Wednesday, March 9, 2011

Polymer Lab Group Investigation

Table 6: Haley C., Keara B., Holden L.

Title: Tacky Glue Polymer

Problem: How does the tacky glue change the physical and chemical properties of the polymer?

Hypothesis: When the white Elmers glue (polyvinyl acetate) is replaced with tacky glue, the end result of a polymer will ultimately be stretchier.

Background Info: Tacky glue is just a "white glue" that's made especially thick so that it will grab and hold onto things more rapidly than thinner white school glues (such as Elmer’s glue). Also a terminology for glue that has not dried, but does so after attached to the substances being held together in a clear and flexible manner. This, as well as other PVA glues (polyvinyl acetate) must be kept from freezing in a cold environment, otherwise it will not act according to original plan. Slight to obvious discoloration of items is one symptom of tacky glue gone bad, and will peel of of glass, metal, and plastic after dehydrated. It is not a standard request for archival items due to its pH neutral chemical property. Nonetheless, if a quick clean up is in order, soap and water will work perfectly. This type of glue is typically available at craft stores, hobby stores, fabric stores, or even at places such as Target, etc.

Materials: 1 Tacky glue - polyvinyl acetate
1 plastic spoon
1 200 or 250 mL beaker (Pyrex)
1 500 mL beaker (Pyrex)
1 plastic or glass stirring rod with bent tip
1 graduated cylinder
525 mL of water
2 tsp of Borax laundry detergent (hydrated sodium borate)
1 ruler (30 cm)
1 plastic bowl (or any bowl that can hold a decent amount of material)
1 square of paper towels (or any absorbing material used for cleaning)
1 refrigerator (with an average temperature of 1.7- 3.3 degrees Celsius)
1 flat surface (a table will do)

1. Arrange the materials to be used at the head or front of a flat surface.
2. Add 400mL of water to the larger beaker. Set the used beaker aside.
3. Pour about ½ cup of Borax into the plastic bowl.
4. Stir in two teaspoons of borax into the water bowl for about 30-60 seconds or until the solute has dissolved in the solvent. Set this aside for future applications.
5. Measure 40 mL of tacky glue and transfer it into the smaller beaker. Fasten the cap back on the glue when not pouring.
6. Add 5 mL of water, measuring with the graduated cylinder, to the adhesive.
7. Record any observations of physical or chemical properties.
8. Quickly sanitize and rid the stirring rod of any previous substances.
9. Give the Borax compound a brisk stir.
10. Blend the glue and water for about 30-60 seconds, or until fully integrated.
11. Record any observations of physical or chemical properties.
12. Calculate 25 mL of the Borax solution that was just stirred with the graduated cylinder.
13. Deposit the solvent matter into the small beaker.
14. Coalesce the two elements, both solvent and solute, with the stirring rod.
15. Examine its features and document the discovery, just before cleaning the materials.

Stretchy Test Procedures: One ruler and a flat surface (preferably a level table) is needed to perform this experiment. After the polymer has successfully been formed, and is set to a comfortable, pliable room temperature, the trial(s) may commence. Align the ruler with the edge of the table; have the side with the centimeters facing the edge. Mold the sticky substance into an oval shape. Firmly grasp the polymer with both hands, leaving about one to two centimeters of material between fists. Stretch the matter at a controlled pace so to be sure that observations are able to be recorded, as well as allowing the polymer to adjust to the change in physical properties. How do you know when to stop stretching? When the link between the two wedges disperse in thin filaments, or the bridge suddenly splits, then it is a definite sign to halt the operation and record significant data. Depending on the fiber being tested, another ruler may need to be added to the materials in order to document accurate measurements. However, this is just in case the polymer spreads wider than originally expected (30 cm). Also, this test will need to be reiterated two to three more times in order to regulate an average calculation of its break-point. Compare and contrast with previous test results, as well as separate experiments.

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.

How does it work?
A polymer is a long chain of molecules.

If the long molecules slide past each other easily, then the substance acts like a liquid because the molecules flow. If the molecules stick together at a few places along the strand, then the substance behaves like a rubbery solid called an elastomer.

Borax is the compound that is responsible for hooking the glue’s molecules together to form the putty-like material.

Results and Conclusion of Tacky Glue Lab: Tacky glue is known for its thicker, hydrated attributes. These qualities are visible to the naked eye when the top of the glue bottle is unlatched and the substance is poured out in a slow manner. Once the 5 mL of water is added to the glue, it seems to settle down on the surface. This is a repeat of the previous polymer test with white Elmer’s glue. However, the difference soon becomes apparent when the stirring rod is put into use and the chemical properties of the tacky glue activate with the Borax and water solution, acting as a catalyst for the soon-to-be-established polymer. Approximately 30-60 seconds of effortless stirring brings about a visual of altered adhesive clinging to the side of the container and an easily cleaned stirring rod. This extremely contrasts with the opposite experiment where the paste stuck to just about everything it came in contact with, such as glass, metal, skin, and paper. The tacky glue polymer was actually “picky” when choosing what materials to cling to, which included skin, paper towels (because of their texture), and itself. When it originally emerged from the beaker, it had bubbles attached to its exterior. This could possibly be due to the Borax mixing with water, a solvent mixing with a solute, thus creating bubbles from its soapy features. Because tacky glue is hydrated, it left the experimenters with a leaking solid that emanated glue. This excess substance was disregarded and was left in the glue’s original container, which had a large remainder to foggy liquid that did not set in with the polymer at the beginning. Yet another observation that was recorded was that the polymer slid smoothly off of the stirring stick, in variance with the Elmer’s glue lab, which roughly was torn off of the stick. It’s physical features when moist include a lumpy, slimy, waterproof-like, and somewhat less adherent texture. When dried, it gives the polymer a chance to express its capabilities to become more compact and depict a more solid image. Nonetheless, when stretched, the tacky glue substance appeared to have a central fiber, surrounded by sludge made from saturated glue and Borax, and was not a success in the Stretching Test, reaching a maximum limit of 23 cm in length. Once it was permitted to resolve on a balanced surface for about 5-10 minutes, it stretched to a total of 18 cm. Also, the rebound factor was determined at a height of 8-11 cm. The opposing polymer yielded results of 7-13 cm in height. This small difference could possibly be the aftermath of two polymers made out of the same form of PVA glues (polyvinyl acetate), where one is hydrated (tacky glue) and the other is not. After spending approximately 10-15 minutes in a 1.7 to 3.3 C degree refrigerator, the consequences (physical and chemical property change) were outstanding. When stretched slowly, it reached a height of 12 cm. However, this was not what excited us. The fact that we needed two rulers to measure the length of the stretched out polymer, which measured an average of 50 cm and reached a maximum of 59 cm) was incredible. It is important to make note that to reach such dimensions required equal tug force from both ends, as well as a leisurely speed in which to keep constant. This suggests that not only is the tacky hydrated glue stretchier, but also works better when left to dry, whilst Elmer’s glue (a much thinner adhesive) is more pliable when wet. Any variable that might have effected this experiment in particular may have involved the surface that it was bounced on (for the Rebound Test), the distance away from the ruler in which it was held (Stretch Test), and the overall amount of added hydration (from the tacky glue) to the solution. In conclusion, we can draw this results section to a close with a disproved, earlier stated hypothesis and that the thinner the polyvinyl acetate glue, the more flexible it is.

Results of Elmer’s Glue Lab: (Enclosed is the results of the Elmer’s Glue lab to be compared by the viewer. Previously stated comparisons are available to be read in the Results and Conclusion of Tacky Glue Lab section.) In order to document thorough results, it was vital to record the physical and chemical properties and reactions that occurred throughout the experiment. The first, and estimated to be seemingly one of the simplest, observations of the lab regards the minute details when stirring the solute (solid, in this case, the borax for the most part) into the solvent (liquid, in the case, the H2O and Borax solution for the most part). If the mixture is not blended, and a substantial wedge of borax laundry detergent is neglected at the bottom of the beaker, results may not be produced as they had been anticipated. This may be a consequential variable when dealing with later issues, such as skimming out 25 mL of the separated solute to commencing the chemical reaction of monomers linking to form the whole polymer. For best results, the two components of the mixture needs to be properly blended for 1-2 minutes of stirring, then again for about 30-60 seconds just moments previous to being added to the glue. After the proper quantity of stirring takes place, the solution will be saturated, not concentrated or diluted. If the solution is concentrated, then the borax would have to outweigh the amount of H2O in the beaker, and thus prevent the catalyzing proportions to coexist with the sticky adhesive in the alternative, yet smaller beaker. Nonetheless, a diluted solution would not culminate the correct response, either. An erroneous ratio of solid to liquid (solute to solvent) would severely modify the outcome of the experiment, because the end polymer would consist of too much liquid to hold any shape at all. On another note, the glue requires a bit of attention. Because it is in the glue’s nature to be viscous, it needs to be dually noted that its entails an opposite reactor (a solvent, in this case, the Borax solvent) to accurately activate the monomers, and ultimately form the long chain of of molecules in order to create the anatomy of a polymer. The following answers the “why” question in the situation. When the 5 mL of unembellished H2O is added to the resin, it just settles on the top as some sort of liquid film. And when the embellished water is annexed in the mix, with the help of the stirring rod, the reaction is catalyzed due to its chemical properties. The apparent physical attributes of the glue is altered into a swelled, glutinous adhesive with less viscosity than its genesis. In addition to this vital information, there are several other reactions that are significant enough to be mentioned. The glue fundamentally renders the following characteristics: coherent (as illustrated on the stirring rod due to its horizontal position and gravitational pull), slimy, mucilaginous, ill-fitted for reshaping, has similar qualities to liquified rubber with elasticity, and ultimately animated (with a vibrating reverberation) on contact. Any other qualities that remain while exposed to body heat via finger tips and palms include: H2O-infused, flexibility, and corpulent. The average rebound test yielded results of an average height of 7-13 cm. This evaluation was a good arbitrator when establishing the polymer’s physical and chemical properties due to its unbiased standpoint. To illustrate my point, visualize a room-temperature environment with a limited amount of variables in the atmosphere; it is the perfect locale for a controlled experiment such as this one, with no breeze or being to disturb it. After 10-15 of chilling in the refrigerator, the test was repeated about 3-4 more times with the same average height of 7-13 cm. However, this set of trials bore contrasting ramifications. Unlike the previous ball of water, glue, and Borax laundry detergent, this new gelatin-like sphere had a glossy off-white hue to it and held a shape about half the time that the original had been capable of. After the third trial with this new form, the body heat warmed the orb, and consequentially produced results with frequent similarities to the pioneering polymer.

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