Crystal morphology and corresponding physical properties of nascent ultra-high molecular weight polyethylene powder with short-branched chains

Li, Zhi; Ye, Chunlin; Feng, Lingying; Xia, Jincheng; Zhang, Letian; Zhao, Wenjing; Hu, Yilun

doi:10.1016/j.polymer.2019.121758

Cited by 12 publications

(5 citation statements)

References 36 publications

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“…According to thermodynamic theory, the Tm o the crystal increases as the lamellar thickness increases. Therefore, the quantitativ relationship between the lamellar thickness and the melting point of the polymer can b described in the Thompson-Gibbs equation [43][44][45]: DSC tests were performed to further investigate the difference in the crystalline fraction between less-entangled and well-entangled samples, as shown in Figure 2. Melting points (T m ) obtained from DSC are listed in Table 1.…”

Section: Crystallizationmentioning

confidence: 99%

“…According to thermodynamic theory, the T m of the crystal increases as the lamellar thickness increases. Therefore, the quantitative relationship between the lamellar thickness and the melting point of the polymer can be described in the Thompson-Gibbs equation [43][44][45]:…”

Section: Crystallizationmentioning

confidence: 99%

“…where l, Tm, Tm 0 , σe and ΔH0 are the thickness of the crystalline lamella, melting poin the polymer, equilibrium melting point of the polymer, surface free energy, and melt enthalpy of crystal region, respectively. Usually, Tm 0 , σe and ΔH0 take values of 418.7 K × 10 −3 J • m -2 and 289 × 10 6 J • m -3 for PE, respectively [31,45]. exact values, please refer to Table 1.…”

Section: Crystallizationmentioning

confidence: 99%

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Chain Dynamics of Partially Disentangled UHMWPE around Melting Point Characterized by 1H Low-Field Solid-State NMR

et al. 2023

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Melts of ultrahigh molecular weight polyethylene (UHMWPE) entangled significantly, suffering processing difficulty. In this work, we prepared partially disentangled UHMWPE by freeze-extracting, exploring the corresponding enchantment of chain mobility. Fully refocused 1H free induction decay (FID) was used to capture the difference in chain segmental mobility during the melting of UHMWPE with different degrees of entanglement by low-field solid-state NMR. The longer the polyethylene (PE) chain is in a less-entangled state, the harder the process of merging into mobile parts after detaching from crystalline lamella during melting. 1H double quantum (DQ) NMR was further used to obtain information caused by residual dipolar interaction. Before melting, the DQ peak appeared earlier in intramolecular-nucleated PE than in intermolecular-nucleated PE because of the strong constraints of crystals in the former one. During melting, less-entangled UHMWPE could keep disentangled while less-entangled high density polyethylene (HDPE) could not. Unfortunately, no noticeable difference was found in DQ experiments between PE melts with different degrees of entanglement after melting. It was ascribed to the small contribution of entanglements compared with total residual dipolar interaction in melts. Overall, less-entangled UHMWPE could reserve its disentangled state around the melting point long enough to achieve a better way of processing.

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Section: Crystallizationmentioning

confidence: 99%

Section: Crystallizationmentioning

confidence: 99%

Section: Crystallizationmentioning

confidence: 99%

See 1 more Smart Citation

Chain Dynamics of Partially Disentangled UHMWPE around Melting Point Characterized by 1H Low-Field Solid-State NMR

et al. 2023

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“…With the development of high-performance PE products, it had been found experimentally that short-chain branches (SCBs) had a significant impact on the properties of materials as well. [14][15][16][17] Li et al 18 worked on UHMWPE with a high degree of SCBs. Based on a series of characterization results, it is revealed that SCBs led to a decrease in the entanglement density and brought a significant increase in the processing performance and mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the influential mechanism of short-chain branching on the crystallization of trimodal polyethylene by molecular dynamics simulation

Cai¹,

He²,

Liu³

et al. 2023

Phys. Chem. Chem. Phys.

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“…For example, Fu et al 9 found that the crystallinity of UHMWPE is positively correlated with the yield strength. The crystallization behavior of UHMWPE primary particles with low entanglement degree is different from that of conventional UHMWPE, and thus they exhibit different yield strengths; Hu et al 10 revealed that if primary particles have a high degree of short chain branching, the mechanical properties of their products at room temperature are significantly promoted; Martinez-Morlanes et al 11 found that a huge difference in the impact strength of the two grades of UHMWPE because of their different lengths of the molecular chains. Many researchers have devoted themselves to studying the structure-property relations of UHMWPE, [12][13][14][15] but unfortunately, these studies only reveal the effect of the UHMWPE structure on the mechanical properties at room temperature, and the relationship between the structure and cryogenic properties of UHMWPE is still inadequate.…”

Section: Introductionmentioning

confidence: 99%

Eminent differences in cryogenic toughness of ultra‐high molecular weight polyethylene with different entanglement densities

Sui

Cui

et al. 2022

J of Applied Polymer Sci

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It is generally believed that the ultra‐high molecular weight polyethylene (UHMWPE) performances are closely related to its molecular weight. However, when we sintered two brands of UHMWPE powders with similar molecular weights, GUR 4012 and GUR 400 Fine, we found they demonstrate eminent differences in cryogenic properties. Particularly, the cryogenic impact strength of GUR 4012 is 236% higher than that of GUR 400 Fine. To explain such an amazing phenomenon, we characterized UHMWPE microstructures and investigated the structure–property relations through scanning electron microscopy, x‐ray scattering diffraction, differential scanning calorimeter, and dynamic mechanical analysis. We observed only a slight difference in crystallization behaviors between them, but the entanglement density of GUR 4012 is much higher than that of GUR 400 Fine. Accordingly, we put forward a potential mechanism to analyze the eminent differences in cryogenic impact strengths. This work may promote our comprehension of the relation between the structure and performances of UHMWPE, which is conducive to promoting UHMWPE performance and broadening its industrial applications.

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Crystal morphology and corresponding physical properties of nascent ultra-high molecular weight polyethylene powder with short-branched chains

Cited by 12 publications

References 36 publications

Chain Dynamics of Partially Disentangled UHMWPE around Melting Point Characterized by 1H Low-Field Solid-State NMR

Chain Dynamics of Partially Disentangled UHMWPE around Melting Point Characterized by 1H Low-Field Solid-State NMR

Unraveling the influential mechanism of short-chain branching on the crystallization of trimodal polyethylene by molecular dynamics simulation

Eminent differences in cryogenic toughness of ultra‐high molecular weight polyethylene with different entanglement densities

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