Critical investigation of the substituent distribution in the polymer chains of hydroxypropyl methylcelluloses by (LC-)ESI-MS.

Three hydroxypropyl methylcellulose samples (HPMC1-3, DS(Me) = 1.45, 1.29, and 1.

Structure and properties of aqueous methylcellulose gels by small-angle neutron scattering.

Cold, semidilute, aqueous solutions of methylcellulose (MC) are known to undergo thermoreversible gelation when warmed. This study focuses on two MC materials with much different gelation performance (gel temperature and hot gel modulus) even though they have similar metrics of their coarse-grained chemical structure (degree-of-methylether substitution and molecular weight distribution). Small-angle neutron scattering (SANS) experiments were conducted to probe the structure of the aqueous MC materials at pre- and postgel temperatures.

Simultaneous determination of substituent patterns in partially acid hydrolyzed O-Me/O-Me-d(3)-cellulose and quantification of the obtained oligomers by HPLC-ESI-MS.

Substituent patterns in oligosaccharide derivatives obtained from methyl cellulose were determined up to DP10 by electrospray ionization mass spectrometry employing separation of the oligomer fractions by HPLC. Oligosaccharides were labeled with meta-aminobenzoic acid after perdeuteromethylation and partial hydrolysis of methyl cellulose, enabling simultaneous quantification according to DP by HPLC/UV. Control of the HPLC-method was performed with a defined oligomer mixture obtained from β-cyclodextrin.

Comprehensive analysis of the substituent distribution in hydroxyethyl celluloses by quantitative MALDI-ToF-MS.

Three HECs with a high MS (HEC 1: 1.89, HEC 2: 1.94, HEC 3: 3.

New approaches to the analysis of enzymatically hydrolyzed methyl cellulose. Part 2. Comparison of various enzyme preparations.

In this part of our studies, dealing with new approaches to the analysis of enzymatically hydrolyzed methyl cellulose, five different enzymes or enzyme preparations containing endoglucanases (from Bacillus agaradhaerens Cel 5A, Trichoderma reesei, Trichoderma viride, and two obtained from Trichoderma longibrachiatum) were used to hydrolyze six different methyl celluloses (MCs). The main goal was to investigate whether enzymes could be used for determination of the heterogeneity of the substituent distribution along the cellulose chain. To obtain information about the heterogeneity, it was necessary to gather information on how the enzymes affect hydrolysis.

New approaches to the analysis of enzymatically hydrolyzed methyl cellulose. Part 1. Investigation of the influence of structural parameters on the extent of degradation.

Six methyl celluloses (MCs), one with a degree of substitution (DS) of 1.32 and five with DS between 1.83 and 1.

Comprehensive analysis of the substituent distribution in the glucosyl units and along the polymer chain of hydroxyethylmethyl celluloses and statistical evaluation.

Hydroxyethylmethyl celluloses (HEMC, DS(Me) 1.46-1.66, DS(HE) = 0.