Mr. Rogers' IB Design Technology Objectives
Plastics - thermoplastics or thermosets
  1. Describe a covalent bond.

  • outer electrons of atoms come close enough to overlap and are shared between the nuclei,

  • each pair of electrons is called a covalent bond.

  • strong bonds

  1. Describe the structure and bonding of a thermoplastic.

  • Longchains called polymers of a repeating molecule called a monomer

  • chains can be linear or have either short or long chain branches

  • Chains have some folding or coiling

  • Bonding within the chain: covalent

  • Bonding between chains: weak bonds

  1. Describe the effects of load on a plastic or polymer

  • elastic region: the chains ten to straighten or uncoil like tiny springs

  • plastic region: adjacent molecules slide past each other

  • temperature effect: increased temperature favors plastic deformation

  1. Draw and describe the structure and bonding of a thermoset.

Thermoplastic Examples (thermoplastics can generally be recycled.)
Plastic Application
polyethylene plastic bags
polypropylene rope

PVC (polyvinyl chloride)

vinyl siding,  pipe, upholstery,  flexible hoses
PET (Polyethylene terephthalate) drink bottles


Thermosetplastic Examples (thermoplastics generally cannot be recycled)

Plastic Application
urea–formaldehyde adhesives, finishes, MDF, and molded objects
epoxy adhesives, molded parts, coatings


foam padding, wear resistant parts