成型培训Polymer Processing.ppt

Polymer Processing Legacy Lecture of Fall 2000 Not just one polystyrene Back to the Beginning Compression Molding Injection Molding Blow Molding—e.g. milk bottle Four-roll calender A Plastics Extruder—e.g. tubing Fiber Drawing Wet Spinning (e.g. Kevlar) Cotton Dry Spun Acetate Need tenacity vs. ElongationPlot—a Student Project like Billmeyer 18-1 Fiber properties for textile use * References Billmeyer* Ch. 17, 18 Elias** Ch. 14 *Textbook of Polymer Science 2nd Ed. Wiley-Interscience, New York (1962,1971) **An Introduction to Polymer Science VCH, New York (1997) This lecture was contributed by the MS-I class of Fall 2000. Left to Right Nhan Thai, Lee Madsen, Lu Ziqiang, Zu Yichuan, Nikhil Gupta Simon Mwongela, Andrea Dupre, Mariah McMasters, Vera Verdree, Angela Davis Nadia Edwin, Thomas Morgan, Amy Morara, Xiaoming Liang Missing: Justin Mecomber Selected PS grades from BASF. VEF=very easy flow; HM=high molar mass; HR = heat resistant. Taken from Elias, Ch. 14. Processing engineers select grades using data such as these, perhaps relying on such numbers more than the molecular data such as M or Rg that chemists are used to. Note how completely unmolecular! What molecular properties do you suppose correspond to EF, HR or HM? Early in the course, we tried several ways to categorize polymers, such as condensation vs. addition, etc. From a processing point of view, the main classes are: Thermoplastic: the resin is heated to make a viscous liquid and then processed into a usable object without much additional chemistry. Example: polyethylene, polystyrene. Thermoset: upon heating, further reaction occurs to make molecules “set up” into a useful product. Chemistry occurs, so these are sometimes called “reactive polymers”. The resin may be provided as either small molecules or “prepregs”—partially polymerized stuff. Example: polyurethanes, phenol-formaldehyde, melamine-formaldehyde, epoxy glue. Redrawn by Nikhil Gupta and Yichuan Xu from Billmey