Understanding plastic identification codes

Plastic identification code	Type of plastic polymer	Properties	Common packaging applications	Melting- (°C) and glass transition temperatures	Young’s modulus (GPa)
	Polyethylene terephthalate (PET, PETE)	Clarity, strength, toughness, barrier to gas and moisture.	Soft drink, water and salad dressing bottles; peanut butter and jam jars; small consumer electronics	Tm = 250;[43] Tg = 76[43]	2–2.7[44]
	High-density polyethylene (HDPE)	Stiffness, strength, toughness, resistance to moisture, permeability to gas	Versatility, ease of blending, strength, toughness.	Blister packaging for non-food items; cling films for non-food use. May be used for food packaging with the addition of the plasticisers needed to make natively rigid PVC flexible. Non-packaging uses are electrical cable insulation; rigid piping; vinyl records.	0.8[44]
	Polyvinyl chloride (PVC)		Ease of processing, strength, toughness, flexibility, ease of sealing, barrier to moisture	Frozen food bags; squeezable bottles, e.g. honey, mustard; cling films; flexible container lids	2.4-4.1[49]
	Low-density polyethylene (LDPE)		Strength, toughness, resistance to heat, chemicals, grease and oil, versatile, barrier to moisture.	Reusable microwaveable ware; kitchenware; yogurt containers; margarine tubs; microwaveable disposable take-away containers; disposable cups; soft drink bottle caps; plates.	0.17–0.28[49]
	Polypropylene (PP)		Versatility, clarity, easily formed	Egg cartons; packing peanuts; disposable cups, plates, trays and cutlery; disposable take-away containers	1.5-2[44]
	Polystyrene (PS)		Dependent on polymers or combination of polymers	Beverage bottles, baby milk bottles. Non-packaging uses for polycarbonate, compact discs, “unbreakable” glazing, electronic apparatus housing, lenses (including sunglasses), prescription glasses, automotive headlamps, riot shields, instrument panels.[53]	3-3.5[44]
	Other (often polycarbonate or ABS)			Polycarbonate: Tg = 145;[54] Tm = 225[55]	Polycarbonate: 2.6;[44] ABS plastics: 2.3[44]