Organic Chemistry - Polymers

Explore polymers in everyday life, from natural rubber and carbohydrates to plastics and contact lens materials, and learn to make, classify, and use polymers.

Learn how monomers form polymers through repeating units and high molecular weight macromolecules, formed by linking many monomer units, and distinguish polymers from non-polymers like chlorophyll.

Explore polymer functionality as the number of reacting sites on a monomer, illustrated with mono-functional examples, then examine repeating units and the roles of A and B in polymers.

Explore the six criteria for classifying polymers, including availability, polymerization process, molecular interactions, structure, monomers, and biodegradability, in this introductory lecture.

Classify polymers by availability into natural, semi-synthetic, and synthetic, noting natural polymers from nature and their biodegradability, semi-synthetic polymers derived by chemical treatment, and synthetic polymers formed by polymerization.

Classify polymers by structure into linear, branched, and crosslinked networks. Highlight crosslinked polymers forming a 3D covalent network, while linear polymers pack densely and branched forms have lower density.

This lecture classifies polymers by mode of polymerization into addition (chain-growth) polymers, condensation (step-growth) polymers, and ring-opening polymerization, with examples like polyethylene, PVC, and nylon 6.

Classify polymers by monomer type, distinguishing homopolymers, which have a single repeating unit, from copolymers, which contain two or more monomer types with random sequencing.

The lecture classifies polymers by molecular forces into elastomers, fibers, thermoplastics, thermosetting polymers, and oriented polymers, linking elasticity, strength, crosslinking, and recyclability to the underlying interactions.

Explore the classification of polymers by biodegradability into two types: biodegradable polymers degraded by microbes and enzymes, and non-biodegradable polymers, typically synthetic, with environmental implications.

Explore addition polymerization, where monomers join without elimination to form long polymers, through head-to-head, head-to-tail, and random growth, via free radical and ionization addition polymerization mechanisms.

Explore polyvinyl chloride (PVC) as a major polymer and its addition polymer formation via a free radical mechanism with benzoyl peroxide initiator, highlighting insulating uses in pipes and electrical applications.

Explore free radical addition polymerization, identifying how free radicals are generated by a radical generator, initiating the process and driving propagation with examples like hydrogen peroxide and sunlight.

Explore the three steps of free radical addition polymerization—initiation, propagation, and termination—showing how free radicals are generated by light or a free radical generator to drive polymer formation from monomers.

Explore ionic addition polymerization, distinguishing cationic and anionic mechanisms, intermediates, initiators, and how electron-donating or electron-withdrawing groups stabilize charged species.

Initiate the anionic addition polymerization by forming a carbanion from a strong base, then propagate through successive monomer additions, and finally terminate the growing chain.

Explore the mechanism of cationic addition polymerization, from initiation forming a carbocation to propagation with repeated monomer addition, and termination by proton removal, highlighting stabilization by electron-donating groups.

Learn how polyethylene, or polythene, forms from the ethylene monomer under specific conditions to yield low-density and high-density polymers with branching and density differences.

Explore condensation polymerization, where two functional group monomers join with removal of a small molecule, such as water or ammonia, to form polymers like nylon through self-condensation and cross-condensation.

Explore polyester formation by condensation polymerization of benzene-1,4-dicarboxylic acid and ethylene glycol, yielding ester linkages and Dacron's crease and grease resistance in clothing.

Explore nylon-6,6, a polyamide formed from two monomers, via condensation polymerization at high temperature to remove water. Learn its heat and water resistance and its use in clothes and swimwear.

Explore nylon-6,10 synthesis as a polyamide from two monomers via condensation polymerization, yielding amide linkages and offering heat and water resistance for plastic, raincoats, and fishing nets.

Learn how polyamides form nylon-6 via ring-opening polymerization of caprolactam, yielding water-resistant fibers used in raincoats, nets, and other nylon products.

Explore the phenol–formaldehyde polymer Bakelite formed by condensation of phenol with formaldehyde under basic conditions, yielding benzyl alcohol intermediates and a crosslinked polymer with practical uses.

Explore the melamine formaldehyde polymer, a heat- and moisture-resistant polymer formed by condensation polymerization of melamine and formaldehyde, used in decorative materials and microwave crockery.

This lecture explains polyesters as alkyd resins like glyptal, showing how ethylene glycol and a benzene diacid form ester linkages by condensation, yielding varnish-relevant repeating units.

Explore copolymerization, defining copolymers formed from two or more monomers, and compare addition and condensation polymerization. Examine styrene-butadiene rubber as an example and note distinct physical properties from homopolymers.

Classifies copolymers by monomer arrangement into four types, including random, block, and graft copolymers; uses A and B monomers and gamma-ray grafting examples.

Explore rubber as a flexible elastomer polymer, its conjugated monomers like 1,3-butadiene, and classify rubber into natural and synthetic origins, including preparation and processing.

Discover how natural rubber comes from rubber tree latex, containing about 35 percent solids, processed to crude rubber. Isoprene units polymerize by 1,4 addition to polyisoprene.

Explore the vulcanization of natural rubber by crosslinking with sulfur, accelerated by zinc oxide, to improve elasticity, solvent and oxidation resistance, and durability.

Explore synthetic rubber through neoprene, a homo polymer derived from 1,3-butadiene formed by addition polymerization via free-radical or Ziegler-Natta catalysis, and highlight its uses like gaskets and superior strength.

Explore Buna-N, a nitrile rubber from butadiene and another monomer via addition polymerization in the presence of peroxide, highlighting oil resistance and uses in gloves and aeronautics.

Explore buna-s, a styrene–butadiene copolymer formed by addition polymerization. Learn how sodium catalysis yields a general purpose synthetic rubber used in tires and as an elastomer.

Explore factors shaping polymerization degree, including temperature, pressure, and monomer availability, and learn to calculate number-average and weight-average molecular masses with a practical example.

Explain biodegradable polymers and enzyme-driven degradation by microorganisms to reduce pollution. Highlight PHBV, a beta hydroxybutyrate and beta hydroxyvalerate copolymer, formed by condensation and used in orthopedic devices and drug delivery.

Explore coordination polymerization using a Ziegler-Natta catalyst, where electron donation from unsaturated monomers forms a coordinated intermediate, yielding isotactic, syndiotactic, or atactic polymer arrangements.

Discover the polydispersity index (PDI) as the Mw/Mn ratio. Learn why natural polymers have PDI equal to one, while synthetic polymers exceed one, and how distribution width influences material properties.

Understand how plasticizers soften and make plastics flexible by lowering softening points. Observe that they reduce melting points and can evaporate under sunlight, leaving hard, brittle materials.