At Walt Disney World in Orlando, you can go on a trip inside Spaceship Earth, the huge geosphere with mouse ears in the logo. You travel upward in an open train of little cars and see the history of communication unfold from cave drawings to computers. (You can see it for yourself in this 10-minute video.) Then the train turns around and you go backwards down the inside of the sphere, as you look up at the stars in the sky and a voice talks about the future. The backwardness is necessary for the ride down—if we faced forward, we’d fall out of our seats—but in real non-Disney life, I want to face the future with eyes, ears and mind wide open. That’s one reason I went to the Society of Plastics Engineers’ Annual Technical Conference (SPE’s ANTEC) in Anaheim, CA, last week.
It’s over now but you still can “attend” by accessing the listing of 124 extrusion-related papers given at this conference, with primary authors, affiliations and descriptive titles, in last month's column.
So, what did I learn at ANTEC? Here are a few areas of importance:
Tiny. Very tiny nano-materials have been around for a long time now, and can be too easily pushed aside by processors as too expensive and exotic, suitable only for special uses. It ain’t necessarily so. The huge surface area they offer can mean big changes in gas and moisture barriers to many substances, in electrical and chemical properties and, in coextruded layers, surface properties, as well. A nanometer, by the way, is one billionth of a meter. Very tiny.
Bioplastics. The buzz about bioactive polymers is still around but fading, as we learn that the environmental benefits they appear to offer (their greenness, if you will) are wanted mainly by big retail brands to appeal to their consumer base, as long as they don’t cost too much or degrade product performance. This drags in some biobased polymers, too, which may or may not be bioactive. What I’m still looking for (but don’t expect to find at a public conference like this) is a fully biobased PET at no added cost compared with a petroleum-based material.
Lab equipment. As the SPE is heavily academized, the exhibition area had a lot of lab equipment, including a tiny twin-screw compounder making a testable filament from a few grams of polymer. My favorite lab tool was shown, too: A torque rheometer, which can show thermal stability as well as melting behavior and dynamic viscosity.
Screw design and materials. Several papers dealt with this topic, including what causes screws to break in service. This is most important to buyers of new and rebuilt equipment, who should discuss design, dimensions and materials of construction in advance, if possible. They also should consider specific resin properties (not just resin families like PE or PVC) and extruder operating conditions, and apply computer simulations where resin viscosities and machine size make it worthwhile. For the rest of us who use existing equipment, it is still good to measure what we have and to know what it can do, with and without