this was the experiment. so i need the asnwer of this question. What type of pol
ID: 574639 • Letter: T
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this was the experiment. so i need the asnwer of this question.
What type of polymerization (step-growth or chain-growth) is occurring during the synthesis of these two polyesters? Explain.
POLYESTERS In this experiment, both linear and cross-linked polyesters will be prepared through condensation polymerizations. The linear polyester is prepared through the reaction of phthalic anhydride and ethylene glycol (a di This linear polyester is isometric with Dacron, which is prepared from terephthalic acid and ethylene glycol. Dacron and the linear polyester made in this experiment are both thermoplastics. O. OCH2CH2 Ethylene Glycol - Phthalic anhydride Linear polyester If more than two functional groups are present in one of the monomers, the polymer chains can be linked to one another (cross-linked) to form a three-dimensional network. Such structures are usually more rigid than linear structures and are useful in making paints and coatings. They may be classified as thermosetting plastics. The cross-linked polyester Glyptal will be made in this experiment from phthalic anhydride and glycerol (a triol). O-C OH O HoCH2CHCH20H -OCH2CHCH2 Phthalic anhydride Cross-linked polyesterExplanation / Answer
Step-growth polymerisation is occurring during the synthesis of these two polyesters.
Step-growth polymerisation is also known as condensation polymerisation. Any pair of monomer molecules react to give a step in the condensation reaction like dimer, tetramer, etc.. e,g Dacron. During condensation small molecules like water or methyl alcohol are eliminated. Condensation polymers contain esters or amide linkages.
Chain-growth polymerisation is also known as addition polymerisation. During polymerisation, the addition occurs at the reactive end of the growing chain across the double bond. For example ethylene polymerises to polyethylene in presence of radical initiator.
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