A study of the morphology and physical properties of polypropylene films

✍ Scribed by George W. Schael

• Publisher: John Wiley and Sons
• Year: 1966
• Tongue: English
• Weight: 658 KB
• Volume: 10
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1966.070100607

✦ Synopsis

Data are presented showing that rapidly quenrhed polypropylene film contain a paracrystalline phase in addition to crystalline and amorphous phases. The density of the paracrystalline phase was found to vary between 0.8890 and 0.9080 gJcm.3. Other data show that the density of quenched polypropylene films increases during aging, the increase being a linear function of the logarithm of the film age. The physioal properties of the films, secant modulus, impart strength, and coefficient of friction, were found to vary not only with crystallinity, i.e., romposition-dependent density, but also to vary during aging nhen the density was increasing with little change in cry&dlinity. An example of this dependenre is the increase in secant modulus of 10.9 X lob p~i/g./rm.~ during aging and only 3.7 X 106 psi/g./cm.3 as the crystallinity increased. Because of the three phases and the density-time change, it is possible to have films with the same density and different physical properties and, conversely, films with the same physical properties and differe n t densities.