Grafting rate

Mand P represent the initiator, the monomer and polypropylene, respectively, the following equation for the grafting rate ... 

Solvent Effects on Grafting Rate and Surface Properties. 

As has been shown in Figure 4, the grafting rate decreased with the increase in the unsaturated groups contained in the polyethylenes. This result may indicate that the rate constants of the re-initiations (8-1)-(8-3) are considerably smaller than that of propagation (6). 

Type Concn., % Dose Rate, rads/hr. Dose, megarads Graft, % Grafting Rate, %/megarad... 

In all cases, the authors propose technical solutions permitting one to reach non-negligible grafting rates knowing that the maj ority of natural starting compounds contain substances such as phenols inhibiting all polymerization of monomers when using conventional methods. So, ozonization... 

Heinze et al. found that DMSO in combination with tetrabutylammonium fluoride trihydrate dissolved cellulose (degree of polymerization < 650) within 15 min at room temperature [38]. They also demonstrated that homogeneous esterification of cellulose is possible in this solvent system. The applicability of this new solvent system to cellulose grafting has recently been proved by adoption of cyclic compounds such as lactones and N-carboxy a-amino acid anhydrides (NCAs) [39]. e-Caprolactone was facilely graft-polymerized on cellulose at a graft rate of 65% (per trunk weight of 100), and NCAs at over 100%, in the respective homogeneous reaction systems at < 60 °C. 

In order to take into consideration the effects of diverged reactivities of graft radicals, we divided reacting sites into several parts, and kinetic parameters for respective regions were determined as follows. Over-all grafting rate is given by... 

Figure 1. Grafting rate using two sodium bisulfate initiator systems. Lignin (g%)...

Figure 5. Grafting rate of two monomers. Conditions initiator, ceric ammonium sulfate (0.08 g/100 mL, 1% HtSOu). Lignin (g%) using ethyl acrylate (40°C) ...

Figure 6. Grafting rate of semichemical pulp. Conditions initiator, ceric ammonium sulfate (0.08 g/100 mL, 1% HsSO 30°C. Key (monomer) O—O, acrylonitrile — , ethyl acrylate. Grafting rate of extracted bagasse. Conditions monomer, ethyl acrylate 60°C. Key (initiator, ceric ammonium sulfate) X—X, 0.08 g/100 mL, 1% H,SOi ----------------------b 0.10 g/100 mL, 1% H2SOt.

Figure 9. Grafting rate onto bagasse treated with ammonium hydroxide ...

To determine grafting rates, the conversion curves were plotted on a log-log diagram (see also Refs. 2 and 4). This plot is shown in Figure 2. The initial portions of the curves are straight lines with a constant slope P = 1.25. The weight increase of the films follows the relationship ... 

The instantaneous grafting rate at 10% weight increase derived from the above results is plotted as a function of dose rate in Figure 3 on a log-log diagram. The plot obeys the following relationship ... 

The grafting rates decrease as the concentration of CuCl2 rises. This effect demonstrates that the inhibitor not only interferes with homopolymerization but also affects the grafting process except perhaps in its initial stages (see Figure 8). 

Fig. 2 Grafting reaction of the silicone-based polymers having P-cyclodextrins as side chains. z=0 and x+y=l for the PMHS homopolymer z=0.75 and x+y = 0.25 for the HMS-301 copolymer. R is either H after incomplete grafting of P-cyclodextrin units, or the pentyl substituent after deactivation of the Si-H by reaction with 1-pentene. The final compound is called PMHS-CD(x) for X % grafting rate...

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