Introduction to Polymers

Polymers

• Polymers are materials made of repeating smaller units called monomers.
• Many biological molecules are polymers.
• Polymers are classified as thermosetting or thermosoftening.
• Thermosetting polymers are permanently hardened by heat.
• Thermosetting polymers cannot be resoftened once cured.
• Thermosoftening polymers can change shape when heated.

Polymer Structures

• Linear polymers have long, straight chains of atoms.
• Branched polymers have branches attached to their chains.
• Crosslinked polymers have chains that are linked together to form a 3D network.
• Networked polymers have heavily cross-linked chains creating a complex 3D network.

Types of Polymers

• Polyethylene (PE): A thermoplastic used in many consumer products.
• Polypropylene (PP): A thermoplastic widely used in packaging and household goods.
• Polyethylene terephthalate (PET): A thermoplastic widely used in beverage bottles and clothing.
• Polybutadiene (PBD): A synthetic rubber used in tires and cables
• Polyisobutylene (PIB): A synthetic rubber with excellent toughness and flexibility.
• Polypropylene glycidyl ether (PGE): A flexible adhesive polymer used for paints, adhesives, plastics.
• Polyethylene-co-vinyl acetate (PE-VA): A thermoplastic with excellent flexibility and impact resistance, used in packaging.

Polymer Properties

• Heat Capacity: The ability of a polymer to insulate against heat flow.
• Thermal Expansion: How much a polymer expands or contracts when heated.
• Crystallinity: The degree to which polymer chains are arranged in a regular structure.
• Permeability: The tendency of a polymer to allow passage of other materials.
• Elastic Modulus: A measure of a polymer's resistance to deformation when stressed.
• Tensile Strength: The force required to break a polymer.
• Resilience: The ability of a polymer to resist abrasion and wear.
• Refractive Index: The extent to which the polymer affects light as it passes through it.
• Unreactivity: How resistant a polymer is to chemicals

Carbohydrates

• Carbohydrates are also known as saccharides.
• Carbohydrates are a major source of energy for the body.
• Their general formula is (CH₂O)n.
• Monosaccharides are the simplest sugars.
• Disaccharides are composed of two monosaccharides.
• Polysaccharides are composed of many monosaccharides, including starch, glycogen, and cellulose.

Proteins

• Proteins are polymers of amino acids.
• The fundamental elements of protein include H, C, O, and N.
• Proteins have four levels of structure: primary, secondary, tertiary, and quaternary.
• Primary Structure is the amino acid sequence.
• Secondary Structure are patterns of local folding.
• Tertiary structure is the three-dimensional arrangement of the entire polypeptide chain.
• Quarternary structure describes how different polypeptides associate with each other.

Lipids

• Lipids are a chief source of stored energy in cells.
• Lipids consists of nearly 3.5% of the whole cell contents.
• Lipids are insoluble in water but soluble in organic solvents.
• Lipids are composed primarily of C, H, and O.
• Common lipids include fatty acids, triglycerides, steroids, and waxes.

Nucleic Acids

• Nucleic acids are the genetic material of cells.
• Composed of repeating monomeric nucleic acids.
• Each nucleotide consists of a 5-carbon pentose sugar, a phosphate group, and a nitrogenous base.

Organic Chemistry

• Organic compounds are compounds that contain carbon.
• Many elements (particularly hydrogen, oxygen, and nitrogen) are linked by covalent bonds to carbon atoms.