Undergraduate
  1. General chemistry  1.1. Introduction to Chemistry  1.2. Atomic Structure  1.2.1. Subatomic particles  1.2.2. Atomic Model  1.2.3. Quantum numbers  1.2.4. Electron Configuration  1.2.5. Periodic trends  1.2.6. Isotopes and their applications  1.3. Chemical bond  1.3.1. Ionic bond  1.3.2. Covalent bonds  1.3.3. Metal Bond  1.3.4. Hybridization  1.3.5. Molecular geometry and VSEPR theory  1.3.6. Bond polarity and dipole moment  1.4. Stoichiometry  1.4.1. Mole concept  1.4.2. Empirical and molecular formula  1.4.3. Limiting reactant and excess reactant  1.4.4. Percent Yield and Purity  1.4.5. Dilution calculation  1.5. States of matter  1.5.1. Gas Laws  1.5.2. Matter and Intermolecular Forces  1.5.3. Solid and Crystal Structures  1.5.4. Phase diagram  1.5.5. Plasma and supercritical fluid  1.6. Chemical reactions  1.6.1. Types of Chemical Reactions  1.6.2. Balancing Chemical Equations  1.6.3. Thermochemical reactions  1.6.4. Reaction energy profiles  1.7. Solutions and Mixtures  1.7.1. Concentration units  1.7.2. Syndrome properties  1.7.3. Solubility and Solubility Rules  1.7.4. Henry's Law and Raoult's Law  1.7.5. Partition coefficient  1.8. Chemical equilibrium  1.8.1. Law of mass action  1.8.2. Le Chatelier's principle  1.8.3. Reaction quotient  1.8.4. To use this online calculator for Equilibrium Constant, enter Equilibrium Constant (Eq.) and hit the calculate button. Here is how the Equilibrium Constant calculation can be explained with given input values -> 0.05 = 0.05/0.  1.8.5. Acid-base balance  1.9. Acids and bases  1.9.1. Arrhenius, Brønsted–Lowry, and Lewis definitions  1.9.2. pH and pOH  1.9.3. Acid-base titration  1.9.4. Buffer Solution  1.9.5. Acid-base indicator  1.9.6. Polyprotic Acids and Bases  1.10. Electrochemistry  1.10.1. redox reactions  1.10.2. Galvanic and Electrolytic Cells  1.10.3. Nernst equation  1.10.4. Electrolysis  1.10.5. Faraday's laws of electrolysis  1.11. Thermodynamics  1.11.1. Laws of Thermodynamics  1.11.2. Enthalpy, entropy and Gibbs free energy  1.11.3. Spontaneity of reactions  1.11.4. Thermodynamic cycles (Hess's law, Carnot cycle)  1.12. Kinetics  1.12.1. Rate law and reaction order  1.12.2. Activation Energy and Catalyst  1.12.3. Collision theory  1.12.4. Reaction mechanism  1.12.5. Transition state theory
  2. Organic chemistry  2.1. Structure and relationships  2.1.1. Hybridisation in Carbon Compounds  2.1.2. Resonance and aromatization  2.1.3. Molecular orbitals  2.1.4. Inductive and mesomeric effects  2.2. Hydrocarbons  2.2.1. Hydrocarbons  2.2.2. Alkene  2.2.3. Alkynes  2.2.4. Aromatic compounds  2.2.5. Cycloalkanes and Conformation  2.3. Functional Group  2.3.1. Alcohols and phenols  2.3.2. Ethers and epoxides  2.3.3. Aldehyde and ketone  2.3.4. Carboxylic acids and derivatives  2.3.5. Amin  2.3.6. Esters and amides  2.3.7. Thiols and sulfides  2.4. Stereoscopic  2.4.1. Isomerism in Stereochemistry  2.4.2. Chirality and optical activity  2.4.3. Structural analysis  2.4.4. Diastereomers and Enantiomers  2.5.1. Substitution reactions  2.5.2. Elimination reactions  2.5.3. Addition reactions  2.5.4. Radical reactions  2.5.5. Rearrangement reactions  2.5.6. Pericyclic Reactions  2.6. Spectroscopy and structural analysis  2.6.1. Infrared Spectroscopy  2.6.2. Nuclear magnetic resonance spectroscopy  2.6.3. Mass Spectrometry  2.6.4. UV-visible spectroscopy  2.6.5. X-ray crystallography  2.7. Polymer chemistry  2.7.1. Addition and Condensation Polymers  2.7.2. Polymerization mechanism  2.7.3. Biodegradable Polymer  2.7.4. Conducting and smart polymers
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Ligands and coordination compounds  3.1.2. Crystal field theory  3.1.3. Molecular Orbital Theory in Coordination Compounds  3.1.4. Jahn–Taylor distortion  3.2. Main Group Chemistry  3.2.1. Alkali and alkaline earth metals  3.2.2. Halogens and Noble Gases  3.2.3. Transition metals and their complexes  3.2.4. Lanthanides and Actinides  3.3. Solid state chemistry  3.3.1. Crystal lattices and unit cells  3.3.2. Defects in solids  3.3.3. Electrical and magnetic properties  3.3.4. Superconductivity  3.4. Bio-inorganic chemistry  3.4.1. Metal ions in biology  3.4.2. Enzymatic reactions with metals  3.4.3. Metal poisoning and detoxification  3.4.4. Metalloproteins and Metalloenzymes
  4. Physical chemistry  4.1. Quantum Chemistry  4.1.1. Wave–particle duality  4.1.2. Schrödinger Equation  4.1.3. Quantum Numbers and Orbitals  4.1.4. Atomic and molecular spectroscopy  4.2. Statistical mechanics  4.2.1. Maxwell–Boltzmann distribution  4.2.2. Partitioning functions  4.2.3. Bose–Einstein and Fermi–Dirac statistics  4.3. Chemical thermodynamics  4.3.1. Gibbs Free Energy  4.3.2. Phase transition  4.3.3. Thermodynamic efficiency  4.4. Surface chemistry  4.4.1. Absorption and Catalysis  4.4.2. Colloids and Emulsions
  5. Analytical Chemistry  5.1. Classical methods  5.1.1. Gravimetric Analysis  5.1.2. titrimeter  5.2. Instrumental methods  5.2.1. Chromatography  5.2.2. Spectroscopy  5.2.3. Electroanalytical methods  5.2.4. X-ray diffraction
  6. Industrial Chemistry  6.1. Petrochemistry  6.2. Chemical engineering principles  6.3. Green Chemistry  6.4. Pharmaceuticals and Drug Synthesis
  7. Biochemistry  7.1. Carbohydrates  7.2. Proteins and enzymes  7.3. Lipids and membranes  7.4. Nucleic acids  7.5. Metabolism and Bioenergetics  7.6. Enzyme kinetics and mechanism

Undergraduate → Organic chemistry → Polymer chemistry ↓


Addition and Condensation Polymers


In the fascinating world of organic chemistry, polymers represent an important class of materials characterized by repeated structural units called monomers. Broadly speaking, two main types of polymerization processes are used to make polymers: addition polymerization and condensation polymerization. Each of these processes leads to the formation of polymers with specific properties.

Additive Polymer

Addition polymers are produced by the addition polymerization process, where monomers are joined together without losing any of the smaller molecules. Typically, these monomers are unsaturated molecules such as alkenes or other compounds with double bonds.

Mechanism of Addition Polymerization

The mechanism of addition polymerization can be discussed as occurring in three main steps:

1. Initiation

The initial step usually involves the formation of specific reactive intermediates of free-radical, cationic or anionic species. Initiators such as peroxides are often used:

ROOR' → 2R• (radical initiator splitting)

This reactive species attacks the π-bond of a monomer to create an active site for chain propagation.

R• + CH 2 =CH 2 → R-CH 2 -CH 2 •

2. Diffusion

During the propagation phase, the reactive species continue to add additional monomers in a chain reaction process:

R-CH 2 -CH 2 • + CH 2 =CH 2 → R-CH 2 -CH 2 -CH 2 -CH 2 •

This step is repeated many times, forming a long polymer chain.

3. Termination

The chain reaction stops during termination, which can occur by a variety of pathways, often involving combination or disproportionation:

R-CH 2 -CH 2 • + R'• → R-CH 2 -CH 2 -R'

Common Examples of Additive Polymers

Some well-known addition polymers include the following:

  • Polyethylene: Made from the polymerization of ethylene, this is one of the most common plastics.
    • n(CH 2 =CH 2 ) → -[CH 2 -CH 2 ]- n
  • Polypropylene: Produced by the polymerization of propylene, it is widely used in the packaging and textile industries.
    • n(CH 2 =CHCH 3 ) → -[CH 2 -CH(CH 3 )]- n
  • Polystyrene: Made from styrene monomers, used to make packaging materials and disposable containers.
    • n(CH 2 =CHPhenyl) → -[CH 2 -CH(Phenyl)]- n

Visual example of polyethylene construction

Initiation Publicity Closure

Condensation Polymer

Condensation polymers are formed through a reaction in which monomers are bonded together through the loss of smaller molecules, such as water or methanol. These polymers often involve the interaction of functional groups such as alcohols, carboxylic acids, or amines.

Mechanism of condensation polymerization

This process can often be represented by the following reactions:

HO-R-OH + HOOC-R'-COOH → HO-R-OOC-R'-COOH + H 2 O

Here, the hydroxyl and carboxylic acid groups react to form ester bonds and release water, forming polyester in repeated cycles.

Common Examples of Condensation Polymers

Examples of widely used condensation polymers are:

  • Nylon-6,6: Made from hexamethylenediamine and adipic acid, used in fibers and textiles.
    • HOOC-(CH 2 ) 4 -COOH + H 2 N-(CH 2 ) 6 -NH 2 → -[OC-(CH 2 ) 4 -CO-NH-(CH 2 ) 6 -NH]- n + nH 2 O
  • Polyester: Produced by the reaction between a dicarboxylic acid and a diol.
    • HO-(CH 2 ) 2 -OH + HOOC-C 6 H 4 -COOH → -[O-(CH 2 ) 2 -OOC-C 6 H 4 -CO]- n + nH 2 O

Visual example of polyester manufacturing

monomer reaction HO-(CH 2 ) 2 -OH HOOC-C 6 H 4 -COOH Polymer Linkages -[O-(CH 2 ) 2 -OOC-C 6 H 4 -CO]-

Main Differences Between Addition and Condensation Polymers

Although both types of polymers are widely used, they serve different purposes due to their unique properties. Some of the differences are as follows:

  • Monomers: Addition polymers usually require monomers with double bonds, while condensation polymers are formed from monomers with two functional end groups.
  • Byproducts: Addition polymerization results in no byproducts, while condensation polymerization often results in the release of smaller molecules such as water or HCl.
  • Process: Addition polymerization involves free-radical, ionic, or coordination processes, while condensation polymerization usually involves step-growth.

Applications of Polymers

Both addition and condensation polymers have numerous applications:

  • Addition polymers: Used in packaging (polyethylene), manufacturing of automotive parts (polypropylene) and making insulators (polystyrene).
  • Condensation polymers: used in the textile industry (as nylon and polyester fibres), engineering plastics and architectural applications.

The scope of application is enormous, making knowledge of polymers fundamentally important in the production of everyday objects and industrial products. These polymers are valued for their versatility, durability, and flexibility to be engineered into custom materials with desired properties.


Undergraduate → 2.7.1


U
username
0%
completed in Undergraduate

← Prev (2.7)
Polymer chemistry
Next (2.7.2) →
Polymerization mechanism

Comments 



Addition and Condensation Polymers

https://www.chemistryelite.com/ug/2.7.1?ceal=en