User:Matthew R Skorski/Notebook/Cellulose Summer 2014/2014/09/17

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Entry title

Purpose: Create 25 g cast of TiO2 5% and mix 1% filament in Dr. Fox's extruder

Safety and Procedure: Normal large casting, see 6/18/14, but with 250 mL of acetone instead of 200. ________ for Dr. Fox's extruder instructions.

Experimental:

Created a 25 g TiO2 cast

 Mass %	Mass TiO2	Mass ABS
 5.0%	1.2499 g	23.7498 g

Added 250 mL acetone to TiO2. Sonicated from 9:10 am to 9:16 am at 20°C to 23°C. Added ABS and sonicated from 9:16 am at 23°C to 5:10 pm at 34°C. The solution was smooth when poured into the pan, no flecks of ABS were noticed. Heated the pan at 80°C from 5:10 pm to 7:10 pm.

Cut up all the castings from 9/10 and 9/12 into little pieces. Massed total and measured 54.6012 g. Should be about 50 g as 25 + 25 is 50 but apparently something besides TiO2 and ABS was in the castings. It is hypothesized this is acetone leftover from the casting.

Mixed the castings from 9/10 and 9/12 and put them into Dr. Fox's extruder. For each run the TiO2 doped ABS was mixed for 2 minutes at 200 rpm and 195°C. The polymer was then extrudeded and the remains in the machine scraped out between runs. The machine was cleaned with 2 run of 1:2 purge PE at 2 minutes each at 150 rpm and 195°C. The final purge was pure PE mixed for 2 minutes at 150 rpm and 195°C and then cooled to room temperature.

Cleaning the machine was easier than in the summer with the Mn doped TiO2 as the polymer stuck less. However, Dr. Fox did recommend 3 runs of 1:2 purge PE to assist in cleaning out the TiO2 ABS and making it less sticky.

 Mass of run in Dr. Fox's extruder 
 1: 11.42941 g
 2: 10.29732 g   
 3: 10.25085 g
 4: 12.40517 g
 5: 8.00533 g

While extruding the 1% cast through Dr. Fox's extruder took samples too determine if the polymer was breaking down due to the high heat. Samples were taken from the filament extruded, Extrusion, and from the polymer left in the machine after extrusion that needed to be removed, Scrape.

 Mass of samples to examine molecular weight
 Post Cast (PC) 0.04679 g 
 1st Extrusion (1E) 0.05391 g
 1st Scrape (1S) 0.04985 g
 2nd Extrusion (2E) 0.05337 g
 2nd Scrape (2S) 0.04653 g
 3rd Extrusion (3E) 0.04818 g
 3rd Scrape (3S) 0.04213 g
 4th Extrusion (4E) 0.05305 g
 4th Scrape (4S) 0.04527 g
 5th Extrusion (5E) 0.05610 g
 5th Scrape (5S) 0.05505 g

Cut up the filament from Dr. Fox's extruder and put it through the Filabot extruder. The filament came out well, it kinked a bit near the top end but flowed well overall. Once the polymer ran out in the hopper the filament seemed to get thinner and extrude slower. The filament came out a greyish color, surprising as the color of the polymer after Dr. Fox's extruder was an off white.

The casting made on this day did not have a homogeneous appearance. White spots are apparent on the casting. These may be small accumulations of TiO2 that aggregated during the casting process. The spots look like leopard prints.

Figure 1: The second run right before scraping. Little sticking is seen.

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Figure 2: The fifth run right before scraping. Notice the build up of residue.

20140917 132615 (1).jpg

Figure 3: Filament being extruded from Dr. Fox's extruder. The color is an offwhite tan.

20140917 132027.jpg

Figure 4: 5 % casting after heating. The nano particles appeared to aggregate and make leopard spots.

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