Molecular Origin Of Polymer Flashcards
Molecules that have double, and triple covalent bonds that is each carbon atom is not bonded to the maximum (four) other atoms.
Unsaturated Molecules
All bonds are single ones, and no new atoms may be joined without the removal of others that are already bonded.
Saturated Molecules
A molecule that combines with other molecules of the same or different type to form a polymer.
Monomer
A low molecular weight polymer that contains at least two monomer units.
Oligomer
It specifies the length of the polymer molecule.
Degree of Polymerization
A dimensionless quantity given by the sum of the atomic weights in the molecular formula.
Molecular Weight
Enumeration.
Classification of Polymers.
- Based on Origin
- Based on Polymer Structure
- Based on Polymerization Mechanism
- According to Thermal Processing Behavior
- Based on Preparative Technique
Enumeration.
Classification of Polymers based on origin.
- Natural
- Synthetic
What does PET stands for?
Polyethylene Terephthalate
What does HDPE stands for?
High-density Polyethylene
What does PVC stands for?
Polyvinyl Chloride
What does LDPE stands for?
Low-density Polyethylene
What does PP stands for?
Polypropylene
What does PS stands for?
Polystyrene
Enumeration.
4 Classification based on Polymer structure.
- Linear
- Branched
- Cross-linked
- Network
Comparison.
Linear, Branched, Cross-linked, Network
- Linear Polymers are those in which the repeat units are joined together end to end in single chains. These long chains are flexible and may be thought of as a mass of “spaghetti”.
- Branched Polymers have side chains or branches growing out from the main chain. The side chains or branches are made of the same repeating units as the main polymer chains.
- In cross-linked polymers, adjacent linear chains are joined one to another at various positions by covalent bonds. Crosslinks are tend to be permanent in nature.
- Network Polymers are multifunctional monomers forming three or more active covalent bonds make three dimensional networks.
Enumeration.
Classification based on Polymer structure.
- Amorphous
- Crystalline
Comparison.
Amorphous, Crystalline.
- Amorphous polymers are polymers that have no crystalline regions and no uniformly packed molecules.
- Crystalline polymers exhibits a highly-ordered molecular structure, resulting in a repeating three-dimensional arrangement known as crystalline lattice.
A measure of the degree of order or orientation in a crystal.
Degree of Crystallinity
Enumeration.
2 Classification Based in Polymer Structure (Monomer Composition).
- Homopolymer
- Copolymer
When all of the repeating units along a chain are of the same type.
Homopolymer
A polymer made up of more than one type of monomer unit.
Copolymer
Representing two different mers by A and B.
Random Copolymer
The two mers alternate in a regular fashion along the polymer chain.
Alternating Copolymer
A linear polymer with one or more long uninterrupted sequences of each mer in the chain.
Block Polymer
A branched copolymer with a backbone of one type of mer and one or more side chains of another mer.
Graft Copolymer
Enumeration.
3 Classification based on Polymer structure.
- Fibers
- Plastics
- Elastomers
Linear polymers with high symmetry and high intermolecular forces that result usually from the presence of polar groups.
Fibers
Molecules with irregular structure, weak intermolecular attractive forces, and very flexible polymer chains.
Elastomers
A polymer typically modified with additives which can be molded or shaped under reasonable conditions of pressure and temperature.
Plastic
What does O stands for?
Bisphenol A
Enumeration.
Classification based on Polymerization Mechanism.
- Condensation Polymers
- Addition Polymers
Formed from a series of reactions, often of condensation type, in which any two species can react at any time leading to a larger molecule.
Condensation Polymers
Produced by reactions in which monomers are added one after another to a rapidly growing chain.
Addition Polymers
Enumeration.
Classification of Polymers according to thermal processing behavior.
- Thermoplastics
- Thermosets
Comparison.
Thermoplastics, Thermosets.
- Thermoplastics are plastics that soften when heated and become firm again when cooled. The heating and cooling may be repeated and the thermoplastic may be reformed.
- Thermosets are plastics that soften when heated and can be molded but harden permanently. They decompose when reheated.
Enumeration.
Classification based on Preparative Technique.
- Bulk Polymerization
- Solution Polymerization
- Suspension Polymerization
- Emulsion Polymerization
Polymerization where only the monomer (and possibly catalyst and initiator, but no solvent) is fed into the reactor.
Bulk Polymerization
It involves the polymerization of a monomer in a solvent in which both the monomer (reactant) and the polymer (product) are soluble.
Solution Polymerization
It refers to the polymerization in an aqueous medium with the monomer as the dispersed phase.
Suspension Polymerization
Similar to suspension polymerization, but the initiator is located in the aqueous phase (continuous phase) in contrast to the monomer (dispersed phase) in suspension polymerization.
Emulsion Polymerization
Enumeration.
Bulk Properties of Polymers.
- Tensile Strength
- Young’s Modulus of Elasticity
- Transport Properties
- Pure Component Phase Behavior
Quantifies how much stress the material will endure before failing.
Tensile Strength
Quantifies the elasticity of the polymer.
Young’s Modulus of Elasticity
The ratio of rate of change of stress to strain.
Young’s Modulus of Elasticity.
A transition from a crystalline or semi-crystalline phase to a solid amorphous phase.
Melting Point
A crucial physical parameter for polymer manufacturing, processing, and use.
Glass Transition
