Liquid crystalline and photocrosslinkable poly(4,4′-stilbeneoxy) alkylarylphosphates

Three series of liquid crystalline and photocrosslinkable poly(4,4′-stilbeneoxy) alkylarylphosphates were synthesized from various 4,4′-bis(m-hydroxyalkyloxy)stilbenes (m = 2, 4, 6, 8, 10) and arylphosphorodichloridates in chloroform by solution polycondensation method. Polarized optical microscope (POM) and differential scanning calorimetry (DSC) observations revealed that polymers containing less than four methylene spacer groups did not exhibit liquid crystalline (LC) texture, possibly due to smaller microdomain and restricted movement of the mesogen. In contrast, polymers containing more than four methylene spacer group established LC texture, which has been attributed to the larger monodomain and free movement of mesogens. Thermogravimetric analysis (TGA) data indicated that thermal stability and char yield decreased with increasing flexible methylene spacer groups, increased significantly for biphenyloxy and 1-naphthyloxy containing polymers than that of phenyloxy containing polymers ascribed to increasing aromaticity, size, and number of aromatic rings. Photocrosslinking of stilbene containing polymers has been shown to proceed via 2π-2π cycloaddition reaction by Ultra-violet (UV) and fluorescence. The rate photocrosslinking has been found to increase with increasing number of methylene group in the main chain. The aromaticity of the side chain also increases the rate of crosslinking. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

[1]  Tăchiță Vlad‐Bubulac,et al.  Synthesis and properties of new aromatic copolyesters containing phosphorous cyclic bulky groups , 2010 .

[2]  P. Kannan,et al.  Stilbene-based liquid crystalline and photocrosslinkable polynaphthylphosphate esters , 2010 .

[3]  Kai Xu,et al.  Preparation and properties of novel phosphorus-containing binaphthyl epoxy polymer , 2009 .

[4]  Lei Song,et al.  Flammability and thermal degradation of epoxy acrylate modified with phosphorus‐containing compounds , 2009 .

[5]  P. Kannan,et al.  Liquid crystalline and photoactive poly[4,4′-stilbeneoxy]alkylbiphenylphosphates , 2008 .

[6]  M. Engelhard,et al.  Effect of nitrogen additives on flame retardant action of tributyl phosphate: Phosphorus–nitrogen synergism , 2008 .

[7]  J. Canadell,et al.  Phosphorus-containing thermosets obtained by cationic copolymerisation of glycidyl compounds with a spiroorthoester or γ-butyrolactone , 2008 .

[8]  S. Bourbigot,et al.  Neutralized flame retardant phosphorus agent: Facile synthesis, reaction to fire in PP and synergy with zinc borate , 2008 .

[9]  C. Grimm,et al.  Epoxy Phosphonate Crosslinkers for Providing Flame Resistance to Cotton Textiles , 2007 .

[10]  G. Ruggeri,et al.  Bis(benzoxazolyl)stilbene excimers as temperature and deformation sensors for biodegradable poly(1,4-butylene succinate) films , 2007 .

[11]  P. Kannan,et al.  Thermotropic liquid crystalline‐cum‐photocrosslinkable poly(benzylidene arylphosphate ester)s containing the cyclopentanone moiety , 2006 .

[12]  P. Kannan,et al.  Synthesis and characterization of α‐methylstilbene‐ and azobenzene‐based thermotropic liquid crystalline polymers , 2006 .

[13]  R. Velu,et al.  Studies on thermotropic liquid crystalline polyphosphates containing photoreactive dual mesogens , 2005 .

[14]  Menachem Lewin,et al.  Unsolved problems and unanswered questions in flame retardance of polymers , 2005 .

[15]  P. Sakthivel,et al.  Novel thermotropic liquid crystalline-cum-photocrosslinkable polyvanillylidene alkyl/arylphosphate esters , 2004 .

[16]  T. Wang,et al.  Synthesis and characterization of new segmented polyurethanes with side‐chain, liquid‐crystalline chain extenders , 2004 .

[17]  K. M. Lee,et al.  Effect of Flexible Spacer Length on the Rheology of Side-Chain Liquid-Crystalline Polymers , 2003 .

[18]  R. Rathore,et al.  Herring-bone pi-pi interactions in trans-2,6-diphenyl-2,3,5,6-tetrahydrothiapyran-4-one. , 2003, Acta crystallographica. Section C, Crystal structure communications.

[19]  Natalia Boiko,et al.  Photoactive liquid crystalline polymer systems with light-controllable structure and optical properties , 2003 .

[20]  A. Mantecon,et al.  New dimeric LC-epoxyimine monomers with oxyethylene central spacers. Crosslinking study , 2003 .

[21]  V. Cozan,et al.  Side chain thermotropic liquid crystalline polysulfone obtained from polysulfone udel by chemical modification , 2003 .

[22]  V. Cádiz,et al.  Synthesis and crosslinking of polyethers that have mesogenic cores and propargyl groups , 2002 .

[23]  P. Kannan,et al.  Thermotropic main chain liquid crystalline polyesters containing ferrocene and phosphate units: synthesis and characterization , 2002 .

[24]  N. Hurduc,et al.  Synthesis and characterization of some aliphatic–aromatic poly(Schiff base)s , 2001 .

[25]  A. H. Al-dujaili,et al.  Synthesis and liquid crystalline properties of models and polymers containing thiazolo[5,4-d]thiazole and siloxane flexible spacers , 2001 .

[26]  H. Allcock,et al.  Phosphorylation of phosphazenes and its effects on thermal properties and fire retardant behavior , 2000 .

[27]  C. Pillai,et al.  Synthesis of novel liquid crystalline polymers with cross-linked network structures , 2000 .

[28]  K. Lee,et al.  Synthesis and characterization of photocrosslinkable poly(organophosphazene)‐bearing cinnamyloxide side groups , 1999 .

[29]  J. Watanabe,et al.  Fluorescence study on intermolecular complex formation between mesogenic biphenyl moieties of main-chain thermotropic liquid–crystalline polyesters with 7–18 methylene units , 1999 .

[30]  N. Salahuddin,et al.  Photocrosslinked polymers based on pendant extended chalcone as photoreactive moieties , 1999 .

[31]  P. Kannan,et al.  Studies on photocrosslinkable-cum-flame retardant poly(benzylidene phosphoramide ester)s , 1997 .

[32]  J. Mikroyannidis,et al.  Soluble, Rigid-Rod Polyamide, Polyimides, and Polyazomethine with Phenyl Pendent Groups Derived from 4,4''-Diamino-3,5,3'',5''-tetraphenyl-p-terphenyl , 1996 .

[33]  E. Weil.  Advances in sulfur chemistry, vol. 1, Eric Block, editor, JAI press, Greenwich, CT, 1994. $97.50. 212 pgs. , 1995 .

[34]  C. Imrie,et al.  Effect of Spacer Length on the Thermal Properties of Side-Chain Liquid Crystal Polymethacrylates. 2. Synthesis and Characterization of the Poly[.omega.-(4'-cyanobiphenyl-4-yloxy)alkyl methacrylate]s , 1995 .

[35]  M. Shau,et al.  Synthesis, structure, and thermal properties of epoxy‐imide resin cured by phosphorylated diamine , 1995 .

[36]  R. Hikmet,et al.  Anisotropic Networks with Tunable Optical and Mechanical Properties , 1994 .

[37]  Yue Zhao,et al.  Side-Chain Liquid Crystalline Ionomers. 1. Preparation through Alkaline Hydrolysis and Characterization , 1994 .

[38]  H. Allcock,et al.  Synthesis of Photo-Cross-Linkable Chalcone-Bearing Polyphosphazenes , 1994 .

[39]  R. Antony.  Synthesis, characterization, and thermal studies of cardanol‐based polyphosphate esters , 1993 .

[40]  V. Percec,et al.  Liquid crystalline polyethers based on conformational isomerism. Part 28. Noncrystallizable macrocyclics exhibiting enantiotropic liquid-crystalline phases , 1993 .

[41]  Gaṅgādhara,et al.  Novel photocrosslinkable liquid-crystalline polymers: poly[bis(benzylidene)] esters , 1993 .

[42]  H. Kricheldorf,et al.  LC‐polyimides. VII. Thermotropic poly(ester‐imide)s derived from trimellitic acid with phosphonate or phosphate groups in the main chain , 1992 .

[43]  V. Percec,et al.  Liquid-crystal polymers containing macroheterocyclic ligands. 5. Structure of the liquid crystal phases of poly[4-[(11-methacryloylundecan-1-yl)oxy]-4'-(4'-carboxybenzo-15-crown-5)biphenyl] , 1991 .

[44]  J. Stille,et al.  New crosslinking end caps for polyquinoline prepolymers: synthesis, processing, and thermal properties , 1991 .

[45]  Kaushal Kishore,et al.  Pyrolysis gas chromatographic studies on polyphosphate esters of bisphenol A , 1991 .

[46]  T. Chang,et al.  Studies on the thermotropic liquid crystalline polymer. I. Synthesis and properties of polyamide‐azomethine‐ether , 1990 .

[47]  P. Keller.  Photo-crosslinkable liquid-crystalline side-chain polysiloxanes , 1990 .

[48]  A. Aharoni.  Hydrogen-bonded highly regular strictly alternating aliphatic-aromatic liquid-crystalline poly(ester amides) , 1988 .

[49]  B. Moon,et al.  An Effective Method for the Preparation of ω-Bromoalkanols from α,ω-Diols , 1985 .

[50]  P. Morgan,et al.  Aromatic azomethine polymers and fibers , 1987 .

[51]  D. Goldsmith,et al.  Cleavage of cyclic ethers by magnesium bromide-acetic anhydride. SN2 substitution at a secondary site , 1975 .

[52]  W. R. Young,et al.  Stilbene derivatives. New class of room temperature nematic liquids , 1972 .

[53]  G. Heilmeier,et al.  Guest-host Interactions in Nematic Liquid Crystals. A New Electro-optic Effect , 1968 .