ATR−FTIR Studies of Poly(propylene oxide)/Polybutadiene Bi-Soft Segment Urethane/Urea Membranes

Abstract

ATR−FTIR is used to investigate the hydrogen-bonding properties of urethane/urea polymers with two soft segments, poly(propylene oxide) and polybutadiene. The polymers are prepared by extending a poly(propylene oxide)-based triisocyanate-terminated prepolymer (PU) with poly(butadienediol) (PBDO). The CO and N−H stretching bands in the spectra of the polymers are deconvoluted into five components, which are ascribed to different free and hydrogen-bonded groups. Results gave evidence of hydrogen bonding between hard/hard segments, leading to the formation of aggregates of urethane/urea groups. This aggregation changed upon variation of the proportion of the two soft segments in the membranes. The increase of PBDO content in the membranes leads to an improvement of the mixing of the two soft segments and also the decrease of the urethane/urea aggregation.

Tomato GDSL1 Is Required for Cutin Deposition in the Fruit Cuticle

“…The carbonyl stretching vibration centered at 1729 cm 21 displayed a shoulder at 1712 cm -1 . Similar lower frequency carbonyl bands have been observed in the gel state of phospholipids with iso-and anteiso-branched fatty acids (Mantsch et al, 1987) and in polyurethane polymers (Queiroz et al, 2003). Such splitting of the carbonyl band in two components is a common feature, attributed to hydrogen bonding (Blume et al, 1998;Queiroz et al, 2003).…”

“…Similar lower frequency carbonyl bands have been observed in the gel state of phospholipids with iso-and anteiso-branched fatty acids (Mantsch et al, 1987) and in polyurethane polymers (Queiroz et al, 2003). Such splitting of the carbonyl band in two components is a common feature, attributed to hydrogen bonding (Blume et al, 1998;Queiroz et al, 2003). The relative increase in the intensity of the 1712 cm 21 shoulder suggests that the ester carbonyl groups are more involved in hydrogen bonding following the decrease in GDSL1 expression.…”

Tailoring of phase‐segregation structures in two‐soft‐segment urethane/urea polymer membranes

“…The increase in the polybutadiene concentration yields a decrease in the aggregate formation and therefore favors the enhancement of molecular mixing. 15 In this work, two-soft-segment membranes cast from solutions yielding urethane/urea polymers with two soft segments of poly(propylene oxide) and polybutadiene are investigated with two main objectives:…”

"Caracterização estrutural e óptica de elastômeros dopados com ferrofluidos"

“…For all the swelling time in toluene and ferrofluid the 50/50 and 60/40 samples were those that present the greatest induced birefringence under stretching. O grau de segregação ou mistura entre os segmentos rígidos e flexíveis presentes no elastômero podem ser estimados através do número de ligações do hidrogênio com o nitrogênio presentes entre os grupos de uretano/uréia e entre os grupos deóxido de poli(propileno) e uretano/uréia [7,9]. Estiramentos podem promover diferentes estadosópticos e micromodulações da superfície dos elastômeros [10,11].…”

“…A caracterização dos filmes por espectroscopia no infravermelho (IV) e análise térmica dinâmico-mecânica (DMTA) mostrou que o aumento da concentração de poli(butenodiol) (PBDO) enfraquece as pontes de hidrogênio entre os grupos uretano-uréia aumentando a mobilidade das cadeias e favorecendo a mistura com oóxido de 1 2 poli(propileno). Depois disso, a espectroscopia de reflexão total atenuada (ATR) e no infravermelho com transformada de Fourier (FTIR) [7] e a microscopia eletrônica de transmissão (TEM) [8] também foram usadas para confirmar o comportamento das separações de fases dos grupos flexíveis no elastômero.…”