Characteristic properties of polymer solutions

Polymers in solution phases have a high degree of freedom for translational and internal motion. They change their conformations randomly by Brownian movements. The purpose of this section is to see how these molecular characteristics of polymers lead to the macroscopic properties of the polymer solutions. 

Measurements to find the characteristics of each polymer chain are carried out by separating them from each other in solution. Knowing the fundamental properties of polymer solutions, in particular dilute solutions, is very important for the molecular 

The number of -component molecules/total number of molecules in the mixture 

The volume occupied by /-component molecules/total volume of the mixture 

The weight of the /-component/total weight of the mixture (dimensionless [wt %]). 

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It has been recognised for several decades that most of the characteristic properties of polymers (except the untypical globular proteins), such as their high solution and melt viscosities, their rubber-like elasticity, and their viscoelastic behaviour generally, can be ascribed to the fact that their molecules, unless constrained as in the crystal, are free to adopt extended but coiled configurations, so that each molecule affects a region of space of many times its own volume ... 

This book presents coverage of the dynamics, preparation, application and physico-chemical properties of polymer solutions and colloids. It also covers the adsorption characteristics at and the adhesion properties of polymer surfaces. It is written by 23 contemporary experts within their field. Main headings include Structural ordering in polymer solutions Influence of surface Structure on polymer surface behaviour Advances in preparations and appUcations of polymeric microspheres Latex particle heterogeneity origins, detection, and consequences Electrokinetic behaviour of polymer colloids Interaction of polymer latices with other inorganic colloids Thermodynamic and kinetic aspects of bridging flocculation Metal complexation in polymer systems Adsorption of quaternary ammonium compounds art polymer surfaces Adsorption onto polytetrafluoroethylene from aqueous solutions Adsorption from polymer mixtures at the interface with solids Polymer adsorption at oxide surface Preparation of oxide-coated cellulose fibre The evaluation of acid-base properties of polymer surfaces by wettability measurements. Each chapter is well referenced. 

From about 1910 onwards, physical chemists began studying the characteristics of polymer solutions, measuring such properties as osmotic pressure, and found them... 

Dendrimers have distinctive properties, such as the ability to entrap small molecules in their core region and very low intrinsic viscosities in solution. Such properties require molecules to have achieved a particular size, and not all molecules with branches radiating from a core are large enough to develop the characteristic properties of true dendrimers. Branched molecules below this critical size are called dendrons and are the equivalent in dendrimer chemistry of oligomers in polymer chemistry. 

In the previous sections, we described the overall features of the heat-induced phase transition of neutral polymers in water and placed the phenomenon within the context of the general understanding of the temperature dependence of polymer solutions. We emphasised one of the characteristic features of thermally responsive polymers in water, namely their increased hydropho-bicity at elevated temperature, which can, in turn, cause coagulation and macroscopic phase separation. We noted also, that in order to circumvent this macroscopic event, polymer chemists have devised a number of routes to enhance the colloidal stability of neutral globules at elevated temperature by adjusting the properties of the particle-water interface. 

To explore further the characteristic properties of membranes derived from PTFE films, several attempts were made to graft mixtures of AA and VP or to graft the two monomers in two successive steps. Both techniques failed because a spontaneous reaction occurs when 4-VP is brought in contact with AA (or its polymer), leading to the formation of a reddish-brown polymer which is extracted readily by acidic or alkaline solutions. 

One of the characteristic properties of rod-like polymers is that their concentrated solutions form lyotropic liquid crystals51. Such examples among synthetic polymers are polyamides52,53 and polyisocyanates54 which form cholesteric or nematic liquid crystals in selected solvents. 

The problem of the relationship between the equilibrium and the kinetic rigidity of the chain is of paramount importance since both the behavior of a chain molecule in solution and the main properties of polymer materials are related to these molecular characteristics. 

A high segment length value A of rigid chain polymers leads to many characteristic hydrodynamic properties of their solutions differing from those of flexible polymers. 

As already indicated, (p. 170) the dispersion of the Kerr effect in the range of radio frequencies is a characteristic property of rigid-chain polymer solutions. This can be seen in Figs. 59-61 which show frequency dependences of EB for solutions of polj chlorohexyl isocyanate)s, cellulose earbanilate and ladder polychlorophenylsiloxane. Similar dependences have been obtained for poly(butyl isocyanate) various cellulose ethers and esters and ladder polysiloxanes ... 

Intrinsic viscosity [q] is a characteristic property of an isolated polymer molecule in a given solvent and it represents a measure of its hydrodynamic volume. Capillary viscosity is often used for the measurement of [q of polymer solutions, although for some uses, a more conventional concentric cylinder viscometer is preferred (Ross-Murphy, 1994). Two viscosity values are measured using a capillary viscometer one is the viscosity of the solvent, qs, and the other is the viscosity of the polymer solution, q. From qs and q, relative viscosity (qr), which is the viscosity enhancement due to the contribution of the polymer, is obtained ... 

A standard commercial film blowing LLDPE resin, LPX-30, was blended at different ratios with either other LLDPE s or a LDPE polymer. The characteristic properties of these materials are listed In Table II. The resins were generously donated to the project by Esso Chem., Canada. Prior to blending the polymers were thoroughly characterized by SEC, SEC/LALLS, solution viscosity, CNMR, Atomic Absorbance, and their rheological behavior was characterized In steady state and dynamic shear flow as well as In the uniaxial extenslonal deformation (44-46). 

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