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Pochivalov K, Basko A, Lebedeva T, Yurov M, Yushkin A, Volkov A, Bronnikov S. Controlled Swelling of Monolithic Films as a Facile Approach to the Synthesis of UHMWPE Membranes. MEMBRANES 2023; 13:422. [PMID: 37103849 PMCID: PMC10145273 DOI: 10.3390/membranes13040422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 06/19/2023]
Abstract
A new method of fabricating porous membranes based on ultra-high molecular weight polyethylene (UHMWPE) by controlled swelling of the dense film was proposed and successfully utilized. The principle of this method is based on the swelling of non-porous UHMWPE film in organic solvent at elevated temperatures, followed by its cooling and further extraction of organic solvent, resulting in the formation of the porous membrane. In this work, we used commercial UHMWPE film (thickness 155 μm) and o-xylene as a solvent. Either homogeneous mixtures of the polymer melt and solvent or thermoreversible gels with crystallites acting as crosslinks of the inter-macromolecular network (swollen semicrystalline polymer) can be obtained at different soaking times. It was shown that the porous structure and filtration performance of the membranes depended on the swelling degree of the polymer, which can be controlled by the time of polymer soaking in organic solvent at elevated temperature (106 °C was found to be the optimal temperature for UHMWPE). In the case of homogeneous mixtures, the resulting membranes possessed both large and small pores. They were characterized by quite high porosity (45-65% vol.), liquid permeance of 46-134 L m-2 h-1 bar-1, a mean flow pore size of 30-75 nm, and a very high crystallinity degree of 86-89% at a decent tensile strength of 3-9 MPa. For these membranes, rejection of blue dextran dye with a molecular weight of 70 kg/mol was 22-76%. In the case of thermoreversible gels, the resulting membranes had only small pores located in the interlamellar spaces. They were characterized by a lower crystallinity degree of 70-74%, a moderate porosity of 12-28%, liquid permeability of up to 12-26 L m-2 h-1 bar-1, a mean flow pore size of up to 12-17 nm, and a higher tensile strength of 11-20 MPa. These membranes demonstrated blue dextran retention of nearly 100%.
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Affiliation(s)
- Konstantin Pochivalov
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, 1 ul. Akademicheskaya, 153045 Ivanovo, Russia; (A.B.)
| | - Andrey Basko
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, 1 ul. Akademicheskaya, 153045 Ivanovo, Russia; (A.B.)
| | - Tatyana Lebedeva
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, 1 ul. Akademicheskaya, 153045 Ivanovo, Russia; (A.B.)
| | - Mikhail Yurov
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, 1 ul. Akademicheskaya, 153045 Ivanovo, Russia; (A.B.)
| | - Alexey Yushkin
- A.V. Topchiev Institute of Petrochemical Synthesis of the Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia
| | - Alexey Volkov
- A.V. Topchiev Institute of Petrochemical Synthesis of the Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia
- Biological and Environmental Science, and Engineering Division (BESE), Advanced Membranes and Porous Materials Center (AMPM), King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Sergei Bronnikov
- Institute of Macromolecular Compounds of the Russian Academy of Sciences, 31 Bolshoy pr., 199004 St. Petersburg, Russia
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Gimenis de Moura L, Alberto Fancello E, da Rosa E, Rodrigo de Mello Roesler C, Muniz da Silva de Almeida C, Marie Maru de Morais M. Influence of plane-strain compression on the microstructure and tribological behavior of GUR 1050 UHMWPE. J Mech Behav Biomed Mater 2023; 142:105816. [PMID: 37062097 DOI: 10.1016/j.jmbbm.2023.105816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/24/2023] [Accepted: 03/26/2023] [Indexed: 04/08/2023]
Abstract
Ultra-high molecular weight polyethylene (UHMWPE) has been used as a bearing surface in orthopedic implants due to its outstanding physical and mechanical properties. Modifications in the structure of the polymer have a direct effect on its wear. In this work, plane-strain compression in a channel die was applied to induce microstructural changes in specimens of UHMWPE GUR 1050. These structural changes were characterized using a combined approach involving Raman spectroscopy and atomic force microscopy. These qualitative and quantitative characterization resulted in a valuable understanding of the changes in the material microstructure when subjected to plastic deformation. A molecular non-uniform alignment of the UHMWPE molecules, with fragmentation and kinking of polymer lamellae, was observed in the direction of material flow, perpendicular to the compressive load direction, following an inhomogeneous strain field generated by the mechanical compression. The microstructural analyses revealed an increased crystalline content and decreased intermediate phase while amorphous phase content remained unchanged, in all the regions of the deformed specimen. The tribological performance, evaluated by the scratch resistance force, decreased along the material flow direction and increased along the load direction in the deformed polymer compared to that of the uncompressed polymer. Plane-strain compression was able to modify the polymer microstructure, introducing directional anisotropy in its tribological behavior that can impact the wear performance of the material.
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Yan F, Li H, Cui S, Sun J, Ye Q, Liu Y, Liu C, Wang Z. Effects of combined melt stretching and fast cooling fields on crystallization of high-density polyethylene. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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4
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Wu H, Liao T, Zhu B, Su W, Lu Y, Men Y. Reversed thermal stability between stress-induced melting and recrystallized crystallites and original inclined ones in moderately stretched ultra high molecular weight polyethylene and high density polyethylene. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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Plastic Deformation of High Density Polyethylene with Extended-Chain Crystal Morphology. Polymers (Basel) 2022; 15:polym15010066. [PMID: 36616416 PMCID: PMC9824363 DOI: 10.3390/polym15010066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022] Open
Abstract
Samples of polyethylene with extended-chain crystal morphology, obtained by crystallization under high pressure, were subjected to uniaxial compression to various strains. Accompanying structural changes were analyzed using scanning electron microscopy. At the true strain of e = 0.2−0.3 the microbuckling instability was observed in longitudinally loaded lamellae, resulting in the formation of angular kinks. This induced a rapid reorientation of the lamellae, facilitating their further deformation by crystallographic slip. Microbuckling instability was found to occur earlier than in samples with folded-chain crystal morphology (e = 0.3−0.4) due to a smaller ratio of the amorphous to crystalline layer thickness. SEM observations demonstrated that the microbuckling instability begins with small undulation in long lamellae. Sharp angular lamellar kinks develop from the initial undulation through intense plastic deformation by crystallographic slip along the chain direction. The same slip system was found to operate throughout the kink, including the tip region as well as both limbs. In contrast to thin folded-chain lamellae that often undergo fragmentation during deformation, the thick extended-chain lamellae deform stably by chain slip and retain their continuity up to high strains, e > 1.6. This stability of deformation is related to the large thickness of extended-chain lamellae.
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Yang F, Liu C, Yang F, Xiang M, Wu T, Fu Q. Effects of diluent content on the crystallization behavior and morphology of polyethylene membrane fabricated via thermally induced phase separation process. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Xiang P, Fan L, Li S, Cao N, Wan C, Bi S, Chen X, Yu P. Preparation of poly(lactic acid) with excellent comprehensive properties via simple deformation or microfibrillation of spherulites. J Appl Polym Sci 2022. [DOI: 10.1002/app.51539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Pei Xiang
- Hubei Provincial Key Laboratory of Green Materials for Light Industry, Collaborative Innovation Center of Green Light‐weight Materials and Processing, School of Materials and Chemical Engineering Hubei University of Technology Wuhan China
| | - Lijun Fan
- Hubei Provincial Key Laboratory of Green Materials for Light Industry, Collaborative Innovation Center of Green Light‐weight Materials and Processing, School of Materials and Chemical Engineering Hubei University of Technology Wuhan China
| | - Shen Li
- Hubei Provincial Key Laboratory of Green Materials for Light Industry, Collaborative Innovation Center of Green Light‐weight Materials and Processing, School of Materials and Chemical Engineering Hubei University of Technology Wuhan China
| | - Nuo Cao
- China National Electric Apparatus Research Institute Co., Ltd. Guangzhou P. R. China
| | - Chao Wan
- China National Electric Apparatus Research Institute Co., Ltd. Guangzhou P. R. China
| | - Siwen Bi
- Hubei Provincial Key Laboratory of Green Materials for Light Industry, Collaborative Innovation Center of Green Light‐weight Materials and Processing, School of Materials and Chemical Engineering Hubei University of Technology Wuhan China
| | - Xuhang Chen
- Hubei Provincial Key Laboratory of Green Materials for Light Industry, Collaborative Innovation Center of Green Light‐weight Materials and Processing, School of Materials and Chemical Engineering Hubei University of Technology Wuhan China
| | - Peng Yu
- Hubei Provincial Key Laboratory of Green Materials for Light Industry, Collaborative Innovation Center of Green Light‐weight Materials and Processing, School of Materials and Chemical Engineering Hubei University of Technology Wuhan China
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Yagi S, Oguro M, Tokita M. Stress Response and Deformation of Block Copolymer Lamellae on Stretching in Normal Direction: Effects of Lateral Size of Lamellae. MACROMOL CHEM PHYS 2022. [DOI: 10.1002/macp.202100399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Seiichiro Yagi
- S. Yagi, M. Oguro, Prof. M. Tokita Department of Chemical Science and Engineering Tokyo Institute of Technology Ookayama, Meguro Tokyo 152–8550 Japan
| | - Masaaki Oguro
- S. Yagi, M. Oguro, Prof. M. Tokita Department of Chemical Science and Engineering Tokyo Institute of Technology Ookayama, Meguro Tokyo 152–8550 Japan
| | - Masatoshi Tokita
- S. Yagi, M. Oguro, Prof. M. Tokita Department of Chemical Science and Engineering Tokyo Institute of Technology Ookayama, Meguro Tokyo 152–8550 Japan
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Iqbal O, Guo H, Chen W. Structural Origin of Double Yielding: The Critical Role of Crystallite Aggregate Heterogeneity. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Obaid Iqbal
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Hang Guo
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Wei Chen
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
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10
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Liao T, Yang X, Zhao X, Tang Y, Jiang Z, Men Y. Gaussian and Non-Gaussian Distributions of Fracture Properties in Tensile Stretching of High-Density Polyethylene. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00944] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Tao Liao
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China
| | - Xiao Yang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China
- University of Science and Technology of China, Hefei 230026, China
| | - Xintong Zhao
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China
- University of Science and Technology of China, Hefei 230026, China
| | - Yujing Tang
- Sinopec Beijing Research Institute of Chemical Industry, Beijing 100013, China
| | - Zhiyong Jiang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China
| | - Yongfeng Men
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China
- University of Science and Technology of China, Hefei 230026, China
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11
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Enhancing Chain Mobility of Ultrahigh Molecular Weight Polyethylene by Regulating Residence Time under a Consecutive Elongational Flow for Improved Processability. Polymers (Basel) 2021; 13:polym13132192. [PMID: 34209419 PMCID: PMC8271948 DOI: 10.3390/polym13132192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022] Open
Abstract
Improving the processability of ultrahigh molecular weight polyethylene (UHMWPE) and understanding the effect of the polymeric chain mobility has long been a challenging task. Herein, we show that UHMWPE without any processing aids can be processed at a lower temperature of 180 °C compared to conventional processing temperatures (~250 °C) under a continuous elongational flow (CEF) by using an eccentric rotor extruder (ERE). By probing the effect of the residence time of UHMWPE samples under a CEF on the morphology, rheological behavior and molecular orientation, we find that the long polymer chains of UHMWPE are apt to orientate under a consecutive volume elongational deformation, thereby leading to a higher residual stress for the extruded sample. Meanwhile, the residence time of samples can regulate the polymeric chain mobility, giving rise to the simultaneous decrease of the melting defects and residual stress as well as Hermans orientation function with increasing residence time from 0 to 60 s. This also engenders the enhanced diffusion of UHMWPE segments, resulting in a defect-free morphology and higher entanglement with lower crystallinity but without causing obvious thermal oxidative degradation of UHMWPE. This interesting result could originate from the fast chain entanglement and particle welding enabled by a desirably short residence time, which could be explained by the empirical, entropy-driven melting explosion mechanism.
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Chen X, Wang X, Cao C, Yuan Z, Yu D, Li F, Chen X. Elongational Flow Field Processed Ultrahigh Molecular Weight Polyethylene/Polypropylene Blends with Distinct Interlayer Phase for Enhanced Tribological Properties. Polymers (Basel) 2021; 13:1933. [PMID: 34200942 PMCID: PMC8230468 DOI: 10.3390/polym13121933] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/05/2021] [Accepted: 06/06/2021] [Indexed: 02/06/2023] Open
Abstract
Herein, we produced a series of ultrahigh molecular weight polyethylene/polypropylene (UHMWPE/PP) blends by elongational-flow-field dominated eccentric rotor extruder (ERE) and shear-flow-field dominated twin screw extruder (TSE) respectively and presented a detailed comparative study on microstructures and tribological properties of UHMWPE/PP by different processing modes. Compared with the shear flow field in TSE, the elongational flow field in ERE facilitates the dispersion of PP in the UHMWPE matrix and promotes the interdiffusion of UHMWPE and PP molecular chains. For the first time, we discovered the presence of the interlayer phase in blends with different processing modes by using Raman mapping inspection. The elongational flow field introduces strong interaction to enable excellent compatibility of UHMWPE and PP and induces more pronounced interlayer phase with respect to the shear flow field, eventually endowing UHMWPE/PP with improved wear resistance. The optimized UHMWPE/PP (85/15) blend processed by ERE displayed higher tensile strength (25.3 MPa), higher elongation at break (341.77%) and lower wear loss of ERE-85/15 (1.5 mg) compared to the blend created by TSE. By systematically investigating the microstructures and mechanical properties of blends, we found that with increased content of PP, the wear mechanism of blends varies from abrasive wear, fatigue wear, to adhesion wear as the dominant mechanism for two processing modes.
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Affiliation(s)
- Xiaochuan Chen
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (X.C.); (X.W.); (Z.Y.)
- Key Laboratory of High Performance Polymerbased Composites of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xiaotong Wang
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (X.C.); (X.W.); (Z.Y.)
- Key Laboratory of High Performance Polymerbased Composites of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Changlin Cao
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China;
- Engineering Research Center of Polymer Green Recycling of Ministry of Education, Fujian Normal University, Fuzhou 350007, China
| | - Zhongke Yuan
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (X.C.); (X.W.); (Z.Y.)
- Key Laboratory of High Performance Polymerbased Composites of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Dingshan Yu
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (X.C.); (X.W.); (Z.Y.)
- Key Laboratory of High Performance Polymerbased Composites of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Fei Li
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China;
- Engineering Research Center of Polymer Green Recycling of Ministry of Education, Fujian Normal University, Fuzhou 350007, China
| | - Xudong Chen
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China; (X.C.); (X.W.); (Z.Y.)
- Key Laboratory of High Performance Polymerbased Composites of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
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Chen M, Chen Y, Li W, Liang P, Ren C, Jiang B, Wang J, Yang Y. Synthesis of Weakly Entangled Ultra-High-Molecular-Weight Polyethylene with a Fine Particle Size. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c05838] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mei Chen
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- Ningbo Key Laboratory of Specialty Polymers, School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, P.R. China
| | - Yuming Chen
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, P. R. China
| | - Wei Li
- Ningbo Key Laboratory of Specialty Polymers, School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, P.R. China
| | - Peng Liang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- Ningbo Key Laboratory of Specialty Polymers, School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, P.R. China
| | - Congjing Ren
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, P. R. China
| | - Binbo Jiang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Jingdai Wang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, P. R. China
| | - Yongrong Yang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
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Iqbal O, Habumugisha JC, Feng S, Lin Y, Chen W, Yu W, Li L. Microstructural Origin of the Double Yield Points of the Metallocene Linear Low-Density Polyethylene (mLLDPE) Precursor Film under Uniaxial Tensile Deformation. Polymers (Basel) 2020; 13:polym13010126. [PMID: 33396888 PMCID: PMC7794766 DOI: 10.3390/polym13010126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/25/2020] [Accepted: 12/25/2020] [Indexed: 11/16/2022] Open
Abstract
The microstructural origin of the double yield points of metallocene linear low-density polyethylene (mLLDPE) precursor films has been studied with the assistance of the synchrotron radiation small- and wide-angle X-ray scattering (SAXS/WAXS). It has been shown that the microstructural origin of the double yield points is highly related to the initial orientation of the original precursor film. For less oriented mLLDPE precursor films, the rearrangement of lamellae and the appearance of the monoclinic phase are the microstructural origins of the first yield point. In comparison, for the highly-oriented mLLDPE precursor film, only the orthorhombic-monoclinic phase transition appears at the first yield point. The melting-recrystallization and the formation of the fibrillary structure happen beyond the second yield point for all studied mLLDPE precursor films. Finally, the detailed microstructural evolution roadmaps of mLLDPE precursor films under uniaxial tensile deformation have been established, which might serve as a guide for processing high-performance polymer films by post-stretching.
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Affiliation(s)
- Obaid Iqbal
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China; (O.I.); (J.C.H.); (S.F.); (Y.L.); (W.C.)
| | - Jean Claude Habumugisha
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China; (O.I.); (J.C.H.); (S.F.); (Y.L.); (W.C.)
| | - Shengyao Feng
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China; (O.I.); (J.C.H.); (S.F.); (Y.L.); (W.C.)
| | - Yuanfei Lin
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China; (O.I.); (J.C.H.); (S.F.); (Y.L.); (W.C.)
- South China Advanced Institute for Soft Matter Science and Technology, School of Molecular Science and Engineering, Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Wei Chen
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China; (O.I.); (J.C.H.); (S.F.); (Y.L.); (W.C.)
| | - Wancheng Yu
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China; (O.I.); (J.C.H.); (S.F.); (Y.L.); (W.C.)
- Correspondence: (W.Y.); (L.L.)
| | - Liangbin Li
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China; (O.I.); (J.C.H.); (S.F.); (Y.L.); (W.C.)
- Correspondence: (W.Y.); (L.L.)
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Microbuckling Instability and the Second Yield during the Deformation of Semicrystalline Polyethylene. Polymers (Basel) 2020; 12:polym12102208. [PMID: 32993078 PMCID: PMC7599652 DOI: 10.3390/polym12102208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/22/2020] [Accepted: 09/24/2020] [Indexed: 11/16/2022] Open
Abstract
Deformation instabilities, such as microbuckling or lamellar fragmentation due to slip localization, play a very important role in the deformation of semicrystalline polymers, although it still not well explored. Such instabilities often appear necessary to modify the deformation path and facilitate strain accommodation in an energy-minimizing manner. In this work, microbuckling instability was investigated using partially oriented, injection-molded (IM) samples of high-density polyethylene, deformed by a plane-strain compression. Deformed samples were probed by SEM, X-ray (small- and wide-angle X-ray scattering: SAXS, WAXS), and differential scanning calorimetry (DSC). It was found that microbuckling instability, followed quickly by the formation of lamellar kinks, occurred in high-density polyethylene (HDPE) at a true strain of about e = 0.3–0.4, mainly in those lamellar stacks which were initially oriented parallel to the compression direction. This phenomenon was observed with scanning electron microscopy, especially in the oriented skin layers of IM specimens, where a chevron morphology resulting from lamellae microbuckling/kinking was evidenced. Macroscopically, this instability manifested as the so-called “second macroscopic yield” in the form of a hump in the true stress–true strain curve. Microbuckling instability can have a profound effect on the subsequent stages of the deformation process, as well as the resulting structure. This is particularly important in deforming well-oriented lamellar structures—e.g., in drawing pre-oriented films of a semicrystalline polymer, a process commonly used in many technologies.
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