Fiber chemistry — Cellulose is the principal constituent of most which type of fibers?

Introduction / Context:
Cellulose is a polysaccharide found in plant cell walls and is the foundation of many textile fibers. Understanding which fiber classes are cellulose-based helps in predicting moisture behavior, dyeing characteristics, thermal stability, and care instructions.

Given Data / Assumptions:

• The question contrasts cellulose-containing fibers with major synthetic families.
• Examples: cotton and flax (natural), viscose and lyocell (regenerated cellulose).
• Acrylics, spandex, and nylons are synthetic and not cellulose-based.

Concept / Approach:
Natural cellulosics (cotton, flax, jute, hemp) are primarily cellulose. Regenerated cellulose fibers (viscose rayon, modal, lyocell) are derived from cellulose dissolved and reprecipitated. In contrast, synthetic fibers like acrylic (PAN), spandex (polyurethanes), and nylon (polyamides) are petroleum-derived polymers.

Step-by-Step Solution:
Identify cellulose-containing classes: plant-derived natural fibers and regenerated cellulose.Exclude synthetic families: acrylics, spandex, nylons do not have cellulose backbones.Thus, the correct choice is natural (and regenerated) cellulose fibers.

Verification / Alternative check:
Textile references list cotton as ~90% cellulose, and rayon/lyocell as regenerated cellulose; acrylic and nylon contain no cellulose.

Why Other Options Are Wrong:

• Acrylic: PAN-based, nitrile groups, not carbohydrate.
• Spandex: segmented polyurethane; elastomeric, not cellulose.
• Synthetic in general: many are non-cellulosic.
• Nylon: polyamide chain, not carbohydrate.

Common Pitfalls:
Equating “natural” with “protein” (e.g., wool) instead of recognizing plant cellulosics; forgetting regenerated cellulose is still cellulose-based.

Final Answer:
Natural fibers (e.g., cotton, flax) and regenerated cellulose types