Volume of polymer

Initially, all of the SBR polymer known as GR-S produced during World War II was by the batch process. Later, it was thought that a higher volume of polymer would be needed for the war effort. The answer was found in switching from batchwise to continuous production. This was demonstrated in 1944 at the Houston, Texas, synthetic mbber plant operated by The Goodyear Tire Rubber Company. One line, consisting of 12 reactors, was lined up in a continuous mode, producing GR-S that was mote consistent than the batch-produced polymer (25). In addition to increased productivity, improved operation of the recovery of monomers resulted because of increased (20%) reactor capacity as well as consistent operation instead of up and down, as by batchwise polymerisation. 

The solubihty coefficient must have units that are consistent with equation 3. In the hterature S has units cc(STP)/(cm atm), where cc(STP) is a molar unit for absorbed permeant (nominally cubic centimeters of gas at standard temperature and pressure) and cm is a volume of polymer. When these units are multiphed by an equihbrium pressure of permeant, concentration units result. In preferred SI units, S has units of nmol /(m GPa). 

The quantity soibed ATf is simply the volume of polymer affected times the average concentration. The volume affected is the package area... 

Universal SEC calibration reflects differences in the excluded volume of polymer molecules with identical molecular weight caused by varying coil conformation, coil geometry, and interactive propenies. Intrinsic viscosity, in the notation of Staudinger/ Mark/Houwink power law ([77]=fC.M ), summarizes these phenom-... 

Acrylic esters can be polymerized by a number of routes. Anionic polymerization gives the narrow standards used primarily for calibration, but is not used on an industrial/commercial scale. Free-radical polymerization is the dominant mode of polymerization for making these polymers on an industrial scale. Significant volumes of polymer are made by both solution polymerization... 

With use of a THF/n-Heptane mixture for example, in GPC 2 the hydrodynamic volume of polymer mola ules rich in one monomer component can be much more affected than those rich in the other. Steric exclusion paration can then distinguiA compsitional differences. 

Hydrodynamic volume of polymer (here considered equivalent to the separation parameter KM Table II for GPC calibration)... 

Several review articles focusing on the contribution of polymeric materials to nanomedicine have been published. This volume of Polymers in Nanomedicine in the series Advances in Polymer Science will be one of the pioneering review books dedicated to the study of polymer science for medical nanotechnology. 

For any given size of mill there is a minimum volume of polymer per unit width of roll, below which no dispersive mixing occurs. Increasing the amount of material above this minimum level increases the high shear zone in the polymer, increasing dispersive mixing. There is an upper limit however, above which a circulatory flow develops at the entrance to the nip region and no further improvement occurs. 

The amounts of NH Br deposited in the polymer were determined, in most cases, from weight increase. In the case of small concentrations of NH Br, the polymer was dissolved in a solvent and the remaining NH Br determined argentometrically. Density was determined by weighing known volumes of polymer. 

This apparent anomaly may be due to increased dipolar contributions as well as to possible decrease in the free volume of polymer. Free volumes of the resin... 

CaHpSi 0 + 2a+V20+2r)-n)O -> otC02 + K0H2O + r)Si02 (3) then the volume of polymer consumed per 0 atom is given by... 

Further development of the Flory-Huggins method in direction of taking into account the effects of far interaction, swelling of polymeric ball in good solvents [4, 5], difference of free volumes of polymer and solvent [6, 7] leaded to complication of expression for virial coefficient A and to growth of number of parameters needed for its numerical estimation, but weakly reflected on the possibility of equation (1) to describe the osmotic pressure of polymeric solutions in a wide range of concentrations. 

V, is the molar volume of polymer or solvent, as appropriate, and the concentration is in mass per unit volume. It can be seen from Equation (2.42) that the interaction term changes with the square of the polymer concentration but more importantly for our discussion is the implications of the value of x- When x = 0.5 we are left with the van t Hoff expression which describes the osmotic pressure of an ideal polymer solution. A sol vent/temperature condition that yields this result is known as the 0-condition. For example, the 0-temperature for poly(styrene) in cyclohexane is 311.5 K. At this temperature, the poly(styrene) molecule is at its closest to a random coil configuration because its conformation is unperturbed by specific solvent effects. If x is greater than 0.5 we have a poor solvent for our polymer and the coil will collapse. At x values less than 0.5 we have the polymer in a good solvent and the conformation will be expanded in order to pack as many solvent molecules around each chain segment as possible. A 0-condition is often used when determining the molecular weight of a polymer by measurement of the concentration dependence of viscosity, for example, but solution polymers are invariably used in better than 0-conditions. 

Molecular rotors allow us to study changes in free volume of polymers as a function of polymerization reaction parameters, molecular weight, stereoregularity, crosslinking, polymer chain relaxation and flexibility. Application to monitoring of polymerization reactions is illustrated in Box 8.1. 

Deka and Saikia (2000) treated softwood Anthocephalus cadamba) with methanolic solutions of PF, MF or UF resins. At aronnd 34 % resin loading, the wood samples exhibited volnme increases of 14 % (PF), 12 % (MF) and 9 % (UF), which was nearly equal to the calculated volume of polymer added, showing that most of the resin was located in the cell wall. Resin loadings higher than 34 % resulted in no further volume increase of the wood. Increases in ASF also exhibited the same behaviour, with the highest values (around 70 % for PF and MF, and 50 % for UF) found at about 34 % resin loading. Both the MOE and the MOR of treated samples increased with resin loading. 

Therein and Vggi represent the molar volumes of polymer and solvent re-... 

A direct consequence of the development of hydrodynamic volume theory In SEC has been the universal calibration method as introduced by Benoit (17). Universal calibration methodology is based upon the fact that retention in SEC can be described as a function of the hydrodynamic volume of polymer molecules. 

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