CHEMISTRY TEXTBOOK

OH

CH 2 OH

Stage 2 :

(Novolac)

OH

CH 2

OH

CH 2

OH

H⊕ H^2 C CH^2

n -H 2 O

Stage 3 :

(Bakelite)

Novolac

CH 2

CH 2

CH 2 CH 2

OH OH

OH

CH 2

OH

CH 2

OH

CH 2

CH 2

OH

CH 2

CH 2

H 2 C

H 2 C

OH

CH 2 OH

OH

CH 2 OH

OH

+ CH 2 O Acid + +

(Phenol)

Stage 1:

(Formaldehyde) CH

2 OH

OH

CH 2 OH

CH 2 OH

HOH 2 C

or base

Fig. 15.3 Preparation of Bakelite

N

N

H 2 N NH 2

NH 2

N

N

N

(HOH 2 C)NH NH(CH 2 OH)

NH(CH 2 OH)

+ CH 2 O N

(Melamine) (Formaldehyde)

(cross linked melamine formaldehyde resin)

H 3 O⊕

N N

N

N - CH 2

N n

N

H

H H

H 2 C

H 2 C

Fig. 15.4 Formation of cross linked melamine formaldehyde resin

CH 2 = CH - CH = CH 2 + C 6 H 5 CH = CH 2

1, 3 - butadiene

(75 %)

Fig. 15.5 Formation of SBR (Buna - S)

(SBR)

styrene

(25 %)

C 6 H 5

CH 2 - CH = CH - CH 2 - CH 2 - CH = CH - CH 2 - CH 2 - CH - CH 2 - CH 2 - CH = CH