Crosslinking figure

To determine the crosslinking density from the equilibrium elastic modulus, Eq. (3.5) or some of its modifications are used. For example, this analysis has been performed for the PA Am-based hydrogels, both neutral [18] and polyelectrolyte [19,22,42,120,121]. For gels obtained by free-radical copolymerization, the network densities determined experimentally have been correlated with values calculated from the initial concentration of crosslinker. Figure 1 shows that the experimental molecular weight between crosslinks considerably exceeds the expected value in a wide range of monomer and crosslinker concentrations. These results as well as other data [19, 22, 42] point to various imperfections of the PAAm network structure. 

Extent of Crosslinking. Figure 7 shows plots of log E versus... 

FIXED NEGATIVELY CHARGED EXCHANGE SITE l-E. Oj MOBILE POSITIVELY CHARGED EXCHANGEABLE CATION POLYSTYRENE CHAIN DIVlNYLBENZENE CROSSLINK FIGURE 21.2-1 Representation of an ton-exchange membrane. 

Furthermore, CS applications can be improved by synthesising some of its diverse derivatives. CS has an amino group, which allows the opportimity for N-alkylation, N-carboxylation, cyclisation and crosslinking (Figure 2.4). These derivatives possess good rheological and autoassociative and surface-active characteristics [20-23]. 

However, the polystyrene end blocks can still be chemically cross-linked. In this case, the end blocks serve both as the physical crosslinks, and as the locus of the chemical crosslinks. Figure 1 5 illustrates the possible locations of chemical crosslinks in a triblock copolymer that has its end blocks chemically crosslinked. 

Interstrand crosslink DNA-protein crosslink Intrastrand crosslink Figure 2 General crosslinked forms of DNA from reaction with cisplatin. 

Four different polymer molecular chain structures are possible linear (Figure 14.7a), branched (Figure 14.7h), crosslinked (Figure 14.7c), and network (Figure lA.ld). 

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