Physical Gelation of Synthetic and Biological Macromolecules

摘要: Historically, polymer networks can be divided into two main classes, chemically cross-linked materials (including bulk elastomers), and ‘entanglement networks’. The latter are formed by the topological interaction of chains, either in melt or solution when product concentration molecular weight becomes greater than some critical Me.1,2 In this case they behave as ‘pseudo gels’ at frequencies higher (timescales shorter) lifetime entanglements. This depends for linear chains on Mr 3, where is weight. covalently materials, other hand, a variety routes including cross-linking high radiation, end-linking reactant with branching unit, step-addition polymerisation oligomeric multifunctional precursors. They true macromolecules, nominally infinite, therefore possess an infinite relaxation time equilibrium modulus.1