Fleece blanket
PET fibres make a soft, light blanket with an air-trapping raised surface.
Material
Polyester fleece fabric: PET
Material selection rationale
- Fine fibres
- Bend easily and form a soft fabric.
- Raised surface
- Holds still air between the fibres for warmth.
- Air held by the fabric
- The raised fibres reduce air movement within the fabric, so thickness and loft contribute to warmth beyond the polymer’s identity.
How it becomes a product
- Spin and knit: PET fibres are made into yarn and knitted into cloth.
- Raise and finish: Brushing raises the surface; the fabric is cut and its edges finished. Mechanical brushing lifts fibres from the textile surface; it alters the fabric structure without synthesising a different polymer.
Preparation routes
Terephthalic acid route
Esterification, then polycondensation. The acid and diol first form ester-linked intermediates, releasing water. Further reaction builds longer PET chains while small molecules are removed. Both feedstocks have two reacting ends, enabling repeated links rather than just one small ester. Balanced functional groups and extensive conversion are needed for long chains.
Industrial catalysts and controlled heating assist the reaction; they are not alternative monomers. Removing small-molecule products drives the reversible stages towards chain formation.
- Polyesters: manufacture and usesChemical Industry Education Centre, University of York
Dimethyl terephthalate route
Ester exchange, then polycondensation. The ester reacts with ethylene glycol, releasing methanol in the first stage. Further reaction builds PET chains. This complete input pair is an alternative to the acid route. Methanol identifies the initial ester-exchange route; the terephthalate and ethylene-glycol fragments retained in PET match those from the acid route.
Catalysts and heat support ester exchange and chain growth; excess glycol and other small molecules are removed as the process proceeds. Feedstock substitution changes the reaction sequence and by-products, not the required two-ended glycol.
- Polyesters: manufacture and usesChemical Industry Education Centre, University of York
From p-xylene to terephthalic acid
- p-Xylene + Oxygen from air → Terephthalic acid
Catalytic air oxidation changes both methyl groups into carboxylic acid groups while retaining their opposite positions on the benzene ring. Acetic acid is the process solvent, not an extra carbon fragment in terephthalic acid. Recovery, purification and crystallisation produce the purified diacid used in polyester manufacture.
From ethene through ethylene oxide to ethylene glycol
- Ethene + Oxygen + Water → Ethylene glycol
First, catalytic partial oxidation converts ethene to ethylene oxide, a three-membered epoxide. In the selected thermal route, water then opens the oxide ring to form ethylene glycol. Heavier glycols also form and are separated. The two-carbon unit reaches PET through a diol, unlike the direct addition polymerisation of ethene into polyethylene.
Sources
- THORGUN polyester fleece throwIKEA
- Polyesters: manufacture and usesChemical Industry Education Centre, University of York