Abstract
Two series of new hexasubstituted cyclotriphosphazene derivatives were successfully synthesized and characterized. These derivatives are differentiated by two types of linking units in the molecules such as amide-azo (6a–j) and azo-azo (8a–j). The homologues of the same series contain different terminal substituents such as heptyl, nonyl, decyl, dodecyl, tetradecyl, hydroxyl, carboxyl, chloro, nitro, and amino groups. All the intermediates and final compounds were characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), and Carbon, Hydrogen, and Nitrogen (CHN) elemental analysis. Liquid crystal properties for all compounds were determined using polarized optical microscope (POM). It was found that only intermediates 2a–e with nitro and alkoxyl terminal chains showed a smectic A phase. All the final compounds with alkoxyl substituents are mesogenic with either smectic A or C phases. However, other intermediates and compounds were found to be non-mesogenic. The study on the fire retardancy of final compounds was determined using limiting oxygen index (LOI) method. The LOI value of pure polyester resin (22.53%) was increased up to 24.71% after treating with 1 wt% of hexachlorocyclotriphosphazene (HCCP). Moreover, all the compounds gave positive results on the LOI values and compound 6i with the nitro terminal substituent showed the highest LOI value of 27.54%.
Highlights
The extensive exploration of phosphazene liquid crystalline materials having flexible ordered structures has led to the discovery of new properties and applications, such as advanced technological devices or smart biological and pharmacological uses [1]
The 1H-nuclear magnetic resonance spectroscopy (NMR) spectrum for intermediate 1 showed a small broad singlet at δ 10.70 ppm which was assigned to the hydroxyl proton while four doublets in the aromatic region (δ 6.90–8.40 ppm) were assigned to four different aromatic protons
The limiting oxygen index (LOI) value of polyester resin was increased to 24.71% when incorporated with 1 wt% of HCCP
Summary
The extensive exploration of phosphazene liquid crystalline materials having flexible ordered structures has led to the discovery of new properties and applications, such as advanced technological devices or smart biological and pharmacological uses [1]. The molecules are arranged in a highly ordered system having the positional and orientational order. The solid absorbs some heat and melts into a liquid crystal phase whereby the molecules are able to move freely, disrupting the positional order without changing the orientational order [8,9]. INthevtwerothlienleksins,gtounoiutsr best knowledge, only few kinds of cyclotriphosphazene liquid crystals compounds with two linking units have been studied. Substituted cyclotriphosphazene derivatives were extensively studied as fire retarEdvaenntst,htohue ginhvtehsetisguatbisotnituotfetdhecyccylcoltorpiphhoospsphahzaezneen-ebadseerdivcaotmivpesouwnedrse hexavteinngsivoerglyansticudsiidede aarsmfisre raentadrdpaonstsse, sthsienignvthesetilgiqatuioidn ocrfytshtealcyacnldopfhiroesprheatazrednaen-bt abseehdacvoimouprouisndstsilhl anvoint gboeirngganfiuclslyideexaprmlorseadn.d pOorsdseinssairnilgy,ththeeliqchuliodricnreysattaolmansdinfirtehereHtaCrdCaPntabreehraevpiloacuerdiswstiitlhl noorgt abneiicngsifduellayremxpinloroerdd.erOtrodifnoarrmily, thhaelocghelonr-ifnreeeatfoirme-sreintarthdeanHt CcComP paoreunredpsl.acTehdewtirtahdoitriognanalic hsaidloegaernm-coinntoairndienrgtofifroermrehtaarldoagnetns-frisee fiforer-briedtdarednandtuceomtopoiutsndtos.xiTchitey traandditiosanfaeltyhalaowgaerne-nceosnsta[i3n0in].g Ifinrteerreesttairndgalyn,tstihsefoirnbciodrdpeonradtuioentooifts thoexxicaictyhlaonrodcsyacfleottyripawhoasrpenheaszsen[3e0i]n.tIonatecroemstipnogulyn,dthisetioncinocrrpeoarsaetitohne roefshisetxaanccheloofrothceycmloattreirpihalotsopwhaazrdens e iingtnoitaiocno.mTphouusn, dthisistoreinsecarrecahseftohceusreedsisotanncteheofpthreepmaraatteiornialotfowaarndeswigsneirtiieosn.oTf hhuesx,atshuibssrteitsuetaerdch fcoycculsoetrdipohnotshpehpazreepneardaetiroivnaotifvaesnwewithsearmieisdeofahnedxaazsoub(Ssetirtiueste1d) cayncdlotwtriopahzoosp(Shearzieesn2e)dberridivgaitnigveusnwitsit.h aEmxtiednesaionnd oafzoth(eSelirnieksin1g) aunndit tgwreoaatlzyoe(nSherainecse2s)bbortihdgthinegLuCniptsh.aEsexsteannsdiotnheofththeermlianlksintagbiulintyit ogfretahtely ecnohmapnoceusnbdost.h the LC phases and the thermal stability of the compounds. O OCH3 A1 OCOH3 KAO1H, EOtOCHH3 KrOreefHAlful,1uxExO,t,5O5hhH KrOefHlOuO, xEH,t5OhH
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