scholarly journals Super-Toughed PLA Blown Film with Enhanced Gas Barrier Property Available for Packaging and Agricultural Applications

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1663 ◽  
Author(s):  
Yuanping Jiang ◽  
Cong Yan ◽  
Kai Wang ◽  
Dawei Shi ◽  
Zhengying Liu ◽  
...  

Polylactic acid (PLA) holds enormous potential as an alternative to the ubiquitous petroleum-based plastics to be used in packaging film and agricultural film. However, the poor viscoelastic behavior and its extremely low melt strength means it fails to meet the requirements in film blowing processing, which is the most efficient film processing method with the lowest costs. Also, the PLA’s brittleness and insufficient gas barrier properties also seriously limit PLA’s potential application as a common film material. Herein, special stereocomplex (SC) networks were introduced to improve the melt strength and film blowing stability of PLA; polyethylene glycol (PEG) was introduced to improve PLA’s toughness and gas barrier properties. Compared with neat poly(l-lactide) acid (PLLA), modified PLA is stable in the film blowing process and its film elongation at break increases more than 18 times and reaches over 250%, and its O2 permeability coefficient decreased by 61%. The resulting film material also has good light transmittance, which has great potential for green packaging applications, such as disposable packaging and agricultural films.

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.


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

Cellulose ◽  
2015 ◽  
Vol 22 (6) ◽  
pp. 3799-3810 ◽  
Author(s):  
Qiyang Wang ◽  
Jinghua Guo ◽  
Dingfeng Xu ◽  
Jie Cai ◽  
Yongtao Qiu ◽  
...  

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