Theoretical concepts are also discussed wherever necessary. Question 12: Write the monomers used for getting the following polymers : i Polyvinyl chloride ii Teflon iii Bakelite Answer: i vinyl chloride ii tetrafluoroethylene iii phenol and formaldehyde. How can biodegradable synthetic polymers be made. They have high tensile strength due to presence of strong inter molecular hydrogen bond. We at Takshila Learning, always do best to keep our students ahead in terms of learning and preparation. Can nucleic acids, proteins and starch be considered as step growth polymers? This will help them to understand the chapter properly and also find any area for improvement. Examples of such polymers include bakelite and melmac.
Solution: a Given polymer can be obtained condensation polymerization of ethylene glycol and phthalic acid with the elimination of water molecule. They have low densities, low tensile strength as well as low melting and boiling points. . Step 2: Propagation The next step in the process, propagation, is a repetitive operation in which the physical chain of the polymer is formed. The close packing results in high densities, tensile strength and also high melting and boiling points. Branched chain polymers: In this type of polymers, the monomer units are linked to form long chains which have also side chains or branched chains of different Lengths attached to them. Polyamides and proteins both contain amide linkage.
Which of the following polymers soften on heating and harden on cooling? Polythene, rubber, and nylon 6, 6 are examples of polymers. It involves a number of intermediates such as free radicals, carbocations or carbanions. Its monomer units are of caproilactum. Examples of thermosetting plastics include bakelite, urea-formaldehyde resins. Give an example of an aliphatic biodegradable polyester. Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry. Answer: Polymers are classified into four classes on the basis of molecular forces.
Ans: Polymerization of ethene to polythene consists of heating or exposing to light a mixture of ethene with a small amount of benzoyl peroxide as the initiator. Plastics have intermediate intermolecular forces of attraction. As a result, they also become three dimensional in nature, They do not melt when heated. Fibres are the thread forming solids which possess high tensile strength and high modulus. Which of the following polymers, need at least one diene monomer for their preparation? Synthetic polymers are polymers made by human beings. Fibres: Fibres represent a class of polymers which are thread-like and can be woven into fabrics in a number of ways. A few common examples are starch, cellulose, proteins, rubber nucleic acids, etc.
It has the capacity to absorb large amounts of water. Choose the correct answer out of the following choices: a Assertion and Reason both are correct statements but Reason is not the correct explanation of Assertion. Answer: Natural rubber is a linear cis-polyisoprene in which the double bonds are present between C 2 and C 3 of the isoprene units. A small molecule such as water or hydrochloric acid is eliminated in each condensation. Chemicals in food - preservatives, artificial sweetening agents, elementary idea of antioxidants. Chapter 16: Chemistry in Everyday life Chemicals in medicines — analgesics, tranquilizers antiseptics, disinfectants, antimicrobials, antifertility drugs, antibiotics, antacids, antihistamines.
Most common mechanism for addition polymerisation reactions is free radical mechanism Important Addition Polymers: Condensation Polymerisation or Step Growth polymerization: Polymerisation generally involves a repetitive condensation reaction between two bi-functional monomers. Examples — Cellulose, starch, etc. Out of chain growth polymerisation and step growth polymerisation, in which type will you place the following. What are the polymers with this property collectively called? The monomer units are of the unsaturated hydrocarbon 2-methyl-i, 3-butadiene, also called isoprene. In nearly all cases, the monomers have at least one carbon-carbon double bond.
In other words, the repeating units of homopolymers are derived only from one monomer. Both are co- polymers or mixed polymers. It is used in making sheets, bristles for brushes and in textile industry. They have the high tensile strength and high modulus. Solution: a, c Thermosetting polymers are heavily branched cross linked polymers.
When heated, they become hard and infusible due to the cross-linking between the polymer chains. Group 17 Elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties; compounds of halogens, Preparation, properties and uses of Chlorine and Hydrochloric acid, interhalogen compounds, Oxoacids of halogens structures only. Example:- polyethylene, polypropylene, and polystyrene. Linear chain polymers: In this case, the monomer units are linked to one another to form long linear chains. Polymers are rubber — like solids with elastic properties.
Reason : Neoprene a polymer of chloroprene is a synthetic rubber. Various examples of natural polymer are protein, starch, cellulose, etc. Its monomer units are hexamethylenediamine and adipic acid. Thermoplastics: These are linear polymers and have weak van der Waals forces acting in the various chains and are intermediate of the forces present in the elastomers and in the fibres. For example, nylon 6, 6 is formed by condensation polymerization of hexamethylenediamine and adipic acid. In the condensation polymerisation: The monomer units have specific functional groups present which represent their functionality. Reason R : Polymerisation process induces toxic character in organic molecules.