where Xcscrystallinity; r0sdensity of 100% crys-
talline PP 0.936 grcm3.; rasdensity of amorphous
PP 0.852 grcm3.; rcsdensity of PP blends.
A little of the PP, cut from the impact samples, was
placed between two slide sheets and a certain pressure
applied. The whole system was heated to 2308C toallow complete melting of the film samples under pressure,
then the pressure was released and the film
samples were quenched in air to simulate the process
of non-isothermal crystallization. To observe the effect
of heat treatment on spherulite size, tests were carried
out on the film samples above, according to the technology
of the above succeeding heat treatment.
The polar microscope photos of the film samples and
their samples which underwent heat treatment were
made to measure the spherulite size, and then
number-average of the spherulite size Dn. was calculated
by the following relation