GATE (TF) Textile 2015 Question Paper Solution | GATE/2015/TF/43

Question 43 (Textile Engineering & Fibre Science)

Consider the following assertion [a] and reason [r] and choose the correct alternative from amongst A, B, C and D.
[a] After polymerization of caprolactum, through washing of polymer with water is necessary to remove unreacted monomer and its oligomers.
[r] Otherwise, hydrolytic degradation of polymer would occur during melt spinning.

(A)[a] is right and [r] is wrong
(B)[a] is right and [r] is right
(C)[a] is wrong and [r] is wrong
(D)[a] is wrong and [r] is right
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Frequently Asked Questions | FAQs

What is obtained by the polymerization of caprolactam?

he polymerization of caprolactam results in the formation of nylon-6, which is a type of synthetic polyamide. Caprolactam is a cyclic monomer that contains six carbon atoms in its ring structure, hence the name “nylon-6.” During polymerization, caprolactam monomers undergo a process called ring-opening polymerization, wherein the ring structure of caprolactam is opened and the monomers link together through amide bonds to form a long chain polymer with repeating units of (-NH-(CH2)5-CO-)n, where n represents the number of monomer units in the polymer chain. Nylon-6, thus obtained, is a thermoplastic polymer with a wide range of applications due to its high strength, durability, and chemical resistance. It is commonly used in the manufacturing of fibers for textiles, carpets, and industrial applications, as well as in the production of molded parts, films, and coatings.

The polymerization of caprolactam typically involves the following steps:
Monomer preparation: Caprolactam, which is a cyclic monomer, is first purified to remove impurities and prepared for polymerization. This can involve processes such as distillation, crystallization, and drying to ensure that the caprolactam monomer is of high purity.
Initiator addition: Initiators, which are typically water or other chemicals, are added to the caprolactam monomer to initiate the polymerization reaction. Initiators help to break the ring structure of caprolactam and create reactive sites for polymerization.
Polymerization: The polymerization of caprolactam typically occurs through a process called ring-opening polymerization. Heat and/or pressure are applied to the monomer mixture, which causes the caprolactam rings to open and form reactive intermediates. These intermediates then react with other caprolactam monomers, forming covalent bonds and extending the polymer chain.
Chain growth: As the polymerization reaction progresses, the chain length of the polymer increases as more caprolactam monomers join the growing polymer chain through amide bond formation. The reaction continues until the desired molecular weight or polymer length is achieved.
Post-polymerization treatment: After the polymerization is complete, the resulting nylon-6 polymer may undergo post-polymerization treatment steps such as cooling, quenching, washing, and drying to remove residual monomers, initiators, and other impurities.

The exact conditions for the polymerization of caprolactam, including temperature, pressure, initiator type and concentration, and reaction time, can vary depending on the specific process and desired properties of the resulting polymer. Careful control of these parameters is important to achieve a high-quality nylon-6 polymer with the desired properties for its intended applications.

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