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Not too technical
May 1, 2008
Hello, I am a little behind in blogging this week so hope you don’t mind a little less technical one tonight.
Continuing along the recent viscosity focus, I measured my first flow curve around 1975 to start my study of polymer melting behavior in an extruder. That is where I first started using the 6 constant equation from an earlier posting. It was also the first time I used an Instron table top rheometer. They are in my mind the best mechanical rheometer due to the gimbaled polymer chamber, but I have not used all the various types of capillary rheometer available. Anyway I like the Instron so much I have two which I use for viscosity measurements. Well one of the reasons I am a little behind in blog input is that this week I measured the most difficult samples I have every measured. Four hot melt samples came a solid blocks which were so sticky it was impossible to handle and too elastic to roll into ropes which could be slid into the melting chamber.
I figured out that they would not stick to Teflon or silicone and I discovered that I could buy a Teflon coated knife (which I did) and I was able to slice chunks off which I melted under vacuum in Teflon coated muffin pans. I intended to pour the samples into the rheometer, but like most melts, they would not “run” and would not easily flow into the rheometer. So using my Taffy making experience (thanks mom) I poured the samples out onto a silicone pie rolling mat into strips which when cooled could be rolled into a rope. But they were still too sticky to touch so I lightly dusted with talcum powder.
Well, after two days of measurements my finger tips were sore from pulling them away from adhesive on all the surfaces of my lab and rheometer which then made the report harder to type! Anyway the results were good so the work was worth it. Now I have just got back from a business trip so am trying to catch up.
This next week I am attending ANTEC, the Society of Plastics Engineers’ Annual Technical Conference (see www.4spe.org) and it will be a very good technical conference. I will give two papers and a short course on Coextrusion and listen to lots of papers on polymer properties, polymer engineering as well as on film technology. If you have never been there is still time to show up and join SPE. I have been attending and participating since about 1976 and would recommend it to you as well. I will send reports next week on some of the better papers while extending the blog information I have been supplying.
Trust all is well at your location and if you have any questions remember you can send to me as a question or comment to the blog or e-mail me (emmount@earthlink.net) and I can add them as subject matter on the Blog.
Posted by Eldridge M. Mount on May 1, 2008 | Comments (0)