Plastics, Polymers and Composites Flashcards
What is the main difference between thermosets and thermoplastics?
Thermosets retain their form whereas thermoplastics can melt under heat after curing
How are thermoplastic and thermosets polymer structures different?
Thermoplastic: weak intermolecular forces between polymer chains, no cross-links
Thermoset: strong covalent bonds between polymer chains
What does it mean when thermoplastics become soft when heated due to crossing the “glass transition temperature” (Tg)?
The temperature at which a polymer changes from a hard state to a soft state
What are some examples of thermoplastics?
Polyethylene (PE)
Polycarbonate (PC)
Polyvinyl chloride (PVC)
What are some examples of thermosets?
Polyester resin
Polyurethanes
Bakelite
What are Fibre-Reinforced Polymers (FRPs)?
Composites made from a polymer matric reinforced with another material (a matrix)
What is an elastomer?
A material with loosely crosslinked polymers, examples being rubber and neoprene
What does composites being “anisotropic” mean?
The material properties change depending on the placement and number of layers of reinforcement material (fibres)
What is flexural strength?
A material’s ability to withstand bending
What are some composite properties?
Tensile strength
Shear strength
Compressive strength
What are some examples of composites?
MDF
Plywood
GRP
CRP (Carbon fibre Reinforced Plastic)
