摘要:
Polymer fractions such as polyethylene fractions can be produced that have a PDI less than about 2.3 and a Mw greater than about 1,000,000 g/mol, 3,000,000 g/mol, or 6,000,000 g/mol. Such polyethylene fractions are separated from a UHMWPE parent polymer by first dissolving the parent polymer in a relatively good solvent. The conditions employed for such dissolution are selected to reduce the degradation of the parent polymer. The resulting parent solution is transported into a fractionation column in which a support is disposed. The fractionation column is thereafter operated at conditions effective to form a precipitate on the support comprising the desired polyethylene fraction. The polyethylene fraction may then be recovered from the fractionation column by repeatedly displacing a solvent/non-solvent mixture into the column to dissolve the polyethylene fraction. The relative concentrations of the solvent and the non-solvent are based on a solvent gradient profile of the polyethylene parent polymer.
摘要:
Polymer fractions such as polyethylene fractions can be produced that have a PDI less than about 2.3 and a Mw greater than about 1,000,000 g/mol, 3,000,000 g/mol, or 6,000,000 g/mol. Such polyethylene fractions are separated from a UHMWPE parent polymer by first dissolving the parent polymer in a relatively good solvent. The conditions employed for such dissolution are selected to reduce the degradation of the parent polymer. The resulting parent solution is transported into a fractionation column in which a support is disposed. The fractionation column is thereafter operated at conditions effective to form a precipitate on the support comprising the desired polyethylene fraction. The polyethylene fraction may then be recovered from the fractionation column by repeatedly displacing a solvent/non-solvent mixture into the column to dissolve the polyethylene fraction. The relative concentrations of the solvent and the non-solvent are based on a solvent gradient profile of the polyethylene parent polymer.
摘要:
An analytical method comprising performing a first fractionation of a polymer sample based on differences in crystallizability to provide a first set of sample fractions, performing a first analysis on the first set of sample fractions, performing a second fractionation of the first set of sample fractions to produce a second set of sample fractions, performing a second analysis on the second set of sample fractions, and synchronizing the first fractionation and second fractionation to provide about concurrent analysis of the polymer sample.
摘要:
Polymer fractions such as polyethylene fractions can be produced that have a PDI less than about 2.3 and a Mw greater than about 1,000,000 g/mol, 3,000,000 g/mol, or 6,000,000 g/mol. Such polyethylene fractions are separated from a UHMWPE parent polymer by first dissolving the parent polymer in a relatively good solvent. The conditions employed for such dissolution are selected to reduce the degradation of the parent polymer. The resulting parent solution is transported into a fractionation column in which a support is disposed. The fractionation column is thereafter operated at conditions effective to form a precipitate on the support comprising the desired polyethylene fraction. The polyethylene fraction may then be recovered from the fractionation column by repeatedly displacing a solvent/non-solvent mixture into the column to dissolve the polyethylene fraction. The relative concentrations of the solvent and the non-solvent are based on a solvent gradient profile of the polyethylene parent polymer.
摘要:
Polymer fractions such as polyethylene fractions can be produced that have a PDI less than about 2.3 and a Mw greater than about 1,000,000 g/mol, 3,000,000 g/mol, or 6,000,000 g/mol. Such polyethylene fractions are separated from a UHMWPE parent polymer by first dissolving the parent polymer in a relatively good solvent. The conditions employed for such dissolution are selected to reduce the degradation of the parent polymer. The resulting parent solution is transported into a fractionation column in which a support is disposed. The fractionation column is thereafter operated at conditions effective to form a precipitate on the support comprising the desired polyethylene fraction. The polyethylene fraction may then be recovered from the fractionation column by repeatedly displacing a solvent/non-solvent mixture into the column to dissolve the polyethylene fraction. The relative concentrations of the solvent and the non-solvent are based on a solvent gradient profile of the polyethylene parent polymer.
摘要:
A composition comprising a polyethylene wherein the composition is enriched in polymer molecules having topological variations by an enrichment factor ω and wherein the composition displays a long chain branching frequency of greater than about 0.5 long chain branches per 1000 total carbon atoms. A composition comprising an isolated Ziegler-catalyzed polyethylene having a long chain branching frequency of greater than about 0.5 long chain branches per 1000 total carbon atoms at the high molecular weight end.
摘要:
Catalyst compositions containing N,N-bis[2-hydroxidebenzyl]amine transition metal compounds are disclosed. Methods for making these transition metal compounds and for using such compounds in catalyst compositions for the polymerization or oligomerization of alpha olefins also are provided.
摘要:
Methods of controlling polymerization reactions using a synergistic amount of hydrogen and an organozinc compound are disclosed. The resulting polymers have lower molecular weights and higher melt flow indices.
摘要:
The present invention provides polymerization catalyst compositions employing half-metallocene compounds with a heteroatom-containing ligand bound to the transition metal. Methods for making these hybrid metallocene compounds and for using such compounds in catalyst compositions for the polymerization of olefins also are provided.
摘要:
The present invention provides polymerization catalyst compositions employing half-metallocene compounds with a heteroatom-containing ligand bound to the transition metal. Methods for making these hybrid metallocene compounds and for using such compounds in catalyst compositions for the polymerization of olefins also are provided.