Cargando…

Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets

The microstructure evolution of an isotactic polypropylene (iPP) sheet during solid-state stretching was studied. The transition of the spherulites—cylindrites was evaluated using in-situ two-dimensional wide-angle and small-angle X-ray scattering methods. The crystallinity of stretched iPP sheets w...

Descripción completa

Detalles Bibliográficos
Autores principales: Ji, Huajian, Zhou, Xulin, Chen, Xin, Zhao, Haili, Wang, Yu, Zhu, Huihao, Shan, Xiliang, Sha, Jin, Ma, Yulu, Xie, Linsheng
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523338/
https://www.ncbi.nlm.nih.gov/pubmed/30960603
http://dx.doi.org/10.3390/polym11040618
_version_ 1783419311220588544
author Ji, Huajian
Zhou, Xulin
Chen, Xin
Zhao, Haili
Wang, Yu
Zhu, Huihao
Shan, Xiliang
Sha, Jin
Ma, Yulu
Xie, Linsheng
author_facet Ji, Huajian
Zhou, Xulin
Chen, Xin
Zhao, Haili
Wang, Yu
Zhu, Huihao
Shan, Xiliang
Sha, Jin
Ma, Yulu
Xie, Linsheng
author_sort Ji, Huajian
collection PubMed
description The microstructure evolution of an isotactic polypropylene (iPP) sheet during solid-state stretching was studied. The transition of the spherulites—cylindrites was evaluated using in-situ two-dimensional wide-angle and small-angle X-ray scattering methods. The crystallinity of stretched iPP sheets was characterized by differential scanning calorimetry. The crystal morphology was observed by means of scanning electron microscopy. It was found that the differences of crystal microstructure of the iPP sheet depended on the stretching strain, which promoted the orientation of molecular chains. Amorphous molecular chains in the spherulites oriented and formed into a mesophase near the yield point, and the partially ordered mesophase was further stretched to form an oriented cylindrite structure after the yield point. The highest relative content of cylindrites appeared at 15% strain. Notably, as the amorphous phase embedded into the lamellae layer, the crystal size decreased with the increase of strain, which indicated that the crystallinity of the stretched iPP sheet was much higher than that of unstretched iPP sheet. The induced cylindrites structure played a more important role in improving the mechanical properties and heat resistance of iPP sheets. Compared with the unstretched iPP sheets, the tensile strength increased by 28%, the notch impact toughness significantly increased by 78%, and the vicat softening point increased from 104 to 112 °C.
format Online
Article
Text
id pubmed-6523338
institution National Center for Biotechnology Information
language English
publishDate 2019
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-65233382019-06-03 Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets Ji, Huajian Zhou, Xulin Chen, Xin Zhao, Haili Wang, Yu Zhu, Huihao Shan, Xiliang Sha, Jin Ma, Yulu Xie, Linsheng Polymers (Basel) Article The microstructure evolution of an isotactic polypropylene (iPP) sheet during solid-state stretching was studied. The transition of the spherulites—cylindrites was evaluated using in-situ two-dimensional wide-angle and small-angle X-ray scattering methods. The crystallinity of stretched iPP sheets was characterized by differential scanning calorimetry. The crystal morphology was observed by means of scanning electron microscopy. It was found that the differences of crystal microstructure of the iPP sheet depended on the stretching strain, which promoted the orientation of molecular chains. Amorphous molecular chains in the spherulites oriented and formed into a mesophase near the yield point, and the partially ordered mesophase was further stretched to form an oriented cylindrite structure after the yield point. The highest relative content of cylindrites appeared at 15% strain. Notably, as the amorphous phase embedded into the lamellae layer, the crystal size decreased with the increase of strain, which indicated that the crystallinity of the stretched iPP sheet was much higher than that of unstretched iPP sheet. The induced cylindrites structure played a more important role in improving the mechanical properties and heat resistance of iPP sheets. Compared with the unstretched iPP sheets, the tensile strength increased by 28%, the notch impact toughness significantly increased by 78%, and the vicat softening point increased from 104 to 112 °C. MDPI 2019-04-03 /pmc/articles/PMC6523338/ /pubmed/30960603 http://dx.doi.org/10.3390/polym11040618 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ji, Huajian
Zhou, Xulin
Chen, Xin
Zhao, Haili
Wang, Yu
Zhu, Huihao
Shan, Xiliang
Sha, Jin
Ma, Yulu
Xie, Linsheng
Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets
title Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets
title_full Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets
title_fullStr Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets
title_full_unstemmed Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets
title_short Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets
title_sort effects of solid-state stretching on microstructure evolution and physical properties of isotactic polypropylene sheets
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523338/
https://www.ncbi.nlm.nih.gov/pubmed/30960603
http://dx.doi.org/10.3390/polym11040618
work_keys_str_mv AT jihuajian effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT zhouxulin effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT chenxin effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT zhaohaili effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT wangyu effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT zhuhuihao effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT shanxiliang effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT shajin effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT mayulu effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets
AT xielinsheng effectsofsolidstatestretchingonmicrostructureevolutionandphysicalpropertiesofisotacticpolypropylenesheets