Polymer Laboratory Mrs. Brostrom Integrated Science
Plastics • Plastics are not created equal because they are meant for different purposes • Protecting clothing • Storing food • Carrying groceries
Plastic bags are made from… • high-density polyethylene (HDPE) • grocery bags are HDPE • low-density polyethylene (LDPE) • garment bags from the dry cleaner are LDPE • linear low-density polyethylene (LLDPE) • thick, glossy shopping bags from the mall are LLDPE •The major difference between these three materials is the degree of branching of the polymer chain.
Shopping bags • Plastic wrap • Dry cleaning bag • Sandwich bag
Your Task • Design and conduct an experiment testing the physical properties of different types of plastic • You may choose between • Puncture resistance • Tensile strength • Abrasion reistance
Physical Properties of Plastics • HDPE and LLDPE are composed of linear chains • LDPE chains are branched • Branching can influence a number of physical properties including tensile strength • The more branched a molecule is, the lower is its tensile strength (dry cleaning bag)