Polymer Science Investigations
Submitted to: Yunhua Li (GTA)
CHEM 1045 (82045), Experiment 7, 11/02/16
Honor Code Signature:
Abstract.
The objectives of the experiment include, understanding basic polymer classifications, using
rheology and the density of specific substances to find the weight, composition, and topology of
polymers, and to modify a protein to examine a biopolymer. To accomplish these objectives, we diluted
pellets and observed buoyancy, mixed chemicals and interacted with a UV light to test a biopolymer,
conducted titrations, used rheology to determine molecular weight, measured the viscosity of the
molecular solutions, and tested the topology of a polymer through the formation and addition of heat to it,
and then the examination of the solubility of the polymer. The results showed which pellets were PP and
PVC, and therefore sank in water, and which were HDPE, LDPE, and PP, and only sank with the addition
of ethanol. The lowest density was the polypropylene with a calculated density of 0.87 g/cm3. The
relationship between a higher viscosity resulting in a higher concentration, was also found. The lower
concentration was discovered to have a much faster time of travel (average of .92s) between two arbitrary
marks than the higher concentration (average of 4.92s).
I. Introduction.
A Polymer is defined as a chemical compound that is made of small molecules that are arranged
in a simple repeating structure to form a larger molecule. They have become incredibly important in every
aspect of our human lives. We may not be aware, but we use and consume polymers every day. All the
way from playing an integral role production of cars and tires, of light-weight electronic devices, and
most any commercial product. The fundamental polymer parameters in this experiment consist of
chemical composition, molecular weight and molecular weight distribution, morphology, topology,
rheology, and surface features and polymer additives.
Step-growth and chain-growth polymerization are the two main synthetic methods. Both methods
require a monomer, which polymerizes into the polymer. The chemical composition of the monomer is
then tested afterward to determine the final chemical composition of the polymer.
The molecular weight of polymers depends on the number of chain links combined during the
polymerization process. No polymer has a specific molecular weight because the range of possible
molecular weights is huge and there are too many factors that determine the polymer’s size.
Rheology is the branch of science that studies the flow and deformation of matter. Therefore, one
can see how examining viscosity in the experiment is relatable. As the