Chapter 16, Problem 16.1P

Interpretation Introduction

Interpretation:

The terms linear and branched polymers are to be described. Also, it is to be stated if thermoplastics can be branched.

Concept Introduction:

Polymers are the large molecules which are made up of many small repeating units bonded together in linear, branched or cross-linked manner.

They are of two types: natural and synthetic. Natural polymers are those which occur naturally, and synthetic polymers are those which are synthesized or man-made.

Answer to Problem 16.1P

Linear polymers are straight chains of polymers made up by carbon-carbon bonds.

When branching occurs in this straight chain, branched polymers are formed.

Thermoplastics can be branched polymers which can be remolded by temperature change.

Explanation of Solution

Linear or straight-chain polymer are those which are made up of long chain of carbon-carbon bonds. The geometry around each of the carbon in this type of polymer is tetrahedral and physically the chain is neither linear nor straight. Examples of this kind of polymer are polyethene, Teflon, polypropylene, etc.

When some of the units form branches on this linear chain of polymer, then the resulting polymer is known as branched polymer. These branches are not linked to any other branch. Examples of this kind of polymer are starch, glycogen, etc.

Thermoplastics are a type of branched polymer being associated to each other by intermolecular forces which weakens when the temperature is increased and helps in remolding of the polymer plastic. As the polymer is cooled, it hardens again retaining its shape.

Conclusion

Linear polymers are straight chains of polymers made up by carbon-carbon bonds. The occurrence of branching in this straight chain results in formation of branched polymers. Thermoplastics can be branched polymers which can be remolded by temperature change.