scholarly journals Compositional Analysis of the High Molecular Weight Ethylene Oxide-Propylene-Oxide Copolymer by MALDI Mass Spectrometry

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Orwa Jaber Housheya ◽  
Charles Wilkins
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Ethylene Oxide ◽  
High Molecular Weight ◽  
Propylene Oxide ◽  
Compositional Analysis ◽  
Maldi Mass Spectrometry

Influence of Polyether Copolymer Configuration on Polyurethane Reaction: A Mass Spectrometry Analysis

2003 ◽  
Vol 22 (1) ◽  
pp. 23-42 ◽  
Author(s):  
Wu Suen ◽  
Jennifer Percy ◽  
Shaw L. Hsu ◽  
Igor A. Kaltashov ◽  
Howard D. Stidham
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Ethylene Oxide ◽  
Molecular Weight Distribution ◽  
Propylene Oxide ◽  
Weight Distribution ◽  
Quantitative Description ◽  
Mass Spectrometry Analysis ◽  
Oxide Content ◽  
Natural Isotopic Abundance

Matrix Assisted Laser Desorption Ionization Time-of-Flight mass spectrometry has been applied to obtain the molecular weight distribution of two polyether copolymers containing ethylene oxide and propylene oxide units. The measured molecular weights and their distributions were surprisingly different from the expected. Based upon the natural isotopic abundance, it was possible to provide a quantitative description of the number of ethylene oxide and propylene oxide units as a function of molecular weight. Important information on composition drift and heterogeneity can be obtained from the 3-D bivariate deconvolution of the mass spectra. As the molecular weight of a random copolymer increased, the ethylene oxide content also increased. A copolymer system with a narrow molecular weight distribution did not necessarily have a narrow composition distribution. These results provide information at the molecular level regarding the hydrophilicity of these copolymers used in polyurethane formulations.

Phase Separation in Al2O3 Sol-gel System Incorporated with High Molecular Weight Poly(ethylene oxide)

2007 ◽  
Vol 1007 ◽  
Author(s):  
Yasuaki Tokudome ◽  
Kazuki Nakanishi ◽  
Koji Fujita ◽  
Kiyotaka Miura ◽  
Kazuyuki Hirao
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Ethylene Oxide ◽  
High Molecular Weight ◽  
Propylene Oxide ◽  
Bet Surface Area ◽  
Pure Alumina ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
High Molecular Weight Poly

ABSTRACTPure alumina monoliths with well-defined macropores and mesostructured skeleton have been synthesized via a spontaneous route from the aqueous and ethanolic solution of aluminum salts in the presence of propylene oxide and high molecular weight poly(ethylene oxide)(PEO). The addition of propylene oxide to the starting solution controls the gelation, while the addition of PEO induces the phase separation. Appropriate choice of the starting composition, with which the phase separation and gelation concur, produces large-dimension (10mm×10mm×10mm), bicontinuous macroporous Al2O3 monoliths. The mean size of the continuously connected pores is controlled in the micrometer range, depending on the PEO concentration and polarity of the solution. On the other hand, micropores and mesopores, originated from the interstices among primary particles, exhibit median pore size of about 2.6 nm and the BET surface area as high as 396 m2/g after dried temperature at 40 °C.

scholarly journals High molecular weight SOA formation during limonene ozonolysis: insights from ultrahigh-resolution FT-ICR mass spectrometry characterization

2012 ◽  
Vol 12 (1) ◽  
pp. 2167-2197
Author(s):  
S. Kundu ◽  
R. Fisseha ◽  
A. L. Putman ◽  
T. A. Rahn ◽  
L. R. Mazzoleni
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Homologous Series ◽  
Condensation Reaction ◽  
Reaction Pathways ◽  
Ultrahigh Resolution ◽  
Group Iii ◽  
Group Ii ◽  
Ft Icr

Abstract. The detailed molecular composition of secondary organic aerosols (SOA) from limonene ozonolysis was studied using ultrahigh-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. High molecular weight (MW) compounds (m/z > 300) were found to constitute a significant number fraction of the identified SOA components. Double bond equivalents (DBE = the number of rings plus the number of double bonds) increased with MW. The O:C ratios and relative abundances of compounds decreased with increasing MW. The mass spectra of limonene contain 4 distinct clusters of negative ions: Group I (140 < m/z < 300), Group II (300 < m/z < 500), Group III (500 < m/z < 700) and Group IV (700 < m/z < 850). A number of CH2 and O homologous series of low MW SOA (Group 1) with carbon number 7–15 and oxygen number 3–9 were observed. Their occurrence can be explained with isomerization and elimination reactions of Criegee radicals, reactions between alkyl peroxy radicals, and scission of alkoxy radicals resulting from the Criegee radicals. Additionally, fragmentation analysis and observations of formaldehyde homologous series provide evidence for aerosol growth by the reactive uptake of generated gas-phase carbonyls in limonene ozonolysis. The decreasing O:C ratios between group of compounds indicated the importance of condensation (aldol and esterification) reaction pathways for high MW compound formation. However, the prominent DBE changes of 2 between the groups of compounds and selected fragmentation (MS/MS) analysis of Group II and Group III ions indicated a predominance of non-condensation (hydroperoxide, Criegee and hemi-acetal) reaction pathways. A reaction matrix created with the combination of low MW SOA, hydroperoxides, and Criegee radicals indicated higher frequencies for the hemi-acetal and condensation reaction pathways. Overall, the combined approach confirms the importance of non-condensation reaction pathways over condensation reaction pathways. Among the non-condensation reaction pathways, hemi-acetal reactions appear to be most dominant followed by hydroperoxide and Criegee reactions.

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