Five

Formation of Polyurethane Foam
 * //MICHAEL//, __ANTHONY__, AND //STEVEN'S// __PAGE__**


 * **Chemicals:** ||
 * Desmodur (diisocyanate) ||
 * Desmophen (polyhydroxyester) ||


 * **Glass wares:** ||
 * beaker 600 mL ||
 * 2 beakers 100 mL ||
 * glass stirring rod ||


 * Experimental procedure:**

60 mL Desmodur (diisocyanate) and Desmophen (polyhydroxyester) are poured simultaneously into a beaker. The mixture needs to be stirred thoroughly for approximately two minutes with a glass stirring rod.

MATERIALS Polyester Polyol (Part A) from Industrial Arts Polyfunctional Isocyanate (Part B) from Industrial Arts Stirring Rods Plastic Cups Food Coloring Tablecloth Gloves Paper towels PROCEDURE (1) Remember that polyurethane is flammable and should not be brought near an flame. (2) Wear gloves when handling the chemicals. (3) Place approximately 20mL of each chemical, the polyester polyol and polyfunctional isocyanate, into a large cup. (4) Observe the viscosity and volumes of each chemical. Record your observations. (5) Add food coloring to create colored foam. (6) With a stirring rod, mix the contents thoroughly. (7) Feel the cup for temperature change. Record your observation. (8) When the foam begins to expand, stop stirring. (9) Observe the color, texture, temperature and volume of the foam once the reaction stops. Record your observations.


 * Result:**

A foam is formed, which will expand to about thirty times its original liquid volume. The beaker will actually get warm - this indicates an exothermic reaction.


 * Discussion:**
 * Discussion:**

Polyurethane is formed by a polyaddition of diisocyanates and diols. The alcohol component is a polyhydroxyester (**1**) containing a blowing agent. The diisocyanate component is low molecular.

The blowing agent is solved in the liquid. As the foam hardens the gas is trapped in the cells and small bubbles will be formed throughout the polyurethane product. The finished material is therefore a rigid foam.



The blowing agent is solved in the liquid. As the foam hardens the gas is trapped in the cells and small bubbles will be formed throughout the polyurethane product. The finished material is therefore a rigid foam.


 * HANDLING POLYURETHANE FOAM SAFELY**

petroleum. It is highly flammable.
 * ∑** Polyurethane foam is a by- product of the same process that is used to make

open flames and sparks.
 * ∑** Polyurethane foam ignites easily and burns rapidly. It should be kept away

fumes.
 * ∑** When it burns, polyurethane releases a great amount of heat and toxic


 * ∑** Burning polyurethane can cause suffocation in a poorly ventilated area.

gloves.
 * ∑** Polyfunctional isocyanate and polyester polyol should be handled with

flame retardant additives that can be toxic if ingested. Whether or not the foam you are working with contains them, it should not be ingested or even placed in the mouth. (JUST LIKE ANY OTHER CHEMICAL!)
 * ∑** DO NOT INGEST THE POLYURETHANE FOAM – some foams have

1) Describe the type of experiment/demonstration your group will be researching and conducting. 2) You may add text, images and information you plan to add to **__your group's__** presentation. 3) There is also a "Discussion" area where you might send messages to each other and reply. Please keep this information related to your topic. 4) Each day we are in the lab, you are REQUIRED to make a "comment" in the Discussion Area telling YOUR FIRST NAME and exactly what you did on your project FOR THAT DAY, what information (in general) you added to your group's wiki or how you contributed to the group's project. THIS IS HOW YOU WILL RECEIVE DAILY PARTICIPATION POINTS when we are working in the computer lab. IF YOU DO NOT ADD A COMMENT WITH YOUR NAME, you will not receive your daily points. 5) You may let me know confidentially if ANYONE in your group is not doing their fair share. I WILL NOT share this with anyone. I will check to see what that person is actually doing and may take away points or put that person in a group by themselves if I think is it necessary