Radiation crosslinking of LDPE and HDPE with 5 and 10 MeV electron beams

Gheysari, Djafar; Behjat, Abbas

doi:10.1016/s0014-3057(01)00084-2

Cited by 65 publications

(49 citation statements)

References 8 publications

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“…• C, held isothermally for 1 min, and then ramped (10 • C/min) to 400 • C to obtain the heat flow curves. Results were analyzed using TA universal thermal analyzer software.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

Chemical modification of polypropylene with diisocyanates for improved gas barrier and mechanical properties

2009

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ABSTRACT:In this investigation, modification of polypropylene (PP) with an objective to obtain packaging film with improved gas barrier properties has been studied. The chemical reaction of PP resin with hexamethylene diisocyanate and toluene diisocyanate was monitored by Fourier transform infrared spectroscopy, wherein the appearance of new peaks at 3333 cm −1 for N H stretching, 1620-1641 cm −1 for (C O) NH stretching and 1552-1578 cm −1 corresponding to N H bending in an amide moiety was observed for both the modified PP films. Films of excellent clarity and uniform thickness were obtained by the extrusion of cross-linked polypropylene. The barrier, mechanical, optical, and thermal properties of the modified PP films were studied. The results clearly indicated significant changes in gas barrier and mechanical properties. Food

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“…• C, held isothermally for 1 min, and then ramped (10 • C/min) to 400 • C to obtain the heat flow curves. Results were analyzed using TA universal thermal analyzer software.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

Chemical modification of polypropylene with diisocyanates for improved gas barrier and mechanical properties

2009

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“…Crosslinked POs have unique properties that non-crosslinked POs do not. Presently, there are three commercial methods used for the crosslinking of POs: (i) peroxide crosslinking [4], (ii) radiation crosslinking [5], and (iii) silane water-crosslinking [6]. Each method has its own applications according to its particular advantages.…”

Section: Introductionmentioning

confidence: 99%

The utility of sulfonic acid catalysts for silane water-crosslinked network formation in the ethylene–propylene copolymer system

Adachi

Hirano²

2008

J Sol-Gel Sci Technol

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Catalytic effects of Brönsted acid on the early kinetics of water-crosslinking reaction in the vinyltrimethoxysilane-grafted ethylene-propylene copolymer (EPR-g-VTMS) system were investigated by means of an attenuated total reflectance-Fourier transform infrared (ATR-FTIR) technique and gel fraction measurements. Four sulfonic acids with different substituent, including methanesulfonic acid (C1SO 3 H), 1-propanesulfonic acid (C3SO 3 H), 1-pentanesulfonic acid (C5SO 3 H), and dodecylbenzenesulfonic acid (C12PhSO 3 H), were selected to examine the progress and effect of progressive changes in the silane watercrosslinked network structure in comparison with a primary amine (n-octadecylamine, Lewis base). From the kinetic analysis using Arrhenius equation, we found that the frequency factors for both hydrolysis (ATR-FTIR) and condensation step (gel content) of EPR-g-VTMS decreased in the order of C1SO 3 H > C3SO 3 H > C5SO 3 H > C12PhSO 3 H, while the activation energy values for each reaction did not differ significantly.These relationships can be explained mainly on the basis of the diffusion factors of the sulfonic acids in EPRg-VTMS system. Moreover, the stress-strain curve comparison between water-crosslinked EPR-g-VTMS samples containing sulfonic acid and amine compound clearly indicated the difference in their tensile properties as a result of the catalyst variation; the use of sulfonic acid as water-crosslinking catalyst eventually achieves to the soft and tough water-crosslinked EPR-g-VTMS, while the hard and strong one was produced using amine catalyst. Not only the catalytic activity but also the type of the catalyst has eventually significant effects upon the physical properties of the water-crosslinked EPR-g-VTMS.3/32

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“…The conveyor speed was adjusted to a dose of 5 kGy during a single pass to prevent overheating of the specimen. 2,[11][12][13] The irradiated specimens were heated in an N 2 environment to prevent oxidative degradation at 110 and 145°C for 7 and 2 h, respectively, at a heating rate of 2°C/min. The specimens were cooled to room temperature at a cooling rate of 1°C/min.…”

Section: Heat Treatment After Eb Irradiationmentioning

confidence: 99%

“…After extraction, the specimens were dried at 80°C in a vacuum oven to constant weight. 4,13 The gel fraction was determined from the ratio of the weight of the dried extracted specimen (W d ) to the initial weight of the specimens (W i ). …”

Section: Gel Fraction Measurementmentioning

confidence: 99%

“…For instance, with UHMWPE (density ϭ ϳ0.93 g/cm 3 ), the penetration of a 1-MeV EB is about 3.58 mm and the maximum dose occurs at about 1.7 mm from the surface, theoretically. 1,13 One of the radiolytic events that occurs during the irradiation of PE is the formation of the trans-vinylene unsaturations. trans-Vinylene can be quantified using FTIR spectroscopy by the observation of the absorbance band at 965 cm Ϫ1 .…”

Section: Oxidation Of Uhmwpementioning

confidence: 99%

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Effect of electron beam irradiation on physical properties of ultrahigh molecular weight polyethylene

Kim

Kang

Nho

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:If a large amount of polymer radicals remain trapped after the irradiation of ultrahigh molecular weight polyethylene (UHMWPE), the radicals may result in a significant alteration of its physical properties during longterm shelf storage and implantation. An electron spin resonance spectroscopic study was undertaken to investigate the remaining free radicals in UHMWPE after electron beam irradiation up to 500 kGy in air and an N 2 environment. Heat treatment was employed at 110 and 145°C for various periods of time to decay the free radicals. The free radicals were rapidly decayed for 1 h and gradually decayed as a function of time with the heat treatment. The decay of the free radicals was completed more rapidly with a heat treatment at 145°C than at 110°C. Therefore, a longer heat treatment time is required to scavenge all the free radicals formed in UHMWPE at 110°C. The oxidation profiles showed that the oxidation index of the heat-treated UHM-WPE was lower than the oxidation index of the non-heattreated UHMWPE. The heat treatment of irradiated UHM-WPE can substantially reduce the concentration of free radicals; therefore, UHMWPE has resistance against long-term oxidative degradation.

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Radiation crosslinking of LDPE and HDPE with 5 and 10 MeV electron beams

Cited by 65 publications

References 8 publications

Chemical modification of polypropylene with diisocyanates for improved gas barrier and mechanical properties

Chemical modification of polypropylene with diisocyanates for improved gas barrier and mechanical properties

The utility of sulfonic acid catalysts for silane water-crosslinked network formation in the ethylene–propylene copolymer system

Effect of electron beam irradiation on physical properties of ultrahigh molecular weight polyethylene

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