Determination of Unsaturation Distribution in Polybutadienes by Infrared Spectrometry

Abstract

b The availability of polybutadienes with widely varying structures has led to a study of the absorption of cis-1,4 addition in the 12to 16-micron region and the development of a method for unsaturation distribution using high cis-l,4, trans-l,4, and 1,2(vinyl) polymers as the only calibration standards. The cis-1,4 absorption band, at 13.5 microns in high cis polymers, varies in position and shape as the amount of cis-1,4 addition changes. An empirical function of the area of the absorption band between 12.0 and 15.75 microns was used to measure cis-1,4 addition. frans-l,4 and 1,2(vinyl) addition was measured at 10.3 and 1 1 .O microns, respectively. The method was applied successfully to a number of polybutadienes with widely varying distributions. The results indicate that this method, derived solely from polybutadienes, can be applied with confidence to polybutadienes with any unsaturation distribution. N THE polymerization of butadiene,

Aplicações da espectroscopia de infravermelho com transformada de Fourier para especiação isomérica de Polibutadienos hidroxilados utilizados na síntese de polímeros Pu-Propelentes

“…A determinação da microestrutura de PBLH por análise no infravermelho, em solução, baseia-se nos estudos realizados com polibutadieno não funcional (PB) [14][15][16][17][18] . Estes estudos utilizam a região do espectro infravermelho abaixo de 1000cm -1 , onde ocorrem as vibrações de deformação fora do plano para ligações olefínicas.…”

“…Estes estudos utilizam a região do espectro infravermelho abaixo de 1000cm -1 , onde ocorrem as vibrações de deformação fora do plano para ligações olefínicas. Na literatura [3][4][13][14][15][16][17][18] A resolução deste sistema de equações fornece os teores dos isômeros configuracionais do PBLH.…”

Surface hydroxylation of styrene–butadiene–styrene block copolymers for biomaterials

“…Since each polybutadiene used for calibration contained some of the other types of double bonds the procedure of Silas, et al (1959) and their assumption of 100% unsaturation was used to get the true absorptivities for each of the three double bond types. A similar procedure was used in determining the hydroxyl absorptivities from the polyvinyl alchohol-polyvinyl acetate copolymer films (the copolymer was used to avoid interferences from the crystalline environment present in a film of polyvinyl alchohol homopolymer).…”

“…The method of Silas et al (1959) was used to compute the absorptivities of the individual polybutadiene isomers. The absorptions at each of the three major analytical frequencies (967, 910 and 737 cm l )…”

“…at 967 cm -1 for the high trans content polymer). Using the effective molar absorptivities calculated according to equation AI-l, with the assumption of 100% unsaturation in the calibration polymers, the weight fractions of each isomer in each polymer and the true absorptivities of each functional group were calculated using the equations described by Silas (1959).…”