Name: __________________________________________________Polymer Labs/Demos

Demo - Making NylonBackground:The name “nylon” is used to represent a particular type of synthetic polymer. Different nylons can be made, and they are identified by a numbering system that indicates the number of carbon atoms in the monomer chain. Nylons made from diamines (1,6 hexanediamine) and dibasic acids (sebacoyl chloride) are designated by two numbers. As the table shows, the number 6 represents the number of carbon atoms in the diamine (1,6 hexanediamine), and the number 10 represents the number of carbon atoms in the acid (sebacoyl chloride contains 10 carbons). The nylon formed from these is called 6-10 nylon.Safety

1. 1,6 hexanediamine irritates skin, eyes, and respiratory tract.2. Sodium hydroxide is very caustic and can cause severe burns. The solid will absorb moisture

from the air and make puddles that could cause burns. Be sure to clean up any sodium hydroxide that is spilled.

3. Sebacoyl chloride irritates skin, eyes, and respiratory tract.4. Hexane is very flammable. The vapor may irritate the respiratory tract.5. Do not allow chemicals to touch skin. Wear plastic or rubber gloves during this experiment.6. Wear chemical goggles for eye protection.

Disposal1. Mix any remaining reactants thoroughly to produce nylon. The nylon should be washed

thoroughly in running tap water before being discarded in a solid waste container.2. Any remaining liquid should be neutralized with either sodium bisulfate (if basic) or sodium

bicarbonate (if acidic) and washed down the drain with water.Materials

1,6 hexanediamine. Be aware that this chemical can also be found as hexamethyldiamine or 1,6 diaminehexane.

Hexane or cyclohexane Sebacoyl chloride Plastic or rubber gloves Phenolphthalein or food color (optional)

Sodium hydroxideEquipment

Beaker, 250 mL Graduated cylinder, 100 mL Stirring rods Graduated cylinder (2), 10 mL Balance Forceps or tweezers Safety glasses/chemical goggles

Procedure1. Solution A is a mixture of 1,6 hexanediamine and sodium

hydroxide (NaOH). Phenolphthalein or food coloring may be added to solution “A.”

2. Solution B is a mixture of sebacoyl chloride and hexane.3. Slowly pour solution B down the inside of the beaker containing

solution A in such a way that two distinct layers are formed.4. With forceps or tweezers grasp the polymer film that forms at

the interface of the two solutions, and pull it carefully from the center of the beaker (see Figure 7.3).

5. Wind the polymer thread (nylon) onto a stirring rod. Wash the polymer with water before handling.

Analysis Questions

1. What is polymerization condensation?

Name: __________________________________________________

2. How did we form nylon?

3. Why is it called nylon 6-10?

Making SlimeBackground:

We are going to use polyvinyl alcohol along with Borax to make slime. The purpose of today’s lab is to determine the effect of Borax on the cross linking in slime. Are the cross-links weak or strong? Does more Borax mean better cross-linking?

Name: __________________________________________________Polyvinyl alcohol Borax Borax and Polyvinyl

alcohol=slime

Materials:

● 4% polyvinyl alcohol (PVA) solution● 4% sodium borate solution (borax)● 5 oz. cup● Wooden splint for stirring purposes● Food coloring● Plastic bag

Safety:

● The borax and the PVA will burn the eyes. Hands should be washed at the end of the lab.Procedure:

You will be assigned to one of 5 groups. Each group will be assigned one of the following “recipes”:

Team PVA Sodium borate solution (circle your groups “recipe”)

1 50 mL 1 mL

2 50 mL 2 mL

3 50 mL 4 mL

4 50 mL 6 mL

5 50 mL 10 mL

1. Add the appropriate amount of PVA to a cup…BUT DO NOT USE A GRADUATED CYLINDER--The PVA solution is sticky and you will not be able to clean out the graduated cylinder afterwards. Figure out a way to measure the required amount of PVA without putting it into a graduated cylinder….YES! THIS REQUIRES YOU TO PROBLEM SOLVE

2. Stir in food coloring if desired. (just ONE drop)3. Add sodium borate solution - stirring quickly making sure to scrape the sides and bottom

using the wooden craft stick.4. Pour entire contents of the cup into a plastic baggy and knead well.

Observations/DataTake slime out of baggy and “investigate” properties. Record these in the data table.

How does the polymer feel to touch? When rolled up like a ball, does the polymer bounce? If the putty is still in the ball shape and allowed to sit, what happens to it? Does the polymer act more like a liquid or a solid? How does it behave differently when it is stretched slowly or pulled quickly?

Name: __________________________________________________ Examine how if pours from one hand to another---see if you can “let” it pour—this

examines its flow rate…or you can hold the slime within your fingers and let it flow freely to examine its flow rate

Put your group’s observations on the board, so the class can copy it down.

SLIME BAG

OBSERVATIONS

1

2

3

4

5

Measure about 3-5 grams of slime (make sure you note the exact mass below) and leave some of it stretched out on a counter overnight. The water will evaporate and the PVA will become a dry, brittle film that is mostly transparent. Be sure to mass this film the next day.

Mass (g)Slime Day 1

Slime Day 2

Questions:

1. Find the percentage of water that was in your slime. (show your work)

2. What is cross-linking?

Name: __________________________________________________

3. Explain what accounted for the different properties of the slimes 1-5

4. Using your data chart, what is the purpose of the borax solution?

5. Which slime (#1-5) must have had the most cross-linking? ____________a. How or why did you determine that?

6. Explain what happened to the slime as it sat overnight?

Name: __________________________________________________

Shrinkidinks! (Polystyrene)Background:

The plastic used in this activity (polystyrene) is easy to work with when heated. While hot, polystyrene can be stretched into any shape required. Normally, the polymer chains in a piece of polystyrene are jumbled together in an almost random way (think of wet spaghetti noodles dumped on a plate). When heated, the strands can be stretched into a more ordered pattern and “frozen” in place. If the polystyrene is reheated, it returns to its original shape (a type of “memory polymer”.) A plastic that softens upon heating and can be reshaped is known as a thermoplastic. Thermoplastics can be melted or softened to make new products and thus are recyclable. They include polyethylene, polypropylene, polyvinyl chloride (PVC), and polystyrene (PS). Products and packaging made from one of these thermoplastics are stamped with the recycling symbol – a triangle of arrows with a number (1 – 7) inside.

Polystyrene is not the only plastic that behaves this way with heat. Soda bottles are also made from plastic with similar qualities (recyclable #1 - PETE). Soda bottles are transported as “pre-forms”. A pre-form is a rigid piece of plastic the size and shape of a large test tube. When it gets to the bottling plant, it is heated and expanded by blow molding into the desired size.

Materials:

Name: __________________________________________________ scissors rulers balance permanent markers polystyrene - PS - (recyclable #6) plastic tray covered with aluminum foil spatula toaster oven pot holder hole punch two ceramic tiles (optional)

Advance Preparation:

Collect enough items made of recyclable plastic #6 for each student to have one. Preheat the toaster oven to approximately 300° F. (Will vary from oven to oven.)

Procedure:

1. Choose a shape to make your shrinkidink. (Circle, square, rectangle, triangle, trapezoid, parallelogram)

2. Using your shape cut out the shape from your piece of polystyrene. Make sure you use rulers to make nice exact shapes…or beakers to make nice circles.

3. Measure the dimensions, calculate the area, and find the mass of your shape and record all data.

a. Shape ________________ b. Formula of the shape _______________

c. Sketch the shape with dimensions (use units)

d. Calculate the Area (show your work)

e. Mass of Shape _________________4. Shrink each shape using the preheated toaster oven (300oC). Place the piece of

polystyrene on an aluminum foil covered tray and place it in the oven. It should take about a minute. It will sometimes curl up as it heats…let it be…usually it uncurls if you leave it alone. Once it has uncurled, it can be removed from the oven.

Name: __________________________________________________a. Watch it carefully. Sometimes it will curl up and “stick” to itself. You can

usually “undo” it by manipulating it with forks if it doesn’t harden too quickly. Use the spatula to flatten it while it is still hot if still slightly curled. Pressing the piece between two ceramic tiles works very well.

5. Measure the dimensions, calculate the area, and measure the mass of your geometric shapes again.

a. Sketch the shape with dimensions (use units) b. Calculate the Area (show your work)

c. Mass of Shape _________________6. Calculate the percent reduction of plastic area. Show your work.

EX: Let’s say gas prices are $3.20/gallon last summer. This summer gas prices rise to $3.90/gallon. The percent increase would be calculated as follows.Change in price → 3.90-3.20= 0.70 Change in price / the original price x 100 = % increase → 0.70/3.20 x 100 = 21.9% increase

Polyurethane Resin Cast Members of the Polymer Family

Polymers can be separated into two different groups depending on their behavior when heated. Polymers with linear molecules are likely to be thermoplastic. These are substances that soften upon heating and can be remolded and recycled. They can be semi-crystalline or amorphous. The other group of polymers is known as thermosets. These are substances that do not soften under heat and pressure and cannot be recycled or remodeled. They must be re-machined, used as fillers, or incinerated to remove them from the environment.

ThermoplasticsThermoplastics are generally carbon containing polymers synthesized by addition or condensation polymerization. This process forms strong covalent bonds within the chains and weaker secondary bonds between the chains. Usually, these secondary forces can be easily overcome by thermal energy, making thermoplastics moldable at high temperatures. Thermoplastics will also retain their newly reformed shape after cooling. A few common applications of thermoplastics include: parts for common household appliances, bottles, cable insulators, tape, blender and mixer bowls, medical syringes, mugs, textiles, packaging, and insulation.

ThermosetsThermosets have the same weak bonds that thermoplastics do. However, they have a stronger linkage to other chains. Strong covalent bonds chemically hold different chains together in a thermoset material. The chains may be directly bonded to each other or be bonded through other molecules. This “cross-linking” between the chains allows the material to resist softening upon heating. Thus, thermosets must be machined into a new shape if they are to be reused or they can serve as powdered fillers. Although thermosets are difficult to reform, they have many distinct advantages in engineering design applications including:

1. High thermal stability and insulating properties2. High rigidity and dimensional stability3. Resistance to creep and deformation under load4. Light-weight

A few common applications for thermosets include epoxies (glue), automobile body parts, adhesives for plywood and particle board, and as a matrix for composites in boat hulls and tanks.

Procedure:

Name: __________________________________________________1. Measure out 2 fluid ounces of Part A and 2 fluid ounces of Part B into separate cups. (Or 18

drams of each to make sure the mold is filled.) PER 4 PEOPLE!!!!2. Add several drops of dye to each cup- Decide on this as a GROUP! 3. Pour both parts into a larger cup and stir for 30 seconds. 4. Fill molds to edge but do not let run over. 5. Let sit for 10 minutes or until cool enough to handle and remove from mold.6. Rough edges may be sanded, filed, or trimmed with a razor blade.

Analysis Questions

1.

Name: __________________________________________________

Latex BallBackground:English chemist, Joseph Priestly, who discovered in 1770 that the material could rub out pencil marks and thus the name rubber was coined. Originally the rubber tree was known only in the Amazon Valley of Brazil, but an amateur British botanist introduced seeds of the tree to Malaysian plantations in the late 1870's. In total there are about 18,000 species of latex-producing plants, but only a few species are actually being used. Today over 85% of all natural rubber comes from the Far East and over 99% of all the world's natural rubber supply comes from a single species and it is known as the rubber tree (Hevea brasiliensis ).

The consistency of latex is around 35% pure rubber, over 60% water, with the remainder being proteins. Prior to 1839 rubber products were not widely used because it was hard to process. Latex needed to be processed within hours of obtaining it from the tree as, once the rubber congealed, there was no means to return it to the liquid state. In addition, it became sticky in hot weather and stiff in cold weather. However Charles Goodyear changed that with an accidental discovery. By

Name: __________________________________________________spilling a sulfur-rubber mixture on a hot stove, the compound was "cured" as a result of the heat. The process was called vulcanization in honor of Vulcan, the god of fire.

Vulcanized rubber is a natural elastomer that has been made more durable by a biochemical process that cures the rubber. During vulcanization, the milky latex from a rubber tree is combined with a curing ingredient — usually sulfur — and heated under pressure. This process makes the rubber more stable, tougher and more resistant to heat, which made it more useful for industrial purposes and ideal for certain products.

Vulcanization chemically combines the rubber and sulfur. At high pressure and high temperatures, the sulfur atoms form links or bridges between long chains of the rubber molecules. This increases the rubber's strength and durability and reduces its stickiness. It also makes the rubber retain its elasticity at a much wider range of temperatures, making vulcanized rubber more useful for many purposes.

Before vulcanization was discovered, natural rubber could be coagulated with acid and made malleable so that it could be shaped and formed. At high temperatures, though, the rubber would become sticky or melt. At low temperatures, the rubber would become brittle. These qualities made this type of rubber impractical to use in industrial settings.

Historically, the relationship between the bounce of a ball and temperature is legendary. In its infancy professional baseball managers would alter the bounce effect of baseballs by either freezing them or placing them in the oven several hours before the visiting team arrived. Depending upon which team had the greater amount of home-run hitters, the manager would either heat or freeze the baseballs to give his team a decided advantage.Safety:

Wear safety goggles and lab apron.Procedure:

1. Measure 15 mL of latex into a paper cup. (Do not pour latex into a graduated cylinder.)2. Feel texture of latex. Immediately wash your hands.3. Add 15 mL of water to cup. Stir.4. Add 15 mL of vinegar to the cup while stirring.5. Place the polymer lump under running water.2. Gently pull the lump of rubber from the stick. Squeeze the lump into a ball while under water.

Squeeze the ball several times to remove unused or trapped chemical.3. Squeeze the ball dry in paper towels.4. Record observations.

Analysis Questions

1. What is the natural polymer that we are using in the lab?

2. What is the latex ball considered after we add the vinegar and water? Why?

3. If the managers for the Cubs wanted to cheat, would they want to heat the baseballs up or freeze them? Why?

Name: __________________________________________________4. Define vulcanization.

5. How did vulcanization change the rubber industry?

Demo – Packing PeanutsIntroduction:

Explain the teacher’s “magic trick”?

Observations:

Describe packing peanut A. Describe packing peanut B.

Describe what happens when we:

Place Peanut A in Beaker A

Place Peanut B in Beaker B

Place Peanut A in Beaker B

Name: __________________________________________________

Place Peanut B in Beaker A

Analysis Questions (after polarity notes):

1. What type of packing peanut is best? Explain.

2. Why would it be a bad idea to carry gasoline in a Styrofoam cup?

Demo - Sodium Polyacrylate vs. High Density PolyethyleneQuestion: How much water can the diaper hold?

How do you THINK this is possible?

Define.

Hydrophobic: Hydrophilic:

Compare the two powders. Write your observations below.

Sodium Polyacrylate High Density PolyethyleneObservations of the powders.

What happens when you drip droplets of water onto the powders?

Hydrophobic or Hydrophilic?

Analysis Questions

Name: __________________________________________________1. What can a hydrophobic polymer be used for? List at least two uses.

2. What can a hydrophilic polymer be used for? List at least two uses.

Demo – Fortune Fish

What is it made of? Fortune Telling Fish are made of a super-thin material called cellophane.

How does it work? Cellophane is a hygroscopic material. “Hygro” means water, and “scopic” means to find, making cellophane is a “water-finding” material. This water-finding property means that the cellophane fish seeks out and absorbs the moisture from the surface of your palms. Since the palms of human hands have a lot of sweat glands, the cellophane is immediately successful in finding moisture to absorb.

When the absorption begins, the Fortune Telling Fish begins to swell and the hand-facing surfaces of the fish will start to curl up and away from your palm. The wriggling effect comes from the light-weight nature of cellophane that makes it very susceptible to even the slightest of air currents.

Are the fish hydrophobic or hydrophilic? Explain.

Name: __________________________________________________

Name: __________________________________________________

Comparing Rigid and Flexible Urethane FoamPurpose: To gain an understanding of the preparation and properties of two types of Urethane Foam

Background: It is hard to go a day without coming across some sort of polymer foam. Polymer foams are found virtually everywhere in our modern world and are used in a wide variety of applications such as disposable packaging of fast-food, the cushioning of your furniture and insulation material.

Polymer foams are made up of a solid and gas phase mixed together to form foam. This generally happens by combining the two phases too fast for the system to respond in a smooth fashion. The resulting foam has a polymer matrix with either air bubbles or air tunnels incorporated in it, which is known as either closed-cell or open-cell structure.

Closed-cell foams are generally more rigid, while open-cell foams are usually flexible.

Polymer foams can be divided into either thermoplastics or thermosets, which are further divided into rigid or flexible foams. The thermoplastics can usually be broken down and recycled, while thermosets are harder to recycle because they are usually heavily cross-linked. Polyurethanes are mostly thermosets.

Issues facing the polymer foam industry are that of waste disposal, recyclability, flammability and the effect of blowing agents on the environment. The restrictions on the use of CFC’s (chloro-fluoro-carbons) have become very important in making polymer foams more environmentally friendly. Advances in biodegradable foam materials are also helping to improve the recyclability and waste disposal.

The reason polymer foams are so widely used is that they have a lot of advantageous properties. The density is low, and so the weight reduction compared to other options is significant. Some polymer foams have very low heat transfer, making them optimal insulators. Many are flexible and soft, meaning they provide more comfort when used for furniture and bedding.

Polymer foams were first made in the 1930's and -40's, with foamed polystyrene being the first polymer foam in 1931. Dr. Otto Bayer at the start of World War II invented polyurethane. It was first used as a replacement for rubber and also used as a coating to protect other common materials at the time such as metals and wood.

A few years after the war, the flexible polyurethane foam was invented and it was first then that it started being used for cushioning in furniture and automotive industry.

Polyurethanes can exist as both rigid and flexible foams, and as a coating or adhesive material. Since polyurethanes come in so many forms and can have a wide variety of properties, it is also used in many different applications. Rigid polyurethanes are used as insulation and flotation, while flexible ones are used for cushioning and packaging. In addition, they are used as adhesives in construction and transportation. Rhinoskin is an example of polyurethane used for coating and protection. It is sprayed onto a surface and then sets to protect the underlying layer.

Rigid polyurethane foams are mostly used in thermal insulation applications such as refrigerators, freezers, insulated buildings, insulated trucks carrying produce, water heaters, thermoses etc. Hence, rigid polyurethanes contribute a lot to energy saving appliances. Polyurethane foams with a high

Name: __________________________________________________closed-cell structure are moisture resistant and can be used as buoyancy in boats. The advantage is that the foam will not deflate upon a puncture, but retains its buoyancy even after many load-unload cycles.

Most of the flexible polyurethane foam produced is made for cushioning. This includes furniture, packaging and transportation. Furnishings use polyurethane foam for carpet underlay, bedding, home furniture. The transportation industry uses it in seating cushions for the airlines, trains and bicycles and cars. It is also used in a wide range of other applications for cars such as sound insulation and vibration dampening. Other applications include clothing, toys, electronics and other applications for protection or cushioning issues.

When the 2 liquids below are mixed together they cause a chemical reaction that generates heat and carbon dioxide. The carbon dioxide gas is what forms the bubbles in the polymer matrix to create the foam.

Part 1 – Preparing Rigid Urethane FoamMaterials – Rigid Urethane Foam

o Molding Foam (Urethane) – “Blue” – Parts A and Bo Small Paper Cups (2)o Craft Sticko Balance

Procedures:

1. Set balance to read zero when paper cup is placed on it.2. Measure out 10 grams of Part A into cup and set this aside.3. Place a second paper cup on the balance and set balance to read zero.4. Place 10 grams of Part B into cup.5. Mix Part A into Part B – total mixing time should be about 30 seconds.6. Let the mixture sit and allow foam to form.

Part 2 – Preparing Flexible Urethane FoamMaterials – Flexible Urethane Foam

o Flexible Urethane Foam – “Pink” – Parts A and Bo Small Paper Cups (2)o Craft Sticko Balance

Procedures:

5. Set balance to read zero when paper cup is placed on it.6. Measure out 5 grams of Part A into cup and set this aside7. Place a second paper cup on the balance and set balance to read zero.8. Place 15 grams of Part B into cup.9. Mix Part A into Part B – total mixing time should be about 30 seconds.10. Let the mixture sit and allow foam to form.

Observation / Analysis Questions:

Part 1 – Rigid Foam Part 2 – Flexible Foam

Name: __________________________________________________Record observations after about 3 minutes. What does it look like? Feel like? Smell like?

How has the mixture changed? Describe the characteristics of the material that was made, before and after the reaction.

What applications do you see this product being used for? For example, do you think it’s an insulator or a conductor?

Final Analysis:

1. Compare and contrast the two types of Urethane foam. Use information from the article as well!

a. How are they similar?

b. How are they different?