scholarly journals Effect of Molecular Structure Modification and Nano-Doping on Charge Transportation of Polyimide Films for Winding Insulation

2020 ◽  
Author(s):  
Boxue Du ◽  
Ranran Xu ◽  
Jiwen Xing ◽  
Jin Li
Keyword(s):  
Molecular Structure ◽  
Structure Modification ◽  
Polyimide Films ◽  
Winding Insulation

scholarly journals 2D-Cross Correlation Spectroscopy Coupled with Molecular Fluorescence Spectroscopy for Analysis of Molecular Structure Modification of Camel Milk and Cow Milk Mixtures during Coagulation

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 724 ◽  
Author(s):  
Oumayma Boukria ◽  
El Mestafa El Hadrami ◽  
Shaxnoza Sultanova ◽  
Jasur Safarov ◽  
Françoise Leriche ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Fluorescence Spectroscopy ◽  
Correlation Spectroscopy ◽  
Cow Milk ◽  
Structure Modification ◽  
Casein Micelles ◽  
Molecular Fluorescence ◽  
Camel's Milk ◽  
Hydrolysis Of ◽  
Rate Of Response

Synchronous fluorescence spectroscopy (SFS) coupled with two-dimensional correlation spectroscopy (2DCOS) was employed to monitor, at the molecular level, the coagulation of five mixture ratios of camel’s milk (CaM) and cow’s milk (CM) (100% CaM, 75% CaM:25% CM, 50% CaM:50% CM, 25% CaM:75% CM and 100% CM). The dissimilarities among the different formulations are highlighted on the synchronous 2DCOS-SFS. In addition, according to the cross-peak symbols in synchronous and asynchronous spectra, the rate of response modification in riboflavin, protein and vitamin A matched with common coagulation phenomena usually reported during chymosin coagulation (hydrolysis of κ-casein, destabilization of casein micelles and aggregation). This study demonstrated that 2DCOS-SFS is a successful strategy to discriminate milk mixtures and to monitor molecular structure modifications during coagulation process.

Waxd Study of Low TCE Polyimide Films Formed from Polyamic Acid Blends and Copolymers.

1992 ◽  
Vol 264 ◽  
Author(s):  
Thomas L. Nunes ◽  
Krishna G. Sachdev
Keyword(s):  
Molecular Structure ◽  
Tensile Strength ◽  
Crystallinity Index ◽  
Moisture Uptake ◽  
Chain Segment ◽  
Polyimide Films ◽  
Flexible Chain ◽  
Polyamic Acid ◽  
Out Of Plane ◽  
Molecular Anisotropy

AbstractLow TCE polyimides, typically BPDA-PDA and related materials are well known for their special properties which include low in-plane TCE, up to 3X higher elastic modulus and ultimate tensile strength, and lower moisture uptake relative to the commonly known flexible chain polyimides [1]. These differences are due to the rod-like orientation and highly organized molecular structure of the polyimides that are derived from linear-planar precursors resulting in more anisotropic properties such as the X-Y vs Z-direction TCE [2], and optical as well as dielectric properties.In the present study, we have measured the WAXD patterns of polyimide films formed from BPDA-PDA and BTDA-PDA polyamic acid mixtures and BPDA-BTDA-PDA random copolyamic acids. In order to examine the effect of a highly flexible chain segment on the molecular anisotropy of rod-like polyimides, preliminary WAXD patterns were recorded for films of BPDA-BDAF and a BPDA-PDA-BDAF copolyimide.An in-plane and an out-of-plane crystallinity index, measures of molecular order within the polyimide films studied were estimated from the WAXD patterns. The data are correlated with the various blends and copolymer compositions and discussed in terms of structural implications.

Facile bromine-termination of nonlinear optical chromophore: remarkable optimization in photophysical properties, surface morphology and electro-optic activity

RSC Advances ◽  
2015 ◽  
Vol 5 (123) ◽  
pp. 102108-102114 ◽  
Author(s):  
Jieyun Wu ◽  
Shuhui Bo ◽  
Wen Wang ◽  
Guowei Deng ◽  
Zhen Zhen ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Surface Morphology ◽  
Nonlinear Optical ◽  
Photophysical Properties ◽  
Structure Modification ◽  
Electro Optic ◽  
Nonlinear Optical Chromophore ◽  
Macroscopic Properties

This paper describes how a small molecular structure modification can enhance the microscopic and macroscopic properties of chromophore.

Intrinsically heat-sealable polyimide films with atomic oxygen resistance: Synthesis and characterization

2020 ◽  
Vol 32 (8) ◽  
pp. 902-913 ◽  
Author(s):  
Hongjiang Ni ◽  
Yu Xing ◽  
Xiaoxiang Dai ◽  
Daijun Zhang ◽  
Jun Li ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Mechanical Property ◽  
Thermal Resistance ◽  
Mechanical Strength ◽  
Phosphine Oxide ◽  
Atomic Oxygen ◽  
Synthesis And Characterization ◽  
Polyimide Films ◽  
Diphenylphosphine Oxide ◽  
Oxide Group

Intrinsically heat-sealable polyimides with atomic oxygen (AO) resistance (ARPIs) were synthesized from 2,3,3′,4′-oxydiphthalic anhydride (aODPA), 2,5-bis[(4-aminophenoxy)phenyl]diphenylphosphine oxide (BADPO), and para-phenylenediamine (PDA). The effects of the molecular structure and diamine ratio were investigated on the properties of the ARPI, including mechanical property, thermal property, heat sealability, and AO resistance. Heat sealability and AO resistance were realized for the ARPI film by combining the asymmetry of the aODPA moiety and the passivated layer forming characteristic of diphenylphosphine phosphine oxide group. Meanwhile, the deficiency of low mechanical strength and thermal resistance, commonly existing in a completely BADPO-derived polyimide system, was remedied effectively by the higher reactivity and rigidity of PDA.

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