MMET 201 FINAL EXAM LATEST
2 Types of Failure - ANSWERS-Fracture(ductile, brittle) and Buckling
Residual Stresses are stresses that - ANSWERS-remain within a part
after it has been deformed plastically non uniformly and all external
forces have been removed
can be caused by temperature gradients within the body
Reduction of residual stresses is made by - ANSWERS-Stress relief
annealing or by further deformation, or relaxation of residual stresses at
room or elevated temperature
Why polymers have a lot of applications: - ANSWERS-Relatively low
cost
Corrosion resistance and resistance to chemicals
Low electrical and thermal conductivity
Low density
High strength to weight ratio
Noise reduction
Ease of manufacturing
END OF
PAGE
1
, MMET 201 FINAL EXAM LATEST
Properties of molecules are determined by - ANSWERS-which atoms,
how many, and how they are bonded
properties of bulk material determined by - ANSWERS-molecules
Molecule is a combination of - ANSWERS->= 2 atoms
Polymers are - ANSWERS-long chain molecules that are formed by
polymerization which is linking and crosslinking of monomers
Monomer is - ANSWERS-the basic building block of the polymer
Degree of Polymerization (DP) - ANSWERS-the ratio of the molecular
weight of the polymer to the molecular weight of the repeating unit
The higher the DP, the higher the _________ of the polymer -
ANSWERS-viscosity
Primary types of chemical bonds (3) - ANSWERS-Covalent bonds
Metallic bonds
END OF
PAGE
2
, MMET 201 FINAL EXAM LATEST
Ionic bonds
What is called the backbone of polymer chain - ANSWERS-carbon
atoms
Linear Polymers definition + is it easy to break? - ANSWERS-
Thermoplastics such as acrylics, nylon, PVC, and polyethylene
Easy to break
Branched Polymers definition + is it easy to break? - ANSWERS-
polyethylene
Easy to break
Cross-Linked Polymers definition + is it easy to break? - ANSWERS-
Elastomers such as rubber
Not easy to break
Network Polymers definition + is it easy to break? - ANSWERS-they
are highly cross linked structures: Thermosets such as epoxies and
phenolic
Some easy to break
END OF
PAGE
3
, MMET 201 FINAL EXAM LATEST
Plastics are made of repeating structures of carbon, hydrogen, and other
elements called - ANSWERS-mers
n times mer mass determines molecular mass - affect properties. What
does it increase? (2) - ANSWERS-Increases elongation and tensile
strength at rupture
Increases melt viscosity and impact strength
Homopolymers - ANSWERS-the simplest chemical plastics, only one
basic structure
Copolymers (3) - ANSWERS-Block Copolymer - 2 v 2
Alternating Copolymer - 1 v 1
Random Copolymer - completely random
Terpolymers have 3 different ____ and 4 different structures can occur...
- ANSWERS-mers
alternating, random, block, and graft structures
Molecular Organization - ANSWERS-arrangement of molecules
END OF
PAGE
4
2 Types of Failure - ANSWERS-Fracture(ductile, brittle) and Buckling
Residual Stresses are stresses that - ANSWERS-remain within a part
after it has been deformed plastically non uniformly and all external
forces have been removed
can be caused by temperature gradients within the body
Reduction of residual stresses is made by - ANSWERS-Stress relief
annealing or by further deformation, or relaxation of residual stresses at
room or elevated temperature
Why polymers have a lot of applications: - ANSWERS-Relatively low
cost
Corrosion resistance and resistance to chemicals
Low electrical and thermal conductivity
Low density
High strength to weight ratio
Noise reduction
Ease of manufacturing
END OF
PAGE
1
, MMET 201 FINAL EXAM LATEST
Properties of molecules are determined by - ANSWERS-which atoms,
how many, and how they are bonded
properties of bulk material determined by - ANSWERS-molecules
Molecule is a combination of - ANSWERS->= 2 atoms
Polymers are - ANSWERS-long chain molecules that are formed by
polymerization which is linking and crosslinking of monomers
Monomer is - ANSWERS-the basic building block of the polymer
Degree of Polymerization (DP) - ANSWERS-the ratio of the molecular
weight of the polymer to the molecular weight of the repeating unit
The higher the DP, the higher the _________ of the polymer -
ANSWERS-viscosity
Primary types of chemical bonds (3) - ANSWERS-Covalent bonds
Metallic bonds
END OF
PAGE
2
, MMET 201 FINAL EXAM LATEST
Ionic bonds
What is called the backbone of polymer chain - ANSWERS-carbon
atoms
Linear Polymers definition + is it easy to break? - ANSWERS-
Thermoplastics such as acrylics, nylon, PVC, and polyethylene
Easy to break
Branched Polymers definition + is it easy to break? - ANSWERS-
polyethylene
Easy to break
Cross-Linked Polymers definition + is it easy to break? - ANSWERS-
Elastomers such as rubber
Not easy to break
Network Polymers definition + is it easy to break? - ANSWERS-they
are highly cross linked structures: Thermosets such as epoxies and
phenolic
Some easy to break
END OF
PAGE
3
, MMET 201 FINAL EXAM LATEST
Plastics are made of repeating structures of carbon, hydrogen, and other
elements called - ANSWERS-mers
n times mer mass determines molecular mass - affect properties. What
does it increase? (2) - ANSWERS-Increases elongation and tensile
strength at rupture
Increases melt viscosity and impact strength
Homopolymers - ANSWERS-the simplest chemical plastics, only one
basic structure
Copolymers (3) - ANSWERS-Block Copolymer - 2 v 2
Alternating Copolymer - 1 v 1
Random Copolymer - completely random
Terpolymers have 3 different ____ and 4 different structures can occur...
- ANSWERS-mers
alternating, random, block, and graft structures
Molecular Organization - ANSWERS-arrangement of molecules
END OF
PAGE
4
