Properties of plastic

Compare and contrast thermoplastic and thermset polymers

Thermplastics are plastics that soften when heat and harden when cooled, chan is held together by intermolecular forces having low melting point ideal for recyled materials

Thermosetting plastics are polymers that permantely harden when heated. Once set they cannot be melted reshaped or remoulded due to crosslinking between polymer chains (covalent bond), used for situations where heats a factor like electronic housings

Outline the difference between LDPE and HDPE

Polyethylene has tw commerical forms, hgih density polyethylene and low density polyethene

• LDPE branches ins tructure = mroe felxible, HDPE is more linear = more rigid

Describe what is meant by the term amorphous

Amorphous polymers have radomly arranged molecular chains,

Proeprties no sharp melting point and gradually soften as temp increases

E.g natural rubber latex

Describe what is meant by the term crystalline

Orderly stacks of folded chains called lamellae

High mechanical strength and stiffness

e.g HDPE and Polypene, Nylon