Long-chain branching frequency

It can also be expected that any calculations of long chain branching frequency (12,13) will be severely compromised by errors resulting from supermolecular structures. This is because the frequency of long branches resulting from chain transfer to... 

Rudin A (1991) Measurement of long-chain branch frequency in synthetic polymers. In Barth HC, Mays JW (eds) Modern methods of polymer characterization. WUey, New York... 

Fig. 4. Chain-length distribution as a function of long-chain branching frequency for a model polymer with Nn = 1000, Fi = 0.5, and ryr2 = 1.0. The curves are obtained by integrating equation 6 over the entire composition range, — oo < y < -1- oo. For details see Ref 6.

Fig. 5. Chemical composition distribution as a fimction of long-chain branching frequency...

The nonisothermal procedures clearly gives higher productivity and with an appreciably lower long chain branching frequency (5 = 0.42... 

Rokudai and Okada [3] also defined a parameter X., which represented the long-chain branching frequency and attempted to get the correlation between it and MFI as shown in Fig. 9.7. The curves obtained had a scatter for th polymer from the tubular reactor which was no better than that in Fig. 9.5 for versus MFI. Thus, they developed a summation series to predict MFI from weight-average molecular weight and long-chain branching frequency as follows ... 

Figure 9.7 Relationship between long-chain branching frequency and melt flow index (symbols same as in Figs 9.5 and 9.6). (From Ref. 3.)...

Beigzedeh.J. B. P. Soares and T. A. Duever, Combined metallocene catalysts An efficient technique to manipulate long-chain branching frequency of polyethylene. Mocromoi Rapid Commun. (1999) 20, pp. 5541-545... 

Beigzadeh, J. B. P. Soares and A. E. Hamielec, Recipes for synthesizing polyolefins with tailor-made molecular weight, polydispersity index, long-chain branching frequencies, and chemical composition using combined metallocene catalyst systems in a CSTR at steady state./. Appl Polym. Sci (1999) 71, pp. 1753-1770... 

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