AzoMittle Posted March 4, 2016 Share Posted March 4, 2016 (edited) EDIT: I went ahead and put in a small order for some DBP and virgin polystyrene beads and virgin ABS pellets. I'll try out different combos and such, best way to see how it works is to try it I'm figuring. I want to experiment with using polystyrene and ABS as binders. I plan to use a plasticizer such as dibutyl phthalate (DBP) or diethyl phthalate (DEP). So a few questions, first, is all polystyrene / ABS created equal or do some contain other things? Second, would a potassium hydrogen phthalate (KHP) solution work as a plasticizer? I'm working on this based on some patents and similar documents. I suspect the author originally used a Kraton G thermoplastic elastomer (TPE). Is there a source for it or similar? The main North American distributor is PolyOne, they only sell bulk wholesale to registered businesses. It was most likely G-6500 which is block copolymers of styrene and ethylene/butylene: http://imgur.com/bpmt0a0 Edited March 4, 2016 by AzoMittle Link to comment Share on other sites More sharing options...
Arthur Posted March 4, 2016 Share Posted March 4, 2016 The Phthalate esters are suspected of unpleasantness in the body. They are also permanent softeners they make PVC compounds feel flexible to floppy according to compound variables, and the product stays that soft for life. So IMO if you get a comp soft enough to work then it's too soft to form into rigid items -stars etc. Link to comment Share on other sites More sharing options...
PIL Posted March 4, 2016 Share Posted March 4, 2016 KHP solution is not a plasticizer. And you don't need to make the stars flexible. Polystyrene is RICH in carbon. Soot which comes from the incomplete combustion mess up the color easily.You may need extra oxidizer to compensate for the increased fuel value. 1 Link to comment Share on other sites More sharing options...
AzoMittle Posted March 4, 2016 Author Share Posted March 4, 2016 KHP solution is not a plasticizer. And you don't need to make the stars flexible. Polystyrene is RICH in carbon. Soot which comes from the incomplete combustion mess up the color easily.You may need extra oxidizer to compensate for the increased fuel value. Thank you, I wasn't sure about the KHP but it is much cheaper than DEP, DBP, DNOP, etc. so I figured it was worth asking. I'm not worried about soot or color, it's a white. Thanks for the heads up on oxi:fuel. Also, I'm not trying to make the stars flexible; author states it is to control the melting point making it less likely to develop cracks as well as make the comp easier to handle, similar to screening in lampblack I'm presuming. They also mention it as a way to remove and/or limit solvent vapors from the production process. Arthur, any suggestions for other plasticizers that are kinder on the body? I have a polymer reference book that lists several plasticizers commonly used for polystyrene, I'm open to using them. "Polybutenes, paraffin and zinc stearate, di- and tri-isopropylbiphenyls, dioctyl sebacate, mineral oil, paraffinic mineral oil, and polyol as a compatibilizer." Link to comment Share on other sites More sharing options...
Zingy Posted March 4, 2016 Share Posted March 4, 2016 (edited) I have found the most workable form of polystyrene is artificial snow, sold in art and craft stores around Christmas. Immediately after it retails up to ninty present off, the standard price Most artificial snow contains a fire or flame suppressent, so you have to carefully read the labels. The artificial snow can be ball milled to a very fine more condensed powder The heat from a food processor, such as a blender causes it to stick to the side of the container. Powdered polystyrene greatly increases the burn rate of powdered benzoate whistle mix, with a white flame. Polystyrene disolves readily in toluene, to make a plastic glue, simular to plastic model glue. Polystyrene maybe useful for small end burning whistle fuel rockets, to enhance the boosting whistle fuel mixture in small shells. I hope some of this information is of assistance. Edited March 4, 2016 by Zingy Link to comment Share on other sites More sharing options...
schroedinger Posted March 4, 2016 Share Posted March 4, 2016 (edited) Azo an other possible plasticizer is camphor. Remember that you only need 0.5-2% of plasricizer. Making the stars just a little flexible (not bendable) could also help if you use a hard break, as the star could absorb some power, where other stars would break. But why don't you use phenolic resin and hexamine? Edited March 4, 2016 by schroedinger Link to comment Share on other sites More sharing options...
AzoMittle Posted March 4, 2016 Author Share Posted March 4, 2016 (edited) Azo an other possible plasticizer is camphor. Remember that you only need 0.5-2% of plasricizer.Making the stars just a little flexible (not bendable) could also help if you use a hard break, as the star could absorb some power, where other stars would break. But why don't you use phenolic resin and hexamine? I'm not using phenolic and hexamine because I know how that works, this is about trying something different. Camphor is a great idea! I'll try that. The patent suggests around 10-20% binder by weight with good results between 14-16%, plasticizer is present at around 50%--up to 80%--of the weight of the binder. Both of these seem rather high to me but then again I haven't tried them yet. Recommended percentage is based on polystyrene and DMP. Edited March 4, 2016 by AzoMittle Link to comment Share on other sites More sharing options...
Arthur Posted March 4, 2016 Share Posted March 4, 2016 I remember a product called reophos as a plasticiser for PVC Link to comment Share on other sites More sharing options...
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