Specification of the Polymer

This effect has particular relevance for the specificity of the polymer. Figure 6.25 illustrates that, for a non-template ligand, provided one or more reciprocal functional groups are present and steric restraints are minimal, cross-reactive binding can occur. 

Figure 5. Dependence of the specificity of the polymers on the kind and the amount of crosslinking. Polymers imprinted with were prepared with varying amount of the crosslinking agents ethylene glycol dimethacrylate, butanediol dimethacrylate, and p-divi-nylbenzene. After splitting off the templates the separation factor a for the optical resolution of phenyl-a-D,L-mannoside in the batch procedure was determined.

On-line estimation may also be accomplished using first-principles polymerization kinetic models implemented on-line in the form of an extended Kalman filter (EKF) (as illustrated for example in Refs. 8 and 40-42). It should be pointed out that the choice of techniques for on-line estimation of polymer properties is still an active area of research and is very much dependent on the specifics of the polymer chemistry and available on-line instrumentation. 

The specificities of the polymer flow during the filling stage have also to be taken into account. The flow can be divided into two parts [136] ... 

In this connection, it has been suggested that non-traditional solution of creation of gradient optical media - the method of controlled gradient formation - may provide the possibility of obtaining thin-layer materials based on polymerization and polycondensation polymers with great surface area and preliminarily given radial (axial) distribution of the refractive index, with no dependence on the aggregate state and chemical nature of appropriate monomers that determine the specificity of the polymer synthesis [61,127 -133],... 

The remaining step is to eliminate those terms which refer to the subchain by expressing them in terms of the polymer molecule as a whole. Specifically, we recall that (r ) = n l, = n f, and = n/n. Substituting into Eq. (3.97),... 

The amount of plasticizer added to the polymer in question varies, depending on the magnitude of the effect required. For example, a small addition of plasticizer may be made simply to improve the workabiUty of the polymer melt. This contrasts with larger additions made with the specific intention of completely transforming the properties of the product. For example, PVC without a plasticizer, ie, unplasticized PVC (PVC-U), is used in appHcations such as pipes and window profiles with plasticizer added, articles such as PVC food film, PVC cable insulation, and sheathing and PVC floorings are formed. 

The plasticization of PVC accounts for the vast majority of plasticizer sales. However, significant amounts of plasticizers are used in non-PVC polymers and this may become increasingly important in the future. Although PVC stands alone in its abiUty to accept and retain large quantities of commercial plasticizer, effective plasticization of other resins using slightly modified plasticizers may be possible if certain conditions specific to the polymer of interest are met. 

The viscosity ratio or relative viscosity, Tj p is the ratio of the viscosity of the polymer solution to the viscosity of the pure solvent. In capillary viscometer measurements, the relative viscosity (dimensionless) is the ratio of the flow time for the solution t to the flow time for the solvent /q (Table 2). The specific (sp) viscosity (dimensionless) is also defined in Table 2, as is the viscosity number or reduced (red) viscosity, which has the units of cubic meters per kilogram (m /kg) or deciUters per gram (dL/g). The logarithmic viscosity number or inherent (inh) viscosity likewise has the units m /kg or dL/g. For Tj g and Tj p, the concentration of polymer, is expressed in convenient units, traditionally g/100 cm but kg/m in SI units. The viscosity number and logarithmic viscosity number vary with concentration, but each can be extrapolated (Fig. 9) to zero concentration to give the limiting viscosity number (intrinsic viscosity) (Table 2). 

---