Polysiloxanes: paradigm or paradox

✍ Scribed by Joseph H. Magill

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 419 KB
• Volume: 19
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/(sici)1521-3927(19980101)19:1<65::aid-marc65>3.0.co;2-y

✦ Synopsis

Spherulitic growth rates and physical properties of polysiloxanes are well correlated for a wide range of molecular weights. Below the zero shear entanglement molecular weight, M,, chain folding is probably the norm and fractions are brittle, but after M, is traversed there is a significant decrease in crystallinity, increase in interfacial surface energy and change in lamellar morphology as polymer fractions go from brittle to tough. The chain folded crystallization model with reptation, as a chain folding facilitator, fails to account for this behavior. Appropriate property data for polyethylene and polyisoprene fractions also supports this thesis which now appears to be more of a paradigm than a paradox.