Programmable Chromism and Photoluminescence of Spiropyran‐based Liquid Crystalline Polymer with Tunable Glass Transition Temperature

2021 ◽  
Author(s):  
Wei Hu ◽  
Chang Sun ◽  
Yunxiao Ren ◽  
Shengyu Qin ◽  
Yu Shao ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer

Synthesis and phase behavior of a new 2-vinylbiphenyl-based mesogen-jacketed liquid crystalline polymer with a high glass transition temperature and low threshold molecular weight

2014 ◽  
Vol 5 (15) ◽  
pp. 4526-4533 ◽  
Author(s):  
Qi-Kai Zhang ◽  
Hai-Jian Tian ◽  
Chang-Feng Li ◽  
Yu-Feng Zhu ◽  
Yongri Liang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Phase Behavior ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
High Glass Transition Temperature ◽  
Low Threshold

A new mesogen-jacketed liquid crystalline (LC) polymer was synthesized by NMP. It has a high Tg and a relatively low threshold MW for LC formation.

Preparation and characterization of post-derivatives from functional polystyrene (ATRP) with p-nitroanilineazomethine phenol and their thermal and optical study

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Xifei Yu ◽  
Guo Zhang ◽  
Tongfei Shi ◽  
P.K. Dutta ◽  
Lijia An
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Liquid Crystalline ◽  
Gel Permeation Chromatography ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
Xrd Study ◽  
Covalently Linked

AbstractThe functional polystyrene, (Cl-PS)2-CHCOOCH2CH2OH (designated as XPSt and coded P2) was prepared by ATRP at 1300C using CuCl and bipyridine as catalysts, 2,2-dichloro acetate-ethylene glycol (DCAG) as multifunctional initiator and THF as solvent. 4-Nitoroaniline azomethine-4’ phenol (P1) as chromophores were covalently linked to the functional end groups of the polymer by using simple displacement reaction. The functional polystyrenes, namely XPSt (P2) and (PS)2-CHCOOCH2CH2OH, designated as X-PSt and coded P3 and their post-derivatives, namely, DXPSt (P4) and DX-PSt (P5) respectively were characterized by IR, NMR and UV spectroscopies, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), polarising optical microscopy (POM) and XRD studies. DSC showed that incorporation of chromophores in the side chains of polymers towards the polystyrene moiety increases the rigidity of the polymer and subsequently, its glass transition temperature; however the incorporation of side chain towards the alcoholic functional group decreases the glass transition temperature. The post derivatives do not play any significant role to increase the thermal stability (TGA). There was evidence for liquid crystalline properties in the resulting polymer derivative DXPSt (P4) as observed from POM study, which defines the alignment of chromophores into the polymers. The XRD study shows crystalline behaviour of the polymer derivative, P4. The polymer derivative, DXPSt (P5) does not show such behaviour and this may be due to the bonding of azomethine towards the short chain alcoholic telechelic alcoholic sides of the copolymer.

Curing, Thermal and Mechanical Properties of Liquid Crystalline p-SBPEPB/BPAER/DDE System

2011 ◽  
Vol 239-242 ◽  
pp. 3253-3256 ◽  
Author(s):  
Li Huo ◽  
Jun Gang Gao ◽  
Yong Gang Du
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Impact Strength ◽  
Bisphenol A ◽  
Liquid Crystalline ◽  
Curing Agent ◽  
Thermal And Mechanical Properties ◽  
Component System

The curing, thermal and mechanical properties of bi-component system for bisphenol A epoxy resin (BPAER) modified by liquid crystalline Sulfonyl bis(4,1-phenylene)bis[4-(2,3-epoxypro pyloxy)benzoate] (p-SBPEPB), with 4,4'-diaminodiphenyl ether (DDE) as a curing agent, were investigated. The effect of the different liquid crystalline contents and the heating rate on curing reaction was discussed. The results show that the curing peak temperature decreases, curing rate increases, the glass transition temperature (Tg)and impact strength all increase with adding of liquid crystalline p-SBPEPB when the content is not over 8wt%.

Investigation of thermochromism in a series of side-chain, liquid-crystalline, azobenzene-containing polymers

2004 ◽  
Vol 82 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Stephan Freiberg ◽  
François Lagugné-Labarthet ◽  
Paul Rochon ◽  
Almeria Natansohn
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Liquid Crystalline ◽  
Electronic Absorption Spectra ◽  
Side Chain ◽  
Hypsochromic Shift ◽  
Vis Spectroscopy ◽  
Thermochromic Properties

The thermochromic properties of a series of liquid crystalline polymethacrylates, containing azobenzene side-chains with variable spacer lengths, were investigated. Annealing the amorphous polymer thin films above the glass transition temperature results in a rearrangement of the azobenzene moieties, causing a hypsochromic shift in the electronic absorption spectra. A detailed investigation of the spectral shift was performed by in situ UV–vis spectroscopy and indicated the formation of H-type aggregates by the side-chain chromophores above the glass transition temperature. The rate at which the hypsochromic shift occurs is faster for polymers with shorter spacers since their high glass transition temperature results in a higher thermal energy during the thermochromic effect. Experimentally determined activation energies show that the aggregation occurs primarily due to side-chain relaxation (β-relaxation) and main-chain relaxation (α-relaxation). Further annealing above the isotropization temperature resulted in the onset of deaggregation and in most cases showed that the chromophores were freed from the ordered state.Key words: liquid-crystalline polymer, thermochromic properties, chain relaxation, aggregation, thin films, azobenzene mesogens.

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