Study on polypropylene-polyethylene-based copolymer solidification

摘要

In the present work, nonisothermal crystallization is analyzed. Concretely, we study the solidification process of polypropylene-polyethylene-based copolymers by means of differential scanning calorimetry (DSC). Several samples with different additives are subjected to artificial aging processes. The calculation of the specific surface energy, sigma, is in good accordance with the results reported in the references. The artificial aging is responsible for a slight increase of sigma values (i.e., increase of 1.6 kJ . m(-2) for sample A and 0.3 kJ . m(-2) for sample B). On the other hand, the sigma value of sample B is considerably lower than that of samples A, C, and D (i.e., 17.3 kJ . m(-2) for sample B versus an average value of 23.0 kJ . m(-2) for the other samples). Microstructure analysis was performed by scanning electronic microscopy (SEM). As shown from the analysis, aging only affects superficial zones because no changes in the morphology of the central zone were detected in the different samples. Sample B shows a different behavior; it was less resistant to fracture. From DSC and SEM measurements, we can state the additive influence on the original sample behavior as well as on the solidification process of polypropylene-polyethylene-based copolymers. (C) 2000 John Wiley & Sons, Inc. [References: 18]