Multiphase materials with lignin. IV. Blends of hydroxypropyl cellulose with lignin

Abstract

SynopsisPolymer blends of hydroxypropyl cellulose (HPC) and organosolv lignin (OSL) were prepared by mixing in solutions of both pyridine and dioxane, and casting as films, and by mixing in the melt followed by extrusion. All preparations exhibited partial miscibility as evidenced by a single Tg up to a composition of 40 wt 56 lignin above which phase separation was detected. Dioxane-cast and injection-molded blends were distinguished from the pyridine-cast materials by a positive Tg deviation from additivity, an approximation which adequately described the latter. This positive deviation in Tg is attributed to the formation of a liquid-crystal mesophase with a resultant reduction of amorphous HPC available for interaction with the lignin component. This explanation is supported by a rapid rise in modulus ( -150%) and tensile strength with very low lignin content, and by an associated sharp decline in ultimate elongation. The development of morphological features, as observed by scanning electron microscopy provide further substantiation of this hypothesis.

Lignin Impact on Fibre Degradation: 2—A Model Study Using Cellulosic Hydrogels

“…Beads consisting of blends of lignin and amorphous cellulose were similarly produced from common solutions by regeneration. Polymer morphology and thermodynamics of the lignocellulose blend resemble those of the biocomposite (Rials and Glasser 1989) and depend on lignin structure (Rials and Glasser 1990). In uitro degradation of these lignocellulose beads was compared with degradation of control cellulose beads and of cellulose beads to which powderous lignin was added at time of incubation to show the effects of (1) close physical association with 204 J Sci Food Agric 0022-5142/96/$09.00 8 1996 SCI.…”

Influence of Lignin Type on the Mechanical Properties of Lignin Based Compounds

“…Especially Glasser et al have investigated many blend systems, which they have obtained from solution casting on a small scale. [1][2][3][4][5][6] On similar scale, but using a technical kraft lignin, Sarkanen et al have prepared a lignin compound containing 85 wt.-% lignin and 12.6 wt.-% poly[ethyleneco-(vinyl acetate)]. [7] In an optimized composition this material exhibits a Young's modulus of 1 450 MPa and a stress at break of 26 MPa.…”

Development of Carbon Materials for Energy and Environmental Applications

“…The concentration of unpaired spins was found to be 1.3 9 10 18 spins/g of the carbon material. The spin concentration value of activated carbon from the stems of Limonea acidissima (C WA ) is an order of magnitude lower than that of the spin concentration values reported for commercial acetylene based carbon (3.8 9 10 19 ) and graphon (1.1 9 10 19 ) [30]. The lower spin concentration in our sample is because of the saturation of the dangling bonds with potassium, formed during the carbothermal reduction of K 2 CO 3 , resulting in the formation of surface C-K bonds which subsequently transform (partially) to C-H bonds upon final treatment with conc.…”