Question

Tenacity of polynosic in g/den

• A. 3.5--4.5
• B. 8--8.5
• C. 2--3
• D. 1--2

Hint:

Polynosic fibres bridge the gap between regular viscose and high-tenacity rayon in terms of strength.

Answer 1

The Correct Option is A

Step 1: Understanding polynosic fibre.
Polynosic fibre is a modified viscose rayon with higher crystallinity and molecular orientation compared to regular viscose.
Step 2: Effect on strength.
Due to improved structural order, polynosic fibres exhibit higher tenacity than ordinary viscose rayon.
Step 3: Typical tenacity values.
The standard tenacity range of polynosic fibres lies between 3.5 and 4.5 g/den.
Step 4: Conclusion.
Hence, the correct tenacity range of polynosic fibre is 3.5--4.5 g/den.

Answer 2

Polynosic is a modified, high-performance form of viscose rayon, so its tenacity should be checked against both ordinary viscose rayon and much stronger synthetic fibres, to see which range fits its actual position between the two.

1. 3.5-4.5 g/den: This is noticeably higher than ordinary viscose rayon's typical tenacity (around 2-2.5 g/den) but still well below high-tenacity synthetic fibres, which matches polynosic's role as an improved, higher-crystallinity regenerated cellulose fibre rather than a fully synthetic high-strength fibre.
2. 8-8.5 g/den: This is in the range of high-tenacity synthetic fibres such as high-tenacity polyester or nylon industrial yarns, far beyond what a modified cellulose fibre like polynosic achieves.
3. 2-3 g/den: This range describes ordinary viscose rayon rather than the improved polynosic variant; polynosic is specifically engineered to exceed this baseline through higher crystallinity and orientation.
4. 1-2 g/den: This is even weaker than ordinary viscose rayon and would be unusually low for any commercial textile fibre used in apparel or industrial application, making it inconsistent with polynosic's improved structure.

Positioned above ordinary viscose but well below synthetic high-tenacity fibres, polynosic's tenacity falls in the moderate-improved range.

Therefore, the correct answer is 3.5-4.5 g/den.