Monomer system, total

These include the variations of sacrificial anode, sonication, and alternating polarity cell mentioned above, different solvent/co-solvent and electrolyte systems, monomer concentration, total current passed, and temperature. Best results appear to be obtained with THF and dimethyl ether (DME) as solvent and a perchlorate supporting electrolyte in some systems using fluorides, electrolyte decomposition occurred releasing fluoride anion which formed unreactive fluorosilanes.125... 

Total mass of monomer introduced into the system Total mass of deposition W2 Total mass exits from the reactor W3 Monomer-polymer conversion ratio ... 

For simplicity of discussion, let us consider a simple monomer system and treat the monomer as an ideal gas. From the kinetic theory of gases, the ratio of gas-wall collisions to gas-gas collisions in the total system is proportional to the surface to volume ratio SjV for a given monomer at fixed pressure and temperature. 

Individual and k values can be obtained by experimental determination of individual concentrations of free ions and ion pairs by a combination of conductivity and short-stop experiments. While conductivity directly yields the concentration of free ions (that is, only free ions conduct), short-stop experiments yield the total concentration of ion-pairs and free ions. For mostly aromatic monomers the total concentration of ion pairs and free ions may also be obtained by UV-visible spectroscopy, assuming that ion pairs show the same UV-visible absorption as free ions since the ion pairs in cationic systems are loose ion pairs (due to large size of the negative counterions). 

If Nq is the original number of molecules present in an A-B monomer system and N is the number of all molecules remaining after time t, then the total number of functional groups of either A or B that have reacted is (Nq- N). At that time t, the extent of reaction p is given by... 

When a chain moves in a dense system (like a polymer melt), the frictional forces acting on each monomer are totally independent. Hence, the total frictional force experienced by the moving chain is simply the sum of the frictional forces on each individual monomer. How can we find these frictional forces on the monomers Let s focus on one monomer suppose it has a velocity v. This is the velocity of diffusion, so it is not too high. (To be more precise, it is of the same order as the thermal velocity of the monomer.) This gives us the right to take the force f of viscous friction to be proportional to the velocity f = —pv. Here p is the coefficient of friction for a single monomer. Since the total friction is the sum over all the monomers, the same must be true for the coefficients of friction. The... 

A mixture of equimolar amounts of the meta and nra formals in Scheme 22 was let to equihhrate in the same solution (chloroform, 25°C, in the presence of catalytic CF3SO3H) at increasing total monomer (meta + para) concentration. As in the case of one-monomer systems, saturation profiles were also observed for the equilibrium concentrations of cychc species on increasing the total monomer concentration. 

When the cyclic dimers reach their plateau value (x 1), the total monomer (meta + para) concentration is well above the critical concentration. Under this condition, p andp , coincide with the initial mole fractions of the two monomers (equal to 0.5), because the distribution of monomeric units within the linear fraction is always purely statistical, and when the total monomer concentration is well above the CC, the statistical linear fraction overwhelms the nonstatistical contribution of the cyclic fraction. Since the EM values of 12 and 14 (EM21 = 13.4 mM and EM23 = 0.30 mM) were known from previous one-monomer DL experiments (see Section 4.1.3), we can expect that the plateau values for the concentrations of homodimers 12 and 14 are J4 of their EM values, that is, 3.35 mM and 0.075 mM, respectively. The plateau value for concentration of homodimer 12 in the two-monomer system was indeed found to be 3.2 mM which is very close to the estimated value, whereas that of the homodimer 14 was too low to be detected, again in accordance with the estimated low value. Saturation value for the equilibrium concentration of heterodimer 13 was 11.4 mM which corresponds to EM22 = 11.4/0.5 = 22.8 mM. It should be stressed... 

The results obtained are summarized in Table 6. A longer alkyl chain of the acrylate monomer caused a decrease in its conversion. Block copolymers formed in these alkyl acrylate monomer systems constituted about 85% of the total polymers. 

In anionic polymerization, r, = Vp, unlike free-radical polymerization, where r, Tp. Hence, chains start growing rapidly. Also, for very pure systems, termination does not occur. As a result, the chains can grow until the monomer is totally used. Adding more monomer causes the reaction to continue. 

During release of the substrate with cured information layer from the mold, it is warped in a complicated way. One part of the total separation energy is required for the actual separation (release of adhesion), the remaining part for the (in)elastic deformation of the substrate with information layer. Table 3 shows that the release is easiest for the one-monomer system, although satisfactory results were obtained in all three cases. 

The second context is the process reac tor. There is a potential for a runaway if the net heat gain of the system exceeds its total heat loss capabihty. A self-heating rate of 3°C/day is not unusual for a monomer storage tank in the early stages of a runaway. This corresponds to 0.00208°C/min, 10 percent of the ARC s detection limit. ARC data for the stored chemical would not show an exotherm until the self-heating rate was 0.02°C/min. Therefore, onset temperature information from ARC testing must be used with considerable caution. 

With the total number of monomers and the volume of the system fixed, a number of statistical averages can be sampled in the course of canonical ensemble averaging, like the mean squared end-to-end distance Re), gyration radius R g), bond length (/ ), and mean chain length (L). 

The changes in the average chain length of a solution of semi-flexible selfassembling chains confined between two hard repulsive walls as the width of the sht T> is varied, have been studied [61] using two different Monte Carlo models for fast equihbration of the system, that of a shthering snake and of the independent monomer states. A polydisperse system of chain molecules in conditions of equilibrium polymerization, confined in a gap which is either closed (with fixed total density) or open and in contact with an external reservoir, has been considered. 

A numerical study of the MMEP kinetics, as described by the system of nonlinear differential equations (26), subject to mass conservation (Eq. (27)), has been carried out [64] for a total number of 1000 monomers and different initial MWDs. As expected, and in contrast to the case of wormlike micelles, it has been found that during relaxation to a new equilibrium state the temporal MWD does not preserve its exponential form. 

Keeping the composition of copolymerization media constant the total comonomer concentration of which is varied. The absorbed dose was kept constant at 0.14 KGy for the AM-AANa and at 0.35 KGy for the AM-DAEA-HCl systems. The results are shown in Figs. 4 and 5, which show the rate of polymerization, Rp, the degree of polymerization, and the intrinsic viscosity increase with increasing monomer concentration. At comonomer concentration >2.1 M/L, DPn decreases with increasing comonomer concentration. From the logarithmic plots, exponents of the comonomer concentration for the AM-AANa system were determined to be [17,54]. 

Concentrations of the monomer, solvent, polymer, and initiator System temperature Partial pressures of the monomer, solvent, and nitrogen Total pressure... 

Data of Nomura and Funita (12). The predictive capabilities of EPM for copolymerizations are shown in Figures 8-9. Nomura has published a very extensive set of seeded experimental data for the system styrene-MMA. Figures 8 and 9 summarize the EPM calculations for two of these runs which were carried out in a batch reactor at 50 °C at an initiator concentration of 1.25 g dm 3 water. The concentration of the seeded particles was 6x10 dm 3 and the total mass of monomer was 200 g dm 3. The ratio of the mass of MMA to the total monomer was 0.5 and 0.1 in Figures 8 and 9 respectively. The agreement between the measured and predicted values of the total monomer conversion, the copolymer composition, and the concentration of the two monomers in the latex particles is excellent. The transition from Interval II to Interval III is predicted satisfactorily. In accordance with the experimental observations, EPM predicted no new particle formation under the conditions of this run. 

Model predictions are caipared with experimental data In the case of the ternary system acrylonitrlle-styrene-methyl methacrylate. Ihe experimental runs have been performed with the same recipe, but monomer feed composition. A glass, thermostat ted, well mixed reactor, equipped with an anchor stirrer and four baffles, has been used. The reactor operates under nitrogen atmosphere and a standard degassing procedure is performed Just before each reaction. The same operating conditions have been maintained in all runs tenperature = 50°C, pressure = 1 atm, stirring speed = 500 rpm, initiator (KgSgOg) 0. 395 gr, enulsifier (SLS) r 2.0 gr, deionized water = 600 gr, total amount of monomers = 100 gr. 

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