Answer to Question 1
In any material, especially one in which the polymer repeating unit is large, energy must be added to the system to allow sufficient molecular motion to align the molecules for crystallization. This is known as the thermodynamic limit of crystallization. If the polymer is oriented, some induced bonding has been created that gives the structure stability. Therefore, to rearrange into crystals, more energy must be added than if the polymer were amorphous. Therefore, the oriented polymers require higher temperatures to crystallize than the nonoriented polymers.
Answer to Question 2
Plastics or ceramics would be better than metals because the metals would conduct the heat and burn your hand. Ceramics are quite brittle, so plastics would be the first choice. Among the plastics, most are good thermal insulators, but the thermoplastics would likely soften or melt when the pan got hot. Therefore, thermosets are the likely group of plastics to consider. Within the thermosets, some properties that might be important are low flammability, low cost, and stiffness. Phenolics seem to be a good choice. The potential drawbacks of phenolics are color (the part will be dark) and filler
Taking a Patient’s Axillary Temperature
A speculum used to hold the vagina open in order to visualize the cervix.
Temperature Changes on Heart Rate
The main avenue to the upward social mobility reviewed in the text has been higher education.
The bimetallic temperature sensor spring controls the amount of silicone that is allowed into the ...
Jan-Dec Global Mean Temperature Over Land and Ocean