CIVE 2700 Lecture Notes - Lecture 19: Viscoelasticity, Crystallinity, Ultimate Tensile Strength
4 Apr 2016
School
Department
Course
Professor
Document Summary
Natural polymers: used for a long ime; wood, rubber, coton, wool, leather, silk, etc. Ariicial (engineered) polymers: ater wwii; usually beter and cheaper. Commercial polymers: used in large quaniies for their lightweight, corrosion-resistance, and good formability (usually low strength, sifness, and service temp) Engineering polymers: improved strength and elevated temperature properies. The plasics (type of polymer -- other is elastomers) Thermoplasics : coke botles, etc. (not structural); recyclable; can be melted and reshaped. Linear polymer chains (no cross-linkage) i. e. polyethylene, pvc, nylon, Thermoset : non-recyclable; formed/shaped then cured or set permanently by chemical reacion. Very large elasic deformaions when loaded (up to 900% elongaion) Polymer: large chain molecule with high molecular weight on order of several thousands g/mol. Made by adding together (polymerizaion) sub-units (monomers) or structural repeaing units (mers) to form long chains n, degree of polymerizaion: number of repeaing (mer) units in polymer molecular chain.
