Ultra-broad molecular weight distribution effects on viscoelastic properties of linear multimodal PE

Szántó, Levente; Feng, Y.; Zhong, Fan; Hees, Timo; Ruymbeke, Evelyne Van; Mülhaupt, Rolf; Friedrich, Christian

doi:10.1122/1.5109481

Cited by 14 publications

(7 citation statements)

References 64 publications

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“…Due to the comparatively low viscosity owing to the large amount of low-molecular-weight HDPE in the RBs, they could be easily blended with high-flow olefinic copolymers and thermoplastic elastomers by melt compounding. 31 Going beyond the scope of all-PE composites 6,28,29 prepared by melt compounding RBs with HDPE, nanophase-separated UHMWPE/HDPE wax RB additives were exploited as reinforcing agents for unmodified isotactic polypropylene (iPP) and ethylene-based copolymers. The thermoplastic ethylene-1-octene copolymer (Infuse 9007; OBC) as a thermoplastic elastomer and the ethylene-methacrylic acid Zn ionomer (Surlyn 1705-1) as an engineering plastic were selected as promising matrix materials owing to their high ethylene content.…”

Section: Resultsmentioning

confidence: 99%

Self-Reinforcement via 1D Nanostructure Formation during Melt Blending of Thermoplastics and Thermoplastic Elastomers with Nanophase-Separated UHMWPE/HDPE Wax Reactor Blends

Hees

Schirmeister

Pfohl

et al. 2021

ACS Appl. Polym. Mater.

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Adding inorganic fillers like glass or carbon fibers is common practice for reinforcing engineering thermoplastics to expand their range of applications in lightweight construction. Albeit the advantages of traditional polymer composites are obvious, the quest for sustainable development and a circular economy is driving the development of recyclable all-polymer composites with a low carbon footprint. Melt blending of commodity high-density polyethylene (HDPE) with reactor blends (RB) comprising nanophase-separated ultrahigh-molecular-weight polyethylene (UHMWPE) substantially improved the toughness/stiffness/strength balance of polyethylene (PE). During processing, the flow-induced formation of nanofiber-like extended-chain UHMWPE one-dimensional (1D) nanostructures accounted for efficient HDPE reinforcement. Herein, we expanded this concept of self-reinforcement and all-polymer composite formation to other thermoplastics and thermoplastic elastomers. Nanophase-separated UHMWPE/HDPE wax reactor blends with ultrabroad bimodal molar distribution served as an additive for melt compounding and injection molding of isotactic polypropylene (iPP), olefin block copolymers (OBC), and a thermoplastic ionomer (Surlyn). Microscopic imaging and evaluation of mechanical properties confirmed the in situ formation of fiberlike UHMWPE 1D nanostructures that efficiently reinforced these thermoplastics and thermoplastic elastomers. The resulting all-polymer composites were a drop-in solution for injection molding of olefinic thermoplastics with unprecedented mechanical properties enabled by the synergy of the characteristics of the matrix material in combination with ultrastrong UHMWPE 1D nanostructures.

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Section: Resultsmentioning

confidence: 99%

Self-Reinforcement via 1D Nanostructure Formation during Melt Blending of Thermoplastics and Thermoplastic Elastomers with Nanophase-Separated UHMWPE/HDPE Wax Reactor Blends

Hees

Schirmeister

Pfohl

et al. 2021

ACS Appl. Polym. Mater.

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“…van Meerveld [ 57 ] has presented a model based on the models of Likhtman and McLeish, [ 58 ] which has shown that the zero‐shear viscosity is a function of entanglement MW and monomeric friction factor. Also, Szántó et al [ 59 ] have proposed a model for the zero‐shear viscosity as a function of M w , M w / M n , and M z / M w . Furthermore, the low MW fraction (oligomer, waxy molecules) in the HDPE resin has the lubricating function and slides the high MW chains, effectively reducing the melt's viscosity.…”

Section: Resultsmentioning

confidence: 99%

Experimental study on the effect of molecular weight and chemical composition distribution on the mechanical response of high‐density polyethylene

Jani¹,

Sepahi²,

Afzali³

et al. 2022

Polymer Engineering & Sci

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This article aims to appraise the effect of microstructure comprising molecular weight distribution and chemical composition distribution on the mechanical properties of high-density polyethylene (HDPE). HDPE resins were synthesized using several titanium-magnesium-supported Ziegler-Natta catalysts in the industrial gas phase reactor under the same polymerization condition. Gel permeation chromatography and crystallization elution fractionation (CEF) were conducted on the resins to characterize the molecular weight and comonomer distribution. Crystallization, thermal and rheological behavior were evaluated following differential scanning calorimetry, polarization light microscopy, and rheometric mechanical spectrometry. The resins with higher soluble fraction in trichlorobenzene below 80 C (highly branched low molecular weight chains) exhibited longer crystallization time based on the crystallization kinetic obtained from the Avrami model. Rheological determination of the molecular weight between entanglements (M e ) and the average lamella thickness based on the Gibbs-Thomson equation revealed that the entanglement density and impact strength decreased, and the average lamella thickness increased with an increase in the ratio of CEF eluted fraction below 80 C to the crystallizable fraction in the range of 80-90 C.

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“…The properties of HDPE are a function of molecular weight and molecular weight distribution (MWD), and mechanical properties are improved with higher molecular weights. A broader MWD promotes processability and impact resistance of polyethylene and narrower MWD leads to higher resistance to environmental stress‐cracking and superior toughness [18,19] . The modification of polyethylene properties can be achieved by copolymerizing ethylene with polar comonomers.…”

Section: Introductionmentioning

confidence: 99%

“…A broader MWD promotes processability and impact resistance of polyethylene and narrower MWD leads to higher resistance to environmental stress-cracking and superior toughness. [18,19] The modification of polyethylene properties can be achieved by copolymerizing ethylene with polar comonomers. Functionalizing polyethylene via ethylene copolymerization with polar comonomers offers improved toughness, adhesion, rheological characteristics, and printability.…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in Transition Metal‐Based Catalysts for Ethylene Copolymerization with Polar Comonomer

Khan

Mazhar

Shehzad

et al. 2023

The Chemical Record

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The synthesis of polar functionalized polyolefin (PFP) offers improvement in mixing properties, polymer surface, and rheological properties with the potential of upgraded polyolefins for modern and ingenious applications. The synthesis of PFP from metal-based catalyzed olefin (non-polar in nature) copolymerization with polar comonomers embodies energy-efficient, atomefficient, and apparently an upfront methodology. Despite their outstanding success during conventional polymerization of olefin, 3 rd and 4 th group (early transition metal)-based catalysts, owing to their electrophilic nature, face challenges mainly due to Lewis basic sites of the polar monomers. On the contrary, late transition metal-based catalysts have also made progress, in recent years, for PFP synthesis. The recent past has also witnessed several advancements in the development of dominating palladium-based catalysts while their lower resistance towards ligand functional groups has limited the practical application of abundant and cheaper nickel-based catalysts. However, the relentless efforts of the scientific community, during the past half-decade, have indicated rigorous progress in the development of nickel-based catalysts for PFP synthesis. In this review, we have abridged the recent research trends in both early as well as late transition metal-based catalyst development. Furthermore, we have highlighted the role of transition metalbased catalysts in influencing the polymer properties.

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Ultra-broad molecular weight distribution effects on viscoelastic properties of linear multimodal PE

Cited by 14 publications

References 64 publications

Self-Reinforcement via 1D Nanostructure Formation during Melt Blending of Thermoplastics and Thermoplastic Elastomers with Nanophase-Separated UHMWPE/HDPE Wax Reactor Blends

Self-Reinforcement via 1D Nanostructure Formation during Melt Blending of Thermoplastics and Thermoplastic Elastomers with Nanophase-Separated UHMWPE/HDPE Wax Reactor Blends

Experimental study on the effect of molecular weight and chemical composition distribution on the mechanical response of high‐density polyethylene

Recent Advances in Transition Metal‐Based Catalysts for Ethylene Copolymerization with Polar Comonomer

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