Dipole Moments of Poly(ethylene oxide) and Poly(vinylcrown ether)

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1 Dipole moment of poly(ethylene oxide)The dipole moments of poly(ethylene oxide) with different molecular weights were determined from dielectric constant and density measurements performed on their dilute benzene solutions over the temperature range from 25 to 55ﾟC.The Values of average dipole moment per repeat unit, mu, at 25ﾟC were 1.037D (M_W=4.6X10^4), 1.039D(M_W=9.5X10^4), 1.038D(M_W=27X10^4), 1.041D(M_W=57X10^4) and 1.042D (M_W=86X10^4)(D ; debye unit, Mw ; weight average molecular weight). mu for the PEO chains was constant to within 0.5% for the cited range of molecular weight. The dipole moment ratio was calculated as <mu^2>/nm^2=0.47_2*0.00_2(at 25ﾟC), where n and m are number of bond dipoles and their dipole moment. Temperature coefficient averaged for five polymer samples was dln<mu^2>/dT=(1.9_4*0.2_7)X10^<-3>K^<-1>.2 Synthesis and dielectric property of polyvinylbenzo-15-crown-5The preparation of the macromer, 4'-vinylbenzo-15-croun-5(I), is as follows. Catechol was converted to catechol diacetate, followed by a Fries rearrangement which produced 3,4-dihydroxyacetophenone(VI). VI was reacted with 1,11-dichloro-3,6,9-trioxaundecane to form 4'-acetobenzo-15-crown-5(VIII). VIII was reduced with NaBH4 and the resulting alcohol was dehydrated with a trace of p-toluene sulfonic acid to form I. Polyvinylbenzo-15-crown-5 was prepared by radical polymerization using azobis(isobutylonitrile) as initiator at 70 ﾟC. The dipole moment measured in benzene by use of the three terminal platinum cell (cell capacitance : 26.485pF) was 2.2773D(25ﾟC). Temperature coefficient was dln<mu^2>/dT=1.54X10^<-3>K^<-1>.