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MCET210
Midterm
| Term | Definition |
|---|---|
| Initiation, Propagation, and Termination | The three steps addition polymerization |
| Ethylene | X = H |
| Propylene | X = CH3 |
| Vinyl Chloride | X = Cl |
| Styrene | X = Octagon |
| (Σ Ni * Mi) / Σ Ni | Formula for Number Average Molecular Weight |
| ∑(Ni Mi^2) / ∑(Ni Mi) | Formula for Weight Average Molecular Weight |
| Ni | Number of Molecules |
| Mi | Molecular Weight |
| Mn | Number Average Molecular Weight |
| Mw | Weight Average Molecular Weight |
| Narrow Molecular Weight Distribution | Most polymer chains are similar in size; a small range of difference in weight |
| Broad Molecular Weight Distribution | There is a significant range of difference in weight between polymer chains |
| Mn/Mi | Formula for Degree of Polymerization |
| Thermoplastic | Can be melted, and reformed, and melted again. Created by addition and condensation reactions. |
| Thermoset | Can be molted, but once melted, it cannot go back. Created only by condensation reactions. |
| Free Radical Catalyst | This kind of catalyst has a broad molecular weight distribution, and is easier and cheaper to process. |
| Coordination Catalyst | This kind of catalyst has a narrow molecular weight distribution, is more difficult to process, but has more consistent properties. |
| Condensation Polymerization | A chemical reaction in which molecules combine to form water, and condenses out a simple substance. |
| Properties, Environmental Safety, and Chain Length | The impacts of byproducts on the condensation reaction |
| Increased Conductivity, Swelling/Shrinkage, Increased Ductility | The impacts of moisture on polymer properties. |
| Oligomer Stage | The first stage of thermoset polymerization |
| Gelation Stage | The second stage of thermoset polymerization |
| Crosslinking Stage | The final part of thermoset polymerization |
| Semi-Crystalline Polymer | This polymer has a higher density than its counterpart, resulting in lower free volume, and lower specific volume |
| Amorphous Polymer | This polymer has a lower density than its counterpart, resulting in higher free volume, and higher specific volume |
| Higher Crystallinity | These kinds of polymers have a higher tensile strength, higher thermal stability, and a distinct melting temperature |
| Lower Crystallinity | These kinds of polymers have a higher impact resistance, higher flexibility, and no distinct melting temperature |
| Glass Transition Temperature | The polymer goes from a hard, glassy state, to a soft, rubbery state when this temperature is reached |
| Melting Temperature | The polymer goes from a soft, rubbery state to a liquid state when this temperature is reached. This is also when crystalline regions start to break down |
| Clamping | This is the first step in injection molding; the mold is closed |
| Injection | This is the second step in injection molding; the molten plastic is injected into the mold cavity |
| Dwelling | This is the third step in injection molding; pressure is maintained to fill the mold |
| Cooling | This is the fourth step in injection molding; the part cools and solidifies in the mold |
| Mold Opening | This is the fifth step in injection molding; the mold opens |
| Ejection | This is the final step in injection molding; the solidified part is ejected from the mold |
| Cold running | This method of injection mold is cheap, but adds scrap and needs a finishing operation |
| Hot running | This method of injection mold is expensive, but reduces scrap and yields a fully finished part |
| Landfills | The most common way to dispose of waste, occupies a lot of space, but are highly regulated to promote anerobic breakdown |
| Incineration | This method significantly reduces waste volume, methane emissions, and can even recover energy from waste, but can cause unwanted gas emissions |
| Sortation | This process reduces the amount of waste that goes to landfills and incinerators, by taking potential recyclables out of waste |
| Recycling | This process reuses old plastics, metals, and paper to create new products |
Created by:
Tsar Pasta
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