Repeating unit of polymer

Repeating unit of polymer chain including solvation Mn of samples not irradiated based on GPC in NMP with polystyrene standards, or by NMR end-group analysis if so indicated Measured net G value after cesium-137 irradiation corrected relative to Fricke dosimeter... 

Coordinating groups Repeating units of polymer ligands... 

The separation of the repeat units of polymers into "backbone" (BB) and "side group" (SG) portions was discussed in Section 2.D. Geometrical parameters, namely the "rotational degrees of freedom" NBBrot and NSoj.0t, will now be defined as heuristic descriptors of flexibility for the backbones and side groups of polymers, respectively, by using the following simple set of rules ... 

Furthermore, in calculations performed manually instead of using software implementing our method, the calculation of the properties of many homopolymers with large repeat units can be simplified by treating them formally as alternating copolymers of smaller repeat units of polymers whose properties have already been calculated. Simple additivity is then assumed to hold for the extensive properties of the alternating copolymer, such as its connectivity indices, cohesive energy, and molar volume. All extensive properties can thus be calculated. Intensive properties, such as the solubility parameter, are defined in terms of extensive properties. Their prediction therefore does not require any detailed calculations either. 

Monomer Repeating unit of polymer Chemical shifts ppm 5 Conditions Ref. 

It is well known that the refractive index (od) can be calculated from the molar refraction [R] and molar volume V according to Lorentz-Lorenz eq. (1), where the molecule is regarded as the repeating unit of polymer structurel-. Abbe s number (Vd) is calculated with no and molar dispersion [AR] from eq. (2) ... 

V molar volume of solvent or a repeating unit of polymer... 

Functionality refers to the moieties chemically distinct from the repeating units of polymer chains. It can be the terminal groups at chain ends or the functional groups deliberately added to a polymer chain. Determination of functionality type distribution of reactive oligomers (telechelics) is an old problem in polymer characterization. The classical method is the combination of SEC separation and functionality sensitive detection. Recent advances of the detection methods such as FT-NMR and MALDl-TOF MS have brought about big improvements in the precision of functionality characterization [12]. 

To understand further the conjugation in the binaphthyl-based polyarylenes, compounds 39 and 40 are synthesized from the reaction of 36 with 1,4-dibromobenzene and 4,4- -dibromobiphenyl, respectively 39 is the repeat unit of polymer (/ )-22 and 40 is that of polymer (/ )-23. The UV spectrum of 39 in methylene chloride solution displays a major absorption at A = 322 nm. The emission of 39 is observed at Ag ,j = 378, 396, and 417 nm when excited at 322 nm. Comparing the UV spectrum of 39 with those of (/ )-22 and rac-22, only a very small red shift ( 6 nm) from the repeat unit to the polymers is observed. The UV spectrum of 40 in methylene chloride solution shows A ,3 = 324 nm. The red shift ( 10 nm) in the absorption maxima from the repeat unit 40 to polymers (/ )-23 and rac-23 is also very small. The emission of 40 is observed at 387, 408, and 418 nm when excited at 324 nm. The absorption spectra of 39 and 40 demonstrate that the conjugation in polymers 22 and 23 is almost the same as that of their repeat units. Table 2 summarizes the UV absorption and fiuore.scence spectroscopic data for 22, 23, 39, and 40. 

From the reaction of 28 with 44, a conjugated molecule 45 is synthesized as the repeat unit of polymers 29 (Scheme 17). The UV spectrum of 45 shows maximum absorptions at = 236, 290, 340, and 374 (sh) nm. These UV absorptions of 42 are about 10 nm blue shifted from those of polymers 29. 

Figure 1. Chemical structure of the repeat units of polymers investigated.

Repeating unit of polymer chain Basic moiety (e.g. imidazole center)... 

In order to correlate the geometry of the repeating units of polymers with transport properties, the following parameters were calculated van der Waals volume (VJ, free volume (Vp, occupied volume accessible volume fractional accessible volume FAV). 

The coefficient c is increased by steric hindrance or restricted rotation of the bond. The repeating unit of polymers is usually composed of various kinds of units, nonpolar or polar. In the case of the repeating unit of a structure of (a) C (CH2)iA-] or (b) [-(CH2)i-CH(A)-], AH, AS, and T x) per repeating unit are expressed respectively as... 

---