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?