can a polymer be formed in both addition and condensation polymerisation?expalin with examples.
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Condensation polymers are any kind of polymers formed through a condensation reaction—where molecules join together—losing small molecules as byproducts such as water or methanol, as opposed to addition polymers which involve the reaction of unsaturated monomers. Condensation polymerization is a form of step-growth polymerization, is a process by which two molecules join together, resulting in loss of small molecules which are often water. The type of end product resulting from a condensation polymerization is dependent on Monomers with only one reactive group do not padlock a growing chain, and thus give end products with a lower molecular weight. Linear polymers are created using monomers with two reactive end groups and monomers with more than two end groups give three-dimensional polymers which are cross linked. Common condensation polymers include polyamides, polyacetals and Proteins
The carboxylic acids and amines link to form peptide bonds, also known as amide groups. Proteins are condensation polymers made from amino acid monomers. Carbohydrates are also condensation polymers made from sugar monomers such as glucose (i.e. cellulose [1] or glycogen) and galactose.
Many exceptions to this rule are products of ring-opening polymerization, which tends to produce condensation-like polymers even though it is an additive process. For example, poly[ethylene oxide] is chemically identical to polyethylene glycol except that it is formed by opening ethylene oxide rings rather than eliminating water from ethylene glycol. Nylon 6 was developed to thwart the patent on nylon 6,6, and while it does have a slightly different structure, its mechanical properties are remarkably similar to its condensation counterpart.
One universal distinction between polymerization types is development of molecular weight by the different modes of propagation. Addition polymers form high molecular weight chains rapidly, with much monomer remaining. Since addition polymerization has rapidly growing chains and free monomer as its reactants, and condensation polymerization occurs in step-wise fashion between monomers, dimers, and other smaller growing chains, the effect of a polymer molecule's current size on a continuing reaction is profoundly different in these two cases. This has important effects on the distribution of molecular weights, or polydispersity, in the finished polymer
The carboxylic acids and amines link to form peptide bonds, also known as amide groups. Proteins are condensation polymers made from amino acid monomers. Carbohydrates are also condensation polymers made from sugar monomers such as glucose (i.e. cellulose [1] or glycogen) and galactose.
Many exceptions to this rule are products of ring-opening polymerization, which tends to produce condensation-like polymers even though it is an additive process. For example, poly[ethylene oxide] is chemically identical to polyethylene glycol except that it is formed by opening ethylene oxide rings rather than eliminating water from ethylene glycol. Nylon 6 was developed to thwart the patent on nylon 6,6, and while it does have a slightly different structure, its mechanical properties are remarkably similar to its condensation counterpart.
One universal distinction between polymerization types is development of molecular weight by the different modes of propagation. Addition polymers form high molecular weight chains rapidly, with much monomer remaining. Since addition polymerization has rapidly growing chains and free monomer as its reactants, and condensation polymerization occurs in step-wise fashion between monomers, dimers, and other smaller growing chains, the effect of a polymer molecule's current size on a continuing reaction is profoundly different in these two cases. This has important effects on the distribution of molecular weights, or polydispersity, in the finished polymer
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