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Polymers — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryPolymers2 Marks
Question
Phenol and formaldehyde undergo condensation to give a polymar (A) which on heating with formaldehyde gives a thermosetting polymer (B). Name the polymers. Write the reactions involved in the formation of (A). What is the structural difference between two polymers?
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Answer


Polymer ‘A’ is Novalac and ‘B’ is Bakelite. The reactions involved in the formation of these two polymers are given below:



Novalac on heating with HCHO undergo cross-linkage to form an infusible solid called Bakelite. Novolac is linear chain polymer while Bakelite is cross linked polymer.

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