Post on 20-Jan-2016
Polymer Chemistry
Polymer Characteristics
and ClassificationsMs. MandelHonors Physical Science
D15
OExplain the general formation and structure of carbon-based polymers, including synthetic polymers, such as polyethylene, and biopolymers, such as carbohydrate.
D16OExplain how simple chemical
monomers can be combined to create linear, branched and/or cross-linked polymers.
D17OExplain how the chemical
structure of polymers affects their physical properties.
Learning TargetsLearning TargetsOI can explain how the structure
of a polymer affects its properties.
OI can differentiate between thermoset and thermoplastic polymers.
OI can explain how polymers are synthesized.
Polymers
OWhat is a Monomer?O The individual units that join together to
form a polymer. OWhat is a Polymer?
O A very long molecule composed of repeating units connected by covalent bonds.
Characterizing a Polymer
O Structure O Classification O Synthesis
Structure of a PolymerO Skeletal Structure O Chemical Structure
Skeletal StructureOLinear
O A straight chain with two ends
Linear StructureLinear StructureOWhat properties might a linear
structure produce?O Short and long chains
O Long molecules can get tangled up in each other and stick together better
O Long molecules are harder and have higher melting points
O Short chains pass over each other easily and are softer and “squishy”
O No side chains means it has a higher density because more molecules can pack into the same amount of space
O The molecules can slide over each other more easily if there is nothing in the way to stop themO Stretchy
Skeletal StructureOBranched
O Have side chains
Branched StructureBranched Structure
OWhat properties might a branched structure produce?O If chains are branched then they
cannot pack close together = low density
O Branches catch on each other, preventing chains from sliding past one other
O Plastic is less stretchy
Skeletal StructureOCross-linked
O Chains are connected to other chains
Cross-Linked StructureCross-Linked StructureOWhat properties might cross-linking
produce?O Chains permanently connected to each
otherO Makes the material stronger and harder
OVulcanizationO Degree of cross-linking determines
stretchiness
rubberpump.com
•No chains linked together
•Larger range of motion available to chains more bouncy
•Chains linked together
•Increasing stiffness
•Less range of motion available rigid and stiff
Identify the following polymers:
Learning Target Learning Target CheckpointCheckpoint
O How does structure determine the property of a polymer?
Chemical Structure
OHomopolymerO Only one monomer
- A – A – A – A – A – A – A -
Chemical StructureOCopolymer
O More than one monomer
ClassificationsO ThermoplasticO ThermosetO Elastomer
ThermoplasticsOLinear or branched polymersOCan be melted when heat is applied OCan be molded into any shape with
processing techniques OCommonly known as “plastics”
www.mr-dt.com
Thermoplastics
OExamples: bottles, grocery bags, water piping, rope, fishing line, car parts, etc.OMost are
recyclable www.petervaldivia.com
Plastic Resin Codes
mjacobandsons.com
ThermosetsONormally are rigid materials ONetwork polymers in which chain
motion is greatly restricted by a high degree of crosslinking
OCannot be reshaped once formed
www.mr-dt.com
ThermosetsOExamples: super
glue, counter top laminates, tires (vulcanized rubber)
OCannot be recycled (burn/scorch with heat)
www.stephensinjectionmoulding.co.uk
What are Elastomers?OThermoplasticsOThermosetsONaturalOSyntheticOCan be stretched to many times
their original lengthOCan bounce back into their original
shape without permanent deformation
OLow degree of crosslinking
ElastomersOUses: examination gloves, rubber
bands, bouncing balls, hoses, medical, etc.
ONot recyclable
www.glstpes.com
Differentiate between the 2 polymers.
www.recycledplastic.com
Learning Target Learning Target CheckpointCheckpoint
Polymer Chemistry
Polymer Synthesis
Addition Polymerization(Polyaddition)
OReactions in which monomers combine without the formation of a small molecule. O Usually involves the breaking of a double
bond.
Condensation Polymerization(Polycondensation)
OReactions in which small molecules (such as H2O, and HCl) are formed when the monomers combine.
Polymerization Video
Learning Target Learning Target CheckpointCheckpoint
O How do you differentiate between condensation polymerization and addition polymerization?