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Munier, Catherine; Gaillard-Devaux, E.; Tcharkhtchi, Abbas; Verdú, J.

doi:10.1023/a:1020091920606

Cited by 22 publications

(14 citation statements)

References 9 publications

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“…Figure 7 shows the relation between the crosslink degree and the proportion of non cross-linked region of stabilizer combination No. 1 …”

Section: Structure Of Cross-linked Regionmentioning

confidence: 99%

“…Many researchers had investigated the mechanical properties [1][2][3][4][5], durability [6][7][8][9], or lifetime prediction [10,11] of the plastic pipes such as polyethylene pipes, cross-linked polyethylene pipes, complex pipes, etc. It has been well known for a long time that polyethylene pipes under pressure exhibit a ductile failure at short-term and a brittle failure at long-term.…”

Section: Introductionmentioning

confidence: 99%

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Study on the Structure of Peroxide Cross-Linked Polyethylene Pipes with Several Stabilizers

Hirabayashi¹,

Iguchi²,

Yamada³

et al. 2013

MSA

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Cross-linked polyethylene (PEX) pipes used in hot water supply are required for high mechanical strength and high creep resistance at high temperature. Especially PEX-a pipes which are made by peroxide cross-linking have better performance, such as creep resistance and thermal shock resistance than the pipes made by the other cross-linking method. Because the PEX-a pipes indicate the higher cross-link degree as compared with the other PEX pipes. In this study, the PEX-a pipes which were mixed with several stabilizers were tested to evaluate the effects on cross-link degree and the oxygen induction time. And also they are evaluated with the chlorine aqueous solution by the performance of the long-term hydrostatic pressure test and the long-term hydro dynamic pressure test. As a result, it was found that the combination of antioxidants for PEX-a pipes plays an important role to prolong the oxygen induction time without inhibiting the cross-linking. From the results of the 1 H pulsed NMR measurement over the melting point of polyethylene, it was found that each peroxide PEX pipe with different antioxidant combinations indicated the different proportion and crosslink density of cross-linked region, in addition, that these pipes had the effective structure of cross-linking for the hydrostatic and hydrodynamic pressure test with the chlorine aqueous solution. Therefore, it was considered to be useful results for studies of the stricture of cross-linking of polyethylene.

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“…Figure 7 shows the relation between the crosslink degree and the proportion of non cross-linked region of stabilizer combination No. 1 …”

Section: Structure Of Cross-linked Regionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on the Structure of Peroxide Cross-Linked Polyethylene Pipes with Several Stabilizers

Hirabayashi¹,

Iguchi²,

Yamada³

et al. 2013

MSA

View full text Add to dashboard Cite

show abstract

“…In addition, cross‐linked PE may be suitable for applications that take place at higher temperatures . Hot water piping installation and wire coating are some of the major applications of cross‐linked PE …”

Section: Introductionmentioning

confidence: 99%

Molecular modification of slightly cross-linked HDPE: comparison of electron beam irradiation and peroxide treatments

Bahramzadeh

Try

2016

Polym. Adv. Technol.

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The aim of this study is to investigate the changes in molecular structure of high density polyethylene after slightly cross-linking with either electron beam irradiation or chemically with the peroxide method, by examining both the gel and sol parts of the polymer. Melt flow index and dynamic mechanical thermal analysis tests verify the crosslinking process after each treatment method. Differential scanning calorimetry and Fourier transformed infrared tests, together with rheology and viscometry tests, show that the cross-linking process has resulted in not only cross-linking long chains but also chain scission of short chains, thus broadening the molecular weight distribution. Because these created short chains act like lubricants, cross-linked chains flow easier. Therefore, the polymer remains processable according to the melt flow index test, and this will make the usage of slightly cross-linked high density polyethylene in injection molding processes possible.

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“…In this case, various mechanical/physical approaches have been proposed for lifetime prediction. [4][5][6] However, disinfectants, especially chlorine derivatives, are known to destroy organic compounds by free radical processes. It is true that PE presents a relatively high chemical stability, but zero radical reactivity would be surprising because radical reactions are never totally selective.…”

Section: Introductionmentioning

confidence: 99%

Towards a Non Empirical Kinetic Model for the Lifetime Prediction of Polyethylene Pipes Transporting Drinking Water

Colin

Audouin

Verdú

2009

Macromolecular Symposia

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Summary: A kinetic model has been elaborated to predict the lifetime of polyethylene pipes transporting slightly pressurized (3-12 bars) drinking water disinfected by free radical reagents. This model is composed of three levels: i) A system of differential equations, derived from a mechanistic scheme for radical chain oxidation in the presence of free radical reagents, giving access to the spatial distribution (in the pipe wall) of oxidation products and stabilizer concentration; ii) Equations allowing to predict the profiles of average molar masses from the spatial distribution of chain scissions and crosslinking events; iii) An empirical creep equation and a failure criterion derived from regression curves obtained in pure water (without disinfectant). It is assumed that the chemical degradation modifies only the time to transition between ductile and brittle regimes of failure, and that this time is linked to the weight average molar mass according to the classical power law. By superimposing these three levels, it is possible to predict the time to failure under the coupled effects of pressure and chemical degradation. This model is successfully applied to the case of chlorine dioxide.

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Cited by 22 publications

References 9 publications

Study on the Structure of Peroxide Cross-Linked Polyethylene Pipes with Several Stabilizers

Study on the Structure of Peroxide Cross-Linked Polyethylene Pipes with Several Stabilizers

Molecular modification of slightly cross-linked HDPE: comparison of electron beam irradiation and peroxide treatments

Towards a Non Empirical Kinetic Model for the Lifetime Prediction of Polyethylene Pipes Transporting Drinking Water

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