In many polymer manufacturing operations, the material is processed near the glass transition temperature (Tg). Examples are thermoforming, blow molding, film blowing, hot embossing, forging, plastic welding, and de-airing in safety glass lamination. In these processes, solid-like behaviors such as strain hardening and yielding play important roles. These material properties cause the material to flow (or deform) in a way that substantially differs from a polymer melt. In order to understand the flow behavior near the Tg, polyvinyl butyral (PVB), a rubbery polymer used in safety glass lamination, was studied in this work. The flow properties of the polymer above the Tg were characterized by using both shear and elongational rheometers, and a tensile tester. The measured flow properties were described by a viscoelastic constitutive model.
All Science Journal Classification (ASJC) codes
- 化學工程 (全部)