopolymer origin on hiPP particle morphology and rubber distribution is demonstrated. To obtain the most homogeneous rubber distribution, the low homopolymer porosity is required. The initial particle porosity has a negligible effect on the thickness of the rubber layer on the particle surface at the medium rubber content. The rubber forms not only along the iPP primary particles and directly or close to the pores but also on or close to the particle surface rather than it fl ows there. The evidence for these claims is based on the systematic investigation in dependence on EPR content, homopolymer particle porosity (prepared by different catalysts) and antistatic agent deactivating catalyst close to particle surface.

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“…Note that the EPR component in blends was extracted from IPC in n-octane at 50 °C, it could be dissolved completely in xylene at a higher temperature (the n-octane and xylene have similar solubility to EPR [30] ). It has been proved that the great viscosity difference and good compatibility between EPR and EbP component result in the special dispersed phase consisted of EPR and EbP in IPC [5,8] . For the dispersed phase, the core-shell structure is composed of an EbP core (with long ethylene chain segment) and two shells, the outer EbP layer (with long propylene chain segment) and the inner EPR one [5,31,32] .…”

Section: Phase Morphologymentioning

confidence: 99%

Effects of composition on microstructure and crystallization behavior for impact polypropylene copolymer investigated by restructuring the complex core-shell dispersed particles in ternary blends

et al. 2014

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A series of ternary blends of polypropylene/ethylene-propylene random copolymer/ethylene-propylene segmented copolymer (HPP/EPR/EbP) whose microstructures are similar to those of impact polypropylene copolymer (IPC) were prepared in order to systematically investigate the effects of composition on microstructure and crystallization behavior of IPC. The observation of primary phase morphology reveals that the dispersed phase with core-shell structure could be rebuilt in certain composition and excessive EPR leads to a bicontinuous phase structure in ternary blends. After undergoing same quiescent crystallization including isothermal and non-isothermal crystallization, these blend samples exhibit special composition-dependent melting behavior, i.e., the melting point increases markedly with the increase of EPR content until it turns down at a critical content (about 30 wt%). The crystallization behavior is mainly ascribed to the different nucleation abilities. It is suggested that although the compatibility between EPR and HPP components becomes worse with the increase of EPR content due to the increased interfacial area and the decreased concentration of EbP, higher EPR content in the blend facilitates to heterogeneous nucleation except for the appearance of obvious bicontinuous phase structure.

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Influence of molten-state annealing on the phase structure and crystallization behaviour of high impact polypropylene copolymer

Cited by 43 publications

References 30 publications

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

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

Formation and Distribution of Rubbery Phase in High Impact Poly(propylene) Particles

Effects of composition on microstructure and crystallization behavior for impact polypropylene copolymer investigated by restructuring the complex core-shell dispersed particles in ternary blends

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