BBE 1001 Lecture Notes - Lecture 13: Hydrophobe, Carbohydrate, Kenaf
16 Dec 2017
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Document Summary
Polymers that soften on heating and solidify on cooling. Change occurs at the glass transition temperature. Glass transition temperature: glassy state rubbery state. Polymers that soften or become viscous/liquid when heated. Mixture (fluid state) of polymer and other additives is forced through shaping orifice. Mixture of polymers and additives is forced into the cavity of a closed mold. Mixture placed on the bottom half of a heated mold. Mixture is held in place/shape until cooled. Mixture containing plastic that is either molten, in solution or suspension, is deposited on a surface, and solidified upon cooling or solvent evaporation. Carbohydrate (corn starch) fermentation lactic acid (direct polymerization) Or lactide (dimer) (ring opening polymerization) Brittle as compared to plastics like pet. Degradation rate and hydrophobicity may be a problem in biomedical applications. Properties vary depending on the r-group (alkyl group. Directly by bacteria in the presence of excess sunlight and under limited nutrient conditions.
