Title of Experiment: Synthesis of the Plexiglass Polymer

Name: Katie Sours

CHEM 321L Section: TUES PM

Date: 8/31/2015

Title of Experiment:Synthesis of the Plexiglass Polymer

Source Reference:Linfield College Chemistry, CHEM321, Course Webpage. (accessed Aug 31, 2015).

Introduction:The objective of this experiment was to learn basic laboratory techniques for measuring and mixing reagents, controlling reaction temperature, and cleaning a product free of excess reagents. This goal was met by synthesizing a polymer, poly(methyl methacrylate), from its monomer unit, methyl methacrylate (Figure 1). This experiment provided opportunities to practice basic laboratory techniques that will be utilized throughout the entire course.

CHEM 321L Minor Laboratory Report Form Fall 2015

Figure 1: The structure of methyl methacrylate, the monomer unit utilized to form the Plexiglass polymer by way of its alkene functional group (circled above).

Experimental Methods:Benzoyl peroxide (0.12 g, 5.0 x 10-4mol) was mixed with enough methyl methacrylate to fill a small test tube just over half full (approximately 2.5 mL, 0.023mol). Calculations for mole amounts used can be seen in the Appendix. After inverting the reaction container (while stoppered) to mix its contents, the mixture, loosely stoppered with a cork, was then heated in a water bath (X°C) until it started to appear viscous (approximately X min). At this point, a paperclip was embedded in the reaction mixture, which was left in the water bath until solidified (an additional X min). Once cool, the polymer product was freed from its container by carefully breaking the test tube.

Results:The experimental polymer product (shown in Figure 2) was a solid substance with some bubbles embedded in it, and a hazy yet transparent color.

CHEM 321L Minor Laboratory Report Form Fall 2015

Figure 2: The experimental polymer product, plexiglass (insert a photo of product).

Discussion:The objective of this experiment was to learn basic laboratory techniques and functional groups by way of synthesizing poly(methyl methacrylate) from its monomer, methyl methacrylate. Techniques included measuring and mixing reagents, controlling reaction temperature through use of a water bath, and cleaning a final product. Qualitative evidence gathered supports two conclusions: First, the final product appeared to be different from the starting reagents, as the product was a milky-transparent solid with some bubbles, and the reactants were a colorless, clear liquid and a white solid. Second, the product’s appearance during heating (viscous and transparent) was similar to the published description of poly(methyl methacrylate): amorphous and transparent1.Together, these observations indicate that (1) a reaction actually took place and (2) it was likely the desired addition polymerization reaction, transforming the alkene functional group of the monomer unit into the desired polymer chain. Overall, the experimental evidence indicates that the basic laboratory techniques were learned properly and thus the objectives of the experiment were met.

References:

Sigma Aldrich Webpage. (accessed Aug 31, 2015).

Appendix:

Calculations for determining moles of reagents used:

0.12 g benzoyl peroxide used x 1 mol benzoyl peroxide = 0.0004954 = 5.0 x 10-4 mol benzoyl peroxide

242.23 g benzoyl peroxide

2.5 mL methyl methacrylate used x 0.936 g methyl methacrylate x 1 mol methyl methacrylate = 0.023 mol

1 mL methyl methacrylate 100.12 g methyl methacrylate methyl

methacrylate

CHEM 321L Minor Laboratory Report Form Fall 2015