Comparative spectroscopic study of the modification of cellulosic materials with different coupling agents

Abstract

ABSTRACT:The reactions of two cellulosic materials (an industrial cellulosic by-product from a Kraft pulp mill facility and a reference material) with three coupling agents, used to improve compatibility between cellulosic reinforcements and thermoplastic matrices, were studied by diffuse reflectance Fourier-transform infrared (DRIFT) spectroscopy and diffuse reflectance ultraviolet-visible spectroscopy. A maleated polypropylene wax (Epolene E-43™) and two silanes (N-2-aminoethyl-3-aminopropyltrimethoxysilane and methyltrimethoxysilane) were used as coupling agents. The two cellulosic materials reacted in a similar way and the three coupling agents were covalently bonded to the cellulose. For the aminosilane, a reaction with cellulose involving a fraction of the amino groups was detected. A simple method, based on the analysis of the oxidation kinetics of treated and untreated materials, was developed to compare the degree of cellulose modification achieved by each coupling agent. The analysis revealed that a reduced fraction of the cellulose reactive groups was converted by esterification with the maleated polypropylene. However, when applied in the appropriate conditions, the two silanes converted most of such cellulose reactive groups. Finally, the reaction of cellulose with mixtures of coupling agents was studied. The aminosilane-treated cellulose reacted with the maleated polypropylene with formation of amide links.

Evaluation of sewage sludge-based compost by FT-IR spectroscopy

“…Absorption bands in the region 1500-1600 cm À 1 could be assigned to the aromatic rings of lignin, 1371 cm À 1 to deformation vibrations of CH 2 in xyloglucans, 1426 cm À 1 to bending vibrations of CH 2 of cellulose, 1738 cm À 1 -stretching vibrations of esters in pectins (Kacurakova et al, 2002). Peaks at 1510Peaks at , 1460Peaks at , 1420Peaks at , 1270Peaks at , 1230Peaks at , 1130 cm À 1 are typical for lignin (Matias et al, 2000;Zancada et al, 2003). The broad band with maximum at 2905 cm À 1 is assigned to CH stretching vibrations in cellulose (Marchessault and Liang, 1960).…”

Preparation and characteristics of polypropylene-graft-maleic anhydride anchored micro-fibriled cellulose: its composites with polypropylene

“…Because the properties of such composites depend on the degree of interfacial adhesion as well as the properties of the individual components, the modification of pristine cellulose might play a key role in the cellulosic polymer composites. [13][14][15] Numerous research groups have been performed to enhance the interfacial adhesion for efficient transfer of stress from the matrix to the fibers, using physical treatments [16][17][18] as well as chemical treatments [1,[19][20][21][22][23] (pretreatment of fiber surfaces by coupling agents, such as silanes and isocyanates, and/or modification of the matrix by grafting with reactive moieties, such as acrylic acid, acrylic esters, maleic anhydride, etc.). Of all these attempts, maleic anhydride grafted polyolefins were found to be one of the most efficient for a composite of cellulose fibers and polyolefin matrices.…”

Modification of cellulose fibres with organosilanes: Under what conditions does coupling occur?

“…The only exception to this state of affairs, before our work, was a thorough study by Herrera-Franco and co-workers [8], which clearly showed that prehydrolyzed siloxanes only reacted with the surface of cellulose fibers (≡Si-OH + ≡C-OH) at high temperature. More recently, Matias et al have confirmed the occurrence of this reaction using diffuse reflectance FTIR and UV-vis spectroscopy [9].…”