Novel copolyhydrazides and copolyoxadiazoles based on 1,4-phenyl linkage and 1,3,4-thiadiazole moiety in the polymer Main chain to induce glass transition and to improve the thermal stability, solubility, and antimicrobial activity

2019 ◽  
Vol 26 (2) ◽  
Author(s):  
Kamal I. Aly ◽  
Osama Younis ◽  
Nayef S. Al-Muaikel ◽  
Ahmed A. Atalla ◽  
Abu-Bakr A. A. M. El-Adasy ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Antimicrobial Activity ◽  
Glass Transition ◽  
Main Chain ◽  
Polymer Main Chain

Synthesis and Characterization of Low Content of Structural Defects of Aryl-Substituted Electroluminescent Poly(p-phenylenevinylene)s

2001 ◽  
Vol 665 ◽  
Author(s):  
Zhi-Kuan Chen ◽  
Nancy Hoi Sim Lee ◽  
Wei Huang
Keyword(s):  
Thermal Stability ◽  
Quantum Efficiency ◽  
Defect Structure ◽  
Main Chain ◽  
Structural Defects ◽  
Synthesis And Characterization ◽  
Good Thermal Stability ◽  
H Nmr ◽  
Polymer Main Chain

ABSTRACTWe report the synthesis and characterization of a novel series of aryl-substituted PPVs, which have shown excellent processability, good thermal stability, high photoluminescence quantum efficiency and low content of structural defects. The substituents of the polymers were designed with different degree of hindrance effect on the main chain. 1H NMR measurement indicates that the defect structure in the polymer main chain can be effectively depressed by introducing bulk and hindrance substituents.

New Host-Guest Polymeric System for Thermal Stability Enhancement of Electro Optic Effect

2002 ◽  
Vol 725 ◽  
Author(s):  
Seung Koo Park ◽  
Jung Yun Do ◽  
Jung-Jin Ju ◽  
Suntak Park ◽  
Myung-Hyun Lee
Keyword(s):  
Thermal Stability ◽  
Model Compound ◽  
Main Chain ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
New Host ◽  
Polymer Main Chain ◽  
Electro Optic ◽  
Chromophore Concentration ◽  
Stability Enhancement

AbstractA new host-guest electro optic (EO) polymer, in which a chromophore can be reacted with the polymer main chain during poling to give the corresponding side-chain EO polymer, has been prepared for improving EO effect and its thermal stability. Polyisoimide (PII) synthesized from 2, 2-bis (4-aminophenyl) hexafluoropropane and oxydiphthalic anhydride and Disperse Red 1 (DR1) were used as a host and a guest, respectively. A model compound reaction and Infrared spectra of the host-guest film after annealing at various temperatures show that the reaction between the isoimide groups in PII and the hydroxyl groups in DR1 occurs around 140 °C. The glass transition temperatures of the resulting EO polyamic aicd ester-imide copolymer with 0, 10, 20 and 30 wt. % of chromophore concentration were 275, 219, 160, and 124 °C, respectively. The EO coefficient obtained at a wavelength of 1.55 νm was 5.3 and 10.5 pm/V from the EO polymer film with 20 and 30 wt. % DR1. The EO signals exhibited only a slight decay at high temperature due to the chemical reaction between the host and guest during poling.

Novel polyhydrazides and polyoxadiazoles based on 1,3,4‐thiadiazole moiety in the main chain with high thermal stability, good solubility, and notable antimicrobial activity

2019 ◽  
Vol 136 (28) ◽  
pp. 47770 ◽  
Author(s):  
Kamal I. Aly ◽  
Osama Younis ◽  
Nayef S. Al‐Muaikel ◽  
Ahmed A. Atalla ◽  
Abu‐Bakr A. A. M. El‐Adasy ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Antimicrobial Activity ◽  
Main Chain ◽  
High Thermal Stability ◽  
Good Solubility

Synthesis of novel organic-soluble high-temperature aromatic polymers

1995 ◽  
Vol 7 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Yoshio Imai
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Main Chain ◽  
Phenyl Group ◽  
Current Work ◽  
Transition Temperatures ◽  
Polymer Backbone ◽  
Glass Transition Temperatures ◽  
Aromatic Polyamides ◽  
Polymer Main Chain

This paper reviews our current work on the synthesis of new organic-soluble aromatic polyamides and polyimides having high glass transition temperatures above 300 °C. Our strategy to achieve this goal is to introduce a bulky pendant phenyl group along the polymer backbone and to incorporate a crank and twisted non-coplanar structure into the polymer main chain.

Polyimides Containing 1,3,4-Oxadiazole Rings

2008 ◽  
Vol 73 (12) ◽  
pp. 1631-1644 ◽  
Author(s):  
Maria Bruma ◽  
Mariana-Dana Damaceanu
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Main Chain ◽  
The Other ◽  
Carbonyl Groups ◽  
Aromatic Diamines ◽  
Film Forming ◽  
As Solubility

Two series of polyimides containing 1,3,4-oxadiazole rings in the main chain, one of them having flexible hexafluoropropane-2,2-diyl groups and the other with carbonyl groups, were prepared by polycondensation of aromatic diamines containing 1,3,4-oxadiazole rings with hexafluoropropane-2,2-diyl-bis(phthalic anhydride) or benzophenonetetracarboxylic dianhydride. Their properties, such as solubility in organic solvents, thermal stability, glass transition temperature, photoluminescence and film-forming properties of the two groups of polymers have been studied and compared.

Investigating the role of GeO2 in enhancing the thermal stability and proton mobility of proton-conducting phosphate glasses

2021 ◽  
Author(s):  
Takahisa Omata ◽  
Aman Sharma ◽  
Takuya Kinoshita ◽  
Issei Suzuki ◽  
Tomohiro Ishiyama ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Phosphate Glasses ◽  
Proton Mobility ◽  
Proton Conducting

In this study, the effect of GeO2 on the thermal stability and proton mobility (μH) of proton-conducting phosphate glasses was experimentally investigated using 22HO1/2−3NaO1/2−(12−x)LaO3/2−xGeO2−63PO5/2 glasses. Increasing glass transition temperature (Tg)...

The effect of methyl and methoxy substituents on dianilines for a thermosetting polyimide system

2020 ◽  
Vol 32 (7) ◽  
pp. 801-822 ◽  
Author(s):  
John J La Scala ◽  
Greg Yandek ◽  
Jason Lamb ◽  
Craig M Paquette ◽  
William S Eck ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Glass Transition ◽  
Elevated Temperature ◽  
Methyl Substituent ◽  
Glass Transition Temperatures ◽  
High Performing ◽  
Methoxy Substituent ◽  
Acidic Conditions ◽  
Thermal Stability Of

4,4′-Methylenedianiline (MDA) is widely used in high-temperature polyimide resins, including polymerization of monomer reactants-15. The toxicity of MDA significantly limits the manufacturability using this resin. Modifying the substitution and electronics of MDA could allow for the reduction of toxicity while maintaining the high-performing properties of the materials derived from the modified MDA. The addition of a single methyl substituent, methoxy substituent, location of these substituents, and location of the amine relative to the phenolic bridge were modified as were other non-aniline diamines. Various anilines were condensed with paraformaldehyde under acidic conditions to yield dianilines. These dianilines and diamines were reacted with nadic anhydride and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in methanol to form the polyamic acid oligomers and heated at elevated temperature to form polyimide oligomers. It was found that the molecular weight of the oligomers derived from MDA alternatives was generally lower than that of MDA oligomers resulting in lower glass transition temperatures ( T gs) and degradation temperatures. Additionally, methoxy substituents further reduce the T g of the polymers versus methyl substituents and reduce the thermal stability of the resin. Methyl-substituted alternatives produced polyimides with similar T gs and degradation temperatures. The toxicity of the MDA alternatives was examined. Although a few were identified with reduced toxicities, the alternatives with properties similar to that of MDA also had high toxicities.

A Study of the Nitrogen-Containing Heterocycles on Copolyimide Properties for Proton Exchange Membranes

2013 ◽  
Vol 401-403 ◽  
pp. 563-566 ◽  
Author(s):  
Yu Han Li ◽  
Wei Jian Wang ◽  
Yu Fei Chen ◽  
Lei Wang
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Proton Conductivity ◽  
Water Uptake ◽  
Main Chain ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Membrane Properties ◽  
Dimensional Changes ◽  
Sulfonated Polyimide

Containing pyrimidine and pyridine monomers were incorporated respectively into the main chain of a sulfonated polyimide in order to investigate the effect of nitrogen-containing heterocycles on membrane properties such as water uptake and proton conductivity. With increasing content of the nitrogen-containing heterocycles, water uptake of membranes and dimensional changes remarkable decrease. The copolymer showed higher thermal stability (desulfonation temperature up to 330 °C) and reasonable good mechanical properties. These membranes also showed higher proton conductivity, which was comparable or even higher than Nafion 117.

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