Study on the foaming of crosslinked polyethylene

Abe, Shigehiko; Yamaguchi, Masayuki

doi:10.1002/1097-4628(20010321)79:12<2146::aid-app1022>3.0.co;2-q

Cited by 52 publications

(36 citation statements)

References 27 publications

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“…Solubility results agree well with previously shown rheology and creep results. These presented results correspond well with other researchers [8,9,18,35]. For example, Liu et al investigated UV photodegradation of polyethylene compared to ethylene-octene copolymers with an increasing octene content of 20, 30, and 38 wt %.…”

Section: Estimation Of G Values Of Crosslinking By the Charlesby-pinnsupporting

confidence: 91%

“…Abe et al [8] made foam from two ethylene-1-hexene copolymers; LL1 had 25 branches and LL2 had 7 branches per 1000 backbone carbon atoms with the same molecular weight, M n = 4.6ˆ10 4 g/mol. The foams were produced directly by moulding using 0.1-0.9 wt % of dicumylperoxide (DCP) and 8 phr of a blowing agent.…”

Section: Estimation Of G Values Of Crosslinking By the Charlesby-pinnmentioning

confidence: 99%

“…These applications include elastic fibres for apparel with improved UV resistance (to replace Elastane) [6], packaging, blood bags, and catheters in hospitals [7]. Crosslinked polyolefin foams have various kinds of applications, such as thermal insulation, floatation, automotive trim, and sporting goods [8,9]. For some applications it is necessary to crosslink these new elastic polyolefins because some of them have a very low melting point (in the range of 45-55˝C) [10].…”

Section: Introductionmentioning

confidence: 99%

“…One possibility is careful mixing with peroxide (the temperature must be kept low to avoid premature crosslinking during mixing) followed by high-temperature crosslinking of the moulded article [8,11]. Another method includes grafting by vinyltrimethoxy silane followed by exposure to water or humidity at elevated temperatures [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

“…It must be mentioned that the level of crosslinking was kept rather low compared to crosslinking levels in tyres, for example. This lower level of crosslinking is industrially important, for example, during foaming when the level of crosslinking must not be too high (bubbles cannot grow) or too low (bubbles collapse during foaming) [8,9]. Testing methods included dynamic mechanical analysis (DMA), rheology, a high-temperature creep test, and an analysis of the gel content.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Branching Density in Ethylene-Octene Copolymers on Electron Beam Crosslinkability

Svoboda

2015

Polymers

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Two ethylene-octene copolymers (EOC) with the same melt flow index (MFI = 3 g/10 min) but different octene contents, being 20 and 35 wt % (EOC-20 and EOC-35), were compared with regard to sensitivity to electron beam crosslinking. Dynamic mechanical analysis (DMA) revealed a large influence of the octene content on the storage modulus and the glass transition temperature (T g ) but a smaller influence of irradiation on the properties below melting point (T m ). Rheology at 150˝C pointed out large differences in samples crosslinked in the 0-60 kGy range and at lower frequencies (0.1-1 Hz). The loss factor tanδ confirmed that before irradiation the two copolymers were very similar, while after irradiation to 120 kGy, the EOC-35 had considerably lower tanδ than EOC-20, which corresponds to a better elasticity (or a higher level of crosslinking). A high-temperature creep test showed a considerably lower creep for EOC with a higher octene content. An analysis of the insoluble gel content exhibited higher values for EOC-35 confirming a higher level of crosslinking. Analysis according to the Charlesby-Pinner equation revealed increased crosslinking-to-scission ratio, G(X)/G(S), for EOC-35. While the G(X) value changed only slightly, a significant decrease in the G(S) value was discovered.

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Section: Estimation Of G Values Of Crosslinking By the Charlesby-pinnsupporting

confidence: 91%

Section: Estimation Of G Values Of Crosslinking By the Charlesby-pinnmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of Branching Density in Ethylene-Octene Copolymers on Electron Beam Crosslinkability

Svoboda

2015

Polymers

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Prediction of foamability of polyethylene terephthalate using viscous and elastic parameters

et al. 2017

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Rheological behavior and foamability of polyethylene terephthalate (PET) with different molecular structures were investigated. The aim of this study was to find out the viscous and elastic parameters which can predict the foaming properties of PET.It is found that the foams of strain hardening PET have high expansion ratios and fine cell morphologies. This is correlated with the contribution of strain hardening to the improvement of melt strength and failure strain during elongational experiments.Basing on the fact that foamability of a material is governed by its strain hardening (a pure elastic behavior), a viscous parameter (complex viscosity), and an elastic parameter (loss tangent) obtained from dynamic shear rheology are well linked to the expansion ratios of foams. These two parameters formed an optimized viscoelastic window, which is suitable for foaming. This means the foamability of PET can be determined by viscous and elastic parameters without consideration of molecular constitution. K E Y W O R D Sfoams, polyesters, rheology, viscoelastic properties

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Enhanced strain hardening in elongational viscosity for HDPE/crosslinked HDPE blend. I. Characteristics of crosslinked HDPE

Yamaguchi

Suzuki

Maeda

2002

J of Applied Polymer Sci

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Blending a crosslinked high-density polyethylene (xHDPE) enhances melt strength and strain hardening behavior in elongational viscosity of high-density polyethylene (HDPE) to a great degree. Gel fraction of xHDPE has a stronger effect on the strain hardening than sol fraction, although sol fraction also enhances the strain hardening to some degree. Further, the xHDPE crosslinked by peroxide in a compression mold exhibits more pronounced effect than xHDPE by radiation, which is attributed to the difference in the amount of the gel fraction. The xHDPE, which enhances the strain hardening, has sparse crosslink points in the network. Moreover, it was found from linear viscoelastic measurements, such as oscillatory modulus and relaxation modulus, that the xH-DPE is characterized as a critical gel, which was also supported by the result of tensile testing.

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Study on the foaming of crosslinked polyethylene

Cited by 52 publications

References 27 publications

Influence of Branching Density in Ethylene-Octene Copolymers on Electron Beam Crosslinkability

Influence of Branching Density in Ethylene-Octene Copolymers on Electron Beam Crosslinkability

Prediction of foamability of polyethylene terephthalate using viscous and elastic parameters

Enhanced strain hardening in elongational viscosity for HDPE/crosslinked HDPE blend. I. Characteristics of crosslinked HDPE

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