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 ↓


Biodegradable Polymer


In the world of chemistry, polymers play an important role. They are large molecules made up of smaller repeating units called monomers. Polymers are found everywhere in our daily lives, from the plastics in our water bottles to the fibers in our clothing. But a significant concern with many synthetic polymers is their environmental impact. Traditional polymers such as polyethylene and polystyrene are not biodegradable and can persist in the environment for hundreds of years. This is where biodegradable polymers come into play.

What are biodegradable polymers?

Biodegradable polymers are a type of polymer that can be broken down into water, carbon dioxide, and biomass by natural processes. This breakdown is mainly carried out by microorganisms such as bacteria and fungi. The biodegradable nature of these polymers makes them a promising solution for reducing environmental pollution, especially in the management of plastic waste.

Visual example of a biodegradable polymer structure

Monomer A Monomer B Monomer C Monomer A

In the image above, different monomers (A, B and C) link together to form polymer chains. These biodegradable polymers can break down into their individual components when exposed to natural conditions.

Chemistry of biodegradable polymers

The chemistry of biodegradable polymers involves the creation of polymers through natural or synthetic pathways that can be decomposed efficiently. These polymers can be broken down through enzymatic or hydrolytic processes.

A common type of biodegradable polymer is polylactic acid (PLA), which is synthesized from the monomer lactic acid. It is a naturally occurring compound that can be produced by fermentation of corn starch or other carbohydrates.

        Polymerization of PLA:
    n(C₃H₆O₃) → (C₃H₄O₂)ₙ + n(H₂O)

Here, the lactic acid units (C₃H₆O₃) polymerize to form polylactic acid (PLA), with water being a byproduct of the reaction.

Types of biodegradable polymers

There are several types of biodegradable polymers, classified based on the method of decomposition. These are:

  • Naturally occurring biodegradable polymers: These include proteins, polysaccharides such as starch and cellulose, and others that are naturally produced by living organisms.
  • Synthetic biodegradable polymers: These are chemically synthesized substances designed to break down easily. Examples include polyglycolide, polylactic acid, and polycaprolactone.

Process of biodegradation

Biodegradation is a complex process involving many steps and factors. It generally involves the following steps:

1. Hydrolysis

The first step is the breaking of the polymer chain by hydrolysis, where water molecules break ester or amide bonds within the polymer. This step can be visualized as follows:

        Hydrolysis of ester bonds:
    RCOOR' + H₂O → RCOOH + R'OH

Here, the ester bond within the polymer is broken to form carboxylic acid (RCOOH) and alcohol (R'OH).

2. Enzymatic degradation

Following hydrolysis, enzymes produced by microorganisms break down polymer fragments into smaller, water-soluble molecules. These enzymes work specifically on certain types of bonds.

3. Assimilation

Microorganisms assimilate small molecules as a source of energy and carbon. This is a crucial step, where the fragmented molecules are incorporated into microbial biomass.

4. Mineralization

In the final step the polymer fragments are completely oxidized under anaerobic conditions to inorganic substances such as carbon dioxide, water, and methane.

Benefits of biodegradable polymers

Biodegradable polymers offer several important benefits, including:

  • Reduced environmental impact: By decomposing naturally, these polymers help reduce persistent plastic pollution.
  • Use of renewable resources: Biodegradable polymers often come from renewable resources such as corn starch, which helps conserve fossil fuels.
  • Compostability: Many biodegradable polymers can be composted with organic waste, reducing overall waste disposal demands.

Applications of biodegradable polymers

Due to their eco-friendly properties, biodegradable polymers have found applications in various fields, such as:

Medical field

Biodegradable polymers are used in the manufacture of sutures, orthopedic implants, and drug delivery systems. For example, polylactic acid (PLA) and polyglycolic acid (PGA) are commonly used in medical applications.

Packaging

These are used in the production of packaging materials, significantly reducing plastic waste. PLA is a popular choice for making biodegradable packaging films.

Agriculture

Biodegradable polymers can be used in the production of mulch films and controlled-release fertilizers. These films decompose after a certain period of time, eliminating the need to remove them.

Challenges and future directions

Despite their benefits, there are some challenges to the widespread adoption of biodegradable polymers:

  • Cost: Biodegradable polymers typically have higher production costs than conventional plastics.
  • Infrastructure: Lack of proper composting infrastructure can hamper the decomposition process.
  • Performance: The mechanical properties of biodegradable polymers may be inferior to those of conventional plastics, limiting their applications.

Future research aims to overcome these challenges by developing cost-effective production methods and enhancing the mechanical properties of these polymers to make their performance comparable to or better than their non-biodegradable counterparts.


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Biodegradable Polymer

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