filament extrusion with highly loaded powder content

At my job, I'm supposed to make some filament with highly loaded titanium oxide powder for research purposes. We're trying to get as much of this stuff into filament as possible. We've tried ABS, which works, but not very well. PLA is next candidate, possibly nylon. But I'm more concerned with the methodology we're using to get this done. We've tried to dissolve the polymer/powder and precipitate them. Also tried to dry mix the powder with the pellets into the extruder directly, which didn't work very well. The former is too costly, the latter we don't really have the equipment. So I'm just trying to get ideas on ways that this can be executed economically and effectively. Also, trying to figure out what additives (eg. plasticizers) would be good ones to try.

any suggestions that might point in the right direction would be appreciated. Thanks

Hi Alang
You don't say what you are trying to achieve (other than a high load of filler), what equipment you have, or your knowledge of polymer chemistry. all this would help us help you.

Also what is the problem so far, is it uneven distribution of the TiO2 or some other problem. I am not an expert have about 2 decades of formulating resin systems so I might be able to help.

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Originally Posted by alang

At my job, I'm supposed to make some filament with highly loaded titanium oxide powder for research purposes. We're trying to get as much of this stuff into filament as possible. We've tried ABS, which works, but not very well. PLA is next candidate, possibly nylon. But I'm more concerned with the methodology we're using to get this done. We've tried to dissolve the polymer/powder and precipitate them. Also tried to dry mix the powder with the pellets into the extruder directly, which didn't work very well. The former is too costly, the latter we don't really have the equipment. So I'm just trying to get ideas on ways that this can be executed economically and effectively. Also, trying to figure out what additives (eg. plasticizers) would be good ones to try.any suggestions that might point in the right direction would be appreciated. Thanks

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It'd be worth poking around on google scholar for this issue. Lots of literature on homogeneous mixing, but finding the right key may take some time. One thing that may be a dead end, but may be worth looking at is whether the process of mixing has to be done at the hopper (which is rather uncontrollable), or whether the powder can be introduced in the extrusion pathway after the pellets have been melted down.

If your problem is uneven distribution of the TiO2 you should try making and using a ball mill, essentially a strong barrel about 1/3 full of large 25 to 75mm diameter balls made of stone ceramic or other hard material. You put the material to be milled and mixed into the barrel with the balls then rotate the barrel on its side warning it takes a long time overnight at least and makes a lot of noise. With your materials a small amount of water might help. pre-grinding the plastic pellets would helpThis is the standard way of mixing fillers into resin to make paint