2A Polyester

Question 1

How is polyester made?

Answer 1

1. derived from oil in the form of PETROCHEMICALS
2. processed into a POLYMER substance which is cut into CHIPS
3. melted in the SPINNING process and EXTRUDED as polyester fibres
4. Forms: flat filament/textured filament/staple fibre

Question 2

Features of polyester fibres

Answer 2

• non-renewable fibre/not biodegradable
• can be recycled easily
• can be engineered to suit specific end-uses/properties (e.g. flat filaments: cool to wear or textured filaments: insulation)
• texture and thickness varies (microfibre/fine/soft to coarse/firm)

Question 3

Properties of polyester fibres (8)

Answer 3

• strong/durable (excellent abrasion and tear resistance)
• good elasticity and crease resistance
• resistant to alkalis/solvents/mould/mildew
• lightweight
• hydrophobic (water repellent)
• thermoplastic: can be permanently shaped using heat
• not resistant to prolonged exposure to sunlight (can cause fibres to lose strength)
• not absorbent/prone to static (some textured filaments can wick away moisture)

Question 4

Finishes (polyester)

Answer 4

• flame-resistant
• anti-static treatment
• others: specific to end-use

Question 5

Blends (polyester)

Answer 5

• staple fibres: wool/cotton/viscose/modal/linen/silk
• common blend ratios: 70/30, 65/35, 55/45, 50/50

Question 6

Fabrics (polyester)

Answer 6

• microfibre fabrics
• Dacron®
• Trevira®
• Hollofil

Question 7

End-uses (polyester)

Answer 7

• clothing
• ties
• scarves
• rainwear
• lining
• net curtains

Question 8

After care (polyester)

Answer 8

• machine washable
• low temp.
• dries quickly
• iron with care
• can be dry cleaned/tumble dried
• no bleaching

Question 9

Testing (polyester)

Answer 9

Burning:
- melts and shrinks away from the flame
- forms a brownish mass which can drip
Residue:
- hard/solid