ISSN:
1573-8922
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Conclusions 1. The molecular structure indices of low-density polyethylene (LDPE), i.e., the weighted-average (wt.-av.) molecular weight, the number of branch points of long-chain branchings per molecule, and the polydispersity index, were calculated from the data of gel-permeation chromatography, assuming that the Mendelson—Drott hypothesis holds. They show a fairly close correlational relationship to the index of the mechanical characteristics of this melt. 2. The correlation between the highest Newtonian viscosity and the molecular characteristics, taking into account the polydispersity index, is improved if the low-molecular-weight part of the molecular weight distribution MWD (M 〈 800) is neglected. 3. The index of the exponential equation, which determines the dependence of the highest Newtonian viscosity of LDPE on the wt.-av. molecular weight, increases when the influence of the polydispersity is taken into account. 4. Commercial samples of LDPE synthesized under similar technological conditions show a fairly good correlation between the polydispersity and the degree of branching of the molecule. 5. From the highest Newtonian viscosity, the specific relaxation time of the LDPE, and the dependence of the degree of branching of the molecules on the polydispersity of the molecular weights, common for the given technology of the synthesis, it is possible to calculate the molecular structure indices of LDPE with satisfactory accuracy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00859595
