User:Dimitri Lampes/sandbox

Overview
A polymer is a substance that is composed of units of the same, repeated molecular structure, and when small glass beads, referred to as a filler, are introduced to the matrix of the polymer, that substance is known as a glass-filled polymer. The filler provides many advantages for the glass-filled polymer over a regular unfilled polymer. There can be much variation in a glass-filled polymer, such as the type of polymer used, the material that the glass beads are made of, and the size of the glass beads used. Almost any polymer can be made a glass-filled polymer, as long as a glass bead filler is added to it. Some examples of glass-filled polymers include glass-filled nylon, glass-filled polypropylene, and glass-filled polyacrylamide. A glass-filled polymer is not the same as a glass fiber reinforced polymer, which is a sheet material such as fiberglass.

Experiments Performed
In a test done to determine the effect of interfacial bonding on the toughness of glass filled polymers, it was found that as the volume percent of glass beads in the polymer increased, the toughness of the polymer also increased. The toughness of the polymer was found to be maximized when the volume percent of glass beads was between 20 and 30 percent and the surface treatment used produced poor adhesion of glass to resin in the polymer. The importance of this experiment is that it demonstrates the ideal volume ratio of the glass bead filler to the total volume of the polymer.

In an experiment testing the glass transition temperature, dynamic shear modulus, and bulk viscosity of glass filled polymers containing different materials, Phenoxy PKHH filled with glass beads and Attapulgite clay were examined. As the concentration of filler and the specific surface area of the filler increase in a polymer, the glass temperature also increases. The relative modulus for the glass filled polymer follows the Kerner equation, while the clay filled polymer shows reinforcement slightly greater. The viscosity of each of the polymers, however, does not follow any viscosity predictions for suspensions and was found to be strongly temperature dependent.

Properties
The glass beads that are used in a glass-filled polymer can be as small as 10-53 μm across, and usually make up about 10-30% of the total volume of the polymer. A glass-filled polymer will have numerous advantages over a regular polymer, such as being stronger, stiffer, and more resistant to heat due to the presence of the glass beads in the polymer. A glass-filled polymer will almost always have a higher tensile strength than an unfilled polymer, but glass-fiber reinforced polymers are often stronger than the glass-filled polymers.

The complex viscosity of the glass-filled polymer that is being examined can be determined using four parameters; the average maximum packing volume fraction, the flow activation energy, the shear thinning parameter, and an adjustable parameter. In an experiment studying the static fracture toughness behavior of glass-filled polymers using a single-edge-notched 3-point-bend test, it was found that moisture exposure increases the toughness of the polymer at the expense of poor bonding of the glass beads to the polymer. The increased toughness was a result of increased shear yielding due to the poor adhesion of the glass beads as well as an increased ductility due to the moisture exposure.

Introducing glass beads into a polymer can also have other effects on its properties. A glass bead filler can increase the dynamic elastic modulus of the polymer, as well as its mechanical damping. In a few cases, the introduction of a glass bead filler into a polymer can increase the temperature at which damping is at a maximum, as well as broaden the overall damping peak.