تهيه پلي استرها و پلي آميد هاي تمام آروماتيك مقاوم حرارتي و فعال نوري جديد بر پايه آمينو اسيد S-والين با استفاده از روش هاي منداول و شيمي سبز

چكيده انگليسي :

AbstractSynthesis and application of chiral macromolecules are active research areas Lately wehave synthesized optically active polymers by different methods In this project a series ofnovel thermally stable polyesters PE s and polyamides PA s based on chiral amino acidmoiety such as S valine were synthesized and some physical properties of them wereinvestigated For this purpose at first 5 3 methyl 2 1 8 naphthalimidyl butanoylamino isophthalic acid 42 was prepared in three steps This monomer have chiral amino acidmoiety and readily can be converted to bioactive polymers Extensive studies onbiodegradable polymers have been performed because the increase in plastic wastes causesserious environmental problems Aromatic polyesters are thermally stable polymers andexhibit excellent mechanical and electrical properties However most PEs encounterprocessing difficulties due to their high glass transition or melting temperatures coupledwith insolubility in most organic solvents In other to improve their solubility severalapproaches have been proposed based on the incorporation of flexible segments in thepolymer backbone without sacrificing the heat resistance PEs are biodegradable polymersthat have always been an attraction from the early days of Carothers so a series of novelPEs were prepared by the reaction of diacid monomer 42 with several aromatic diols viadirect polyesterification with TsCl Py DMF system as condensing agent Inherentviscosities of these polymers were in the range of 0 27 0 61 dL g and it showed goodthermal stability The PEs were characterized using FT IR 1H NMR UV visspectroscopy fluorimetry and elemental analysis Despite the exceptional properties ofPAs as inertness toward chemicals and high temperatures their use are encountered withsome drawbacks caused by low organosolubility and high softening temperatures Introduction of bulky pendent groups is a common way for improvements of PAsprocessability without breaking down of thermal resistances and the use of chiral pendentgroups can lead not only to the formation of optically activity PAs but also to thepolymers with processability enhancements These upgraded polymers can be applied aschiral stationary phases in HPLC techniques for resolution of racemic mixtures ionicliquids IL s have attracted a great deal of interest as environmentally benign solvents forpolymer synthesis Traditional solvents are volatile most of them flammable toxic andharmful Thus removing organic solvents in polymer synthesis is very important in thedrive towards environmentally friendly technologies In a search for more efficient and atthe same time more environmentally green processes chemists have recently turned theirinterest to the new class of potential solvents namely to ILs and have become a part of theso called green chemistry However the high cost of most room temperature ionic liquidsand apprehension about their toxicity has led researchers to discover the use of morebenign salts in the molten state as useful alternatives Recently moltentetrabutylammonium bromide TBAB was used as a low toxic and cost effective IL in anumber of useful synthetic transformations So for the first time use of TBAB TPP systemfor polyamidation reaction eliminate the need of volatile and toxic solvents PAs weresynthesized via two different methods conventional heating in IL and traditional solvent NMP TPP CaCl2 Py was used as a condensing agent for direct polycondensation ofmonomer 42 by reflux conditions whereas in IL as a media used only triphenyl phosphite Inherent viscosities of these polymers were in the range of 0 41 0 78 and 0 32 0 69 dL grespectively and it showed good thermal stability These compounds were characterized byFT IR 1H NMR UV Vis specific rotation elemental analysis These polymers haveflexible amino acid and bulky pendent group and consequently reduce packing efficiencyof polymer chain therefore have very high solubility Also thin transparent films of thesepolymers can be prepared Key

هاشمي، الهه

تهيه پلي استرها و پلي آميد هاي تمام آروماتيك مقاوم حرارتي و فعال نوري جديد بر پايه آمينو اسيد S-والين با استفاده از روش هاي منداول و شيمي سبز

روش ويلز ماير , پليمرشدن , آميدي كردن