How do polymers arrange themselves in fiber?
The polymers after being bonded to the molecules arrange or orient themselves in the fiber. But first, let us understand certain points related to the fiber polymer system:
• The ratio of the area that the amorphous and crystalline region covers also differs.
• The difference in the presence of amorphous and crystalline regions contributes to the specific properties of the fiber.
• The ratio of the area that amorphous and crystalline arrangement varies in natural fibers during their growth.
• The proportion of area amorphousness and crystallinity in regenerated fibers can be controlled during their processing.
The polymers arrange themselves in broadly two manner:
1. Amorphous Arrangement: When the polymers are lying in a random manner or exhibit no specific order, it is called amorphous region or arrangement. Due to the presence of random arrangement, the polymers can move easily when stressed and strain.
Features of amorphous arrangement are 1. Better water absorbent and dye uptake due to larger spaces 2. Lower interpolymer forces of attraction 3. Lower chemical resistance 4. Soft handle and easily blended 5. Less durable 6. More plastic
2. Crystalline Arrangement:
The polymers may be arranged in parallel bundles exhibiting more order are called crystalline arrangement or region. However, when the bundles of fibers are not only parallel to each other but also to the longitudinal axis of the fiber are referred to as oriented arrangements.
Features of crystalline arrangement are 1. Less water absorbent and dye uptake 2. Strong internal forces 3. High chemical resistance 4. Stiff handle 5. More durable 6. Less plastic.
When we discuss the orientation of polymers in fibers, an important point that emerges very often is that the arrangement of polymers in natural fibers is still not known while in case of regenerated fibers the orientation is controlled during the fiber processing step i.e. drawing that stretches the extruded filament which in turn causes the polymer to arrange themselves in parallel order.