The Important Role of Molecular Chain Relaxation in the Preparation of High-performance Biaxially Oriented Polypropylene Films

Yan-xu Wang; Yue-hao Li; Wei Xu; Qiang Fu

doi:10.11777/j.issn1000-3304.2025.25259

您当前的位置：

首页 >

文章列表页 >

The Important Role of Molecular Chain Relaxation in the Preparation of High-performance Biaxially Oriented Polypropylene Films

Research Article | 更新时间：2026-01-16

- The Important Role of Molecular Chain Relaxation in the Preparation of High-performance Biaxially Oriented Polypropylene Films
- Acta Polymerica Sinica Vol. 57, Issue 1, Pages: 268-281(2026)
- 作者机构：
  
  1.四川大学高分子科学与工程学院先进高分子材料全国重点实验室成都 610065
  2.四川大学匹兹堡学院成都 610065
  3.宜宾天亿新材料科技有限公司宜宾 644000
- 作者简介：
  
  Qiang Fu, E-mail: qiangfu@scu.edu.cn
- 基金信息：
- DOI：10.11777/j.issn1000-3304.2025.25259
  CLC：
- CSTR：32057.14.GFZXB.2025.7514
- Received：11 October 2025，
  
  Accepted：10 November 2025，
  
  Published Online：19 December 2025，
  
  Published：20 January 2026
- 稿件说明：
移动端阅览
王岩旭, 李悦昊, 徐伟, 傅强. 分子链松弛在制备高性能双向拉伸聚丙烯薄膜中的重要作用. 高分子学报, 2026, 57(1), 268-281.

Wang, Y. X.; Li, Y. H.; Xu, W.; Fu, Q. The important role of molecular chain relaxation in the preparation of high-performance biaxially oriented polypropylene films. Acta Polymerica Sinica (in Chinese), 2026, 57(1), 268-281.
王岩旭, 李悦昊, 徐伟, 傅强. 分子链松弛在制备高性能双向拉伸聚丙烯薄膜中的重要作用. 高分子学报, 2026, 57(1), 268-281. DOI： 10.11777/j.issn1000-3304.2025.25259. CSTR： 32057.14.GFZXB.2025.7514.

Wang, Y. X.; Li, Y. H.; Xu, W.; Fu, Q. The important role of molecular chain relaxation in the preparation of high-performance biaxially oriented polypropylene films. Acta Polymerica Sinica (in Chinese), 2026, 57(1), 268-281. DOI： 10.11777/j.issn1000-3304.2025.25259. CSTR： 32057.14.GFZXB.2025.7514.

摘要

双向拉伸聚丙烯(BOPP)由于优异的电学、力学与光学性能，薄膜广泛应用在包装、电气与医疗等领域. 超强和超薄是塑料薄膜加工的前沿方向，但传统的一步双向拉伸工艺中，高拉伸比下分子链难以及时响应宏观应变，解缠结困难，易产生应力集中导致破膜，难以制得超强和超薄的聚丙烯薄膜. 本研究以等规聚丙烯(

PP)铸片为原料，采用同步双向拉伸技术，设计“拉伸—暂停—再拉伸”的间歇式拉伸工艺，在拉伸过程中引入松弛，通过调控间歇温度与间歇时间，控制松弛程度，研究松弛对BOPP拉伸过程、微观晶体结构及力学性能的影响. 结果表明，拉伸过程中引入松弛为分子链构象调整提供时间，有效缓解局部应力并提升最大拉伸比：存在一个最佳松弛状态，可以平衡分子链解缠结与新晶体形成的竞争. 采用该拉伸工艺可以获得高拉伸比、力学强度更高，厚度更薄的BOPP薄膜. 本研究为超强超薄高性能BOPP薄膜的制备提供新工艺新技术.

Abstract

Owing to its excellent electrical

mechanical

and optical properties

biaxially oriented polypropylene (BOPP) films are widely used in fields such as packaging

electrical engineering

and medical care. Ultra-high strength and ultra-thinness represent the cutting-edge directions in plastic film processing. However

in the traditional one-step biaxial stretching process

the molecular chains struggle to respond promptly to macroscopic strain under high stretch ratios

making it difficult for them to disentangle. This easily leads to stress concentration and subsequent film breakage

posing challenges to the preparation of ultra-high-strength and ultra-thin polypropylene films. In this study

isotactic polypropylene (

PP) castings were used as raw materials

and synchronous biaxial stretching technology was adopted. An intermittent stretching process featuring "stretching-pausing-restretching" was designed

where relaxation was introduced during the stretching process. By regulating the intermittent temperature and intermittent time

the relaxation degree was controlled

and the effects of relaxation on the stretching process

crystalline structure

and mechanical properties of BOPP were investigated. The results showed that the introduction of relaxation during the stretching process provided time for the conformational adjustment of molecular chains

effectively alleviating local stress and increasing the maximum stretch ratio. There existed an optimal relaxation state that balances the competition between molecular chain disentanglement and the formation of new crystals. Using this stretching process

BOPP films with high stretch ratios

higher mechanical strength

and thinner thickness could be obtained. This work provides a new process and technology for the prepara

tion of ultra-high-strength

ultra-thin

and high-performance BOPP films.

关键词

Keywords

references

DeMeuse, M. T. Biaxial stretching of film: principles and applications . Cambridge : Woodhead Publishing , 2011 . doi: 10.1533/9780857092953.1.59 http://dx.doi.org/10.1533/9780857092953.1.59

Breil J. Biaxially oriented films for packaging applications . Plastic Films in Food Packaging. Amsterdam : Elsevier , 2013 , 53 - 70 . doi: 10.1016/b978-1-4557-3112-1.00004-1 http://dx.doi.org/10.1016/b978-1-4557-3112-1.00004-1

Matsui K. ; Hosaka N. ; Suzuki K. ; Shinohara Y. ; Amemiya Y. Microscopic deformation behavior of hard elastic polypropylene during cold-stretching process in fabrication of microporous membrane as revealed by synchrotron X-ray scattering . Polymer , 2015 , 70 , 215 - 221 . doi: 10.1016/j.polymer.2015.06.034 http://dx.doi.org/10.1016/j.polymer.2015.06.034

Matsui K. ; Bando A. ; Sakurai T. ; Shinohara Y. ; Maruyama T. ; Masunaga H. ; Amemiya Y. Macroscopically homogeneous deformation in injection molded polypropylene induced by annealing studied with microbeam X-ray scattering . Polymer , 2015 , 70 , 315 - 325 . doi: 10.1016/j.polymer.2015.06.039 http://dx.doi.org/10.1016/j.polymer.2015.06.039

Xu J. ; Mittal V. ; Bates F. S. Toughened isotactic polypropylene: phase behavior and mechanical properties of blends with strategically designed random copolymer modifiers . Macromolecules , 2016 , 49 ( 17 ), 6497 - 6506 . doi: 10.1021/acs.macromol.6b01521 http://dx.doi.org/10.1021/acs.macromol.6b01521

Wu T. ; Wang K. ; Chen X. F. ; Yang X. M. ; Xiang M. ; Fu Q. Practicing the concept of "structuring" processing in the manufacture of polymer films . Sci. China Chem. , 2023 , 66 ( 4 ), 993 - 1010 . doi: 10.1007/s11426-022-1520-9 http://dx.doi.org/10.1007/s11426-022-1520-9

Wang J. Q. ; Guo H. X. ; Zeng S. X. ; Du J. Q. ; Zhang Q. ; Wang K. Thin, largescale processed, high-temperature resistant capacitor films based on polypropylene/cycloolefin copolymer blend . Chem. Eng. J. , 2024 , 492 , 152237 . doi: 10.1016/j.cej.2024.152237 http://dx.doi.org/10.1016/j.cej.2024.152237

Hong W. ; Ran L. B. ; Yu G. Y. ; Qin J. X. ; Ma B. J. ; Wu H. ; Guo S. Y. ; Li C. H. Superior low-temperature mechanical toughness of the PP-based blown micro/nano layer films . Polymer , 2022 , 256 , 125257 . doi: 10.1016/j.polymer.2022.125257 http://dx.doi.org/10.1016/j.polymer.2022.125257

van Drongelen M. ; Cavallo D. ; Balzano L. ; Portale G. ; Vittorias I. ; Bras W. ; Alfonso G. C. ; Peters G. W. M. Structure development of low-density polyethylenes during film blowing: a real-time wide-angle X-ray diffraction study . Macromol. Mater. Eng. , 2014 , 299 ( 12 ), 1494 - 1512 . doi: 10.1002/mame.201400161 http://dx.doi.org/10.1002/mame.201400161

Zhao H. Y. ; Li L. F. ; Zhang Q. L. ; Xia Z. J. ; Yang E. J. ; Wang Y. S. ; Chen W. ; Meng L. P. ; Wang D. L. ; Li L. B. Manipulation of chain entanglement and crystal networks of biodegradable poly(butylene adipate- co -butylene terephthalate) during film blowing through the addition of a chain extender: an in situ synchrotron radiation X-ray scattering study . Biomacromolecules , 2019 , 20 ( 10 ), 3895 - 3907 . doi: 10.1021/acs.biomac.9b00975 http://dx.doi.org/10.1021/acs.biomac.9b00975

Bartczak Z. ; Galeski A. Yield and plastic resistance of α -crystals of isotactic polypropylene . Polymer , 1999 , 40 ( 13 ), 3677 - 3684 . doi: 10.1016/s0032-3861(98)00614-4 http://dx.doi.org/10.1016/s0032-3861(98)00614-4

Lotz B. α and β phases of isotactic polypropylene: a case of growth kinetics 'phase reentrency' in polymer crystallization . Polymer , 1998 , 39 ( 19 ), 4561 - 4567 . doi: 10.1016/s0032-3861(97)10147-1 http://dx.doi.org/10.1016/s0032-3861(97)10147-1

De Gennes P. G. Coil-stretch transition of dilute flexible polymers under ultrahigh velocity gradients . J. Chem. Phys. , 1974 , 60 ( 12 ), 5030 - 5042 . doi: 10.1063/1.1681018 http://dx.doi.org/10.1063/1.1681018

Keller A. ; Kolnaar J. W. H. Chain extension and orientation: fundamentals and relevance to processing and products . Orientational Phenomena in Polymers. Darmstadt : Steinkopff, 2007 , 81 - 102 .

Lin Y. F. ; Meng L. P. ; Wu L. H. ; Li X. Y. ; Chen X. W. ; Zhang Q. L. ; Zhang R. ; Zhang W. H. ; Li L. B. A semi-quantitative deformation model for pore formation in isotactic polypropylene microporous membrane . Polymer , 2015 , 80 , 214 - 227 . doi: 10.1016/j.polymer.2015.10.067 http://dx.doi.org/10.1016/j.polymer.2015.10.067

Chen X. D. ; Xu R. J. ; Xie J. Y. ; Lin Y. F. ; Lei C. H. ; Li L. B. The study of room-temperature stretching of annealed polypropylene cast film with row-nucleated crystalline structure . Polymer , 2016 , 94 , 31 - 42 . doi: 10.1016/j.polymer.2016.04.054 http://dx.doi.org/10.1016/j.polymer.2016.04.054

Ma Z. ; Shao C. G. ; Wang X. ; Zhao B. J. ; Li X. Y. ; An H. N. ; Yan T. Z. ; Li Z. M. ; Li L. B. Critical stress for drawing-induced α crystal-mesophase transition in isotactic polypropylene . Polymer , 2009 , 50 ( 12 ), 2706 - 2715 . doi: 10.1016/j.polymer.2009.04.010 http://dx.doi.org/10.1016/j.polymer.2009.04.010

Geng Y. ; Wang G. L. ; Cong Y. H. ; Bai L. G. ; Li L. B. ; Yang C. L. Shear-induced nucleation and growth of long helices in supercooled isotactic polypropylene . Macromolecules , 2009 , 42 ( 13 ), 4751 - 4757 . doi: 10.1021/ma9004567 http://dx.doi.org/10.1021/ma9004567

Chen Q. ; Wang Z. W. ; Zhang S. M. ; Cao Y. ; Chen J. Y. Structure evolution and deformation behavior of polyethylene film during biaxial stretching . ACS Omega , 2020 , 5 ( 1 ), 655 - 666 . doi: 10.1021/acsomega.9b03250 http://dx.doi.org/10.1021/acsomega.9b03250

Zhu J. H. ; Han X. Q. ; Cheng H. ; Guo H. ; Chen J. G. ; Yu W. C. ; Li L. B. ; Cui K. P. Unraveling the biaxial deformation mechanism of isotactic polypropylene film via in situ synchrotron radiation X-ray scattering . Polymer , 2025 , 327 , 128411 . doi: 10.1016/j.polymer.2025.128411 http://dx.doi.org/10.1016/j.polymer.2025.128411

An H. ; Guo J. ; Gao J. W. ; Zhong Y. S. ; Li Y. G. ; Wang Z. B. Structural evolution of biaxially oriented polypropylene films upon asynchronous stretching . J. Polym. Sci. , 2024 , 62 ( 17 ), 3947 - 3958 . doi: 10.1002/pol.20240332 http://dx.doi.org/10.1002/pol.20240332

Tabatabaei S. H. ; Carreau P. J. ; Ajji A. Microporous membranes obtained from polypropylene blend films by stretching . J. Membr. Sci. , 2008 , 325 ( 2 ), 772 - 782 . doi: 10.1016/j.memsci.2008.09.001 http://dx.doi.org/10.1016/j.memsci.2008.09.001

Yalcin B. ; Cakmak M. Molecular orientation behavior of poly(vinyl chloride) as influenced by the nanoparticles and plasticizer during uniaxial film stretching in the rubbery stage . J. Polym. Sci. Part B Polym. Phys. , 2005 , 43 ( 6 ), 724 - 742 . doi: 10.1002/polb.20369 http://dx.doi.org/10.1002/polb.20369

Rozanski A. ; Galeski A. Controlling cavitation of semicrystalline polymers during tensile drawing . Macromolecules , 2011 , 44 ( 18 ), 7273 - 7287 . doi: 10.1021/ma201090z http://dx.doi.org/10.1021/ma201090z

Rozanski A. ; Krajenta A. ; Idczak R. ; Galeski A. Physical state of the amorphous phase of polypropylene-influence on free volume and cavitation phenomenon . J. Polym. Sci. Part B Polym. Phys. , 2016 , 54 ( 5 ), 531 - 543 . doi: 10.1002/polb.23911 http://dx.doi.org/10.1002/polb.23911

Li R. L. ; Wang Z. R. ; Sun W. L. ; Zhang H. ; Zeng Y. W. ; Zhao X. X. ; Hu W. B. ; Deng H. ; Loh K. P. ; Fu Q. Scalable production of critically thin polyethylene films via multistep stretching . Nat. Chem. Eng. , 2024 , 1 ( 11 ), 702 - 709 . doi: 10.1038/s44286-024-00139-w http://dx.doi.org/10.1038/s44286-024-00139-w

Zhang D. X. ; Fan H. ; Zhang Z. H. ; Cao Y. ; Wu T. ; Fu Q. A practical technique to manufacture biaxially oriented high-density polyethylene film via precise control of amorphous region . Polymer , 2025 , 325 , 128309 . doi: 10.1016/j.polymer.2025.128309 http://dx.doi.org/10.1016/j.polymer.2025.128309

Kuriyagawa M. ; Nitta K. H. Structural explanation on natural draw ratio of metallocene-catalyzed high density polyethylene . Polymer , 2011 , 52 ( 15 ), 3469 - 3477 . doi: 10.1016/j.polymer.2011.05.028 http://dx.doi.org/10.1016/j.polymer.2011.05.028

Stern C. ; Frick A. R. ; Weickert G. ; Michler G. H. ; Henning S. Processing, morphology, and mechanical properties of liquid pool polypropylene with different molecular weights . Macromol. Mater. Eng. , 2005 , 290 ( 6 ), 621 - 635 . doi: 10.1002/mame.200500081 http://dx.doi.org/10.1002/mame.200500081

Fayolle B. ; Tcharkhtchi A. ; Verdu J. Temperature and molecular weight dependence of fracture behaviour of polypropylene films . Polym. Test. , 2004 , 23 ( 8 ), 939 - 947 . doi: 10.1016/j.polymertesting.2004.04.013 http://dx.doi.org/10.1016/j.polymertesting.2004.04.013

Lei C. H. ; Wu S. Q. ; Xu R. J. ; Peng X. L. ; Shi W. Q. ; Hu B. Influence of low molecular weight tail of polypropylene resin on the pore structure by room-temperature stretching . Polym. Eng. Sci. , 2013 , 53 ( 12 ), 2594 - 2602 . doi: 10.1002/pen.23527 http://dx.doi.org/10.1002/pen.23527

Xu L. L. ; Xu K. ; Zhang X. J. ; Liu F. Y. ; Chen M. C. The mechanism for fracture resistance in β -nucleated isotactic polypropylene . Polym. Adv. Technol. , 2010 , 21 ( 11 ), 807 - 816 . doi: 10.1002/pat.1506 http://dx.doi.org/10.1002/pat.1506

Cheng S. Z. D. ; Janimak J. J. ; Zhang A. Q. ; Hsieh E. T. Isotacticity effect on crystallization and melting in polypropylene fractions: 1. crystalline structures and thermodynamic property changes . Polymer , 1991 , 32 ( 4 ), 648 - 655 . doi: 10.1016/0032-3861(91)90477-z http://dx.doi.org/10.1016/0032-3861(91)90477-z

Patterson A. L. X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials . J. Am. Chem. Soc. , 1955 , 77 ( 7 ), 2030 - 2031 . doi: 10.1021/ja01612a110 http://dx.doi.org/10.1021/ja01612a110

Han R. ; Nie M. ; Wang Q. ; Yan S. Self-assembly β nucleating agent induced polymorphic transition from α -form shish kebab to β -form highly ordered lamella under intense shear field . Ind. Eng. Chem. Res. , 2017 , 56 ( 10 ), 2764 - 2772 . doi: 10.1021/acs.iecr.6b04908 http://dx.doi.org/10.1021/acs.iecr.6b04908

Huo H. ; Jiang S. C. ; An L. J. ; Feng J. C. Influence of shear on crystallization behavior of the β phase in isotactic polypropylene with β -nucleating agent . Macromolecules , 2004 , 37 ( 7 ), 2478 - 2483 . doi: 10.1021/ma0358531 http://dx.doi.org/10.1021/ma0358531

Zhang W. ; Xu M. ; Huang K. W. ; Mu Q. L. ; Chen G. Effect of β -crystals on the mechanical and electrica properties of β -nucleated isotactic polypropylene . IEEE Trans. Dielectr. Electr. Insul. , 2019 , 26 ( 3 ), 714 - 721 . doi: 10.1109/tdei.2018.007632 http://dx.doi.org/10.1109/tdei.2018.007632

Varga J. β -modification of isotactic polypropylene: preparation, structure, processing, properties, and application . J. Macromol. Sci. Part B , 2002 , 41 ( 4-6 ), 1121 - 1171 . doi: 10.1081/mb-120013089 http://dx.doi.org/10.1081/mb-120013089

Zhang C. B. ; Liu G. M. ; Song Y. ; Zhao Y. ; Wang D. J. Structural evolution of β - i PP during uniaxial stretching studied by in - situ WAXS and SAXS . Polymer , 2014 , 55 ( 26 ), 6915 - 6923 . doi: 10.1016/j.polymer.2014.10.049 http://dx.doi.org/10.1016/j.polymer.2014.10.049

Karger-kocsis J. ; Varga J. Effects of β - α transformation on the static and dynamic tensile behavior of isotactic polypropylene . J. Appl. Polym. Sci. , 1996 , 62 ( 2 ), 291 - 300 . doi: 10.1002/(sici)1097-4628(19961010)62:2<291::aid-app4>3.0.co;2-s http://dx.doi.org/10.1002/(sici)1097-4628(19961010)62:2<291::aid-app4>3.0.co;2-s

Shi G. Y. ; Chu F. ; Zhou G. E. ; Han Z. W. Plastic deformation and solid-phase transformation in β -phase polypropylene . Die Makromol. Chem. , 1989 , 190 ( 4 ), 907 - 913 . doi: 10.1002/macp.1989.021900423 http://dx.doi.org/10.1002/macp.1989.021900423

Chu F. ; Yamaoka T. ; Ide H. ; Kimura Y. Microvoid formation process during the plastic deformation of β -form polypropylene . Polymer , 1994 , 35 ( 16 ), 3442 - 3448 . doi: 10.1016/0032-3861(94)90906-7 http://dx.doi.org/10.1016/0032-3861(94)90906-7

Chu F. ; Kimura Y. Structure and gas permeability of microporous films prepared by biaxial drawing of β -form polypropylene . Polymer , 1996 , 37 ( 4 ), 573 - 579 . doi: 10.1016/0032-3861(96)83143-0 http://dx.doi.org/10.1016/0032-3861(96)83143-0

Chu F. ; Yamaoka T. ; Kimura Y. Crystal transformation and micropore formation during uniaxial drawing of β -form polypropylene film . Polymer , 1995 , 36 ( 13 ), 2523 - 2530 . doi: 10.1016/0032-3861(95)91197-f http://dx.doi.org/10.1016/0032-3861(95)91197-f

Varga J. ; Mudra I. ; Ehrenstein G. W. Crystallization and melting of β -nucleated isotactic polypropylene . J. Therm. Anal. Calorim. , 1999 , 56 ( 3 ), 1047 - 1057 . doi: 10.1023/a:1010132306934 http://dx.doi.org/10.1023/a:1010132306934

Lyu D. ; Lu Y. ; Thompson G. ; Caton-Rose F. ; Lai Y. Q. ; Coates P. ; Men Y. F. A simple way to control small-strain cavitation in die-drawn isotactic polypropylene . Ind. Eng. Chem. Res. , 2021 , 60 ( 14 ), 5151 - 5160 . doi: 10.1021/acs.iecr.1c00172 http://dx.doi.org/10.1021/acs.iecr.1c00172

Xiong B. J. ; Kang J. ; Chen R. ; Men Y. F. Initiation of cavitation upon drawing of pre-oriented polypropylene film: in situ SAXS and WAXD studies . Polymer , 2017 , 128 , 57 - 64 . doi: 10.1016/j.polymer.2017.09.017 http://dx.doi.org/10.1016/j.polymer.2017.09.017

Qian L. ; Zhang Y. ; Zhao X. T. ; Xiang M. Y. ; Lu Y. ; Men Y. F. Temperature dependency of cavitation in impact copolymer polypropylene during stretching . Polymer , 2021 , 217 , 123428 . doi: 10.1016/j.polymer.2021.123428 http://dx.doi.org/10.1016/j.polymer.2021.123428

Lu Y. ; Lyu D. ; Xiong B. J. ; Chen R. ; Men Y. F. Inter-fibrillar Tie chains determined critical stress of large strain cavitation in tensile stretched isotactic polypropylene . Polymer , 2018 , 138 , 387 - 395 . doi: 10.1016/j.polymer.2018.01.076 http://dx.doi.org/10.1016/j.polymer.2018.01.076

Zhao J. Y. ; Sun Y. Y. ; Men Y. F. Elasticity reinforcement in propylene-ethylene random copolymer stretched at elevated temperature in large deformation regime . Macromolecules , 2016 , 49 ( 2 ), 609 - 615 . doi: 10.1021/acs.macromol.5b02585 http://dx.doi.org/10.1021/acs.macromol.5b02585

Strobl G. R. The physics of polymers: concepts for understanding their structures and behavior . Berlin : Springer , 1997 . doi: 10.1524/zpch.1998.206.part_1_2.274a http://dx.doi.org/10.1524/zpch.1998.206.part_1_2.274a

Sun R. S. ; Mi R. Q. ; Luo W. ; Hu W. B. Polymer stress relaxation in biaxially stretching-induced crystallization . Polymer , 2025 , 328 , 128446 . doi: 10.1016/j.polymer.2025.128446 http://dx.doi.org/10.1016/j.polymer.2025.128446

Views

169

下载量

CSCD

Alert me when the article has been cited

提交

Tools

Publicity Resources

Disentanglement of Polylactide Melt by Oscillatory Shear Stress Field

Related Author

Tian-yu Liu

Wei-jiao Jiang

Wei-xing Yang

Qin Zhang

Qiang Fu

Related Institution

College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University

AI脑图

AI问答

Postal code：100190
Tel：010-62588927 Email：gfzxb@iccas.ac.cn
Technical support is provided by Beijing Founder electronics co., LTD 京ICP备05002797号-8 京公网安备11010802046899号
It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.

⁰