BIOE-324 Lecture 9: BIOE 324 lecture 9
21 Feb 2019
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Document Summary
Biopolymers sugarcane residue ) in place of glass or carbon. E. g. fiberboard: natural fiber bonded with phenolic resin for uses as wood: bio-derived composites. Composites containing natural fibers (hemp, flax, kenaf, wheat or rice husk, bamboo: wood, paper. Can be reversibly cooled & reheated, i. e. recycled. Heat until soft, shape as desired, then cool. When heated forms a molecular network (chemical reaction) A prepolymer molded into desired shape, then chemical reaction occurs. Thermoplastics and thermosets: polymer and additives placed in mold cavity, mold heated and pressure applied, fluid polymer assumes shape of mold. First, a parison , length of polymer tubing, is extruded . While still in a semimolten state, the parison is placed in a two -piece mold having the desired container configuration . The hollow piece is formed by blowing air or steam under pressure into the parison , forcing the tube walls to conform to the contours of the mold .
