Extrusion of ultrahigh molecular weight polyethylene under ultrasonic vibration field

Liu, Gongde; Li, Huilin

doi:10.1002/app.12163

Cited by 51 publications

(32 citation statements)

References 21 publications

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“…In recent years, ultrasonic irradiation has been applied during polymer processing to control the morphology of polymers and their blends. The applications of ultrasonic irradiation in polymer processing mainly focus on the welding of thermoplastics, rubber vulcanization, in situ compatibilization of immiscible polymer blends, and so forth [18][19][20][21] . But effect of ultrasonic irradiation on molecular structure development of polymer melt is hardly reported.…”

Section: Introductionmentioning

confidence: 99%

Molecular structure development of metallocene‐catalyzed linear low density polyethylene under ultrasonic irradiation

Guo

Li³

2005

J Polym Sci B Polym Phys

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In this work, the effect of ultrasonic irradiation on molecular structure development of metallocene‐catalyzed linear low density polyethylene (mLLDPE) was studied. GPC results show that ultrasonic irradiation have influence on molecular weight and molecular weight distribution of mLLDPE. Molecular weight of mLLDPE decreases slightly at the initial 30 s of ultrasonic irradiation and then increases obviously; its distribution becomes wider with the increase of ultrasonic irradiation time. The power and frequency of ultrasonic irradiation have the distinct influence on molecular weight and its distribution of mLLDPE. DSC results show that ultrasonic irradiation has distinct influence on multiple step crystallizing behaviors of mLLDPE because of the change of branched chain in mLLDPE molecules. Thermal stability of mLLDPE is improved greatly because of micro‐crosslinking structure in mLLDPE molecule, which is formed in the presence of ultrasonic irradiation. A possible mechanism for molecular structure development of mLLDPE in the presence of ultrasonic irradiation is also proposed in this paper. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2121–2129, 2005

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Section: Introductionmentioning

confidence: 99%

Molecular structure development of metallocene‐catalyzed linear low density polyethylene under ultrasonic irradiation

Guo

Li³

2005

J Polym Sci B Polym Phys

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“…Consequently, the addition of PP significantly improved the melt flowability of UHMWPE and the die pressure was very stable during extrusion. Besides, the addition of PP (10 wt %) to UHMWPE can improve both the strength at break and the izod notched impact strength to some extent [25]. Therefore, two-phase morphologies and thick interface are respectively beneficial to the viscosity reductions and mechanical property maintenance of the UHMWPE/NMWP blends.…”

Section: Introductionmentioning

confidence: 98%

Metastable region of phase diagram: optimum parameter range for processing ultrahigh molecular weight polyethylene blends

Gai

Zuo

2011

J Mol Model

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Numerous studies suggest that two-phase morphology and thick interface are separately beneficial to the viscosity reduction and mechanical property maintainence of the matrix when normal molecular weight polymer (NMWP) is used for modification of ultrahigh molecular weight polyethylene (UHMWPE). Nevertheless, it is very difficult to obtain a UHMWPE/NMWP blend which may demonstrate both two-phase morphology and thick interface. In this work, dissipative particle dynamics simulations and Flory-Huggins theory are applied in predicting the optimum NMWP and the corresponding conditions, wherein the melt flowability of UHMWPE can be improved while its mechanical properties can also be retained. As is indicated by dissipative particle dynamics simulations and phase diagram calculated from Flory-Huggins theory, too small Flory-Huggins interaction parameter (χ) and molecular chain length of NMWP (N(NMWP)) may lead to the formation of a homogeneous phase, whereas very large interfacial tension and thin interfaces might also appear when parameters N(NMWP) and χ are too large. When these parameters are located in the metastable region of the phase diagram, however, two-phase morphology occurs and interfaces of the blends are extremely thick. Therefore, metastable state is found to be advisable for both the viscosity reduction and mechanical property improvement of the UHMWPE/NMWP blends.

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“…Therefore, injection molding is a difficult manufacturing process for UHMWPE. During the past decades, many processing methods have been developed for UHMWPE, such as compression molding [2,4,5,6] , extrusion molding [7][8][9] , drawing [10][11][12] and stretching [14] . In general, these processing methods can only be shaped into simple geometries in a production cycle.…”

Section: Introductionmentioning

confidence: 99%

Dry Sliding Wear Properties of Ultra-high Molecular Weight Polyethylene Parts Made by the Injection Molding Process

Kuo

Jeng

2011

Polymer-Plastics Technology and Engineering

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The objective of this study was to investigate the effects of various sliding wear test conditions on the tribological properties of UHMWPE. The results indicated that the wear resistance of UHMWPE in the sliding direction perpendicular to the melt flow direction was stronger than that in the sliding direction parallel with the melt flow direction. It was found that the X-Z plane obtains more serious incomplete molecular bondings and cracks than the Y-Z plane. The main wear mechanisms were plastic deformations and wrinkled formations. The UHMWPE hardness increases or decreases as the applied load and sliding frequency increases or decreases.

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Extrusion of ultrahigh molecular weight polyethylene under ultrasonic vibration field

Cited by 51 publications

References 21 publications

Molecular structure development of metallocene‐catalyzed linear low density polyethylene under ultrasonic irradiation

Molecular structure development of metallocene‐catalyzed linear low density polyethylene under ultrasonic irradiation

Metastable region of phase diagram: optimum parameter range for processing ultrahigh molecular weight polyethylene blends

Dry Sliding Wear Properties of Ultra-high Molecular Weight Polyethylene Parts Made by the Injection Molding Process

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