The purpose of this experiment is to use FTIR spectroscopy to compare and identify different popular brands of plastic wraps. You will be given a sample of one of these wraps (Sam's Choice Wrap, Kroger Plastic Wrap, Glad™ Wrap, Reynolds Plastic Wrap, and Saran™ Wrap).Most plastic wraps are made of polyethylene, however some are made of other polymers (see table below), and most have additives to enhance their strength, add color, etc. Use the table below and draw the structure of one monomer of each. What are 3-4 peaks you expect to see for each wrap regardless of which polymer it is made? What feature does each of the three kinds of polymers listed have that you expect would produce a peak that would enable you to identify it specifically?
Procedure:
Cut a small piece of the plastic wrap and tape it across the sample holder in the FTIR. Run a scan and then use the Omnic library and determine the identity of the sample.
Results and Discussion:
Summarize the types of bonds present in your sample. Decide which kind of polymer makes up your plastic wrap. Relate the different groups in the molecule to the different peaks seen.Obtain a copy of the spectra for the other samples tested and do the same thing.
What peaks do all of the IR spectra have in common? What peak(s) are found only in one or two of the samples and can be used as distinguishing peaks? Which plastic wraps are made of the same polymer?
Polymers that make up Common Brand-Name Plastic Wraps
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Kroger Plastic Wrap
Glad™ Wrappolyethylene (PE) (ethene monomer) Reynolds Plastic Wrap polyvinyl chloride (PVC) vinyl chloride
(chloroethene monomer)Saran™ Wrap copolymer of vinyl chloride and vinylidene chloride
(1,1-dichloroethene) monomers