Increased Water Resistance of CTMP Fibers by Oat (Avena sativa L.) Husk Lignin

Abstract

The insertion of oat husk lignin onto chemithermomechanical pulp (CTMP) fibers was studied to increase fiber hydrophobicity. The pretreated pulp samples were subsequently used for preparation of handsheets for characterization. Treatment of CTMP with laccase in the presence of oat husk lignin resulted in a significant increase in hydrophobicity of the handsheet surface, as indicated by dynamic contact angle analysis. Water absorption time of 8 s was obtained with initial contact angle of 118°. Although the handsheet's brightness was reduced by 33%, tensile index was only subtly decreased. Neither laccase nor oat husk lignin alone gave much improved water absorption times. Therefore, handsheets made of laccase-treated pulp with and without oat husk lignin were further examined by XPS, which suggested that both laccase and oat husk lignin were inserted onto CTMP fibers. The oat husk lignin was distributed as heterogeneous aggregates on the handsheet surface whereas laccase was uniformly distributed. Evidence was obtained that the adsorbed laccase layer formed a noncovalent base for the insertion of oat husk lignin onto fiber surfaces.

Determination of surface-accessible acidic hydroxyls and surface area of lignin by cationic dye adsorption

“…In the current study, the estimated proportion of lignin accessible for Azure B in wheat straw suggests that lignin is largely located on the porous surfaces and in the conductive tissues such as the xylem where lignin has been mentioned to be unwettable (Laschimke, 1989). This is consistent with the fact that lignin is the principal component of water conducting tissues of vascular plants, and that isolated oat husk lignin increases water resistance of lignocellulosic fibers (Sipponen et al, 2010). …”

Calcium Chelation of Lignin from Pulping Spent Liquor for Water-Resistant Slow-Release Urea Fertilizer Systems

“…Lignin is known to provide water resistance to lignocellulosic materials such as cellulosic fibers. 32 The properties of the two lignins obtained from the pulping spent liquor were studied to better understand how they affect water penetration and dissolution of urea from the impregnated straws.…”

Starch-Based Biofoams Reinforced with Lignocellulose Nanofibrils from Residual Palm Empty Fruit Bunches: Water Sorption and Mechanical Strength

“…In the latter case, starch is of great interest given its low cost, availability, and compostability. − Unfortunately, critical limitations arise from starch’s high hydrophilicity and poor mechanical integrity. , In fact, starch-based porous materials lack mechanical strength in wet condition and display limited thermal resistance. Such drawbacks can be addressed by incorporation of cellulosic fibrils, especially if they contain residual lignin, which may endow the system with improved water resistance. , Moreover, it is expected that lignin-containing nanocellulose combined with starch is compostable and completely biodegradable, adding to its potential for packaging. Thus, this work addresses the synthesis of a new class of biofoams consisting of starch (amylopectin) reinforced with LCNF from EFB, which were tested for their mechanical strength and water resistance.…”

“…Such drawbacks can be addressed by incorporation of cellulosic fibrils, especially if they contain residual lignin, which may endow the system with improved water resistance. 31,32 Moreover, it is expected that lignincontaining nanocellulose combined with starch is compostable and completely biodegradable, adding to its potential for packaging. Thus, this work addresses the synthesis of a new class of biofoams consisting of starch (amylopectin) reinforced with LCNF from EFB, which were tested for their mechanical strength and water resistance.…”