Plasticization, in general, refers to a change in the thermal and mechanical properties of a
given polymer which involves: (a) lowering of rigidity at room temperature; (b) lowering of
temperature, at which substantial deformations can be effected with not too large forces ;
(c) increase of the elongation to break at room temperature; (d) increase of the toughness
(impact strength) down to the lowest temperature of serviceability. These effects can be
achieved: (1) by compounding the given polymer with a low molecular weight compound or
with another polymer: and (2) by introducing into the original polymer a comonomer which
reduces crystalli zability an d increases chain
flexibility.