Amplified Toughening Effect of Annealing on Isotactic Polypropylene Realized by Introducing Microvoids

Chen, Jingwei; Dai, Jiangdong; Yang, Jing‐hui; Zhang, Nan; Huang, Ting; Wang, Yong; Zhang, Chaoliang

doi:10.1021/ie403872d

Cited by 18 publications

(26 citation statements)

References 39 publications

(80 reference statements)

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“…Enhancing the impact properties of iPP has been successfully fulfilled by introducing rubber phase into iPP matrix . That is due to the fact that the cavitation, shear yielding, and crazing are the main toughening mechanisms in iPP blends . The cavitation could be easily activated in the blended system resulting in toughening material.…”

Section: Application Of Cavities In Semi‐crystalline Polymersmentioning

confidence: 99%

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Men

2018

Macro Materials & Eng

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Cavitation‐induced stress whitening in semi‐crystalline polymers during stretching significantly influences the physical properties of the materials. This review summarizes studies focusing on two different cavitation processes triggered at small and large strain regimes. The corresponding mechanisms of these two cavitation processes are discussed. For cavitation activated at small strain, there are two basic but distinctly different models with the initiation of cavities either in the amorphous phase or in the crystalline skeleton. For the cavitation triggered at a large strain regime, there are also two different arguments being either due to the defects located in the ends of micro‐fibrils or as a consequence of the fragmentation of load‐bearing inter‐fibril/micro‐fibril tie chains in highly oriented amorphous networks. A unified understanding of the cavitation processes during stretching semi‐crystalline polymers based on interpenetrated network model is proposed. Finally, this review outlooks future research topics for better understanding the cavitation mechanism to meet the industrial need.

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Section: Application Of Cavities In Semi‐crystalline Polymersmentioning

confidence: 99%

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Men

2018

Macro Materials & Eng

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“…In our previous work, different components including plasticizer [29] , poly(ethylene oxide) with low T m [24,27] , octylphenol polyoxyethylene ether that promotes the formation of microvoids in the iPP matrix [30] , calcium carbonate (CaCO 3 ) [22] and elastomer [23] , have been introduced into iPP. The microstructure evolution of samples during the annealing process and the resultant mechanical properties have been systematically investigated.…”

Section: Introductionmentioning

confidence: 99%

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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“…Inevitably, during the subsequent service period of product, the molecular chains of polymers gradually relax to achieve the thermodynamic equilibrium state. This phenomenon will result in some unpredictable changes toward the dimension stability, mechanical properties, and surface quality of product, and all of these instabilities are not to be expected …”

Section: Introductionmentioning

confidence: 99%

“…revealed that the improvement of impact strength induced by annealing treatment is mainly related to the variation of molecular chain mobility in the amorphous regions and the enhancement of β‐relaxation intensity. In addition, Chen et al . found that an amplified toughening effect can be achieved by introducing some microvoids into the annealed PP.…”

Section: Introductionmentioning

confidence: 99%

The effect of high temperature annealing process on crystallization process of polypropylene, mechanical properties, and surface quality of plastic parts

Zhao

Wú

Zhai

2015

J of Applied Polymer Sci

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This work studied the effects and action mechanism of high-temperature annealing process parameters, such as annealing temperature, annealing duration and cooling speed, on the microstructural evolution of polypropylene (PP) on different thickness layers, the surface quality, and mechanical properties of PP plastic parts. The results show that when the PP plastic parts are annealed at slightly higher than 1008C, the resin on the surface and internal layers of plastic parts just generates the relaxation and rearrangement at the molecular level. Only at an enough high annealing temperature, the secondary crystallization and phase transformation process can be observed. The crystallinity of all annealed samples is higher than that of unannealed samples, but the crystallinity is decreased with the increase of cooling speed after annealing duration, and the annealing duration exceeding 60 min almost has no effect on the crystallinity. The microstructural change of PP on the internal layer of plastic parts is weaker than that on the surface layer. The surface hardness of the plastic parts mainly depends on the crystallinity of the surface layer, whereas the surface roughness of the plastic parts depends on not only the crystallinity, but also the space conformation of molecular chains and the residual stress. With the change of annealing process parameters, the tensile and impact strengths of plastic parts show a non-monotonic change law.

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Amplified Toughening Effect of Annealing on Isotactic Polypropylene Realized by Introducing Microvoids

Cited by 18 publications

References 39 publications

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

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

The effect of high temperature annealing process on crystallization process of polypropylene, mechanical properties, and surface quality of plastic parts

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