Polymers Test - 3

• Neoprene is not a condensation polymer. It is an addition polymer.
• Neoprene is made from monomer chloroprene (2-chlorobuta-1,3-diene). 
• Dacron, Melamine and Glyptal are condensation polymers.
• Dacron ( also known as terylene) is a polyester made by condensation polymerisation of ethylene glycol and dimethyl terephthalate.
• Glyptal is a copolymer of ethylene glycol and phthalic acid.
• Melamine ( or formaldehyde melamine polymer) is obtained from condensation polymerisation of melamine with formaldehyde.

1. ELASTOMERS - The polymer chains are held together by the weakest intermoleculer faces. These weak binding forces permit the polymer to be stretched. 
   
2. FIBERS - Fibers have strong intermoleculer forces like hydrogen bonding. These strong forces also lead to close packing of chains and thus impact crystalline nature. 
3. THERMOPLASTICS - They posses intermoleculer forces of attraction intermediate between elastomers and fibers. 
4. THEMOSETTING - They are cross linked & heavily launched. 

• Natural polymers abound Proteins, starches, carbohydrates, even DNA are natural polymers.

• A hamburger consists mostly of polymers. The cardboard container the hamburger came in and the napkin used to wipe up any ketchup spills are also made of polymers.
• Understanding natural polymers' structure, characteristics and uses can help people make environmentally conscious and informed choices. 

• Addition polymerization takes place when the monomer molecule contains double carbon bonds, as in alkenes, or triple carbon bonds, as in alkynes.

• Cotton is defined as a plant or the soft cloud-like substance that comes from shrubby plants and is used to make thread or cloth.
  
• An example of cotton is the stuffing inside a teddy bear.
  

Decron is a condensation polymer. It is formed by the condensation of ethylene glycol and terephthalic acid. 

• Perhaps the "semi-synthetic" polymers that was stated in the question refers to this kind of polymers. For example, cellulose acetate is a thermoplastic polymer that is produced from cellulose, a natural polymer, rather than through polymerization reaction of a monomer.
• Actually, there is no polymerization reaction in the production process of polymer products like cellulose nitrate and other chemical derivatives of cellulose.

So, they can be considered as semi-synthetic polymers.

• Polyacrylonitrile is an example of addition polymer.
• The addition polymerisation of acrylonitrile in presence of a peroxide catalyst leads to the formation of polyacrylonitrile.

Synthetic Polymers: Polymers are large molecules composed of repeated chemical units. The smallest repeating unit is called a mer. The term polymer is derived from the Greek words poly and mers meaning "many parts."

• The reaction between phthalic acid and glycerol initially results into linear or branched polymer but, due to trifunctionality of glycerol, ultimately cross-linking takes place between the molecules.