Viscosity reduction and disentanglement in ultrahigh molecular weight polyethylene melt: Effect of blending with polypropylene and poly(ethylene glycol)

Xie, Meiju; Li, Huilin

doi:10.1016/j.eurpolymj.2007.05.016

Cited by 70 publications

(54 citation statements)

References 24 publications

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“…Equation (2) is derived from the statistical theory of rubber elasticity for the lightly crosslinked rubber system in very small strains [36]. It is usually applicable to amorphous polymers [35]. The factor three comes from the fact that for an elastic hydrogel the ratio of E to G should be equal to 3.0 for a small strain [37].…”

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 99%

“…where E 0 is the pseudoequilibrium storage modulus in the rubbery plateau region, q is the density, R is the gas constant, T is the thermodynamic temperature, M c is the average molecular weight between crosslinks [36], that is, the average molecular weight between entanglement loci [35]. Equation (2) is derived from the statistical theory of rubber elasticity for the lightly crosslinked rubber system in very small strains [36].…”

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 99%

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Self-crosslinkable complexes based on poly(ethylene glycol) (PEG), poly(itaconic acid) (PIA) and N-methylol acrylamide (NMA) as pharmaceutical hydrophilic matrices

et al. 2015

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The formation and characterization of poly(itaconic acid)/N-methylol acrylamide/poly(ethylene glycol) (PIA/NMA/PEG) complexes through in situ polymerization of itaconic acid on poly(ethylene glycol) was investigated. FTIR indicated that PEG crystallization was hindered by complex formation. The decrease in the crystallinity of PEG was also observed by DSC and indicated that the mobility of some PEG segments was inhibited by the presence of the polyacid. According to the swelling experiments, complexes proved to be suitable for use as excipient in the preparation of drug delivery systems responsive to pH changing. DMA was used to estimate the crosslink densities and the results were found to be in good agreement with the swelling results. Further, the adhesion strength of the synthesized polymers was used as preliminary evaluation of their potential of mucoadhesion. The results indicated that the adhesion performance is related to the presence of NMA. Drugs which suffer degradation in stomach pH, such as proteins and enzymes are potential candidates to be included in the systems based on PIA/ NMA/PEG to pass through the stomach (pH near to 1.2-3.5). Upon reaching the initial portion of the small intestine (pH [5.5), the polymer will swell and release the active substance via diffusion and/or erosion of the matrix.

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Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 99%

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 99%

Self-crosslinkable complexes based on poly(ethylene glycol) (PEG), poly(itaconic acid) (PIA) and N-methylol acrylamide (NMA) as pharmaceutical hydrophilic matrices

et al. 2015

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“…This area is the so called rubbery plateau. [12] It has been shown that the relationship between ‫ܯ‬ and the shear storage modulus ‫′ܩ‬ follows [7,13]:…”

Section: Dynamic Mechanical Analysismentioning

confidence: 99%

“…Dynamic mechanical analysis (DMA) has previously been employed to measure the crosslink and entanglement densities in a variety of polymers, including UHMWPE [7]. However, M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT DMA has not been employed to measure cross-linking in orthopaedic HXL UHMWPE materials.…”

Section: Introductionmentioning

confidence: 99%

Dynamical mechanical analysis as an assay of cross-link density of orthopaedic ultra high molecular weight polyethylene

et al. 2015

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The established gravimetric gel swell technique for measuring cross-link density in orthopaedic ultra-high molecular weight polyethylene (UHMWPE) is unable to detect local distributions of cross-link density that may be expected after in vivo degradation. Dynamic mechanical analysis (DMA) offers better spatial resolution of cross-linking. The ability to measure cross-link density in thin specimens using DMA would enable depth dependent analysis of cross-link density, opening the door to future studies on the effects of oxidation, antioxidants, and other factors on cross-linking.Thus, the aim of this study was to compare the performance of gel swell and DMA in the measurement of cross-link density in a range of highly cross-linked UHMWPE materials and to determine the relationship between the results of the two techniques. The results suggest that DMA and gel swell each offer advantages, and that both may have applications in the study of explanted orthopaedic UHMWPE bearings.

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“…An effective route is to reduce the melt viscosity by mixing UHMWPE with normal molecular weight polymer (NMWP) such as high density polyethylene (HDPE) [11], low density polyethylene (LDPE) [12], polypropylene (PP) [13], polyethylene glycol (PEG) [14], and polylactic acid (PLA) [15]. According to Takeshi S, Liu GD and others, some NMWP like LDPE and PP can conveniently and effectively reduce the viscosity of UHMWPE as well as retain or even enhance its mechanical properties [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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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Viscosity reduction and disentanglement in ultrahigh molecular weight polyethylene melt: Effect of blending with polypropylene and poly(ethylene glycol)

Cited by 70 publications

References 24 publications

Self-crosslinkable complexes based on poly(ethylene glycol) (PEG), poly(itaconic acid) (PIA) and N-methylol acrylamide (NMA) as pharmaceutical hydrophilic matrices

Self-crosslinkable complexes based on poly(ethylene glycol) (PEG), poly(itaconic acid) (PIA) and N-methylol acrylamide (NMA) as pharmaceutical hydrophilic matrices

Dynamical mechanical analysis as an assay of cross-link density of orthopaedic ultra high molecular weight polyethylene

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

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