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Chapter 9
Table 9.1
The Big Six
Polyethylene Polymer Recycle Symbol Polyethylene Polyethylene Polyethylene 4 Polyethylene Polyethylene Polyethylene Polyethylene Polyethylene 44 LDPE 44444 4 LDPE LDPE Polyethylene LDPE LDPE LDPE LDPE LDPE LDPE Polyethylene Polyethylene Polyethylene 2 Polyethylene Polyethylene Polyethylene Polyethylene Polyethylene
Ethylene H Monomer EthyleneH Ethylene Ethylene Ethylene Ethylene Ethylene Ethylene Ethylene C C HH HH
HHH HHH HH HH H H H CC CC H CCC CC CCC CC H C C HHEthylene H HHH HHH H H H H H H H EthyleneH Ethylene Ethylene Ethylene Ethylene Ethylene Ethylene Ethylene C C HH HH HHH HHH H H H H H C H H C CC H CCC C C C CC CC H C HH C H Vinyl chloride HHH HHH HH HH H H HVinyl chloride H Vinyl chloride Vinyl chloride Vinyl chloride HC Vinyl chloride Vinyl chloride Vinyl chloride C HH Vinyl chloride H HHH HHH H H H H H H H CC CC Cl CCC CC CCC CC Cl C C HH Cl Styrene HHH ClClCl H Cl H Cl H Cl H StyreneH Styrene Styrene Styrene Styrene Styrene Styrene C C HH HHStyrene HHH HHH HH C HH H H HC CC CCC C CCC CC C C HH C HHH H H H
22 2HDPE 22222 HDPE HDPE Polyvinyl chloride HDPE HDPE HDPE HDPE HDPE HDPE Polyvinyl chloride Polyvinyl chloride Polyvinyl chloride Polyvinyl chloride 3 Polyvinyl chloride Polyvinyl chloride Polyvinyl chloride Polyvinyl chloride 33or V PVC, 333333 PVC,ororVV PVC, Polystyrene PVC, ororor Vor PVC, PVC, PVC, VV PVC, or VV PVC, or V Polystyrene Polystyrene Polystyrene 6 Polystyrene Polystyrene Polystyrene Polystyrene Polystyrene 66 66PS 6666 PS PS PS PS PS PS PS PS
11 PETE, 11111 1 or PET PETE, PETE, orPET PET PETE, PETE, or PETE, PETE, PETE, PETE, ororor PET PET or PET PET or PET PET or
Uses of Polymer
Translucent if not pigmented. Soft and flexible. Unreactive to acids and bases. Strong and tough.
Bags, films, sheets, bubble wrap, toys, wire insulation.
Similar to LDPE. More rigid, tougher, slightly more dense.
Opaque milk, juice, detergent, and shampoo bottles. Buckets, crates, and fencing.
Variable. Rigid if not softened with a plasticizer. Clear and shiny, but often pigmented. Resistant to most chemicals, including oils, acids, and bases.
Rigid: Plumbing pipe, house siding, charge cards, hotel room keys. Softened: Garden hoses, waterproof boots, shower curtains, IV tubing.
Variable. “Crystal” form transparent, sparkling, somewhat brittle. “Expandable” form lightweight foam. Both forms rigid and degraded in many organic solvents.
“Crystal” form: Food wrap, CD cases, transparent cups. “Expandable” form: Foam cups, insulated containers, food packaging trays, egg cartons, packaging peanuts.
Opaque, very tough, good weatherability. High melting point. Resistant to oils.
Bottle caps. Yogurt, cream, and margarine containers. Carpeting, casual furniture, luggage.
Transparent, strong, shatterresistant. Impervious to acids and atmospheric gases. Most costly of the six.
Soft-drink bottles, clear food containers, beverage glasses, fleece fabrics, carpet yarns, fiber-fill insulation.
Propylene
Polypropylene Polypropylene Polypropylene Polypropylene Polypropylene 5 Polypropylene Polypropylene Polypropylene Polypropylene 55 PP 55555 5 PP PP PP PP PP PP PP PP Polyethylene terephthalate Polyethylene Polyethylene terephthalate Polyethylene Polyethylene terephthalate Polyethylene Polyethylene Polyethylene Polyethylene terephthalate terephthalate 1 terephthalate terephthalate terephthalate terephthalate
Properties of Polymer
HPropylene PropyleneH Propylene Propylene Propylene Propylene H Propylene Propylene C C HH H HHH HHH H H H H H C H H C CC CH3 CCC C C C CC CC CH C HH C CH3 3 glycol HEthylene CH H CH 3 3 HH CH CH HH CH CH 3 3333 HO Ethylene CH2CH OH Ethylene glycol 2 glycol Ethylene glycol Ethylene glycol Ethylene glycol CH HO CHCH OH Ethylene glycol Ethylene glycol Ethylene glycol HO CH OH 2 2 2 2 acid Terephthalic CH HO CH OH CH HO CH OH 2 2 2 2 CH CH HO HO CH CH OH OH CH HO CH CH OH CH HO OH 2 2222 2 2222 O Terephthalic Terephthalicacid acid O Terephthalic acid Terephthalic acid Terephthalic acid Terephthalic acid Terephthalic acid Terephthalic acidC OO OO C OOO OOO O O OO O O HO CC CC OH CC CCC CC CC OH C HOCC HO OH HO OH HO OH HO OH HO OH HO OH HO OH
Note: The structures of the first five monomers differ only by the atoms show in blue.
In contrast to thermoplastics, some plastics are thermosetting. These solidify or “set” irreversibly with heat. Examples include rubber-soled footwear and antique Bakelite ovenware.
© McGraw-Hill Education
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Table 9.1 also lists properties of these six polymers. All are solids that can be colored with pigments. All are also insoluble in water, although some degrade or soften in the presence of hydrocarbons, fats, and oils. All are thermoplastic polymers, meaning that with heat, they can be melted and reshaped over and over again. However, they exhibit a range of melting points depending on the route by which they were manufactured. Of the Big Six, polyethylene has the lowest melting point, with LDPE and HDPE melting at about 120 °C and 130 °C, respectively. In contrast, polypropylene (PP) melts at 160–170 °C. Depending on the arrangement of their molecules, polymers have varying degrees of strength. At the microscopic level, the molecules in some parts of the polymer may have an orderly repeating pattern, such as one would find in a crystalline solid (Figure 9.8). In these crystalline regions, the long polymer m olecules
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