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Structure evolution and properties enhancement of polyamide‐6/polyamide‐1010 films under uniaxial and biaxial stretching

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Journal of Applied Polymer Science
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Xintu Lin
Xintu Lin
Xintu Lin
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Yuejun Liu
Yuejun Liu
Yuejun Liu
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Ruijie Jin
Ruijie Jin
Ruijie Jin
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Yong Peng
Yong Peng
Yong Peng
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Abstract and Figures

The effect of stretching process on the structures and properties of the stretch‐oriented PA6/PA1010 film was investigated during the uniaxial and biaxial stretching. The results showed that the PA6/PA1010 cast film exhibited β‐form crystals, and the uniaxial stretching induced the β → α + γ phase transition and preferential orientation along the stretching direction, while the β → α phase transition and no preferential orientation were observed during the biaxial stretching process. Meanwhile, the melting temperature and crystallinity of PA6 in uniaxially and biaxially stretched PA6/PA1010 films were improved with the increasing stretching ratios, thus creating a much more tortuous pathway for the diffusion of oxygen molecules to enhance the oxygen barrier property of the stretched films after uniaxial and biaxial stretching. The morphological analysis showed that the PA1010 particles were oriented and deformed along the stretching direction and no obvious debonding and voids were observed at the interface. In addition, the mechanical properties of the stretched films were closely dependent upon the stretching ratios. It was found that the tensile strength of the biaxially stretched PA6/PA1010 films with stretching ratio of 3.5 × 3.5 in MD and TD exhibited about 1.7 times and 2.2 times higher than that of the PA6/PA1010 cast film, respectively.
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RESEARCH ARTICLE
Structure evolution and properties enhancement
of polyamide-6/polyamide-1010 films under uniaxial
and biaxial stretching
Xintu Lin
1,2
| Yuejun Liu
2
| Ruijie Jin
1
| Yong Peng
1
1
Nanchang Key Laboratory of
Photoelectric Conversion and Energy
Storage Materials, College of Science,
Nanchang Institute of Technology,
Nanchang, China
2
Key Laboratory of Advanced Packaging
Materials and Technology of Hunan
Province, School of Packaging and
Materials Engineering, Hunan University
of Technology, Zhuzhou, China
Correspondence
Yuejun Liu, Key Laboratory of Advanced
Packaging Materials and Technology of
Hunan Province, School of Packaging and
Materials Engineering, Hunan University
of Technology, Zhuzhou 412007, China.
Email: yjliu_2005@126.com
Yong Peng, Nanchang Key Laboratory of
Photoelectric Conversion and Energy
Storage Materials, College of Science,
Nanchang Institute of Technology,
Nanchang 330099, China.
Email: pengyong@nit.edu.cn
Funding information
Foundation for Innovative Research
Groups of the National Natural Science
Foundation of China, Innovative Research
Group Project of the National Natural
Science Foundation of China,
Grant/Award Number: 11872179; The
Scientific Research Project of Education
Department of Jiangxi Province,
Grant/Award Number: GJJ2201522
Abstract
The effect of stretching process on the structures and properties of the
stretch-oriented PA6/PA1010 film was investigated during the uniaxial and
biaxial stretching. The results showed that the PA6/PA1010 cast film exhib-
ited β-form crystals, and the uniaxial stretching induced the β!α+γphase
transition and preferential orientation along the stretching direction, while
the β!αphase transition and no preferential orientation were observed
during the biaxial stretching process. Meanwhile, the melting temperature
and crystallinity of PA6 in uniaxially and biaxially stretched PA6/PA1010
films were improved with the increasing stretching ratios, thus creating a
much more tortuous pathway for the diffusion of oxygen molecules to
enhance the oxygen barrier property of the stretched films after uniaxial and
biaxial stretching. The morphological analysis showed that the PA1010 parti-
cles were oriented and deformed along the stretching direction and no obvi-
ous debonding and voids were observed at the interface. In addition, the
mechanical properties of the stretched films were closely dependent upon the
stretching ratios. It was found that the tensile strength of the biaxially
stretched PA6/PA1010 films with stretching ratio of 3.5 3.5 in MD and TD
exhibited about 1.7 times and 2.2 times higher than that of the PA6/PA1010
cast film, respectively.
KEYWORDS
biaxial stretching, crystal structure, microstructure, polyamide-6, thin films
1|INTRODUCTION
Benefitting from the good printability and processibility,
superior barrier, and mechanical properties, biaxially ori-
ented polyamide-6 (BOPA) film is widely applied in multi-
product packaging, such as food, pharmaceutical products,
soft-packaged lithium-ion battery, and so on. In recent
years, with the increasing market demand for flexible
packaging due to its excellent performance and conve-
nience offered by the packages, the BOPA film industry
has developed rapidly. However, few works dealing with
this topic have been reported in the literature.
1–4
Received: 28 March 2023 Revised: 16 May 2023 Accepted: 21 May 2023
DOI: 10.1002/app.54253
J Appl Polym Sci. 2023;140:e54253. wileyonlinelibrary.com/journal/app © 2023 Wiley Periodicals LLC. 1of9
https://doi.org/10.1002/app.54253
... In the case of the heating-treated film (Figure 7a), the intensity of the diffraction ring was noticeably enhanced compared with the untreated one (Figure 5c), indicating an increase in the crystallinity of the copolymer film. With an increase in the stretching ratio, the diffraction signals in the direction of MD became stronger than those in the TD direction accompanied by the transform into non-uniform rings with the (010) and (110) lattice planes evolving from two semicircles into two shorter arcs, suggesting an increase in the crystalline orientation of the BO-PA66/PACM6 film [30,43]. When the stretching ratio was further increased to 3 × 3, the intensity of the diffraction ring was further decreased. ...
... It can be found that the melting temperature and the crystallinity of BO-PA66/PACM6 were slightly increased with the increase in the stretching ratio (Table S4) due to the more regular arrangement of the polymer chains upon stretching. and (110) lattice planes evolving from two semicircles into two shorter arcs, suggesting an increase in the crystalline orientation of the BO-PA66/PACM6 film [30,43]. When the stretching ratio was further increased to 3 × 3, the intensity of the diffraction ring was further decreased. ...
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