University of Connecticut |
Polymer Program/Chemical Engineering Dept. Joint SeminarReactive Processing of Polymer Nanocomposites: Experiments and Modeling New Jersey Institute of Technology Tuesday, April 13, 2004 11:00 am , UTEB 150 In a reactive extrusion process, the synthesis or modification of a polymeric material takes place simultaneously with the processing and shaping of the final product. This is an efficient method for continuous polymerization of monomers and chemical modification of existing polymers, and is viewed as a complex reaction engineering process that combines the traditionally separated operations, i.e., polymer chemistry (polymerization or chemical modification) and extrusion (blending, compounding, structuring, devolatilization, and eventually shaping), into a single process in a screw extruder. Chemical reactions, such as bulk polymerization, graft reaction, inter-chain copolymer formation, coupling/crosslinking reactions, controlled degradation, functionalization, and reactive blending, have been performed successfully with reactive extrusion. We have applied this processing technique to polymer-based nanocomposites. This presentation will discuss several components of our studies on reactive processing of polymer nanocomposites, starting with a discussion on some relatively new experimental results on reactive modification of the impact properties of polypropylene filled with nanoclay particles. This will be followed by a discussion of some recent results on numerical simulation of failure mechanisms in nanoclay and carbon nanotube reinforced polymer composites. In particular, the effect of a third phase on failure mechanisms of nanoclay filled, and the effect of fiber orientation in carbon nanotube reinforced composites, will be discussed. The talk will end with a comparison between the predicted results of polymerization progression in a twin screw extruder based on 1D and 3D modeling. This last part of the presentation will be illustrated with the reactive extrusion of e-caprolactone, a polymer that is commonly referred to as a model polymer for reactive processing, because of its extraordinarily large heat of reaction.
This seminar series is sponsored by generous grants from U.S. Surgical Corporation and Rogers Corporation. |