HOW TO DETERMINE HIGH GROWTH SPEEDS IN POLYMER CRYSTALLIZATION

With the fast crystallizing polymers HDPE and i-PP it is extremely dif ficult to extend the range of measurements of the growth speed of sphe rulites to temperatures as low as 80 degrees C. So far the lower limit for these measurements has been about 120 degrees C for both polymers . Several possibilities for this kind of measurements are explored in the present paper. It appears that none of these measurements is witho ut uncertainties. So, only the comparison of results, as obtained with several independent measurements and with theory furnishes a sufficie nt credibility. Optical measurements, from light scattering to visual inspection, all under very special conditions of heat transfer, are de scribed.