Dependence of molecular weight

Polymerization of Styrene Initialed by Zr(benzyl)t Dependence of Molecular Weight (M ) on Initial Catalyst Concentrations at 30°C in Toluene [Ml. = 6M... 

Polymerization of Styrene by Zr(benzyl)t ([C]o = O.OS M) in Toluene at SO°C. Dependence of Molecular Weights and Polydispersity on Initial Monomer Concentrations... 

The aim of this paper is to offer experimental results for the molecular weight dependence of adsorption of polystyrene-sulfonate) onto a platinum plate from aqueous NaCl solution at 25 °C. Measurements of poly(styrenesulfonate) adsorption were carried out by ellipsometry. The dependences of molecular weight and added salt concentration on the thickness of the adsorbed layer and also the adsorbances of polymer and salt are examined. 

A similar variety of samples was tested for thermal stability by capillary rheometry and TGA. Figure 6.3 shows the viscosity-shear rate dependence for PCTFE homopolymers and one copolymer (Alcon 3000). All materials, save one, showed virtually identical viscosity relationships despite large changes in inherent viscosity. Only the polymers from runs initiated by fluorochemical peroxides (FCP) showed a dependence of molecular weight (as measured by inherent viscosity) upon melt viscosity. 

Figure 1. Dependence of molecular weight on extent of oxidation at 35°C.

Figure 10-3 Estimation of migration (standard test conditions of 10 days/40°C) as a function of Cp0 and in dependency of molecular weight of migrant from a HDPE container of thickness dP = 0.06 cm at a surface/volume ratio of 6 dm2/kg assuming a partition coefficient KPp = 1.

In practice, linear semilogarithmic kinetic plots and linear dependencies of molecular weight on monomer conversion require only that the rate constants of chain transfer and termination are much less than that of propagation klr kp, k,< kp). This is therefore the practical requirement for the synthesis of well-defined polymers, such that complete monomer conversion can be reached and the chain ends can be functionalized quantitatively. However, because chain-breaking reactions are actually present, we prefer to call such systems controlled polymerizations rather than living polymerizations. 

Fig. 1.6. Dependence of molecular weight of polybutadiene and the monomer concentration 97). H202 (40% in H20) 5 g...

The dependence of molecular weight results on these parameters means that great care must be taken to obtain accurate initial calibration constants. Furthermore, standard reference materials are required to check system operation at regular intervals. 

This mechanism is in agreement with the presence of terminal vinylidene groups in polypropene [77], and the dependence of molecular weight on monomer concentration. 

The dependence of molecular weight of polymers on monomer concentration, temperature, Al/Co ratio and conversion are shown in Table 16. As molecular weights are lower than would be calculated from polymer and catalyst concentrations and polymer molecular weights, there is a transfer reaction but its nature is not yet established. Similar findings for the relationship between polymerization variables and molecular weight were found by Zgonnik et al. [170]. 

Various studies found that the absorption of non-oxynol-9 through the vaginal membrane was very slow and suggested a dependence of molecular weight of the oligomeric components that make up the spermicide. Permeation studies have found the hydro-... 

Fig. 33. Irradiation time dependence of molecular weight distribution of insoluble potystyrene having azobenzene groups (content, 4.8 mol%) at 30 °C [64]. Irradiation time (a) 10, (b) 20, (c) 40, (flf) 60, and (e) 90 s. Concentration of the polymer was 0.08 g/dl...

Fig. 2.10 Dependence of molecular weight and activity on the hydrogen concentration.

Figure 7. Ion-content dependence of molecular weight of S-xSSA-...

In most of the published studies on the mathematical simulation of polymer synthesis processes, the attention of investigators has been concentrated on calculating the dependencies of molecular weight (Mn or Mw) and MWD on the parameters of the process. Calculations can be performed for a batch or a continuous reactor (of mixing or displacement), or for a cascade of continuous reactors. 

Table 5.3. Dependence of molecular weight of poly-3,3-bis(chloro-methyl)oxetane) (BCMO) on the concentration of water, ([BCMOJo...

Table 5.4 Dependence of molecular weight of poly-3,3-bis(chloromethyl)oxetane...

Table 5.5. Dependence of molecular weight and molecular weight distribution of poly-3-methyloxetane (MCMO) on conversion [MCMO]0 = 0.55 mol l 1, [(i-C4H9)3Al]0 = 10-2 mol 1-, [H2O]0(ldded) = 3 10 5 mol l1, C6H5C1,...

The observed dependence of molecular weights on time was explained by assuming that in the presence of FS03H, polymerization proceeds initially by chain coupling12) i.e., by the mechanism similar to that described for CF3S03H ... 

The polymerization of VAc by NMP was reported by Matyjaszewski group in 1996. To reduce the bimolecular radical termination dnring the polymerization, the authors attached the stable nitroxyl radical (TEMPO 2,2,6,6-tetramethylpiperidine-l-oxyl radical) to the interior of a dendrimer and used this modified TEMPO ([G-3]-TEMPO) as a scavenger combined with 2,2 -azobis(2-methyl-propionitrile) (AIBN) to polymerize VAc. Fignre 5 shows the kinetic plot and the dependence of molecular weight on monomer conversion for the bnlk polymerization of VAc at 80 °C in the presence of [G-3]-TEMPO/AIBN. 

Figure 7. Dependence of molecular weight and polydispersity on monomer conversion for the bulk polymerization ofVAc with EtIAc as transfer agent and CPD as initiator (50 °C). (m) [VAJq [EtlAcJo [CPDJo = 500 1.0 0.3 (A.) [VA]o [EtIAc] o [CPDJo = 500 1.0 0.5. (Reproduced by the permission from American Chemical Society)...

Figure 8. The dependence of molecular weight on monomer conversion in the bulk polymerization of VAc at 60 °C using AIBN as initiator and MESA as RAFT agent. RAFT agent concentration Cmadix = T1 xlO M (o) 2.2 xKT M (k) ...

Figure 11.6 Meteor on-screen reasoning display showing the dependence of molecular weight and lipophilicity on the likelihood of glycine conjugation with carboxylic acids.

FIGURE 65 The dependences of molecular weight AfM of microgels on curing reaction duration t in Euchdean (1) and fractal (2) spaces for system EPS-l/DDM. 

FIGURE 102 The dependence of molecular weight of repeated link on bulk interactions parameter e for PS-C solutions in tetrahydrofuran (1) and chloroform (2). 

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