Photoswitching Behavior of SiO2Inverse Opal Films Infiltrated with Azo-Tolane Copolymer: Effect of Polymer Main Chain Structure

2009 ◽  
Vol 513 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Tomomi Shirota ◽  
Masaki Moritsugu ◽  
Shoichi Kubo ◽  
Tomonari Ogata ◽  
Takamasa Nonaka ◽  
...  
2012 ◽  
Vol 45 (9) ◽  
pp. 095201 ◽  
Author(s):  
Takuji Uesugi ◽  
Takeru Okada ◽  
Akira Wada ◽  
Keisuke Kato ◽  
Atsushi Yasuda ◽  
...  

2001 ◽  
Vol 665 ◽  
Author(s):  
Zhi-Kuan Chen ◽  
Nancy Hoi Sim Lee ◽  
Wei Huang

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.


2002 ◽  
Vol 725 ◽  
Author(s):  
Seung Koo Park ◽  
Jung Yun Do ◽  
Jung-Jin Ju ◽  
Suntak Park ◽  
Myung-Hyun Lee

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.


1995 ◽  
Vol 7 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Yoshio Imai

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.


Polymer ◽  
2014 ◽  
Vol 55 (8) ◽  
pp. 1917-1919 ◽  
Author(s):  
Masato Sakaguchi ◽  
Masakazu Makino ◽  
Takeshi Ohura ◽  
Tadahisa Iwata

1960 ◽  
Vol 33 (1) ◽  
pp. 72-77
Author(s):  
A. Mercurio ◽  
A. V. Tobolsky

Abstract Deterioration of many vulcanized hydrocarbon rubbers is known to be due to reaction with molecular oxygen. Such a process is independent of oxygen concentration down to several mm of oxygen pressure and hence proceeds quite readily in an air atmosphere provided that experiments are conducted with thin enough samples to eliminate oxygen diffusion effects. Two chemically distinct loci for attack by oxygen are available. These are the crosslinked sites which are added during the vulcanization process and the network chains which are essentially the same as in the unvulcanized material. The prime objective of this study is to show clearly that vulcanized natural rubber suffers oxidative scission predominantly along the polyisoprene chains and not at the crosslinked sites as proposed by Berry and Watson. Other literature has appeared which indicates that this important point needs further clarification. Stress relaxation experiments, which measure the rate of breaking of the weakest chemical bonds recurring throughout the structure, have been utilized. If the crosslinks are oxidized, then similar rates of scission should be obtained for different chain structures so long as the common crosslink is present in all of them. On the other hand, if chains are oxidized, then rates of scission should be essentially independent of the crosslinking agent used but rather depend markedly on each chain structure. The five chain structures used in this study are depicted in Table I. In each case at least a few per cent of double bond-containing segments are present in the main chain to allow for ordinary chemical vulcanization methods. All of these have been crosslinked by sulfur and by a nonsulfur containing agent.


2016 ◽  
Author(s):  
Jiří Vohlídal ◽  
Edward S. Wilks ◽  
Andrey Yerin ◽  
Alain Fradet ◽  
Karl-Heinz Hellwich ◽  
...  

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