scholarly journals Impact of Backbone Amide Substitution at the Meta- and Para-Positions on the Gas Barrier Properties of Polyimide

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2097
Author(s):  
Qian Wen ◽  
Ao Tang ◽  
Chengliang Chen ◽  
Yiwu Liu ◽  
Chunguang Xiao ◽  
...  

This study designed and synthesised a meta-amide-substituted dianiline monomer (m-DABA) as a stereoisomer of DABA, a previously investigated para-amide-substituted dianiline monomer. This new monomer was polymerised with pyromellitic dianhydride (PMDA) to prepare a polyimide film (m-DABPI) in a process similar to that employed in a previous study. The relationship between the substitution positions on the monomer and the gas barrier properties of the polyimide film was investigated via molecular simulation, wide-angle X-ray diffraction (WXRD), and positron annihilation lifetime spectroscopy (PALS) to gain deeper insights into the gas barrier mechanism. The results showed that compared with the para-substituted DABPI, the m-DABPI exhibited better gas barrier properties, with a water vapour transmission rate (WVTR) and an oxygen transmission rate (OTR) as low as 2.8 g·m−2·d−1 and 3.3 cm3·m−2·d−1, respectively. This was because the meta-linked polyimide molecular chains were more tightly packed, leading to a smaller free volume and lower molecular chain mobility. These properties are not conducive to the permeation of small molecules into the film; thus, the gas barrier properties were improved. The findings have significant implications for the structural design of high-barrier materials and could promote the development of flexible display technology.

2015 ◽  
Vol 15 (10) ◽  
pp. 8348-8352 ◽  
Author(s):  
Min Eui Lee ◽  
Hyoung-Joon Jin

Poly(vinyl alcohol) (PVA) composites containing graphene oxide (GO) functionalized with PVA were synthesized via the esterification of the carboxylic groups of GO. The presence of PVA-grafted GO (PVA-g-GO) in the PVA matrix induced strong interactions between the chains of the PVA matrix and allowed the PVA-g-GO to be uniformly dispersed throughout the matrix. The grafting of PVA to GO increased the gas barrier properties of the GO/PVA composites because of the increased compatibility between GO and PVA. The PVA-g-GO/PVA composites were used to coat the surface of poly(ethylene terephthalate) films. These coated films exhibited excellent gas barrier properties; the film containing 0.3 wt% of PVA-g-GO had an oxygen transmission rate (OTR) of 0.025 cc/(m2 · day) and an optical transmittance of 83.8%. As a result, PVA-g-GO/PVA composites that exhibited enhanced gas barrier properties were prepared with a solution mixing method.


2016 ◽  
Vol 718 ◽  
pp. 10-14 ◽  
Author(s):  
Chuenkhwan Tipachan ◽  
Somjai Kajorncheappunngam

Nanocomposite films based on poly (lactic) acid (PLA) and organically nanoclay Perkalite were prepared by solvent casting method. The incorporation of Perkalite clay in PLA film was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. Morphology of PLA/Perkalite film was investigated using scanning electron microscope (SEM). The gas barrier properties of PLA nanocomposite films were determined through oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) measurement. Results from FTIR analysis indicates that Perkalite clay was incorporated in PLA film. SEM images show that dispersion of Perkalite particle on the PLA matrix was good with the additional of clay up to 3 pph (parts of clay per hundred part of PLA). The maximum reduction in OTR and WVTR of that nanocomposite film with Perkalite loading of 3 pph are 76% and 37%, respectively compared with neat PLA film. This proves that gas barrier property of PLA film is improved significantly with incorporation of Perkalite clay. The PLA/Perkalite nanocomposite film is a promising as green based packaging materials.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1402
Author(s):  
Yi Zeng ◽  
Yiwu Liu ◽  
Jinghua Tan ◽  
Jie Huang ◽  
Junjie Liu ◽  
...  

In order to meet the increasingly stringent requirements for heat resistance and barrier properties in the packaging and electronic device encapsulation field. A high-barrier polyimide (NAPPI) contains naphthalene ring and amide group was prepared by polymerization of a novel diamine (NAPDA) and pyromellitic dianhydride. The structure and properties of diamine monomers and polymers were characterized. Results show that the NAPPI exhibits superior barrier properties with extremely low water vapor and oxygen transmission rate values of 0.14 g·m−2·day−1 and 0.04 cm3·m−2·day−1, respectively. In addition, the NAPPI presents outstanding mechanical properties and thermal stability as well. This article attempts to explore the relationship between NAPPI structure and barrier properties by combining experiment and simulation. Studies on positron annihilation lifetime spectroscopy, Wide angle X-ray diffractograms and molecular dynamics simulations prove that the NAPPI has smaller interplanar spacing and higher chain regularity. In addition, the strong chain rigidity and interchain cohesion of NAPPI due to the presence of the rigid naphthalene ring and a large number of hydrogen bond interactions formed by amide groups result in compact chain packing and smaller free volume, which reduces the solubility and diffusibility of small molecules in the matrix. In general, the simulation results are consistent with the experimental results, which are important for understanding the barrier mechanism of NAPPI.


Holzforschung ◽  
2013 ◽  
Vol 67 (8) ◽  
pp. 899-905 ◽  
Author(s):  
Eva-Lena Hult ◽  
Klaus Koivu ◽  
Janne Asikkala ◽  
Jarmo Ropponen ◽  
Pauli Wrigstedt ◽  
...  

Abstract Lignin, esterified with palmitic and lauric acid chloride, has been studied for the application as coating on fiber-based packaging material. The aim was to improve the barrier properties against water vapor and oxygen of paperboard. The esterification was followed by Fourier transform infrared spectroscopy, 31P nuclear magnetic resonance spectroscopy, and gel permeation chromatography measurements. The lignin esters were applied on paperboard and formed a continuous film. The moisture barrier property of the coated paperboards was characterized by the water vapor transmission rate (WVTR). A significant decrease in WVTR was observed, for example, 40 g m-2 (for 24 h) for a paperboard coated with 10.4 g m-2 hardwood kraft lignin palmitate. The contact angle of water on the lignin ester coatings was high and stable. For all paperboard samples coated with lignin esters, a significant decrease in oxygen transmission rate was observed. Accordingly, lignin palmitate and laurate have a high potential as a barrier materials in packaging applications.


2017 ◽  
Vol 89 (12) ◽  
pp. 1841-1848 ◽  
Author(s):  
Gülsah Keskin ◽  
Gülnur Kızıl ◽  
Mikhael Bechelany ◽  
Céline Pochat-Bohatier ◽  
Mualla Öner

Abstract Today, there is an increasing concern about protection of ecological systems. Petro-based synthetic polymers are not biodegradable and cause environmental pollution. These polymers that are stuck in nature, affect wildlife adversely. Also, in future petrochemical materials will drain away and demand for eco-friendly plastics which can substitute synthetic plastics will increase. Biopolymers are products which can be degraded by enzymatic activities of various microorganisms, and the degradation products are nontoxic. They are attractive alternatives to non-degradable materials in short-term applications such as packaging. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a member of polyhydroxyalkanoate (PHA) family which is biodegradable and produced by microorganism. It has good gas barrier properties that make it convenient to use in different applications. The present paper gives an overview on PHAs and their composites, their main properties, with a specific focus on potential applications of PHBV in packaging.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2048
Author(s):  
Yiwu Liu ◽  
Ao Tang ◽  
Jinghua Tan ◽  
Xianqing Zhao ◽  
Chengliang Chen ◽  
...  

A high-barrier polyimide (2,7-CPI) was synthesized through the polymerization of pyromellitic dianhydride (PMDA) and a novel diamine (2,7-CDA) containing carbazole moiety. The synthesized diamine and polyimide were fully characterized by elemental analyses, FTIR and NMR. The 2,7-CPI displays very attractive barrier performances, with oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) low to 0.14 cm3·m−2·day−1 and 0.05 g·m−2·day−1, respectively. Meanwhile, 2,7-CPI also exhibits exceptional thermal stability with a glass transition temperature (Tg) of 467 °C, 5% weight-loss temperature (Td5%) of 550 °C under N2 and coefficient of thermal expansion (CTE) of 3.4 ppm/K. The barrier performances of 2,7-CPI are compared with those of a structural analogue (2,7-CPPI) and a typical polyimide (Kapton). Their barrier performances with respect to microstructure were investigated by molecular simulations, wide angle X-ray diffraction (WAXD), and positron annihilation lifetime spectroscopy (PALS). The results show that 2,7-CPI possesses better coplanar structure and more number of intermolecular hydrogen bonds among the three PIs, which result in tight chain packing and thereby high crystallinity, low free volume, and decreased chains mobility. That is, the high crystallinity and low free volume of 2,7-CPI reduce the diffusion and solubility of gases. Meanwhile, the poor chains mobility further decreases the gases diffusion. The reduced diffusion and solubility of gases consequently promote the improvement of barrier properties for 2,7-CPI. The polyimide has a wide application prospect in the field of flexible electronic packaging industries.


2007 ◽  
Vol 353-358 ◽  
pp. 1879-1882 ◽  
Author(s):  
Riichi Murakami ◽  
Katsuhiro Fujikawa ◽  
Daisuke Yonekura

Stainless steel is widely used as a corrosion-resistant material. However, stainless steel corrodes at high temperature (573 K ~) due to the oxidization and grain boundary corrosion. To delay the oxidation at high temperature, coating of gas barrier film will be useful method. The purpose of this study is to improve the corrosion-resistant of SUS304 at high temperature by coating transparent SiOxNy film which has gas barrier properties. In addition, the influence of inlet gas mass flow rate ratio (N2/Ar+N2) on the oxidation properties at 773 K was examined. The SiOxNy films were deposited onto polished SUS304 by unbalanced dc magnetron sputtering apparatus. To examine the oxygen transmission rate (OTR) of SiOxNy films, PET was also used as substrate. The results showed that good OTR was obtained for N2/Ar+N2 < 0.12 on PET substrate. The similar tendency was obtained for SUS304 deposited film heated up to 773 K.


2016 ◽  
Vol 56 (8) ◽  
pp. 922-931 ◽  
Author(s):  
Xiumei Gao ◽  
Dekun Sheng ◽  
Xiangdong Liu ◽  
Tongbing Li ◽  
Fance Ji ◽  
...  

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