New Polymer Syntheses. 95. Photosetting Cholesteric Polyesters Derived from 4-Hydroxycinnamic Acid and Isosorbide

Abstract

Two dicarboxylic acids were prepared by alkylation of 4-hydroxycinammic acid with 1,6-dibromohexane or 1,12-dibromododecane. The dichlorides of these dicarboxylic acids were polycondensed with mixtures of isosorbide and methylhydroquinone. All copolyesters then obtained showed nematic schlieren textures. Furthermore, three dicarboxylic acids were synthezised by alkylation of 4-hydroxycinammic acid with the ditosylates of di-, tri-, and tetraethylene glycol. Numerous copolyesters were prepared from the dicarboxylic acids and mixtures of isosorbide with methyl-, tert-butyl-, or phenylhydroquinone. Also 2,7-dihydroxynaphthalene was used as a comonomer. Almost all resulting copolyesters were cholesteric, and nearly 50% of them were capable of forming a Grandjean texture. The photochemical behavior of selected copolyesters was studied in solution in spin-coated films and in films with Grandjean texture. Depending on the reaction conditions, photo-cross-linking by 2 + 2 cycloaddition competed more or less successfully with the photo-Fries rearrangement and with the photoisomerization. UV irradiation (at 313 nm) of oriented films in the cholesteric melt caused disappearance of the Grandjean texture. However, irradiation below the glass-transition temperature caused stabilization of the Grandjean texture by photo-cross-linking.

Chemo-enzymatic Synthesis, Derivatizations, and Polymerizations of Renewable Phenolic Monomers Derived from Ferulic Acid and Biobased Polyols: An Access to Sustainable Copolyesters, Poly(ester-urethane)s, and Poly(ester-alkenamer)s

“…Other homo-and copolyesters of natural p-hydroxycinnamic acids showing remarkable liquid-crystal (28)(29)(30)(31)(32)(33)(34)(35), biodegradability (36,37) or biocompatibility (30) properties were also reported. However, they are often hard to process because of a too high melting temperature (T m ).…”

Side‐chain copolymers containing smectic monomer and chiral reagent—Synthesis and characterization

“…[21][22][23] The most common chiral agent so far considered for the synthesis of chiral side-chain LC polymers are cholesterol, menthol, acid with chiral group, and so on, while isosorbide has been much used for the synthesis of chiral mainchain LC polymers and little used for the synthesis of chiral side-chain LC polymers. 13 Therefore, it has been necessary to synthesize various kinds of sidechain chiral LC containing isosorbide to study the relationship between structure and properties and then explore their potential application. And at the same time, the synthesis of lower T g cholesteric polymers was the aim of research, which offered the ability of application.…”

Effect of the length of the carbochain on the phase behavior of side‐chain cholesteric liquid‐crystalline elastomers

“…The reason we chose isosorbide as the chiral material is that it possesses a high twisting power, and obviously, a high molar fraction of isosorbide generates helixes with a pitch that is too small (or large) for an interaction with visible light. 18 The mesomorphic properties of the monomers and elastomers obtained were characterized by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and thermogravimetric analysis (TGA). The influence of the length of the carbochain on the phase behavior of the elastomers was investigated.…”