Stockmayer-Kennedy theory

At present, there is no comprehensive theory for the chain dynamics of disordered, entangled block copolymers. Using the concept of the tube model, Kim and Han (1992) modified on an ad hoc basis the Stockmayer-Kennedy theory to interpret their experimental results for the linear viscoelastic behavior of disordered, entangled PS-block-PaMS copolymers. They used the expression... 

Let us compare the prediction of the Stockmayer-Kennedy theory with the experimental results for SI diblock copolymers presented in a previous section. The glass transition temperature of the PS block in each SI diblock copolymer is given in Table 8.4. Using ps = 0.68 nm, bp — 0.59 nm, and M = Afp + Afpj in Eq. (8.18), we calculate G (ty) and G co) with the following procedure we calculate using Eq. (8.8),... 

There are several factors that are either not included or assumed to be unimportant in the Stockmayer-Kennedy theory. Hydrodynamic interactions between two chains in a block copolymer are not included in the theory. This can be a serious omission, especially when dealing with low-molecular-weight diblock copolymers, such as the SI diblock copolymers considered above. Intermolecular (thermodynamic) interactions between chemically dissimilar chains are also neglected. Inclusion of such interactions can be important, especially when the chemical affinity between two chemically dissimilar chains is rather poor, such as the case in the SI diblock copolymers considered here. In Chapter 7, which discusses the rheology of miscible polymer blends, we pointed out the importance of the segmental interaction parameter in the prediction of the linear... 

Since the first theoretical attempts in the 1970s (Hall and DeWames 1975 Hansen and Shen 1975a, 1975b Stockmayer and Kennedy 1975 Wang and DiMarzio 1975) to describe the chain dynamics of disordered block copolymers, little progress has been made. The molecular theory for the linear viscoelasticity of disordered block copolymers is still in its infancy. In this section, we present first the currently held linear viscoelasticity theory for unentangled disordered block copolymer and then an extended version for disordered, entangled block copolymer. 

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