Polymers

Bakelite is cross linked polymer of formaldehyde and novolac. Novolac is linear polymer of phenol-formaldehyde.

Glyptal, Dacron & PHBV are polyesters.

Novalac is copolymer of phenol & formaldehyde but not polyesters.

Only 1° aromatic amines give stable diazonium salt on reaction with nitrous acid

Here 1° aromatic amine is  which gives most stable diazonium salt

Novolac is linear polymer of o-hydroxymethyphenol

Given let α, β be the roots of the equation x² + bx + c = 0

So, ${\alpha }^2+b\alpha +c=0\&{\beta }^2+b\beta +c=0$

Also x² + bx + c = (x - α) (x - β)

$NowL=\underset{x\to \beta }{lim}\frac{e^{2\left(x^2+bx+c\right)}-1-2\left(x^2+bx+c\right)}{{\left(x-\beta \right)}^2}$           

$\underset{x\to \beta }{lim}\frac{2{\left(x-\alpha \right)}^2{\left(x-\beta \right)}^2+\frac{8}{6}{\left(x-\alpha \right)}^3{\left(x-\beta \right)}^3+........}{{\left(x-\beta \right)}^2}$

=  $2{\left(\beta -\alpha \right)}^2=2\left[{\left(\beta +\alpha \right)}^2-4\alpha \beta \right]=2\left[b^2-4c\right]$

Monomer of novolac is

Molecular mass of monomer unit

              = 12 × 7 + 1 × 8 + 16 × 2

              = 84 + 8 + 32

FeCl₃. 3H₂O i.e. [Fe (H₂O)₃], K₃ [Fe (CN]₆ and [Co (NH₃)₆]Cl₃ the last two complex are inner-orbital complex due to presence of strong ligand.

$\therefore {\Delta }_{0}of{K}_3\left[Fe{\left(CN\right)}_6\right]>{\Delta }_{0}of\left[Co{\left(N{H}_3\right)}_6\right]C{l}_3$

Because CN^- is strong ligand

$\therefore {\Delta }_0\propto \frac{1}{\lambda }$

More ${\Delta }_0$ smaller value of absorbed $\lambda$

$K_3\left[Fe{\left(CN\right)}_6\right]\to F{e}^{+3}=4s^{0}3d^{5}4p^0$

$\therefore u.e=1$

$\therefore \mu =\sqrt[]{1\times \left(1+2\right)}B.M=\sqrt[]{3}B.M$

= 1.732 B.M

$\approx$ 2

Bakelite formed by the condensation reaction of phenol with formaldehyde and it is a thermosetting polymer/ plastics.

Monomer of novolac is

Molecular mass of monomer unit

= 12 × 7 + 1 × 8 + 16 × 2

= 84 + 8 + 32

= 124 g

Molecular mass of polymer = 963 g

$\therefore$ n × mass of monomer = mass of polymer + (n – 1) × 18

(n – 1) unit of H₂O is removed during formation

$\therefore 124\times n=963+18\left(n-1\right)$        

106n = 945

$\therefore n=\frac{945}{106}=8.91\approx 9$

Melamine + formaldehyde ->  Melamine formaldehyde polymer