Unit 2 - Lecture 11 Topic 1

Question 1

Synthetic Fibers:

Answer 1

Fibres made from synthetic polymer that are made from basic raw materials. They are often petrochemicals and make up a huge industry, but <1% of all petroleum-based products used annually are used to make fibres. Synthetic fibres cover a vast array of properties and
characteristics.

Question 2

Addition Polymerization:

Answer 2

Double bonds broken, reforms as a single bonds connecting 2
repeating units.

Question 3

Condensation Polymerization:

Answer 3

As monomers combine, water or another small molecule is formed as a by-product.

Question 4

What are the most common synthetic fibres?

Answer 4

Nylon, polyester, olefin, acrylic.

Question 5

What do synthetic fibres have a negative reputation?

Answer 5

They’re involved in environmental impacts, poor comfort, and bad fast
fashion.

Question 6

Why are synthetic fibres good?

Answer 6

They are versatile, easy to care for, durable, and high-tech.

Question 7

What are the two common manufacturing processes with synthetic fibres?

Answer 7

Melt spun, heat set or drawn.

Question 8

What is melt spinning used for?

Answer 8

Used for most synthetics

Question 9

Why are some synthetics drawn?

Answer 9

To develop strength, pliability, toughness,
and elasticity properties

Question 10

Why are synthetics commonly heat set? How?

Answer 10

To stabilize yarns or fabrics. Filaments are heated up to glass transition temperature
(depends on fibre type). Molecules move freely at this temperature and they are held under tension until cooled. Fabric will be stable to any temperature
lower than heat set temperature.