Effect of processing and thickness on the structure in a polyimide film of poly(pyromellitic dianhydride-oxydianiline)

1997 ◽  
Vol 37 (7) ◽  
pp. 1195-1209 ◽  
Author(s):  
Ravi F. Saraf
Keyword(s):  
Polyimide Film ◽  
Pyromellitic Dianhydride

Characterization and Thermal Degradation of Polyimide Derived from 5-amino-2(p-aminophenyl) Benzoxazole Monomer with Pyromellitic Dianhydride

2012 ◽  
Vol 455-456 ◽  
pp. 806-814 ◽  
Author(s):  
Xiang Li Meng ◽  
Ling Jiang ◽  
Yu Dong Huang
Keyword(s):  
Thermal Degradation ◽  
Three Dimensional ◽  
Integral Form ◽  
Polyimide Film ◽  
Amic Acid ◽  
Pyromellitic Dianhydride ◽  
Ozawa Method ◽  
Element Analysis ◽  
Exponential Factor ◽  
Good Thermal Stability

- 5-amino-2(p-aminophenyl) benzoxazole (AAPB) and its derived polyimide prepared with pyromellitic dianhydride (PMDA) were synthesized successfully. Their structures were characterized by FT-IR, 1H NMR, Element analysis, 13C NMR, Solid-state 13CNMR, DSC, TG and XRD. The polyimide was synthesized via a conventional two-stage method. The intermediate poly (amic acid) had inherent viscosity of 1.06dL/g and could be thermally converted into light yellow polyimide film. The polyimide showed excellent solvent resistance and good thermal stability. The glass transition temperature (Tg) was found to be 314°C, the decomposition started at a temperature above 500°C in air and above 550°C in argon atmosphere. The thermal degradation of the polyimide was studied by thermogravimetric analysis (TGA) in order to determine the actual reaction mechanisms of the decomposition process. The apparent activation energy (Ea) was obtained following Flynn-Wall-Ozawa method. The activation energies of different mechanism models and pre-exponential factor (A) were determined by Coats-Redfern method. Compared with the value obtained from the Ozawa method, the actual reaction mechanism obeyed three-dimensional diffusion model, Jander equation (D3) with integral form g(α)=[1-(1-α)1/3]2.

scholarly journals Design, Fabrication, and Testing of a Novel 3D 3-Fingered Electrothermal Microgripper with Multiple Degrees of Freedom

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 444
Author(s):  
Guoning Si ◽  
Liangying Sun ◽  
Zhuo Zhang ◽  
Xuping Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Polyimide Film ◽  
Zebrafish Embryos ◽  
Multiple Degrees Of Freedom ◽  
Electrothermal Actuator ◽  
3D Space ◽  
Pick And Place

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.

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.

Elucidation of the thickness inside the niobium anodic oxide film and its effect on adhesion to polyimide film

Vacuum ◽  
2021 ◽  
pp. 110265
Author(s):  
Munenori Yoshida ◽  
Hiromi Yamanaka ◽  
Kenta Tomori ◽  
Sergei Kulinich ◽  
Syuuichi Maeda ◽  
...  
Keyword(s):  
Oxide Film ◽  
Anodic Oxide ◽  
Polyimide Film ◽  
Anodic Oxide Film

Study on the high frequency insulation strength of disiloxane modified polyimide film

2020 ◽  
Author(s):  
Chong Zhang ◽  
Zhaoliang Xing ◽  
Pengfei Wu ◽  
Xiying Dai ◽  
Zhiyun Han ◽  
...  
Keyword(s):  
High Frequency ◽  
Polyimide Film
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