Chapter 13 - Polymer Materials | Classification of Polymers Flashcards
What are the 2 categories polymers can be classed into?
Synthetic & Natural polymers
What are the different chain structures of polymers?
Linear chains Branched chains Hyper branched polymer Cross linked polymer Net work polymer
What is a linear chain polymer?
a single continuous chain of repeat units
What is a branched chain polymer?
a polymer that includes side chains of repeat units connecting onto the main chain of repeat units
What is a hyper branched polymer?
consists of a constitutional repeating unit including branching groups
What is a cross linked polymer?
a polymer that includes interconnections between chains
What is a net work polymer?
a cross linked polymer that includes numerous interconnections between chains
Describe the polymer characteristics of a thermoplastic?
– Long chains with very limited or no cross-linking
– They behave in a plastic, ductile manner
– Melt when heated can be reversibly cooled & reheated, i.e. recycled
– heat till soft => shape as desired => cool
Describe thermoplastic amorphous?
randomly-oriented
Describe thermoplastic semicrystalline?
form layers of thin, chain-folded crystalline
lamellae separated by amorphous regions and
are connected with tie molecules
Describe the polymer characteristics of a thermoset plastic?
– Highly cross-linked
– Brittle (at most temperatures)
– Decompose when heated and can not easily be reshaped or recycled,
Describe the polymer characteristics of elastomers and rubbers?
- Large amounts of elastic deformation
- light cross-linking
- Crosslinks allows material to return to original shape without plastic deformation
How can you classify polymers according to their mer composition?
1) Homopolymers
2) Copolymers
What are Homopolymers?
A polymer consisting of one type of repeating unit
Name the 4 types of Copolymers?
- Statistical (random)
- Alternating
- Block
- Graft (chain of one type of polymer but branches of another type)
