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A monomer (/ ˈ m ɒ n ə m ər / MON-ə-mər; mono-, "one" + -mer, "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization.
In dilute solutions, the properties of the polymer are characterized by the interaction between the solvent and the polymer. In a good solvent, the polymer appears swollen and occupies a large volume. In this scenario, intermolecular forces between the solvent and monomer subunits dominate over intramolecular interactions.
While the elementary model described above is totally unadapted to the description of real-world polymers at the microscopic scale, it does show some relevance at the macroscopic scale in the case of a polymer in solution whose monomers form an ideal mix with the solvent (in which case, the interactions between monomer and monomer, solvent molecule and solvent molecule, and between monomer and ...
More interaction between polymers tends to enhance the interaction strength between polymers. The association rate and dissociation rate of interacting groups in polymer molecules determine intermolecular interaction strength. For supramolecular polymers, the dissociation kinetics for dynamic networks plays a critical role in the material ...
The simple reactive molecule from which the repeating structural units of a polymer are derived is called a monomer. A polymer can be described in many ways: its degree of polymerisation, molar mass distribution, tacticity, copolymer distribution, the degree of branching, by its end-groups, crosslinks, crystallinity and thermal properties such ...
Step-growth polymers are formed by independent reaction steps between functional groups of monomer units, usually containing heteroatoms such as nitrogen or oxygen. Most step-growth polymers are also classified as condensation polymers , since a small molecule such as water is lost when the polymer chain is lengthened.
Thus in the case of a functionality of f = 2 a linear polymer is formed by polymerizing (a thermoplastic). Monomers with a functionality f ≥ 3 lead to a branching point, which can lead to cross-linked polymers (a thermosetting polymer). Monofunctional monomers do not exist as such molecules lead to a chain termination. [6]
However, for high molecular weight polymer chains (i.e. small initiator to monomer ratio) the Mn is not easily to controlled, for some monomers, since self-condensation between monomers occurred more frequently due to the low propagating species concentration. [22]