Type II polymer

Fig. 7 Structure of the Arabinogalactan type II polymer from Larch...

Already in 1988 and 1991, Gao et al. [65,66] detected four different polysaccharides present in the leaves of Panax ginseng that had an effect on the complement system, but only two of them, the neutral, GL-NIa, and one of the acidic ones, GL-AIa, had potent activities at low concentrations. GL-NIa was found to be mainly an arabinigalactan type II polymer. GL-AIa was a polysaccharide with a rhamnogalacturonan core with neutral side chains of the AG-II type, confirmed by a strong reaction with the Yariv reagent and the methylation results. It was shown that the crude polysaccharide fraction contained KDO and DHA, suggesting the presence of Rhamnogalacturonan II in... 

The same derivation holds for type ii polymers formed from precisely equivalent proportions of A------A and B------B reactants. Here... 

X represents the combined number of both types of units in the polymer chain. Eq. (3) applies also to polymers stabilized (see Chap. Ill) with small amounts of monofunctional units, although here it becomes necessary to replace the extent of reaction p with another quantity, namely, the probability that a given functional group has reacted with a bifunctional monomer. Type ii polymers stabilized with an excess of one or the other ingredient will be discussed later. 

The weight fraction of rings Wr in a type ii polymer is plotted against the extent of reaction in Fig. 54 for several values of B Mo/c. These... 

Fig. 54.—Weight fraction Wr of rings vs. the extent of reaction p for a type ii polymer for B Mo/c =0.005 (lowest curve), 0.05 (middle curve), and 0.5 (uppermost curve). The curves correspond to successively increasing dilutions. (Jacobson and Stockmayer." )...

Fig. 55.—Weight fraction distribution of cyclic polymers for a type ii polymer with B Mo/c = 0.01 (g./cc.) as calculated from Eq. (16) for p =0.95 and 1.00 (solid curves) only even integral values of x apply. The chain distribution for p =0.95 is shown for comparison by the broken curve calculated from Eq. (3 ), p. 330.

An interesting example of the application of the theory is a prediction of a new route to polyamantane by polymerization of -quinodi-methane 121h The first step would be n-n overlapping interaction. The HO and LU of quinodimethane are indicated in Fig. 7.40 a. The mode of n HO-LU interaction and the possible structure of polyamantane derived therefrom (Type I polymer) can be seen in Fig. 7.40b. On the other hand, the direction of the hybridization change would be controlled by the a-n interaction. The nodal property of n HO and a LU of the monomeric unit are as shown in Fig. 7.40 c, so that the hybridized states of carbon atoms might change into the form illustrated in Fig. 7.40d to lead to the Type II polymer. 

On the basis of a catalytic system previously developed by the same group, Nicholls and collaborators [51] reported the preparation of an imprinted polymer for enantioselective formation of a C-C bond with properties of a metallo-enzyme aldolase type II. Polymers were imprinted using the two enantiomers of a 1,3-diketone, the (l.S, 35,45)-(75), and the corresponding (l/ ,3/ ,4/ )-(75), together with two 4-vinyl-pyridine held in place by a Co(II). The cross-aldol condensation... 

Fig. 1 Band offsets, i.e., relative HOMO/LUMO energies, for two representative type II polymer junctions, i.e., the TFB F8BT and PFB F8BT heterojunctions. Both are fluorene-based polymer materials [26,33]. In this chapter, we focus on the TFB F8BT junction.

Fig. 54 Potential energy diagram describing the energetics and kinetics at type II polymer heterojunctions. The energetic order of A D")r = oo and A D)r = oo may be reversed for PFB F8BT vs TFB F8BT. The inset shows the band offsets at a type II heterojunction. (Reprinted with permission from [57], 2004, American Physical Society)...

Type II polymers with pendant metal complexes Polymers containing bipyridyl and terpyridyl metal-binding sites... 

Figure 2. Three step synthesis of polyurethanes - Type II polymers...

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