Chapter 3 L08 Flashcards
What is a thermoset?
- It is a type of polymer that once cured or hardened cannot be metled or reshaped
- They have high mechanical performance at high temperatures
Name some general properties of thermosets
- Small portion of plastics
- Covalent bonds linking chains. Heat breaks this bonds
- This material is created through varius chemical reactions with different components
Name one representative of mass, technical and high performance thermoplastics
- Mass plastic: Urea Resin
- Technical plastic: Epoxy Resin
- High performance plastic: Polyimides
What are the typical components of thermosets?
- Resin
- Curing agent
- Accelerator or Inhibitor
Name mechanical properties of thermosets
- Advantages: Resistance to creep, Good fatigue properties
- Disadvantages: Limited lifetime, difficult to recycle
Where can thermosets be found in everyday life?
Bicycle frame, chipboard (aglomerado, “madera”)
Draw and label the temperature and viscosity curve during the curing process
“Notes”
Explain what curing is and the steps of the process
- Curing refers to the process of hardening or solidifying a material.
- It is used to achive some mechanical properties
Notes
Label the different ranges in the TTT diagram
“Notes”. Time-Temperature-Transition
What does DoC mean?
Degree of Cure.
100% DoC means that all the resin and hardener have reacted.
Name properties of epoxy resins and one trade name
- Properties: Resistent to water and other liquids
- Trade name: Epikote
Name properties of phenolic resins and one trade name
- Properties: Low creep deformation
- Trade name: Resinol
Name properties of polyimides resins and one trade name
- Properties: Highest heat resistance
- Trade name: PBI
Name properties of unsaturated polyester resins and one trade name
- Properties: Weather resistant
- Trade name: Atlac
Difference between curing and vulcanization
- Curing: Hardening or solidifing a material to achieve desired mechanical properties
- Vulcanizing: Enhance material properties of RUBBER
