25.1 - Properties of Polymers

• A polymer is a molecular substance with a high molar mass, which can range from thousands to millions of grams, and is composed of many repeating units.

• Polymer chemistry emerged in the 1920s as a result of research into the perplexing behavior of various materials like wood, gelatin, cotton, and rubber.

• Polymers began to develop in the 1920s by studying the puzzling behaviour, which included wood, gelatine, cotton and rubber.

• The solution showed several unusual properties: high viscoity, low osmotic pressure and negligible freezing point depression when the rubber dissolved into an organic solvent with the known empirical formula C5H8.

• These findings strongly indicated the presence of solutes of very high molar mass, but chemists were not prepared for the idea that these giant molecules could exist at the time.

  • This misinterpretation lasted for several years, until Hermann Staudinger Kasu showed clearly that these so-called aggregates are.

  • Huge molecules, each containing several thousand atoms held by covalent ties.

25.2 - Synthetic Organic Polymers

• The number of potential isomers is severely limited by monomers, which are simple repeating units.

• Polyethylene is an example of a homopolymer, which is a polymer composed of only one monomer type.

  • Because styrene and butadiene are separate monomers, SBR is classified as a copolymer, which is a polymer made up of two or more monomers.

• The single polyethylene chains combine well and therefore reflect the crystalline properties of the substance.

• Polyethylene is used primarily in films and packaging for frozen foods and other packaging of product.

  • Tyvek is used for home isolation as a specially treated kind of polyethylene

25.3 - Proteins

• Proteins are polymers of amino acids that are involved in practically every biological process.

• Amino acids are the basic structural units of proteins.

  • A substance with at least one amino group (NH2) and at least one carboxyl group are known as an amino acid.

• The amino acid sequence is written in a Polypeptide chain from left to right, from the amino terminal residue to the carboxyl terminal residue.

  • Consider a glycine and alanine formed dipeptide. Different dipeptides can be generated with 20 different amino acids to choose from, 202 or 400.

• The amount of chemically possible structures is even 2050 or 1065 for a very small protein, such as insulin, containing only 50 amino acid residues!

  • This is an incredibly large number, given the total number of atoms in o.

25.4 - Nucleic Acids

• Nucleic acids are polymers with a high molar mass that are required for protein production.

• The two types of nucleic acid are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

• Nucleotides are made up of three groups: a base, deoxyribose, and a phosphate group

• The key to DNA's dual-helical structure is the formation in both strands of molecules of a hydrogen bond between bases.

• While hydrogen bands can build up between any two bases called base pairs, the best connections between adenine and thymine are found between cytosine and guanine, and Watson and Crick have found.

• In the 1940s Erwin Cargaff tested and observed certain regularities of DNA molecules obtained from different sources.

• The rules of Chargaff describe these patterns as his findings are now known:

  • 1. Adenine (purine) is the same as Thymine (pyrimidine); i.e., A = T or A/T = 1. 1.

  • 2. Cytosine (pyrimidine) is equal to guanine (purine); in other words, C = G, or C/G = 1.

  • 3. The total number of bases of purine equals the total number of bases of pyrimidine, i.e. A + G = C + T.