lab 4 - initiator is a chemical compound that helps start a...

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Experiment 4 Lab Report and Questions 1. Because the initiation is the slow step, the rate of polymerization depends mostly on it. If the experimenter only wishes to achieve long polymer chains and does not care about the rate of producing them, he would want to use low concentrations of initiator because reducing the concentration of initiators results in longer polymer chain lengths. This happens because the fewer the initiator radical, the fewer the initial polymer chains there will be to grow on, thus making the monomers have to grow on the few existing initial polymer chains, and therefore, the longer the polymer chains. 2. The polymer is thermoplastic because it is first melted and then re-formed into some other shape. 3. A chemical catalyst is a substance that increases the rate at which a chemical reaction occurs; however, the catalyst itself does not undergo chemical change. An
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Unformatted text preview: initiator is a chemical compound that helps start a chemical reaction, such as polymerization. But unlike a catalyst, an initiator is consumed in the reaction. Benzoyl peroxide is an initiator and not a catalyst because it becomes part of the polymer and is consumed in the polymerization reaction. 4. Polymer A and Polymer B are both very viscous solutions, but Polymer B is more viscous than A. This is because Polymer B is the cross-linked polymer and Polymer A is the linear polymer. Polymer B has more polar groups (the oxygen atoms) that increase the dipole dipole interaction between molecules than Polymer A. 5. 6. 7. The gel is soft. It stretches a bit but can be poured or torn easily. It breaks into pieces when I pulled with little force. The gel is very similar to Slime. 8. Slowly, the gel would take the shape of the watchglass....
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This note was uploaded on 04/07/2012 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at Berkeley.

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lab 4 - initiator is a chemical compound that helps start a...

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