RBSE Class 12 Chemistry Notes Chapter 15 Polymers

These comprehensive RBSE Class 12 Chemistry Notes Chapter 15 Polymers will give a brief overview of all the concepts.

RBSE Class 12 Chemistry Chapter 15 Notes Polymers

→ Polymer: The moleculs which have more than 10000 molecular mass are called macromolecules and that macromolecules are called polymers.

→ Monomer: Simple and reactive molecules from which the polymer are prepared either by addition or condensation are called monomer.

→ Polymerisation: The process by which monomers are converted into polymers is called polymerisation. 

→ Natural Polymers: Polymers found in nature, mostly in plants and animals are called natural polymers, e.g., proteins etc.

→ Semi Synthetic Polymer : Polymers which are obtained by making some modification in natural polymers by artificial means, e.g. nitro-cellulose, cellulose accetate etc.

→ Synthetic Polymer: These are man-made polymers prepared in laboratory, e.g. polyethene, teflon, nylon etc.

→ Linear Polymer: These polymers consist of long and straight chains e.g. high density polyethene, nylon, poly vinylchloride etc.

→ Branched Chain Polymers: These polymers contain linear chain having some branches e.g. low density polyether, glycogen etc.

→ Cross linked or Network Polymers: These polymers are usually formed from bifunctional and trifunctional monomers and contain strong covalent bonds, e.g. Bakelite, malamine etc.

→ Addition Polymers : The addition polymers are formed by the repeated addition of same or different monomers, e.g. Polyethene.

→ Homopolymer: Polymers whose repeating structural units are derived from only one type of monomer units are called homo-polymer. For example Polyethene, PAN, Teflon.

→ Co-polymer : Polymer whoes repeating structural units are derived from two or more types of monomer molecules, are called copolymers e.g. Buna S, Buna N, Nylon, 6,6 etc.

→ Condensation Polymer: The condensation polymers are formed by the reaction between different bifunctional or trifunctional monomer units usually with elimination of small molecules like water, alcohol etc. e.g. Nylon 6,6 and Terylene.

→ Elastomers : There are the polymers having the weakest intermolecular forces of attraction between the polymer chains. Elastomers thus posses an elastic character e.g. Buna-S, Neoprene.

→ Artificial Fibre: These are the polymers which have the strongest intermoleculer forces such as hydrogen bond or dipole-dipole interaction, e.g. Nylon 6,6 and Terylene.
 
→ Thermoplastic Polymer: The polymers whose inter-molecular forces of attraction are intermediate between elastomers and fibres. There are linear or slightly branched chain polymers capable of repeately softening on heating. e.g. polyethene, polystryrene etc.

→ Thermosetting Polymer: These polymers are cross linked branched molecules, which on heating undergo extensive cross linking in moulds and again become infusible e.g. Bakelite, Urea formaldehyde resins etc.

→ Some Important Points:

• Average molecular weight can be represented as no average molecular mass and mass average molecular mass.
• Ratio of average molecular weight mass and average number molecular mass is called polydispersity index.
• Polymerisation of diene is done by organometallic compounds. In which Ziegler Natta catalyst is main.
• State at which polymer melted are called visco fluid state.
• That temprature at which polymer melts and flow are called flow temprature.
• Natural rubber is obtained by latex of Hevea Brasiliensis Plant, and in reaction with sulphur is called vulcanisation of rubber.
• Proteins, cellulose, starch, nucleic Acids are biopolymers which are divided in the presence of particular enzyme.
• PMMA is poly methyl methaacrylate.
• PAN is polyacronitrile.
• PTFE is Polytetra fluoro ethylene and PCTFE is Poly mono chloro fluoro ethylene.
• Melamine formaldenyde is nonbreakable plastic which are used in making crockery.
• Ziegler Natta is a catalyst which is used in making Polyethene of high density.
• Thermosetting polymers can be moulded again but thermo plastics can't be moulded again.
• Poly isoprene is natural rubber but neoprene is synthetic'Rubber.
• Terylene is Glyptal Polyester but Nylon-6 and Nylon 6,6 are polyamides.