The retarded recovery of disentangled state by blending HDPE with ultra-high molecular weight polyethylene

Liu, Mingjin; Wang, Yingxiong; Chen, Jin; Luo, Jiaxu; Fu, Qiang; Zhang, Jie

doi:10.1016/j.polymer.2020.122329

Cited by 16 publications

(9 citation statements)

References 52 publications

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“…Sufficiently high sliding rate leads to increasing shear stress linearly, leading to shear-induced disentanglement (Figure ) and enabling the higher chain mobility (Figure ). Besides, the entanglement loss starts earlier at a higher sliding rate due to the fact that polymer chains have less time to slide at a higher relative sliding rate. The loss of entangled chains brings about the obvious orientation (Figure A,B(a)), in agreement with Sliozberg et al Although slower disentangle rate in the RSF process can be observed compared with disentangle process in the SSF process (Figure C), alternative friction at higher frequencies can still maintain a relatively high degree of disentanglement.…”

Section: Resultsmentioning

confidence: 99%

Progressive Molecular Rearrangement and Heat Generation of Amorphous Polyethene Under Sliding Friction: Insight from the United-Atom Molecular Dynamics Simulations

Qiang

et al. 2020

Langmuir

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Frictional heat has been widely used in various polymer-based advanced manufacturing. The fundamental understanding of the thermodynamics of the interfacial friction of polymer bulk materials can help to avoid compromising the process controllability. In this work, we have performed unitedatom molecular dynamics (MD) simulations to reveal the interfacial friction heating mechanism of amorphous polyethene (PE) in both the single sliding friction (SSF) and reciprocating sliding friction (RSF) modes. Different from the traditional view that the plastic deformation was the primary source of heat generation, the RSF process with no apparent plastic deformation in this work shows a better heat generation performance than SSF, where plastic deformation dominated the friction process. Our analysis uncovers that the mechanism of the interfacial friction heating enhancement in RSF can be attributed to the concentrated high-frequency chain motion related to molecular rearrangement, which is not clearly related to the deformation degree.

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Section: Resultsmentioning

confidence: 99%

Progressive Molecular Rearrangement and Heat Generation of Amorphous Polyethene Under Sliding Friction: Insight from the United-Atom Molecular Dynamics Simulations

Qiang

et al. 2020

Langmuir

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“…Meanwhile, regarding better miscibility, the maximum addition threshold of Dis-UHMWPE particles for EPDM reaches 20 wt%, which corresponds well with Cole-Cole curves. In terms of rheology, the maximum addition amount of blending Different from nanoparticles, the molecular chains of UHMWPE are disentangled under the shear modification, and the disentangled chain segments tend to reentangle to equilibrium state in the form of random coil originated from the entropy driven in the molten state [33]. Therefore, we use rheological methods to track the recovery process of entanglement, reflecting the situation of biphasic interfacial interdiffusion.…”

Section: Interfacial Interdiffusionmentioning

confidence: 99%

Metallocene Polyolefins Reinforced by Low-Entanglement UHMWPE through Interfacial Entanglements

Tang

Xing

Xiang

et al. 2022

Advances in Polymer Technology

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By introducing low-entanglement UHMWPE, the mechanical properties of polyolefins are improved to varying degrees. For polypropylene, the lack of interaction between UHMWPE and polypropylene results in an unsatisfactory reinforcement effect, and the disentangled state makes it easier for the particles to form defects driven by a chain explosion. In contrast, regarding polyethylene and elastomer containing ethylene segments, low-entanglement UHMWPE plays a better role in reinforcement. A series of measurements including scanning electron microscopy (SEM), rheological measurements, differential scanning calorimetry (DSC), and mechanical measurement were used to investigate the mechanisms for the different enhancement effects. It originates from interdiffusion and entanglement forming of polyethylene segments across the interface, endowing the material with different aggregated and defect structures. For instance, EPDM possesses a higher optimal dosage of UHMWPE particles reflected in good interfacial interdiffusion with UHMWPE particles, leading to significant optimized mechanical performance.

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“…Extensive research attempts have been devoted to the viscoelastic behavior of UHMWPE filled with additives. − It was reported that suitable fillers can arrest the chain dynamics to an extent that the nonequilibrium melt state with a low degree of entanglement is maintained . Chai et al discovered that chain disentanglement and quicker segment relaxation can be induced in UHMWPE by blending with nanoparticles that are smaller than the tube size of polyethylene (PE) (3.26 nm).…”

Section: Introductionmentioning

confidence: 99%

Influence of Modified Ziegler–Natta Catalyst on the Entanglement Behavior and Properties of Ultrahigh-Molecular-Weight Polyethylene (UHMWPE)

Zhou

Zhang

Zhao

et al. 2022

Ind. Eng. Chem. Res.

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Different dealcoholizing methods and polyhedral oligomeric silsesquioxanes (POSS) were utilized for the modification of Ziegler−Natta catalysts. Their effects on the properties of the catalysts and the synthesized ultrahigh-molecular-weight polyethylene (UHMWPE) were thoroughly studied. It was found that physical dealcoholization of the magnesium chloride−ethanol adducts increased the specific surface area (SSA) of the catalysts more effectively than chemical dealcoholization, expanding the contact area between active centers and ethylene. Thus, better catalytic activity was induced. The sufficient distance between growing chains is the key point in the entanglement degree of UHMWPE. With the load of TiCl 4 , physical dealcoholized catalysts always provide greater spacing between growing chains, decreasing the potential of segment tangling, and that matches the lessentangled state of the synthesized UHMWPE determined by the initial storage modulus by a rotary rheometer. The modification of the catalysts by polyhedral oligomeric silsesquioxanes (POSS) was also studied, and it was discovered that POSS shows little effect on catalytic activity. However, POSS-modified catalysts limited the active centers to a closer range. Coupled with the strong interaction between UHMWPE and POSS particles, UHMWPE with a higher entanglement state were produced. The crystallization behavior and mechanical properties of the obtained UHMWPE were also studied.

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The retarded recovery of disentangled state by blending HDPE with ultra-high molecular weight polyethylene

Cited by 16 publications

References 52 publications

Progressive Molecular Rearrangement and Heat Generation of Amorphous Polyethene Under Sliding Friction: Insight from the United-Atom Molecular Dynamics Simulations

Progressive Molecular Rearrangement and Heat Generation of Amorphous Polyethene Under Sliding Friction: Insight from the United-Atom Molecular Dynamics Simulations

Metallocene Polyolefins Reinforced by Low-Entanglement UHMWPE through Interfacial Entanglements

Influence of Modified Ziegler–Natta Catalyst on the Entanglement Behavior and Properties of Ultrahigh-Molecular-Weight Polyethylene (UHMWPE)

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