Predictions: I predicted that when we combine the Sodium Borate with the Poly Alcohol that a thick slime will be made and the volume will change.

Transcription

1 Braden Monteyro Due:February 7, 2016 Polymers and Cross Linking Introduction: This lab was completed February 7, My lab partner was David. In Phase 1 of this lab we combined two reactants, Polyvinyl Alcohol and Sodium Borate, to form the product slime. During Phase two we used an analogical method using paperclips to help understand what was happening within the reaction and between the molecules. Phase three we designed an experiment pertaining to slime to answer a question. This lab is important to help build experimental design skills and to use analogies for better understanding. Using the Analog to Target method gave me a way to relate what I was learning to something I could see. Even though it was a simple relation it helped me visualize how the microscopic and macroscopic behavior of molecules work. Data: The procedure for Polymers and Cross Linking: a CORE learning cycle lab was downloaded from ICN on February 1, For Phase 2 of this lab, we used paper clips as an analogy. The Analog to Target Worksheet is attached. During Phase 3, we designed and performed our own experiments. The Designing Experiments Worksheet is also attached. Predictions: I predicted that when we combine the Sodium Borate with the Poly Alcohol that a thick slime will be made and the volume will change. Observations: My observations are in my lab book in the form of the Q s that occurred throughout the lab. Also my Figure 1 and Figure 2 from the lab are both accessed in my copies from my lab book and will be attached to the bottom.

2 Quantitative Data: Polyvinyl Alcohol Sodium Borate Water Mass of Graduated Cylinder Mass of Graduated Cylinder with Solution 32.02g 32.02g 32.02g 61.33g 61.78g 61.23g Mass of Solution 29.31g 29.76g Volume of Solution 30mL 30mL 30mL Density of Solution 0.977g/mL g/ml.974 g/ml Phase 3: Observations and Comparisons Slime with 2mL of Sodium Borate and 20mL of Poly Alcohol Forms looser gel that has excess poly alcohol Slime with 5mL of Sodium Borate and 20mL of Poly Alcohol Forms a uniform gel with little to no excess of either the Sodium Borate or the Poly Alcohol Slime with 10mL of Sodium Borate and 20mL of Poly Alcohol Forms a non uniform gel that has excess sodium borate. The gel seems almost chunky. Analysis: During Phase 1, we added 5 ml of Sodium Borate to 20 ml of Polyvinyl Alcohol. After stirring the reactants, a slime was produced. This slime was much thicker than water and was much more congealed. When we tried to pour it into a funnel, it quickly got stuck and didn t pass through without the assistance of something to push it through. In Phase 2, we used an Analog to Target Worksheet in order to visualize what was happening between the two reactants. The long chains of the polyvinyl alcohol were being held together by the cross linker, sodium borate. The analogy used was paperclips. The individual chains (representing polyvinyl alcohol) and the individual paper clip (representing sodium borate) separately passed through the funnel with no problem. However, as these two were combined with increasing proportions of cross linking paper clips, the chains were getting held together tighter thus, the molecules of paperclips had a harder time passing through the funnel similarly to the slime we created in Phase 1. In our own experiment, shown on the attached Designing Experiments Worksheet, we wanted to test how different quantities of Sodium Borate

3 would react with a constant amount of Poly Alcohol (20 ml). When we used 2 ml of Sodium Borate,The slime was not as congealed and produced a small amount of slime and excess liquid. This version of the slime passed through the funnel better than the slime with 5 ml of NaB. We also made a slime with 10 ml of Sodium Borate. This produced a slime and extra fluid. I claimed that as more Sodium Borate is added to a constant amount of Poly Alcohol, the slime will become more congealed. When compared to the original slime, the three from my designed experiment show that as more Sodium Borate is added, the more congealed and less fluid the slime becomes. Compared to the analogy of the paper clips, you would see that as you added more cross links, the polymers would be held together tighter. As the polymers are held tighter together the more congealed the solution becomes. Claim: After observing the data I obtained from the lab, I can conclude that as more Sodium Borate is added to Polyvinyl Alcohol, the resulting slime will be thicker. This claim was supported during my experiment because when compared to Phase 1, the different amount of Sodium Borate was accounted for in the change in the thickness of the solution. When there was less Sodium Borate added there was more fluid and when there was more Sodium Borate added it was more congealed. As increasing amounts of Borax was added, the slime became more and more viscous. The evidence I gained through experimentation in Phase 1 and Phase 3 supports my claim that as more Sodium Borate is added to a constant amount of Polyvinyl Alcohol, the more gelled the mixture will become. Attachments:

4 Figure 1 Figure 2

5 Analog to Target Worksheet

6 Designing Experiments Worksheet

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