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Title
Improving the dispersibility of cellulose microfibrillated structures in polymer matrix by controlling drying conditions and chemical surface modifications
Authors
P. NECHITA and D. M. PANAITESCU
Received
February 22, 2013
Published
Volume 47 Issue 9-10 October-December
Keywords
cellulose microfibrillar structures, surface modification, drying, acetylation, polymer matrix, composites
Abstract
The aim of this paper was to investigate some possibilities to improve the compatibility of cellulose microfibrillated
structures at the fibre-polymer matrix interface level, when they are used as reinforcement in polymer composite
materials. The cellulose microfibrillated structures isolated from bleached softwood pulp by chemical-mechanical
methods were subjected to surface modification by acetylation, aiming to reduce their hydrophilic character. Fourier
transform infrared spectroscopy (FTIR) analyses indicated the acetylation of the hydroxyl groups of cellulose; the
increase of the elastic modulus of the polymer composite materials was due to the good dispersion of the surface
modified cellulose microfibrillar elements in the polymer matrix.
Another method that was tested to reduce the hydrophilic character of cellulose microfibrillated structures in contact
with a polymer matrix was the spray drying, using the atomization of cellulose microfibrils. This method produces
particulate materials with unchanged size and very good potential as reinforcement in composite manufacturing,
utilizing conventional thermoplastic compounding techniques. The improvement in the mechanical properties of the
composites reinforced with spray dried cellulose microfibrillar elements shows that this drying method is the most
suitable for cellulose fibres that are used as reinforcement in hydrophobic polymer matrix, because this procedure
reduces the advanced irreversible hornification phenomenon, which occurs during the oven drying process.
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