72108-22-6Relevant academic research and scientific papers
Preparation of 1,2-bis(4-hydroxyphenyl)-2-hydroxypropanes
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Example 1, (2008/06/13)
The present invention relates to the preparation of substituted or unsubstituted 1,2-bis(4-hydroxyphenyl)-hydroxyaliphatics such as 1,2-bis(4-hydroxyphenyl)-2-hydroxypropanes by reacting substituted or unsubstituted 1,2-bis(4-hydroxyphenyl)-halogen substituted aliphatics such as 1,2-bis(4-hydroxyphenyl)-2-chloropropanes in the presence of a base and water.
Liquid crystalline epoxy thermosets
Giamberini,Amendola,Carfagna
, p. 9 - 22 (2007/10/03)
Rigid rod epoxy compounds can be cured in liquid crystalline structure. The so obtained networks exhibit better mechanical properties with respect to the isotropic ones. The mesogenic character of the epoxy compounds appears more crucial than the molecular geometry of the curing agent in developing liquid crystallinity. The curing temperature plays an important role in affecting the state of order of the thermosets.
Synthesis and Characterization of Thermotropic Polyethers and Copolyethers Based on 4,4'-dihydroxy-α-methylstilbene and Flexible Spacers Containing Odd Numbers of Methylene Units
Percec, V.,Asami, K.,Tomazos, D.,Feijoo, J. L.,Ungar, G.,Keller, A.
, p. 47 - 66 (2007/10/02)
This paper describes the synthesis and characterization of thermotropic polyethers and copolyethers based on 4,4'-dihydroxy-α-methylstilbene (HMS) and flexible spacers containing odd number of methylene units .The polyethers HMS-X are binary copolymers containing structural units derived from the two constitutional isomers of HMS and the flexible spacer.The binary copolymers HMS-X/Y (A/B) contain four structural units derived from combinations of the two constitutional isomers of HMS and the two flexible spacers.The following polymers and copolymers were synthesized and characterized: HMS-5, HMS-7, HMS-9, HMS-11, HMS-13(A/B), HMS-5/7(A/B), HMS-5/9(A/B), HMS-5/11(A/B), HMS-7/9(A/B), HMS-9/11(A/B), and HMS-9/13(A/B).All polymers had number average molecular weights higher than 15,000 and exhibited an enantiotropic nematic mesophase and several crystalline phases.Both the crystalline and the liquid crystalline phases are kinetically controlled i.e., their thermal transition temperatures and associated enthalpy changes are dependent on the heating rate and thermal history of the sample.These results led to the conclusion that for high molecular weight semi-flexible liquid crystalline polymers non-equilibrium states exist both in the liquid crystalline and crystalline phases.Quasi-equilibrium nematic-isotropic transition temperatures and enthalpy changes were obtained either from the first heating scan or after suitable annealing of the polymer sample.
Diacetylenic Liquid Crystalline Polymers II: Derivatives of 10,12-Docosadiyne-1,22-Dioic Acid
Ozcayir, Y.,Asrar, J.,Clough, S. B.,Blumstein, A.
, p. 167 - 178 (2007/10/02)
Polymers of 10,12-docosadiyne-1,22-dioic acid with different mesogenic groups have been prepared.The mesogenic groups were diphenyl (Polymer I); p-diphenylazoxy (Polymer II); 2,2'-dimethyldiphenylazoxy (Polymer III); 2-methyldiphenylazomethine (Polymer IV) and α-methylstilbene (Polymer V).All polymers crystallized extensively at room temperature, but only polymers I and V displayed an enantiotropic smectic mesophase.The X-ray diffractograms were consistent with a smectic H mesophase for both polymers.Polymers I and V differed also from polymers II-IV by enhanced reactivity of the diacetylenic moiety.A model for chain packing consistent with the X-ray diffraction pattern of the crystalline and the smectic phase is proposed.Keywords: diacetylenic polyesters, synthesis of, liquid crystalline order
