Long-chain branched polymers

We can create crosslinks during chain growth polymerization by copolymerizing dienes with vinyl monomers. When the two vinyl functions of the diene are incorporated into separate chains, a crosslink is formed. This process is shown in Fig. 2.18. When we use a low concentration of dienes, we produce a long chain branched polymer, while high concentrations of dienes create a highly crosslinked polymer network... 

SYNTHETIC STRATEGIES FOR LONG-CHAIN BRANCHED POLYMERS... 

Repetition of this step allows the metal to migrate down the polymer chain, giving rise to long-chain branched polymers.124 These systems are now being developed by industry. 

Tobita H (2003) Bimodal molecular weight distribution formed in emulsion polymerization with long-chain branching. Polym React Eng 11 855 BarabasiA-L, Albert R (1999) Science 286 509... 

The characterization of star-branched polymers has been performed using triple detection because it was not obvious, in the beginning of this study, that universal calibration could be applied to star-branched polymers. In fact, the GPC software used handles experimental data as a double dual detection, GPC-viscometry and GPC-LALLS. Experimentally, it has been found that excellent agreement between results from these two sets of data can be obtained. GPC-viscometry uses a universal calibration curve and GPC-LALLS is free of any molecular weight calibration curve. Therefore, the universal calibration works well with very long chain branched polymers, even with a very particular... 

The secondary use of viscometric detection is for the determination of long-chain branching. At the same molecular weight, a long-chain branched polymer has a more compact molecular structure than the linear one consequently, it also has a smaller intrinsic viscosity. Therefore, it is eluted at a higher elution volume with a linear polymer of smaller molecular weight. That means that at a given elution volume, there is a mixture of... 

Wood-Adams, P. Dealy, J.M. deGroot, A.W. Redwine, O.D. Effect of molecular structure on the linear viscoelastic behavior of polyethylene. Macromolecules 2000, 33 (20), 7489-7499. Trinkle, S. Friedrich, C. Van Gurp-Palmen plot a way to characterize polydispersity of linear polymers. Rheol. Acta 2001, 40 (4), 322-328. Trinkle, S. Walter, P. Friedrich, C. Van Gurp-Palmen plot. II. Classification of long chain branched polymers by their topology. Rheol. Acta 2002, 41 (1-2), 103-113. 

Bonchev, D., Markel, E.J. and Dekmezian, A.H. (2005) Long chain branch polymer chain dimensions application of topology to the Zimm-Stockmayer model. Polymer, 43, 203-222. 

Coupling reactions of polybutadlenyllithium (B ) with chloro-s1lanes are well known and well established(10) and are used for the production of controlled long-chain branched polymers.(il)... 

Small, P. A. "Long Chain Branching Polymers" Springer-Verlag New York, 1975. 

Baig, C., Alexiadis, O., and Mavrantzas, V. G. 2010. Advanced Monte Carlo algorithm for the atomistic simulation of short- and long-chain branched polymers Implementation for model h-shaped, aSaaS multiarm (pom-pom), and short-chain branched polyethylene melts. Macromolecules, 43(2) 986-1002. 

The multidimensional distributions in hb polymers - that is, molar mass and DB-require the use of multidimensional separation techniques. For example, two-dimensional liquid chromatc raphy (2D-LC) [156] can provide simultaneous information on both molar mass and structural characteristics such as topol<, by combining SEC and interaction chromatography into one measurement. These investigations were conducted intensively for the separation of stars or long-chain branched polymers from linear analogs [157-160], and demonstrated the great potential of 2D-LC separations. Until now, the apphcation of 2D-LC has been... 

Correlations of the type described in the preceding paragraph are limited to linear hompolymers and have no validity for long-chain branched polymers such as low-density polyethylene. 

Figure 4 shows the square of the molecular stress function, p, as a function of the average deformation ( ) for linear and long-chain branched polymer melts and for crosslinked rubbers (NR, PDMS). It is clear from Figure 4 that the amount of molecular stress which can be induced in linear macromolecules by deformation in the melt state, is... 

Brant P, Canich JAM, Dias AJ, Bamberger RL, Licciardi GF, Henrichs PM, Exxon Oiemicals (1993) Long chain branched polymers and a process to make long chain branched polymers. International Patent WO 94/07930... 

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