Effects of stereo-defect distribution on the crystalline morphology and tensile behavior of isotactic polypropylene prepared by compression molding process

Chen, Shaohua; Tang, Xu; Duan, Nannan; Wang, Luoxin; Wang, Hua; Kang, Jian

doi:10.1080/1539445x.2015.1124114

Cited by 3 publications

(4 citation statements)

References 56 publications

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“…The amount, type, and distribution of the different defects have a profound influence on the crystallization behavior and final morphology and physical properties that extends beyond the crystallisable sequence length concept.…”

Section: Introductionmentioning

confidence: 99%

Influence of 2,1‐erythro regiodefects on the crystallization behavior of isotactic polypropylene

Tranchida

Resconi

2018

Polymer Crystallization

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We produced isotactic polypropylene (iPP) samples with metallocene catalysts, containing 2,1‐erythro regiodefects between ∼0% and 3.4% and only trace amounts of stereodefects, and studied their thermal properties in order to quantify the influence of regiodefects on the crystallization behavior of iPP. Isothermal and nonisothermal experiments performed on these samples show that increasing the regiodefects content proportionally slows down crystallization rate, apparently without phase transitions or additional phenomena. The analysis of the rigid amorphous fraction and the mobile amorphous fraction however reveals a different behavior of samples containing more than ∼1.5% regiodefects, related to the inclusion of these defects in the lamellae. Additionally, the wide range of regiodefects and a novel calculation approach allowed us to estimate the equilibrium melting temperature of a fully iPP free of defects to be 206°C .

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Section: Introductionmentioning

confidence: 99%

Influence of 2,1‐erythro regiodefects on the crystallization behavior of isotactic polypropylene

Tranchida

Resconi

2018

Polymer Crystallization

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“…Based on the respective analysis in the literature, the above reversed tendencies compared to Table 6 were mainly caused by the worse dispersion of the nucleating agent, which was controlled well in this work. Furthermore, the lamellar crystals as the component unit of spherulite slipped along the axial direction as the sample was stretched, and the spherulite was deformed into an ellipsoihdal shape and the lamellar crystals became thin 50 . Elongation at break was affected by the percentage of amorphous area where chain segments moved easily, and the number of spherulites providing the deformation of lamellar crystals, where the increasing tendency with growing nucleating agent indicated that the latter was superior.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, the lamellar crystals as the component unit of spherulite slipped along the axial direction as the sample was stretched, and the spherulite was deformed into an ellipsoihdal shape and the lamellar crystals became thin. 50 Elongation at break was affected by the percentage of amorphous area where chain segments moved easily, and the number of spherulites providing the deformation of lamellar crystals, where the increasing tendency with growing nucleating agent indicated that the latter was superior. Furthermore, the digital photographs of samples at various temperatures were exhibited in Figure S4.…”

Section: Mechanical and Physical Properties Measurementmentioning

confidence: 99%

Effects of nucleating agent content on the microstructure and macroscopic performances of polypropylene analyzed by non‐isothermal crystallization behaviors and isothermal crystallization morphologies

Yang

et al. 2023

J of Applied Polymer Sci

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Direct attainment of the crystal state corresponding to desired performances in processing can improve the productivity of semi‐crystalline polymer products. This work tried to propose the idea to approach the target by exploring the effects of nucleating agent content on non‐isothermal crystallization kinetics, isothermally crystallization morphologies and macroscopic properties of polypropylene (PP). The nucleating agent content varied from 0 to 0.5 phr, and all samples were prepared by melting blending at 180°C as the antioxidant and lubricant ensured fine stability and processing. The differential scanning calorimetry results and non‐isothermal crystallization kinetics indicated that introducing 0.3 phr nucleating agent advanced both initial crystallization and melting about 10°C and improved crystallization rate and crystallinity. Besides, 145°C was determined as an isothermal crystallization condition by setting temperature gradient, and the crystallization kinetics were described by a power‐law equation well. The average crystal size was refined to 40 μm uniformly and crystallization time was reduced to 1.5 min as loading 0.5 phr nucleating agent, contributing to the significant improvements in tensile and physical properties. Thus, adding such a short‐time heat insulation procedure into the non‐isothermal cooling stage during processing can obtain desired crystal state directly with loading adequate nucleating agent.

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“…Their melting point, density, and mechanical properties differ from those of the crystalline form. Apart from the crystalline type, it is reported that the size distribution of spherulite also plays an important role in affecting the properties of PP (S. Chen et al, 2016;Sun et al, 2000;Wang et al, 2011).…”

Section: Open Accessmentioning

confidence: 99%

Development and research trends of a polypropylene material in electrical engineering: A bibliometric mapping analysis and systematical review

Duan¹,

Zhao²,

Ma³

et al. 2023

Front. Energy Res.

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In order to explore the development and research trends of polypropylene (PP) in electrical engineering, the research literature is quantitatively analyzed using a bibliometric method with the VOSviewer and CiteSpace software. First, the research literature about PP material in electrical engineering applications is collected, from 1990 to 2022. Then, by analyzing the keyword co-occurrence, keyword co-occurrence timezone, author cooperation network, and national cooperation network, the research hotspots of the PP field and its time evolutionary path and development direction are introduced. It is found that the nano-modification, mechanical, and electrical properties are the most popular research hotspots in this field. Most research studies were completed by few specific researchers. A stable cooperative group has not been formed in this field yet, indicating the necessity of further integration. Most articles about PP were published in dielectric and material journals. It is suggested that more open access journals are required to popularize the existing research results among the public and to promote the development of PP. Although the most published country is China, the United States publishes the most cited papers on average.

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Effects of stereo-defect distribution on the crystalline morphology and tensile behavior of isotactic polypropylene prepared by compression molding process

Cited by 3 publications

References 56 publications

Influence of 2,1‐erythro regiodefects on the crystallization behavior of isotactic polypropylene

Influence of 2,1‐erythro regiodefects on the crystallization behavior of isotactic polypropylene

Effects of nucleating agent content on the microstructure and macroscopic performances of polypropylene analyzed by non‐isothermal crystallization behaviors and isothermal crystallization morphologies

Development and research trends of a polypropylene material in electrical engineering: A bibliometric mapping analysis and systematical review

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