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


Polymer chemistry is a fascinating and important field within organic chemistry that focuses on the study of polymers. Polymers are large molecules composed of repeating subunits, known as monomers. Understanding polymers is important because they are used in countless everyday materials and have a wide variety of applications, from plastic bottles to clothing and medical devices. In this comprehensive exploration, we will dive deep into the fundamental concepts of polymer chemistry, including types of polymers, methods of polymerization, and practical examples of polymer applications.

What are polymers?

Polymers are macromolecules composed of repeating structural units, usually linked by covalent chemical bonds. The repeating units, or monomers, join together through various polymerization processes to form long chains or complex three-dimensional structures.

Examples of common polymers include:

  • Polyethylene (PE) - Used in plastic bags and bottles.
  • Polyvinyl chloride (PVC) - used in pipe and cable insulation.
  • Polystyrene (PS) – used in foam cups and packaging.
  • Nylon - used in clothing and ropes.
  • Polytetrafluoroethylene (PTFE) – Better known as Teflon, it is used in non-stick coatings.

Structure and characteristics of polymers

The structure of a polymer can significantly affect its physical and chemical properties. Some of the key structural factors include chain length, degree of polymerization, and branching. Let's explore these concepts:

Chain length: The length of a polymer chain, commonly called molecular weight, affects properties such as strength, flexibility, and melting point. Longer chains generally lead to stronger materials.

Degree of polymerization: This is the number of repeating units in a polymer molecule. Higher degrees of polymerization often lead to higher molecular weights and stronger materials.

Branching: Polymers can exhibit different types of branching, such as linear, branched or cross-linked. Each type of branching changes the properties of the polymer. Linear polymers are flexible, while cross-linked polymers, such as in rubber, are rigid and heat resistant.

Polymer nomenclature

Polymer naming can be complicated because of the variety of possible structures. Typically, polymers are named based on their monomers. Consider the following examples:


// Polyethylene is named for its repeating unit: ethylene (C2H4). 
// Polyvinyl chloride is named for vinyl chloride monomer (C2H3Cl). 
// Polystyrene is derived from the monomer styrene (C8H8).

Types of polymerization

Polymerization is the process of converting monomers into polymers. There are two main types of polymerization: addition polymerization and condensation polymerization.

Addition polymerization

Addition polymerization involves repeatedly adding monomers containing unsaturated bonds (such as double bonds) to form a polymer. A common example is the polymerization of ethylene to form polyethylene:


n C2H4 → (C2H4)n

This process may be radical, cationic, or anionic, depending on the type of reactive intermediate involved.

Condensation polymerization

Condensation polymerization involves a reaction between two different monomers, usually eliminating a small molecule such as water or methanol as a byproduct. A classic example of this is the formation of nylon from hexamethylenediamine and adipic acid:


n H2N(CH2)6NH2 + n HOOC(CH2)4COOH → (-NH(CH2)6NHCO(CH2)4CO-)n + (2n - 1) H2O

In this process, monomers containing two functional groups typically react, resulting in strong polymers with higher molecular weights.

Copolymerization

Copolymers are polymers made from two or more different types of monomers. This process allows polymer properties to be fine-tuned by combining the characteristics of different units. Examples include:


// Styrene-butadiene rubber (SBR) is a copolymer of styrene and butadiene, used in tire production. 
// Acrylonitrile-butadiene-styrene (ABS) is a copolymer made from acrylonitrile, butadiene, and styrene, commonly used in 3D printing.

Effect on polymer properties

Many factors affect the properties of polymers, including:

  • Temperature: Heat can cause changes in polymer flexibility, strength, and crystalline structures. Polymers have a glass transition temperature (Tg) below which the material is glass-like and rigid.
  • Plasticizers: These are small molecules that can be added to polymers to increase flexibility.
  • Crystallinity: The degree of orderliness of the polymer chains. Highly crystalline polymers are stronger and more durable.

Polymer applications

Polymers are ubiquitous in everyday life because of their versatile properties. Here, we'll explore some applications:

Plastic

Plastics are perhaps the most widely recognized application of polymers. They can be molded into myriad shapes and forms, making them invaluable in packaging, construction, automotive parts, and electronics.

Examples include:

  • Polyethylene: It is used in making bags, containers and bottles.
  • Polypropylene: Used for food containers and automotive parts.

Rubber

Natural and synthetic rubbers, such as those used in tires, are made from elastomeric polymers. These materials can stretch extensively and regain their shape, making them essential in automotive and industrial applications.

Example:

  • Natural rubber: Latex derived from rubber trees, known for its elasticity and resiliency.
  • Synthetic rubber: Such as polybutadiene and styrene-butadiene rubber, used in tire manufacturing.

Fibers

Polymeric fibers are important in the textile industry, providing materials for apparel, upholstery, and nonwoven fabrics.

Examples include:

  • Nylon: It is widely used in clothing and carpets due to its strength and flexibility.
  • Polyethylene terephthalate (PET): Used to make polyester fabric.

Adhesives

Polymeric adhesives such as epoxies and polyurethanes provide strong bonding capabilities to a variety of substrates, making them essential in construction and manufacturing.

Environmental impact and recycling

The widespread use of polymers, especially plastics, has raised environmental concerns. Plastics are durable and resistant to biodegradation, leading to waste accumulation in landfills and oceans.

Efforts to tackle this problem include recycling and developing biodegradable polymers. Recycling involves transforming waste materials into new products, thereby reducing raw material consumption and waste.

Biodegradable polymer

Biodegradable polymers are designed to decompose naturally into non-toxic substances, reducing environmental impact. Polylactic acid (PLA) and polyhydroxyalkanoates (PHA) are examples of biodegradable polymers used in packaging and medical applications.

Conclusion

Polymer chemistry, an essential branch of organic chemistry, plays a vital role in modern society. The versatility of polymers underlies applications in various industries, making them an integral part of our daily lives. From their structural properties to synthesis methods, polymers offer endless possibilities for innovation.

As environmental awareness grows, the development of sustainable polymers and recycling strategies will become increasingly important. Understanding and harnessing the potential of polymers and minimizing their environmental impact remains a valuable pursuit in the field of chemistry.


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Polymer chemistry

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