Benzylated pulps from sugar cane bagasse |
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Authors: | R PEREIRA S P CAMPANA FILHO A A S CURVELO A GANDINI |
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Institution: | (1) Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Caixa Postal 780, CEP: 13560- 970 Sao Carlos SP, Brasil;(2) Ecole Francaise de Papeterie de des Industries Graphiques (INPG), BP 65, 38402 Saint Martin d'Heres, France |
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Abstract: | An optimized ethanol/water process has been employed for the pulping of fibres from sugar cane bagasse. After pretreatment
with aqueous NaOH, unbleached pulps were subjected to benzylation at 110 °C for different periods of time. The resulting purified
products were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography
(GPC) and infrared spectroscopy (IR). The results showed that benzylation proceeded to various extents depending on the reaction
time, as assessed by weight gain. During the first 3 h, a loss of mass was observed due to the occurrence of benzylation of
low molecular weight polyoses, which were eliminated in the purification step. After that period of time a drastic weight
increase was observed probably because crystalline regions had developed. The samples with low degrees of benzylation were
insoluble, whereas the more benzylated counterparts showed limited solubility in THF. Partially soluble samples and a completely
soluble one showed very different GPC elution profiles. This may be attributed to the efficiency of the pre treatment which,
in the latter case, employed more concentrated alkali. Thermogravimetric analyses showed that all samples were degraded above
310 °C. Glass transition temperatures ranged between 42 °C and 65 °C, increasing as the extent of benzylation increased
This revised version was published online in August 2006 with corrections to the Cover Date. |
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Keywords: | bagasse pulp benzylation Tg cellulosicthermoplastics |
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