Találati lista | Tudóstér

001-es BibID:	BIBFORM064106
Első szerző:	Nagy Tibor (vegyész)
Cím:	Uncatalyzed reactions of 4,4·-diphenylmethane-diisocyanate with polymer polyols as revealed by matrix-assisted laser desorption/ionization mass spectrometry / Tibor Nagy, Borbala Antal, Anita Dekány-Adamoczky, Jozsef Karger-Kocsis, Miklos Zsuga, Sandor Kéki
Dátum:	2016
ISSN:	2046-2069
Megjegyzések:	The uncatalyzed reactions of polyols including polypropylene glycol (PPG, Mn = 2000 g/mol), polytetrahydrofuran (PTHF, Mn = 1000 g/mol), poly(?-caprolactone)-diol (PCLD, Mn = 2000 g/mol) and polypropylene glycol glycerol triether (PPG_GL, Mn = 1000 g/mol) with 4,4`-diphenylmethane-diisocyanate (MDI) were studied using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The reactions between these polyols and MDI were monitored in time and first-order consecutive reaction kinetics for the formations of polyols end-capped with MDI units were established. The fractional MALDI-TOF MS intensities obtained for the different polymer series at various reaction times were converted into molar fractions versus time data by means of the estimated relative MALDI-TOF MS response factors from which the corresponding rate constants and the relative reactivities of the hydroxyl groups of polyols were determined. It was found that the pseudo first-order rate constants for the polyol-MDI reaction decreased in the order of PCLD > PTHF > PPG ? PPG_GL. It was also ascertained that the reactivity of the unreacted hydroxyl groups of the diols does not change significantly after the first one has been reacted. On the contrary, in the case of PPG_GL it was found that the reactions of the hydroxyl groups with MDI proceed faster after either of the three hydroxyl groups has been reacted, suggesting positive substitution effect for this system.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban polyurethane kinetics MALDI-TOF MS polyols 4,4`-Diphenylmethane-Diisocyanate
Megjelenés:	RSC Advances. - 6 : 52 (2016), p. 47023-47032. -
További szerzők:	Antal Borbála (1988-) (vegyész) Dékány-Adamoczky Anita (1985-) (anyagmérnök) Karger-Kocsis József (1950-) (vegyészmérnök) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:	K-101850 OTKA NTP-EFÖ-P-15 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: