Thursday, March 3, 2011

Sodium Silicate Polymer Lab Investigation

Problem: How do you make a sodium silicate polymer?

Hypothesis: When the ethyl alcohol is intermingled with the sodium silicate, the two will for a polymer via one providing the long chains, and the other providing as a cross-linker.

The main materials in this experiment were sodium silicate (approximately 20 mL) and 3 mL of ethyl alcohol. The procedures, in a round-about explanation, were equivalent to the following:

Measure 20 mL of sodium silicate with a gradual cylinder and pour it into the 200-250 mL beaker.

Quantify 3 mL of ethyl alcohol in a second beaker (one that had been empty prior to the alcohol and also holds the same quantities of 200-250 mL). This solvent was to be measured in the same gradual cylinder as the one used in advance. However, it is crucial to clean it out each time it is used, otherwise the mixture of solvents and solutes may cause a difference in chemical properties, thus disrupting the entire experiment. Note that alcohol is flammable, and needs to be handled with care, as does the sodium silicate.

At a steady pace, pour the alcohol into the beaker with the sodium silicate.

A stirring stick will be utilized in this next step. With a descent circular motion, stir the two solvents together to form a mixture that resembles tightly compacted snow.

With the forefinger and thumb on both the right and left hand, gently mold the solid mass into a sphere. To receive the best results, run the ball under flowing water for approximately 30 seconds while tightly shaping the polymer.

Use the Rebound and Temperature Test to calculate chemical and physical properties of the polymer, and use process of elimination to determine why this reaction occurred. Observe all worthy observations

Rebound and Temperature Test Procedures: The rebound and temperature test allows scientists in-the-making to chronicle the physical and chemical properties of a polymer. The only materials needed for these two tests are one 30 cm ruler, a flat surface such as a completely horizontal table, and a typical refrigerator (with temperatures at approximately 1.7 to 3.3 degrees Celsius or 35-38 degrees Fahrenheit). In order to test out the heated (more or less likely to be room temperature), vertically hold the ruler so that the 30 cm mark is at the top, and 1 cm mark is on the bottom. Mold the polymer in the shape of a ball for accurate and consistent ramifications. From the top of the ruler, drop the ball and observe how high and in which specific direction it bounced. Repeating this process several times is a recommended solution when trying to find a reliable average height; reform into a ball after each test if needed. Record conclusions, especially why this event occurred and what the exercise proved. To evaluate how a frigid environment affects the polymer’s chemical properties, place the polymer (still in the shape of a ball) in the center of a shelf (if possible), and wait for roughly 10-15 minutes. Once the substance has been able to settle in the refrigerator, re-alter the shape so that its mold is consistent, and eliminates any distorting variables. Reiterate the process used for heat. Record vital results.

Results and Conclusion from Sodium Silicate Polymer: From what was able to be seen from the naked eye, the solution of the ethyl alcohol and the sodium silicate has aroused several complicated, yet simple reactions. First off, when the ethyl alcohol was added to the silicate, already there were white specks, about half of a centimeter in length, that were forming on the surface of the liquids. It seemed as though the long (at least for the scientific branch of chemistry) chain were commencing their transformation, and preparing for the cross-linkers. This was when the chemical reaction was first recognized. Once stirring was initiated, there was roughly a 10-20 second delay before the two solvent morphed into one solute. This specific solute could be described as compact snow with a odorous fragrance of rubbing alcohol. In addition to this sense-stimulating expedition, concurring physical (caused by chemical reactions) features include having a moderate plastic texture, similar to the inside of a rubber bouncing ball, as well as a impressionable glossy sheen to its exterior. This glossy sheen is due to its extensive excursion in the classroom sink under cool to room temperature water, which being shaped into the proper mold (a sphere) for the rebound test. While Keara molded the newly made polymer in the sink, a foul odor emitted from the used water, and was hypothesized to be the residual components of the ethyl alcohol. This was the most reasonable explanation, considering that the alcohol was the cross-linker, and not all of the cross-linker is needed to be used depending on the amount of monomer chains formed from the silicate. There is, as there are for so many others in the scientific field, a logical axplication for these somewhat odd occurrences. The silicon atomic structure is simple and is only bonded to four oxygen atoms, disabling linkage in any specific areas. The ethyl atoms are even less complicated; they only contain two carbon atoms. Nevertheless, when the two are combined, with a little help from the stirring rod, the silicon branches out (with the side branches that mature polymers contain) to form the long chains, while the rivaling hydrous fluid enables interconnection because it acts as a cross-linker. These ethyl groups are additionally substituting for previous oxygen atoms.

Once this was accomplished, a ruler was utilized to estimate approximately how high the silicate ball could bounce due to its substance alteration (from where it would be dropped onto a flat surface such as a level table from 30 cm). After the first bounce, which was documented at a height of 10 cm, the ball crumbled and required repair. This repair included running it under water for about one minute, which consequentially was revived as a smaller, yet still usable orb. After this incident, no other crumblings took place. In fact, the orb was recorded to bounce at an average height of 8 cm, which correlated with its petit dimensions. One interesting fact that should be noted is that in two out of three trials, the ball bounced away; there were 3-4 trials for each rebound test, making it a total of 6-8.

On the other hand, fellow classmates chronicled contrasting results. For example, opposing classmate’s viewed an average height of 19.3 cm. This significant difference could have been the cause of extra water being added into my ethyl alcohol due to lack of drying the water from the graduated cylinder once cleaned in between uses. However, when my lab group and I placed the polymers in the refrigerator for about 15 minutes, it yielded an average height of 14 cm. This is a substantial difference than my classmates, who reached a height of 17.3 cm. However, there is a logical variable for this difference, as well. The quantity, as well as density and exact perimeter measurements have a huge impact on the gradient in which the ball hits the flat surface and bounces back up due to its energy levels. Because my ball was more cubic than others once frozen into an even glossier ice-like structure, it produced dissimilar ramifications.

Contrasting to the Borax laundry detergent and glue polymer made on Tuesday, the silicate polymer was more condensed. And as I am addressing Tuesday’s polymer lab, keep in mind the differing variables. The first polymer lab used white Elmer’s glue (or polyvinyl acetate), water, and Borax laundry detergent. This experiment bore the culminations of a more rubbery, sticky substance that did not keep its shape well, but could be impressionable. It was indeed, more like a combination of a liquid and a solid, whereas Thursday’s polymer was a definite “snow” or “ice” crystalized formation that either kept its shape or crumbled completely. The rebound temperature test generated an effect of 7-13 cm (dropped at the same height of 30 cm) at both room-temperature and cooled at 1.7- 3.3 degrees Celsius (35-38 degrees Fahrenheit). It’s undefined variables could have ranged from being a more viscous material, to its locale in the refrigerator (cool air sinks, and it was on a medium-level shelf), or even returned body-heat from constant reconstruction. Nonetheless, these two experiments differed more that they were similar. However, one variable was reiterated in both: the shape of the polymer once it was retrieved from the refrigerator, This shape-difference could have greatly effected the end product. That, and also the fact that a polymer is always a polymer, it is formed the same way, even though it uses different catalysts each time. No matter what, this stays constant.

At this point, you may be asking yourself, “well I know that there are carbon-based polymers that are in commercial plastics. What similar properties do these two chemicals have?” And if this is in fact true, I have, or at least Google has, the answer. According to several different experts, carbon-based polymers are the products, or gifts, of nature. Fundamentally, they are organic flexible molecular structures in plastic with denoting chemical bonds. While the carbon groups are authentic, the silicon-based polymers are synthetic, or man/woman’s gift to him or herself. This too, also has a pliable chain with strong, temperature-resistant bonds, which is why it is often profit-oriented.

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