Page 15 - Shawl Weaving Artisan - TT

Procedure Limitations of burn test: Blended fabrics can be difficult
to identify, and finishes applied to fabrics can alter burning
1 Isolate a few threads from the warp and weft directions
of the fabric (as blends might have different fibers). characteristics.
3 Microscopic examination (Fig 3)
2 Hold the threads with tweezers and slowly bring them
towards a small flame (e.g., a candle or lighter).
3 Observe the fiber’s reaction near the flame, in the
flame, and after being removed from the flame.
4 Note the odor of the smoke and the appearance of
the ash.
Typical reactions
• Cellulosic fibers (Cotton, Linen, Rayon, Viscose)

- Near flame: Ignites quickly.
This is a more precise and reliable method, especially
- In flame: Burns rapidly with a yellow flame. for natural fibers, as they have distinct morphological
- Removed from flame: Continues to burn, often features under a microscope.
with an afterglow. 1 Prepare a slide with a few individual fibers, mounted

- Odor: Burning paper, wood, or leaves. in water or mineral oil.
- Ash: Fine, feathery, grey ash, easily crushed. 2 Examine under varying magnifications (100x to 400x).
- Linen burns slower than cotton and rayon. 3 Observe both longitudinal and cross-sectional views.
• Protein fibers (Wool, Silk) • Key features to look for

- Near flame: Curls away from the flame, shrinks. • Longitudinal view
- In flame: Burns slowly, often sputtering, may self- • Cotton: Flat, twisted, ribbon-like with convolutions.
extinguish (especially wool). • Linen (Flax): Straight, rod-like with nodes

- Removed from flame: Stops burning or burns (bamboo-like joints).
very slowly.
• Wool: Scaly surface (overlapping epidermal
- Odor: Burning hair, feathers, or charred meat. scales), crimped, sometimes with a medulla
(central canal).
- Ash: Black, brittle, crushable bead (wool) or black,
shiny, irregular bead (silk), easily powdered. • Silk: Smooth, translucent, rod-like, often irregular
in width.
• Synthetic fibers (Polyester, Nylon, Acrylic,
Spandex) • Rayon (Viscose): Uniform diameter with
longitudinal striations.
- Near flame: Melts, shrinks, or curls away from the
flame. • Polyester/nylon: Smooth, uniform, rod-like
(can be trilobal, dog-bone, etc., depending on
- In flame: Melts and drips (polyester, nylon) or manufacturing).
sputters (acrylic).
• Acrylic: Smooth, uniform, sometimes with a dog-
- Removed from flame: Polyester and nylon often
continue to melt and drip; acrylic continues to burn bone shape.
with a smoky flame. • Cross-sectional view

- Odor: Chemical, plastic, sweet (polyester), celery • Cotton: Kidney-bean or flat, irregular shape with
(nylon), fishy (nylon), acrid (acrylic). a lumen (central canal).
- Ash: Hard, shiny, often spherical bead (polyester, • Linen: Polygonal with a small lumen.
nylon), irregular, hard black bead (acrylic). The • Wool: Oval to circular, sometimes with a medulla.
bead is usually difficult or impossible to crush.
• Silk: Triangular or irregular round.
• Acetate
• Rayon (Viscose): Irregular, serrated, or scalloped
- Near flame: Melts and shrinks.
edges.
- In flame: Melts, drips, and burns with a yellow, • Polyester/nylon: Often round, but can be trilobal,
flickering flame. multi-lobed, etc., depending on the spinneret
- Odor: Vinegar-like. shape.

- Ash: Hard, brittle black bead.

Textile & Handloom: Shawl Weaving Artisan : (NSQF - 2024) R.T. Ex.No 1.1.02&07 5