Structural determination of ethylene-propylene-diene rubber (EPDM) containing high degree of controlled long-chain branching

2009 ◽  
Vol 113 (5) ◽  
pp. 2962-2972 ◽  
Author(s):  
Susanta Mitra ◽  
Mikkel Jørgensen ◽  
Walther Batsberg Pedersen ◽  
Kristoffer Almdal ◽  
Debasish Banerjee
Keyword(s):  
Structural Determination ◽  
Chain Branching ◽  
Long Chain Branching ◽  
Ethylene Propylene ◽  
Ethylene Propylene Diene Rubber ◽  
High Degree ◽  
Diene Rubber ◽  
Long Chain

SEC-MALS method for the determination of long-chain branching and long-chain branching distribution in polyethylene

Polymer ◽  
2005 ◽  
Vol 46 (14) ◽  
pp. 5165-5182 ◽  
Author(s):  
Youlu Yu ◽  
Paul J. DesLauriers ◽  
David C. Rohlfing
Keyword(s):  
Chain Branching ◽  
Long Chain Branching ◽  
Long Chain

Estimation of Long-Chain Branching in Ethylene-Propylene Terpolymers from Infinite-Dilution Viscoelastic Properties

1975 ◽  
Vol 48 (5) ◽  
pp. 1035-1043
Author(s):  
Y. Mitsuda ◽  
J. L. Schrag ◽  
J. D. Ferry
Keyword(s):  
Molecular Weight ◽  
Infinite Dilution ◽  
Relaxation Times ◽  
Branch Points ◽  
Chain Branching ◽  
Long Chain Branching ◽  
Shear Moduli ◽  
Comb Polymers ◽  
Ethylene Propylene ◽  
Long Chain

Abstract A method is outlined for estimation of small degrees of long-chain branching in polymers with moderately narrow molecular weight distribution (Mw/Mn<1.4). The storage and loss shear moduli, G′ and G″, are measured in dilute solution by the Birnboim-Schrag multiple-lumped resonator and extrapolated to infinite dilution, choosing a suitable solvent viscosity and frequency range such that the data lie in the terminal zone where G′ and G″ are proportional to the second and first powers of frequency, respectively. The intrinsic reduced steady-state shear compliance is determined from these data and corrected for moderate molecular weight heterogeneity (assuming a Gaussian distribution) from knowledge ofMw/Mn and the Mark-Houwink exponent a. The resulting value of S2/S12 (where S1=∑ τp/τ1, S2=∑ (τp/τ1)2, the τp's being the relaxation times and τ1 the longest one) is compared with values calculated by the Zimm-Kilb theory as evaluated by Osaki for comb polymers of regular geometry and different numbers of branch points. The method has been illustrated by measurements on four ethylene-propylene copolymers. One containing no termonomer and one containing a saturated termonomer appeared to be linear; two containing unsaturated termonomers showed small degrees of branching. The method appears to be promising for detecting from one to four branch points per molecule.

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