Linear low density polyethylenes and their blends: Part 3. Extensional flow of LLDPE's

Schlund, B.; Utracki, L. A.

doi:10.1002/pen.760270511

Cited by 46 publications

(18 citation statements)

References 44 publications

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“…24,25 Schlund and Utracki pointed out the important phenomenon that the increased molding time induces a stronger strain-hardening property in LLDPE. 11 It was interpreted that the entanglement increases with time. The origin of the phenomenon is rooted in the fact that some of the PEs themselves are not homogeneous because of using no single phase catalyst or two-step polymerization.…”

Section: Introductionmentioning

confidence: 99%

Elongational viscosity for miscible and immiscible polymer blends. II. Blends with a small amount of UHMW polymer

Takahashi

Takimoto

Koyama

1999

J. Appl. Polym. Sci.

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ABSTRACT:The effect of miscibility on elongational viscosity of polymer blends was investigated in homogeneous, miscible, and immiscible states by the blend of 1.5 wt % of ultrahigh-molecular-weight (UHMW) polymer. The matrix polymer was either poly-(methyl methacrylate) (PMMA), or poly(acrylonitrile-co-styrene) (AS) that has a comparable elongational viscosity value. The homogeneous blend consisted of 98.5 wt % of PMMA and 1.5 wt % of UHMW-PMMA. The miscible blend was composed of AS and UHMW-PMMA at the same ratio. The immiscible blend was a combination of AS and UHMW-polystyrene (PS) at the same ratio. The strain-hardening behavior of the different blends were compared with that of pure PMMA. It was demonstrated that 1.5 wt % of UHMW induces a strong strain-hardening property in the homogeneous and miscible blends but was hardly changed in the immiscible blend. The optical microscope observation of the immiscible blend suggested that the UHMW domains were stretched, but that the degree of domain deformation was less than a given elongational strain. It was concluded that the strain-hardening property is strongly affected by the miscibility of UHMW chain and matrix. The strong strain-hardening property is caused by the deformation of the UHMW polymer. UHMW chains are stretched when they are entangled with surrounding polymers. However, UHMW chains in an immiscible state are not so deformed because of viscosity difference and no entanglements between domain and matrix. A smaller degree of UHMW chain deformation in immiscible state results in weaker strain-hardening property.

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Section: Introductionmentioning

confidence: 99%

Elongational viscosity for miscible and immiscible polymer blends. II. Blends with a small amount of UHMW polymer

Takahashi

Takimoto

Koyama

1999

J. Appl. Polym. Sci.

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“…A higher value of tensile stress at a given strain rate indicates higher melt strength. Previous research [4] has shown that the initial slope of the stress/strain curve for LLDPE resins correlates with the breadth of the resins' molecular weight distribution (MWD) and that LLDPE shows no strain hardening, even for HMW and broad MWD. Strain hardening is only seen in LDPE as a result of long chain branching.…”

Section: Rheologymentioning

confidence: 99%

Lldpe Resins for High Output Blown Film Extrusion

Cooke

Koyich

1991

Journal of Plastic Film & Sheeting

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“…It is very difficult to predict nonlinear melt viscoelasticity of miscible and immiscible blends from their linear viscoelasticity, because polymer behavior and phase structures are dramatically changed by large deformation. Nonlinear melt viscoelasticity has been most frequently investigated under uniaxial elongational deformation 7–20. Elongational rheology studies of polymer blends are classified into two groups.…”

Section: Introductionmentioning

confidence: 99%

“…Elongational rheology studies of polymer blends are classified into two groups. One is acrylonitrile–butadiene–styrene (ABS) polymers,7–12 and the other is polyethylene‐based blends 13–20…”

Section: Introductionmentioning

confidence: 99%

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Elongational viscosity for miscible and immiscible polymer blends. I. PMMA and AS with similar elongational viscosity

Takahashi

Takimoto

Koyama

1999

J. Appl. Polym. Sci.

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ABSTRACT:The effects of miscibility and blend ratio on uniaxial elongational viscosity of polymer blends were studied by preparing miscible and immiscible samples at the same composition by using poly(methyl methacrylate) (PMMA) and poly(acrylonitrileco-styrene) (AS). Miscible polymer blend samples for the elongational viscosity measurement were prepared by using three steps: solvent blends, cast film, and hot press. A phase diagram of blend samples was made by visual observation of cloudiness. Immiscible blend samples were prepared by maintaining the prepared miscible samples at 200°C, which is higher than cloud points using a LCST (lower critical solution temperature) phase diagram. The phase structure of immiscible blends was observed by an optical microscope. The elongational viscosity of all samples was measured at 145°C, which is lower than the cloud-point temperature at all blend ratios. The elongational viscosity of PMMA and AS was similar to each other. The strain-hardening property of miscible blends in the elongational viscosity was only slightly influenced by the blend ratio, and this was also the case with immiscible blends. The strain-hardening property was only slightly influenced, whether it was miscible or immiscible at each blend ratio. Polydispersity in molecular weight for blend samples was not changed by GPC (gel permeation chromatography) analysis. Almost no change in the polydispersity of the molecular weight for blends and the similarity of elongational viscosity between PMMA and AS resulted in little influence of the blend ratio and miscibility on the strainhardening property.

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Linear low density polyethylenes and their blends: Part 3. Extensional flow of LLDPE's

Cited by 46 publications

References 44 publications

Elongational viscosity for miscible and immiscible polymer blends. II. Blends with a small amount of UHMW polymer

Elongational viscosity for miscible and immiscible polymer blends. II. Blends with a small amount of UHMW polymer

Lldpe Resins for High Output Blown Film Extrusion

Elongational viscosity for miscible and immiscible polymer blends. I. PMMA and AS with similar elongational viscosity

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