Polymer Chemistry: Classification of Polymers. The most common way of classifying polymers is to separate them into three groups – thermoplastics, thermosets, and elastomers. The thermoplastics can be divided into two types – those that are crystalline and those that are amorphous.

The lower the molecular weight, lower the transition temperature, viscosity, and the mechanical properties. Due to increased entanglement of chains with increased molecular weight, the polymer gets higher viscosity in molten state, which makes the processing of polymer difficult.

Polymers consist of very long molecules that contain chains of carbon. They too are held together by very strong covalent bonds. There are greater intermolecular forces between the long chains compared with smaller simple molecules. This means that polymers have a higher melting point than many other organic molecules.

: a chemical compound or mixture of compounds formed by polymerization and consisting essentially of repeating structural units. Other Words from polymer Example Sentences Learn More about polymer.

Proteins are the macromolecules which are made from the amino acids when joined together by peptide bonds. Amino acids are polymers which are used to build tissues and other components of living organisms. Thus, they are called biological polymers.

Proteins – polymers are known as polypeptides; monomers are amino acids. Nucleic Acids – polymers are DNA and RNA; monomers are nucleotides, which are in turn consist of a nitrogenous base, pentose sugar, and phosphate group.

Proteins are polymers of amino acids. Each amino acid contains a central carbon, a hydrogen, a carboxyl group, an amino group, and a variable R group.

Rubber is a name given to a lot of different polymers that are all elastomers. They were “inspired” by natural rubber. Rubber actually got its name when people in Britain figured out that it could be used to erase or “rub out” mistakes made with a pencil.

Thiokol is polymer of CH2C1CH2C1 and sodium polysulphide Na-S-S-Na and thus, not polydiene rubber.

Natural rubber is a polymer of isoprene (also known as 2-methylbuta-1,3-diene) with the chemical formula (C5H8)n. To put it more simply, it’s made of many thousands of basic C5H8 units (the monomer of isoprene) loosely joined to make long, tangled chains.

Natural rubber is made by extracting a liquid sap, called latex, from certain types of tree. These trees are native to South America but are today commonly found in Southeast Asia. Latex is gathered from the trees by making a cut in the bark and collecting the runny sap in cups. This process is called tapping.

Rubber is a natural product produced by plants and is present in many of the goods used in our daily lives. It still plays an important role, and that is why we need to search for new rubber sources. Nowadays, 99% of the natural rubber we use is extracted from a tree called Hevea brasiliensis.

Natural rubber has certain unique properties such as follows:

• Natural rubber combines high strength (tensile and tear) with outstanding resistance to fatigue.
• It has excellent green strength and tack which means that it has the ability to stick to itself and to other materials which makes it easier to fabricate.

The following are the physical properties of rubber:

• Specific gravity.
• Abrasion resistance.
• Tear resistance.
• Compression set.
• Resilience.
• Elongation.
• Tensile modulus.
• Tensile strength.

Rubber is water repellent and resistant to alkalies and weak acids. Rubber’s elasticity, toughness, impermeability, adhesiveness, and electrical resistance make it useful as an adhesive, a coating composition, a fiber, a molding compound, and an electrical insulator.