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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 9 of 9 for “"Long-chain branching"”.
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Flow Behavior of Sparsely Branched Metallocene-Catalyzed Polyethylenes
… understanding of the influences that sparse long-chain branching has on the rheological and processing behavior of commercial metallocene polyethylene (mPE) resins. In order to clarify these influences, a series of six commercial polyethylenes was investigated. Four of these resins are mPE …
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Linking Rheological and Processing Behavior to Molecular Structure in Sparsely-Branched Polyethylenes Using Constitutive Relationships
… (HDPE) resins, with varying degrees of sparse long chain branching (LCB) content, is used to study the effect of both LCB content and distribution on the rheological and commercial processing response using the Pom-pom constitutive relationship. A flow instability known as ductile failure in …
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Thermorheology and processing of polyethylene blends : macromolecular structure effects
… was studied with emphasis on the effects of long chain branching. First, a linear low-density polyethylene (LL3001.32) was blended with four LDPE's having distinctly different molecular weights. At high LDPE weight fractions, DSC melting thermograms have shown three different polymer phases; …
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Incorporation of Polar Comonomers Into High Density Polyethylene With a Cyclopentadienyl-Amido Titanium Catalyst
… produced by 1 was substantially linear HDPE with long chain branching and that comonomer incorporation reduced the Tc and Tm, probably due to increased short chain branching. 1-TMSO-9-Decene was the most effective comonomer, as it had the highest incorporation rates (8.0 mol%) of all three of the …
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Dilute solution studies of molecular weight distributions of nitrocellulose, modified lignins and PMMA graft polymers
… weights but containing different levels of branching. Variable temperature GPC/LALLS/DV was employed to obtain molecular weight distributions, branching parameters, average chain dimensions and information on the hydrodynamic behavior of these branched systems. Samples containing up to 40% …
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Synthesis of well-defined single and multiphase polymers using various living polymerization methods
… were utilized as model homopolymers exhibiting long chain branching. The methacryloyloxy functionalized PDMS macromonomers were free radically and anionically copolymerized with MMA to yield PMMA-g-PDMS copolymers. The graft copolymers were fractionated and their chemical composition …
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Einfluss der Topologie auf die rheologischen Eigenschaften von Polymeren
Ziel der Arbeit war es, den Einfluss der molekularen Architektur – der sogenannten Molekültopologie – von Polymeren auf deren viskoelastische Eigenschaften zu untersuchen, um ein Verfahren zur Charakterisierung der Langkettenverzweigungen (LKV) abzuleiten.
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Novel Monomer Design for Next-Generation Step-Growth Polymers
… poor mechanical properties. Introduction of long-chain branching (LCB) into PEIs provided a unique comparison between a commercially relevant PEI (Ultem® 1000) and a regioisomer infrequently found in the literature. Thermal stability remained consistent for each regioisomer, and Tgs for the …
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Methode zur Charakterisierung von Langkettenverzweigungen in polydispersen Polymeren
Ziel der Dissertation war es, die Einflüsse von Topologie (d.h. Verzweigungsstruktur) und Molekulargewichtsverteilung langkettenverzweigter Polymere auf deren linear viskoelastische Eigenschaften zu untersuchen. Von diesen Erkenntnissen ausgehend wurde ein Verfahren zur Charakterisierung von …