scholarly journals Advanced anticorrosive coatings prepared from electroactive polyimide/graphene nanocomposites with synergistic effects of redox catalytic capability and gas barrier properties

2014 ◽  
Vol 8 (4) ◽  
pp. 243-255 ◽  
Author(s):  
K. C. Chang ◽  
C. H. Hsu ◽  
H. I. Lu ◽  
W. F. Ji ◽  
C. H. Chang ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Barrier Properties ◽  
Gas Barrier ◽  
Graphene Nanocomposites ◽  
Anticorrosive Coatings ◽  
Gas Barrier Properties

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 ◽  
...  
Keyword(s):  
Transmission Rate ◽  
Barrier Properties ◽  
Polyimide Film ◽  
Flexible Display ◽  
Gas Barrier ◽  
Positron Annihilation Lifetime ◽  
Barrier Materials ◽  
Oxygen Transmission Rate ◽  
Display Technology ◽  
Gas Barrier Properties

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.

Tailoring morphology to improve the gas-barrier properties of thermoplastic polyurethane/ethylene-vinyl alcohol blends

2016 ◽  
Vol 56 (8) ◽  
pp. 922-931 ◽  
Author(s):  
Xiumei Gao ◽  
Dekun Sheng ◽  
Xiangdong Liu ◽  
Tongbing Li ◽  
Fance Ji ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Thermoplastic Polyurethane ◽  
Barrier Properties ◽  
Gas Barrier ◽  
Ethylene Vinyl Alcohol ◽  
Gas Barrier Properties
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