Rheological Properties of Linear and Branched Polyisoprene

@article{citeulike:1120056, abstract = {Viscosity p and first normal stress N1 have been measured as functions of shear rate ’i for solutions of linear, four-arm star, and six-arm star polyisoprenes, all with narrow molecular weight distributions. Concentrations in tetradecane ranged from 0.02 g/ml to 0.33 g/ml; molecular weights ranged from 35 000 to 2 000 000. All measurements were made at 25 O C in a Weissenberg Rheogoniometer. The effects of branching on zero shear viscosity 70, steady state compliance Jeo, the characteristic shear rate (marking the onset of shear rate dependence in p ) 40, and the shape of the p vs. i. master curve were determined. At low concentrations and molecular weights the values of 90 and Jeo were lower for the branched samples, while at high concentrations and molecular weights the reverse became true and substantial enhancements in \~{}0 and Jeo were found. On the other hand, the product pOJeo+o was essentially the same for all samples irrespective of concentration, molecular weight, or branching, and the form of 1 he master curve appeared to be independent of branching. Enhancement factors were determined and compared with results reported by Kraus and Gruver on star-branched polybutadienes. Data on viscosity enhancement for the two polymers reduced to essentially the same curve when correlated in terms of @5’6(@Mb/M,)@, being the volume fraction of polymer, Mb the molecular weight of the branches, and M, the characteristic molecular weight for entanglement in the respective undiluted linear polymers. The form of this correlating parameter was arrived at by considerations on the effect of long branches on macromolecular mobility in entangling systems. The interpretation of enhancement in po and Je0 in relation to the spectrum of relaxation times and their practical effects on p vs 4 behavior are discussed.}, author = {Graessley, W. W. and Masuda, T. and Roovers, J. E. L. and Hadjichristidis, N. }, citeulike-article-id = {1120056}, comment = {星形PIのゼロずりとコンプライアンス}, doi = {http://dx.doi.org/10.1021/ma60049a025}, journal = {Macromolecules}, keywords = {branch, polyisoprene, rheology, solution, star}, month = {January}, number = {1}, pages = {127--141}, posted-at = {2007-02-24 15:02:40}, priority = {2}, publisher = {American Chemical Society}, title = {Rheological Properties of Linear and Branched Polyisoprene}, url = {http://dx.doi.org/10.1021/ma60049a025}, volume = {9}, year = {1976} }

TY - JOUR ID - citeulike:1120056 L3 - citeulike-article-id:1120056 TI - Rheological Properties of Linear and Branched Polyisoprene JF - Macromolecules VL - 9 IS - 1 SP - 127 EP - 141 PB - American Chemical Society N2 - Viscosity p and first normal stress N1 have been measured as functions of shear rate ’i for solutions of linear, four-arm star, and six-arm star polyisoprenes, all with narrow molecular weight distributions. Concentrations in tetradecane ranged from 0.02 g/ml to 0.33 g/ml; molecular weights ranged from 35 000 to 2 000 000. All measurements were made at 25 O C in a Weissenberg Rheogoniometer. The effects of branching on zero shear viscosity 70, steady state compliance Jeo, the characteristic shear rate (marking the onset of shear rate dependence in p ) 40, and the shape of the p vs. i. master curve were determined. At low concentrations and molecular weights the values of 90 and Jeo were lower for the branched samples, while at high concentrations and molecular weights the reverse became true and substantial enhancements in ~0 and Jeo were found. On the other hand, the product pOJeo+o was essentially the same for all samples irrespective of concentration, molecular weight, or branching, and the form of 1 he master curve appeared to be independent of branching. Enhancement factors were determined and compared with results reported by Kraus and Gruver on star-branched polybutadienes. Data on viscosity enhancement for the two polymers reduced to essentially the same curve when correlated in terms of @5’6(@Mb/M,)@, being the volume fraction of polymer, Mb the molecular weight of the branches, and M, the characteristic molecular weight for entanglement in the respective undiluted linear polymers. The form of this correlating parameter was arrived at by considerations on the effect of long branches on macromolecular mobility in entangling systems. The interpretation of enhancement in po and Je0 in relation to the spectrum of relaxation times and their practical effects on p vs 4 behavior are discussed. KW - branch KW - polyisoprene KW - rheology KW - solution KW - star N1 - 星形PIのゼロずりとコンプライアンス AU - Graessley, WW AU - Masuda, T AU - Roovers, JEL AU - Hadjichristidis, N PY - 1976/01// UR - http://dx.doi.org/10.1021/ma60049a025 ER -