Green Preparation Of Soluble Polyurethane And Fluorene-Based Conjugated Polymer

Polyhydroxyurethane is a kind of modified polyurethane.The nonisocyanate polyhydroxyurethanes are synthesized by using natural oil as polymeric monomer,which has the advantage of low cost and easy availability.But the polyhydroxyurethanes has some disadvantages,such as the low molecular weight,as well as poor solubility in the organic solvent.Therefore,this paper chooses other monomers to prepare modified polyurethanes via a non-toxic and green synthetic method which produces the final products with better solubility and higher molecular weight than that of polyhydroxyurethane.The π-conjugated polymers have semiconductive and luminous properties.Especially,the luminosity of poly[(9,9-dioctylfluorene-2,7-diyl)-(1,2,4,5-tetrafluoro-1,4-phenylene)](PDOF-TP)is remarkable,which made it an ideal material for light-emitting devices.However,the previous synthesis methods are complicated and expensive.So this paper investigates a novel synthesis method with easier and cheaper preparation condition than that of previous synthesis.We hope this method can be widely used in the preparation of π-conjugated polymers.In this paper,two parts are mainly studied as follows:1.The soluble poly(acetal-etherurathane)s are synthesized from six-membered di-cyclic carbonate,di-trimethylolpropane di-cyclic carbonate and Jeffamine derivatives using a catalyst-free and green method.We use two kinds of different diamine monomers to synthesize the poly(acetal-etherurathane)s.Polyhydroxyurethane is obtained firstly,and then directly acetylated without separation and purification.All the operations are in one-pot.The molecular weight of poly(acetal-etherurathane)s are more than 20000.They are soluble in most organic solvents.However,poly(acetal-etherurathane)which lacked methyl group at the β position of the ether bond in hard segment is soluble not only in most organic solvent but also in water.This result will have potential application in the product development of biomimetic materials.2.This article also investigates the preparation conditions of PDOF-TP.We use1,2,4,5-tetrafluorobenzene and 2,7-dibromo-9,9-dioctylfluorene as monomers andcommercially available reagent-grade solvents through direct arylation polycondensation in aerobic conditions to synthesize PDOF-TP.(The PDOF-TP was obtained in original reaction under conventional oxygen-and moisture-free conditions).The yield of PDOF-TP obtained by using reagent-grade solvent(DMAc)and reacting at125 ℃for 24 hours in sealed air atmosphere is 67%,and the molecular weight of the PDOF-TP reaches 10000.This is a reduction in cost and operational difficulty compared to the original reaction conditions.The yield of PDOF-TP obtained by using reagent-grade solvent(DMAc)and reacting at 100 ℃ for 12 hours in nitrogen atmosphere is 63%,and the molecular weight reaches 12800.It can be substituted for synthesis under anhydrous anaerobic conditions.The operation is simple and the cost is greatly reduced.The method is green and non-toxic,which will provide an important reference for the synthesis of other π-conjugated polymers,as well as broad potential application.