Recoverable deformation and morphology after uniaxial elongation of a polystyrene/linear low density polyethylene blend

Handge, Ulrich A.; Okamoto, K.; Münstedt, Helmut

doi:10.1007/s00397-007-0208-5

Cited by 15 publications

(10 citation statements)

References 40 publications

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“…This result is not surprising, because the faster recovery of polymer blends is caused by additional process occurring in heterogeneous systems besides the molecular retraction, and this was already reported in the literature. [6][7][8][9][10] This additional process is the shape recovery of deformed dispersed droplets driven by the interfacial tension [6] and it accelerates the total retraction of the specimen. Furthermore, the elasticity of the blend characterized by means of l r is higher in comparison with pure PS.…”

Section: Resultsmentioning

confidence: 99%

“…The experimental data for real polymer blends with non-Newtonian behavior are in a qualitative agreement with this model, however, the model overestimates the elasticity of the blends with viscosity ratios far from unity. [8,9] As the model assumes the shape recovery as the only process, the droplet breakups occurring during the recovery can be the reason for this deviation. According to the experimental results presented here in this paper where similar system is studied, this explanation seems to be plausible, because shape recovery and breakup of droplets were observed proceeding simultaneously during recovery.…”

Section: Introductionmentioning

confidence: 99%

“…According to the experimental results presented here in this paper where similar system is studied, this explanation seems to be plausible, because shape recovery and breakup of droplets were observed proceeding simultaneously during recovery. Unfortunately, in these works [6][7][8][9] no quantitative evaluation of the morphology development during the recovery was performed.…”

Section: Introductionmentioning

confidence: 99%

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Shape Recovery Versus Breakup of Deformed Droplets in a Polymer Blend after Uniaxial Extension

Starý¹,

Musialek²,

Münstedt³

2010

Macro Materials & Eng

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The morphology development in a PS/LLDPE 95/5 blend after uniaxial elongation at constant stress is investigated with a special attention on the influence of the temperature on the competition between shape recovery and droplet breakup. The lower the recovery temperature, the finer the morphology obtained, i.e. fibril breakup was preferred against shape recovery. This is due to a stronger retraction of matrix molecules at higher temperatures in early stages of recovery which forces the fibrils to shrink back to less deformed states and thus suppresses the droplet breakup. The elasticity of the blend was found to increase with temperature although the elasticity of pure PS is temperature independent. This is explained as a consequence of the temperature dependence of the morphology development. magnified image

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Shape Recovery Versus Breakup of Deformed Droplets in a Polymer Blend after Uniaxial Extension

Starý¹,

Musialek²,

Münstedt³

2010

Macro Materials & Eng

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“…However, it was shown that the samples showing this phase behavior in the solid state [16] did not show it in the melt state, as the samples behaved like normal linear low density polyethylenes (LLDPEs), being only special because of their higher flow activation energy E a , which is the consequence of the side-chain content s c of the comonomer [19,20]. Phase separation in the melt is usually visible by traces of the interfacial tension [21] and different temperature dependencies of the individual blend components and the interfacial processes [22,23]. Hence, if other techniques don't show any trace, e.g., because of too low differences in the electron density in X-ray scattering, rheological behavior can provide a valuable aid to the characterization of phase separation.…”

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confidence: 99%

Evidence of intra-chain phase separation in molten short-chain branched polyethylene

Stadler¹

2011

Express Polym. Lett.

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Abstract. Intramolecular phase separation is usually associated with block-copolymers, but the same phenomenon is also obtainable by random-copolymers. In this article, evidence of intramolecular phase separation is reported for a linear octadecene-ethene copolymer, which shows an evolving 'yield point' at a long time and low frequency. This is attributed to a partial phase separation of the long short-chain branches. In creep recovery, this behavior is evident as increasing elastic steady-state creep recovery compliance J e 0 . In contrast to 'normal' block-copolymers, this special polymer has an increase in phase separation with temperature, which is caused by the chemical composition and the short chain segments in the side chain domain, leading to a high surface fraction. Vol.5, No.4 (2011) 327-341 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2011 * Corresponding author, e-mail: fjstadler@jbnu.ac.kr © BME-PT length in their paper, as it cannot be determined due to the synthesis method. Such block-copolymers are usually thermorheologically complex [9,14,15]. The group of Bates [9,10], for example, found that below the order-disorder transition temperature, i.e., in the ordered state, the sample behaves like a gel and thermorheologically simple, while in the disordered state, a clear thermorheological complexity is found. The higher the temperature, the less pronounced the long-term relaxation process and, thus, the more similar is the data to a single-phase polymer melt. Recently, it was also proven that pure ethylene-/!-olefin copolymers with very long comonomers (C26) can be phase separating in the solid state, if their comonomer content is sufficiently high [16]. This effect is different from the previous cases, because it only involves one type of chain and, furthermore, occurs on random copolymers. Hence, it is an effect that occurs only on a short length scale, as shown by the fact that the length of the comonomers used were 18 and 26 carbons. Thus, the second phase has to encompass only the maximum of 24 terminal carbons; realistically, 16-20 carbons. This effect had a small trace in X-ray diffraction, which points to a weak side chain crystallization [17,18]. However, it was shown that the samples showing this phase behavior in the solid state [16] did not show it in the melt state, as the samples behaved like normal linear low density polyethylenes (LLDPEs), being only special because of their higher flow activation energy E a , which is the consequence of the side-chain content s c of the comonomer [19,20]. Phase separation in the melt is usually visible by traces of the interfacial tension [21] and different temperature dependencies of the individual blend components and the interfacial processes [22,23]. Hence, if other techniques don't show any trace, e.g., because of too low differences in the electron density in X-ray scattering, rheological behavior can provide a valuable aid to the characterization of phase separation. Recently, molecular dynamics studies revea...

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“…Thus, mixing LLDPE with a yield-and/or creep-resistant polymer is still an interesting area of materials research. Handge et al [32] and Liu et al [33] prepared polystyrene (PS)/ LLDPE blends, while Zhang and coworkers [34,35] utilized different kinds of organic compatibilizers to enhance the interface adhesion in polyethylene terephthalate (PET)/LLDPE blends. Ismail et al [36] investigated the processability and miscibility of LLDPE/ polyvinylalcohol (PVA) systems at different blend ratios, finding that the difference in polarity caused very low miscibility of the two components.…”

Section: Introductionmentioning

confidence: 99%

Linear low density polyethylene/cycloolefin copolymer blends

Dorigato¹,

Pegoretti²,

Fambri³

et al. 2011

Express Polym. Lett.

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Abstract. Linear low density polyethylene (LLDPE) was melt compounded with various amounts of a cycloolefin copolymer (COC). Scanning and transmission electron microscopy evidenced, at qualitative level, some interfacial adhesion between LLDPE and COC. Another indication of interactions between the components was the increase of crystallinity degree with rising COC content and the enhancement of COC glass transition temperature with the LLDPE fraction. In order to explain this behaviour, the incorporation of ethylene segments of COC into the LLDPE crystalline phase, leading to an increased number of norbornene units in the remaining COC component undergoing the glass transition, was hypothesized. The thermo-oxidative degradation stability of LLDPE was substantially enhanced by COC introduction for filler contents higher than 20 wt%, especially when an oxidative atmosphere was considered. An increasing fraction of COC in the blends was responsible for an enhancement of the elastic modulus and of a decrease in the strain at break, while tensile strength passed through a minimum, in agreement with the model predictions based on the equivalent box model and equations provided by the percolation theory. The introduction of a rising COC amount in the blends increased the maximum load sustained by the samples in impact tests, but decreased the blend ductility. Concurrently, a significant reduction of the creep compliance of LLDPE was observed for COC fractions higher than 20 wt%.

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Recoverable deformation and morphology after uniaxial elongation of a polystyrene/linear low density polyethylene blend

Cited by 15 publications

References 40 publications

Shape Recovery Versus Breakup of Deformed Droplets in a Polymer Blend after Uniaxial Extension

Shape Recovery Versus Breakup of Deformed Droplets in a Polymer Blend after Uniaxial Extension

Evidence of intra-chain phase separation in molten short-chain branched polyethylene

Linear low density polyethylene/cycloolefin copolymer blends

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