Polymer Journal Entry #3

With the final adjustments of the polymer, it is beginning to work well with our design goal. Getting to the point of the finished project was harder than expected, lots of surprises came along the way.

My first prototype was a absolute failure. The turnout was a green clear liquid that was like jelly. On the inside, there were clumps of corn starch and guar gum. On the outside, everything was very runny. Making this prototype, I first added 15 mL of liquid starch into a small cup. After that i added four drops of green food dye. Once mixed all the way through I added seven mL of PVA and then 3 grams of cornstarch. After I mixed it all together, I soon came to the conclusion that my liquid starch to PVA solution and cornstarch was completely off. I know that because when I added in the PVA, the jello wasn’t forming properly, and it ended up as much more liquid. I had also added them in the wrong order causing the clumps to form. The result was a super slimy, not very sticky, jelly substance. The results for the blob and hang test were what I was hoping for, they lasted a very long time and stayed molded. However with the bounce test, it bounced up approx. two inches off the table.

After tweaking the procedure, my second prototype was a success. This time I first added 5mL of liquid starch, then only three drops of food coloring all in a plastic cup. After that I added 10mL of PVA solution followed by 1.7 grams of cornstarch. Before I added the guar gum, the polymer was very sticky and stringy. It wasn’t the texture I was hoping for; however, after the guar gum was added, it became much more elastic. It still contained its stickiness, but it was less extreme and easily molded. With the tests, the polymer had no bounce at all, took 47 seconds in the hang test, and 1 minute and 21 seconds in the blob test. To test it out, I stuck it onto a metal water bottle, and it stayed molded without dripping for five minutes before we had to take it off


image from here

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