Rheological study of the influence of Mw and comonomer type on the miscibility of m-LLDPE and LDPE blends

Hameed, Tayyab; Hussein, Ibnelwaleed A.

doi:10.1016/s0032-3861(02)00627-4

Cited by 74 publications

(86 citation statements)

References 45 publications

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“…Low M w m-LLDPE (67 kg/mol) blends with LDPE were miscible at all compositions while the high M w m-LLDPE (108 kg/ mol) blends showed partial miscibility at high LLDPE content and immiscibility at low LLDPE content with the same LDPE. 25 Similar results were observed for low-M w (50 kg/mol) and high-M w (100 kg/mol) ZN-LLDPE blends with LDPE. 28 Branch content of m-LLDPE was also found to have a significant effect on its miscibility with LDPE.…”

supporting

confidence: 77%

“…The hexene-copolymers are used to study the effect of M w at low BC level, whereas, the butenecopolymers were used to investigate the influence of M w at high BC level. Studies 22,25 by the authors showed that comonomer type of m-LLDPE has no influence on miscibility of its blends with HDPE. Hence, the results for hexene and butene m-LLDPE blends could be compared to study the effect of M w at high and low BC level.…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

“…The BC of copolymers was obtained from 13 C NMR as described in a previous publication. 25 The M n , M w and MWD were obtained by Waters 2000 GPC instrument. Trichlorobenzene was used as solvent at 135 C and standard polystyrene samples were utilized for calibration.…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

“…A large number of studies utilizing different techniques were devoted to investigate the phase morphology and characterization of polyolefin blends. These techniques include transmission electron spectroscopy, [8][9][10][11] small angle neutron scattering, [11][12][13] differential scanning calorimetry, 2,5,11,[14][15][16][17][18][19][20][21][22][23] rheology, 3,4,6,7,[16][17][18][24][25][26][27][28][29][30] X-ray diffraction 11,14,31 and more recently thermal fractionation techniques. 33,34 Mechanical characterization of polyolefin blends has also been a subject of interest.…”

mentioning

confidence: 99%

“…They observed that low M w of m-LLDPE enhanced its miscibility with linear HDPE. Recently, the authors have extensively studied the influence of molecular parameters on the miscibility of different polyethylenes [21][22][23][24][25][26][27] using rheological techniques. M w of m-LLDPE 24 and ZN-LLDPE 28 was found to have a strong influence on its miscibility with LDPE.…”

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confidence: 99%

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Melt Miscibility and Mechanical Properties of Metallocene LLDPE blends with HDPE: Influence of Mw of LLDPE

Hameed¹,

Hussein

2006

Polym J

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ABSTRACT:The influence of M w of LLDPE on the rheological, thermal and mechanical properties of m-LLDPE/ HDPE blends of low and high branch content (BC) was studied. Melt rheology of m-LLDPE blended with linear HDPE revealed strong influence of M w on melt miscibility at both branching levels. Low M w m-LLDPE/HDPE blends are suggested to be miscible at all compositions, while viscosity of high M w m-LLDPE/HDPE blends showed negative deviation from log additivity suggesting layered morphology of these blends. The DSC results suggest that compatibility in the solid state is independent of M w and BC. For all blends studied, the HDPE-rich blends were found to contain single crystal populations suggesting high degree of cocrystallization, whereas, m-LLDPE rich phase showed separate crystallization. The melt miscibility and the crystallization of high BC m-LLDPE blends with HDPE are suggested to be controlled by different factors. Small strain mechanical properties of these blends were found to be a strong function of blend compatibility and the specific properties of the blend components.[doi:10.1295/polymj.PJ2005254] KEY WORDS LLDPE/HDPE Blends / Miscibility / Rheology / Mechanical Properties / DSC / Molecular Weight / Polyethylene blends are widely used to improve processing and tailor properties.1-7 However, this enhancement of processing and properties is dictated by phase homogeneity or heterogeneity of these blends in the melt and solid state. A large number of studies utilizing different techniques were devoted to investigate the phase morphology and characterization of polyolefin blends. These techniques include transmission electron spectroscopy, [8][9][10][11] small angle neutron scattering, 11-13 differential scanning calorimetry, 2,5,11,[14][15][16][17][18][19][20][21][22][23] rheology, 3,4,6,7,[16][17][18][24][25][26][27][28][29][30] X-ray diffraction 11,14,31 and more recently thermal fractionation techniques. 33,34 Mechanical characterization of polyolefin blends has also been a subject of interest. 2,[5][6][7][20][21][22][23][30][31][32] Molecular parameters like branch content (BC), branch type, composition distribution, molecular weight (M w ) and molecular weight distribution (MWD) were found to be the key factors affecting the miscibility of polyolefin blends. Hill 9 using transmission electron spectroscopy (TEM) found that M w of linear HDPE had little influence on its miscibility with branched PEs. Alamo et al.12 observed that BC of the branched polyethylene (PE) is the most important parameter controlling the phase behavior of branched and linear PE blends. They reported no effect of M w of branched PE on its miscibility with linear polyethylene for M w $ 100 kg/mol. On the other hand, Tanem and Stori 10 reported strong influence of M w on miscibility of linear and branched PEs. They observed that low M w of m-LLDPE enhanced its miscibility with linear HDPE. Recently, the authors have extensively studied the influence of molecular parameters on the miscibility of different polyethylenes [21][2...

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supporting

confidence: 77%

Section: Materials and Sample Preparationmentioning

confidence: 99%

Section: Materials and Sample Preparationmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Melt Miscibility and Mechanical Properties of Metallocene LLDPE blends with HDPE: Influence of Mw of LLDPE

Hameed¹,

Hussein

2006

Polym J

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Effects of ultrasonic oscillations on processing behavior and mechanical properties of metallocene‐catalyzed linear low‐density polyethylene/low‐density polyethylene blends

Guo

Chen

et al. 2004

J of Applied Polymer Sci

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ABSTRACT:The influences of ultrasonic oscillations on rheological behavior and mechanical properties of metallocene-catalyzed linear low-density polyethylene (mLLDPE)/ low-density polyethylene (LDPE) blends were investigated. The experimental results showed that the presence of ultrasonic oscillations can increase the extrusion productivity of mLLDPE/LDPE blends and decrease their die pressure and melt viscosity during extrusion. Incorporation of LDPE increases the critical shear rate for sharkskin formation of extrudate, crystallinity, and mechanical properties of mLLDPE. The processing behavior and mechanical properties of mLLDPE/LDPE blends were further improved in the presence of ultrasonic oscillations during extrusion.

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Rheological and thermal properties of single‐site polyethylene blends

Chen

Shanks

Amarasinghe

2005

J of Applied Polymer Sci

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Branched polyethylenes, low-density polyethylenes (LDPE1 and LDPE2) or long-chain-branched very low density polyethylenes (VLDPE2), were blended with very low density polyethylenes containing short branches (VLDPE1 and VLDPE3). The rheological and thermal measurements of the pure copolymers and their blends (VLDPE1-LDPE1, VLDPE1-LDPE2, VLDPE1-VLDPE2, and VLDPE2-VLDPE3) were taken by controlled stress rheometry and differential scanning calorimetry, respectively. The shear-thinning effect became stronger with increasing longchain-branched polymer compositions when it was correlated with the flow behavior index, and the extent of shear thinning was different for each blend set. Stronger shear thinning and a linear composition dependence of the zeroshear viscosity were observed for the VLDPE1-LDPE1 and VLDPE1-LDPE2 blends. These blends followed the log additivity rule, and this indicated that they were miscible in the melt at all compositions. In contrast, a deviation from the log additivity rule was observed for the VLDPE1-VLDPE2 blend compositions with 50% or less VLDPE2 and for the VLDPE3-VLDPE2 blends with 50% or more VLDPE2. The thermal properties of the blends were consistent with the rheological properties. VLDPE1-LDPE1 and VLDPE1-LDPE2 showed that these blends were characteristic of a single-component system at all compositions, whereas the phase separation (immiscibility) was detected only for VLDPE1-VLDPE2 blends with 50% or less VLDPE2 and for VLDPE3-VLDPE2 blends with 50% or more VLDPE2. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1549 -1557, 2005

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Rheological study of the influence of Mw and comonomer type on the miscibility of m-LLDPE and LDPE blends

Cited by 74 publications

References 45 publications

Melt Miscibility and Mechanical Properties of Metallocene LLDPE blends with HDPE: Influence of Mw of LLDPE

Melt Miscibility and Mechanical Properties of Metallocene LLDPE blends with HDPE: Influence of Mw of LLDPE

Effects of ultrasonic oscillations on processing behavior and mechanical properties of metallocene‐catalyzed linear low‐density polyethylene/low‐density polyethylene blends

Rheological and thermal properties of single‐site polyethylene blends

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