Cellulose and Hemicellulose Lecture Review

A series of vocabulary flashcards based on key concepts related to cellulose, hemicellulose, and their properties.

Cellulose I

Naturally occurring crystalline form of cellulose with two forms: Iα (metastable, triclinic) and Iβ (more stable, monoclinic).

Cellulose II

Man-made cellulose formed from cellulose I via processes like mercerization or regeneration; lower crystallinity than cellulose I.

Mercerization

A process involving the treatment of cellulose I with 18% NaOH, transforming it into Na-cellulose.

Cellulose III

Formed from cellulose I or II treated with liquid ammonia; includes two types: IIII (non-reversible) and IIIII (reversible).

Hemicellulose

Polysaccharide component of plant cell walls that provides structural support and is cross-linked with cellulose.

Softwood Hemicellulose

Primarily galactoglucomannan (about 20%) with minor amounts of arabinoflucuronoxylan (about 5-10%).

Hardwood Hemicellulose

Primarily glucuronoxylan (about 30%) with minor amounts of glucomannan (about 2-5%).

Solvent Extraction

The first step in isolating cellulose and hemicelluloses from wood, producing extractive-free wood.

Holocellulose

The insoluble product obtained after treating extractive-free wood with NaClO2, acetic acid, and heat.

Monolignols

Alcohols that serve as building blocks for lignin, with variations in types between gymnosperms, dicotyledons, and monocotyledons.

Deamination

The conversion of phenylalanine to cinnamic acid, the first step in monolignol biosynthesis.

Glycosylation

A process that increases the solubility of monolignols by adding sugar moieties.

Beta-O-4 Linkage

A type of bond formed during lignin polymerization involving coniferyl alcohol molecules.

Extractives

Natural compounds found in wood that can impact the properties of pulps and paper, including turpentine and rosin.

Terpenes

Compounds formed from the condensation of isoprene units, significant in forming resinous materials.

Aliphatic Compounds

A group of extractives that includes alkanes, fatty alcohols, fats, and waxes.