Polymers/Properties

Tacticity (stereochemistry) can change the properties of the polymer.

Molecular mass

Number average (Mn) and weight average (Mw).

$$ M_n=\frac{\sum M_i N_i} {\sum N_i},\quad M_w=\frac{\sum M_i^2 N_i} {\sum M_i N_i},\quad M.W.D. or PDi=\frac{M_w} {M_n} $$

Glass transition (Tg) and melting temperature (Tm)


 * Tm: crystalline regions, first order transition
 * Tg: amorphous regions, second order transition


 * hydrogen bonding increases Tg
 * longer side chains lowers Tg
 * at or below Tg, the ratio of free volume to total volume of polymer is constant