Hydroxypropyl methylcellulose substituent analysis and rheological properties

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• 作者：Hannah Akinosho ; Samantha Hawkins ; Louise Wicker
• 关键词：Hydroxypropyl methylcellulose ; FT-IR ; Raman ; Rheology ; Crystallinity ; Methylation
• 刊名：Carbohydrate Polymers
• 出版年：2013
• 出版时间：15 October, 2013
• 年：2013
• 卷：98
• 期：1
• 页码：276-281
• 全文大小：1324 K

文摘

The methyl and hydroxypropyl substituents in hydroxypropyl methylcellulose (HPMC) affect the resulting gel properties. These substituents in five HPMC gels were characterized using Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, small-amplitude oscillatory shear measurements, and differential scanning calorimetry (DSC). In FT-IR spectra, the most intense peak appeared at 1053 cm^?1, denoting the presence of the glucose ring. The ratio of peak intensities at 1452 cm^?1, which represents CH absorptions, and at 1053 cm^?1 (I₁₄₅₂/I₁₀₅₃) and percent methylation from gas chromatography exhibited a linear association (r² = 0.6296). The broadening of the Raman spectra indicated that the relative crystallinity of HPMC decreases with increasing hydroxypropyl contents. DSC showed no linear relationship between the percent hydroxypropylation in HPMC and the percentage of free water in an HPMC gel. Small-amplitude oscillatory shear measurements revealed that the formation of an entanglements networks and/or weak gel depends on substituent contents.