Zhang, Haichao published the artcileSynthesis of side chain liquid crystalline polymethacrylates containing azobenzene mesogenic groups and the effect of spacer length on their liquid crystal behavior, Synthetic Route of 135529-02-1, the publication is Gaofenzi Xuebao (1999), 100-106, database is CAplus.
A series of thermotropic side chain liquid crystalline poly[ω-(4′-methoxy-4-azophenyloxy)alkanoyl]methacrylates (PMAAZOn, n = 2, 3, 4, 5, 6) were prepared by the reaction of potassium methacrylate and 4-methoxy-4′-(1-bromoalkoxy)azobenzene, then free radical polymerization in THF solution Their structures were verified by 1H, 13C-NMR and IR spectra. The number average mol. weight ( MW ) of PMAAZOn was around 20,000, thus the effects of MW on the liquid crystalline (LC) properties were negligible. The LC behaviors of the polymers obtained were examined by DSC and optical polarizing microscope. Only one nematic state for PMAAZOn, (n = 2, 3 and 4), and two LC states, one smectic and one nematic state for the polymers of n = 5 and 6 were observed As spacer length increased, glass transition temperature decreased. On the curves of ΔH (enthalpy change) and ΔS (entropy change) against spacer length, the lowest values appeared at n = 3. The lowest stability of LC state was probably the result of odd-even effect and low decoupling. The odd-even effect on TNI (clear point) of PMAAZOn was observed, and explained based on the placement of the mesogenic groups on relation to the polymer backbone. The phys. aging process of the polymers would increase their TNI and decrease ΔHNI (enthalpy change at clear point).
Gaofenzi Xuebao published new progress about 135529-02-1. 135529-02-1 belongs to esters-buliding-blocks, auxiliary class azo,Alkenyl,Benzene,Ester,Ether, name is 6-(4-((4-Methoxyphenyl)diazenyl)phenoxy)hexyl methacrylate, and the molecular formula is C7H7IN2O, Synthetic Route of 135529-02-1.
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