polymer

• •Long polymer chains undergo chain entanglement

  •Hard, rigid, and brittle at low temperature

  •Turns into rubbery state at intermediate temperature

  •Elasticity à Entanglement allows material to retain its shape after application of stress
• •Cooperativity of Intermolecular Forces

  •Increase of intermolecular force due to multiplication of interaction points in polymers

  •Polymer crystals are very hard and have high tensile strength, and less soluble
• •Homopolymers:Polymers that are made of a single type of monomer (e.g. PE, Teflon, etc)

  •Copolymers:Polymers made of a mixture of more than one type of monomer (e.g. SBR, Polyurethane)•
• •Thermoplastics

  •Undergo physical transition at higher temperature from hard to soft, and eventually “liquid” form

  •Makes up the bulk of industrial polymer for daily use

  •Can be recycled

  •Usually consists of single strands of polymer chains
• •Thermosets

  •Polymer materials that do not melt

  •Cannot be recycled

  •Produced by 3D crosslinking of polymer chains after molded