Influence of the irradiation conditions on the effect of radiation on polyethylene

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BOJANA SECEROV

2004-12-01

Full Text Available Two types of polyethylene, low density (LDPE and high density (HDPE, as well as low density polyethylene containing an antioxidant were subjected to g-irradiation in the presence of air and in water. The irradiated polymers were studied using IR spectrophotometric analysis. The radiation induced oxidative degradation was followed through the formation of oxygen containing groups by the development of bands in the 1850–1650 cm-1 region and double bonds formation by the development of bands in the 1050–850 cm-1 region. The crosslinking efficiency was determined by measuring the gel content by extraction with xylene. The radiation induced changes in the molecular structure, evolution of oxygen containing species and formation, of vinyl double bonds as well as of the crosslinking efficiency are discussed in terms of the properties of the polymers in an electric field of low strength.

Effects of gamma irradiation on polypropylene, polypropylene + high density polyethylene and polypropylene + high density polyethylene + wood flour

Energy Technology Data Exchange (ETDEWEB)

Reyes, J.; Albano, C.; Davidson, E.; Poleo, R. [Universidad Central de Venezuela, Caracas (Venezuela). Escuela de Quimica; Gonzalez, J.; Ichazo, M. [Universidad Simon Bolivar, Dept. de Mecanica, Caracas (Venezuela); Chipara, M. [Research Institute for Electrotechnics, Bucharest (Romania)

2001-04-01

The effect of the gamma-irradiation on the mechanical properties of the composites, Polypropylene (PP), PP+high density Polyethylene (HDPE), PP+ HDPE+wood flour, where HDPE is virgin and recycled, was studied. This paper discusses the behavior of the composites after exposure to various doses of gamma irradiation (1-7 MRads) in the presence of oxygen. The dependence of mechanical properties on the integral dose for a constant dose rate of 0.48 MRads/h confirms the influence of the irradiation. Strong effects on the elongation at break and break strength is noticed. The mathematical analysis suggests for the PP+r-HDPE a bimolecular process of the elongation at break. On the order hand, for the PP+HDPE a complex process is represented for a three exponential equation. (orig.)

Effects of gamma irradiation on polypropylene, polypropylene + high density polyethylene and polypropylene + high density polyethylene + wood flour

International Nuclear Information System (INIS)

Reyes, J.; Albano, C.; Davidson, E.; Poleo, R.; Chipara, M.

2001-01-01

The effect of the gamma-irradiation on the mechanical properties of the composites, Polypropylene (PP), PP+high density Polyethylene (HDPE), PP+ HDPE+wood flour, where HDPE is virgin and recycled, was studied. This paper discusses the behavior of the composites after exposure to various doses of gamma irradiation (1-7 MRads) in the presence of oxygen. The dependence of mechanical properties on the integral dose for a constant dose rate of 0.48 MRads/h confirms the influence of the irradiation. Strong effects on the elongation at break and break strength is noticed. The mathematical analysis suggests for the PP+r-HDPE a bimolecular process of the elongation at break. On the order hand, for the PP+HDPE a complex process is represented for a three exponential equation. (orig.)

Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

Energy Technology Data Exchange (ETDEWEB)

Bee, Soo-Tueen, E-mail: direct.beest@gmail.com [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin, E-mail: direct.tinsin@gmail.com [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2014-09-01

Highlights: •Electron beam irradiation on polyethylene (LDPE) and polylactic acid (PLA) blends. •Irradiated PLA/LDPE blends exhibit structural rearrangement to highly ordered structure. •Irradiated PLA/LDPE matrix extends continuity of polymer matrix with larger fibrils diameter. -- Abstract: The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20–80% LDPE and were exposed to electron beam irradiation dosages of 20–120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young’s modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure.

Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

International Nuclear Information System (INIS)

Bee, Soo-Tueen; Ratnam, C.T.; Sin, Lee Tin; Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang; Rahmat, A.R.

2014-01-01

Highlights: •Electron beam irradiation on polyethylene (LDPE) and polylactic acid (PLA) blends. •Irradiated PLA/LDPE blends exhibit structural rearrangement to highly ordered structure. •Irradiated PLA/LDPE matrix extends continuity of polymer matrix with larger fibrils diameter. -- Abstract: The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20–80% LDPE and were exposed to electron beam irradiation dosages of 20–120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young’s modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure

Effects of gamma-ray irradiation on tensile properties of ultradrawn polyethylene

International Nuclear Information System (INIS)

Iida, Shozo; Sakami, Hiroshi

1977-01-01

The deformation of ultradrawn polyethylene was previously shown that crystalline chains were pulled out by the tension applied to tie chains which connected crystal blocks. This paper deals with the effects of γ-ray irradiation on crosslinking which prevent crystalline chains being pulled out and to improve the tensile properties. The tensile strength of high density polyethylene, drawn by a factor of 40, increased from 73 to 113 kg/mm 2 at 20 0 C and from 13 to 42 kg/mm 2 at 80 0 C with increasing irradiation dose from zero to 100 Mrad. The tensile elongation, the residual strain measured by cyclic strain test, and the rate of stress decrease by the stress relaxation measurement diminished with increasing irradiation dose. These facts showed the existence of preventive effects by crosslinks on pulling. The stress-strain relation of crosslinked polymer was calculated thermodynamically from the melting of crystalline chains accompanied by the sliding of chains, assuming that the sliding of crystalline chains was brought about by an unbalance of the tension applied to tie chains with which both sides of crystalline chains were connected. The equation of stress was derived; stress increased with increasing strain and was proportional to the Gibbs' free energy of fusion. The observed stress-strain relations obeyed the above mentioned equation. (auth.)

Study of the characterization of crosslinking polyethylene foam by irradiation process with electron beam

International Nuclear Information System (INIS)

Dias, Djalma Batista

2007-01-01

The polyethylene foams are widely used. Their main applications are used for both home appliances to medical equipment. Beside that, they have applications in building and automotive industries. The foam properties depend on the density and its cellular structure, that is, the amount of open and closed cells, of the distribution and size of them. The methods of the crosslinking polyethylene foam production are classified in two types, according to the crosslinking method. One method is based on the chemical crosslinking, which utilizes peroxide as crosslinking agent. In the other method, the crosslinking is induced by electron beam radiation. The foams obtained from the crosslinking polyethylene by irradiation process presented a smooth and the homogeneous surface, and are formed basically by closed cells. The aim of this study was to apply the ionizing radiation from electron beam to crosslink low density polyethylene (LDPE), to obtain foams. Their morphological, thermal and mechanical properties were studied to evaluate the obtained samples. The samples of low density polyethylene (0,946 g/cm 3 ), containing 5% of azodicarbonamide (ADCA), as expander agent, were irradiated with electron beam with doses of 10, 20, 30, 40, 50, 60, 80 and 100 kGy. After the irradiation, these LDPE samples were put into an oven to obtain the foams. It was determined the crosslinking degree of the foams. Some samples were also thermally aged. The mechanical performance of the foams samples was evaluated by means of the tensile strength, compression, hardness, permanent deformation by compression and resilience. It was also carried out thermogravimetry and scanning electron microscopy (SEM). The results have shown that, in the interval of radiation doses studied, that the tensile strength increases with the increase of the crosslinking degree. The compression resistance results obtained from with samples with to radiation dose of 40 kGy showed significant decreasing. The resilience

Chlorination of irradiated polyethylene single crystals

International Nuclear Information System (INIS)

Grimm, H.J.

1978-01-01

The chlorination of electron beam-irradiation polyethylene (PE) single crystals was studied for a range of irradiation doses, temperatures, and chlorine interaction times. The results presented show that PE chlorination was quite extensive, even in unirradiated PE single crystals at 25 0 C in the dark. Electron Spin Resonance (ESR, EPR) was used in this study in order to determine the alkyl radical concentration, decay constant, and diffusivity for (unchlorinated) specimens. An alkyl radical diffusivity D/sub a/ = 1.6 x 10 -17 cm 2 /sec at 25 0 C was estimated from ESR data and alkyl radical migration as one-dimensional unsteady-state diffusion process. In irradiated PE, chlorination occurred mainly via chain reactions which were initiated by the irradiation-produced free radicals. Chlorine content values were determined by X-ray Energy Spectroscopy (XES). It was found that the magnitude of the chlorine uptake increased with increasing dose, and decreased with decreasing temperature at constant dose. Otherwise the observed PE chlorination phenomena was quite similar for all of the doses and temperatures studied here, consisting of a two step mechanism: a fast uptake which occurred between time tCl 2 = 0 - 5 minutes and a slower, approximately first-order rate of uptake which occurred between times tCl 2 = 5 - 120 minutes. Chlorination was essentially complete by time tCl 2 = 120 minutes. The rapid uptake probably occurred in the amorphous surface zones where Cl 2 is relatively high and the second, slower step was probably attributable to Cl 2 diffusion into the crystalline regions and subsequent chlorination there. Inasmuch as the PE density decreases with increasing dose (for 1-600 Mrad), Cl 2 diffusivity was enhanced, resulting in higher chlorine uptake values at higher doses

Long-term degradation of chemical structures and mechanical properties in polyethylene induced by ion-beam irradiation

International Nuclear Information System (INIS)

Oka, T.; Hama, Y.

2004-01-01

The long-term degradation in polyethylene irradiated with ion beams was studied. We found the changes of the chemical structures and the mechanical properties with time storage. S-PE has a good resistance to ion-beam irradiation because the crystallinity and density were very low. (author)

Modifications by {gamma} irradiation of polyethylene at very high molecular weight. Tribological behaviour for orthopedic applications; Modifications par irradiation {gamma} du polyethylene a tres haut poids moleculaire. Comportement tribologique pour des applications orthopediques

Energy Technology Data Exchange (ETDEWEB)

Chaix, N

2001-07-01

A new mode of sterilization by vacuum gamma irradiation is studied. This new mode improves significantly the polyethylene behaviour during the study in friction-corrosion against a stainless steel-316L sphere. (N.C.)

The effect of natural weathering on irradiated polyethylene films

International Nuclear Information System (INIS)

Khoylou, F.; Hassan Pour, S.

2002-01-01

Polyethylene is one of the extensive used plastics in outdoor uses. Outdoor durability of PE in modem agriculture is very important because of large scale food production. UV radiations contained in solar spectrum are the main cause of degradation in outdoor uses of plastics. So, light stabilization of PE has made considerable progress since the early years of its outdoor use. Radiation crosslinking of PE films for improving UV stability is one of the new research fields. In this work,the effect of UV stabilizers on the chemical and mechanical stability of PE have been compared with UV stabilizers and radiation crosslinking together. For this reason two low density polyethylene films were prepared.One film contained 3% of photostabilizers and antioxidant,and the other film was free of additives. The films were irradiated by EB at doses of 30-300 kGy, these crosslinked PE films were exposed to the outdoor condition for 2 years. Determination of the gel content shows that significant crosslinking yields are obtained at high doses. Effect of crosslinking and outdoor exposure on the degradation of stabilized and unstabilized PE films have been studied by FTIR. Data of FTIR show that outdoor degradation of unstabilized PE promote rapidly after irradiation and cause to distortion of samples after 4 months. While, stabilized PE samples show low changes during 2 years outdoor exposure. Mechanical properties of stabilized and unstabilized crosslinked PE films are also presented in this paper. (Author)

Effect of [gamma]-irradiation on latent tracks of polyethylene terephthalate (PET) film

Science.gov (United States)

Hiroki, A.; Asano, M.; Yamaki, T.; Yoshida, M.

2005-04-01

The pre-treatment effect of γ-irradiation on latent tracks of polyethylene terephthalate (PET) films bombarded with swift heavy ions was investigated by electric conductometry and scanning electron microscope (SEM) observation. The Xe-ion bombarded PET films were etched for 6 h in 0.2 M NaOH aqueous solution at 70 °C to prepare track-etched membranes. As γ-irradiation doses increased in the range of 0-160 kGy, the surface pore diameter obtained by SEM observation decreased while that obtained by conductometry became large. This inconsistent result between the two methods was due to an increase in the crosslinked region in the latent tracks caused by γ-irradiation.

Viscoelastic behaviour of stabilized polyethylenes irradiated with gamma rays

Energy Technology Data Exchange (ETDEWEB)

Novakovic, Lj; Gal, O; Stannett, V T

1987-01-01

Two-cycle creep recovery penetration measurements at 150/sup 0/C are used to determine the viscoelastic parameters for irradiated low density and linear low density polyethylenes, pure and with 0.5% antioxidant. The amplitudes and the time factors of each cycle are calculated using the mechanical model expression. From the differences between the creep parameters of the first and the second cycle, the contribution of the nonelastic component is considered. The efficiency of radiation crosslinking of different systems is discussed on the base of the corresponding compliances.

Radiation Chemistry of Polyethylenes for Total Joint Applications

International Nuclear Information System (INIS)

Muratoglu, O.K.

2006-01-01

Wear and fatigue damage of polyethylene could limit the longevity of total hip and knee reconstructions used to treat end-stage joint diseases. Wear debris causes peri-prosthetic osteolysis, resulting in bone loss and component loosening ultimately necessitating revision surgery. Wear rate of polyethylene can be reduced by radiation crosslinking. Irradiation not only crosslinks the amorphous phase of polyethylene but also creates residual free radicals (RFR), the precursor to long-term oxidation. We used post-irradiation melting to eliminate the RFRs and improve oxidative stability. We determined the molecular weight between crosslinks (M c ) as a function of radiation-dose level and showed the wear rate to scale linearly with M c . Irradiated and melted polyethylene, in clinical use since 1998, show a significant reduction in wear in vivo through radiographic follow-up studies and analysis of surgically explanted acetabular liners. Irradiation and melting reduces the crystallinity and mechanical properties of polyethylene therefore it cannot be used for high demand joint applications, such as posterior stabilized knees. We replaced the post-irradiation melting step with ?-tocopherol (vitamin-E) doping to stabilize the RFRs and prevent long-term stability and at the same time prevent the loss of mechanical properties. 100kGy irradiated polyethylene was soaked in 120 degree vitamin-E followed by a homogenization step at 120degree. The ?-tocopherol doped samples showed no detectable oxidation after accelerating aging at 80degree in air for 5 weeks. The wear rate was comparable to that of 100-kGy irradiated and melted polyethylene with both clean and third body added bovine serum lubrication. The fatigue strength of ?-tocopherol doped polyethylene (ΔKi=0.9MPa.m 1 /2) were higher than that of 100-kGy irradiated and melted polyethylene (ΔKi=0.5 MPa.m 1 /2). Similarly, the ultimate tensile and yield strength of α-tocopherol doped polyethylenes were significantly

Radioprotection by polyethylene glycol-protein complexes in mice

International Nuclear Information System (INIS)

Gray, B.H.; Stull, R.W.

1983-01-01

Polyethylene glycol of about 5000 D was activated with cyanuric chloride, and the activated compound was complexed to each of three proteins. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase were each radioprotectants when administered prophylactically to female B6CBF1 mice before irradiation. The dose reduction factor for these mice was 1.2 when 5000 units of polyethylene glycol-catalase was administered before 60 Co irradiation. Female B6CBF1 mice administered prophylactic intravenous injections of catalase, polyethylene glycol-albumin, or heat-denatured polyethylene glycol-catalase had survival rates similar to phosphate-buffered saline-injected control mice following 60 Co irradiation. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase have radioprotective activity in B6CBF1 mice, which appears to depend in part on enzymatic activities of the complex. However, no radioprotective effect was observed in male C57BL/6 mice injected with each polyethylene glycol-protein complex at either 3 or 24 hr before irradiation. The mechanism for radioprotection by these complexes may depend in part on other factors

Investigation on improvement of properties of polyethylene by γ-irradiation(1)

International Nuclear Information System (INIS)

Cho Sang Gyu; Chong Yong Mu; Li In Son.

1984-01-01

The change in properties and structure of low-density polyethylene(PEt) caused by γ-irradiation and the influence of the media such as air, vacuum, nitrogen and water on it at the absorption dose from 0 to 1MGy were investigated. By measuring solubility, molecular weight, gel-fraction and swelling degree of the radiated samples, crosslinking of PEt was determined, on the basis of it the relative efficiency of irradiation media was estimated. It was proved that the irradiation crosslinking of PEt in the air medium is not possible, and that water is a best medium for the irradiation crosslinking. By means of IR spectroscopy the change in amorphous content (absorption increase at 1300cm -1 and 1375cm -1 ), the increase of trans-vinylene content (at 946cm -1 ), and the decrease of vinyl (at 908cm -1 ) and vinylidene content were confirmed and the chemical reaction mechanism of the radiation modification was suggested. (author)

Characteristics of heat shrinkable high density polyethylene crosslinked by γ-irradiation

International Nuclear Information System (INIS)

Kang, Phil Hyun; Nho, Young Chang

2001-01-01

The effects of γ-irradiation on the crosslinking of high density polyethylene (HDPE) was investigated for the purpose of obtaining a suitable formulation for heat shrinkable materials. In this study the HDPE specimens were prepared by blending with cross linking agents and pressed into a 0.2 mm sheet at 180 .deg. C. γ-irradiation was conducted at 40 to 100 kGy in nitrogen. The heat shrinkable property and thermal mechanical property of the HDPE sheets have been investigated. It was found that the degree of crosslinking of the irradiated HDPE samples were increased with irradiation dose. Compared with the HDPE containing triallylisocyanurate, the HDPE containing trimethlol propane triacrylate shows a slight increase in crosslinking density. The heat transformation and dimension change of HDPE decreased with increasing radiation dose. The heat shrinkage of the samples increased with increasing annealing temperatures. The thermal resistance of HDPE increased upon the crosslinking of HDPE

Metal adsorption of gamma-irradiated carboxymethyl cellulose/polyethylene oxide blend films

Science.gov (United States)

El-Naggar, Amal A.; Magida, M. M.; Ibrahim, Sayeda M.

2016-03-01

Blend films of different ratios of carboxymethyl cellulose (CMC)/polyethylene oxide (PEO) were prepared by the solution casting method. To investigate the effect of irradiation on all properties of prepared blend, it was exposed to different gamma irradiation doses (10, 20, and 30 kGy). Physical properties such as gel fraction (GF) (%) and swelling (SW) (%) were investigated. It was found that the GF (%) increases with increasing irradiation dose up to 20 kGy, while SW (%) decreases with an increase in the irradiation doses for all blend compositions. Moreover, the structural and mechanical properties of the prepared films were studied. The results of the mechanical properties obtained showed that there is an improvement in these properties with an increase in both CMC and irradiation dose up to 20 kGy. The efficiency of metal ions uptake was measured using a UV spectrophotometer. The prepared films showed good tendency to absorb and release metal ions from aqueous media. Thus, the CMC/PEO film can be used in agricultural domain.

Natural rubber/high density polyethylene/ground rubber composites vulcanized by gamma irradiation

International Nuclear Information System (INIS)

Shaltout, N.A.; Abou zeid, M.M.; Khalil, A.M.; El Miligy, A.A.

2010-01-01

Natural rubber (NR) was blended mechanically with 50 phr high density polyethylene (HDPE). the mechanical, physical and thermal properties of NR/HDPE blend and its composites with different contents of ground tire rubber (GTR) before and after exposure to gamma irradiation to various doses up to 250 kGy were studied. Also, the change in structure morphology of irradiated NR/HDPE blend as well as NR/HDPE/GTR composites was examined by scanning electron microscope (SEM). The results showed that the substitution of a part of virgin NR with GTR decreases the mechanical and physical properties but not to the extent of deterioration . However, it was found that the mechanical and physical properties were improved after gamma irradiation . Composite of NR/GTR/HDPE (75/25/50) showed good properties. Scanning electron microscope showed homogeneity between the irradiated composites ingredients.

Characteristics of recycled and electron beam irradiated high density polyethylene samples

International Nuclear Information System (INIS)

Cardoso, Jessica R.; Gabriel, Leandro; Geraldo, Aurea B.C.; Moura, Eduardo

2015-01-01

Polymers modification by irradiation is a well-known process that allows degradation and cross-linking in concurrent events; this last is expected when an increase of mechanical properties is required. Actually, the interest of recycling and reuse of polymeric material is linked to the increase of plastics ending up in waste streams. Therefore, these both irradiation and recycling process may be conducted to allow a new use to this material that would be discarded by an improvement of its mechanical properties. In this work, the High Density Polyethylene (HDPE) matrix has been recycled five times from original substrate. The electron beam irradiation process was applied from 50 kGy to 200 kGy in both original and recycled samples; in this way, mechanical properties and thermal characteristics were evaluated. The results of applied process and material characterization are discussed. (author)

Characteristics of recycled and electron beam irradiated high density polyethylene samples

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Jessica R.; Gabriel, Leandro; Geraldo, Aurea B.C.; Moura, Eduardo, E-mail: jrcardoso@ipen.br, E-mail: lgabriell@gmail.com, E-mail: ageraldo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Polymers modification by irradiation is a well-known process that allows degradation and cross-linking in concurrent events; this last is expected when an increase of mechanical properties is required. Actually, the interest of recycling and reuse of polymeric material is linked to the increase of plastics ending up in waste streams. Therefore, these both irradiation and recycling process may be conducted to allow a new use to this material that would be discarded by an improvement of its mechanical properties. In this work, the High Density Polyethylene (HDPE) matrix has been recycled five times from original substrate. The electron beam irradiation process was applied from 50 kGy to 200 kGy in both original and recycled samples; in this way, mechanical properties and thermal characteristics were evaluated. The results of applied process and material characterization are discussed. (author)

Characterization of injected linear low density polyethylene (LLDPE) irradiated by gamma-ray

International Nuclear Information System (INIS)

Oliveira, Ana C.F.; Parra, Duclerc F.; Ferreto, Helio F.R.; Lugao, Ademar B.

2013-01-01

The aim of this paper is to investigate of gamma irradiation effects on linear low density polyethylene (LLDPE) injected. Polymers processed by gamma radiation have new physical-chemical and mechanical properties. The ionizing radiation promotes chain scission and creates free radicals which can recombine, providing their annihilation, for crosslinking or branching. The polymer was irradiated with a source of 60 Co at doses of 5, 10, 20, 50 or 100 kGy at about 5 kGy s -1 rate, at room temperature. The changes in molecular structure of LLDPE were evaluated using melt flow index, gel fraction, differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FT-IR) and thermogravimetry analysis (TG). The results showed that the properties depend on dose irradiation. (author)

Role of the irradiation temperature on the modifications of swift-heavy-ion irradiated polyethylene

International Nuclear Information System (INIS)

Melot, M.; Ngono-Ravache, Y.; Balanzat, E.

2003-01-01

The damage processes triggered by swift heavy ions, SHI, can be very different to those induced by classical low ionising particles. This is due to the very high electronic stopping power, (dE/dx) e , of SHI. This paper concerns the effects of SHI on polyethylene, PE. In PE, low (dE/dx) e irradiations induce crosslinking and in-chain double bond formation. At high (dE/dx) e , the creation yield of vinyl groups becomes significant. Above a (dE/dx) e threshold, alkyne and allene groups appear. We present results on low temperature irradiations that bring new enlightenment on the damage process by preventing the migration of radiation-induced radicals and molecules. Two SHI specific modifications are studied: vinyl groups and alkyne end groups. We have irradiated PE films with oxygen and sulphur beams at 13.6 and 11.2 MeV/amu, respectively. The modifications were followed by in situ infrared spectroscopy (FTIR). We have performed irradiations at 8 and 290 K. The samples irradiated at 8 K have been annealed up to 290 K for investigating the effect of radical migration. Lowering the irradiation temperature to 8 K increases the creation yield of vinyl groups and alkyne end groups. The enhancement factor between 290 and 8 K is around three. Consequently the formation of defects specific to SHI irradiations is sensitive to radical migration and hence requires some time. During annealing, the alkyne concentration remains stable indicating that the creation of this group cannot be induced by radical recombination. The annealing spectra of vinyl groups are more complex

Study of crosslinking onset and hydrogen annealing of ultra-high molecular weight polyethylene irradiated with high-energy protons

Science.gov (United States)

Wilson, John Ford

1997-09-01

Ultra high molecular weight polyethylene (UHMW-PE) is used extensively in hip and knee endoprostheses. Radiation damage from the sterilization of these endoprostheses prior to surgical insertion results in polymer crosslinking and decreased oxidative stability. The motivation for this study was to determine if UHMW-PE could be crosslinked by low dose proton irradiation with minimal radiation damage and its subsequent deleterious effects. I found that low dose proton irradiation and post irradiation hydrogen annealing did crosslink UHMW-PE and limit post irradiation oxidation. Crosslinking onset was investigated for UHMW-PE irradiated with 2.6 and 30 MeV H+ ions at low doses from 5.7 × 1011-2.3 × 1014 ions/cm2. Crosslinking was determined from gel permeation chromatography (GPC) of 1,2,4 trichlorobenzene sol fractions and increased with dose. Fourier transform infrared spectroscopy (FTIR) showed irradiation resulted in increased free radicals confirmed from increased carbonyl groups. Radiation damage, especially at the highest doses observed, also showed up in carbon double bonds and increased methyl end groups. Hydrogen annealing after ion irradiation resulted in 40- 50% decrease in FTIR absorption associated with carbonyl. The hydrogen annealing prevented further oxidation after aging for 1024 hours at 80oC. Hydrogen annealing was successful in healing radiation damage through reacting with the free radicals generated during proton irradiation. Polyethylenes, polyesters, and polyamides are used in diverse applications by the medical profession in the treatment of orthopedic impairments and cardiovascular disease and for neural implants. These artificial implants are sterilized with gamma irradiation prior to surgery and the resulting radiation damage can lead to accelerated deterioration of the implant properties. The findings in this study will greatly impact the continued use of these materials through the elimination of many problems associated with radiation

The influence of oxidation on space charge formation in gamma-irradiated low-density polyethylene

CERN Document Server

Chen, G; Xie, H K; Banford, H M; Davies, A E

2003-01-01

The research presented in this paper investigates the role of oxidation in the formation of space charge in gamma-irradiated low-density polyethylene after being electrically stressed under dc voltage. Polyethylene plaques both with and without antioxidant were irradiated up to 500 kGy using a sup 6 sup 0 Co gamma source and space charge distributions were measured using the piezoelectric induced pressure wave propagation method. It has been found that a large amount of positive charge evolved adjacent to the cathode in the sample without antioxidant and was clearly associated with oxidation of the surface. The amount of charge formed for a given applied stress increased with the dose absorbed by the material. A model has been proposed to explain the formation of space charge and its profile. The charge decay after the removal of the external applied stress is dominated by a process being controlled by the cathode interfacial stress (charge injection) rather than a conventional RC circuit model. On the other ...

Effects of high energy (MeV) ion beam irradiation on polyethylene terephthalate

International Nuclear Information System (INIS)

Singh, Nandlal; Sharma, Anita; Avasthi, D.K.

2003-01-01

Irradiation effects of 50 MeV Li 3+ ion beams in polyethylene terephthalate (PET) films were studied with respect to their structural and electrical properties by using Fourier transform infrared (FTIR) spectroscopy and ac electrical measurement in the frequency range: 50-100 kHz at different temperatures of 30-150 deg. C. It is found that ac resistivity of PET decreases as frequency increases. The temperature dependencies of dielectric loss tangent exhibit a peak (T g ) at 60 deg. C. The capacitance value of irradiated PET is almost temperature independent and ones increases with an increasing of lithium fluence. FTIR spectra show various bands related to C-H, C-O, C-O-C molecular bonds and groups which get modified or break down due to ion beam irradiation

Influence of UV-Irradiation on Latent Tracks in Polyethylene Terephthalate Films

International Nuclear Information System (INIS)

Wen Qi; Wang Peng-Fei; Ling Yun; Wang Mao; Yan Dong-Xiao; Wang Yu-Gang; Cao Xing-Zhong; Wang Bao-Yi

2016-01-01

Polyethylene terephthalate (PET) films in thickness of 12 μm are irradiated by Xe and Au ions at the energies of 9.5 and 11.4MeV/u and with the ion fluence from 5 × 10"9 cm"−"2 to 1 × 10"1"1 cm"−"2. After irradiation, ultra-violet lights are used to illuminate the samples with latent tracks at the wavelength of 365 nm with flux density of 4.2 mW/cm"−"2. UV-irradiation effects on tracked PET are investigated by the UV-vis spectrum and positron annihilation lifetime spectroscopy (PALS). It is found that carbonaceous clusters in PET films are generated by ion irradiation and decomposed with UV illumination by calculating the optical energy band gap E_g in the UV-vis spectrum. The free volumes behave differently in track and bulk after UV illumination. In our experiment, the PALS results show an increase in radius and density of free volume in tracked PET films after UV treatment, which indicates an expansion in radius of latent tracks. (paper)

Pre-irradiation grafting of hydrophilic monomers onto polyethylene: Pt. 1

International Nuclear Information System (INIS)

Gargan, K.; Kronfli, E.; Lovell, K.V.

1990-01-01

An investigation was carried out to identify compounds which are suitable for use as homopolymerisation inhibitors when grafting acrylic acid or methacrylic acid onto pre-irradiated low-density polyethylene. It was found that certain transition metal compounds were able to suppress the formation of homopolymer whilst still allowing significant levels of grafting to take place. For acrylic acid the most suitable inhibitor found was ferrous sulphate, whilst cupric sulphate or potassium ferrocyanide were favoured for use with methacrylic acid. The influence of the inhibitor concentration on the degree of grafting was also investigated. (author)

Modifications by γ irradiation of polyethylene at very high molecular weight. Tribological behaviour for orthopedic applications

International Nuclear Information System (INIS)

Chaix, N.

2001-07-01

A new mode of sterilization by vacuum gamma irradiation is studied. This new mode improves significantly the polyethylene behaviour during the study in friction-corrosion against a stainless steel-316L sphere. (N.C.)

Pre-irradiation induced emulsion graft polymerization of acrylonitrile onto polyethylene nonwoven fabric

International Nuclear Information System (INIS)

Liu Hanzhou; Yu Ming; Deng Bo; Li Linfan; Jiang Haiqing; Li Jingye

2012-01-01

Acrylonitrile has been widely used in the modification of polymers by graft polymerization. In the present work, pre-irradiation induced emulsion graft polymerization method is used to introduce acrylonitrile onto PE nonwoven fabric instead of the traditional reaction in organic solvents system. The degree of grafting (DG) is measured by gravimetric method and the kinetics of the graft polymerization is studied. The existence of the graft chains is proven by Fourier transform infrared spectroscopy (FT-IR) analysis. Thermal stability of the grafted polymer is measured by Thermogravimetric analysis (TGA). - Highlights: → Acrylonitrile is grafted onto pre-irradiated polyethylene (PE) nonwoven fabrics. → Emulsion system is applied, for the graft polymerization avoids organic solvent. → Kinetic of the pre-irradiation induced graft polymerization is studied. → Optimal condition is determined at the temperature below the b.p. of acrylonitrile.

Thermomechanical method for evaluation of the crosslinking parameters in irradiated polyethylene

Energy Technology Data Exchange (ETDEWEB)

Novakovic, Lj; Gal, O; Stannett, V T; Charlesby, A

1989-01-01

The measurement of penetration deformation above the melting point was used for determination of viscoelastic parameters, compliance and retardation time, in ..gamma..-irradiated polyethylene systems. The time-dependent penetration deformation was followed over two creep and recovery cycles. The five-element mechanical model equation was used for calculation of amplitudes, time factors and remained deformations. The modulus of elasticity, derived from the equilibrium compliance was used to obtain M/sub e/ the value of the average molecular weight between crosslinks.

Response of CR-39 Detector Against Fast Neutron Using D-Polyethylene and H-Polyethylene Radiator

International Nuclear Information System (INIS)

Sofyan, Hasnel

1996-01-01

The research on the response of detector CR-39 by using D-Polyethylene and H-Polyethylene radiator has been carried out. The optimum number of nuclear tracks was found with the use of 30 % NaOH at 80 + 0,5oC for 80 minutes of etching time. The comparison of CR-39 detector response caused by D-Polyethylene radiator against H-Polyethylene radiator of irradiation in air, were found to be 1.18 and 0.84 for 241Am-Be neutron source and neutron source from reactor respectively. For phantom irradiation, the results were found to be 1.75 for 241Am-Be neutron source, and 0.77 for neutron source from reactor

Process for molding improved polyethylene

International Nuclear Information System (INIS)

Kanai, Masanori; Aine, Norio; Nakada, Shinsaku.

1962-01-01

Various configurations in size and shape of polyethylene are molded by: (a) irradiating powders of polyethylene with ionizing radiations in the presence of oxygen to the extent of producing substantially no cross-linking among the molecules of polyethylene, and thereafter (b) molding the thus irradiated powders of polyethylene at 100-250 0 C to cross-link the molding. In this process, a uniform and desirable degree of cross-linking and any desirable configuration are provided for the polyethylene molding. Any extruder and any molding machine producing heat can be employed in this process. In embodiments, the radiation dose units may preferably be 1x10 6 to 1.5x10 7 roentgen. The ionizing radiations may be X-rays, gamma-rays or electron beams, but preferably gamma-rays. The preheating prior to molding may be effected in vacuum, in inert gas, or in oxygen at 100-250 0 C, but preferably in oxygen at 100 0 C. In an example, a polyethylene powder of 100 mesh was irradiated with gamma-rays from a Co-60 source with a dose of 3.1x10 6 r at a dose rate of 5.5x10 4 r/hr in air, then preheated in air at 80 0 C for 1 hr, and finally extruded to form a rod of 5 mm phi at 200 0 C. max. The degree of product cross-linking was 0% after irradiation in step (a), and 38% after heating in step (b). (Iwakiri, K.)

Gamma irradiation effect on thermo shrink polyethylene tube: Case study

International Nuclear Information System (INIS)

Naurah Mat Isa; Siti Zulaiha Hairaldin; Mohd Yusof Hamzah; Zulkafli Ghazali

2010-01-01

The production technology of heat shrinkable tubes is based on the industrial usage of so-called memory effect in some polymers. Many polymers can be rendered heat shrinkable, particularly polyolefins by introducing crosslinking in the polymer backbone. Heat shrinkable tubes and moulded parts provide mechanical and/or chemical and/or electrical protection. . In this work, irradiation from Co-60 was used to impart crosslinking in polymer and thus modify their mechanical and thermal properties. Heat shrinkable or thermo shrink polyethylene (PE) tube with diameter 6.4 mm was selected to evaluate crosslinking behaviour from the gamma irradiation exposure at 5 different doses (120, 140, 160, 200 and 220 kGy). The gel content (%), tensile properties and thermal behavior and stability of the tubes were measured using DSC and TGA. Tubes irradiated at 140 kGy and 160 kGy showed better tensile properties than those at 120, 200 and 220 kGy doses. Maximum percent of crystallization was observed at 160 kGy and temperature required to crystallize is lower than melting temperature due to changes in molecular orientation. Thermal decomposition of the irradiated tubes occurred at 430-450 degree Celsius which is lower than the unirradiated sample. Gel content analysis for samples irradiated at 180-220 kGy yield up to 30 to 40 % gel fraction. Although the gel fractions are higher than other dose, the samples are expected to experience chain scission presumably due to localized gel formation. (author)

Radiation effects on polyethylenes

International Nuclear Information System (INIS)

Suzuki, T.; Oki, Y.; Numajiri, M.; Miura, T.; Kondo, K.; Tanabe, Y.; Ishiyama, M.; Ito, Y.

1992-01-01

Radiation effects on four kinds of polyethylenes were studied from the viewpoints of mechanical properties, free radicals and free volumes. The samples were irradiated using a cobalt 60 gamma source to give doses up to 3MGy. The degradation of mechanical strength due to gamma-irradiation was evaluated by the elongation at break and its tensile strength. Radiation induced free radicals were measured by ESR. Free volumes observed by the o-Ps component of the positron annihilation spectrum are normally the large ones located in the amorphous regions and after irradiation these are created in crystalline regions, too. The sizes and the relative numbers of free volumes were evaluated by lifetimes and intensities of a long-lived component of positronium, respectively. Using these data, the properties of polyethylenes before and after irradiation are discussed. (author)

The thermomechanical method for evaluation of the crosslinking parameters in irradiated polyethylene

International Nuclear Information System (INIS)

Novakovic, Lj.; Gal, O.; Stannett, V.T.; Charlesby, A.

1989-01-01

The measurement of penetration deformation above the melting point was used for determination of viscoelastic parameters, compliance and retardation time, in γ-irradiated polyethylene systems. The time-dependent penetration deformation was followed over two creep and recovery cycles. The five-element mechanical model equation was used for calculation of amplitudes, time factors and remained deformations. The modulus of elasticity, derived from the equilibrium compliance was used to obtain M e the value of the average molecular weight between crosslinks. (author)

Permeability coefficient of proton irradiated polyethylene terephatalate thin films

International Nuclear Information System (INIS)

Bassani, L.C.; Santos, W.M.S.; Marechal, B.

1983-01-01

The principle of operation of an apparatus developed to study gas permation through thin films is described and the measurement method is discussed. Use is made of diffusion theory to obtain a expression for the permeability coefficient as a function of the rate of increase of the pressure in the receiving volume. The Gibbs function for permeation of Helium through Polyethylene Terephtalate (P.E.T.) is determined. The permeability coefficient of Helium is found to increase significantly with the range of the implanted protons although the incident charge has been kept constant. The hypothesis of structural modifications of the proton implanted P.E.T. seems to be confirmed by small angles X-rays scattering experiments on the irradiated samples. (Author) [pt

Swift heavy ion irradiation effects on carbonyl and trans-vinylene groups in high and low density polyethylene

International Nuclear Information System (INIS)

Grosso, M.F. del; Chappa, V.C.; Arbeitman, C.R.; Garcia Bermudez, G.; Behar, M.

2009-01-01

In this work, we have studied the effects of swift heavy ion irradiation on the creation of new functional groups in high and low density polyethylene (HDPE and LDPE). Polymers were irradiated with different ions (6.77 MeV He and 47 MeV Li) and fluences. The induced changes were analyzed by Fourier transform infrared (FTIR) spectroscopy. Creation and damage cross sections for some groups were compared for two different types of PE.

Swift heavy ion irradiation effects on carbonyl and trans-vinylene groups in high and low density polyethylene

Energy Technology Data Exchange (ETDEWEB)

Grosso, M.F. del, E-mail: delgrosso@tandar.cnea.gov.a [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA (Argentina); Chappa, V.C. [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA (Argentina); CONICET (Argentina); Arbeitman, C.R. [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA (Argentina); Garcia Bermudez, G. [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA (Argentina); CONICET (Argentina); Escuela de Ciencia y Tecnologia, UNSAM (Argentina); Behar, M. [Instituto de Fisica, UFRGS, Porto Alegre (Brazil)

2009-10-01

In this work, we have studied the effects of swift heavy ion irradiation on the creation of new functional groups in high and low density polyethylene (HDPE and LDPE). Polymers were irradiated with different ions (6.77 MeV He and 47 MeV Li) and fluences. The induced changes were analyzed by Fourier transform infrared (FTIR) spectroscopy. Creation and damage cross sections for some groups were compared for two different types of PE.

Radiation effects on polyethylene foam of open cell type

International Nuclear Information System (INIS)

Tang Beilin; Kanako Kaji; Iwao Yoshizawa; Choji Kohara; Motoyoshi Hatada

1991-01-01

The effects of electron beam irradiation on polyethylene foam of open cell type have been studied. Experiments for determining of gel fraction and physical-mechanical properties of irradiated polyethylene foam of open cell type as a function of dose, respectively, were carried out. The dimensional stability of irradiated specimens at elevated temperatures was measured. It was found that tensile strength did not change and gel fraction increased when the specimen was irradiated in nitrogen atmosphere with increasing dose up to 300 kGy. The result shows that dimensional stability of polyethylene foam of open cell type after being kept in an oven at 70 deg C and 110 deg C for 22 h is improved by irradiation in nitrogen atmosphere. The similar results of irradiated EVA foam of open cell type irradiated foam of open cell type were obtained

Accounting aspects of contracts for the operation of public water supply assets in WSS operators

Directory of Open Access Journals (Sweden)

Nedyalka Alexandrova

2017-12-01

Full Text Available The article investigates and analyses the nature of the Contracts for exploitation of WSS assets concluded between the Water Supply and Sewerage Associations and operators under the Water Act in order to outline the opportunities for accounting of the assets and liabilities resulting from these contracts. The contracts, as well as the WSS Associations, are new and unique for Bulgarian practice phenomena, affecting the entire water supply sector and their reporting poses considerable difficulties in practice. The article is based on an analysis of the normative requirements of the Water Act, a study of the clauses of the contracts, as well as their comparison with the concession contracts. Based on the analysis of their economic nature and under the requirements of the International Accounting Standards, a model of accounting for the assets and liabilities arising from these contracts is proposed, including their presentation and valuation in the financial statements of the operators.

Thermal expansivity of highly-stretched linear polyethylene with extended chains irradiated with different doses of γ-rays

International Nuclear Information System (INIS)

Turetskij, A.A.; Chvalun, S.N.; Zubov, Yu.A.; Bakeev, N.F.

1993-01-01

Temperature begavior of crystal lattice parameters of highly-stretched samples of linear polyethylene with extended chains irradiated with different doses of γ-rays was studied. It was found that transverse vibrations of macromolecular chains are excited at irradiation doses D≥500 Mrad and temperatures close to the melting temperature of the crystallites. These vibrations cause a sharp increase in the latiice parameter a. But no phase transition to the hexagonal packing occurs. It was shown that the thermal expansivity of the lattice parameter c changes its sign at high irradiation doses. These results are explained by the presence in the crystallites of samples irradiated with large doses of a considerable number of intermolecular chemical bonds

Thermogravimetric studies of the thermo-oxidative stability of irradiated and unirradiated polyethylene

International Nuclear Information System (INIS)

Novakovic, L.; Gal, O.; Markovic, V.; Stannett, V.T.

1985-01-01

In part one of this series the effects of a phenolic, an amine and a thioester antioxidant on the thermo-oxidative stability of irradiated and unirradiated low-density polyethylene was reported. In this paper the effects of combined phenolic and thioester stabilizers are described. Isothermal thermogravimetric analysis was used to study the systems. Pronounced synergism was observed with the induction periods, the time when the initial weight loss begins and the 5% weight loss. At about 50% of each stabilizer increases greater than twofold were observed both with the unirradiated and irradiated polymers. The rate constants for oxygen uptake were decreased. However, the rates of degradation at 5% weight loss fell between the values of the two pure stabilizers with no pronounced synergism in either case. In the absence of oxygen little effect of either antioxidant or their mixtures was observed. The corresponding activation energies were somewhat higher, however, with the irradiated samples containing antioxidants. Dynamic thermogravimetry was used for this study. A kinetic analysis indicated that there were somewhat different modes of degradation at lower- and higher-temperature ranges. (author)

Process for producing chlorinated polyethylene

International Nuclear Information System (INIS)

Nose, Shinji; Takayama, Shin-ichi; Kodama, Takashi.

1970-01-01

A process for chlorinated polyethylene by the chlorination of an aqueous suspension of polyethylene without the use catalysts is given, using 5-55% by gel content of cross-linked polyethylene powders. The products have favorable material workability, transparency, impact strength and tensile properties. In the case of peroxide cross-linking, a mixture of peroxides with polyethylene must be ground after heat treatment. The polyethylene may preferably have a gel content of 5-55%. The chlorination temperature may be 40 0 C or more, preferably 60 0 to 160 0 C. In one example, high pressure polymerized fine polyethylene powders of 15μ having a density of 0.935 g/cc, a softening point of 114 0 C, an average molecular weight of 35,000 were irradiated in air with 40 Mrad electron beams from a 2 MV Cockcroft-Walton type accelerator at room temperature. The thus irradiated polyethylene had a gel content of 55% and a softening point of 119 0 C. It was chlorinated upto a chlorine content of 33% at 100 0 C. Products were white crystals having a melting point of 122 0 C and a melting heat value of 32 mcal/mg. A sheet formed from this product showed a tensile strength of 280 kg/cm 2 , an elongation of 370% and a hardness of 90. (Iwakiri, K.)

Study of the effect of gamma irradiation on carbon black loaded low-density polyethylene films

International Nuclear Information System (INIS)

Salem, M.A.; Hussein, A.; El-Ahdal, M.A.

2003-01-01

The effect of gamma irradiation on the tensile and physico-chemical properties of low-density polyethylene (LDPE) films loaded with different concentrations of carbon black (C.B) has been studied. The results showed that the behavior of the samples during gamma irradiation is complicated and this may be due to scission and the interaction between oxidation and crosslinking processes. The tensile properties are modified by the presence of carbon black. Film sample containing 7% C.B was found to exhibit a nearly stabilized tensile behavior with radiation dose, which allows to use this formulation in packaging for food sterilization and in preservation of weak cobalt-gamma sources. (author)

Crosslinking of commercial polyethylenes by 10 MeV electrons

International Nuclear Information System (INIS)

Singh, A.; Lopata, V.J.; Kremers, W.; Sze, Yu-keung

1995-08-01

Commercial polyethylenes were irradiated with 10 MeV electrons to induce crosslinking. The gel fraction data measured as a function of total dose suggests that crosslinking proceeds on irradiation, as expected. A number of the properties of the irradiated polyethylenes, such as the degree of oxidation, crystallinity and thermal degradation, were studied by Fourier transform infrared/photo acoustic spectroscopy, X-ray diffraction, and a pyrolysis technique coupled with gas chromatography and mass spectrometry. The results of this study suggest that commercial polyethylenes can be crosslinked to a gel fraction of ∼70%, required for wire and cable applications, by 10 MeV electrons. (author). 35 refs., 6 figs

Thermal, tensile and rheological properties of low density polyethylene (LDPE) processed irradiated by gamma-ray

International Nuclear Information System (INIS)

Ferreto, Helio F.R.; Oliveira, Ana C.F. de; Parra, Duclerc F.; Lugao, Ademar B.

2013-01-01

The aim of this paper is to investigate structural changes of low density polyethylene (LDPE) modified by ionizing radiation (gamma rays). The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. The samples were prepare in hydraulic press in temperature 180 deg C after was irradiated with gamma source of 60 Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h in inert atmosphere. The changes in molecular structure of LDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere. (author)

Physico-chemical characterization of polyethylene of ultra high molecular weight modified with gamma irradiation and heavy ions

International Nuclear Information System (INIS)

Lagarde, M; Del Grosso, M; Fasce, D; Dommarco, R; Laino, S; Fasce, L.A

2012-01-01

The ultra high molecular weight polyethylene (UHMWPE) is a biomaterial widely used in total joint replacement. In this work, the effect of two different irradiation techniques on UHMWPE is analyzed. One technique involves gamma irradiation (γ) followed by a thermal treatment, thus modifying the material bulk. The other implies swift heavy ion irradiation (SHI), which have an effect only on the near surface layers. The surface nanomechanical properties are evaluated from depth sensing indentation experiments, while changes in crystallinity and chemical structure are determined by DSC and Raman spectroscopy. The results show that even when both techniques are able to improve the UHMWPE wear behavior, the effect on other mechanical properties and molecular structure modification is different. The γ irradiated sample exhibits lower crystallinity, hardness and modulus than the pristine UHMWPE, while the SHI irradiated sample exhibits higher crystallinity and enhanced mechanical properties than the later

Effect of gamma irradiation on the friction and wear of ultrahigh molecular weight polyethylene

Science.gov (United States)

Jones, W. R.; Hady, W. F.; Crugnola, A.

1981-01-01

The effect of sterilization gamma irradiation on the friction and wear properties of ultrahigh molecular weight polyethylene (UHMWPE) sliding against stainless steel 316L in dry air at 23 C is investigated, the results to be used in the development of artificial joints which are to surgically replace diseased human joints. A pin-on-disk sliding friction apparatus is used, a constant sliding speed in the range 0.061-0.27 m/s is maintained, a normal load of 1 kgf is applied with dead weight, and the irradiation dose levels are: 0, 2.5, and 5.0 Mrad. Wear and friction data and conditions for each of the ten tests are summarized, and include: (1) wear volume as a function of the sliding distance for the irradiation levels, (2) incremental wear rate, and (3) coefficient of friction as a function of the sliding distance. It is shown that (1) the friction and wear properties of UHMWPE are not significantly changed by the irradiation doses of 2.5 and 5.0 Mrad, (2) the irradiation increases the amount of insoluble gel as well as the amount of low molecular weight material, and (3) after run-in the wear rate is either steady or gradually decreases as a function of the sliding distance.

Effect of gamma irradiation on linear low density polyethylene/magnesium hydroxide/sepiolite composite

International Nuclear Information System (INIS)

Shafiq, Muhammad; Yasin, Tariq

2012-01-01

Radiation crosslinking is generally used to improve the thermo-mechanical properties of the composites. A study has been carried out to investigate the effect of gamma radiation on the thermo-mechanical properties of linear low density polyethylene containing magnesium hydroxide (MH) and sepiolite (SP) as non-halogenated flame retardant additives. The developed composites are irradiated at different doses upto maximum of 150 kGy. Infrared spectra of the irradiated composites reveal the reduction in the intensity of O-H band with increase in the absorbed doses, thus indicates a distinct structural change in MH at higher doses. The thermogravimetric analysis results of unirradiated and composites irradiated at low doses (≤75 kGy) show two steps weight loss, which is changed to single step at higher doses with lower thermal stability. The melting temperature (T m ) and crystallization temperature (T c ) of irradiated composites are lowered with irradiation whereas Vicat softening temperature (VST) is increased. The increasing trend in gel content with increase in the absorbed dose confirms the presence of crosslinked network. The mechanical properties, results show significant improvement in the modulus of irradiated composites. The results also confirm that MH gradually loses its OH functionality with irradiation. - Highlights: → We have studied the effect of γ radiation on LLDPE containing Mg(OH) 2 and sepiolite. → IR spectra of the irradiated composites show reduction in the intensity of O-H band. → Reduction in OH band show a distinct structural change in Mg(OH) 2 at higher doses. → TGA results show two steps weight loss at low doses and one step at higher doses. → These results confirm that MH gradually loses its OH functionality with irradiation.

Solid-phase photocatalytic degradation of polyethylene-goethite composite film under UV-light irradiation

International Nuclear Information System (INIS)

Liu, G.L.; Zhu, D.W.; Liao, S.J.; Ren, L.Y.; Cui, J.Z.; Zhou, W.B.

2009-01-01

A novel photodegradable polyethylene-goethite (PE-goethite) composite film was prepared by embedding the goethite into the commercial polyethylene. The degradation of PE-goethite composite films was investigated under ultraviolet light irradiation. The photodegradation activity of the PE plastic was determined by monitoring its weight loss, scanning electron microscopic (SEM) analysis and FT-IR spectroscopy. The weight of PE-goethite (1 wt%) sample steadily decreased and led to the total 16% reduction in 300 h under UV-light intensity for 1 mW/cm 2 . Through SEM observation there were some cavities around the goethite powder in the composite films, but there were few changes except some surface chalking phenomenon in pure PE film. The degradation rate could be controlled by changing the concentration of goethite particles in PE plastic. The degradation of composite plastic initiated on PE-goethite interface and then extended into polymer matrix induced by the diffusion of the reactive oxygen species generated on goethite particle surface. The photocatalytic degradation mechanism of the composite films was briefly discussed.

Real World SharePoint 2007 Indispensable Experiences From 16 MOSS and WSS MVPs

CERN Document Server

Hillier, Scot; Buenz, Adam; Connell, Andrew; Draper, Stacy; Solier Grinda, Luis Du; Klindt, Todd; Medero, Jason; Miller, Dustin; Perran, Shane; Poelmans, Joris; Solomon, Heather; Swan, Nick; Tielens, Jan; Walsh, Mike; Young, Shane

2011-01-01

Microsoft recognizes key individuals who contribute significantly to the community of technologists through the Microsoft Most Valuable Professional (MVP) award. These individuals are active authors, speakers, bloggers, and innovators. They are also skilled network engineers, developers, trainers, designers, and architects. In the SharePoint community, these MVPs are recognized for their expertise in either Windows SharePoint Services (WSS) or Microsoft Office SharePoint Server (MOSS). This book represents the efforts of 16 MVPs in the SharePoint community to present core areas of SharePoint 2

Influence Of Gamma Irradiation On Mechanical And Thermal Properties Of Waste Polyethylene / Nitrile Butadiene Rubber Blend

International Nuclear Information System (INIS)

Aly, R.O.

2012-01-01

Gamma irradiation radical-radical interaction crosslinking of elastomers and thermoplastic is a special type of crosslinking technique that has gained importance over conventional chemical crosslinking method as process is fast, pollution free and simple. In this study, a blend polymer, based on waste polyethylene and nitrile butadiene rubber, has been irradiated with gamma rays then mechanically and thermally investigated at varying NBR content. FTIR and SEM techniques were used in addition to the swelling behaviour by toluene solvent to emphasize the blend formation. The mechanical properties like tensile strength, elongation at break and modulus at different elongations were studied and compared with those of non-irradiated ones. A relatively low radiation dose was found effective in improving the level of mechanical properties. Differential scanning calorimeter and thermogravimetric analysis were used to study the thermal characteristics of the irradiated polymer. Enhancement in thermal stability has been observed for higher NBR containing blends and via radiation-induced crosslinking up to ≅ 50 kGy

Gamma irradiation effects in low density polyethylene

International Nuclear Information System (INIS)

Ono, Lilian S.; Scagliusi, Sandra R.; Cardoso, Elisabeth E.L.; Lugao, Ademar B.

2011-01-01

Low density polyethylene (LDPE) is obtained from ethylene gas polymerization, being one of the most commercialized polymers due to its versatility and low cost. It's a semi-crystalline polymer, usually inactive at room temperature, capable to attain temperatures within a 80 deg C - 100 deg C range, without changing its physical-chemical properties. LDPE has more resistance when compared to its equivalent High Density Polyethylene (HDPE). LDPE most common applications consist in manufacturing of laboratory materials, general containers, pipes, plastic bags, etc. Gamma radiation is used on polymers in order to modify mechanical and physical-chemical features according to utility purposes. This work aims to the study of gamma (γ) radiation interaction with low density polyethylene to evaluate changes in its physical-chemical properties. Polymer samples were exposed to 5, 10, 15, 20 and 30kGy doses, at room temperature. Samples characterization employed Thermal Analysis, Melt Flow Index, Infrared Spectroscopy and Swelling tests. (author)

Organic materials irradiated at very low temperature and at different stopping powers: examples of polyethylene and of cyclohexane molecules trapped in matrix; Materiaux organiques irradies a tres basse temperature et a differents pouvoirs d'arret: cas du polyethylene et des molecules de cyclohexane isolees en matrice

Energy Technology Data Exchange (ETDEWEB)

Melot, M

2003-10-15

This thesis concerns the formation mechanisms of defects created in organic materials during irradiation under vacuum, at very low temperature and at different electronic stopping powers. Analysis have been realised by infrared spectroscopy. The first part concerns polyethylene. Irradiating at 8 K allows to dissociate the direct irradiation effects (in cage reactions) and the radical recombination effects. According to the considered chemical groups, the radical mobility leads to very different changes for the formation radiochemical yields. The second part concerns the irradiation of cyclohexane molecules trapped in a solid argon matrix. We evaluate the contribution of intermolecular and intramolecular reactions. The intermolecular reactions have limited consequences when using low ionising radiations but are crucial for heavy ion irradiations. (author)

Gamma irradiation effects on the grafting of low-density polyethylene with diethyl maleate

International Nuclear Information System (INIS)

Sanchez, Y.; Albano, C.; Karam, A.; Perera, R.; Silva, P.; Gonzalez, J.

2005-01-01

In this work, a low-density polyethylene (LDPE) was grafted with diethyl maleate (DEM) using gamma-rays from a Cobalt-60 source at different absorbed doses and monomer concentrations between 5 and 30 wt.%. This process was carried out in a decalin solution at 10 w/v% to obtain a homogeneous dispersion of the monomer into the polyethylene matrix. It was found that the grafting degree increases with the absorbed doses, as a consequence of the increased amount of energy given to the system, which made the grafting process more favorable. The grafting degree also increases with the concentration of DEM, because a higher concentration makes the insertion easier due to the increased availability of the free monomer. The highest grafting degree was obtained at 200 kGy of absorbed dose and with 30 wt.% of DEM. The melt flow index (MFI) values showed a decreasing trend as the absorbed dose was increased. This fact reveals that crosslinking and grafting are taking place simultaneously, this behavior being remarkable at higher irradiation doses. The results from thermogravimetric analysis (TGA) showed that the initial degradation temperatures remained almost unchanged with the absorbed dose

Influence of ionizing irradiation in air and nitrogen for sterilization of surgical grade polyethylene for implants

International Nuclear Information System (INIS)

Streicher, R.M.

1988-01-01

The influence of the atmosphere and the applied dose during ionizing radiation treatment on selected properties of ultra high molecular weight polyethylene (UHMWPE) have been investigated. A linear correlation between extinction coefficient and applied doses in air from 6 to 125 kGy was found, while oxidation was not linear with irradiation in nitrogen. Bacteria survival rate shows a necessary minimum dose of 15 kGy for assured sterility of the product. Post reaction of latent free radicals in UHMWPE created during irradiation, which react or recombine time- and environment dependent, has also been investigated after storage of UHMWPE-films in air and nitrogen at 21 0 C and in water at body temperature 37 0 C for up to nine months. Results show that the properties of UHMWPE after radiation-sterilization change depending on time, the absorbed dose, the atmosphere where irradiation took place and the environment of storage. UHMWPE, which mainly crosslinks during irradiation degrades by an oxidation process after sterilizing when stored in air and even more in water at body temperature. So irradiation and storage in nitrogen before implantation in the human body is beneficial. (author)

Graft copolymerization of water soluble mixed monomers onto polyethylene by the pre-irradiation method

International Nuclear Information System (INIS)

Long Fu; Tang Liming; Zhao Jin; Gao Zhenyong

1993-01-01

Grafting of water soluble mixed monomers of acrylic acid (AA)/acrylamide (Am) and acrylic acid/methacrylic acid (MA) onto polyethylene film by the pre-irradiation grafting method was investigated. The results showed that the grafting proceeded successfully with the adding of ferric salt in the solution. In the case of AA/Am system, a synergistic effect was noticed. In the case of AA/MA system, the graft percent increased with the increase in the concentration of MA in the feed ratio. Furthermore, the effects of monomer concentration, radiation dose and temperature on the grafting were also studied

Conversion of alkyl radicals to allyl radicals in irradiated single crystal mats of polyethylene

International Nuclear Information System (INIS)

Fujimura, T.; Hayakawa, N.; Kuriyama, I.

1978-01-01

The decay of alkyl radicals, the conversion of alkyl radicals to allyl radicals and the trapping of allyl radicals in irradiated single crystal mats of polyethylene have been studied by electron spin resonance (e.s.r.). It has been suggested that in the crystal core alkyl radicals react with trans-vinylene double bonds and are converted into trans-vinylene allyl radicals; at the crystal surface, alkyl radicals react with vinyl end groups and are converted into allyl radicals with vinyl end groups. The decay of radical pairs and the formation of trans-vinylene double bonds are discussed. (author)

Organic materials irradiated at very low temperature and at different stopping powers: examples of polyethylene and of cyclohexane molecules trapped in matrix

International Nuclear Information System (INIS)

Melot, M.

2003-10-01

This thesis concerns the formation mechanisms of defects created in organic materials during irradiation under vacuum, at very low temperature and at different electronic stopping powers. Analysis have been realised by infrared spectroscopy. The first part concerns polyethylene. Irradiating at 8 K allows to dissociate the direct irradiation effects (in cage reactions) and the radical recombination effects. According to the considered chemical groups, the radical mobility leads to very different changes for the formation radiochemical yields. The second part concerns the irradiation of cyclohexane molecules trapped in a solid argon matrix. We evaluate the contribution of intermolecular and intramolecular reactions. The intermolecular reactions have limited consequences when using low ionising radiations but are crucial for heavy ion irradiations. (author)

BOF4WSS : a business-oriented framework for enhancing web services security for e-business

OpenAIRE

Nurse, Jason R. C.; Sinclair, Jane

2009-01-01

When considering Web services' (WS) use for online business-to-business (B2B) collaboration between companies, security is a complicated and very topical issue. This is especially true with regard to reaching a level of security beyond the technological layer, that is supported and trusted by all businesses involved. With appreciation of this fact, our research draws from established development methodologies to develop a new, business-oriented framework (BOF4WSS) to guide e-businesses in def...

Investigation of the interaction of copper(II) oxide and electron beam irradiation crosslinkable polyethylene

International Nuclear Information System (INIS)

Bee, Soo-Tueen; Sin, Lee Tin; Ratnam, C.T.; Haraveen, K.J.S.; Tee, Tiam-Ting; Rahmat, A.R.

2015-01-01

In this study, the effects of electron beam irradiation on the properties of copper(II) oxide when added to low-density polyethylene (LDPE) blends were investigated. It was found that the addition of low loading level of copper(II) oxide (⩽2 phr) to LDPE results in significantly poorer gel content and hot set results. However, the incorporation of higher loading level of copper(II) oxide (⩾3 phr) could slightly increase the degree of crosslinking in all irradiated LDPE composites. This is due to the fact that higher amounts of copper(II) oxide could slightly induce the formation of free radicals in LDPE matrix. Besides, increasing irradiation doses was also found to gradually increase the gel content of LDPE composites by generating higher amounts of free radicals. As a consequence, these higher amounts of free radicals released in the LDPE matrix could significantly increase the degree of crosslinking. The addition of copper(II) oxide could reduce the tensile strength and fracture strain (elongation at break) of LDPE composites because of poorer interfacial adhesion effect between copper(II) oxide particles and LDPE matrix. Meanwhile, increasing irradiation doses on all copper(II) oxide added LDPE composites could marginally increase the tensile strength. In addition, increasing irradiation dose could enhance the thermal stability of LDPE composites by increasing the decomposition temperature. The oxidation induction time (OIT) analysis showed that, because of the crosslinking network in the copper(II) oxide added LDPE composites, oxidation reaction is much delayed.

Investigation of the interaction of copper(II) oxide and electron beam irradiation crosslinkable polyethylene

Energy Technology Data Exchange (ETDEWEB)

Bee, Soo-Tueen, E-mail: direct.beest@gmail.com [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin, E-mail: direct.tinsin@gmail.com [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Haraveen, K.J.S.; Tee, Tiam-Ting [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2015-10-01

In this study, the effects of electron beam irradiation on the properties of copper(II) oxide when added to low-density polyethylene (LDPE) blends were investigated. It was found that the addition of low loading level of copper(II) oxide (⩽2 phr) to LDPE results in significantly poorer gel content and hot set results. However, the incorporation of higher loading level of copper(II) oxide (⩾3 phr) could slightly increase the degree of crosslinking in all irradiated LDPE composites. This is due to the fact that higher amounts of copper(II) oxide could slightly induce the formation of free radicals in LDPE matrix. Besides, increasing irradiation doses was also found to gradually increase the gel content of LDPE composites by generating higher amounts of free radicals. As a consequence, these higher amounts of free radicals released in the LDPE matrix could significantly increase the degree of crosslinking. The addition of copper(II) oxide could reduce the tensile strength and fracture strain (elongation at break) of LDPE composites because of poorer interfacial adhesion effect between copper(II) oxide particles and LDPE matrix. Meanwhile, increasing irradiation doses on all copper(II) oxide added LDPE composites could marginally increase the tensile strength. In addition, increasing irradiation dose could enhance the thermal stability of LDPE composites by increasing the decomposition temperature. The oxidation induction time (OIT) analysis showed that, because of the crosslinking network in the copper(II) oxide added LDPE composites, oxidation reaction is much delayed.

Influence of gamma irradiation on mechanical and thermal properties of waste polyethylene/nitrile butadiene rubber blend

Directory of Open Access Journals (Sweden)

Raouf O. Aly

2016-11-01

Full Text Available Gamma irradiation radical–radical interaction crosslinking of elastomers and thermoplastic is a special type of crosslinking technique that has gained importance over conventional chemical crosslinking method as process is fast, pollution free, and simple. In this work a blend polymer, based on waste polyethylene and nitrile butadiene rubber, has been irradiated with gamma-rays, mechanically and thermally investigated at varying NBR content. FTIR and SEM techniques were used in addition to the swelling behavior to emphasize the blend formation. Mechanical properties like tensile strength, elongation at break and modulus at different elongations were studied and compared with those of unirradiated ones. A relatively low-radiation dose was found effective in improving the level of mechanical properties. Differential scanning calorimeter and thermogravimetric analysis were used to study the thermal characteristics of the irradiated polymer. Enhancement in thermal stability has been observed for higher NBR containing blends and via radiation-induced crosslinking up to ≈50 kGy.

Radiation effect on polyethylene tube operational properties

International Nuclear Information System (INIS)

Kagan, D.F.; Kantor, L.A.; Sokolov, I.A.; Pogrebetskij, G.E.; Perlova, N.A.; Chumakov, V.V.

1975-01-01

The operational properties (stability on prolonged usage and creeping) were determined for pressure pipes made of high-density and low-density polyethylene subjected to γ-radiation. The dependence of the period up to the breaking point on the radiation dosage was extreme in character, with a maximum being near 25 Mrad. With an increase in the irradiation dosage the character of the breaking changes from plastic (at 0-15 Mrad) to brittle (at higher dosages). The plots of creepage, indepent from the amount of radiation, can be described by logarithmic equation epsilon=epsilonsub(0)+K lgt (where, epsilon-deformation of creepage, %; epsilonsub(0)- and K - creepage constants). Therefore creepage can be considered as a criterion determining the carrying capacity of the γ-irradiated polyethylene. It was established that only radiation-grafted high-density polyethylene is suitable for hot water supply pipes

Thermogravimetric studies of the thermo-oxidative stability of irradiated and unirradiated polyethylene. 2. Combined antioxidants

Energy Technology Data Exchange (ETDEWEB)

Novakovic, L; Gal, O; Markovic, V; Stannett, V T

1985-01-01

In part one of this series the effects of a phenolic, an amine and a thioester antioxidant on the thermo-oxidative stability of irradiated and unirradiated low-density polyethylene was reported. In this paper the effects of combined phenolic and thioester stabilizers are described. Isothermal thermogravimetric analysis was used to study the systems. Pronounced synergism was observed with the induction periods, the time when the initial weight loss begins and the 5% weight loss. At about 50% of each stabilizer increases greater than twofold were observed both with the unirradiated and irradiated polymers. The rate constants for oxygen uptake were decreased. However, the rates of degradation at 5% weight loss fell between the values of the two pure stabilizers with no pronounced synergism in either case. In the absence of oxygen little effect of either antioxidant or their mixtures was observed. The corresponding activation energies were somewhat higher, however, with the irradiated samples containing antioxidants. Dynamic thermogravimetry was used for this study. A kinetic analysis indicated that there were somewhat different modes of degradation at lower- and higher-temperature ranges. (author).

Radiation modification and interaction mechanism of polypropylene and polyethylene by protons and electrons

International Nuclear Information System (INIS)

Wang Guanghou

1988-10-01

A systematic investigation of radiation effects on isotactic polypropylene (PP) and low-density polyethylene (PE) films by protons and electrons is reported. Electrons can make polyethylene cross-linked and polypropylene crached while protons can improve the PP mechanical properties and deteriorate polyethylene with increasing the irradiation dose. The structural analysis shows that conversion between α and β phases occurs and the crystallinity remains constant in the electron-irradiated polypropylene whereas the network structure is formed by allyl-type radicals in the e - -irradiated polyethylene. The infrared spectra indicate that conformational changes have taken place in the polypropylene under proton bombardment, such as the transition from an ordered to a disordered state in the crystalline region, the formation of double bonds as well as trans-conformations. This leads to the cross-linking between macromolecules of polypropylene at the proper irradiation doses, thus enhancing its mechanical properties. The cross-linking of polypropylene by proton bombardment observed and its properties may have some potential applications

Changes in mechanical properties due to gamma irradiation of high-density polyethylene (HDPE

Directory of Open Access Journals (Sweden)

S. S. Cota

2007-06-01

Full Text Available This paper presents an experimental analysis of the effect of dose and dose rate parameters during gamma irradiation of high-density polyethylene (HDPE samples. Considerations concerning the influence of these parameters on HDPE mechanical strength properties as a result of the predominance of oxidative degradation or of cross-linking are presented. The experimental results show an improvement of HDPE mechanical strength as dose increases, indicating the predominance of cross-linking over oxidative degradation and that lower doses are necessary to obtain a similar change in resistance parameters when radiation is applied at lower dose rates, showing that gamma radiation affects the HDPE in a more efficient way at lower dose rates.

Changes in mechanical properties due to gamma irradiation of high-density polyethylene (HDPE)

International Nuclear Information System (INIS)

Cota, S.S.; Vasconcelos, V.; Senne Junior, M.; Carvalho, L.L.; Rezende, D.B.; Correa, R.F.

2007-01-01

This paper presents an experimental analysis of the effect of dose and dose rate parameters during gamma irradiation of high-density polyethylene (HDPE) samples. Considerations concerning the influence of these parameters on HDPE mechanical strength properties as a result of the predominance of oxidative degradation or of cross-linking are presented. The experimental results show an improvement of HDPE mechanical strength as dose increases, indicating the predominance of cross-linking over oxidative degradation and that lower doses are necessary to obtain a similar change in resistance parameters when radiation is applied at lower dose rates, showing that gamma radiation affects the HDPE in a more efficient way at lower dose rates. (author)

Radiolysis effects on polyethylene terephtalate

International Nuclear Information System (INIS)

Zaharescu, Traian; Ciuprina, Florin

2005-01-01

The effects of high energy exposure of polyethylene terephtalate, the main electrical insulator for the conduction bars in alternative current generators, is presented. For comparison γ-irradiation was performed in distilled water and air at various doses, up to about 200 kGy. The dependencies of current on time for radiation processed PET sheets allow to depict the variation in the resistivity values as a measure of chemical changes in polyethylene terephtalate macromolecules. The comparison between the evolution of currents in irradiated specimens and spectral analysis bring about a light on the accumulation of radiolysis product in PET matrix. The high energy exposure of PET in air causes an increase of final value of current, while similar experiments in water produces a contrary effect. Some considerations of degradation mechanism are presented

The influence of nano silica particles on gamma-irradiation ageing of elastomers based on chlorosulphonated polyethylene and acrylonitrile butadiene rubber

Science.gov (United States)

Marković, G.; Marinović-Cincović, M.; Tanasić, Lj.; Jovanović, V.; Samaržija-Jovanović, S.; Vukić, N.; Budinski-Simendić, J.

2011-12-01

The goal of this work was to study gamma irradiation ageing of rubber blends based on acrylonitrile butadiene rubber (NBR) and chlorosulphonated polyethylene rubber (CSM) reinforced by silica nano particles. The NBR/CSM compounds (50: 50, w/w) filled with different content of filler (0-100 phr) were crosslinked by sulfur. The vulcanization characteristics were assessed using the rheometer with an oscillating disk. The vulcanizates were prepared in a hydraulic press. The obtained materials were exposed to the different irradiation doses (100, 200, 300 and 400 kGy). The mechanical properties (hardness, modulus at 100% elongation, tensile strength and elongation at break) and swelling numbers were assessed before and after gamma irradiation ageing.

Combined effect of solvents and gamma irradiation on the infrared absorption spectra of polyethylene terephthalate

International Nuclear Information System (INIS)

Rabie, S.M.; ElBially, A.; Elshourbaguie, S.

1991-01-01

The combined effect of solvents and gamma irradiation on the intensities of infrared absorption bands of polyethylene terephthalate, particularly the bands sensitive to conformational changes, were studied. The results revealed that solvent treatment of PET results in significant changes in the intensities of its infrared absorption bands and the exposure of PET to gamma radiation in the presence of solvents helps in the appearance of the two bands at 1550 and 1630 cm . Also, the combined effect of solvents and gamma irradiation on the intensities of the absorption bands is greater than the effect of each agent alone. The extent of the induced changes depends on the nature of solvent and the applied dosage. Further more, for any given solvent or dosage, the rate of change of the intensities of the trans band is not equal to that of the gauche bands.3 fig

Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

Energy Technology Data Exchange (ETDEWEB)

Ferreto, H. F. R., E-mail: hferreto@ipen.br, E-mail: ana-feitoza@yahoo.com.br; Oliveira, A. C. F., E-mail: hferreto@ipen.br, E-mail: ana-feitoza@yahoo.com.br; Parra, D. F., E-mail: dfparra@ipen.br, E-mail: ablugao@ipen.br; Lugão, A. B., E-mail: dfparra@ipen.br, E-mail: ablugao@ipen.br [Center of Chemistry and Environment, Institute of Energy and Nuclear Research - IPEN (Brazil); Gaia, R., E-mail: renan-gaia7@hotmail.com [Faculdades Oswaldo Cruz (Brazil)

2014-05-15

The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of {sup 60}Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

Preparation of nanocomposite γ-Al2O3/polyethylene separator crosslinked by electron beam irradiation for lithium secondary battery

Science.gov (United States)

Nho, Young-Chang; Sohn, Joon-Yong; Shin, Junhwa; Park, Jong-Seok; Lim, Yoon-Mook; Kang, Phil-Hyun

2017-03-01

Although micro-porous membranes made of polyethylene (PE) offer excellent mechanical strength and chemical stability, they exhibit large thermal shrinkage at high temperature, which causes a short circuit between positive and negative electrodes in cases of unusual heat generation. We tried to develop a new technology to reduce the thermal shrinkage of PE separators by introducing γ-Al2O3 particles treated with coupling agent on PE separators. Nanocomposite γ-Al2O3/PE separators were prepared by the dip coating of polyethylene(PE) separators in γ-Al2O3/poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP)/crosslinker (1,3,5-trially-1,3,5-triazine-2,4,6(1 H,3 H,5 H)-trione (TTT) solution with humidity control followed by electron beam irradiation. γ-Al2O3/PVDF-HFP/TTT (95/5/2)-coated PE separator showed the highest electrolyte uptake (157%) and ionic conductivity (1.3 mS/cm). On the basis of the thermal shrinkage test, the nanocomposite γ-Al2O3/PE separators containing TTT irradiated by electron beam exhibited a higher thermal resistance. Moreover, a linear sweep voltammetry test showed that the irradiated nanocomposite γ-Al2O3/PE separators have electrochemical stabilities of up to 5.0 V. In a battery performance test, the coin cell assembled with γ-Al2O3/PVDF-HFP/TTT-coated PE separator showed excellent discharge cycle performance.

Gamma radiation effects on the rheological properties of high and low density polyethylenes

International Nuclear Information System (INIS)

Rangel-Nafaile, C.; Garcia-Rejon, A.; Garcia Leon, A.

1986-01-01

High energy radiation of polymeric materials is a topic of considerable interest from commercial and scientific points of view. Within an inert atmosphere, irradiation of polyethylene yields a crosslinking effect with a consequent improvement in its mechanical properties in comparison to the virgin materials. Additionally, if irradiated specimens are melted and recrystallized, the radiation-induced crosslinking hinders their crystalline growth altering dramatically their flow properties such as the elasticity. This work portrays the effects of the gamma radiation on the rheological properties of high and low density polyethylenes manufactured by PEMEX and analyzes the implications of theoretical results derived from the Acierno's model when it is implemented with the rheological properties of high energy irradiated polyethylenes. (author)

Electron beam irradiation process applied to primary and secondary recycled high density polyethylene

International Nuclear Information System (INIS)

Cardoso, Jéssica R.; Moura, Eduardo de; Geraldo, Áurea B.C.

2017-01-01

Plastic bags, packaging and furniture items are examples of plastic utilities always present in life. However, the end-of-life of plastics impacts the environment because of this ubiquity and also often their high degradation time. Recycling processes are important in this scenario because they offer many solutions to this problem. Basically, four ways are known for plastic recycling: primary recycling, which consists in re-extrusion of clean plastic scraps from a production plant; secondary recycling, that uses end-of-life products that generally are reduced in size by extrusion to obtain a more desirable shape for reprocessing (pellets and powder); tertiary recover which is related to thermo-chemical methods to produce fuels and petrochemical feedstock; and quaternary route, that is related to energy recovery and it is done in appropriate reactors. In this work, high density polyethylene (HDPE) was recovered to simulate empirically the primary and secondary recycling ways using materials which ranged from pristine to 20-fold re-extrused materials. The final 20-fold recycled thermoplastic was irradiated in an electron beam accelerator under a dose rate of 22.4 kGy/s and absorbed doses of 50 kGy and 100 kGy. The characterization of HDPE in distinct levels of recovering was performed by infrared spectroscopy (FTIR) and thermogravimetric degradation. In the HDPE recycling, degradation and crosslinking are consecutive processes; degradation is very noticeable in the 20-fold recycled product. Despite this, the 20-fold recycled product presents crosslinking after irradiation process and the post-irradiation product presents similarities in spectroscopic and thermal degradation characteristics of pristine, irradiated HDPE. These results are discussed. (author)

Electron beam irradiation process applied to primary and secondary recycled high density polyethylene

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Jéssica R.; Moura, Eduardo de; Geraldo, Áurea B.C., E-mail: ageraldo@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

Plastic bags, packaging and furniture items are examples of plastic utilities always present in life. However, the end-of-life of plastics impacts the environment because of this ubiquity and also often their high degradation time. Recycling processes are important in this scenario because they offer many solutions to this problem. Basically, four ways are known for plastic recycling: primary recycling, which consists in re-extrusion of clean plastic scraps from a production plant; secondary recycling, that uses end-of-life products that generally are reduced in size by extrusion to obtain a more desirable shape for reprocessing (pellets and powder); tertiary recover which is related to thermo-chemical methods to produce fuels and petrochemical feedstock; and quaternary route, that is related to energy recovery and it is done in appropriate reactors. In this work, high density polyethylene (HDPE) was recovered to simulate empirically the primary and secondary recycling ways using materials which ranged from pristine to 20-fold re-extrused materials. The final 20-fold recycled thermoplastic was irradiated in an electron beam accelerator under a dose rate of 22.4 kGy/s and absorbed doses of 50 kGy and 100 kGy. The characterization of HDPE in distinct levels of recovering was performed by infrared spectroscopy (FTIR) and thermogravimetric degradation. In the HDPE recycling, degradation and crosslinking are consecutive processes; degradation is very noticeable in the 20-fold recycled product. Despite this, the 20-fold recycled product presents crosslinking after irradiation process and the post-irradiation product presents similarities in spectroscopic and thermal degradation characteristics of pristine, irradiated HDPE. These results are discussed. (author)

Development of extremely low wear cross-link polyethylene for 30 years

International Nuclear Information System (INIS)

Oonishi, Hironobu; Fujita, Hiroshi; Kim, Seok-Cheol; Ito, Shigeru; Masuda, Shingo; Clarke, I.C.

2003-01-01

In this report we present our long-term developmental and clinical results with both highly cross-linked and extensively cross-linked polyethylene materials. Beginning in 1970s, we performed wear screening studies on ultra high molecular weight polyethylene (UHMWPE) (GUR412) sterilized by gamma-irradiation in air (range 0 to 10,000 kGy). From these scientific studies the 1,000 kGy dose (100 Mrad) appeared optimal, and so we began clinical use in 1971, and that continued into 1978. The radiographic wear-rates in patients with 1,000 kGy sockets, assessed by radiography, appeared 6-fold reduced compared to our standard UHMWPE sockets. Note also that we had not used any post-sterilization heat treatment for these pioneering extensively cross-linked polyethylene sockets. With clinical use now over 30 years, it was also clear that there was no adverse oxidation created by any free radicals present in our extensively cross-linked polyethylene sockets. With these encouraging clinical results, we further studied laboratory wear results with the modern UHMWPE resins, using the irradiation doses 1,000, 5,000, 10,000 and 15,000 kGy and with both saline and serum lubricants in hip simulators. These more recent studies demonstrated that the wear in extensively cross-linked polyethylene sockets was undetectable, less even than the measurement errors in the simulator techniques. It was unfortunate that the physical properties of such extensively cross-linked polyethylene sockets did not meet the current International Organization for Standardization (ISO) and American Society for Testing and Materials (ASTM) standards. Thus, despite the excellent wear performance of these materials, we decided to investigate also the properties of the 60 kGy irradiated UHMWPE. The polyethylene sheet (GUR1050) was first irradiated with 35 kGy under N2 and then heat treated to remove free radicals. The socket liners were then machined to shape and resterilized with 25 kGy under N2 gas. The

Temperature dependence of deformation vs. strength properties of radiation-crosslinked polyethylene

International Nuclear Information System (INIS)

Matusevich, Yu.I.; Krul', L.P.

1992-01-01

The authors have studied the deformation vs. strength properties of radiation-crosslinked low-density polyethylene irradiated by γ irradiation up to doses from 5.0 sm-bullet 10 4 to 1.0 sm-bullet 10 6 Gy. The authors present the elongation diagrams taken at temperatures below and above the melting point of the polymer. The authors have obtained the dependences of the breaking stress and the pre-break elongation of the polymer on the irradiation doses and the testing temperature. Based on the kinetic lifetime equation, The authors calculated the values of the activation energy for mechanical fracture and the structure-sensitive coefficient γ. The authors show that in the crystalline state the strength of radiation-crosslinked polyethylene is determined by the chemical interactions along the chain of polymer macromolecules; and in molten polyethylene, by the crosslinks between the macromolecules. 8 refs., 4 figs., 1 tab

Design and implementation of flexible TWDM-PON with PtP WDM overlay based on WSS for next-generation optical access networks

Science.gov (United States)

Wu, Bin; Yin, Hongxi; Qin, Jie; Liu, Chang; Liu, Anliang; Shao, Qi; Xu, Xiaoguang

2016-09-01

Aiming at the increasing demand of the diversification services and flexible bandwidth allocation of the future access networks, a flexible passive optical network (PON) scheme combining time and wavelength division multiplexing (TWDM) with point-to-point wavelength division multiplexing (PtP WDM) overlay is proposed for the next-generation optical access networks in this paper. A novel software-defined optical distribution network (ODN) structure is designed based on wavelength selective switches (WSS), which can implement wavelength and bandwidth dynamical allocations and suits for the bursty traffic. The experimental results reveal that the TWDM-PON can provide 40 Gb/s downstream and 10 Gb/s upstream data transmission, while the PtP WDM-PON can support 10 GHz point-to-point dedicated bandwidth as the overlay complement system. The wavelengths of the TWDM-PON and PtP WDM-PON are allocated dynamically based on WSS, which verifies the feasibility of the proposed structure.

High-density polyethylene dosimetry by transvinylene FTIR analysis

DEFF Research Database (Denmark)

McLaughlin, W.L.; Silverman, J.; Al-Sheikhly, M.

1999-01-01

and electrons. The useful dose range of 0.053 cm thick high-density polyethylene film (rho = 0.961 g cm(-3); melt index = 0.8 dg min(-1)), for irradiations by (60)Co gamma radiation and 2.0 and 0.4 MeV electron beams in deaerated atmosphere (Na gas), is about 50-10(3) kGy for FTIR transvinylene......The formation of transvinylene unsaturation, -CH=CH-, due to free-radical or cationic-initiated dehydrogenation by irradiation, is a basic reaction in polyethylene and is useful for dosimetry at high absorbed doses. The radiation-enhanced infrared absorption having a maximum at nu = 965 cm......(-l) (lambda = 10.36 mu m) is stable in air and can be measured by Fourier-transform infrared (FTIR) spectrophotometry. The quantitative analysis is a useful means of product end-point dosimetry for radiation processing with gamma rays and electrons, where polyethylene is a component of the processed product...

Study of gamma irradiated polyethylenes by temperature modulated differential scanning calorimetry

International Nuclear Information System (INIS)

Secerov, B.; Galovic, S.; Trifunovic, S.; Milicevic, D.; Suljovrujic, E.

2011-01-01

Complete text of publication follows. The various polyethylenes (PEs) and effects of high energy radiation on theirs structures were widely studied in the past using conventional Differential Scanning Calorimetry (DSC) measurements. In this work, we applied the Temperature Modulated Differential Scanning Calorimetry (TMDSC) technique in order to obtain more information about the influence of initial structural differences and gamma radiation on the evolution in structure and thermal properties of different polyethylenes. For this reason, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) samples were exposed to gamma radiation, in air, to a wide range of absorbed doses (up to 2400 kGy). The separation of the total heat flow TMDSC signal into a reversing and nonreversing part enabled to observed the low temperature enthalpy relaxation (related to the existence of the 'rigid amorphous phase') and recrystallization processes as well as to follow their and/or radiation-induced evolution of melting in a more revealing manner compared to the case of the conventional DSC. Consequently, our results indicate that TMDSC could improve the understanding of radiation-induced effects in polymers.

Measurements of Free Radical in Vitamin E-Doped Ultra-High Molecular Weight Polyethylene: Dependence on Materials Processing and Irradiation Environments

International Nuclear Information System (INIS)

Ridley, M. D.

2006-01-01

In an effort to combat oxidation of the load-bearing, polyethylene (PE) components of total hip- and knee-joint replacement devices, antioxidant such as vitamin E (α-Tocopherol (α-T)) has been introduced into polymer matrix. In this study we investigated effect of α-T on free radicals in medical grade ultra-high molecular weight polyethylene (UHMWPE), GUR 1020 resin. Since oxidation resistance depends on radical reaction, we used electron spin resonance (ESR) technique for direct detection of free radicals before and after irradiation. High concentration (20% by vol.) of α-T was used so its ESR signal (due to α-T-O degree radical) could be distinguished among the overwhelming signals due to PE radicals. Two groups of samples were investigated. In one group, samples were prepared from blends of α-T and UHMWPE powder (α-T-P), and in the second group, from compression molded blocks (α-T-B). In each group, samples were γ-irradiated in sealed packages filled with N 2 , or in open air, and free radicals were measured in open air environment as a function of time. Also included in this study were α-T, and powder resin and compression molded blocks without any α-T. Following irradiation in air, α-T-P and α-T produced identical ESR spectra showing characteristic feature of α-T-O degree radical. Absence of PE radicals in the ESR signals suggests quenching/repairing of PE radicals by α-T in presence of oxygen. However, when irradiation was performed in N 2 , ESR signals of α-T-P exhibited superimposed resonance lines due to PE and α-T-O degree radicals. Furthermore, presence of a-T or α-T-O degree radicals did not prevent subsequent oxidation of PE radicals in producing stable, oxygen-induced radicals (OIR). Post-irradiation oxidation index measured by FTIR, however, did not show any difference between these samples. Compression molded samples, with or without α-T, produced ESR spectra showing features characteristics of PE radicals only, and there was no

Shelf-life enhancement of fresh ginger rhizomes at ambient temperatures by combination of gamma-irradiation, biocontrol and closed polyethylene bag storage

International Nuclear Information System (INIS)

Mukherjee, P.K.; Thomas, P.; Raghu, K.

1995-01-01

The feasibility of a combination process involving gamma-irradiation, packing in closed polyethylene bags and biological control of fungi causing storage rot was evaluated as a means of extending the shelf-life of fresh ginger rhizomes at ambient temperatures (25–30°C). Storage in closed polyethylene bags reduced weight loss but increased sprouting and rooting, which could be prevented by gamma irradiation to 60 Gy. Rotting caused by Sclerotium rolfsii was, however, a major cause of spoilage during extended storage. Four isolates of Trichoderma sp. isolated from sclerotia of S. rolfsii infecting ginger rhizomes, one of Gliocfadium uirens, and four isolates of fluorescent Pseudomonas were tested, out of which, one isolate of Trichoderma was found to be highly effective in suppressing the growth of S. rolfsii. The efficacy of the antagonist was demonstrated under simulated market conditions using artificially inoculated rhizomes. The recommended procedure consists of dipping washed, air dried rhizomes in Trichoderma suspension (10 8 spores ml -1 ), air-drying, packing in 250 gauge LDPE bags followed by irradiation to 60 Gy. Rhizomes thus treated remained in good marketable condition for up to 2 months at ambient temperature without sprouting or significant loss of quality and less than 5% weight loss. An in vitro bioassay system was developed to demonstrate the efficacy of the antagonist to protect the cut surface of sliced rhizomes inoculated with the pathogen. The method could be used for rapid screening of antagonists

Cross-linked compared with historical polyethylene in THA: an 8-year clinical study.

Science.gov (United States)

Geerdink, Carel H; Grimm, Bernd; Vencken, Wendy; Heyligers, Ide C; Tonino, Alphons J

2009-04-01

Wear particle-induced osteolysis is a major cause of aseptic loosening in THA. Increasing wear resistance of polyethylene (PE) occurs by increasing the cross-link density and early reports document low wear rates with such implants. To confirm longer-term reductions in wear we compared cross-linked polyethylene (irradiation in nitrogen, annealing) with historical polyethylene (irradiation in air) in a prospective, randomized clinical study involving 48 patients who underwent THAs with a minimum followup of 7 years (mean, 8 years; range, 7-9 years). The insert material was the only variable. The Harris hip score, radiographic signs of osteolysis, and polyethylene wear were recorded annually. Twenty-three historical and 17 moderately cross-linked polyethylene inserts were analyzed (five patients died, three were lost to followup). At 8 years, the wear rate was lower for cross-linked polyethylene (0.088 +/- 0.03 mm/year) than for the historical polyethylene (0.142 +/- 0.07 mm/year). This reduction (38%) did not diminish with time (33% at 5 years). Acetabular cyst formation was less frequent (39% versus 12%), affected fewer DeLee and Charnley zones (17% versus 4%), and was less severe for the cross-linked polyethylene. The only revision was for an aseptically loose cup in the historical polyethylene group. Moderately cross-linked polyethylene maintained its wear advantage with time and produced less osteolysis, showing no signs of aging at mid-term followup. Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

Energy Technology Data Exchange (ETDEWEB)

Chong, E.L.; Ahmad, Ishak [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Dahlan, H.M. [Radiation Processing Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor Darul Ehsan (Malaysia); Abdullah, Ibrahim, E-mail: dia@ukm.m [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

2010-08-15

Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m{sup 2}, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

Energy Technology Data Exchange (ETDEWEB)

Asriza, Ristika O.; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Division of Inorganic and Physical Chemistry, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, 40132 (Indonesia)

2015-09-30

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

Science.gov (United States)

Asriza, Ristika O.; Arcana, I. Made

2015-09-01

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm-1 indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

Observations of radiation damage effects in paraffin and polyethylene crystals

International Nuclear Information System (INIS)

Petermann, J.; Gleiter, H.; Bochum Univ.

1973-01-01

A report is given on electron microscopic observations on n-paraffin and polyethylene monocrystals after irradiating with electrons. The observations show that the cross-links in n-paraffin monocrystals form agglomerates which preferably occur in the neighbourhood of lattice defects. In polyethylene monocrystals, the cross-links line up in long rows parallel to the [100] or [010] direction. (orig./LH) [de

The Influence of Irradiation and Accelerated Aging on the Mechanical and Tribological Properties of the Graphene Oxide/Ultra-High-Molecular-Weight Polyethylene Nanocomposites

Directory of Open Access Journals (Sweden)

Guodong Huang

2016-01-01

Full Text Available Graphene oxide/ultra-high-molecular-weight polyethylene (GO/UHMWPE nanocomposite is a potential and promising candidate for artificial joint applications. However, after irradiation and accelerated aging, the mechanical and tribological behaviors of the nanocomposites are still unclear and require further investigation. GO/UHMWPE nanocomposites were successfully fabricated using ultrasonication dispersion, ball-milling, and hot-pressing process. Then, the nanocomposites were irradiated by gamma ray at doses of 100 kGy. Finally, GO/UHMWPE nanocomposites underwent accelerated aging at 80°C for 21 days in air. The mechanical and tribological properties of GO/UHMWPE nanocomposites have been evaluated after irradiation and accelerated aging. The results indicated that the incorporation of GO could enhance the mechanical, wear, and antiscratch properties of UHMWPE. After irradiation, these properties could be further enhanced, compared to unirradiated ones. After accelerated aging, however, these properties have been significantly reduced when compared to unirradiated ones. Moreover, GO and irradiation can synergistically enhance these properties.

A study of gamma-irradiated polyethylenes by temperature modulated differential scanning calorimetry

Science.gov (United States)

Galovic, S.; Secerov, B.; Trifunovic, S.; Milicevic, D.; Suljovrujic, E.

2012-09-01

Various polyethylenes (PEs) and the effects of high-energy radiation on their structures were widely studied in the past using conventional Differential Scanning Calorimetry (DSC) measurements. In this work, we used the Temperature Modulated Differential Scanning Calorimetry (TMDSC) technique in order to obtain more information about the influence of the initial structural differences and gamma radiation on the evolution in structure and thermal properties of different polyethylenes. For this reason, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) samples were exposed to gamma radiation, in air, to a wide range of absorbed doses (up to 2400 kGy). The separation of the total heat flow TMDSC signal into a reversing and non-reversing part enabled us to observe the low-temperature enthalpy relaxation (related to the existence of the "rigid amorphous phase") and recrystallisation processes, as well as to follow their radiation-induced evolution and/or that of melting in a more revealing manner compared to the case of the conventional DSC. Consequently, our results indicate that TMDSC could improve the understanding of radiation-induced effects in polymers.

Temperature dependence of radiation effects in polyethylene

International Nuclear Information System (INIS)

Wu, G; Katsumura, Y.; Kudoh, H.; Morita, Y.; Seguchi, T.

2000-01-01

Temperature dependence of crosslinking and gas evolution under γ-irradiation was studied for high-density and low-density polyethylene samples in the 30-360degC range. It was found that crosslinking was the predominant process up to 300degC and the gel point decreased with increasing temperature. At above 300degC, however, the gel fraction at a given dose decreased rapidly with temperature and the action of radiation turned to enhance polyethylene degradation. Yields of H 2 and hydrocarbon gases increased with temperature and the compositions of hydrocarbons were dose dependent. (author)

Radiation-induced linking reactions in polyethylene

International Nuclear Information System (INIS)

Zoepfl, F.J.

1983-01-01

Three types of measurements are reported relating to chemical reactions in polyethylene induced by ionizing radiation: 1) viscometric and low-angle laser light scattering measurements to determine the effect of a radical scavenger on the yield of links; 2) calorimetric measurements to determine the effect of radiation-induced linking on the melting behavior of polyethylene; and 3) high-resolution solution carbon 13 nuclear magnetic resonance (NMR) spectrometry measurements to determine the nature of the links and the method of their formation. The NMR results present the first direct detection of radiation-induced long-chain branching (Y links) in polyethylene, and place an apparent upper limit on the yield of H-shaped crosslinks that are formed when polyethylene is irradiated to low absorbed doses. The effect of radiation-induced linking on the melting behavior of polyethylene was examined using differential scanning calorimetry (DSC). It was found that radiation-induced links do not change the heat of fusion of polythylene crystals, but decrease the melt entropy and increase the fold surface free energy per unit area of the crystals. The carbon 13 NMR results demonstrate that long-chain branches (Y links) are formed much more frequently than H-shaped crosslinks at low absorbed doses. The Y links are produced by reactions of alkyl free radicals with terminal vinyl groups in polyethylene

Radiolysis products and sensory properties of electron-beam-irradiated high-barrier food-packaging films containing a buried layer of recycled low-density polyethylene.

Science.gov (United States)

Chytiri, S D; Badeka, A V; Riganakos, K A; Kontominas, M G

2010-04-01

The aim was to study the effect of electron-beam irradiation on the production of radiolysis products and sensory changes in experimental high-barrier packaging films composed of polyamide (PA), ethylene-vinyl alcohol (EVOH) and low-density polyethylene (LDPE). Films contained a middle buried layer of recycled LDPE, while films containing 100% virgin LDPE as the middle buried layer were taken as controls. Irradiation doses ranged between zero and 60 kGy. Generally, a large number of radiolysis products were produced during electron-beam irradiation, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food 'cold pasteurization'). The quantity of radiolysis products increased with irradiation dose. There were no significant differences in radiolysis products identified between samples containing a recycled layer of LDPE and those containing virgin LDPE (all absorbed doses), indicating the 'functional barrier' properties of external virgin polymer layers. Sensory properties (mainly taste) of potable water were affected after contact with irradiated as low as 5 kGy packaging films. This effect increased with increasing irradiation dose.

Application of irradiation process for the production of thin wall wires

International Nuclear Information System (INIS)

Saito, E.

1977-01-01

The demand for thin wall crosslinked PVC or polyethylene insulated wires in Japan was about 15,000,000 dollars in value in 1975. Their annual sales in 1980 are estimated at about 40 million dollars which will account for approximately 20% of the sales of all thin wall thermoplastic insulated wires expected for the same year. A comparative study was made of the irradiation process and the chemical process for manufacture of wires with crosslinked PVC or polyethylene insulation. Having found the excellence of the irradiation process an accelerator (500 KeV, 65mA) was installed in 1973 and production was begun of several types of thin wall irradiation crosslinked PVC and polyethylene insulated wires ranging from 0.06 mm 2 to 2.0 mm 2 in the cross-sectional area of conductor, successfully putting them in extensive commercial application. This report compares the irradiation process and the chemical process, properties of several types of irradiation crosslinked PVC, and polyethylene insulated wires and their applications. (author)

Thermoluminescence glow curves of irradiated PMMA and low density polyethylene

International Nuclear Information System (INIS)

Matsuda, Koji; Nakase, Yoshiaki; Kumakiri, Yasuhito; Tsuji, Yoshio.

1985-03-01

Light emission from polymers is observed when polymers preirradiated with ionizing radiation at low temperature are heated gradually. The light emission is supposedly resulted from recombination of electrons with active centers produced in polymers or from some other processes involving charge transfer, but no definite explanation has been given at present on the thermoluminescent centers. This report describes our studies on the effects of impurities contained in polymers and pressure of ambient gases on the thermoluminescent glow curve of PMMA and low density polyethylene, which are often used for plastic film dosimeters. In the glow curve of PMMA, only one peak was observed at 110 K in an H 2 or He atmosphere at 760 Torr, but the intensity of the peak decreased with decreasing the H 2 or He gas pressure. At 10 -5 Torr H 2 or He atmosphere the peak disappered, and two sharp peaks appeared in the temperature range from 200 to 250 K. On the other hand, in the glow curve of low density polyethylene, three peaks were observed at 120 K, 180 K and 250 K in the presence of H 2 or He gas at 760 Torr. The effects of pressure of ambient gases and impurities in the polyethylene on these peaks indicate that the peak at 120 K is due to luminescent center produced on the surface or just below the surface of the matrix by collision of excited atoms or molecules of gases with polymer molecules, the peak at 120 K is originated from impurities in the matrix, and the peak at 250 0 K corresponds to luminescent center produced in polyethylene matrix. (author)

Evaluation of the radiation resistance of high-density polyethylene

International Nuclear Information System (INIS)

Dougherty, D.R.; Adams, J.W.; Barletta, R.R.

1984-03-01

Mechanical tests following gamma irradiation and creep tests during irradiation have been conducted on high-density polyethylene (HDPE) to provide data to help assess the adequacy of this material for use in high integrity containers (HICs). Two types of HDPE, a highly cross-linked rotationally molded material and a non-cross-linked blow molded material, were used in these tests. Gamma-ray irradiations were performed at several dose rates in environments of air, Barnwell and Hanford backfill soils, and ion-exchange resins. The results of tensile and bend tests on these materials following irradiation are presented along with results on creep during irradiation. 8 references, 9 figures, 2 tables

Proton irradiation effects on organic polymers

International Nuclear Information System (INIS)

Seguchi, T.; Sasuga, T.; Kawakami, W.; Hagiwara, M.; Kohno, I.; Kamitsubo, H.

1987-01-01

Organic polymer films(100 μm thickness) of polyethylene, polypropylene, polyethyleneterephtalate, and polyethersulfone were irradiated by protons of 8 MeV using a cyclotron, and their radiation effects were investigated by the changes of mechanical properties. In order to irradiate protons uniformly over wide area of polymer films, specimens were scanned during proton irradiation using a special apparatus. The absorbed dose was measured by CTA and RCD film dosimeters, and can be determined that 1 μC/cm 2 of 8 MeV proton fluence is equivalent to 54 kGy. For polyethylene and polypropylene, there was no significant difference between proton and electron irradiation for same doses. However, for polyethersulfone the decay of mechanical property was observed to be less than that of irradiation by electron. (author)

Radiolytic unsaturation decay in polyethylene. Part II--the effect of irradiation temperature, thermal history and orientation

International Nuclear Information System (INIS)

Lyons, Bernard J.

2004-01-01

The decay rate of vinyl unsaturation in high-density polyethylenes irradiated at temperatures from about 310 to 450 K, changes significantly in the melting range up to the crystalline melting point as does free radical mobility and the polymer crystallinity. However, orienting the polymer, or slow cooling or quenching from the melt, prior to irradiation, do not alter the decay process or its rate, although they do alter the rate of increase of insoluble gel and of elastic modulus in the molten state. It is suggested that, below ∼340 K, the marked deviations from a first-order decay result from the limited mobility of polymeric free radicals in the crystalline phase and from scavenging, by vinyl groups, segregated into the amorphous phase, of radiolytic hydrogen atoms (H). In the melting range, the mobility of polymeric free radicals increases as the crystallinity decreases, reducing the importance of scavenging, so vinyl decay approximates more closely to a first-order relation. In the melt, the vinyl decay relation is not changed qualitatively by H atom scavenging, but the effective vinyl concentration is lower, so the decay rate drops sharply

Permeabilization of ultraviolet-irradiated chinese hamster cells with polyethylene glycol and introduction of ultraviolet endonuclease from Micrococcus luteus

International Nuclear Information System (INIS)

Yarosh, D.B.; Setlow, R.B.

1981-01-01

Chinese hamster V-79 cells were made permeable by treatment with polyethylene glycol and then incubated with a Micrococcus luteus extract containing ultraviolet-specific endonuclease activity. This treatment introduced nicks in irradiated, but not in unirradiated, deoxyribonucleic acid. The nicks remained open for at least 3 h; there was no loss of endonuclease-sensitive sites, and no excision of dimers as measured by chromatography was detected. In addition, there was no increase in ultraviolet resistance in treated cells. This suggests that the absence of a significant amount of excision repair in rodent cells is due to the lack of both incision and excision capacity

Comparative study of two methods of analysis crystallinity, x-ray and DSC, using a linear low density polyethylene (LLDPE) injected, irradiated by gamma radiation

International Nuclear Information System (INIS)

Oliveira, Ana C.F. de; Ferreto, Helio F.R.; Parra, Duclerc F.; Lugao, Ademar B.

2015-01-01

The linear low density polyethylene (LLDPE) is a linear polymer chain with short chain branching. In this work, the LLDPE was irradiated in "6"0Co gamma source with 2000 kCi of activity, in presence of air, with doses of 5, 10, 20, 50 or 100 kGy, at about 5 kGy.h-1 dose rate, at room temperature. After irradiation, the samples were heated for 60 min at 100 deg C to promote recombination and annihilation of residual radicals. LLDPE injected and irradiated samples were characterized to identity the effects of terminal degradation, scission and crosslinking occurred in each dose. In the radiation process has changes in the crystallization and thus it is possible to compare the methods to obtain the percentage of crystallization of PELDB by DSC and X-ray. (author)

Electron beam cross-linking of natural rubber/linear-low density polyethylene blends

International Nuclear Information System (INIS)

Ahmad, A.; Mohd, D. H.; Abdullah, I.

2005-01-01

Effects of electron beam irradiation on the mechanical properties and morphological structure of natural rubber/linear-low density polyethylene blend was investigated The natural rubber/linear-low density polyethylene blend was prepared by melt blending in a Haake internal mixer at 140 d ig C , rotor speed of 50 rpm, and in 15 min Liquid natural rubber was incorporated into the blend as a compatibilizer Samples in the form of 1 mm sheets were exposed to 50-300 kGy of electron beam irradiation and analyzed for swelling index and gel content, tensile strength, and surface morphology. The result Indicated that gel content and mechanical properties of the samples increased with radiation dosage. The honey-comb structure of the surface morphology in low dosage irradiated samples slowly transformed into a continuous matrix on increasing radiation dose The variation of mechanical and physical properties was due to Increase in cross-linking density in the rubber and plastic phases and rubber-plastic Interaction on irradiation

Method to measure composition modifications in polyethylene terephthalate during ion beam irradiation

Science.gov (United States)

Abdesselam, M.; Stoquert, J. P.; Chami, S.; Djebara, M.; Chami, A. C.; Siad, M.

2009-01-01

Matter losses of polyethylene terephthalate (PET, Mylar) films induced by 1600 keV deuteron beams have been investigated in situ simultaneously by nuclear reaction analysis (NRA), deuteron forward elastic scattering (DFES) and hydrogen elastic recoil detection (HERD) in the fluence range from 1 × 10 14 to 9 × 10 16 cm -2. Volatile degradation products escape from the polymeric film, mostly as hydrogen-, oxygen- and carbon-containing molecules. Appropriate experimental conditions for observing the composition and thickness changes during irradiation are determined. 16O(d,p 0) 17O, 16O(d,p 1) 17O and 12C(d,p 0) 13C nuclear reactions were used to monitor the oxygen and carbon content as a function of deuteron fluence. Hydrogen release was determined simultaneously by H(d,d)H DFES and H(d,H)d HERD. Comparisons between NRA, DFES and HERD measurements show that the polymer carbonizes at high fluences because most of the oxygen and hydrogen depletion has already occured below a fluence of 3 × 10 16 cm -2. Release curves for each element are determined. Experimental results are consistent with the bulk molecular recombination (BMR) model.

Thermogravimetric studies on electron beam initiated grafting of triallyl cyanurate onto polyethylene

International Nuclear Information System (INIS)

Chaki, T.K.; Bhowmik, A.K.; Mukunda, P.G.; Majali, A.B.; Tikku, V.K.

1993-01-01

Low density polyethylene (LDPE) containing different levels of triallyl cyanurate (TAC) have been prepared in a Brabender Plasticorder at 120 degC. The moulded samples in the form of rectangular compression sheet were irradiated under electron beam accelerator with different irradiation doses. Thermogravimetric and derivative thermogravimetric analyses of the irradiated samples grafted with TAC have been carried out in order to explore the decomposition behaviour and kinetics of decomposition under nitrogen atmosphere. Initial decomposition temperature (Ti), temperature at which 50% weight loss takes place (T50), final decomposition temperature (Tf) and the kinetic parameters evaluated from TGA traces of samples at different radiation doses (constant TAC level) and at different levels of TAC (constant radiation dose) have been reported. The effect of radiation dose and TAC level on the grafting of TAC onto polyethylene have been explained on the basis of degradation characteristics of irradiated samples. Kinetic studies show that the degradation of the irradiated samples follow first order reaction kinetics. Activation energies of degradation have been determined using McCarty and Green's method. Activation energy of the irradiated samples increases with the increasing radiation dose and also with increasing level of TAC. (author). 3 tabs

Elaboration of recycled polyethylene foams reticulated by radiation

International Nuclear Information System (INIS)

Galicia M, M.

2000-01-01

In this work some obtained results are presented to make irradiation tests on recycled polymeric material (polyethylene) as well as mixtures of this with certain additive classes (foaming and reticulating agents) which will be used for the foams elaboration, objective of this work. Two types of foaming basically exist which are elaborated with low density polyethylene base. They are: a) the extruded and, b) the reticulated through ionizing radiation and chemically. Some of the properties that the expanded or foamed polyethylene are: flexibility, resistance, thermal stability, inter medium mechanical properties between the highly flexible foams and rigid among others. All of them determined by the cell type which conform them. Also was carried out the characterization of the obtained material contributing of this manner to diminish the quantity of solid wastes generated. (Author)

Radiation grafting of dimethylaminopropylacrylamide and dimethylaminopropylmethacrylamide onto polyethylene

Energy Technology Data Exchange (ETDEWEB)

Burillo, Guillermina; Oseguera, M.A. [UNAM, Inst. de Ciencias Nucleares, Mexico City (Mexico); Vazquez, Carmen; Castillo, L.P. del [UNAM, Inst. de Investigaciones en Materiales, Mexico City (Mexico)

1997-11-01

Radiation-induced grafting of dimethylaminopropylacrylamide and dimethylamino-propylmethacrylamide onto polyethylene films, by direct grafting of the vinyl monomers to a polymer by mutual irradiation, has been investigated. The kinetics of the reaction were studied at different irradiation temperatures, monomer concentration and dose rates of gamma rays, and the appropriate reaction conditions for graft polymerization were determined. The thermal and mechanical behavior of the grafted films by means of DMA, TMA, DSC and TGA were also investigated. (author).

Advantageous use of SSA technique to observe effects of thickness, antioxidant and oxygen in gamma irradiated low density polyethylene

Energy Technology Data Exchange (ETDEWEB)

Perez, C.J., E-mail: cjperez@fi.mdp.edu.ar [Research Institute of Material Science and Technology (INTEMA), National Research Council (CONICET), Engineering Faculty, Mar del Plata University, Av. J.B. Justo 4302, 7600 Mar del Plata (Argentina); Failla, M.D. [Planta Piloto de Ingenieria Quimica-PLAPIQUI (UNS-CONICET), Camino ' La Carrindanga' Km 7, 8000 Bahia Blanca (Argentina); Carella, J.M. [Research Institute of Material Science and Technology (INTEMA), National Research Council (CONICET), Engineering Faculty, Mar del Plata University, Av. J.B. Justo 4302, 7600 Mar del Plata (Argentina)

2012-06-20

Highlights: Black-Right-Pointing-Pointer Information from successive self-nucleation and annealing technique is analyzed. Black-Right-Pointing-Pointer Oxygen and antioxidants reduce crosslinking efficiency by reaction with free radicals. Black-Right-Pointing-Pointer Recognizable differences are obtained in samples irradiated at different atmospheres. - Abstract: Information obtained from successive self-nucleation and annealing (SSA) technique is analyzed, paying special attention to the observable effects of samples thickness and antioxidant and oxygen concentrations. Molecular structure changes for low density polyethylene (LDPE) samples, irradiated under three different atmospheres for doses between 33 and 222 kGy were analyzed, with emphasis on the changes of longer polymethylene crystallizable lengths. Antioxidant and oxygen concentrations were varied for samples of different thickness to study the effects on degradation. The changes in the molecular structure were followed simultaneously by SSA and Infrared spectroscopy (FTIR) via carbonyl group concentration. Preliminary quantifications of the SSA technique sensitivity are also advanced.

The influence of freeze drying and ϒ-irradiation in pre-clinical studies of flurbiprofen polymeric nanoparticles for ocular delivery using D-(+-trehalose and polyethylene glycol

Directory of Open Access Journals (Sweden)

Ramos Yacasi GR

2016-08-01

Full Text Available Gladys Rosario Ramos Yacasi, María Luisa García López, Marta Espina García, Alexander Parra Coca, Ana Cristina Calpena Campmany Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, University of Barcelona, Barcelona, Spain Abstract: This study investigated the suspension of poly(ε-caprolactone nanoparticles as an ocular delivery system for flurbiprofen (FB-PεCL-NPs in order to overcome the associated problems, such as stability, sterility, tolerance, and efficacy, with two different FB-PεCL-NP formulations. The formulations were stabilized with poloxamer 188 (1.66% and 3.5% and submitted individually for freeze-drying and γ-irradiation with polyethylene glycol 3350 (PEG3350 and d-(+-trehalose (TRE. Both formulations satisfied criteria according to all physicochemical parameters required for ocular pharmaceuticals. The FB-PεCL-NP formulations showed non-Newtonian behavior and sustained drug release. Ex vivo permeation analysis using isolated ocular pig tissues suggested that the presence of PEG3350 results in a reduction of FB transcorneal permeation. Moreover, TRE improved the penetration of FB across the cornea, especially after γ-irradiation. In addition, both formulations did not show a significant affinity in increasing FB transscleral permeation. Both formulations were classified as nonirritating, safe products for ophthalmic administration according to hen’s egg test-chorioallantoic membrane and Draize eye test. Furthermore, an in vivo anti-inflammatory efficacy test showed that irradiated FB-PεCL-NPs prepared with PEG3350 (IR-NPsPEG have longer anti-inflammatory effects than those presented with irradiated FB-PεCL-NPs prepared with TRE (IR-NPsTRE. IR-NPsPEG showed a suitable physical stability after an aqueous reconstitution over .30 days. This study concludes that both formulations meet the Goldman’s criteria and demonstrate how irradiated nanoparticles, with innovative permeation characteristics

Chemical and physical change of packing materials for food induced by γ-ray irradiation

International Nuclear Information System (INIS)

Kawamura, Yoko; Sugita, Takiko; Yamada, Takashi

1997-01-01

28 kinds of antioxidants and UV-absorbents of synthetic resin with a kind of addition agent were stable by 30 kGy of irradiation. When polyethylene sheet incorporated with them were irradiated, amounts of many kinds of antioxidants largely decreased. They might be decomposed by reacting with radicals and peroxides in polymer produced by irradiation. Accordingly, they acted effectively to reduce deterioration of polymer. But UV-absorbent was not changed by irradiation. The addition agents of polyethylene sheet were not eluted by pseudo-food aqueous solvent independent on irradiation. However, on pseudo-fatty food solvent, amount of eluate decreased. So that, eluate of antioxidant and UV-absorbent in polyethylene was decreased by γ-ray irradiation which produced good effects on food hygiene. (S.Y.)

Radiation effects on residual voltage of polyethylene films

International Nuclear Information System (INIS)

Kyokane, Jun; Park, Dae-Hee; Yoshino, Katsumi.

1986-01-01

It has recently been pointed out that diagnosis of deterioration in insulating materials for electric cables used in nuclear power plants and outer space (communications satellite in particular) can be effectively performed based on measurements of residual voltage. In the present study, polyethylene films are irradiated with γ-rays or electron beam to examine the changes in residual voltage characteristics. Irradiation of electron beam and γ-rays are carried out to a dose of 0 - 90 Mrad and 0 - 100 Mrad, respectively. Measurements are made of the dependence of residual voltage on applied voltage, electron beam and γ-ray irradiation, annealing temperature and annealing time. Results show that carriers, which are once trapped after being released from the electrode, move within the material after the opening of the circuit to produce resiual voltage. The residual voltage increases with increasing dose of electron beam or γ-ray and levels off at high dose. Residual voltage is increased about several times by either electron beam or γ-rays, but electron beam tends to cause greater residual voltage than γ-ray. Polyethylene films irradiated with electron beam can recover upon annealing. It is concluded from observations made that residual voltage has close relations with defects in molecular structures caused by radiations, particularly the breaking of backbone chains and alteration in superstructures. (Nogami, K.)

Poly(ethylene glycol) dicarboxylate/poly(ethylene oxide) hydrogel film co-crosslinked by electron beam irradiation as an anti-adhesion barrier

International Nuclear Information System (INIS)

Haryanto,; Singh, Deepti; Han, Sung Soo; Son, Jun Hyuk; Kim, Seong Cheol

2015-01-01

The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC–5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33 ± 6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03 ± 0.01%) and the highest tissue adherence (75.67 ± 1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®. - Highlights: • The crosslinked PEGDC/PEO hydrogel was developed by e-beam irradiation. • 10% PEGDC hydrogel film showed the highest elongation at break and tissue adhesion. • The COOH group enhanced the tissue adherence of hydrogel films on the intestine. • 10% PEGDC hydrogel film demonstrated a good anti-adhesive effect in animal study. • All of the hydrogel films with 10% PEGDC degraded in vivo within three weeks

Chemical modification of high molecular weight polyethylene through gamma radiation for biomaterials applications

International Nuclear Information System (INIS)

Raposo, Matheus P.; Rocha, Marisa C.G.

2015-01-01

Ultra high molecular weight polyethylene has been used in the medical field due to its high mechanical properties compared to the other polymers. Its main application is in the development of orthopedic implants, which requires high resistance to abrasion. One of the most used methods is the introduction of crosslinks in the polymer through gamma irradiation. In order to prevent oxidation reactions, studies have been developed using tacoferol (vitamin E) as an antioxidant for the material. The ascorbic acid (vitamin C), however, has been appointed as a viable alternative for vitamin E. In this work, a high molecular weight polyethylene grade (HMWPE) and polyethylene samples formulated with vitamin C were submitted to gamma radiation. Thermodynamic-mechanical methods and gel content determinations were used to characterize the samples obtained. The sample containing 1% of vitamin C and irradiated with 50 KGy of gamma radiation presented the highest content of crosslinks. (author)

The improvement of polyethylene prostheses through radiation crosslinking

International Nuclear Information System (INIS)

Du Plessis, T.A.; Grobbelaar, C.J.; Marais, F.

1977-01-01

During the past decade, remarkable progress has been made in the utilization of high-density polyethylene (HDPE) as a material for the manufacture of prostheses used in orthopaedic operations. This polymer contributes largely to the success of total hip replacement. In the case of total knee replacement it was considered imperative that a more hard-wearing polymer should be developed if at all possible, because not only are the cold-flow characteristics of ordinary high-density polyethylene at high pressures a limiting factor, but particle formation from friction can furthermore lead to physiological side-effects which adversely affect the efficacy of joints made from this material, especially so in the case of knee-joints. Bearing in mind the excellent improvements to be obtained through the radiation crosslinking of polyethylene film, the radiation crosslinking of high-density polyethylene prostheses seemed to be a logical avenue to investigate. Experimental details are presented. Gamma radiation was used. Impact strength and tensile strength measurements were made on specimens irradiated over a dose range of 0 to 80 Mrad. The results are discussed. (U.K.)

Biodegradation of low-density polyethylene (LDPE by mixed culture of Lysinibacillus xylanilyticus and Aspergillus niger in soil.

Directory of Open Access Journals (Sweden)

Atefeh Esmaeili

Full Text Available In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR, x-ray diffraction (XRD and scanning electron microscopy (SEM were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source.

Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil

Science.gov (United States)

Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

2013-01-01

In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source. PMID:24086254

Manufacture of polyethylene foam by electron beam cross-linking

International Nuclear Information System (INIS)

Tamai, Isamu

1976-01-01

The manufacturing process of polyethylene foam, comparison between electron beam cross-linking process and chemical cross-linking process, the electron beam irradiation technique for continuous sheets, the characteristics and uses of polyethylene foam are reviewed. The pore diameter can be controlled by selecting the dose rate, because there is strong relationship between the pore diameter and the dose rate. As the dose if higher, the foam becomes finer. The electron accelerators having large capacity show the lowest cost as the radiation source, and are applicable industrially. If the production capacity exceeds about 200 tons per month, the costs of electron beam irradiation process may be more advantageous than that of chemical process according to the circumstances. It is difficult to obtain the uniform distribution of absorption dose in the direction of thickness. General characteristics of cross-linked polyethylene foam are listed. The special feature of electron beam process is that the degree of cross-linking can be controlled arbitrarily before foaming. The products obtained by the electron beam cross-linking process have finer foams and smoother surfaces than those obtained by the chemical process, because the separation of the decomposition of foaming agents from that of cross-linking agents in the chemical cross-linking is difficult. (Iwakiri, K.)

Effects of gamma irradiation on antioxidants and ultraviolet stabilizers

International Nuclear Information System (INIS)

Kawamura, Yoko; Miura, Makiko; Miura, Yukiko; Yamada, Takashi

1998-01-01

The effects of gamma irradiation on 18 kinds of antioxidants and 10 kinds of ultraviolet stabilizers, intact or in a polyethylene sheet, were studied. After irradiating at a 30kGy dose, the content of additives themselves did not change and new degradation products were not found. While most antioxidants in polyethylene had a decreased content after irradiation, most ultraviolet stabilizers did not change. During the migration tests with aqueous food simulants, additives were not released from either irradiated or unirradiated sheets. For the migration tests with n-heptane, however, all additives were released from the unirradiated sheet, while most of the antioxidants were not released or released only slightly. (author)

Induced effects of gamma-rays and fast neutrons on the D.C. electric resistivity of polyethylene for high level dosimetry

International Nuclear Information System (INIS)

Youssef, S.K.; Mashad, A.M.; Osiris, W.C.; Adawi, M.A.

1988-01-01

The effects of gamma- and neutron-irradiations on the D.C. electric resistivity of polyethylene were investigated. The results showed that, the D.C. electric resistivity of polyethylene decreased as the samples irradiation by gamma doses as well as fast neutron fluences over the ranges 10 2 -6x10 6 Gy, and 10 8 -10 11 n/cm 2 , respectively. Moreover, electric resistivity of the polyethylene samples indicated more sensitivity change when irradiated by fast neutrons in comparison with equivalent doses of gamma-radiation. Semi-empirical formulae were deduced for the calculation of gamma-dose and/or neutron fluence from the changes in the electric resistivity of the detector. Storage of the irradiated specimens at room decay temperature showed a continuous increase in the relative fade of electric resistivity by recovery with time. The retained electric resistivity by recovery showed values of about 47% and 33% for post specimens irradiated by 6x10 6 Gy and 1x10 11 n/cm 2 , respectively, after 80 hours

Physico-mechanical Properties of Electron Beam Irradiated Particle boards Based on Wood flour/ Polyethylene/Cement Kiln Dust Impregnated with Unsaturated Polyester

International Nuclear Information System (INIS)

Abdel-Rahman, H.A.; Khattab, M.M.; Ismail, M.R.

2010-01-01

Particle boards were fabricated by mixing wood flour (WF), low density polyethylene (LDPE) and cement kiln dust (CKD) under hot pressure; and then impregnated in unsaturated polyester resin. These impregnated particle boards were subjected to various doses of electron beam irradiation up to 50 kGy. The physico-mechanical properties were characterized in terms of flexural strength, impact strength, water absorption, thickness swelling, and the thermal stability. The results showed that the partial replacement of wood flour with cement kiln dust up to 20% by weight improved the values of flexural strength, and impact strength. However, the water absorption percentage and thickness swelling values decreased with increasing the CKD ratio up to 40%. Furthermore, the treatment with electron beam irradiation doses improved the physico-mechanical properties of the impregnated particle boards up to 50 kGy. The improved results were confirmed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA)

Polypropylene-polyethylene blends modified by gamma radiation

International Nuclear Information System (INIS)

Terence, Mauro C.; Ruiz, Francisco C.

2009-01-01

One way to obtain a better mechanical property of polypropylene and polyethylene is to increasing the number of polymer chains cross-linked by gamma radiation. After irradiation a network is formed as a result of various chemical reactions and the radicals formed are concentrated in the amorphous phase. With the objective to improve the mechanical properties of PP, blends with PE were prepared and irradiated in doses up to 500 kGy, in atmospheric ambient. The molecular characterization of the blends was made by infrared spectroscopy and the data showed an increase in rigidity and a unique behaviour in Izod impact resistance. (author)

The effect of gamma irradiation and shelf aging in air on the oxidation of ultra-high molecular weight polyethylene

International Nuclear Information System (INIS)

Al-Ma'adeed, M.A.; Al-Qaradawi, I.Y.; Madi, N.; Al-Thani, N.J.

2006-01-01

This study has investigated the effect of shelf aging, for up to one year in air, on the properties of gamma-irradiated ultra-high molecular weight polyethylene (UHMWPE). A variety of techniques were used to characterize the properties of treated samples. Differential scanning calorimetery (DSC) was used to characterize the morphology. The extent of cross-linking in a polymer network was detected by swelling measurements. The durometer hardness test was used to measure the relative hardness of this material, and changes in density were also measured. Results from all these measurements were combined to explain the changes in the microstructure of the aged, irradiated UHMWPE. This study shows that crystallinity is increased with radiation dose and with aging due to chain scission, which leads to a reduction in the molecular weight of the material. This allows the chains to rearrange to form crystalline regions. Positron annihilation lifetime spectroscopy confirms these conclusions. Fractional free volumes have been deduced from lifetime parameters, which correlate with the data obtained by the other techniques

Enhancement of photocatalytic degradation of polyethylene plastic with CuPc modified TiO2 photocatalyst under solar light irradiation

International Nuclear Information System (INIS)

Zhao Xu; Li Zongwei; Chen Yi; Shi Liyi; Zhu Yongfa

2008-01-01

Solid-phase photocatalytic degradation of polyethylene (PE) plastic, one of the most common commercial plastic, over copper phthalocyanine (CuPc) modified TiO 2 (TiO 2 /CuPc) photocatalyst was investigated in the ambient air under solar light irradiation. Higher PE weight loss rate, greater texture change; more amount of generated CO 2 , which is the main product of the photocatalytic degradation of the composite PEC plastic can be achieved in the system of PE-(TiO 2 /CuPc) in comparison with PE-TiO 2 system. The CuPc promoted charge separation of TiO 2 and enhanced the photocatalytic degradation of PE based on the analysis of surface photovoltage spectroscopy (SPS). During the photodegradation of PE plastic, the reactive oxygen species generated on TiO 2 or TiO 2 /CuPc particle surfaces play important roles. The present study demonstrates that the combination of polymer plastic with TiO 2 /CuPc composite photocatalyst in the form of thin film is a practical and useful way to photodegrade plastic contaminants under solar light irradiation

Diffusion and solubility of oxygen in γ-ray irradiated polymer insulation materials

International Nuclear Information System (INIS)

Seguchi, Tadao; Yamamoto, Yasuaki.

1986-03-01

The effects of 60 Co γ-rays irradiation on diffusion and solubility of oxygen in polymer materials for electric cable insulation materials were investigated. The polymers were polyethylene, ethylene-propylene rubber, chlorinated polyethylene, chlorosulphonated polyethylene, and chloroprene rubber. They were pure grade and several types of formulation grade. The sheets of these polymers were irradiated up to 5 - 200 Mrad under vacuum or in oxygen under pressure of 3 - 15 atm at room temperature or at 70 deg C. By a method of gas desorption, the diffusion coefficient (D) and solubility coefficient (S) of oxygen or argon in polymer materials were determined at various temperatures of 10 - 80 deg C. The D and S decreased with increase of dose, and the decrease by irradiation with oxidation was more remarkable than that by irradiation without oxidation. However, the decreases of D and S by irradiation were reduced by the formulation of polymers. The additives in formulated polymers would reduce the reactions of crosslinking or oxidation by γ-ray irradiation. The activation energy of D was scarcely changed by irradiations with and without oxidation. (author)

Chemical and physical change of packaging materials for food by γ-ray irradiation

International Nuclear Information System (INIS)

Kawamura, Yoko; Takeda, Yuiko; Yamada, Takashi

1998-01-01

Packaging materials for food made of polyethylene, polypropylene and polystyrene were irradiated with 60 Co γ-ray. Exposure was 10, 30 and 50 kGy at 5 kGy/h exposure rate. With irradiating, all packaging materials of polyethylene and polypropylene produced volatile substances, for example, aldehydes, ketones and alcohols, especially, large amount of acetic acid and acetone. These volatile compounds were not observed in the sample unirradiated and increased with increasing exposure. Accordingly, it is concluded that they were decomposition products depend on irradiation. Polypropylene products were much more easily decomposed than polyethylene one because much more kinds and amount of volatile products were formed. However, on polystyrene products, content of styrene and ethylbenzene, monomer of raw materials, were reduced by irradiation and small amount of volatile substances were formed. These results proved its resistance to irradiation. (S.Y.)

Chemical and Biological Studies on Cumin Fruits Irradiated by GAMMA Rays for Conservation

International Nuclear Information System (INIS)

HASSANEIN, R.A.M.

2011-01-01

The aim of this study was to investigate the effect of different doses of gamma irradiation (0, 5, 10 and 15 KGy) and different storage periods (0, 3 and 6 months) in different package materials (cotton or polyethylene bags) on essential oil quality and chemical composition of cumin (Cuminum cyminum) fruits. On the other hand antimicrobial activity of treated cumin fruits essential oil and its extracts at 0, 5000, 10000, 20000 and 40000 ppm were investigated. Results showed that the highest essential oil % was obtained from fruits stored for 3 months in cotton bag without gamma irradiation. Concerning the effect of essential oil as antimicrobial agent, the highest antibacterial activity was obtained by essential oil isolated from irradiated polyethylene packed fruits at 5 KGy then stored for 3 months (Staphylococcus aureus) or irradiated polyethylene packed ones at 15 KGy without storage (Salmonella typhimurium). On the other hand, the highest antifungal activity against Aspergillus niger and Penicillium digitatum was obtained by essential oil isolated from unirradiated packed in polyethylene fruits then stored for 6 months. Non-stored packed in cotton bag fruits irradiated with gamma rays at 10 KGy produced essential oil with highest antiyeastal activity. Cumin fruits extract at 40000 ppm when combined with different treatments presented the highest antimicrobial activity (represents as inhibition zone) against all studied microbes except with P. digitatum. Cumin extract at 40000 ppm when extracted from irradiated packed fruits in polyethylene bags with gamma rays at 5 KGy without storage or with 6 months storage or irradiated at 15 KGy of packed fruits in cotton bag with storage for 3 months presented the highest significant inhibition zones against S. aureus. The same concentration of extracted cumin from uni radiated packed in cotton bag fruits and storage for 6 months presented the highest inhibition zone of S. typhimurium. Also, with the same concentration

Effects of trace fillers on the radiation-induced crosslinking of polyethylene

International Nuclear Information System (INIS)

Chappas, W.J.; Silverman, J.

1979-01-01

Silica-filled samples of low-density polyethylene were subjected to γ and electron irradiation. The insoluble fraction determined by Soxhlet extraction was found to be independent of filler concentrations up to 0.5% by volume. The results show no evidence to support the previously reported work by Gordiyenko et al. of a sharp increase in the gel fraction of irradiated samples with filler concentrations of 0.2%. Substantial changes in the conditions of irradiation and of sample preparation and treatment do not affect gel yields strongly

Thermal, mechanical and permeation properties of gamma-irradiated multilayer food packaging films containing a buried layer of recycled low-density polyethylene

International Nuclear Information System (INIS)

Chytiri, Stavroula; Goulas, Antonios E.; Riganakos, Kyriakos A.; Kontominas, Michael G.

2006-01-01

The effect of gamma radiation (doses 5-60kGy) on the thermal, mechanical and permeation properties, as well as on IR-spectra of experimental five-layer food packaging films were studied. Films contained a middle buried layer of recycled low-density polyethylene (LDPE) comprising 25-50% by weight of the multilayer structure. Representative films containing 100% virgin LDPE as the buried layer were taken as controls. Results showed that the percentage of recycled LDPE in the multilayer structure did not significantly (p<0.05) affect the melting temperature, tensile strength, percent elongation at break, Young's modulus, oxygen, carbon dioxide and water vapour transmission rate values and the IR-spectra of the non-irradiated and irradiated multilayer films. Irradiation (mainly the higher dose of 60kGy) induced certain small, but statistically significant (p<0.05) differences in the mechanical properties of multilayer films (with or without recycled LDPE layer) while no significant differences were observed in the thermal properties and in the gas and water vapour permeability of multilayer films. The above findings are discussed in relation to the good quality of the pre-consumer scrap used in the present study

Facile preparation of super-hydrophilic poly(ethylene terephthalate) fabric using dilute sulfuric acid under microwave irradiation

Energy Technology Data Exchange (ETDEWEB)

Xu, Fang [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Guangxian, E-mail: zgx656472@sina.com.cn [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Fengxiu [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang, Yuansong [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China)

2015-09-15

Highlights: • A durable super-hydrophilic PET fabric was prepared using dilute H{sub 2}SO{sub 4} under microwave irradiation. • Dilute sulfuric acid was gradually concentrated enough to sulfonate PET fabric. • Microwave irradiation made PET fabric modification highly efficient. • The mechanical properties of modified PET fibers were kept well. • The method was novel, rapid, and eco-friendly. - Abstract: The hydrophilicity of a poly(ethylene terephthalate) (PET) fabric was greatly modified by using dilute sulfuric acid, which gradually became concentrated enough to sulfonate the fabric when microwave irradiation (MW) was applied. The modified PET fabric was super-hydrophilic. Modifying the fabric caused the water contact angle to decrease from 132.46 (for the unmodified fabric) to 0°, the water absorption rate to increase from 36.45 to 119.78%, and the capillary rise height to increase from 0.4 to 14.4 cm. The hydrophilicity of the modified PET fabric was not affected by washing it many times. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that there were sulfonic acid groups on the modified fibers. Almost no difference between the surfaces of the unmodified and modified PET fibers was found using scanning electron microscopy. Analysis by differential scanning calorimetry showed that the unmodified and modified fabrics had similar thermostabilities. X-ray diffraction analysis of the crystalline structures of the unmodified and modified fibers showed that they were almost the same. The strength, elasticity, and rigidity of the unmodified fabric were retained by the modified fabric. The modified fabric had better dyeing properties than the unmodified fabric.

Electroless plating Cu-Co-P polyalloy on UV/ozonolysis irradiated polyethylene terephthalate film and its corrosion resistance

Energy Technology Data Exchange (ETDEWEB)

Hou, Lei; Bi, Siyi; Zhao, Hang; Xu, Yumeng; Mu, Yuhang; Lu, Yinxiang, E-mail: yxlu@fudan.edu.cn

2017-05-01

Highlights: • Electroless plating Cu-Co-P polyalloy was firstly fabricated onto polyethylene terephthalate (PET) substrate. • An etchant-free and amine-free UV/ozonolysis irradiation method UV/ozonolysis was effective for the transition from hydrophilic to hydrophobic of PET sheet. • A time-saving and cost-effective orthogonal experiment (L{sub 9}(3){sup 4}) was utilized to optimize the plating conditions. • The optimized copper polyalloy possessed high corrosion resistance in three aggressive mediums including NaCl, NaOH and HCl, respectively. • The Cu-Co-P coated PET composite showed excellent electromagnetic interference shielding effectiveness (EMI SE > 99.999% at frequency ranging from 30 MHz to 1000 MHz). - Abstract: High corrosion resistant Cu-Co-P coatings were firstly prepared on polyethylene terephthalate (PET) substrate by electroless plating in combination with UV/ozonolysis irradiation under optimized cobalt sulfate heptahydrate concentration, pH value, plating temperature and time. The copper polyalloy/PET composite can be obtained in three steps, namely: (i) the generation of oxygen-containing functionalities (carboxylic groups) onto PET surface through UV irradiation combined with ozone, (ii) Cu seeding catalysts were obtained after being immersed into cupric citrate and NaBH{sub 4} solutions subsequently, and (iii) Cu-Co-P polyalloy metallization using electroless plating bath. Attenuated total reflection fourier transformation infrared spectrometer (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), water contact angle measurement and energy dispersive X-ray analysis (EDAX) were utilized to track the surface changes during the whole process. The electroless plating conditions were optimized by an orthogonal experiment (L{sub 9}(3){sup 4}) for Cu-Co-P coating as follows: CoSO{sub 4}·7H{sub 2}O addition of 0.08 M, pH value, plating temperature and time were set on 10.0, 35 °C and 25 min, respectively. Under the optimal conditions, copper

The dose distribution determination in two kinds of polyethylene materials irradiated by electron beams-an experimental method for optimizing technology of radiation processing

International Nuclear Information System (INIS)

Zhang Daming

2000-01-01

The dose distribution in two kinds of polyethylene materials were determined by use of electron beam from 1.0-3.0 MeV electron accelerator. The effects of four different metal base-plate such as Al, Fe, Cu and Pb for dose depth distribution in materials were compared. And the boundary effects of absorbed dose were also observed. The expand uncertainty of absorbed dose measurement was 7.8%. This work is a useful experimental method for optimizing technology of radiation processing and realizing quality control of irradiation products

Analysis of Hydroperoxides in Solid Polyethylene by MAS (13)C NMR and EPR

International Nuclear Information System (INIS)

ASSINK, ROGER A.; CELINA, MATHIAS C.; DUNBAR, TIMOTHY D.; ALAM, TODD M.; CLOUGH, ROGER LEE; GILLEN, KENNETH T.

1999-01-01

13 C-enriched polyethylene was subjected to γ-irradiation in the presence of air at 25 and 80 C for total doses ranging from 71 to 355 kGy. Significant quantities of hydroperoxides were detected in the 25 C irradiated sample by 13 C magic angle spinning NMR spectroscopy. This method of detection was performed on the solid polymer and required no chemical derivatization or addition of solvent. The chemical stability and subsequent products of the hydroperoxide species were studied by annealing the irradiated samples in air at temperatures ranging from 22 to 110 C. A time-temperature superposition analysis provided an activation energy of 108 kJ/mol for the hydroperoxide decomposition process. The primary products of hydroperoxide decomposition were ketones and secondary alcohols with lesser amounts of acids and esters. EPR measurements suggest that the reactive hydroperoxide species reside in the amorphous phase of polyethylene, consistent with degradation occurring in the amorphous phase

南中国斑节对虾养殖中控制白斑综合症病的理论和策略%Theory and Strategies for Controlling White Spot Syndrome (WSS) of Cultured Penaeus monodon in South China

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

@@ White spot syndrome virus (WSSV) is the causative agent of white spot syndrome (WSS) of cultured penaeid shrimps. WSS breaks out and prevails in cultured penaeid shrimps in many countries and regions of the world, especially in southeast Asia. WSSV is the virus most severe damaging to the cultured penaeid shrimps in the world. At the present time, the control of the outbreaks of WSSV will recover and develop the penaeid shrimp cultures in China and even in the world.

Effect of Radiation on Physical and Mechanical Properties of Polyblend polyethylene (LDPE)-Akrilonitril Butadiene Styrene(ADS)

International Nuclear Information System (INIS)

Infrawan, M.H.; Mashuri; Sudirman

2001-01-01

Poly blend material is blended material that made of two or more polymer material with or without chemical reaction. Polyethylene (LDPE)- ABS poly blend material was made of two materials, ABS resin and Low Density Polyethylene (LDPE). This research is conducted to synthesize LDPE and ABS poly blend material before and after irradiation by γ ray and to investigate the effect of γ-ray irradiation doses on mechanical, and physical properties. This effect will enhanced mechanical properties of poly blend LDPE and ABS material that was caused by crosslinking. The gel fraction showed that the crosslinking occurred. The other effect of γ-ray irradiation are increased tensile strength and melting point, but the elongation at break, and yield strength decreased. The best composition to get the best properties is 5 % LDPE : 95 % ABS

Gains or Losses of Ultratrace Elements in Polyethylene Containers

DEFF Research Database (Denmark)

Heydorn, Kaj; Damsgaard, Else

1982-01-01

The extent of elimination of losses and reduction of blank values in ultratrace elemental analysis can only be ascertained by comprehensive investigations for each element separately. Different, and partially conflicting precautions are found to be needed in the determination of manganese, copper......, selenium, and mercury by neutron-activation analysis when polyethylene irradiation containers are used....

Studies on extension of shelf-life of rawa by gamma irradiation

International Nuclear Information System (INIS)

Sudha Rao, V.; Srirangarajan, A.N.; Kamat, A.S.; Adhikari, H.R.; Nair, P.M.

1994-01-01

Semolina, a wheat product, popularly termed as rawa, was packed in 500g pouches prepared individually from high density polyethylene (HDP), biaxially oriented polypropylene : low density polyethylene laminate (BOPP/LDP), polyester : low density polyethylene laminate (PET/LDP) and irradiated using a Cobalt-60 source at dose of 0.15 to 0.50 kGy. At the end of six months' storage at room temperature, the unirradiated rawa developed infestation, whereas the irradiated samples were completely free of any infestation, thereby indicating a complete destruction of all stages of the insects due to irradiation. There was no significant difference in the moisture content and the total bacterial as well as mould counts of the irradiated and unirradiated rawa. Gamma irradiation significantly decreased the gelatinization viscosity of rawa. In sensory evaluation tests, irradiated rawa scored the same on a 9-point Hedonic scale, thereby showing that overall acceptability of the rawa was not altered due to irradiation upto 0.25 kGy. Amongst the packaging materials used, BOPP/LDP was found to be better, because of its comparatively higher resistance to penetration by insects. Gamma irradiation at 0.25 kGy could thus be recommended for effectively extending the shelf-life of rawa, prepacked in pouches made from BOPP/LDP laminate, for six months. (author). 26 refs., 1 fig., 2 tabs

Heavy ion irradiation effects of polymer film on absorption of light

Energy Technology Data Exchange (ETDEWEB)

Kasai, Noboru; Seguchi, Tadao [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Arakawa, Tetsuhito

1997-03-01

Ion irradiation effects on the absorption of light for three types of polymer films; polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN), and polyether-ether-ketone (PEEK) were investigated by irradiation of heavy ions with Ni{sup 4+}(15MeV), O{sup 6+}(160MeV), and Ar{sup 8+}(175MeV), and compared with electron beams(EB) irradiation. The change of absorption at 400nm by a photometer was almost proportional to total dose for ions and EB. The absorption per absorbed dose was much high in Ni{sup 4+}, but rather small in O{sup 6+} and Ar{sup 8+} irradiation, and the absorption by EB irradiation was accelerated by the temperature of polymer film during irradiation. The beam heating of materials during ion irradiation was assumed, especially for Ni ion irradiation. The heavy ion irradiation effect of polymers was thought to be much affected by the ion beam heating than the linear energy transfer(LET) of radiation source. (author)

Determination of the boron content in polyethylene samples using the reactor Orphée

CERN Document Server

Gunsing, F; Aberle, O

2017-01-01

The boron content of two unknown types of polyethylene has been determined relative to a known reference type. Samples of polyethylene, including a known boron-less one, were irradiated with thermal neutrons at the reactor Orphée at Saclay in France. Prompt gamma rays were measured with a CeBr$_3$ detector and the intensity of the 478~keV line from $^{10}${B}(n,$\\alpha_1\\gamma$)$^{7}{Li*} was extracted.

Quantitative analysis of the gas evolved from high polymers in γ-irradiation

International Nuclear Information System (INIS)

Arakawa, Kazuo; Hayakawa, Naohiro; Kuriyama, Isamu

1977-09-01

Polymers are used as insulator of cables in nuclear-reactor radiation field. To estimate the evolution of gases when irradiated, total gas yield and composition were measured for variety of polymers. Samples were irradiated at room temperature in vacuo with 60 Co-γ rays. For ethylene propylene rubber (EPR), irradiation in high-temperature steam was also made. Composition of the gas was determined with a mass spectrometer. G-value of the total gaseous product was 3.2 to 3.4 for low-density polyethylene (LDPE) and 2.5 to 2.7 for high-density polyethylene (HDPE). In both polyethylene, hydrogen gas predominated. When an anti-radiation oil was added to LDPE, gas evolution was reduced drastically. For chloro-sulfonated PE (Hypalon), SO 2 gas was one of the major products even when the polymer contained only about 1% of sulfonyl groups. G-value of the total gas for EPR irradiated in high-temperature steam was 3.1, regardless of the temperature. (auth.)

ESR Study of PE, HDPE and UHMWPE Irradiated with Ion Beams and Neutrons

International Nuclear Information System (INIS)

Reyes-Romero, J.

2006-01-01

We report the Electron Spin Resonance (RES) studies on the effects produced by bombarding with accelerated Sulfur ions, Protons and Neutrons on the Polyethylene, PE, (Hostalen and Romanian), ultra-high molecular weight polyethylene, UHMWPE, ( GUR 1050, medical grade Lennite), and high density polyethylene, HDPE, (HDPE-7000F, Polinter de Venezuela, PDVSA). The resonance spectra have been recorded using a Varian E-line-X ESR spectrometer at 100 KHz modulation frequency. In thin films of Polyethylene (Hostalen and UHMWPE) have been irradiated with Sulfur ions, S, accelerated at about 7 MeV/nucleons, and Protons at about 5 MeV/nucleons (IFIN, Romania). Samples of Polyethylene ( HDPE 7000-F) were irradiate with neutrons from a Pu-Be source (flux of 1.19 x 10 6 n/s. cm 2 , 5.65 MeV, IVIC, Venezuela) from 0 to 8 hours in the presence of air and at room temperature (RT). The ESR measurements were performed after a storage time of about 7 months, in air at room temperature. The nature of the free radicals induced by irradiation as well as the dependence of resonance line, resonance line shape and radicals concentration has been studied

Mechanism of trans-vinylene groups formation in the radiolysis of polyethylene and n-alkanes

International Nuclear Information System (INIS)

Borzov, S.M.; Sukhov, F.F.; Slovokhotova, N.A.

1984-01-01

Infrared spectra of polyethylene and some n-alkanes were studied after their irradiation at 20 K with 1-MeV electrons and subsequent heating to 160 K. The mechanism of trans-vinylene groups formation is suggested, which takes into account the decay of excited states of molecules in primary processes and the intra-chain recombination of free radicals in post-irradiation reactions. (author)

The effect of different stabilizers on the thermostability of electron beam crosslinked polyethylene in hot water

International Nuclear Information System (INIS)

Hassanpour, S.; Khoylou, F.

2003-01-01

Plastic pipes owing to their flexibility, great lengths, easier handling and absence of corrosion have been used for hot-water installations. Crosslinked high-density polyethylene is one of the best materials, being used for this purpose. The useful lifetime of unstabilized polyethylene is predicted to vary from a few months in hot water (30-40 deg. C) to almost two years in cool water (0-10 deg. C). Polyethylene was mixed with different types of stabilizers, in order to increase its durability. The samples were irradiated at 100-150 kGy. The amount of gel fraction and the changes in mechanical properties were measured. Irradiated samples were immersed in hot water for 1000 h. The thermostability of the specimens and the existence of antioxidants were measured by the induction time technique using differential scanning calorimetry at different time intervals. Furthermore, the changes in chemical structure and mechanical properties of the samples during their immersion in hot water were determined

Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

Energy Technology Data Exchange (ETDEWEB)

Sherazi, Tauqir A. [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Guiver, Michael D.; Kingston, David; Xue, Xinzhong [Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Ahmad, Shujaat [PIEAS/PINSTECH, P O Nilore, Islamabad 45650 (Pakistan); Kashmiri, M. Akram [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Board of Intermediate and Secondary Education, Lahore 54000 (Pakistan)

2010-01-01

Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a {sup 60}Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by X-ray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion {sup registered} 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acid-type membranes for DMFC. (author)

Studies on the memory effect in polyethylene

International Nuclear Information System (INIS)

Lopez, M.A.; Burillo, G.; Charlesby, A.

1994-01-01

Polyethylene films of LDPE, a commercial product of PEMEX Mexico, with three different thicknesses were stretched from 1 cm to various lengths, and irradiated in air and in vacuum, at doses from 0 to 730 kGy. The effect of stretching on the ''memory effect'', % of gel formed, crystallinity, radio-chemical yield of crosslinking G c and scission G d was determined. Maximum shrinking effect is obtained at temperatures above the crystalline melting point, and is almost the same at any irradiation dose, from 0 to 525 kGy; in the case of doses from 713 kGy up, the recovery decreases slightly due to higher density of crosslinking. The increase of draw ratio from 5 to 6.5 has no significant effect on recovery. Preirradiation of 40 kGy in air before stretching has no significant effect on recovery but minimizes possible creep during the stretching and irradiation process. (author)

A comparison of the efficacy of various antioxidants on the oxidative stability of irradiated polyethylene.

Science.gov (United States)

Hope, Natalie; Bellare, Anuj

2015-03-01

Ultrahigh-molecular-weight polyethylene (UHMWPE) is subjected to radiation crosslinking to form highly crosslinked polyethylene (HXLPE), which has improved wear resistance. First-generation HXLPE was subjected to thermal treatment to reduce or quench free radicals that can induce long-term oxidative degeneration. Most recently, antioxidants have been added to HXLPE to induce oxidative resistance rather than by thermal treatment. However, antioxidants can interfere with the efficiency of radiation crosslinking. We sought to identify (1) which antioxidant from among those tested (vitamin E, β-carotene, butylated hydroxytoluene, or pentaerythritol tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]) causes the least reduction of crosslinking; (2) which promotes the greatest oxidative stability; and (3) which had the lowest ratio of oxidation index to crosslink density. Medical-grade polyethylene (PE) resin was blended with 0.1 weight % of the following stabilizers: alpha tocopherol (vitamin E), β-carotene, butylated hydroxytoluene (BHT), and pentaerythritol tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (a hindered phenol antioxidant [HPAO]). These blends were compression-molded into sheets and subjected to electron beam irradiation to a dose of 100 kGy. Equilibrium swelling experiments were conducted to calculate crosslink density. Each PE was subjected to accelerated aging for a period of 2 weeks and Fourier transform infrared spectroscopy was used to measure the maximum oxidation. Statistical analysis was conducted using analysis of variance with Fisher's protected least significant difference in which a p value of tested (1.49, ES = 1.94; 95% CI, 1.32-1.66) followed by HPAO-PE (1.70, ES = 1.52; 95% CI, 1.61-1.80), vitamin E-PE (2.21, ES = 0.52; 95% CI, 2.05-2.38), and β-carotene-PE (2.69, ES = -0.43; 95% CI, 2.46-2.93) compared with control PE (2.47, 95% CI, 2.07-2.88) with β-carotene (p = 0.208) and vitamin E (p = 0

Volatile and non-volatile radiolysis products in irradiated multilayer coextruded food-packaging films containing a buried layer of recycled low-density polyethylene.

Science.gov (United States)

Chytiri, S; Goulas, A E; Badeka, A; Riganakos, K A; Kontominas, M G

2005-12-01

The effects of gamma-irradiation (5-60 kGy) on radiolysis products and sensory changes of experimental five-layer food-packaging films were determined. Films contained a middle buried layer of recycled low-density polyethylene (LDPE) comprising 25-50% by weight (bw) of the multilayer structure. Respective films containing 100% virgin LDPE as the buried layer were used as controls. Under realistic polymer/food simulant contact conditions during irradiation, a large number of primary and secondary radiolysis products (hydrocarbons, aldehydes, ketones, alcohols, carboxylic acids) were produced. These compounds were detected in the food simulant after contact with all films tested, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food preservation). The type and concentration of radiolysis products increased progressively with increasing dose. Generally, there were no significant differences in radiolysis products between samples containing a buried layer of recycled LDPE and those containing virgin LDPE (all absorbed doses), indicating the good barrier properties of external virgin polymer layers. Volatile and non-volatile compounds produced during irradiation affected the sensory properties of potable water after contact with packaging films. Taste transfer to water was observed mainly at higher doses and was more noticeable for multilayer structures containing recycled LDPE, even though differences were slight.

Properties of a composite of polyethylene and cellulose fibers of sugarcane bagasse

International Nuclear Information System (INIS)

Romero, G.R.; Gonzalez, Maria E.

2003-01-01

One way of revalorizing agricultural wastes is to combine them with synthetic polymers to obtain adequate materials for certain purposes. In this paper, a trial was made to incorporate the maximum possible amount of lignocellulose fibers from sugarcane bagasse into a polyethylene matrix. The mixture was performed by means of a laboratory extruder with corotating twin screw. During the extrusion of polyethylene, the fiber was gradually added through the feeding hopper. A composition of about 50 % (w/w) of PE - fiber was obtained. Higher fiber content resulted in a lack of cohesion of the extruded material. The extruded bars were molded into 3-mm sheets by compression molding at 140 C degrees and 20 Ton. Irradiation of the molded sheets was performed with the aim of improving the material properties. Water absorption was measured according to the procedures of ASTM D 570-95, at 25 C degrees, 60 C degrees and 100 C degrees, in comparison with non-irradiated material. Less than 4 % (w/w) water absorption was measured at the higher temperatures, with no significant differences between irradiated and control samples. At 25 C degrees, after 168-h immersion, water absorption of irradiated samples was 5.3 % while control ones absorbed 6.5%. No dimensional changes were noticed after drying of the tested probes. According to these results, the material presented very good resistance to the action of water. However, no important effect was obtained by irradiation. This suggests that either the irradiation dose or the irradiation conditions were not adequate to induce an appreciable degree of crosslinking. This aspect will be studied by means of irradiation with increasing doses and measuring the crosslinking degree. Mechanical properties of obtained materials will also be studied. (author)

Poly(acrylic acid)/polyethylene glycol hygrogel prepared by using gamma-ray irradiation for mucosa adhesion

Energy Technology Data Exchange (ETDEWEB)

Nho, Young-Chang; Park, Jong-Seok; Shin, Jung-Woong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Gwon, Hui-Jeong [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Khil, Myung-Seob [Chonbuk National University, Jeonju (Korea, Republic of); Lee, Deok-Won [Maxillofacial Surgery Dental Hospital, Seoul (Korea, Republic of); Ahn, Sung-Jun [JADAM Co., LTD., Seogwipo (Korea, Republic of)

2015-01-15

A buccal delivery system provides a much milder environment for drug delivery compared to an oral delivery which presents a hostile environment for drugs, especially proteins and polypeptides, owing to acid hydrolysis. Local delivery in an oral cavity has particular applications in the treatment of toothaches, periodontal disease, and bacterial infections. Poly(acrylic acid) (PAA)-based hydrogels prepared using a chemical initiator have been attempted for a mucoadhesive system owing to their flexibility and excellent bioadhesion. In this experiment, PAA and polyethylene glycol (PEG) were selected to prepare using a radiation process a bioadhesive hydrogel for adhesion to mucosal surfaces. PAA and PEG were dissolved in purified water to prepare a homogeneous PAA/PEG solution, and the solution was then irradiated using an electron beam at dose up to 70 kGy to make the hydrogels. Their physical properties, such as gel percent, swelling percent, and adhesive strength to mucosal surfaces, were investigated. In this experiment, various amounts of PEG were incorporated into the PAA to enhance the mucoadhesive property of the hydrogels. The effect of the molecular weight of PEG on the mucoadhesion was also examined.

Ionising radiation dosimetry by measuring thermally excited currents (TEC) in irradiated highpolymers

International Nuclear Information System (INIS)

Shtol'ts, V.; Petermann, V.; Nigot, V.

1976-01-01

The first results are presented in measuring thermally excited currents (TEC) in 60 Co - gamma irradiated polyethylene and teflon. The design of measuring instruments is described. The maximum background currents in nonirradiated samples reached 10 -13 A. The TEC curves are presented which have obtained under irradiation up to 0.1-1000 rad followed by heating in the temperature range from 20 to 250 deg C. The curves exhibited maxima at about 90 deg C for polyethylene and about 200 deg C for teflon. The TEC dose range has been determined to be 0.1-1000 rad and 5-1000 rad for polyethylene and teflon, respectively. The fading at room temperature after 100 hrs has appeared to be 50% for polyethylene and 60% for teflon. The main merit of the technique is assumed to be the simplicity of the measuring instruments [ru

Surface modification of polyethylene terephthalate using excimer and CO2 laser

International Nuclear Information System (INIS)

Mirzadeh, H.; Dadsetan, M.

2002-01-01

Complete text of publication follows. Attempts have been made to evaluate microstructuring which affects cell behaviour, physical and chemical changes produced by laser irradiation onto the polyethylene terephthalate (PET) surface. The surfaces of PET were irradiated using the CO 2 laser and KrF excimer pulsed laser. The changes in chemical and physical properties of the irradiated PET surface were investigated by attenuated total reflectance infrared spectroscopy (ATR-IR) and contact angle measurements. ATR-IR Spectra showed that the crystallinity in the surface region decreased due to the CO 2 laser and excimer laser irradiation. Scanning electron microscopy observations showed that the morphology of the laser irradiated PET surface changed due to laser irradiation. The results obtained from the cell behaviour studies revealed that changes of physico-chemical properties of the laser treated PET film have significantly changed in comparison with the unmodified PET

Measurements of free radical in vitamin E-doped ultra-high molecular weight polyethylene: Dependence on materials processing and irradiation environments

Energy Technology Data Exchange (ETDEWEB)

Ridley, M.D. [Department of Physics, Biomaterials Research Laboratory, University of Memphis, 216 Manning Hall, Memphis, TN 38152 (United States); Jahan, M.S. [Department of Physics, Biomaterials Research Laboratory, University of Memphis, 216 Manning Hall, Memphis, TN 38152 (United States)], E-mail: mjahan@memphis.edu

2007-12-15

Ultra-high molecular weight polyethylene (UHMWPE), doped with vitamin E ({alpha}-tocopherol ({alpha}-T)), was irradiated with gamma rays in nitrogen (N{sub 2}) or air, and the resulting free radicals were detected in air using an electron spin resonance (ESR) technique. Two groups of samples were investigated. In one group, samples were prepared from blends of {alpha}-T (20 wt%) and UHMWPE powder (PPE-{alpha}-T) and, in the other, from compression molded blocks (CMPE-{alpha}-T). The CMPE-{alpha}-T blocks contained 0% (control), 0.5%, 1.0%, 10.0%, 15.0%, 20.0% and 25.0% {alpha}-T by weight. When irradiation was performed in air, the ESR spectrum of powder samples showed the presence of only vitamin E radical (tocopheroxyl, {alpha}-T-O{sup {center_dot}}), and there was no detectable signal due to PE radicals (alkyl/allyl). Most likely, all PE radicals were quenched by vitamin E during irradiation in air. However, when irradiation was performed in N{sub 2}, composite ESR spectra showed the presence of both PE and {alpha}-T-O{sup {center_dot}} radicals. Compared to the control (PPE, 0% {alpha}-T) PE radicals in PPE-20% {alpha}-T were found to be significantly reduced or quenched by {alpha}-T. The presence of {alpha}-T in powder samples, however, did not affect the long-term (71 days in this study) oxidation behavior of the PE radicals. Compression molded samples, with and without {alpha}-T, produced identical ESR spectra irrespective of their irradiation environment N{sub 2} or air. However, radical concentration, measured immediately after irradiation, was found to be an order of magnitude less in CMPE-{alpha}-T than in the control (CMPE-0% {alpha}-T). They also evidenced identical structural changes in the respective ESR spectra during subsequent oxidation for 24 days in open air. These observations suggest that {alpha}-T can effectively quench a significant fraction of PE radicals during irradiation, but has no measurable effect on subsequent reactions. No

Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

Science.gov (United States)

Khoylou, F.; Naimian, F.

2009-03-01

A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material.

Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

Energy Technology Data Exchange (ETDEWEB)

Khoylou, F. [Nuclear Science and Technology Research Institute, Radiation Applications Research School, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of)], E-mail: fkhoylou@aeoi.org.ir; Naimian, F. [Nuclear Science and Technology Research Institute, Radiation Applications Research School, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of)

2009-03-15

A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material.

Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

International Nuclear Information System (INIS)

Khoylou, F.; Naimian, F.

2009-01-01

A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material

The Mechanical Properties of Recycled Polyethylene-Polyethylene Terephthalate Composites

Directory of Open Access Journals (Sweden)

Ehsan Avazverdi

2015-02-01

Full Text Available Polyethylene terephthalate (PET, one of the thermoplastic polymers, is encountered with arduous problems in its recycling. After recycling, its mechanical properties drop dramatically and therefore it cannot be used to produce the products as virgin PET does. Polyethylene is a thermoplastic polymer which can be easily recycled using the conventional recycling processes. The decreased mechanical properties of virgin polyethylene due to the environmental factors can be improved by reinforcing fillers. In this paper, we studied the effects of adding recycled polyethylene terephthalate (rPET as a filler, in various amounts with different sizes, on the physical and mechanical properties of recycled polyethylene. Composite samples were prepared using an internal mixer at temperature 185°C, well below rPET melting point (250°C, and characterized by their mechanical properties. To improve the compatibility between different components, PE grafted with maleic anhydride was added as a coupling agent in all the compositions under study. The mechanical properties of the prepared samples were performed using the tensile strength, impact strength, surface hardness and melt flow index (MFI tests. To check the dispersity of the polyethylene terephthalate powder in the polyethylene matrix, light microscopy was used. The results showed that the addition of rPET improved the tensile energy, tensile modulus and surface hardness of the composites while reduced the melt flow index, elongation-at-yield, tensile strength and fracture energy of impact test. We could conclude that with increasing rPET percentage in the recycled polyethylene matrix, the composite became brittle, in other words it decreased the plastic behavior of recycled polyethylene. Decreasing particle size led to higher surface contacts, increased the mechanical properties and made the composite more brittle. The light microscopy micrographs of the samples showed a good distribution of small r

Preparation of ultrafiltration membrane by phase separation coupled with microwave irradiation

Energy Technology Data Exchange (ETDEWEB)

Suryani, Puput Eka [Department of Chemical Engineering, Faculty of Engineering, Diponegoro University Jl. Prof. Soedarto, Semarang 50275, Central Java (Indonesia); Department of Chemical Engineering, Faculty of Engineering, UniversitasMuhammadiyah Surakarta Jl. Jendral Ahmad Yani, Surakarta 57102, Central Java (Indonesia); Purnama, Herry [Department of Chemical Engineering, Faculty of Engineering, UniversitasMuhammadiyah Surakarta Jl. Jendral Ahmad Yani, Surakarta 57102, Central Java (Indonesia); Susanto, Heru, E-mail: heru.susanto@undip.ac.id [Department of Chemical Engineering, Faculty of Engineering, Diponegoro University Jl. Prof. Soedarto, Semarang 50275, Central Java (Indonesia)

2015-12-29

Preparation of low fouling ultrafiltration membrane is still a big challenge in the membrane field. In this paper, polyether sulfone (PES) ultrafiltration membranes were prepared by non-solvent-induced phase separation (NIPS) coupled with microwave irradiation. Polyethylene glycol (PEG) and polyethylene glycol methacrylate (PEGMA) were used as additives to improve membrane hydrophilicity. In this study, the concentration of additive, irradiation time and microwave power was varied. The membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, while the performances were tested by adsorptive and ultrafiltration fouling experiments. The results show that the irradiation time and irradiation power are very important parameter that influence the membrane characteristic. In addition, type and concentration of additive are other important parameters. The results suggest that microwave irradiation is the most important parameter influencing the membrane characteristic. Both pure water flux and fouling resistance increase with increasing irradiation time, power irradiation, and additive concentration. PES membrane with addition of 10% w/w PEG and irradiated by 130 W microwave power for 180 seconds is the best membrane performance.

Mechanical properties in polypropylene-polyethylene blends modified by gamma radiation

International Nuclear Information System (INIS)

Ruiz, F.C.; Terence, M.C.

2008-01-01

One of the way to obtain a better mechanical property of polypropylene and polyethylene is related to increase the number polymer chains cross-linked by gamma radiation. After irradiation a network is formed which is the result of various chemical reactions occurred during this process, where the radicals formed are concentrated in the amorphous phase. With the objective to increase the mechanical properties of PP, blends with PE were prepared and irradiated in doses up to 100kGy, in atmospheric ambient. The tests showed increase in rigidity and a particular behaviour in Izod impact resistance. (author)

Improvement of hygienic quality and long-term storage of dried red pepper by gamma irradiation

International Nuclear Information System (INIS)

Byun, M.W.; Yook, H.S.; Kwon, J.H.; Kim, J.O.

1996-01-01

Dried-red pepper, whole and powdered types, was subjected to a storage-study by investigation the effects of packaging methods (polycloth & polyethylene/polycloth, whole dried-red pepper; nylon/polyethylene-lam-inated film, red pepper powder), temperature and gamma irradiation doses (0-10 kGy). After 6 months storage in polyclith sack at ambient temperature, all whole dried-red pepper showed quality deterioration, such as weight change, insect infestation, discoloration and chemical changes, After 2 years storage in combined packaging with polyethylene/polycloth sack of 5-7.5 kGy irradiated whole dried-red pepper at ambient temperature, however, quality deterioration was not observed. Gamma-irradiated red pepper powder (7.5-10kGy) showed a good quality in hygienic, physicochemical and organoleptic evaluation after 2 years of storage at ambient temperature

Gamma irradiation technology for composite materials

International Nuclear Information System (INIS)

Romero, Guillermo R; Gonzalez, Maria E.

2003-01-01

A composite of sugar cane bagasse and low-density polyethylene was prepared. Gamma -radiation of Cobalt-60 (Co 60 ) and reactive additives were used, to make compatible the lignocellulosic fibers with the polymeric matrix. Gamma-radiation was applied in different stages with different purposes: a) Irradiation of cellulosic fibers treated or not with reactive additive, in presence of air, to produce macro radicals increasing their reactivity during extrusion with polyethylene. A homogeneous and fusible material resulted that can be used as raw material in thermoforming processes with cost in between that of its constitutive elements; b) Irradiation of final products, to produce the cross-linking of polymeric chains. The fibers remain trapped in the cross-linked matrix. A homogeneous and infusible material with high mechanical properties was obtained. (author)

Grafting of polyethylene films with acrylic acid and acrylonitril using gamma radiation

International Nuclear Information System (INIS)

Ajji, Z.; Al-Nesr, E.

2003-12-01

Acrylic acid (AAc) and acrylonitrile (AN) and their binary mixtures were graft copolymerized onto low density polyethylene (LDPE) films using gamma irradiation. The effects of different parameters on the graft yield were studies such as monomer concentration, inhibitor concentration, and irradiation dose. The obtained grafted films were characterized using FTIR spectroscopy, thermal gravimetry, and differential scanning calorimetry. Water uptake and the ion uptake were also evaluated, and the ability of grafted films to uptake heavy ions such as Ni 2+ and Cu 2+ was discussed. (author)

Tissue response to intraperitoneal implants of polyethylene oxide-modified polyethylene terephthalate.

Science.gov (United States)

Desai, N P; Hubbell, J A

1992-01-01

Polyethylene terephthalate films surface modified with polyethylene oxide of mol wt 18,500 g/mol (18.5 k) by a previously described technique, were implanted in the peritoneal cavity of mice, along with their respective untreated controls, for periods of 1-28 d. The implants were retrieved and examined for tissue reactivity and cellular adherence. The control polyethylene terephthalate surfaces showed an initial inflammatory reaction followed by an extensive fibrotic response with a mean thickness of 60 microns at 28 d. By contrast, polyethylene oxide-modified polyethylene terephthalate showed only a mild inflammatory response and no fibrotic encapsulation throughout the implantation period: at 28 d a cellular monolayer was observed. Apparently either the polyethylene oxide-modified surface was stimulating less inflammation, which was in turn stimulating less fibroblastic overgrowth, or the cellular adhesion to the polyethylene oxide-modified surface was too weak to support cellular multilayers.

Influence of freeze-drying and γ-irradiation in preclinical studies of flurbiprofen polymeric nanoparticles for ocular delivery using d-(+)-trehalose and polyethylene glycol.

Science.gov (United States)

Ramos Yacasi, Gladys Rosario; García López, María Luisa; Espina García, Marta; Parra Coca, Alexander; Calpena Campmany, Ana Cristina

This study investigated the suspension of poly(ε-caprolactone) nanoparticles as an ocular delivery system for flurbiprofen (FB-PεCL-NPs) in order to overcome the associated problems, such as stability, sterility, tolerance, and efficacy, with two different FB-PεCL-NP formulations. The formulations were stabilized with poloxamer 188 (1.66% and 3.5%) and submitted individually for freeze-drying and γ-irradiation with polyethylene glycol 3350 (PEG3350) and d-(+)-trehalose (TRE). Both formulations satisfied criteria according to all physicochemical parameters required for ocular pharmaceuticals. The FB-PεCL-NP formulations showed non-Newtonian behavior and sustained drug release. Ex vivo permeation analysis using isolated ocular pig tissues suggested that the presence of PEG3350 results in a reduction of FB transcorneal permeation. Moreover, TRE improved the penetration of FB across the cornea, especially after γ-irradiation. In addition, both formulations did not show a significant affinity in increasing FB transscleral permeation. Both formulations were classified as nonirritating, safe products for ophthalmic administration according to hen's egg test-chorioallantoic membrane and Draize eye test. Furthermore, an in vivo anti-inflammatory efficacy test showed that irradiated FB-PεCL-NPs prepared with PEG3350 (IR-NPsPEG) have longer anti-inflammatory effects than those presented with irradiated FB-PεCL-NPs prepared with TRE (IR-NPsTRE). IR-NPsPEG showed a suitable physical stability after an aqueous reconstitution over >30 days. This study concludes that both formulations meet the Goldman's criteria and demonstrate how irradiated nanoparticles, with innovative permeation characteristics, could be used as a feasible alternative to a flurbiprofen solution for ocular application in clinical trials.

Effect of radiation on the crystals of polyethylene and paraffins

International Nuclear Information System (INIS)

Ungar, G.; Grubb, D.T.; Keller, A.

1980-01-01

Paraffins were irradiated with electrons in the electron microscope. The electron microscopic image and the electron diffraction patterns were followed as a function of dose. The objectives were: (a) to establish a connection between the 'polyethylene-type' and 'paraffin-like' behaviour and (b) to identify the phase segregation, by visual means. Increasing chain length, increasing dose rate and decreasing temperature individually and in combination, were found to favour the 'polyethylene-type' behaviour (crystal destruction through increasing lattice defects) while the reverse trend of the above three variables favoured the 'paraffin-like' behaviour (phase-segregated damaged and undamaged species). Segregated phases could in some circumstances be identified as non-diffracting 'droplets' within a crystalline matrix, with the lattice hardly affected, in the electron microscopic image. These droplets remain constant in number but increase in size as the irradiation progresses, the number of droplets depending on the chain length of the paraffin, on the irradiation temperature and on the dose rate. This behaviour, together with some further observations, reveals that the radiation-induced active species do not form crosslinks in situ but migrate over distances which can amount to μm. In contrast to the above, in the case of the lowest paraffin investigated, (C 23 H 48 ), the lattice became uniformly distorted as judged from the diffraction pattern, but the damage was observed to 'heal-out' with time. The results are discussed. (author)

Cost evaluation of irradiation system with electron accelerator

International Nuclear Information System (INIS)

Kashiwagi, M.

2003-01-01

The features of electron beam irradiation system using electron accelerator are direct energy pour into the irradiated material, no third material mixture such as catalyst, suitable for mass production and easy operation and maintenance work available. These features can bring the various applications such as cross-linking action, graft polymerization, radical polymerization and others. The selection of electron accelerator ratings is made under consideration of quality, width and thickness of irradiated material, production amount, dose required for reaction and irradiation atmosphere. Especially in a case of irradiation of wire with high insulation material such as polyethylene, the consideration of maximum thickness toward irradiation direction is necessary to avoid the discharge (Lichtenberg discharge) by charged-up electrons inside insulation material. Therefore, the acceleration voltage should be selected to make the maximum penetration larger than maximum irradiation thickness. The actual model case of estimate the irradiation cost was selected that the irradiation object was polyethylene insulated wire up to AWG no.14, irradiation amount was 5,000 km/month, necessary dose was 200 kGy, operation time was 22 d/month and 8 h/day and actual operation efficiency was considered loss time such as bobbin changing as 80%. The selected ratings of electron accelerator were acceleration voltage of 800 kV, beam current of 100 mA and irradiation width of 180 cm with irradiation pulleys stand of 60 turns x 3 lanes. The initial total cost was estimated as 3 M$(US) and operation cost was evaluated as 215 k$(US). Therefore, the irradiation cost of wire was evaluated as 0.0036 $/m. (author)

Long-term durability of polyethylene for encapsulation of low-level radioactive, hazardous, and mixed wastes

International Nuclear Information System (INIS)

Kalb, P.D.; Heiser, J.H.; Colombo, P.

1991-01-01

The durability of polyethylene waste forms for treatment of low-level radioactive, hazardous, and mixed wastes is examined. Specific potential failure mechanisms investigated include biodegradation, radiation, chemical attack, flammability, environmental stress cracking, and photodegradation. These data are supported by results from waste form performance testing including compressive yield strength, water immersion, thermal cycling, leachability of radioactive and hazardous species, irradiation, biodegradation, and flammability. Polyethylene was found to be extremely resistant to each of these potential failure modes under anticipated storage and disposal conditions. 16 refs., 3 figs., 1 tab

Study of effects gamma radiation linear low density polyethylene (LLDPE) injected

International Nuclear Information System (INIS)

Oliveira, Ana Claudia Feitoza de

2014-01-01

The use of package sterilization through gamma radiation aim to reduce the microbiological contamination. The linear low density polyethylene (LLDPE) can be obtained by a process in solution, suspension or gaseous phase, depending on the type of the catalyzer used, that can be heterogeneous, or homogeneous, or metallocenes Ziegler-Natta. According to the literature, the gamma radiation presents a high penetration at polymeric materials causing the appearing of scissions, reticulation, and degradation when oxygen presence. This paper were irradiated with 60 Co with 2000 kCi of activity, in presence of air, samples of LLDPE injected. Utilized doses of 5, 10, 20, 50 or 100 kGy, and about 5 kGy.h -1 dose rates, at room temperature. After irradiation, the samples were heated for 60 min at 100 deg C to promote recombination and annihilation of residual radicals. For characterization of PEBLD were used methods; Melt flow index, swelling, gel fraction, Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (DRX), Thermogravimetric Analysis (TG), Dynamic Mechanical Analysis (DMA), rheological measurements, Scanning Electronic Microscopy and mechanical tests to identify the effects or gamma radiation in polyethylene. (author)

Biomimetic porous high-density polyethylene/polyethylene- grafted-maleic anhydride scaffold with improved in vitro cytocompatibility.

Science.gov (United States)

Sharma, Swati; Bhaskar, Nitu; Bose, Surjasarathi; Basu, Bikaramjit

2018-05-01

A major challenge for tissue engineering is to design and to develop a porous biocompatible scaffold, which can mimic the properties of natural tissue. As a first step towards this endeavour, we here demonstrate a distinct methodology in biomimetically synthesized porous high-density polyethylene scaffolds. Co-extrusion approach was adopted, whereby high-density polyethylene was melt mixed with polyethylene oxide to form an immiscible binary blend. Selective dissolution of polyethylene oxide from the biphasic system revealed droplet-matrix-type morphology. An attempt to stabilize such morphology against thermal and shear effects was made by the addition of polyethylene- grafted-maleic anhydride as a compatibilizer. A maximum ultimate tensile strength of 7 MPa and elastic modulus of 370 MPa were displayed by the high-density polyethylene/polyethylene oxide binary blend with 5% maleated polyethylene during uniaxial tensile loading. The cell culture experiments with murine myoblast C2C12 cell line indicated that compared to neat high-density polyethylene and high-density polyethylene/polyethylene oxide, the high-density polyethylene/polyethylene oxide with 5% polyethylene- grafted-maleic anhydride scaffold significantly increased muscle cell attachment and proliferation with distinct elongated threadlike appearance and highly stained nuclei, in vitro. This has been partly attributed to the change in surface wettability property with a reduced contact angle (∼72°) for 5% PE- g-MA blends. These findings suggest that the high-density polyethylene/polyethylene oxide with 5% polyethylene- grafted-maleic anhydride can be treated as a cell growth substrate in bioengineering applications.

Effects of ionizing radiation on the properties of ultra-high molecular weight polyethylene (PE-UHMW)

International Nuclear Information System (INIS)

Kurth, M.

1990-01-01

Ultra high molecular weight polyethylene (PE-UHMW) is used in most artificial joint replacement devices. Prior to implantation in biological environment, radiatin sterilization by 60 Co or electron beam is common. It is well known that polyethylene exposed to ionizing radiation of any sort undergo physical changes due to chain scission and/or crosslinking. PE-UHMW sheets, 8 mm thick, were either 60 Co or electron beam irradiated, in the range of 10-150 kGy under air or nitrogen atmoshere. The crystallinity of the irradiated samples increases with the irradiation dose. The chain scission/crosslinking events ratio determine the network structure and the sol/gel ratio. The latter was found to depend on irradiation dose, radiation atmosphere and sample thickness. Moreover 60 Co-irradiation is about 5 times more effective in forming PE-UHMW gel than electron-irradiation. Besides the degree of crosslinking, the molecular weight distribution is the main determinant of the structural properties of PE-UHMW. Low molecular weight fractions were also found. Using a dose of 30 kGy ( 60 Co in air), the average molecular weight of the soluble part after extraction decreased from originally 2.3 million g/mol to 170.000 g/mol, corresponding to a factor of about 10. These changes in molecular weight have a strong influence on the mechanical properties of PE-UHMW. Crosslinking slightly increases the yield strength, while the elongation at break decreases. Long-term compressive creep is reduced if the material is irradiated. Obviously, increased crystallinity after oxidative chain scission affects a higher deformation resistance. Radiation crosslinked structures cause a significant increase in abrasion resistance. The above described structural changes occur even upon irradiation of very low doses as used during sterilization. This study will enable to reduce the radiation sterilization damage and thus to gain long term stability of PE-UHMW medical devices. (orig./BBR)

Investigations of heavy ion tracks in polyethylene naphthalate films

CERN Document Server

Starosta, W; Sartowska, B; Buczkowski, M

1999-01-01

The heavy ion beam (with fluence 3x10 sup 8 ion/cm sup 2) from a cyclotron has been used for irradiation of thin polyethylene naphthalate (PEN) films. Latent tracks in these polymeric films have been sensitized by UV radiation and then chemically etched in NaOH solution. The etching process parameters have been controlled by the electroconductivity method. After etching, parameters of samples have been examined by SEM and bubble point methods (Coulter[reg] Porometer II instrument). Results have shown good quality of PEN track membranes with pore sizes in the range: 0.1 - 0.5 mu m. The described procedure is known for thin polyethylene terephthalate (PET) films. Taking into consideration that PEN films have got better mechanical, thermal, gas barrier as well as better chemical resistance properties in comparison with PET films, the possibility of application of such membranes is much wider.

Influence of laser surface modifying of polyethylene terephthalate on fibroblast cell adhesion

International Nuclear Information System (INIS)

Mirzadeh, H.; Dadsetan, M.

2003-01-01

Attempts have been made to evaluate the changes in physical and chemical properties of the polyethylene terephthalate (PET) surface due to laser irradiation. These changes have been investigated from viewpoints of microstructuring and its effect on fibroblast cell behavior. The surfaces of PET were irradiated using CO 2 and KrF excimer pulsed laser. The changes were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and contact angle measurements. The data from ATR-FTIR spectra showed that the crystallinity in the surface region decreased due to the CO 2 and excimer laser irradiation. SEM observations showed that specific microstructures were created on the PET surface due to laser irradiation. In order to study biocompatibility and cell behavior, we utilized standard in vitro L929-fibroblast cell culture system. Fibroblast cell adhesion and spreading were significantly correlated to the morphology and wettability of the laser irradiated PET surface

Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

International Nuclear Information System (INIS)

Nho, Y.C.; Mook Lim, Youn; Moo Lee, Young

2004-01-01

pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mmx3 mmx2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract

Radiation induced functionalism of polyethylene and ground tire rubber for their reactive compatibility in thermoplastic elastomers

Energy Technology Data Exchange (ETDEWEB)

Fainleib, A.; Grigoryeva, O. [Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Kiev 02160 (Ukraine); Martinez B, G. [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados, Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Km. 12 Carretera Toluca-Atlacomulco, San Cayetano 50200, Estado de Mexico (Mexico)], e-mail: fainleib@i.kiev.ua

2009-07-01

Reactive compatibility of recycled low-or high-density polyethylenes (LDPE and HDPE, respectively) and ground tire rubber (GTR) via chemical interactions of pre-functionalized components in their blend interface has been carried out. Polyethylene component was functionalized with maleic anhydride (MAH) as well as the rubber component was modified via functionalism with MAH or acrylamide using chemically or irradiation ({gamma} rays) induced grafting techniques. Additional coupling agents such as-p-phenylene diamine (PDA) and polyamide fiber (PAF, from fiber wastes) were used for some thermoplastic elastomer (TPE) producing. The grafting degree and molecular mass distribution of the chromatography analyses, respectively. TPE materials based on synthesized reactive polyethylenes and GTR as well as ethylene-propylene-diene monomer rubber were prepared by dynamic vulcanization of the rubber phase inside thermoplastic (polyethylene) matrix and their phase structure, and main properties have been studied using DSC, TGA, DMTA and mechanical testing. As a final result, the high performance TPE with improved mechanical properties has been developed. (Author)

Shipboard-irradiation of haddock

International Nuclear Information System (INIS)

Ehlermann, D.; Reinacher, E.; Antonacopoulos, N.

1977-01-01

Haddock caught during the 183rd and 185th voyage of the RV 'Anton Dohrn' off Faeroeer was gutted, washed and packed under vacuum in polyethylene pouches. The samples were irradiated with the onboard X-ray source. During one series of experiments a minimum dose of 65 krad and a maximum dose of 130 krad was used. During further series the minimal dose was set to 100 krad, resulting in maximum values of 140 krad and 180 krad. As judged by taste panel evaluation of steam-cooked, unseasoned filets, quality preservation of all samples during the first 16 days of iced storage did not depend on irradiation. After that period the fish had lost prime quality. At this time, irradiated samples were rated slightly better than unirradiated ones. Base on our results, the shipboard-irradiation of prepacked haddock cannot be recommended. This does not exclude that under different conditions (e.g. fishfilets in retail packages) beneficial effects of irradiation may be observed. (orig.) [de

XPS analysis of PE and EVA samples irradiated at different γ-doses

Science.gov (United States)

Dorey, Samuel; Gaston, Fanny; Marque, Sylvain R. A.; Bortolotti, Benjamin; Dupuy, Nathalie

2018-01-01

The principal plastic materials used for the fluid contact and storage in the biopharmaceutical industry are mainly made up of semi-crystalline polymers, polyolefins, PVC, Siloxane and PET. The polyethylene (PE) and the polypropylene (PP) are often used as fluid contact in multi-layer materials like films. As one sterilisation way of single-use plastic devices used in medical and pharmaceutical fields can take place via γ-irradiation, the effect of sterilization on plastics must be investigated. The irradiation process leads to the production of radicals, which can generate changes in the polymer structure and on the polymer surface. It is well known that the presence of oxygen with free radicals precede the generation of peroxide species so called ROS (reactive oxygen species) which are highly reactive. The purpose of this work is to investigate the γ-rays impact on the surface of PE (polyethylene) and EVA (polyethylene vinyl alcohol) based films when ionized at different doses. X-ray Photoelectron Spectroscopy (XPS) was applied to determine the surface compositions of the polymers to highlight the different chemical moieties generated during the γ-irradiation process and to monitor the potential presence of the ROS.

Study on thermal properties and crystallization behavior of electron beam irradiated ethylene vinyl acetate (EVA)/waste tyre dust (WTD) blends in the presence of polyethylene graft maleic anhydride (PEgMAH)

Energy Technology Data Exchange (ETDEWEB)

Ramli, Syuhada; Ahmad, S. H. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan (Malaysia); Ratnam, C. T. [Radiation Processing Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang (Malaysia); Athirah, Nurul [School of Materials and Mineral Resources, USM Engineering Campus (Malaysia)

2013-11-27

The aim of this article is to show the effects of the electron beam irradiation dose and presence of a compatibiliser on the thermal properties and crystallinity of EVA/WTD blends. The purpose of applying electron beam radiation with doses range 50 to 200 kGy and adding a compatibiliser was to enhance the compatibility of the studied blends and at the same time to investigate the possibility of using this technique in the process of recycling polymeric materials. As the compatibilisers, the polyethylene grafted maleic anhydride (PEgMAH) was utilized, they were added at the amounts of 1-5 phr respectively. The enhancement of thermal properties was accompanied by the following effects, discussed in this article: i) an irradiated EVA/WTD blend at 200kGy was found to improve the thermal properties of EVA, ii) the addition of PEgMAH in EVA/WTD blends and the subsequent irradiation allowed prevention of degradation mechanism. iii) the ΔH{sub f} and crystallinity percentage decrease at higher PEgMAH content.

PEG-albumin plasma expansion increases expression of MCP-1 evidencing increased circulatory wall shear stress: an experimental study.

Directory of Open Access Journals (Sweden)

C Makena Hightower

Full Text Available Treatment of blood loss with plasma expanders lowers blood viscosity, increasing cardiac output. However, increased flow velocity by conventional plasma expanders does not compensate for decreased viscosity in maintaining vessel wall shear stress (WSS, decreasing endothelial nitric oxide (NO production. A new type of plasma expander using polyethylene glycol conjugate albumin (PEG-Alb causes supra-perfusion when used in extreme hemodilution and is effective in treating hemorrhagic shock, although it is minimally viscogenic. An acute 40% hemodilution/exchange-transfusion protocol was used to compare 4% PEG-Alb to Ringer's lactate, Dextran 70 kDa and 6% Hetastarch (670 kDa in unanesthetized CD-1 mice. Serum cytokine analysis showed that PEG-Alb elevates monocyte chemotactic protein-1 (MCP-1, a member of a small inducible gene family, as well as expression of MIP-1α, and MIP-2. MCP-1 is specific to increased WSS. Given the direct link between increased WSS and production of NO, the beneficial resuscitation effects due to PEG-Alb plasma expansion appear to be due to increased WSS through increased perfusion and blood flow rather than blood viscosity.

Effects of chemical and gamma irradiation environments on the mechanical properties of high-density polyethylene (HDPE)

International Nuclear Information System (INIS)

Soo, P.

1988-01-01

High-density polyethylene (HDPE) is currently being used as a high-integrity container material for low-level wastes. Potential failure/degration modes must be determined for realistic environmental conditions. These include consideration of mechanical stress, gaseous/liquid environments within and external to the container, and the gamma radiation field. A combination of simple inexpensive tests (stressed U-bend samples) and more sophisticated longer-term uniaxial creep tests are being used to define the ranges of conditions for which mechanical failure/degradation is important. Test environments include Igepal CO-630, turbine oil and liquid scintillation fluid as well as air and deionized water, the control environments. Igepal CO-630 is a surfactant specified in standard ASTM tests for environmental stress cracking. Turbine oil is a possible constituent of low-level waste generated at reactor power plants, and is used in the current tests because of its known detrimental behavior to many types of plastic. Liquid scintillation fluids are being evaluated here because they are representative of the class of organiz solvents containing toluene and xylene. As such they will give valuable insights regarding a type of potential failure or degradation mode for HDPE. The effect of gamma irradiation on crack initiation and propagation is also being studied. A description of the work and results are presented. 8 refs., 6 figs., 2 tabs

Structure and properties of UV-irradiated LLDPE and alloy of PA66 and the irradiated LLDPE

International Nuclear Information System (INIS)

Ran Qianping; Zou Hua; Wu Shishan; Shen Jian

2006-01-01

Some oxygen-containing groups such as C=O, C-O and -OH were introduced onto linear low-density polyethylene (LLDPE) chains by UV irradiation in air. Their concentration increased with the irradiation time. Crystal shape of the irradiated LLDPE remained an orthorhombic structure, while space of the crystalline plane kept unchanged. The melting temperature and crystallinity decreased due to the LLDPE chain scission into small molecules compound and crystalline defects caused by UV irradiation. Compared with pristine LLDPE, hydrophilicity of the irradiated LLDPE increased due to the introduction of polar oxygen-containing groups, but the tensile strength decreased due to the LLDPE chain degradation and reduction of crystallinity. The temperature of initial weight loss of the irradiated LLDPE was lower than that of pristine LLDPE. An alloy of PA66 and the irradiated LLDPE (irradiated PA66/LLDPE) was prepared by melting blend at 260-270 degree C. Compared to non-irradiated PA66/LLDPE alloy, dispersion of LLDPE particles in the irradiated PA66/LLDPE alloy and interfacial interactions between the components were markedly improved. Therefore, tensile strength and impact strength of the irradiated PA66/ LLDPE were higher than those of the control. (authors)

Physical and mechanical properties of gamma radiation cross-linked polyethylene

International Nuclear Information System (INIS)

Gonzalez, Maria E.; Romero, G.; Smolko, Eduardo E.

1999-01-01

Granulated LDPE 2003 polyethylene was extruded and irradiated under nitrogen with 150, 200 and 300 kGy gamma rays doses to produce cross-linking. The study of the physical and mechanical properties shows that the product has a high degree of molecular cross-linking, can be heated up to 200 C for 2 hours without deformation and that the mechanical properties improve. Preliminary aging tests indicate that after heating at 60 C for 4 weeks no physical or mechanical deterioration can be observed. (author)

Effect of electron beam radiation on the structure and mechanical properties of ultra high molecular weight polyethylene fibers

International Nuclear Information System (INIS)

Li Shujun; Sun Weijun; Liu Xiuju; Gao Yongzhong; Li Huisheng

1998-01-01

Ultra high molecular weight polyethylene fibers have been crosslinked by electron beam. The structure and mechanical properties of them have been investigated in different irradiation atmospheres. The obtained results show that the gel content and crosslinking density increase with the increase of dose, the swelling ratio and average molecular weight of crosslinked net decrease with the increase of dose, the tensile strength and failure elongation decrease with the increase of dose, the tensile modulus increases with the increase of dose. When the samples are irradiated in air, vacuum and acetylene atmospheres, the effect of irradiation in acetylene atmosphere is best

Irradiation of ground beef with the purpose of refrigerated storage

International Nuclear Information System (INIS)

Keskin, S.

1977-01-01

Ground beef packaged in polyethylene film was irradiated at different dose levels ranging from 0.25 to 1.0 Mrad and stored at 3+-1 0 C. Bacteriological and organoleptic evaluations were carried out immediately after irradiation and at weekly intervals thereafter. The red color of the meat was darker after irradiation and this darkening increased with radiation dose. This color change was limited to the surface of the samples. The results of the bacteriological and organoleptic examination indicate that irradiation at 0.25 Mrad permits refrigerated storage of ground beef for 3 weeks, 0,5 Mrad for 6 weeks. Coliforms were found only in non-irradiated samples [fr

Structural modifications of swift heavy ion irradiated PEN probed by optical and thermal measurements

International Nuclear Information System (INIS)

Devgan, Kusum; Singh, Lakhwant; Samra, Kawaljeet Singh

2013-01-01

Highlights: • The present paper reports the effect of swift heavy ion irradiation on Polyethylene Naphthalate (PEN). • Swift heavy ion irradiation introduces structural modification and degradation of PEN at different doses. • Lower irradiation doses in PEN result in modification of structural properties and higher doses lead to complete degradation. • Strong correlation between structural, optical, and thermal properties. - Abstract: The effects of swift heavy ion irradiation on the structural characteristics of Polyethylene naphthalate (PEN) were studied. Samples were irradiated in vacuum at room temperature by lithium (50 MeV), carbon (85 MeV), nickel (120 MeV) and silver (120 MeV) ions with the fluence in the range of 1×10 11 –3×10 12 ions cm −2 . Ion induced changes were analyzed using X-ray diffraction (XRD), Fourier transform infra red (FT-IR), UV–visible spectroscopy, thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. Cross-linking was observed at lower doses resulting in modification of structural properties, however higher doses lead to the degradation of the investigated polymeric samples

The study of mildew proof effect of 60Co γ irradiation on leather shoes

International Nuclear Information System (INIS)

Wu Caixuan; Deng Zhiqun; Yu Qin; Zeng Daonan; Deng Guili

1992-01-01

Leather products occupy an important place in the national economy. In order to prevent from mildewing of leather products in storage, transportation and sale, the packed shoes were irradiated with 60 Co γ ray. Test materials are cattle, sheep and pig leather shoes. The results shows that: 1. There are 11 types of molds which make leather shoes mildewed: Oospora sp, Rhizopus oryzae Went and Grrelings, Aspergillus flavus Link, Aspergillus terreus thom, Monilia sp, Botrytis sp, Aspergillus niger V. Tiegh, Penicillum Lividum Westling, Penicillum Corylophilum Dieckx, Penicillum Cyaneum (B. and S.) Biourge and Penicillum Verrulosum Peeyrone. 2. The three types of shoes packed with polyethylene film can be prevented from mildewing after irradiation at level of 12 kGy. 3. The irradiation at 30 kGy does not change the physical properties of the shoes. 4. The irradiated shoes packed with polyethylene film can prevent mildewing, but unpacked ones would be mildewed again

Comparison of the effect of gamma irradiation, heat-radiation combination, and sulphur dioxide generating pads on decay and quality of grapes

International Nuclear Information System (INIS)

Thomas, Paul; Brij Bhushan; Joshi, M.R.

1995-01-01

Effect of gamma irradiation, heat-radiation combination and in-package sulphur dioxide fumigation on fungal decay, and quality of seedless grape cultivars, Thompson, Sonaka and Tas-A-Ganesh was evaluated under different storage regimes. Irradiation at 2 kGy or a combination of hot water dip (50 degC, 5 min), plus irradiation (1 kGy) showed less spoilage due to Rhizopus spp. and Botrytis spp. in grapes packaged in tissue paper lined boxes and stored at 4 deg, 15 deg and 25 degC. Storage in polyethylene lined boxes increased the fungal rot. In-package sulphur dioxide generating pad was most effective for control of decay in polyethylene lined boxes stored at 10 deg and 20 degC, but caused berry bleaching. Irradiation at 2.5 or 3.5 kGy controlled decay at 10 degC, but not so effectively at 20 degC. Organoleptic quality, berry firmness, and soluble solids were not affected by irradiation, but decreases in titratable acids and ascorbic acid were recorded. Packaging in polyethylene lined boxes retained berry turgidity, while slight shrivelling occurred in tissue paper lined boxes. The results indicate that gamma irradiation has potential as an alternative to sulphur dioxide fumigation for decay control during shipping and storage. (author). 20 refs., 4 tabs

Effect of gamma irradiation on some nutritional factors of rice

International Nuclear Information System (INIS)

Mohamad Khan Ayob; Osman Hassan.

1987-01-01

The effect of gamma irradiation and types of packaging material used (namely: gunny sack, heavy duty polyethylene, woven laminated bags) on moisture content, gel viscosity and reducing sugar of rice was observed. Moisture content, gel viscosity and reducing sugar were determined by drying method, brookfield viscometer and Nelson method, respectively. The results showed that moisture and reducing sugar content were not significantly affected by types of material and irradiation doses. On the other hand gel viscosity was greatly influenced by irradiation doses and storage time. (A.J.)

The radiation sterilisation of pyrogen-free water in polyethylene sachets

International Nuclear Information System (INIS)

Du Plessis, T.A.

1977-06-01

The radiation sterilization of pyrogen-free water in polyester/polyethylene-laminate sachets was investigated. A technique was developed to ensure the sterile removal of the water from the sachet. The production of hydrogen peroxide as the major radiolytic product was investigated for water irradiated in both glass vials and polymer sachets. It was found that the formation of hydrogen peroxide in the polymer sachets was only half of that formed in the glass vials. The radiation-sterilised water was found to comply in all respects with the British Pharmacopoeia requirements for water for injections [af

Solid-phase photocatalytic degradation of polyethylene film with manganese oxide OMS-2

Science.gov (United States)

Liu, Guanglong; Liao, Shuijiao; Zhu, Duanwei; Cui, Jingzhen; Zhou, Wenbing

2011-01-01

Solid-phase photocatalytic degradation of polyethylene (PE) film with cryptomelane-type manganese oxide (OMS-2) as photocatalyst was investigated in the ambient air under ultraviolet and visible light irradiation. The properties of the composite films were compared with those of the pure PE film through performing weight loss monitoring, IR spectroscopy, scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS). The photoinduced degradation of PE-OMS-2 composite films was higher than that of the pure films, while there has been little change under the visible light irradiation. The weight loss of PE-OMS-2 (1.0 wt%) composite films steadily decreased and reached 16.5% in 288 h under UV light irradiation. Through SEM observation there were some cavities on the surface of composite films, but few change except some surface chalking phenomenon occurred in pure PE film. The degradation rate with ultraviolet irradiation is controllable by adjusting the content of OMS-2 particles in PE plastic. Finally, the mechanism of photocatalytic degradation of the composite films was briefly discussed.

Effect of Zinc Oxide Nanoparticles and Sodium Hydroxide on the Self-Cleaning and Antibacterial Properties of Polyethylene Terephthalate

Directory of Open Access Journals (Sweden)

Mohammad Mirjalili

2017-12-01

Full Text Available In this study, the synthesis of zinc oxide nanoparticles was carried out, together with the hydrolysis of polyethylene terephthalate, using sodium hydroxide to increase surface activity and enhance nanoparticle adsorption. Polyester fabrics were treated with zinc acetate and sodium hydroxide in an ultrasonic bath, resulting in the formation of ZnO nanospheres. The presence of zinc oxide on the surface of the polyethylene terephthalate was confi rmed using scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDS. The self-cleaning property of treated fabrics was evaluated through discolouring using methylene blue stain under solar irradiation. The antibacterial activities of the samples against common pathogenic bacteria, including Escherichia coli and Staphylococcus aureus, were also assessed. The results indicated that the photocatalytic and antibacterial activities of the ultrasound-treated polyethylene terephthalate improved significantly.

Effect of gamma irradiation on physico-mechanical properties of spice packaging films

Energy Technology Data Exchange (ETDEWEB)

Mizani, Maryam [Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, P.O. Box 14155-4933, Tehran (Iran, Islamic Republic of)], E-mail: mizani1_2000@yahoo.com; Sheikh, Nasrin [Nuclear Science and Technology Research Institute, Radiation Application Research School, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of); Ebrahimi, Samad N. [Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, P.O. Box 19835-389, Tehran (Iran, Islamic Republic of); Gerami, Abas [School of Mathematics, Statistics and Computer Science, University of Tehran, P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of); Tavakoli, Farnaz A. [Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, P.O. Box 14155-4933, Tehran (Iran, Islamic Republic of)

2009-09-15

Physico-mechanical properties of two types of laminated films, commercially used for spice packaging, are investigated after gamma irradiation at 8, 10 and 15 kGy. Data showed that polyethylene terephthalate/polyethylene terephthalate/linear low density polyethylene (PET/PET/LLDPE) was more resistant to radiation compared to biaxially oriented polypropylene/cast polypropylene (BOPP/CPP) and its barrier properties slightly improved up to 15 kGy. Oxygen transmission rate of BOPP/CPP was increased by 25%, and the melting peak temperature was decreased by 3.9% at 15 kGy, which may lead to oxidation of packaged spices and loss of their aroma/flavour, respectively.

Effect of gamma irradiation on physico-mechanical properties of spice packaging films

International Nuclear Information System (INIS)

Mizani, Maryam; Sheikh, Nasrin; Ebrahimi, Samad N.; Gerami, Abas; Tavakoli, Farnaz A.

2009-01-01

Physico-mechanical properties of two types of laminated films, commercially used for spice packaging, are investigated after gamma irradiation at 8, 10 and 15 kGy. Data showed that polyethylene terephthalate/polyethylene terephthalate/linear low density polyethylene (PET/PET/LLDPE) was more resistant to radiation compared to biaxially oriented polypropylene/cast polypropylene (BOPP/CPP) and its barrier properties slightly improved up to 15 kGy. Oxygen transmission rate of BOPP/CPP was increased by 25%, and the melting peak temperature was decreased by 3.9% at 15 kGy, which may lead to oxidation of packaged spices and loss of their aroma/flavour, respectively.

Ten years' operation of an irradiation unit

International Nuclear Information System (INIS)

Icre, Pierre

1979-01-01

The Ionizing Radiation Application Center is equipped with an electron linear accelerator for diversified applications. Power of the electron beam is 7.5 kW and energy is 6 MeV. Main activity is radiosterilization of disposable medical and surgical materials. Remaining activity is irradiation of plastic especially grafting and cross-linking of polyethylene [fr

Sterilization of ground spices by electron beams irradiation

Energy Technology Data Exchange (ETDEWEB)

Hashigiwa, Masayuki; Nakachi, Ayako; Kobayashi, Hiroshi [K. Kobayashi and Co., Ltd., Kako, Hyogo (Japan)

1999-09-01

Each ground spice (Black Pepper, Turmeric, Ginger, Paprika and Basil), which was packaged into polyethylene film, was irradiated by electron beams at 5 different levels: 2, 4, 6, 8 and 10 kGy. Bacteriological tests for total bacterial count were carried out on spices before and after irradiation, but the tests for microfiora were carried out only before irradiation. Total bacterial count decreased in proportion to the level of electron beams. But the decreasing rate for Turmeric, Ginger and Basil was lower compared with that of other spices. The reason seems that rate of contamination by B. pumilus, which is thought as radiation resistant bacteria, was higher on these spices. (author)

Sterilization of ground spices by electron beams irradiation

International Nuclear Information System (INIS)

Hashigiwa, Masayuki; Nakachi, Ayako; Kobayashi, Hiroshi

1999-01-01

Each ground spice (Black Pepper, Turmeric, Ginger, Paprika and Basil), which was packaged into polyethylene film, was irradiated by electron beams at 5 different levels: 2, 4, 6, 8 and 10 kGy. Bacteriological tests for total bacterial count were carried out on spices before and after irradiation, but the tests for microfiora were carried out only before irradiation. Total bacterial count decreased in proportion to the level of electron beams. But the decreasing rate for Turmeric, Ginger and Basil was lower compared with that of other spices. The reason seems that rate of contamination by B. pumilus, which is thought as radiation resistant bacteria, was higher on these spices. (author)

Chemical modification of high molecular weight polyethylene through gamma radiation for biomaterials applications; Modificacao quimica de polietileno de alto peso molecular atraves de radiacao gama para aplicacao em biomateriais

Energy Technology Data Exchange (ETDEWEB)

Raposo, Matheus P.; Rocha, Marisa C.G., E-mail: matheusmerlim@hotmail.com [Universidade Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico

2015-07-01

Ultra high molecular weight polyethylene has been used in the medical field due to its high mechanical properties compared to the other polymers. Its main application is in the development of orthopedic implants, which requires high resistance to abrasion. One of the most used methods is the introduction of crosslinks in the polymer through gamma irradiation. In order to prevent oxidation reactions, studies have been developed using tacoferol (vitamin E) as an antioxidant for the material. The ascorbic acid (vitamin C), however, has been appointed as a viable alternative for vitamin E. In this work, a high molecular weight polyethylene grade (HMWPE) and polyethylene samples formulated with vitamin C were submitted to gamma radiation. Thermodynamic-mechanical methods and gel content determinations were used to characterize the samples obtained. The sample containing 1% of vitamin C and irradiated with 50 KGy of gamma radiation presented the highest content of crosslinks. (author)

Application of irradiation techniques to food and foodstuffs

International Nuclear Information System (INIS)

Kwon, Joong Ho; Byun, Myung Woo; Kim, Suc Won; Yang, Jae Seung; Cho, Han Ok

1991-02-01

A preservation study of dried fish, anchovies, has been conducted to determine the effect of gamma irradiation and laminated(nylon/polyethylene) film packaging on microbiological, physicochemical and organoleptic qualities of stored samples under room, refrigeration and freezing temperatures. Irradiation at less than 5 kGy and NY/PE-laminated film packaging are anticipated to be significantly effective for over 10 months in terms of improving the hygienic quality and extending the storage life of boiled-dried anchovies. In a survey participating 700 consumers, respondents preferred irradiated food to chemically-treated one. However, majority of respondents (55.7 %) was ignorant of the fact that the Korean government and international organizations concerned have approved the wholesomeness of irradiated food. Insufficiency of public information and understanding for irradiated food was indicated as a major cause for retardation of commercial utilization of food irradiation technology. In a response concerning perception and acceptance toward irradiated food, there was a significant difference between radiation worker and the general public. (Author)

Method for shaping polyethylene tubing

Science.gov (United States)

Kramer, R. C.

1981-01-01

Method forms polyethylene plastic tubing into configurations previously only possible with metal tubing. By using polyethylene in place of copper or stain less steel tubing inlow pressure systems, fabrication costs are significantly reduced. Polyethylene tubing can be used whenever low pressure tubing is needed in oil operations, aircraft and space applications, powerplants, and testing laboratories.

Polyethylene encapsulatin of nitrate salt wastes: Waste form stability, process scale-up, and economics

International Nuclear Information System (INIS)

Kalb, P.D.; Heiser, J.H. III; Colombo, P.

1991-07-01

A polyethylene encapsulation system for treatment of low-level radioactive, hazardous, and mixed wastes has been developed at Brookhaven National Laboratory. Polyethylene has several advantages compared with conventional solidification/stabilization materials such as hydraulic cements. Waste can be encapsulated with greater efficiency and with better waste form performance than is possible with hydraulic cement. The properties of polyethylene relevant to its long-term durability in storage and disposal environments are reviewed. Response to specific potential failure mechanisms including biodegradation, radiation, chemical attack, flammability, environmental stress cracking, and photodegradation are examined. These data are supported by results from extensive waste form performance testing including compressive yield strength, water immersion, thermal cycling, leachability of radioactive and hazardous species, irradiation, biodegradation, and flammability. The bench-scale process has been successfully tested for application with a number of specific ''problem'' waste streams. Quality assurance and performance testing of the resulting waste form confirmed scale-up feasibility. Use of this system at Rocky Flats Plant can result in over 70% fewer drums processed and shipped for disposal, compared with optimal cement formulations. Based on the current Rocky Flats production of nitrate salt per year, polyethylene encapsulation can yield an estimated annual savings between $1.5 million and $2.7 million, compared with conventional hydraulic cement systems. 72 refs., 23 figs., 16 tabs

Polyethylene-Based Tadpole Copolymers

KAUST Repository

Alkayal, Nazeeha; Zhang, Zhen; Bilalis, Panayiotis; Gnanou, Yves; Hadjichristidis, Nikolaos

2017-01-01

Novel well-defined polyethylene-based tadpole copolymers ((c-PE)-b-PS, PE: polyethylene, PS: polystyrene) with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser

Thermogravimetric studies of the thermooxidative stability of irradiated and unirradiated polyethylene

International Nuclear Information System (INIS)

Gal, O.; Novakovic, Lj.; Stannett, V.T.

1983-01-01

The addition of antioxidants to polymers increases their thermooxidative stability as indicated by a delay and/or a retardation of degradation. The present paper considers the influence of the nature of the antioxidant (hindered phenols, aromatic amines, and organic compounds containing sulphur atoms) on the thermooxidative behaviour of a low density polyethylene at 200 deg C. The following characteristics have been measured in polymer samples with zero; 0.1; 0.5; and 1.0 wt% content of antioxidant: the induction time of the oxidation process, rate of autoxidation and rate of polymer degradation (up to about 20% weight loss). The difference in thermal stability in radiation crosslinked material and comparative retardation of the thermooxidative degradation is observed up to an absorbed dose of 200 kGy. (author)

POLYETHYLENE ENCAPSULATION

International Nuclear Information System (INIS)

Kalb, P.

2001-01-01

Polyethylene microencapsulation physically homogenizes and incorporates mixed waste particles within a molten polymer matrix, forming a solidified final waste form upon cooling. Each individual particle of waste is embedded within the polymer block and is surrounded by a durable, leach-resistant coating. The process has been successfully applied for the treatment of a broad range of mixed wastes, including evaporator concentrate salts, soil, sludges, incinerator ash, off-gas blowdown solutions, decontamination solutions, molten salt oxidation process residuals, ion exchange resins, granular activated carbon, shredded dry active waste, spill clean-up residuals, depleted uranium powders, and failed grout waste forms. For waste streams containing high concentrations of soluble toxic metal contaminants, additives can be used to further reduce leachability, thus improving waste loadings while meeting or exceeding regulatory disposal criteria. In this configuration, contaminants are both chemically stabilized and physically solidified, making the process a true stabilization/solidification (S/S) technology. Unlike conventional hydraulic cement grouts or thermosetting polymers, thermoplastic polymers such as polyethylene require no chemical. reaction for solidification. Thus, a stable, solid, final waste form product is assured on cooling. Variations in waste chemistry over time do not affect processing parameters and do not require reformulation of the recipe. Incorporation of waste particles within the polymer matrix serves as an aggregate and improves the mechanical strength and integrity of the waste form. The compressive strength of polyethylene microencapsulated waste forms varies based on the type and quantity of waste encapsulated, but is typically between 7 and 17.2 MPa (1000 and 2500 psi), well above the minimum strength of 0.4 MPa (160 psi) recommended by the U.S. Nuclear Regulatory Commission (NRC) for low-level radioactive waste forms in support of 10 CFR 61

Experimental evaluation of the neutrons flux of a irradiator with AmBe sources and its possibility of use in materials analysis

International Nuclear Information System (INIS)

Lima, Ruy Barros de

2003-01-01

This work had as a target to determine the irradiator thermal and over cadmium (epithermal and fast) neutrons flux , of the Nuclear Experimental Laboratory of the Nuclear Energy Center (CNEN) - IPEN, and the possibility of its use for Neutron Activation Analysis (NAA) by the absolute method. The neutrons flux quantification was performed indirectly by the gold naked and cadmium-covered foils activation technique. The neutrons flux was determined for two situations: with polyethylene block 5.0 cm thick and without the polyethylene block. The quantification of the elements present in the irradiated samples was obtained after the experimental determination of the incident neutrons flux in the irradiation position of the sample. Flux values along the irradiator axis were determined. Some materials were analyzed, presenting good agreement with reference values. (author)

Oil-Impregnated Polyethylene Films

Science.gov (United States)

Mukherjee, Ranit; Habibi, Mohammad; Rashed, Ziad; Berbert, Otacilio; Shi, Shawn; Boreyko, Jonathan

2017-11-01

Slippery liquid-infused porous surfaces (SLIPS) minimize the contact angle hysteresis of a wide range of liquids and aqueous food products. Although hydrophobic polymers are often used as the porous substrate for SLIPS, the choice of polymer has been limited to silicone-based or fluorine-based materials. Hydrocarbon-based polymers, such as polyethylene, are cost effective and widely used in food packaging applications where SLIPS would be highly desirable. However, to date there have been no reports on using polyethylene as a SLIPS substrate, as it is considered highly impermeable. Here, we show that thin films of low-density polyethylene can be stably impregnated with carbon-based oils without requiring any surface modification. Wicking tests reveal that oils with sufficient chemical compatibility follow Washburn's equation. The nanometric effective pore size of the polyethylene does result in a very low wicking speed, but by using micro-thin films and a drawdown coater, impregnation can still be completed in under one second. The oil-impregnated polyethylene films promoted ultra-slippery behavior for water, ketchup, and yogurt while remaining durable even after being submerged in ketchup for over one month. This work was supported by Bemis North America (AT-23981).

Investigation of effect of electron beam on various polyethylene blends

International Nuclear Information System (INIS)

Morshedian, J.; Pourrashidi, A.

2003-01-01

With regards to the expanding usage of electron beams irradiation in polymer industries such as sterilization of polymeric disposable medical products; cable manufacturing; pipes, heat shrinkable materials, etc. In this project the effect of electron beam on polyethylene used in manufacturing of pipe and heat shrinkable products was studied. Results showed that by increasing the applied dose on samples; the crosslink density would increase and polymers with tertiary carbon atoms in their backbone structure tend to crosslink more readily. The melting temperature and crystallinity percent decreased and degradation temperature increased. Density in low doses decreased and in high doses increased

Investigation of effect of electron beam on various polyethylene blends

CERN Document Server

Morshedian, J

2003-01-01

With regards to the expanding usage of electron beams irradiation in polymer industries such as sterilization of polymeric disposable medical products; cable manufacturing; pipes, heat shrinkable materials, etc. In this project the effect of electron beam on polyethylene used in manufacturing of pipe and heat shrinkable products was studied. Results showed that by increasing the applied dose on samples; the crosslink density would increase and polymers with tertiary carbon atoms in their backbone structure tend to crosslink more readily. The melting temperature and crystallinity percent decreased and degradation temperature increased. Density in low doses decreased and in high doses increased.

Changes in total carbohydrate and total antioxidant activity induced by gamma irradiation of wheat flour

International Nuclear Information System (INIS)

Manupriya, B.R.; Shenoy, K. Bhasker; Patil, Shrikant L.; Somashekarappa, H.M.

2015-01-01

Wheat is a staple food grain in India after rice and occupies number one position in the world. The wheat crop not only gives food grains but also gives fodder for animals. Among many preservation methods irradiation is a current technique used to overcome infestation, contamination and spoilage of stored grains. The present study is aimed to check the changes in composition of irradiated wheat flour. Wheat flour was exposed to five different irradiation doses (0.25 KGy, 0.5KGy, 1KGy, 5KGy and 10 KGy) by using 60 Co gamma-irradiation chamber. Irradiated flour was stored in air sealed polyethylene pouch and plastic container at room temperature for different time intervals (0 th day, 1 month and 3 months). The stored flour was checked for total antioxidant activity by phosphomolybdate method and total carbohydrates concentration by phenol-sulphuric acid method. On 0 th day total antioxidant activity and total carbohydrate concentration was found to be increased at 0.5KGy (0.113 mg/ml and 0.045 mg/ml respectively) when compared to control (0.79 mg/ml and 39.5 mg/ml). Similarly for 1 month stored samples of air sealed polyethylene pouch total antioxidant activity and total carbohydrate concentration was observed to be increased at 0.5KGy (0.117 mg/ml and 0.045mg/ml respectively) when compared to control (0.096 mg/ml and 0.035 mg/ml). But in case of stored samples of plastic container total antioxidant activity increased at 0.25KGy (0.060 mg/ml) and total carbohydrate increased at 5KGy (0.051 mg/ml). Increased and decreased values were found in both factors for 3 months stored samples of air sealed polyethylene pouch and plastic container. Total antioxidant activity increased at 5KGy (0.072 mg/ml) for polyethylene bag samples and at 0.5KGy (0.137 mg/ml) for plastic container sample. Same way total carbohydrate concentration increased at 0.25KGy (0.046 mg/ml) and at 1KGy (0.045 mg/ml) respectively. This increase is due to affects of γ-irradiation on biomolecules by

Effect of the addition of lithium carbonate on the properties of low density polyethylene

International Nuclear Information System (INIS)

Hoshimura, Yoshikazu; Yamamoto, Shigeru

1992-01-01

For improvement of the properties of polyethylene (PE), γ-ray was irradiated to the lithium carbonate added PE. An increase in the numbers of OH and C=C bonds was observed from FT-IR measurements. The melting temperature (or the vanishing temperature of crystallinity by X-ray diffraction) of the lithium carbonate added PE after γ-ray irradiation (10 6 Gy) was 20degC higher than that of the PE's with no additives and with quartz added PE. The lamellae of lithium carbonate added PE were not observed in the scanning electron micrographs. This vanishing of lamellae of the lithium carbonate added PE was also suggested by the extinction of the maltese cross with a polarizing microscope. (author)

Techno-economic feasibility of food irradiation in Ghana

International Nuclear Information System (INIS)

Appiah, V.; Nketsia-Tabiri, J.; Bansa, D.; Montford, K.G.; Sakyi Dawson, E.; Alhassan, R.; Edwards, J.

2002-01-01

The major causes of spoilage in the post-harvest handling of yam were identified as poor harvest, storage and transportation conditions and physiological damage. The effect of gamma irradiation on yam and maize storage and their functionality in the Ghanaian food system were determined. Results indicated that all unirradiated yams sprouted by the 3rd month of storage. Gamma irradiation at a dose of 120-130 Gy effectively inhibited sprouting of yams for 6 months under ambient conditions. There was less rotting in yams stored on the barn compared to those stored on the ground and less rotting in the irradiated yam stored on the barn. Food products from irradiated yams were judged better in quality than those from unirradiated ones. Semi-commercial studies on radiation preservation of maize were conducted with the view to determining the effect of radiation treatment on the physico-chemical and functional properties as well as the microbiological quality of maize. The study also investigated techno-economic feasibility of radiation preservation of maize in Ghana and consumer attitudes towards foods such as 'Ga kenkey' and 'Fanti kenkey' prepared from irradiated maize. In the first study 127 bags of 50kg maize were used. Maize was repacked in 5-kg consumer packs made from 0.003mm thick polyethylene bags. Ten of the consumer packs were put into woven polypropylene sacks to make up 50kg bag of maize. Eighty-seven bags of maize were irradiated to a minimum of 2.6 and maximum of 5.6 kGy gamma radiation. Both the irradiated and the unirradiated maize were stored for six months in a commercial warehouse. Results indicated that the moisture content (7.2-7.8%), free fatty acid (<0.1%) and peroxide value (35-40 mEq/kg fat) of the maize were stable during storage. The initial mould count of 100-156 cfu/g decreased to 30-43 cfu/g; Aspergillus oryzae and Asp. tamari were identified. Sitophilus sp. was the predominant insect in the control but was replaced by Rhyzopertha sp. in the

Techno-economic feasibility of food irradiation in Ghana

Energy Technology Data Exchange (ETDEWEB)

Appiah, V; Nketsia-Tabiri, J; Bansa, D; Montford, K G [Department of Food Science and Radiation Processing, Biotechnology and Nuclear Agriculture Research Institute (Ghana); Sakyi Dawson, E [Department of Food Science and Nutrition, University of Ghana (Ghana); Alhassan, R [Department of Agriculture Economics, Faculty of Agriculture, University of Ghana (Ghana); Edwards, J [Ghana Food Distribution Corporation (Ghana)

2002-05-01

The major causes of spoilage in the post-harvest handling of yam were identified as poor harvest, storage and transportation conditions and physiological damage. The effect of gamma irradiation on yam and maize storage and their functionality in the Ghanaian food system were determined. Results indicated that all unirradiated yams sprouted by the 3rd month of storage. Gamma irradiation at a dose of 120-130 Gy effectively inhibited sprouting of yams for 6 months under ambient conditions. There was less rotting in yams stored on the barn compared to those stored on the ground and less rotting in the irradiated yam stored on the barn. Food products from irradiated yams were judged better in quality than those from unirradiated ones. Semi-commercial studies on radiation preservation of maize were conducted with the view to determining the effect of radiation treatment on the physico-chemical and functional properties as well as the microbiological quality of maize. The study also investigated techno-economic feasibility of radiation preservation of maize in Ghana and consumer attitudes towards foods such as 'Ga kenkey' and 'Fanti kenkey' prepared from irradiated maize. In the first study 127 bags of 50kg maize were used. Maize was repacked in 5-kg consumer packs made from 0.003mm thick polyethylene bags. Ten of the consumer packs were put into woven polypropylene sacks to make up 50kg bag of maize. Eighty-seven bags of maize were irradiated to a minimum of 2.6 and maximum of 5.6 kGy gamma radiation. Both the irradiated and the unirradiated maize were stored for six months in a commercial warehouse. Results indicated that the moisture content (7.2-7.8%), free fatty acid (<0.1%) and peroxide value (35-40 mEq/kg fat) of the maize were stable during storage. The initial mould count of 100-156 cfu/g decreased to 30-43 cfu/g; Aspergillus oryzae and Asp. tamari were identified. Sitophilus sp. was the predominant insect in the control but was replaced by Rhyzopertha sp. in the

Insect disinfestation of pulses by irradiation

International Nuclear Information System (INIS)

Bhuiya, A.D.; Ahmed, M.; Rezaur, R.; Seal, D.R.; Nahar, G.; Islam, M.M.; Islam, M.S.

1985-01-01

Studies were carried out on four varieties of pulses, namely, mosur or lentil (Lens esculenta), mung (Phaseolus aureus), chola or gram (Cirecer aricitinum), and mashkalai (Phaseolus radiatus). Two major burchid betles, Callosobruchus chinensis (L.) and Callosobruchus analis (Fab.), were found to infest different varieties of pulses. Radiation sensitivity of the two pulse beetles was determined at different developmental stages (i.e., eggs, larvae, and pupae). Emergence of adults from eggs totally stopped at a dose of 0.04 kGy. Doses of 0.28 and 0.32 kGy, respectively, were required for complete inhibition of adult emergence from irradiated fourth instar larvae of C. analis and C. chinensis. Studies revealed that the experimental gram was heavily infested (65-91 percent) as compared to other pulses after 8 months of storage in all packaging materials used (gunny bag, gunny bag lined with polyethylene, polyethylene and polyvinyl chloride bags). Mashkalai showed insignificant damage (2-5 percent) by the insects. Reinfestation in the treated products was observed in polyethylene and gunny bags

Absorbed Dose Distributions in Irradiated Plastic Tubing and Wire Insulation

DEFF Research Database (Denmark)

Miller, Arne; McLaughlin, W. L.

1979-01-01

Plastic tubing and wire insulation were simulated by radiochromic dye dosimeter films having electron absorbing properties similar to the materials of interest (polyethylene and PVC). A 400-keV electron accelerator was used to irradiate from 1, 2, 3 and 4 sides simulating possible industrial...

Biliary and pancreatic secretions in abdominal irradiation

International Nuclear Information System (INIS)

Becciolini, A.; Cionini, L.; Cappellini, M.; Atzeni, G.

1979-01-01

The biliary and pancreatic secretions have been determined in patients given pelvic or para-aortic irradiation, with a dose of 50 Gy in the former group and between 36 and 40 Gy in the latter. A test meal containing polyethylene glycol (PEG) as reference substance was used. Each sample of the duodenal content was assayed for volume, PEG content, amylase and trypsin activity, pH and biliary secretion. No significant modifications of biliary and pancreatic secretions were demonstrated after irradiation, suggesting that these functions are not involved in the pathogenesis of the malabsorption radiation syndrome. (Auth.)

Polyethylene (PE) based proton exchange membrane for use in fuel cell

International Nuclear Information System (INIS)

Moraes, Gilberto de Oliveira

2008-01-01

The irradiation - induced graft of styrene onto polyethylene (PE) in a Cobalt-60 source was carried out using direct (simultaneous) and indirect (preirradiation and peroxidation) methods at room temperature. The dose applied in both cases varied from 0,5 to 80 kGy; In the direct method, the films were immersed in a solution of styrene: methanol (30:70 v/v) and 30% of sulfuric acid(additive) in glass ampoules of 40 ml under inert atmosphere, and then irradiated. After irradiation process, the samples were kept in solution for 8 hours and taken off the ampoules, dried in oven at 60 deg C for another 8 hour period until constant weight. In pre-irradiation method, the samples were irradiated in dry and sealed ampoules, under inert atmosphere. The solution was then added to the samples, and after 8 hours, taken off, dried, sealed and weighted. In peroxidation method, the difference was not inert atmosphere but atmosphere of air (0 2 ).For each samples it was calculated the degree of grafting (DOG). The samples that showed some DOG were sulfonated, characterized (DSC, TGA and infrared) and the ion exchange capacity (IEC) was calculated. The samples processed by indirect method presented no DOG at all. The samples processed by direct method present grafting (best result was 80 kGy). These samples, after sulfonated, presented ion exchange properties. (author)

Seed germination of peanuts irradiated with cobalt (60CO)

International Nuclear Information System (INIS)

Alves, Niedja Marrize C.; Almeida, Francisco de Assis C.; Gomes, Josivanda P.; Pessoa, Elvira B.; Leal, Artur S. Cavalcanti

2010-01-01

This work was realized to evaluate the effect of gamma irradiation ( 60 Co) at doses 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 and 4.00 kGy, on germination of seeds of peanut, cultivar BR1. Irradiation Department of Nuclear, UFPE, where he received after the irradiation, they were stored in packing of PET and polyethylene braided with a time of 90 days. Through the results, obtained monthly, concluded that the dose of 0.5 kGy was effective in the germination of seeds of peanut, not affecting its power of germination and overcoming the witness within 30 to 60 days. (author)

Interspecific transfer of only part of genome by fusion between non-irradiated protoplasts of Nicotiana glauca and X-ray irradiated protoplasts of N. Langsdorffii

International Nuclear Information System (INIS)

Itoh, K.; Futsuhara, Y.

1983-01-01

To transfer only part of genome, X-ray irradiated suspension cell protoplasts of N. langsdorffii were fused with suspension cell protoplasts of N. glauca by polyethylene glycol. Somatic hybrid calli were selected by the growth in the hormone-free medium. Some of somatic hybrid calli from fusion with irradiated protoplasts indicated the loss of small subunit polypeptide of fraction 1 protein which was coded by N. langsdorffii nuclear DNA. Cytological analysis provided an information on significant decrease of chromosomes in somatic hybrid calli from fusion with irradiated protoplasts, compared with the somatic hybrid calli from fusion with non-irradiated protoplasts. In addition, isozyme analysis revealed that somatic hybrid calli from fusion with irradiated protoplasts lost particular bands of N. langsdorffli. These results demonstrate the tranfer of only part of genome from N, langsdorffii to N, glauca by fusion with X-ray irradiated protoplasts

A study on UV irradiated HDPE

International Nuclear Information System (INIS)

Sang Haibo; Liu Zimin; Wu Shishan; Shen Jian

2006-01-01

The structure and properties of HDPE irradiated by ultraviolet (UV) in ozone atmosphere were studied by FT-IR, XPS, gel, and water contact angle test. The oxygen-containing groups such as C=O, C-O and C(=O)O were introduced onto high density polyethylene (HDPE) chains through ultraviolet irradiation in ozone atmosphere, their content increased with the UV irradiation time. Under the same UV irradiation conditions, amount of the oxygen-containing groups introduced in ozone atmosphere was more than that in air atmosphere, indicating that the speed of oxygen-containing groups introduced through UV irradiation in ozone atmosphere was faster than that in air. Therefore, HDPE could be quickly functionalized through UV irradiation in ozone atmosphere. There was no gel formed in the HDPE irradiated in ozone atmosphere. After UV irradiation, the water contact angle of HDPE decreased, and its hydrophilicity was improved, suggesting that the compatibility between the irradiated HDPE and polar polymer or inorganic fillers may be better. Compared with HDPE, the temperature of initial weight loss for irradiated HDPE decreased. The structure and properties of irradiated HDPE/CaCO 3 blend were also investigated. The results showed that the compatibility and interfacial action of the irradiated HDPE/CaCO 3 blend were improved compared to that of HDPE/CaCO 3 blend. The mechanical properties of irradiated HDPE/CaCO 3 blend increased with increasing irradiation time. (authors)

Polyethylene as a possible hvdc cable insulant

Energy Technology Data Exchange (ETDEWEB)

Hawley, W.G.; Body, R.S.; Mason, J.H.

1966-10-01

Many cable authorities have expressed the view that polyethylene would be attractive for this application. The dc conductivity of polyethylene is lower than that of impregnated paper, and varies less with temperature and stress. Polyethylene also has higher thermal conductivity and is resistant to moisture and electrochemical deterioration. Furthermore, processing polyethylene cables should ultimately involve lower capital and manufacturing costs. However, polyethylene has a lower limiting short circuit temperature unless it is cross linked.

High gamma dose response of the electrical properties of polyethylene terephthalate thin films

International Nuclear Information System (INIS)

Radwan, R.M.

2007-01-01

Electrical properties of polyethylene terephthalate (PET), irradiated with gamma rays, have been investigated. The PET films were irradiated with high gamma dose levels in the range from 100 to 2000 kGy. The changes in the DC (σ DC ) and the ac (σ ac ) conductivities, with the dose, have been performed. The effect of gamma irradiation on the dielectric constant (ε') and loss (ε'') has been determined. Also, the dose dependence of the frequency exponent index (S), the resonance frequency (Fc) and the hopping frequency (ω P ) have been obtained. The obtained results show that increasing gamma dose leads to slight increase in σ DC , σ ac and ε', while no change was observed in ε'' value. Meanwhile, S, Fc and ω P are inversely proportional to the dose. Accordingly, the study suggests the possibility of using PET films in electronic components (capacitors, resistors, etc.), especially that operate at high gamma dose environments for the frequency independent applications

Effect of packaging films on the microflora of gamma irradiated vienna sausages

International Nuclear Information System (INIS)

Ito, Hitoshi; Watanabe, Hiroshi; Aoki, Shohei; Sato, Tomotaro

1977-01-01

Slime production of radurized VS (vienna sausage) was prevented largely in a package of O 2 gas unpermeable films such as K-cellophane and EG-Q more than cellophane-polyethylene film when packed with N 2 gas and stored at 10 0 C, 90% r.h. All of the total microbial count in non-irradiated VS packed in every film reached 1 x 10 6 per gram after 2 to 3 days storage, and slime production was observed at this level. In the case of radurized VS, the total count reached 1 x 10 6 per gram after 4 to 5 days at 300 krad and after 7 to 8 days at 500 krad in cellophane-polyethylene, while it prolonged for 7 to 9 days at 300 krad and for more than 13 or 15 days at 500 krad in K-cellophane or EG-Q. The main microorganisms occurring in non-irradiated VS packed with N 2 or CO 2 gas in K-cellophane or EG-Q were lactic acid bacteria, and the growth of other organisms such as MA (an Intermediate type of Moraxella-Acinetobacter), yeasts and Micrococcus was suppressed under these conditions. The growth of surviving organisms consisting of MA and yeasts in radurized VS was also suppressed. A small amount of off-flavor detected after irradiation at 500 krad disappeared in cellophane-polyethylene after 7 days storage. But it remained in the O 2 gas unpermeable films. (auth.)

utilization of some physical methods for detection of some irradiated foods

International Nuclear Information System (INIS)

Mohammed, I.A.S

2007-01-01

the present investigation was carried out to establish a detection method for irradiated black pepper and marjoram using thermoluminescence (TL) and wheat, cinnamon and ginger using viscosity measurement. all samples were packed in polyethylene bags then irradiated at 5,10 and 15 kGy for black pepper, marjoram, cinnamon and ginger. wheat was irradiated at 1,2 and 3 kGy. all samples were stored for eight months at room temperature. results indicated that irradiation treatment caused markedly increasing in TL intensity for irradiated black pepper and marjoram while irradiation treatment decreased apparent viscosity of wheat flour, cinnamon and ginger powder, post irradiation and during storage. therefore, it could be concluded that the TL analysis can be used to detect irradiated black pepper and marjoram, also viscosity measurement can be used to detect irradiate wheat flour, cinnamon and ginger powder than non-irradiated ones after irradiation process and also during 8 months of storage at ambient temperature

Analysis of Hydroperoxides in solid Polyethylene by NMR and EPR Spectroscopy

International Nuclear Information System (INIS)

Assink, Roger A.; Celina, Mathias C.; Dunbar, Timothy D.; Alam, Todd M.; Clough, Roger Lee; Gillen, Kenneth T.

2000-01-01

The authors have shown that the hydroperoxide species in γ-irradiated 13 C-polyethylene can be directly observed by 13 C MAS NMR spectroscopy. The experiment was performed without the need for special sample preparation such as chemical derivatization or dissolution. Annealing experiments were employed to study the thermal decomposition of the hydroperoxide species and to measure an activation energy of 98 kJ/mol. EPR spectroscopy suggests that residual polyenyl and alkylperoxy radicals are predominantly trapped in interracial or crystalline regions, while the peroxy radicals observed after UV-photolysis of hydroperoxides are in amorphous regions

Synthesis of ion exchange membrane by radiation grafting of acrylic acid onto polyethylene

International Nuclear Information System (INIS)

Ishigaki, I.; Sugo, T.; Senoo, K.; Takayama, T.; Machi, S.; Okamoto, J.; Okada, T.

1981-01-01

Radiation grafting of vinyl monomers onto polymer films has been extensively studied by many workers. In the preirradiation method of grafting a polymer substrate is activated by irradiation (either in the presence or absence of oxygen) and subsequently allowed to react with a monomer. The preirradiation method was utilized in this study to synthesize an ion exchange membrane useful for a battery separator by grafting acrylic acid onto polyethylene film. The battery separator should be chemically and thermally stable, sufficiently durable in electrolyte as well as highly electrically conductive. Membranes made from regenerated cellulose, e.g., cellophane, have long been used as a separator in the batteries with alkaline electrolyte, such as silver oxide primary cell. However, it has poor durability, as short as one year, due to breakdown of the membrane during operation or storing. The acrylic acid-grafted polyethylene film was found to be quite useful for a separator in the alkaline batteries. This membrane has a high electric conductivity and an excellent durability. (author)

Preparation of the copolymer of acrylic acid and acrylamide grafted onto polyethylene and its complexation with samarium ion

International Nuclear Information System (INIS)

Kido, Junji; Akiba, Hideto; Nishide, Hiroyuki; Tsuchida, Eishun; Omichi, Hideki; Okamoto, Jiro.

1986-01-01

Acrylic acid (AA) and acrylamide (AAm) were graft-copolymerized onto polyethylene (PE) powder by the pre-irradiation method. Complex formation constants of Sm ion with the PE powder grafted with both AA and AAm (PE-g-(AA-co-AAm)) were larger than those with the PE powder grafted with AA (PE-g-AA). Sm ion was efficiently separated from the solution containing both Sm ion and a transition metal ion such as Cu ion. Even after the γ-ray irradiation on PE-g-(AA-co-AAm) and PE-g-AA, the adsorption did not decrease. (author)

The evaluation of nylon and polyethylene as build-up material in a neutron therapy beam

International Nuclear Information System (INIS)

Hough, J.H.; Binns, P.J.

1995-01-01

In high-energy neutron beams a substantial amount of build-up material is required to irradiate biological samples under conditions of charged particle equilibrium. Ideally A-150 tissue-equivalent plastic is used for this purpose. This material is however not always readily available and hence the need for a substitute compound. The selected hydrocarbon should satisfy two requirements: the quality of the radiation on the distal side needs to be the same as that measured for A-150 plastic and the absorbed dose should remain consistent. A tissue-equivalent proportional counter operating at reduced pressure not only measures the absorbed dose accurately but provides a means for assessing the nature of a radiation field in terms of a secondary charged particle spectrum. Using build-up caps manufactured from nylon (type 6) and polyethylene, it is shown that the former is an acceptable substitute for A-150 plastic. The data further demonstrate that both the absorbed dose and the spectral character of the measured single-event distribution are altered when polyethylene is used and that these discrepancies are attributable to the higher hydrogen content of polyethylene. (Author)

Some radiation aspects of irradiated polyethylene and polypropylene

International Nuclear Information System (INIS)

Gvozdic, N.V.

1978-01-01

Unfractionated PE (Marlex-6002, ECPE, HPE) and fractionated PE (MWD approximately 3.7) were used for the study of ionizing radiation effects such as vinyl decay in relation to the degree of crystallinity, as well as crosslinking, G(alkyl), and free radical decay. Isotactic PP was used for the study of alkyl radical decay. It was found that the rate of vinyl decay in PE is dependent on the degree of crystallinity only if free radicals were not annealed out subsequent to irradiation and before measurements. Both annealed and quenched samples have shown the same rate of vinyl decay if free radicals were annealed out. The study of crosslink formation in relation to the degree of crystallinity has disclosed that the higher gel fraction is always obtained in the highly amorphous samples, rather than in the highly crystalline ones. The study of G(alkyl) for irradiated PE, has disclosed that a higher G(alkyl) value is in the amorphous than in the crystalline regions. This result indirectly supports the conclusion that gel is formed preferably in the quenched than in the annealed samples. The higher G(alkyl) in i-PP than in PE was expected on the basis of the more effective Frank-Rabinowitch caging effect in PE. Evidence has been obtained for the production of two kinds of alkyl radicals in i-PP at LNT. That is, alkyl radical species of 4- and 8-line ESR spectra. A new transformation temperature of alkyl radical spectra (approximately 313 0 K) was discovered. The study of decay of alkyl radical (8-line) species has revealed that neither simple first nor second order rate laws were obeyed, above or below Tg. The H 2 catalytic effect on alkyl (8-line) species was discovered at the temperature above Tg but not below Tg

Effect of gamma irradiation on total carbohydrate concentration of finger millet flour

International Nuclear Information System (INIS)

Lathika; Patil, Shrikant L.; Bhasker Shenoy, K.; Somashekarappa, H.M.

2015-01-01

Ragi or finger millet (Eleusine coracana L.) is one of the common millets in several regions of India. The effect of gamma irradiation, on ragi flour was investigated in the study. Ragi flour is procured from market. Flour samples of 50 gms were taken in triplicates in a polyethylene pouch, air sealed and subjected to gamma irradiation doses ranging from 0.25 to 10 kGy and stored in polyethylene bags and plastic containers for a period of 30 and 90 days. Within 24 hours of irradiation, the samples were tested for total carbohydrate concentration by phenol-sulphuric acid method. The same was repeated after 30 and 90 days of storage. The comparative study showed that, at 0 day, total carbohydrate concentration has decreased slightly when compared to the non-irradiated sample (0.024 mg/ml). The lowest concentration of carbohydrate is seen at 0.025 kGy (0.019mg/ml). The samples stored in polyethylene bag, after 30 days showed both increase (0.056 mg/ml at 0.025 kGy) and decrease (0.04 mg/ml at 10 kGy) in total carbohydrate concentration when compared to control (0.046 mg/ml). 90 days stored samples showed increase in carbohydrate concentration when compared to control (0.029 mg/ml). The highest carbohydrate concentration is seen in 1 kGy dose (0.037 mg/ml). The samples stored at container after 30 days showed both increase (0.045 mg/ml at 5 kGy) and decrease (0.034 mg/ml at 0.025 mg/ml) of carbohydrate concentration when compared to control (0.043 mg/ml). 90 days stored samples showed decrease in carbohydrate concentration when compared to control (0.034 mg/ml). The lowest concentration is seen at 5 kGy (0.022 mg/ml). (author)

Effect of gamma irradiation in sterilization of dry dextran as plasma substitute and sodium chloride

Energy Technology Data Exchange (ETDEWEB)

Piatkiewicz, A; Kusewicz, D [Politechnika Lodzka (Poland)

1975-01-01

The exposure of dry dextran, sodium chloride and polyethylene packing to 0,3-2 Mrad of gamma irradiation decreased their contamination by 60 to 96%. The sterilization effect of irradiation increased with gamma-ray dose. Spores of Bacillus subtilis and Aspergillus niger were shown to be the most resistant to gamma-ray treatment. In some samples the resistant Micrococcus was also detected.

Preparation of various hydrogels based on poly (Vinyl pyrrolidone) and poly ethylene glycol using gamma and electron irradiation

International Nuclear Information System (INIS)

Ajji, Z.

2006-11-01

Different hydrogels have been prepared using gamma and electron irradiation; the hydrogels are composed of poly(vinyl pyrolidone) (PVP), poly(ethylene glycol) (PEG). The influence of some process parameters on the properties of the hydrogels has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. In the first part of this study, hydrogel dressings have been prepared using electron irradiation, and the dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The gel fraction increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. The prepared hydrogels dressings could be considered as a good barrier against microbes. In the second part, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. In the third part of the study, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and poly(ethylene glycol) (PEG) with various molecular weights, and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. The data show that PEG with low molecular weight needs a high dose for the gelation, and the presence of PVP lowers the needed gelation dose. The maximum swelling decreases with increasing irradiation dose and the PVP concentration, which is due to higher crosslinks between the polymer chains. (author)

Radiation-Induced Grafting with One-Step Process of Waste Polyurethane onto High-Density Polyethylene

Directory of Open Access Journals (Sweden)

Jong-Seok Park

2015-12-01

Full Text Available The recycling of waste polyurethane (PU using radiation-induced grafting was investigated. The grafting of waste PU onto a high-density polyethylene (HDPE matrix was carried out using a radiation technique with maleic anhydride (MAH. HDPE pellets and PU powders were immersed in a MAH-acetone solution. Finally, the prepared mixtures were irradiated with an electron beam accelerator. The grafted composites were characterized by Fourier transformed infrared spectroscopy (FT-IR, surface morphology, and mechanical properties. To make a good composite, the improvement in compatibility between HDPE and PU is an important factor. Radiation-induced grafting increased interfacial adhesion between the PU domain and the HDPE matrix. When the absorbed dose was 75 kGy, the surface morphology of the irradiated PU/HDPE composite was nearly a smooth and single phase, and the elongation at break increased by approximately three times compared with that of non-irradiated PU/HDPE composite.

Irradiation versus methyl bromide fumigation or heating as procedures for increasing shelf life of dry date varieties

International Nuclear Information System (INIS)

El-Samahy, S.K.; Abd El-Hady, S.A.; Swailam, H.M.

2004-01-01

The objective of this study is to evaluate the use of irradiation as an alternative method and comparing it with the traditional methods such as fumigation and heating for increasing shelf life dry date varieties. two varieties of dry dates, Malakaby and Gandilla, were obtained from Aswan, Upper Egypt and were used in this study. The irradiation was carried out with different doses of gamma rays to select the recommended dose to increase shelf life of dry dates. The fumigated, heated and irradiated samples were stored at room temperature after packaging in polyethylene plus cloth bags. The date characteristics such as insect infestation percent, weight loss, microbiological analyses, and firmness and chemical analyses were evaluated. The results obtained indicated that irradiation as a procedure for insect disinfestation and increasing shelf life of dry dates was better than both fumigation and heating methods. Where, irradiation of date fruits at dose of 1.0 kGy inhibited the insect infestation and improved the microbial quality of the date fruits during storage up to 18 months. Adding cloths to polyethylene packages raised the percentage of intact dry date fruits

Solid-phase photocatalytic degradation of polystyrene plastic with goethite modified by boron under UV-vis light irradiation

International Nuclear Information System (INIS)

Liu Guanglong; Zhu Duanwei; Zhou Wenbing; Liao Shuijiao; Cui Jingzhen; Wu Kang; Hamilton, David

2010-01-01

A novel photodegradable polyethylene-boron-goethite (PE-B-goethite) composite film was prepared by embedding the boron-doped goethite into the commercial polyethylene. The goethite catalyst was modified by boron in order to improve its photocatalytic efficiency under the ultraviolet and visible light irradiation. Solid-phase photocatalytic degradation of the PE-B-goethite composite film was carried out in an ambient air at room temperature under ultraviolet and visible light irradiation. The properties of composite films were compared with those of the pure PE films and the PE-goethite composite films through performing weight loss monitoring, scanning electron microscope (SEM) analysis, FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). The photo-induced degradation of PE-B-goethite composite films was higher than that of the pure PE films and the PE-goethite composite films under the UV-irradiation, while there has been little change under the visible light irradiation. The weight loss of the PE-B-goethite (0.4 wt.%) composite film reached 12.6% under the UV-irradiation for 300 h. The photocatalytic degradation mechanism of the composite films was briefly discussed.

Method and equipment to lead a cable-like material under an irradiation source

International Nuclear Information System (INIS)

Riesselmann, F.J.

1975-01-01

When irradiating cable-like material (cable jacketed with polyethylene) which is led through an irradiation source and is thus turned and twisted, no uniform irradiation and twist changes have so far been obtained. It is suggested to twist the cable before the first circuit by about 45 0 in one direction, after turning and the second circuit, to twist by about 90 0 in the other direction and to follow with a further two circuits with twisting. A suitable cable twisting device which works with discrete clamping jaw is described in detail. (UWI) [de

Properties of Polyethylene Naphthalate Track Membranes

CERN Document Server

Akimenko, S N; Orelovich, O L; Maekawa, J; Ioshida, M; Apel, P Yu

2002-01-01

Basic characteristics of track membranes made of polyethylene naphthalate (which is a polyester synthesized from dimethyl naphthalate and ethylene glycol) are studied and presented. Polyethylene naphthalate possesses some properties (mechanical strength, thermal and chemical stability), which make this polymer a promising material for the production of track membranes. Water flow rate and air flow rate characteristics, burst strength, wettability, and amount of extractables are determined. Surface structure and pore structure are examined using scanning electron microscopy. It is found that the pores in the membranes are cylindrical in shape. The measured water and air flow rates follow known theoretical relations for the transport in narrow capillaries. The burst strength of polyethylene naphthalate membranes is found to be similar to that of polyethylene terephthalate track membranes. Polyethylene naphthalate track membranes can be categorized as moderately hydrophilic. Being treated with boiling water, pol...

Effect of packaging films on the microflora of gamma irradiated vienna sausages

Energy Technology Data Exchange (ETDEWEB)

Ito, H; Watanabe, H; Aoki, S; Sato, T [Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment

1977-10-01

Slime production in radurized VS (vienna sausage) was prevented to a greater extent when packaged in O/sub 2/- impermeable films such as K-cellophane and EG-Q than in cellophane-polyethylene film when packed with N/sub 2/ gas and stored at 10/sup 0/C, 90% r.h. The total microbial count in non-irradiated VS packed in every film reached 1 x 10/sup 6/ per gram after 2 to 3 days storage, and slime production was observed at this level. In the case of radurized VS, the total count reached 1 x 10/sup 6/ per gram after 4 to 5 days at 300 krad and after 7 to 8 days at 500 krad in cellophane-polyethylene, while it was prolonged for 7 to 9 days at 300 krad and for more than 13 to 15 days at 500 krad in K-cellophane or EG-Q. The main microorganisms occurring in non-irradiated VS packed with N/sub 2/ or CO/sub 2/ gas in K-cellophane or EG-Q were lactic acid bacteria, and the growth of other organisms such as MA (an intermediate type of Moraxella-Acinetobacter), yeasts, and Micrococcus was suppressed under these conditions. The growth of surviving organisms consisting of MA and yeasts in radurized VS was also suppressed. A small amount of off-flavor detected after irradiation at 500 krad disappeared in cellophane-polyethylene after 7 days storage, but it remained in the O/sub 2/ gas impermeable films.

Ultralow energy ion beam surface modification of low density polyethylene.

Science.gov (United States)

Shenton, Martyn J; Bradley, James W; van den Berg, Jaap A; Armour, David G; Stevens, Gary C

2005-12-01

Ultralow energy Ar+ and O+ ion beam irradiation of low density polyethylene has been carried out under controlled dose and monoenergetic conditions. XPS of Ar+-treated surfaces exposed to ambient atmosphere show that the bombardment of 50 eV Ar+ ions at a total dose of 10(16) cm(-2) gives rise to very reactive surfaces with oxygen incorporation at about 50% of the species present in the upper surface layer. Using pure O+ beam irradiation, comparatively low O incorporation is achieved without exposure to atmosphere (approximately 13% O in the upper surface). However, if the surface is activated by Ar+ pretreatment, then large oxygen contents can be achieved under subsequent O+ irradiation (up to 48% O). The results show that for very low energy (20 eV) oxygen ions there is a dose threshold of about 5 x 10(15) cm(-2) before surface oxygen incorporation is observed. It appears that, for both Ar+ and O+ ions in this regime, the degree of surface modification is only very weakly dependent on the ion energy. The results suggest that in the nonequilibrium plasma treatment of polymers, where the ion flux is typically 10(18) m(-2) s(-1), low energy ions (<50 eV) may be responsible for surface chemical modification.

Characterization of the neutron irradiation system for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories.

Energy Technology Data Exchange (ETDEWEB)

Franco, Manuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-08-01

The objective of this work was to characterize the neutron irradiation system consisting of americium-241 beryllium (241AmBe) neutron sources placed in a polyethylene shielding for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three recycled 241AmBe sources of different activities that had been combined into a single source. The source in its polyethylene shielding will be used in neutron irradiation testing of components. The characterization of the source-shielding system was necessary to evaluate the radiation environment for future experiments. Characterization of the source was also necessary because the documentation for the three component sources and their relative alignment within the Special Form Capsule (SFC) was inadequate. The system consisting of the source and shielding was modeled using Monte Carlo N-Particle transport code (MCNP). The model was validated by benchmarking it against measurements using multiple techniques. To characterize the radiation fields over the full spatial geometry of the irradiation system, it was necessary to use a number of instruments of varying sensitivities. First, the computed photon radiography assisted in determining orientation of the component sources. With the capsule properly oriented inside the shielding, the neutron spectra were measured using a variety of techniques. A N-probe Microspec and a neutron Bubble Dosimeter Spectrometer (BDS) set were used to characterize the neutron spectra/field in several locations. In the third technique, neutron foil activation was used to ascertain the neutron spectra. A high purity germanium (HPGe) detector was used to characterize the photon spectrum. The experimentally measured spectra and the MCNP results compared well. Once the MCNP model was validated to an adequate level of confidence, parametric analyses was performed on the model to optimize for potential

Irradiated ground beef: sensory and quality changes during storage under various packaging conditions

International Nuclear Information System (INIS)

Murano, P.S.; Murano, E.A.; Olson, D.G.

1998-01-01

Ground beef patties (irradiated with 2 kGy and nonirradiated) were packaged using oxygen permeable (polyolefin) or oxygen impermeable material (polyethylene). Samples were irradiated in air and stored in air; irradiated under vacuum and stored under vacuum; or irradiated under vacuum and stored in air. Changes in flavor, texture, juiciness or aftertaste were evaluated after either 1 or 7 days storage at -25 degrees C prior to cooking. Irradiated 'Vac/Air' samples were more tender, irradiated 'Vac' samples were more moist, and irradiated 'Air' samples had the least aftertaste. A 3 log10 reduction in total aerobic counts was detected immediately after irradiation. No difference in lipid oxidation was found within the first week of storage, regardless of packaging atmosphere. Shelf life of ground beef patties was extended 55 days at 4 degrees C

Physicochemical modifications accompanying UV laser induced surface structures on poly(ethylene terephthalate) and their effect on adhesion of mesenchymal cells.

Science.gov (United States)

Rebollar, Esther; Pérez, Susana; Hernández, Margarita; Domingo, Concepción; Martín, Margarita; Ezquerra, Tiberio A; García-Ruiz, Josefa P; Castillejo, Marta

2014-09-07

This work reports on the formation of different types of structures on the surface of polymer films upon UV laser irradiation. Poly(ethylene terephthalate) was irradiated with nanosecond UV pulses at 193 and 266 nm. The polarization of the laser beam and the irradiation angle of incidence were varied, giving rise to laser induced surface structures with different shapes and periodicities. The irradiated surfaces were topographically characterized by atomic force microscopy and the chemical modifications induced by laser irradiation were inspected via micro-Raman and fluorescence spectroscopies. Contact angle measurements were performed with different liquids, and the results evaluated in terms of surface free energy components. Finally, in order to test the influence of surface properties for a potential application, the modified surfaces were used for mesenchymal stem cell culture assays and the effect of nanostructure and surface chemistry on cell adhesion was evaluated.

Alumina-on-Polyethylene Bearing Surfaces in Total Hip Arthroplasty.

Science.gov (United States)

Jung, Yup Lee; Kim, Shin-Yoon

2010-02-11

The long-term durability of polyethylene lining total hip arthroplasty (THA) mainly depends on periprosthetic osteolysis due to wear particles, especially in young active patients. In hip simulator study, reports revealed significant wear reduction of the alumina ceramic-on-polyethylene articulation of THA compared with metal-on-polyethylene bearing surfaces. However, medium to long-term clinical studies of THA using the alumina ceramic-on-polyethylene are few and the reported wear rate of this articulation is variable. We reviewed the advantages and disadvantages of ceramicon- polyethylene articulation in THA, hip simulator study and retrieval study for polyethylene wear, in vivo clinical results of THA using alumina ceramic-on-polyethylene bearing surfaces in the literature, and new trial alumina ceramic-onhighly cross linked polyethylene bearing surfaces.

Effect of Ar ion on the surface properties of low density polyethylene

Science.gov (United States)

Zaki, M. F.

2016-04-01

In this paper, low-density polyethylene (LDPE) was irradiated by argon ion with different fluences up to 1015ions/cm2. The optical, chemical and hardness properties have been investigated using UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and micro-indentation tester, respectively. The results showed the ion beam bombardment induced decreases in the transmittance of the irradiated polymer samples. This change in transmittance can be attributed to the formation of conjugated bonds i.e. possible formation of defects and/or carbon clusters. The indirect optical band gap decreased from 3.0 eV for the pristine sample to 2.3 eV for that sample irradiated with the highest fluence of the Ar ion beam. Furthermore, the number of carbon atoms and clusters increased with increasing Ar ion fluences. FTIR spectra showed the formation of new bands of the bombarded polymer samples. Furthermore, polar groups were created on the surface of the irradiated samples which refer to the increase of the hydrophilic nature of the surface of the irradiated samples. The Vicker's hardness increased from 4.9 MPa for the pristine sample to 17.9 MPa for those bombarded at the highest fluence. This increase is attributed to the increase in the crosslinking and alterations of the bombarded surface into hydrogenated amorphous carbon, which improves the hardness of the irradiated samples. The bombarded LDPE surfaces may be used in special applications to the field of the micro-electronic devices and shock absorbers.

Influence of packaging atmosphere on the formation of cholesterol oxides in [gamma]-irradiated egg powder

Energy Technology Data Exchange (ETDEWEB)

Lebovics, V.K.; Gaal, O. (National Inst. of Food Hygiene and Nutrition, Budapest (Hungary)); Farkas, J.; Somogyi, L. (University of Horticulture and Food Industry, Budapest (Hungary))

1993-09-01

In the present work the influence of aerobic and anoxic conditions have been comparatively investigated to study the chemical changes of cholesterol in [gamma]-irradiated egg powder. The irradiation treatment was carried out with powdered egg packed under air and also under vacuum in polyethylene (PE) bags and in laminated, oxygen impermeable three-layer (polyester-aluminium-polyethylene) foil to dosage levels 2 and 4 kGy at room temperature. The cholesterol oxidation is demonstrated by thin-layer chromatograms. In the egg powder wrapped in Pe bags the predominant cholesterol derivatives -7-hydroxycholesterol isomers ([alpha] and [beta]) - accumulated in significant amounts (increasing with dose) while vacuum-packaging in laminated foil considerably suppressed the quantity of these products and prevented the formation of cholesterol 5[alpha], 6[alpha]-epoxide as well as 7-ketocholesterol. Little or no change was observed in non-irradiated (control) vacuum-packed egg powder stored at approximately 22[sup o]C for up to 5 months. Peroxide values showed changes parallel to the formation of COPs. (author).

Electron beam induced graft-polymerization of methyl methacrylate onto polyethylene films at high dose rates

International Nuclear Information System (INIS)

Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

1991-01-01

Electron beam induced graft-polymerization by the mutual irradiation technique of methyl methacrylate on the surface of low density polyethylene films (LD) and high density polyethylene films (HD) was investigated at high dose rates over 10 Mrad per second. Graft-polymerization mechanisms were discussed on the basis of O 2 permeability, tensile strength, elongation at break, and surface tension of the grafted films. As the degree of grafting increased, the O 2 permeability of LD decreased, while that of HD little changed at the grafting up to 4 ∼ 5 %. This indicates that the grafting occurred in the amorphous regions for LD and occurred in the amorphous regions in the neighborhood of crystalline regions for HD. For HD, when the degree of the grafting surpassed 4 ∼ 5 %, the O 2 permeability, tensile strength, elongation at break, and surface tension decreased with an increase in the degree of grafting. It was assumed that rapid grafting in the amorphous regions in the neighborhood of crystalline regions caused the increase in local temperature by the heat of polymerization, and the viscosity of polyethylene in the amorphous regions decreased with an increase in temperature. As a result, the graft chains, which formed micro domain structure, condensed in the amorphous regions and the domain increased in size. (author)

Crystallinity and the effect of ionizing radiation in polyethylene. V. Distribution of trans-vinylene and trans, trans conjugated double bonds in linear polyethylene

International Nuclear Information System (INIS)

Patel, G.N.

1975-01-01

Freeze-dried chain folded single crystals and the single crystals without amorphous surface layers (crystalline cores) of different thicknesses of linear polyethylene were irradiated with 60 Co γ-rays up to 600 Mrad. Concentration of trans-vinylene double bonds and conjugated diene produced during irradiation of the crystals was measured by infrared. Concentrations of trans-vinylene and of the conjugated diene were independent of thickness of crystalline core which suggest that the double bonds were randomly distributed in the crystalline parts of the crystals. Concentrations of trans-vinylene and of conjugated double bonds were lower in chain-folded crystals than in the crystalline cores and this suggests that the folds (amorphous surface layers) are less preferential sites for formation of the double bonds. The zero-order growth and first-order decay kinetics of trans-vinylene double bonds was studied by the equation derived by Dole et al. The equation is strictly obeyed up to 300 Mrad and the results then deviate. Since there is the decay of trans-vinylene double bonds and though there are no crosslinks in the crystalline cores, it has been suggested that the decay of the double bond does not result in the crosslinks

Characteristics of polyethylene and zirconium-hydride moderator for the NSRR tests

International Nuclear Information System (INIS)

Nakamura, Takehiko; Yamazaki, Toshi; Sobajima, Makoto.

1994-03-01

Pulse irradiation tests of FBR fuels under the sodium cooling conditions are planned for the phase III program in the NSRR (Nuclear Safety Research Reactor), following the phase I and II programs of the LWR fuel tests under the simulated RIA (Reactivity Initiated Accident) conditions. A proto-type irradiation capsule for the FBR fuel rod tests and a sodium loop to purify and to charge sodium into the capsule are under construction for the tests. In the NSRR tests, neutron moderator is needed to thermalize neutrons from the driver core and to subject transient energy high enough to cause the test fuel failure. The light water has been used for the NSRR LWR fuel tests as the coolant/moderator material. Polyethylene and zirconium-hydride are candidates of the moderator for the FBR fuel tests. The capability of the moderators are investigated in the pulse irradiation tests in the NSRR. Both of the moderators indicated good capability of realizing high thermal neutron flux to subject energy depositions comparable to the light water or higher. Estimations by the SRAC code system indicated reasonable good agreement with the test results. In addition, heating tests of the moderators did not cause gas decomposition nor dissociation, indicating that the moderators are operative at temperatures up to 300degC. (author)

Acoustic examinations of elastic and inelastic properties of high-pressure polyethylene with different radiation prehistory

International Nuclear Information System (INIS)

Kardashev, B.K.; Nikanorov, S.P.; Kravchenko, V.S.; Malinov, V.I.; Punin, V.T.

2007-01-01

The influence of vibrational deformation amplitude on the dynamic elasticity modulus and internal friction of high-pressure polyethylene samples with different histories is studied. Acoustic measurements are made by a resonance method using the longitudinal vibrations of a composite piezoelectric vibrator at a frequency of ∼ 100 kHz. It is found that the microplasticity remains almost unaffected upon irradiation and aging, while the elasticity modulus and breaking elongation per unit length considerably depend on the history and are clearly correlated with each other. The observed effects are explained by the fact that atom-atom interaction and defects inside polymer macromolecules substantially influence the elastic modulus and breaking strength, while the inelastic microplastic strain is most likely associated with molecule-molecule interaction, which is insignificantly affected by irradiation [ru

Distribution of products in polymer materials induced by ion-beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Sugimoto, Masaki; Kudoh, Hisaaki; Sasuga, Tsuneo; Seguchi, Tadao [Japan Atomic Energy Research Inst., Tokyo (Japan); Hama, Yoshimasa; Hamanaka, Ken-ichi; Matsumoto, Hideya

1997-03-01

The depth profile of double bond formed in low density polyethylene (LDPE) sheet by ion beams irradiation was observed by a micro FT-IR spectrometer in order to investigate the linear energy transfer (LET) dependency on radiation effects to polymer materials. The distribution of double bond formation in LDPE by irradiation of light ions as H+ was found to be same with the dose distribution calculated from TRIM code, and the yield was also same with that by gamma-rays irradiation, which means that the LET dependency is very small. However, the distribution of double bond to depth was much different from the calculated depth-dose in heavy ions irradiation as Ar and Kr. Then, the dose evaluation was difficult from the TRIM code calculation for heavy ions. (author)

Polyethylene/hydrophilic polymer blends for biomedical applications.

Science.gov (United States)

Brynda, E; Houska, M; Novikova, S P; Dobrova, N B

1987-01-01

Polyethylene blends with poly(2-hydroxyethyl methacrylate) [poly(HEMA)] or poly(2,3-dihydroxypropyl methacrylate) [poly(DHPMA)] were prepared by swelling polyethylene with HEMA or 2,3-epoxypropyl methacrylate (EPMA) and by polymerization of the respective monomers. Poly(EPMA) in blends was hydrolysed to poly(DHPMA) with acetic acid. The blends had similar surface and bulk compositions. Swelling with water and surface wettability were proportional to the content of the hydrophilic component; at the same content the polyethylene/poly(DHPMA) blends appeared more hydrophilic than those of polyethylene/poly(HEMA). Thrombus formation in contact with blood examined ex vivo and in vivo was considerably slower on the blends than on unmodified polyethylene. The tests indicated optima in composition; the best biological response was achieved with the blends containing about 14% poly(HEMA) or 16% poly(DHPMA).

Albedo and estimates of net radiation for green beans under polyethylene cover and field conditions

International Nuclear Information System (INIS)

Souza, J.L. de; Escobedo, J.F.; Tornero, M.T.T.

1999-01-01

This paper describes the albedo (r) and estimates of net radiation and global solar irradiance for green beans crop (Phaseolus vulgaris L.), cultivated in greenhouse with cover of polyethylene and field conditions, in Botucatu, SP, Brazil (22° 54' S; 48° 27' W; 850 m). The solar global irradiance (R g ) and solar reflected radiation (R r ) were used to estimate the albedo through the ratio between R r and R g . The diurnal curves of albedo were obtained for days with clear sky and partially cloudy conditions, for different phenological stages of the crop. The albedo ranged with the solar elevation, the environment and the phenological stages. The cloudiness range have almost no influence on the albedo diurnal amount. The estimation of radiation were made by linear regression, using the global solar irradiance (R g ) and net short-waves radiation (R c ) as independent variables. All estimates of radiation showed better adjustment for specific phenological periods compared to the entire crop growing cycle. The net radiation in the greenhouse has been estimated by the global solar irradiance measured at field conditions. (author) [pt

Conductive stability of graphene on PET and glass substrates under blue light irradiation

Science.gov (United States)

Cao, Xueying; Liu, Xianming; Li, Xiangdi; Lei, Xiaohua; Chen, Weimin

2018-01-01

Electrical properties of graphene transparent conductive film under visible light irradiation are investigated. The CVD-grown graphene on Polyethylene Terephthalate (PET) and glass substrates for flexible and rigid touch screen display application are chosen for research. The resistances of graphene with and without gold trichloride (AuCl3) doping are measured in vacuum and atmosphere environment under blue light irradiation. Results show that the conductivities of all samples change slowly under light irradiation. The change rate and degree are related to the substrate material, doping, environment and lighting power. Graphene on flexible PET substrate is more stable than that on rigid glass substrate. Doping can improve the electrical conductivity but induce instability under light irradiation. Finally, the main reason resulting in the graphene resistance slowly increasing under blue light irradiation is analyzed.

Influence of gamma irradiation on microbiological and chemical characteristics of shelled and unshelled stored pecan (carya illinoinsis)

International Nuclear Information System (INIS)

Abd El Wahab, S.A.E.; El Salhy, F.T.A.; Mahmoud, A.M.

2010-01-01

Shelled and unshelled pecan nuts were treated with 0,1.53 and 5 kGy of gamma irradiation . The irradiated and non-irradiated nuts were stored in polyethylene bags for 0,2,4,6, and 8 months at room temperature. Total bacterial count and total mold and yeast, proximate composition (moisture, protein, fat and ash content), total free amino acids, total fatty acids, reducing and non-reducing sugars, phosphorous and potassium of nuts were evaluated immediately after irradiation and after each storage period . The results indicated that gamma irradiation reduced total bacterial count and total fungal load of pecan. Irradiation doses did not cause any significant changes in proximate composition of pecan.

Thermal and optical excitation of trapped electrons in high-density polyethylene (HDPE) studied through positron annihilation

International Nuclear Information System (INIS)

Nahid, F.; Zhang, J.D.; Yu, T.F.; Ling, C.C.; Fung, S.; Beling, C.D.

2011-01-01

Positronium (Ps) formation in high-density polyethylene (HDPE) has been studied below the glass transition temperature. The formation probability increases with positron irradiation time due to an increasing number of inter-track trapped electrons becoming available for positron capture. The temperature variation of the saturated Ps level is discussed in different models. The quenching of trapped electrons by light has been studied and the optical de-trapping cross-section for different photon energies has been estimated over the visible region.

Ballistic behaviour of ultra-high molecular weight polyethylene: effect of gamma radiation

International Nuclear Information System (INIS)

Alves, Andreia L.S.; Nascimento, Lucio F.C.; Miguez Suarez, Joao Carlos

2004-01-01

The fiber reinforced polymer matrix composites (PMCs) are considered excellent engineering materials. In structural applications, when a high strength-to-weight ratio is fundamental for the design, PMCs are successfully replacing many conventional materials. Since World War II textile materials have been used as ballistic armor. Materials manufactured with ultrahigh molecular weight polyethylene (UHMWPE) fibers are used in the production of armor materials, for personnel protection and armored vehicles. As these have been developed and commercialized more recently, there is not enough information about the action of the ionizing radiation in the ballistic performance of this armor material. In the present work the ballistic behavior of composite plates manufactured with ultrahigh molecular weight polyethylene (UHMWPE) fibers were evaluated after exposure to gamma radiation. The ballistic tests results were related to the macromolecular modifications induced by the environmental degradation through mechanical (hardness, impact and flexure) and physicochemical (infrared spectroscopy, differential scanning calorimetry and thermal gravimetric analysis) tests. Our results indicate that gamma irradiation induces modifications in the UHMWPE macromolecular chains, altering the mechanical properties of the composite and decreasing, for higher radiation doses, its ballistic performance. These results are presented and discussed. (author)

Mathematical model of polyethylene pipe bending stress state

Science.gov (United States)

Serebrennikov, Anatoly; Serebrennikov, Daniil

2018-03-01

Introduction of new machines and new technologies of polyethylene pipeline installation is usually based on the polyethylene pipe flexibility. It is necessary that existing bending stresses do not lead to an irreversible polyethylene pipe deformation and to violation of its strength characteristics. Derivation of the mathematical model which allows calculating analytically the bending stress level of polyethylene pipes with consideration of nonlinear characteristics is presented below. All analytical calculations made with the mathematical model are experimentally proved and confirmed.

Improvement of mechanical and thermal properties of high energy electron beam irradiated HDPE/hydroxyapatite nano-composite

Science.gov (United States)

Mohammadi, M.; Ziaie, F.; Majdabadi, A.; Akhavan, A.; Shafaei, M.

2017-01-01

In this research work, the nano-composites of high density polyethylene/hydroxyapatite samples were manufactured via two methods: In the first method, the granules of high density polyethylene and nano-structure hydroxyapatite were processed in an internal mixer to prepare the nano-composite samples with a different weight percentage of the reinforcement phase. As for the second one, high density polyethylene was prepared in nano-powder form in boiling xylene. During this procedure, the hydroxyapatite nano-powder was added with different weight percentages to the solvent to obtain the nano-composite. In both of the procedures, the used hydroxyapatite nano-powder was synthesized via hydrolysis methods. The samples were irradiated under 10 MeV electron beam in 70-200 kGy of doses. Mechanical, thermal and morphological properties of the samples were investigated and compared. The results demonstrate that the nano-composites which we have prepared using nano-polyethylene, show better mechanical and thermal properties than the composites prepared from normal polyethylene granules, due to the better dispersion of nano-particles in the polymer matrix.

Gas production due to alpha particle degradation of polyethylene and polyvinylchloride

International Nuclear Information System (INIS)

Reed, D.T.; Hoh, J.; Emery, J.; Okajima, S.; Krause, T.

1998-07-01

Alpha particle degradation experiments were performed on polyethylene (PE) and polyvinylchloride (PVC) plastic samples typical of Westinghouse Savannah River Company (WSRC) transuranic (TRU) waste. This was done to evaluate the effects of sealing TRU waste during shipment. Experiments were conducted at three temperatures using low dose rates. Predominant products from both plastics were hydrogen, carbon dioxide, and various organic species, with the addition of hydrochloric acid from PVC. In all experiments, the total pressure decreased. Irradiation at 30 and 60 C and at various dose rates caused small changes for both plastics, but at 100 C coupled thermal-radiolytic effects included discoloration of the material as well as large differences in the gas phase composition

Hydrogen yield from polyethylene by radiolysis and the application to dosimeter

International Nuclear Information System (INIS)

Seguchi, T.

2006-01-01

The mechanisms and kinetics of hydrogen yield from polyethylene by γ-rays radiolysis were studied. As well known the major product from poly-olefins such as polyethylene is hydrogen and the yield tends to saturate with increase of dose. To understanding the saturation phenomena, the hydrogen yield from high molecular linear polyethylene was investigated quantitatively and proposed a mechanism of the saturation. The hydrogen yield from ultra-high molecular weight polyethylene showed the excellent reproducibility, therefore it is expected to be a high quality dosimeter. Materials were ultra-high molecular weight polyethylene (UHM-PE) and low-density polyethylene (LD-PE). UHM-PE is a linear chain and LD-PE contains branches such as ethyl- and butyl-groups in main chain. As the references, ethylene propylene copolymer rubber (EPR) and poly-isoprene (PIS) were examined. EPR has methyl-branches, and PIS contains double bonds in the main chain. The pure grade sample (less than 1g) was put in a glass tube and sealed off after evacuation, then irradiated by 60 Co γ-rays at a constant temperature. The dose was changed from 1 kGy to several MGy with a dose rate of 5 kGy/h. The accumulated gas in a glass tube was analyzed by gas chromatography. Mechanism of hydrogen evolution: The main gas was hydrogen for all polymers, and the miner gases were CH 4 , C 2 H 6 , C 3 H 8 , C 2 H 4 etc. H 2 content is 99.9% for UHM-PE, 99.1% for LD-PE, 98.8% for EPR, and 95% for PIS. The miner hydrocarbon gases are evolved by the C-C scission at branched chains or chain end. Therefore, the hydrocarbon gas from UHM-PE of linear long chain is negligibly small. For PE and EPR, H 2 yield increases linearly with dose up to 30 kGy, and tends to level off with increase of dose. G-value (H 2 ) is around 4-5 at linier line dose range for PE and EPR, and depends mainly on the crystallinity, that is, H 2 evolution is bigger in amorphous than crystalline part. The morphology of UHM-PE is scarcely changed

Effects of antioxidant and package materials on the quality of irradiated rugao ham

International Nuclear Information System (INIS)

Cao Hong; Chen Xiulan; Bao Jianzhong; Han Yan; Jiang Yunsheng; Wang Zhijun; Dong Jie; Yang Hairong; Xi Jun

2008-01-01

Irradiation could extend the shelf life of ham, but irradiation also facilitates the oxidation of fat. Different packaging materials and combination of antioxidants were used to deal with Rugao ham in order to lower the level of antioxidation caused by irradiation treatment. The peroxide value of fat was detected as the reference index. The results were indicated that the fat peroxide value of all samples increased within the storage of 100d, and then decreased. Aluminum film compound packaging showed a better effect than polyethylene plastic bag. The antioxideant combination of 0.5% tea-polyphenol, 0.5% Vc, 0.5% citric acid, 5% sodium alginate, applied on 4 kGy irradiated samples was measured the lowest peroxide value of fat among all the treatments. (authors)

Polymeric compositions incorporating polyethylene glycol as a phase change material

Science.gov (United States)

Salyer, Ival O.; Griffen, Charles W.

1989-01-01

A polymeric composition comprising a polymeric material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the composition is useful in making molded and/or coated materials such as flooring, tiles, wall panels and the like; paints containing polyethylene glycols or end-capped polyethylene glycols are also disclosed.

Poly[(ethylene oxide)-co-(methylene ethylene oxide)]: A hydrolytically-degradable poly(ethylene oxide) platform

OpenAIRE

Lundberg, Pontus; Lee, Bongjae F.; van den Berg, Sebastiaan A.; Pressly, Eric D.; Lee, Annabelle; Hawker, Craig J.; Lynd, Nathaniel A.

2012-01-01

A facile method for imparting hydrolytic degradability to poly(ethylene oxide) (PEO), compatible with current PEGylation strategies, is presented. By incorporating methylene ethylene oxide (MEO) units into the parent PEO backbone, complete degradation was defined by the molar incorporation of MEO, and the structure of the degradation byproducts was consistent with an acid-catalyzed vinyl-ether hydrolysis mechanism. The hydrolytic degradation of poly[(ethylene oxide)-co-(methylene ethylene oxi...

Alkaline Depolymerization of Polyethylene Terephthalate Plastic Waste

OpenAIRE

Ammar F. Abbas

2016-01-01

Depolymerization reaction is considered one of the most significant ways of converting waste polyethylene terephthalate in to terephthalic acid. The water polyethylene terephthalate bottle waste was collected from different places in Baghdad. The collection step shows that there is plenty amount of polyethylene terephthalate suitable to be an important source of terephthalic acid production.PET plastic waste conversion to terephthalic acid by depolymerization process was examined. The effect ...

Stock selection of high-dose-irradiation-resistant materials for filter press under high-dose irradiation operation

International Nuclear Information System (INIS)

Ishiyama, Shintaro; Minami, Mamoru; Hara, Kouji; Yamashita, Manabu

2015-01-01

In a volume reduction process for the decontamination of contained soil, the performance degradation of a filter press is expected owing to material deterioration under high-dose irradiation. Eleven-stock selection of candidate materials including polymers, fibers and rubbers for the filter press was conducted to achieve a high performance of volume reduction of contaminated soil and the following results were derived. Crude rubber and nylon were selected as prime candidates for packing, diaphragm and filter plate materials. Polyethylene was also selected as a prime candidate for the filter cloth material. (author)

The role of intramolecular crosslinking in the radiolysis of bulk crystallized high density polyethylene

International Nuclear Information System (INIS)

Lyons, B.J.

1986-01-01

Intramolecular crosslinks have been suggested to occur in bulk crystallized, irradiated, high density polyethylene (HDPE) and to account for the low rates of gel formation, especially those of previously annealed samples when compared with that manifested by the same resin when previously quenched from the melt. Such crosslinks do not contribute to the development of gel and contribute to only a limited extent to the elastic properties above the crystalline melting point when compared with intermolecular crosslinks, but, if the mesh size of the intra- and inter-molecular networks are comparable, are fully reflected in the rupture elongation. The rupture elongations of a wide range of HDPE resins, for a given sol fraction or elastic modulus, are found to be at least as high as and often higher than those of low (LDPE) or linear low (LLDPE) polyethylene resins, indicating that intramolecular crosslinking of this type does not occur to a significantly greater extent in these higher crystallinity resins. Other factors more likely to account for the reduced rates of inter alia gel formation in some HDPE resins are discussed. (author)

Characterization of the degree of cross-linking in radiation cross-linked low and high density polyethylenes

International Nuclear Information System (INIS)

Posselt, K.; Haedrich, W.

1986-01-01

In practice the cross-linking of irradiated polyethylene is mostly characterized by solubility and thermomechanical data. The irradiation of samples of a LDPE and a HDPE yields very different gel-dose curves. But for a quantitative comparison the complicated connection between the gel values and the corresponding densities of cross-links, especially the dependence on the initial molecular size distribution, has to take into consideration. The analysis of the solubility data according to the statistical theory of cross-linking developed by Inokuti and Saito shows that at equal doses in both investigated PE types in spite of the different gel values nearly the same densities of cross-links are present. That result is confirmed by the densities of cross-links determined from stress-strain measurements at 423 K. (author)

Polyethylene glycol: a game-changer laxative for children.

Science.gov (United States)

Alper, Arik; Pashankar, Dinesh S

2013-08-01

Constipation is a common problem in children worldwide. It can also be a chronic problem persisting for many months to years. Successful treatment of constipation requires long-term use of laxatives. Commonly used laxatives in children include milk of magnesia, lactulose, mineral oil, and polyethylene glycol. Compared with other laxatives, polyethylene glycol (with and without electrolytes) is a relatively new laxative used during the last decade. Recent studies report excellent efficacy and safety of polyethylene glycol for the long-term treatment of constipation in children. Because of excellent patient acceptance, polyethylene glycol has become a preferred choice of laxative for many practitioners. This article reviews the recently published pediatric literature on biochemistry, efficacy, safety, patient acceptance, and pharmacoeconomics of polyethylene glycol.

Ability of Bacillus subtilis protoplasts to repair irradiated bacteriophage deoxyribonucleic acid via acquired and natural enzymatic systems

International Nuclear Information System (INIS)

Yasbin, R.E.; Andersen, B.J.; Sutherland, B.M.

1981-01-01

A novel form of enzyme therapy was achieved by utilizing protoplasts of Bacillus subtilis. Photoreactivating enzyme of Escherichia coli was successfully inserted into the protoplasts of B. subtilis treated with polyethylene glycol. This enzyme was used to photoreactivate ultraviolet-damaged bacteriophage deoxyribonucleic acid (DNA). Furthermore, in polyethylene glycol-treated protoplasts, ultraviolet-irradiated transfecting bacteriophage DNA was shown to be a functional substrate for the host DNA excision repair system. Previous results (R.E. Yasbin, J.D. Fernwalt, and P.I. Fields, J. Bacteriol.; 137: 391-396) showed that ultraviolet-irradiated bacteriophage DNA could not be repaired via the excision repair system of competent cells. Therefore, the processing of bacteriophage DNA by protoplasts and by competent cells must be different. This sensitive protoplast assay can be used to identify and to isolate various types of DNA repair enzymes

The effects of irradiation on physicochemical characteristics of PET packaging film

International Nuclear Information System (INIS)

Jeon, D.H.; Lee, K.H.; Park, H.J.

2004-01-01

The effects of γ-irradiation on physicochemical characteristics of biaxially stretched poly(ethylene terephthalate) (PET) packaging film were investigated in the range of 0-200 kGy. The diethylene glycol (DEG) contents in PET chains were increased at the low doses, 5 and 10 kGy, while these values were decreased at high doses, in the range of 30-200 kGy. Molecular weights, intrinsic viscosity and carboxy end group contents decreased slightly after 60 kGy dose. Permeability, thermal properties, color, haze and surface resistivity on γ-irradiation of oriented PET films were not significantly affected. Although some of the effects were measurable, they have no significance with respect to the use of PET for packaging of foods or medical devices to be irradiated

Electron beam induced modifications in flexible biaxially oriented polyethylene terephthalate sheets: Improved mechanical and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Chaudhary, N. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Koiry, S.P. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Singh, A., E-mail: asb_barc@yahoo.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Tillu, A.R. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Jha, P.; Samanta, S.; Debnath, A.K. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Aswal, D.K., E-mail: dkaswal@yahoo.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Mondal, R.K. [Radiation Technology Development Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Acharya, S.; Mittal, K.C. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India)

2017-03-01

In the present work, we have studied the effects of electron beam irradiation (with dose ranging from 2 to 32 kGy) on mechanical and electrical properties of biaxially oriented polyethylene terephthalate (BOPET) sheets. The sol-gel analysis, Fourier transformation infra-red (FTIR), X-ray photoelectron spectroscopy (XPS) characterizations of the irradiated BOPET sheets suggest partial cross-linking of PET chains through the diethylene glycol (DEG). The mechanical properties of BOPET, such as, tensile strength, Young's modulus and electrical resistivity shows improvement with increasing dose and saturate for doses >10 kGy. The improved mechanical properties and high electrical resistivity of electron beam modified BOPET sheets may have additional advantages in applications, such as, packaging materials for food irradiation, medical product sterilization and electronic industries. - Graphical abstract: Irradiation of BOPET by electron beam leads to the formation of diethylene glycol that crosslink's the PET chains, resulting in improved mechanical properties and enhanced electrical resistivity. - Highlights: • BOPET exhibit improved tensile strength/Young's modulus after e-beam exposure. • Electrical resistivity of BOPET increases after e-beam exposure. • Cross-linking of PET chains through diethylene glycol was observed after e-beam exposure.

Biochemical changes in full fat rice bran stabilized through microwave heating and irradiation treatment

International Nuclear Information System (INIS)

El-Niely, H.F.; Abaullah, M.I.

2007-01-01

The effect of microwave heating and irradiation treatments on proximate composition, lipoxygenase (LOX) activity, free fatty acid (FFA) and fatty acids profile of full fat rice bran were examined. Full fat raw rice bran (FRB) (82.7 g / kg moisture content) was heated in microwave oven at 850 W for up to 4 min or exposed to gamma irradiation up to 25 KGy then packed in polyethylene bags and stored at room temperature for 6 months. Water, protein, fat, ash and crude fiber contents did not change significantly in raw, microwave heated and irradiated samples before and after storage. An exception for this general observation was observed for the moisture content of FRB processed through microwave heating where heating FRB for 4 min dropped the level of moisture to 64.3 g / kg at zero time. Storage of both raw and processed samples had significant (P<0.05) effects on LOX activity. LOX activity of raw samples was significantly increased from its initial value by 43.5% after storage for six months. Microwave heat and irradiated samples showed deactivated LOX and samples exhibited significant changes in LOX activity could be due to treatment dosage. Meanwhile, significant change in LOX activity was observed in processed samples stored for six months. Minor changes were observed due to applied processing methods on FFA and fatty acids composition of full fat rice bran before and after storage. The results suggested that microwave heated or irradiated full fat rice bran packed in polyethylene bags can be stored at room temperature for six months without adverse effect on proximate, fatty acid composition quality and could prevent oxidative and hydrolytic rancidity. However, gamma irradiation treatment at 25 KGy was more effective in this respect. Therefore, it could be concluded that gamma irradiation contributed to optimal processing conditions for FRB stabilization

21 CFR 172.260 - Oxidized polyethylene.

Science.gov (United States)

2010-04-01

... to 19. (b) The additive is used or intended for use as a protective coating or component of protective coatings for fresh avocados, bananas, beets, coconuts, eggplant, garlic, grapefruit, lemons, limes... Coatings, Films and Related Substances § 172.260 Oxidized polyethylene. Oxidized polyethylene may be safely...

Homocomposites of chopped fluorinated polyethylene fiber with low-density polyethylene matrix

International Nuclear Information System (INIS)

Maity, J.; Jacob, C.; Das, C.K.; Alam, S.; Singh, R.P.

2008-01-01

Conventional composites are generally prepared by adding reinforcing agent to a matrix and the matrix wherein the reinforcing agents are different in chemical composition with the later having superior mechanical properties. This work presents the preparation and properties of homocomposites consisting of a low-density polyethylene (LDPE) matrix and an ultra high molecular weight polyethylene (UHMWPE) fiber reinforcing phase. Direct fluorination is an important surface modification process by which only a thin upper layer is modified, the bulk properties of the polymer remaining unchanged. In this work, surface fluorination of UHMWPE fiber was done and then fiber characterization was performed. It was observed that after fluorination the fiber surface became rough. Composites were then prepared using both fluorinated and non-fluorinated polyethylene fiber with a low-density polyethylene (LDPE) matrix to prepare single polymer composites. It was found that the thermal stability and mechanical properties were improved for fluorinated fiber composites. X-ray diffraction (XRD) analysis showed that the crystallinity of the composites increased and it is maximum for fluorinated fiber composites. Tensile strength (TS) and modulus also increased while elongation at break (EB) decreased for fiber composites and was a maximum for fluorinated fiber composites. Scanning electron microscopic analysis indicates that that the distribution of fiber into the matrix is homogeneous. It also indicates the better adhesion between the matrix and the reinforcing agent for modified fiber composites. We also did surface fluorination of the prepared composites and base polymer for knowing its application to different fields such as printability wettability, etc. To determine the various properties such as printability, wettability and adhesion properties, contact angle measurement was done. It was observed that the surface energies of surface modified composites and base polymer increases

Absorbed Dose Distributions in Small Copper Wire Insulation due to Multiple-Sided Irradiations by 0.4 MeV Electrons

DEFF Research Database (Denmark)

Miller, Arne; McLaughlin, W. L.; Pedersen, Walther Batsberg

1979-01-01

When scanned electron beams are used to crosslink polymeric insulation of wire and cable, an important goal is to achieve optimum uniformity of absorbed dose distributions. Accurate measurements of dose distributions in a plastic dosimeter simulating a typical insulating material (polyethylene......) surrounding a copper wire core show that equal irradiations from as few as four sides give approximately isotropy and satisfactorily uniform energy depositions around the wire circumference. Electron beams of 0.4 MeV maximum energy were used to irradiate wires having a copper core of 1.0 mm dia....... and insulation thicknesses between 0.4 and 0.8 mm. The plastic dosimeter simulating polyethylene insulations was a thin radiochromic polyvinyl butyral film wrapped several times around the copper wire, such that when unwrapped and analyzed optically on a scanning microspectrophotometer, high-resolution radial...

Sterilization of Carriers by using Gamma Irradiation for Bio fertilizer Inoculum Production

International Nuclear Information System (INIS)

Tittabutr, Panlada; Teamtisong, Kamonluck; Pewlong, Wachiraporn; Teaumroong, Neuhg; Laoharojanaphand, Sirinart; Boonkerd, Nantakorn

2009-07-01

Full text: Gamma irradiation has been widely used in sterilization process, which leads to improvement in the quality of the products. In the case of bio fertilizer inoculum, the sterilized carrier is also needed for producing high quality bio fertilizer. This study aimed at determining the factors, such as carrier materials, moistures, and packing sizes including packaging materials that may affect the sterilization efficiency by using gamma irradiation. All carrier materials, peat and compost, could be efficiently sterilized by irradiation. The carriers that have moisture content lower than 20% could be sterilized by irradiation at 15 kGy, while carrier with 30% moisture content must be sterilized by irradiation at 25 kGy. Higher irradiation dose was also necessary for sterilization of bigger carrier packing sizes. For, packaging materials, polyethylene bag appeared most durable after gamma irradiation even at high doses. However, contaminants could be detected in irradiated carrier after storage at room temperature for two months. It was hypothesized that these contaminants are spore forming microorganisms, which resist gamma irradiation. This hypothesis, as well as the quality of bio fertilizer produced from irradiated carrier, will be further evaluated

Decontamination of spices by gamma irradiation

International Nuclear Information System (INIS)

Akhtar, T.; Khan, M.; Mahmood, F.; Sattar, A.

1995-01-01

Effect of gamma irradiation (8 kGy) on decontamination of pre packed (in polyethylene) and unpacked spices such as black pepper and chilli, was studied over a storage period of 12 months. Radiation dose of 8.0 kGyu completely decontaminated by the spices. Fungal packaged samples. Water content increased from a range values of 7.6-8.5% to 11.4 to 15.2% the increase was higher in red chilli than black pepper. Colour values significantly changed during storage, however the influence of radiation was not consistent. (author)

Nutritional Value of Irradiated Animal Feed By-Products

International Nuclear Information System (INIS)

El-Din Farag, M.D.H.

1998-01-01

Animal feed by-products, widely used in animal diets, are sources of disease organisms for animals and for human beings. Salmonella is the principal genus of concern.Radiation treatment (radicidation, radurization) is a promising method of decontamination of feed ingredients. Commercial samples of fish, meat, and blood meals were sealed by heat in polyethylene bags and irradiated at dose levels of 5.0, 10, 20 and 50 kGy. Their chemical analysis were carried out according to A. O. A.C [1] and the total protein efficiency (TPE) of the three animal feed by-products was determined according to Wood ham (2) by using one day old Dokki-4 chicks. Radiation induced an insignificant effect on the chemical constituent of meals. Also, the same trend was observed with TPE of both fish and meat meals. However, irradiation treatments improved TPE values of irradiated blood meal samples. From the results, it could be concluded that irradiation of animal feed by-products up to a dose level of 50 Gy has no adverse effects on the nutritional value of animal feed by-products

Use of L-cysteine for minimization of inorganic Hg loss during thermal neutron irradiation

International Nuclear Information System (INIS)

Anderson, D.L.

2009-01-01

Thermal neutron irradiation experiments performed with cellulose-based L-cysteine-treated and untreated Hg standards showed Hg losses of 59-81% for untreated standards but only about a 0.2% loss for treated standards. These results and others for multielement standards showed that Hg loss is highly dependent on total mass and placement of materials in the irradiation vessel and that distribution of volatilized Hg was fairly uniform throughout the sample-containing region of the vessel. Polyethylene trapped volatile Hg much more efficiently than cellulose and a multielement standard containing inorganic Se selectively trapped Hg lost from a co-irradiated multielement standard containing Hg. (author)

Removal of Heavy Metal Ions by Using Composite of Cement Kiln Dust/Ethylene Glycol co Acrylic Acid Prepared by y-Irradiation

International Nuclear Information System (INIS)

Sokker, H.H.; Abdel-Rahman, H.A.; Khattab, M.M.; Ismail, M.R.

2010-01-01

Various composites of cement kiln dust (CKD) and poly(ethylene glycol co acrylic acid) using y-irradiation was investigated. The samples were prepared using three percentages of cement kiln dust namely, 20, 50 and 75 by wt % and mixed with an equimolar ratio (1:1) of ethylene glycol and acrylic acid then irradiated at doses; 10,20 and 30 kGy of gamma-irradiation. The results showed that (CKD) and poly(ethylene glycol co acrylic acid) composites were formed only at 30 kGy. In addition, CKD alone has the lowest degree of removal of heavy metal ions compared with the prepared composites. A composite containing 75% cement kiln dust by weight percentage, showed the highest degree of removal of cobalt ions, whereas, a composite of 20% CKD showed the highest degree for cadmium ion removal. While the composite of 75% CKD showed a higher selectivity of cobalt ion than cadmium ion in their mixed solution.

Optical absorption in recycled waste plastic polyethylene

Science.gov (United States)

Aji, M. P.; Rahmawati, I.; Priyanto, A.; Karunawan, J.; Wati, A. L.; Aryani, N. P.; Susanto; Wibowo, E.; Sulhadi

2018-03-01

We investigated the optical properties of UV spectrum absorption in recycled waste plastic from polyethylene polymer type. Waste plastic polyethylene showed an optical spectrum absorption after it’s recycling process. Spectrum absorption is determined using spectrophotometer UV-Nir Ocean Optics type USB 4000. Recycling method has been processed using heating treatment around the melting point temperature of the polyethylene polymer that are 200°C, 220°C, 240°C, 260°C, and 280°C. In addition, the recycling process was carried out with time variations as well, which are 1h, 1.5h, 2h, and 2.5h. The result of this experiment shows that recycled waste plastic polyethylene has a spectrum absorption in the ∼ 340-550 nm wavelength range. The absorbance spectrum obtained from UV light which is absorbed in the orbital n → π* and the orbital π → π*. This process indicates the existence of electron transition phenomena. This mechanism is affected by the temperature and the heating time where the intensity of absorption increases and widens with the increase of temperature and heating time. Furthermore this study resulted that the higher temperature affected the enhancement of the band gap energy of waste plastic polyethylene. These results show that recycled waste plastic polyethylene has a huge potential to be absorber materials for solar cell.

Quantification of branching in model three-arm star polyethylene

KAUST Repository

Ramachandran, Ramnath; Beaucage, Gregory B.; Rai, Durgesh K.; Lohse, David J.; Sun, Thomas; Tsou, Andy; Norman, Alexander Iain; Hadjichristidis, Nikolaos

2012-01-01

The versatility of a novel scaling approach in quantifying the structure of model well-defined 3-arm star polyethylene molecules is presented. Many commercial polyethylenes have long side branches, and the nature and quantity of these branches varies widely among the various forms. For instance, low-density polyethylene (LDPE) is typically a highly branched structure with broad distributions in branch content, branch lengths and branch generation (in hyperbranched structures). This makes it difficult to accurately quantify the structure and the inherent structure-property relationships. To overcome this drawback, model well-defined hydrogenated polybutadiene (HPB) structures have been synthesized via anionic polymerization and hydrogenation to serve as model analogues to long-chain branched polyethylene. In this article, model 3-arm star polyethylene molecules are quantified using the scaling approach. Along with the long-chain branch content in polyethylene, the approach also provides unique measurements of long-chain branch length and hyperbranch content. Such detailed description facilitates better understanding of the effect of branching on the physical properties of polyethylene. © 2012 American Chemical Society.

Quantification of branching in model three-arm star polyethylene

KAUST Repository

Ramachandran, Ramnath

2012-01-24

The versatility of a novel scaling approach in quantifying the structure of model well-defined 3-arm star polyethylene molecules is presented. Many commercial polyethylenes have long side branches, and the nature and quantity of these branches varies widely among the various forms. For instance, low-density polyethylene (LDPE) is typically a highly branched structure with broad distributions in branch content, branch lengths and branch generation (in hyperbranched structures). This makes it difficult to accurately quantify the structure and the inherent structure-property relationships. To overcome this drawback, model well-defined hydrogenated polybutadiene (HPB) structures have been synthesized via anionic polymerization and hydrogenation to serve as model analogues to long-chain branched polyethylene. In this article, model 3-arm star polyethylene molecules are quantified using the scaling approach. Along with the long-chain branch content in polyethylene, the approach also provides unique measurements of long-chain branch length and hyperbranch content. Such detailed description facilitates better understanding of the effect of branching on the physical properties of polyethylene. © 2012 American Chemical Society.

Modification of ethylene-norbornene copolymer by Gamma irradiation

Directory of Open Access Journals (Sweden)

Kačarević-Popović Zorica M.

2006-01-01

Full Text Available The possibility of modifying polyethylene and many other polymers with high energy radiation has led to many useful applications. Due to their new combination of properties and the shortage of experimental data, the radiolysis of a new class of materials, cyclo-olefin copolymers (COC, polymerised from norbornene and ethylene using metallocene catalysts, is of great interest to the study of radiation chemistry and the physics of polymeric systems. Ethylenenorbornene copolymer, pristine and containing an antioxidant were subjected to gamma irradiation in the presence of air and in water. The irradiated copolymer was studied using IR and UV-vis spectrophotometric analysis. The radiation-induced changes in the molecular structure were correlated to changes in the glass transition temperature measured by the DSC method.

Alumina-on-Polyethylene Bearing Surfaces in Total Hip Arthroplasty

OpenAIRE

Jung, Yup Lee; Kim, Shin-Yoon

2010-01-01

The long-term durability of polyethylene lining total hip arthroplasty (THA) mainly depends on periprosthetic osteolysis due to wear particles, especially in young active patients. In hip simulator study, reports revealed significant wear reduction of the alumina ceramic-on-polyethylene articulation of THA compared with metal-on-polyethylene bearing surfaces. However, medium to long-term clinical studies of THA using the alumina ceramic-on-polyethylene are few and the reported wear rate of th...

New design of the pulsed electro-acoustic upper electrode for space charge measurements during electronic irradiation

Energy Technology Data Exchange (ETDEWEB)

Riffaud, J.; Griseri, V.; Berquez, L. [UPS, LAPLACE, Université de Toulouse, 118 Route de Narbonne, Toulouse F-31062, France and CNRS, LAPLACE, Toulouse F-31062 (France)

2016-07-15

The behaviour of space charges injected in irradiated dielectrics has been studied for many years for space industry applications. In our case, the pulsed electro-acoustic method is chosen in order to determine the spatial distribution of injected electrons. The feasibility of a ring-shaped electrode which will allow the measurements during irradiation is presented. In this paper, a computer simulation is made in order to determine the parameters to design the electrode and find its position above the sample. The obtained experimental results on polyethylene naphthalate samples realized during electronic irradiation and through relaxation under vacuum will be presented and discussed.

Optimized mounting of a polyethylene naphthalate scintillation material in a radiation detector.

Science.gov (United States)

Nakamura, Hidehito; Yamada, Tatsuya; Shirakawa, Yoshiyuki; Kitamura, Hisashi; Shidara, Zenichiro; Yokozuka, Takayuki; Nguyen, Philip; Kanayama, Masaya; Takahashi, Sentaro

2013-10-01

Polyethylene naphthalate (PEN) has great potential as a scintillation material for radiation detection. Here the optimum mounting conditions to maximize the light collection efficiency from PEN in a radiation detector are discussed. To this end, we have determined light yields emitted from irradiated PEN for various optical couplings between the substrate and the photodetector, and for various substrate surface treatments. The results demonstrate that light extraction from PEN is more sensitive to the optical couplings due to its high refractive index. We also assessed the extent of radioactive impurities in PEN as background sources and found that the impurities are equivalent to the environmental background level. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of γ-ray irradiation on the structure and melt fluidity of UHMWPE

International Nuclear Information System (INIS)

Liu Pengbo; Fan Ping; Xu Wen; Wang Kai

2005-01-01

Ultra-high molecular weight polyethylene (UHMWPE) was irradiated in air by 60 Co γ-rays. The effect of γ-ray irradiation on the structure and properties of UHMWPE was studied by FTIR, intrinsic viscosity measurement, melt flow rate (MFR) measurement and mechanical property test. The experimental results show that oxygen-containing groups (mainly carbonyl group) were introduced on the molecular chain of UHMWPE during the irradiation, which caused degradation of UHMWPE. Molecular weight of UHMWPE decreased and melt flow rate increased obviously. Compared with the virgin UHMWPE, MFR of the 100 kGy-irradiated UHMWPE increased from virtually nothing to 4.8 g/10 min. Tensile yield strength and elongation at break of the irradiated UHMWPE samples were improved, whereas notched lzod impact strength of the samples decreased. Compared with the virgin UHMWPE, elongation at break of the UHMWPE samples irradiated to 100 kGy increased from 367% to 801%, and their notched lzod impact strength decreased to 576 J/m from over 1000. (authors)

Post-{gamma}-irradiation reactions in vitamin E stabilised and unstabilised HDPE

Energy Technology Data Exchange (ETDEWEB)

Mallegol, J.; Carlsson, D.J. E-mail: dave.carlsson@nrc.ca; Deschenes, L

2001-12-01

The oxidation of high density polyethylene (HDPE), both unstabilised and vitamin E stabilised, has been studied by infrared (IR) and electron paramagnetic resonance (EPR) spectroscopies in the period following {gamma}-irradiation at doses from 1 to 60 kGy (range of food sterilisation). Derivatisation by reaction with sulphur tetrafluoride was used to identify macro-ketone and carboxylic acid components of the overlapped IR carbonyl region. Oxidation continued for several hundred hours after the cessation of irradiation as shown by the increase in hydroxyl, ketone and acid groups. Carboxylic acid groups are particularly important as a direct indication of backbone scission. Vitamin E, although an effective antioxidant during {gamma}-irradiation, was less effective in reducing the post-irradiation changes, which are probably driven by migration of radical sites along the polymer backbone from within the crystalline phase to the amorphous/crystalline inter-phase, where they become oxygen accessible.

Effects of Gamma Irradiation on Mechanical Properties of LDPE/Cassava Starch Blends

International Nuclear Information System (INIS)

Hemvichian, Kasinee; Suwanmala, Phiriyatorn; Kangsumrith, Wararat

2007-08-01

Full text: Low density polyethylene (LDPE) was blended with cassava starch. The starch content was varied from 10, 20 to 30%. The blends were compression molded to form plastic sheets. The sheets were cut into dog bone-shaped specimens. The samples were gamma irradiated in air with the total dose of 10, 20, 50 and 100 kGy. The mechanical properties of both the unirradiated and irradiated samples were characterized using a Universal Testing Machine. The results demonstrated that tensile strength of the LDPE/Starch blends increased with dose, while it simultaneously decreased with starch content

Development of nanocomposites employing high-density polyethylene and organo clay

International Nuclear Information System (INIS)

Lessa, Tathiane C. Rodrigues F.; Tavares, Maria Ines B.; Pita, Vitor J.R.R.

2009-01-01

The purpose of this study was to prepare nanocomposites of high-density polyethylene and montmorillonite organoclay by polymer melt intercalation, employing different processing parameters. Effective clay incorporation into polyethylene matrix was observed. The nanocomposites were structurally characterized. Intercalated nanocomposites were obtained from different process parameters, employing polyethylene resin and montmorillonite organoclays. The XRD results and other analysis showed that the processing parameters affect the organoclay delamination. The polyethylene nanocomposite presented the better performance using twin screw extruder, at 90 rpm. The purpose of characterization of polyethylene/organoclay nanocomposite by low-field NMR showed that this technique was important to understand changes in the molecular mobility of polyethylene when organoclay was incorporated. (author)

Effect of Ionizing Beta Radiation on the Mechanical Properties of Poly(ethylene under Thermal Stress

Directory of Open Access Journals (Sweden)

Bednarik Martin

2016-01-01

Full Text Available It was found in this study, that ionizing beta radiation has a positive effect on the mechanical properties of poly(ethylene. In recent years, there have been increasing requirements for quality and cost effectiveness of manufactured products in all areas of industrial production. These requirements are best met with the polymeric materials, which have many advantages in comparison to traditional materials. The main advantages of polymer materials are especially in their ease of processability, availability, and price of the raw materials. Radiation crosslinking is one of the ways to give the conventional plastics mechanical, thermal, and chemical properties of expensive and highly resistant construction polymers. Several types of ionizing radiation are used for crosslinking of polymers. Each of them has special characteristics. Electron beta and photon gamma radiation are used the most frequently. The great advantage is that the crosslinking occurs after the manufacturing process at normal temperature and pressure. The main purpose of this paper has been to determine the effect of ionizing beta radiation on the tensile modulus, strength and elongation of low and high density polyethylene (LDPE and HDPE. These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 99 kGy were compared and on the test temperature. Radiation cross-linking of LDPE and HDPE results in increased tensile strength and modulus, and decreased of elongation. The measured results indicate that ionizing beta radiation treatment is effective tool for improvement of mechanical properties of LDPE and HDPE under thermal stress.

Development of optimum process for electron beam cross-linking of high density polyethylene thermal energy storage pellets, process scale-up and production of application qualities of material

Science.gov (United States)

Salyer, I. O.

1980-01-01

The electron irradiation conditions required to prepare thermally from stable high density polyethylene (HDPE) were defined. The conditions were defined by evaluating the heat of fusion and the melting temperature of several HDPE specimens. The performance tests conducted on the specimens, including the thermal cycling tests in the thermal energy storage unit are described. The electron beam irradiation tests performed on the specimens, in which the total radiation dose received by the pellets, the electron beam current, the accelerating potential, and the atmospheres were varied, are discussed.

Macroradical reaction in ultra-high molecular weight polyethylene in the presence of vitamin E

International Nuclear Information System (INIS)

Jahan, M.S.; Walters, B.M.

2011-01-01

Free radical measurements in compression molded ultra-high molecular weight polyethylene (UHMWPE), which contained vitamin E (α-tocopherol (α-T)), was performed using electron spin resonance (ESR) technique in air at room temperature following gamma irradiation (25-32 kGy) in N 2 . The vitamin E was incorporated into one set of samples by blending UHMWPE resin with vitamin E (1 and 10 wt%), then compression molded into a solid and then irradiated. Another set of samples had vitamin E incorporated into them by diffusing vitamin E at 100 o C for 2 h after irradiation. Compared to a control (with no vitamin E), the vitamin E-containing UHMWPE (α-TPE) samples suffered a partial loss of PE radicals, but this loss only occurred during or immediately after irradiation (before exposure to air). Subsequently, when all blended samples were exposed to air, the remaining radicals in each sample decayed to the well-known OIR, R1 (- · CH-[CH=CH-] m -) and R2 ( · OCH-[CH=CH-] m -) radicals. However, because of the initial loss or partial quenching, α-TPE produced a lower concentration of OIR (measured over a four-year period), but no difference was found between 1% and 10% α-TPEs. In the diffused α-TPE, similar OIR was also found when tested after four months of post-treatment exposure to air.

Alkaline Depolymerization of Polyethylene Terephthalate Plastic Waste

Directory of Open Access Journals (Sweden)

Ammar F. Abbas

2016-02-01

Full Text Available Depolymerization reaction is considered one of the most significant ways of converting waste polyethylene terephthalate in to terephthalic acid. The water polyethylene terephthalate bottle waste was collected from different places in Baghdad. The collection step shows that there is plenty amount of polyethylene terephthalate suitable to be an important source of terephthalic acid production.PET plastic waste conversion to terephthalic acid by depolymerization process was examined. The effect of ethylene glycol amount, reaction time (up to 90 minutes and reaction temperature (from 70 to 170° C on the polyethylene terephthalate conversion was obtained.The kinetic study shows that the ordination of the depolymerization reaction of PET is first order irreversible reaction with 31103.5 J/mole activation energy.A 97.9 % terephthalic acid purity has been obtained by purification with N, N-dimethylformamide.

Effect of gamma irradiation on storability of apples (Malus domestica L.)

Energy Technology Data Exchange (ETDEWEB)

Al-Bachir, M [Atomic Energy Commission (AECS), Dept. of Radiation Agriculture, Damascus (Syrian Arab Republic)

1997-12-01

The effects of gamma irradiation on storability of two main apple varieties in Syria, Golden Delicious and Starking, were investigated. Fruits were irradiated with 0, 0.5, 1, and 1.5 kGy and combined irradiation with 1 kGy after packaging the fruits with polyethylene or paper bags. Irradiated and unirradiated fruits were stored at 1 to 2 C deg and 80 to 90% Rh. Weight loss and spoilage were evaluated throughout the different storage periods. Firmness, coloration and pH values were estimated immediately after irradiation. The results showed that in both varieties, gamma irradiation increased the weight loss after 45 days of storage in the 1995, but not in the 1996 season. After 180 days of storage gamma irradiation had different effects on weight loss depending on the season and variety, and increased the fungal spoilage. Application of gamma irradiation prevented the growth of Aspergillus niger and the formation of skin scald in Golden Delicious fruits. Immediately after treatment, gamma irradiation increased the softening of fruits, changed their colour from green to yellow and decreased the pH value of the juice. Combined treatments decreased the rate of weight loss and skin scald in Golden Delicious fruits and increased the fungal spoilage. (author)

Polyethylene Glycol 3350

Science.gov (United States)

... 3350 is in a class of medications called osmotic laxatives. It works by causing water to be ... experience either of them, call your doctor immediately: diarrhea hives Polyethylene glycol 3350 may cause other side ...

Development of shelf-stable meat sausages using gamma irradiation

International Nuclear Information System (INIS)

Seri Chempaka Mohd Yusof; Muhammad Lebai Juri; Mariani Deraman

2006-01-01

Irradiation techniques have been applied in development of ready to eat or shelf stable sausages. These sausages can be eaten directly without the need for prior heating or cooking procedure and displayed in the room temperature on the shelves of the retailers without frozen facilities. This study was designed to investigate the acceptability and microbial status of packed ready to eat sausages that had been sterilized using gamma irradiation at MINTec-Sinagama. Packed pre-cooked sausage samples (sealed in plastic-polyethylene individually) were irradiated with different doses of 2.5 kGy, 3.5 kGy and 5.5 kGy. Acceptability of the sausages was determined through sensory evaluation by 30 members of untrained panelists comprising of staffs of MINT. A 5 points hedonic rating scale was used. The attributes evaluated were rancidity, texture, chewiness, juiciness, aroma, colour, shape and overall acceptance. Samples irradiated with doses 3.5 kGy were the most acceptable followed by samples irradiated with doses 2.5 kGy and 5.5 kGy respectively. Irradiation with doses up to 2.5 kGy will virtually eliminate disease-causing microorganisms and pathogens. The total microbial count, detection of Salmonella, Escherichia coli, Staphylococcus aureus and fungi in these samples were determined and discussed. (Author)

Changes to the morphology, structure and properties as a consequence of polyethylene working in a polymer-metal kinematic pair

International Nuclear Information System (INIS)

Maszybrocka, Joanna; Cybo, Jerzy; Cwajna, Jan

2009-01-01

A change is presented of the orientation of lamellar structure, degree of crystallinity, the degree of the spatial arrangement of the structure, micromechanical properties, and the surface morphology and thickness of a plastically deformed upper layer. These changes are the effect of work in a polymer-metal kinematic pair, which have occurred as a result of plastic deformation of polyethylene during its service. It has been shown that, as a result of selecting proper parameters of UHMW polyethylene via the initial draft and electron-beam irradiation, such a structure of the polymer can be obtained, which will enable the above-mentioned changes in morphology and structure to take place during service. This in turn, will allow a reduction of the susceptibility of the polymer to permanent deformation by 3-6 times, and its wear by more than 5 times, compared to the initial material.

Alkaline Depolymerization of Polyethylene Terephthalate Plastic Waste

Directory of Open Access Journals (Sweden)

Ammar S. Abbas

2016-02-01

Full Text Available Depolymerization reaction is considered one of the most significant ways of converting waste polyethylene terephthalate in to terephthalic acid. The water polyethylene terephthalate bottle waste was collected from different places in Baghdad. The collection step shows that there is plenty amount of polyethylene terephthalate suitable to be an important source of terephthalic acid production. PET plastic waste converting to terephthalic acid by depolymerization process was examined. The effect of ethylene glycol amount, reaction time (up to 90 minutes and reaction temperature (from 70 to 170° C on the polyethylene terephthalate conversion was obtained. The kinetic study shows that the ordination of the depolymerization reaction of PET is first order irreversible reaction with 31103.5 J/mole activation energy. A 97.9 % terephthalic acid purity has been obtained by purification with N, N-dimethylformamide. Normal 0 false false false EN-US X-NONE AR-SA

Polyethylene-Based Tadpole Copolymers

KAUST Repository

Alkayal, Nazeeha

2017-02-15

Novel well-defined polyethylene-based tadpole copolymers ((c-PE)-b-PS, PE: polyethylene, PS: polystyrene) with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser coupling reaction. The -OH groups of the 3-miktoarm star copolymers (PE-OH)-b-PS, synthesized by polyhomologation and ATRP, are transformed to alkyne groups by esterification with propiolic acid, followed by Glaser cyclization and removal of the unreacted linear with Merrifield\\'s resin-azide. The characterization results of intermediates and final products by high-temperature size exclusion chromatography, H NMR spectroscopy, and differential scanning calorimetry confirm the tadpole topology.

Enhanced solid-phase photocatalytic degradation of polyethylene by TiO{sub 2}–MWCNTs nanocomposites

Energy Technology Data Exchange (ETDEWEB)

An, Yang [School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Xinjiang 832003 (China); Hou, Juan [College of Sciences, Shihezi University, Xinjiang 832003 (China); Liu, Zhiyong [School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Xinjiang 832003 (China); Peng, Banghua, E-mail: banghuapeng@hotmail.com [School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Xinjiang 832003 (China)

2014-11-14

In this work, a novel acid vapor method was introduced to prepare the water soluble multi-walled carbon nanotubes (MWCNTs) and the titanium dioxide (TiO{sub 2})–MWCNTs nanocomposites photocatalyst were successfully synthesized by sol–gel solvothermal method. Products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), which revealed that the anatase TiO{sub 2} particles were uniform deposited on MWCNTs surface. UV–vis diffuse reflectance spectroscopy (UV–vis) showed that composite photocatalyst had an obviously absorption band which covered the whole range of UV–vis region and exhibited a significant enhancement of optical absorption property. Based on above properties, we used the TiO{sub 2}–MWCNTs composites as photocatalysts to degrade the polyethylene (PE) plastic. Solid-phase PE film photocatalytic degradation experiments were investigated through monitoring TiO{sub 2}–MWCNTs–PE composite film's weight loss under mercury lamp irradiation. Results showed that the degradation efficiency could be tuned by changing the concentration of MWCNTs in photocatalyst. The photo-induced degradation of composite film was significantly higher than that of the pure PE film and the Degussa P25-PE film under the same UV irradiation. The weight loss of TiO{sub 2}–MWCNTs (20 wt%)–PE sample reached 35% under 180 h UV-light irradiation. Our work could be extended to synthesize other MWCNTs based composite with the purpose of enhancing TiO{sub 2}'s activity and inspiring for the practical environmental pollution, especially for degradation of plastics. - Highlights: • A novel acid vapor method was used to functionalize the MWCNTs. • Anatase nano-particles of TiO{sub 2} were uniform deposited on MWCNTs surface. • The composite photo-catalyst’s visible-light absorption capability was improved. • Polyethylene film's photodegradation efficiency was obviously enhanced

Mechanical Properties of Renewable Polymer with Thermoplastics Endurance to Ultraviolet irradiation Exposure

Directory of Open Access Journals (Sweden)

Salim Nurul Syamimi M.

2016-01-01

Full Text Available At present the disposal of waste tyre rubber (WTR has become a major waste management problem in the world. Therefore in this study, polymer blended based on Polyethylene which is Low Density Polyethylene (LDPE or High Density Polyethylene (HDPE, with Renewable Polymer (RP and waste tyre rubber (WTR is prepared via injection molding. Blended polymer such as LDPE/RP/WTR and HDPE/RP/WTR is known as LRT and HRT respectively. The preparation of polymer blend steps start with the preparation of RP. The RP is prepared by crosslinking the renewable monomer with Polymethane Polyphenyl Isocyanate (MDI at composition ratio of 1:0.5. The second steps involved by adding 10 gm of liquid RP prepared earlier on with fixed amount of LDPE and HDPE of 100 gm. Then the blended LDPE/RP or HDPE/RP namely as LR or HR respectively is further added with WTR with different percentages ratio of 5 %, 10 % and 15 %. The manually blended polymer mixture and filler is then melt mixing using injection moulding to fabricate the tensile specimen for mechanical tensile test and physical determination such as density, distribution of WTR in polymer blend and surface fracture morphology using scanning electron microscope. The samples were then exposed to UV irradiation exposure in UV Accelerated Weathering for 500, 1000, 1500, 2000, 2500 and 3000 hours to evaluate the photostability of the polymer blends. The optimum amount of WTR ratio composition is at 5 % for both LRT and HRT blends which indicate the stability of polymer blends towards UV irradiation exposure at 1000 hours.

Charging effects of PET under electron beam irradiation in a SEM

International Nuclear Information System (INIS)

Jbara, O; Rondot, S; Hadjadj, A; Patat, J M; Fakhfakh, S; Belhaj, M

2008-01-01

This paper deals with charge trapping and charge transport of polyethylene terephthalate (PET) polymer subjected to electron irradiation in a scanning electron microscope (SEM). Measurement of displacement current and leakage current using an arrangement adapted to the SEM allows the amount of trapped charge during and after electron irradiation to be determined and the charge mechanisms regulation to be studied. These mechanisms involve several parameters related to the electronic injection, the characteristics of insulator and the effects of the trapped charge itself. The dynamic trapping properties of PET samples are investigated and the time constants of charging are evaluated for various conditions of irradiation. The determination of the trapping cross section for electrons is possible by using the trapping rate at the onset of irradiation. Many physical processes are involved in the charging and discharging mechanisms; among them surface conduction is outlined. Through the control of irradiation conditions, various types of surface discharging (flashover phenomenon) behaviour are also observed. The strength of the electric field initiating surface discharge is estimated.

Radiation graft post-polymerization of sodium styrene sulfonate onto polyethylene

International Nuclear Information System (INIS)

Kitaeva, N.K.; Duflot, V.R.; Ilicheva, N.S.

2013-01-01

Post-irradiation grafting of sodium styrene sulfonate (SSS) in the presence of acrylic acid (AA) has been investigated on polyethylene (PE) pre-exposed to gamma radiation at room temperature in the air. Special attention was paid to the effect of low molecular weight salt additives on the kinetics of graft copolymerization of SSS and AA. The presence of SSS links in the grafted PE copolymers was detected by the methods of UV and FTIR spectroscopy. Based on the FTIR spectroscopy and element analysis data, a mechanism was proposed for graft copolymerization of SSS and AA onto PE. The mechanical properties of the graft copolymers were studied. It was established that PE copolymers grafted with sulfonic acid and carboxyl groups have higher strength characteristics (16.3 MPa) compared to the samples containing only carboxyl groups (11 MPa). (author)

Irradiation of dried-out fruits and vegetables in order to reduce boiling time and to improve rehydration degree

International Nuclear Information System (INIS)

Tencheva, S.

1975-01-01

Dried apples, prunes, carrots, red peppers and onion, packed in polyethylene bags of 100 g are irradiated on a gamma device with doses from 30 to 1500 krad. After irradiation the products are stored at room temperature in the dark for one year. Then the appearance (coloration) and taste of irradiated and control products are correlated. It is found that products irradiated with doses higher than 500 krad have a shorter boiling time. The degree of rehydration determined after the boiling method decreased only after irradiation with doses higher than 500 krad, which seems to be due to structural changes in the irradiated product. The inhibition quotients estimated after the soaking method also decreased only after high dose irradiation, when the products became essentially softer with increase in the amount of dry extract in the water used. (Ch.K.)

Preliminary results on neutron production from a Pb/U target irradiated by deuteron beam at 1.25 GeV/amu

International Nuclear Information System (INIS)

Fragopoulou, M.; Manolopoulou, M.; Jokic, S.; Zamani, M.; Krivopustov, M.; Sosnin, A.; Stoulos, S.

2008-01-01

A spallation neutron source consisted of a cylindrical Pb target and surrounded by uranium blanket was irradiated by deuteron beam 1.25 GeV/amu provided from the Nuclotron accelerator at High Energy Laboratory, JINR, Dubna. For radiation protection purpose a polyethylene shielding was placed around the spallation neutron source. Neutron distributions along the surface of the U-blanket were measured by using solid state nuclear track detectors (SSNTDs) as particle and fission detectors. The neutron distributions appear to be similar to those obtained by proton irradiations. Applying a fitting procedure to the experimental data the inelastic cross section of deuteron in Pb was estimated. The escaping neutron distribution from the polyethylene shielding and parallel to the target was also measured and presented to be two orders of magnitude less than that over the U-blanket surface

Radiolysis of the polyethylene/water system: Studies on the role of hydroxyl radical

Energy Technology Data Exchange (ETDEWEB)

Billamboz, Nicolas [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Grivet, Manuel, E-mail: manuel.grivet@univ-fcomte.f [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Foley, Sarah [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Baldacchino, Gerard [CEA, IRAMIS, SIS2M, Laboratoire de Radiolyse, Bat. 546, F-91191 Gif-sur-Yvette (France); CNRS, Laboratoire Claude Frejacques, F-91191 Gif-sur-Yvette (France); Hubinois, Jean-Charles [CEA, DAM, Valduc, F-21120 Is-sur-Tille (France)

2010-01-15

The role of hydroxyl radical on polyethylene degradation under aqueous conditions has been studied. The reactivity of HO{sup .} towards PE is highlighted by pulse radiolysis experiments on a PE powder suspension in water using the thiocyanate competition technique. Infrared analysis of PE films irradiated in the presence of water is performed. Solutions have been either degassed with Ar, in order to remove O{sub 2} which would react with the PE, or N{sub 2}O which enhances the production of HO{sup .} radicals. Oxygenated groups and double bond groups created at the surface of PE are characterized using IR analysis, and the results for both saturated solution systems are compared.

The effects of electron beam irradiation on additives present in food-contact polymers

International Nuclear Information System (INIS)

Crowson, Andrew.

1991-09-01

A range of additives (Irganox 1010, Irganox 1076, Irganox 1330, Irgafos 168 and Tinuvin 622) has been incorporated into a variety of food-contact polymers including polypropylene and low density polyethylene. Samples of these stabilized polymers were subjected to electron-beam or gamma irradiation to receive doses of 1,5,10,25 and 50 kGy. The effects of electron-beam irradiation on the amount of extractable antioxidant in polymers were determined. Using hplc techniques it was found that there was a dose-related reduction in the amount of extractable antioxidant similar to that caused by gamma irradiation. The magnitude of this reduction was found to be dependent upon the nature of both the antioxidant and the polymer type. Electron-beam irradiation was also found to cause a dose-related reduction in the levels of the antioxidants Irganox 1010 and Irganox 1076 migrating from polymers into a food simulant. This effect was similar to that caused by gamma irradiation. (author)

Study of electron beam irradiation effects on morphologic properties of the PET/PP/PE/EVA polymeric blend

International Nuclear Information System (INIS)

Rossini, Edvaldo L.; Silva, Leonardo G. Andrade e; Wiebeck, Helio

2009-01-01

Amidst the pollutants, plastics and especially the 'PET bottles' packaging type, which comprise of poly(ethylene terephthalate) (PET), polypropylene (PP), polyethylene (PE) and poly[ethylene-co-(vinyl acetate)] (EVA) have been causing big damage to the environment. In this work, the polymeric blend PET/PP/PE/EVA was obtained by mechanical recycling 'PET bottles' after consumption, with the objective of finding a solution for this environmental problem. It was also studied the different ionizing radiation dose effects (25, 50, 75, 100, 150, 200, 300, 400 and 500 kGy) on the blend properties using an electron beam accelerator. The morphologic properties of the non-irradiated and irradiated polymeric blend were evaluated by the Light Microscopy (LM) and Scanning Electron Microscopy (SEM). The analysis of the results appeared to be a not mixing and compatible blend. The use of the ionizing radiation improved the homogeneity of the blend. These modifications have been randomized and irregular, depending directly on the dose of applied radiation. (author)

Study of electron beam irradiation effects on morphologic properties of the PET/PP/PE/EVA polymeric blend

Energy Technology Data Exchange (ETDEWEB)

Rossini, Edvaldo L.; Silva, Leonardo G. Andrade e, E-mail: lgasilva@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Wiebeck, Helio, E-mail: hwiebeck@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica

2009-07-01

Amidst the pollutants, plastics and especially the 'PET bottles' packaging type, which comprise of poly(ethylene terephthalate) (PET), polypropylene (PP), polyethylene (PE) and poly[ethylene-co-(vinyl acetate)] (EVA) have been causing big damage to the environment. In this work, the polymeric blend PET/PP/PE/EVA was obtained by mechanical recycling 'PET bottles' after consumption, with the objective of finding a solution for this environmental problem. It was also studied the different ionizing radiation dose effects (25, 50, 75, 100, 150, 200, 300, 400 and 500 kGy) on the blend properties using an electron beam accelerator. The morphologic properties of the non-irradiated and irradiated polymeric blend were evaluated by the Light Microscopy (LM) and Scanning Electron Microscopy (SEM). The analysis of the results appeared to be a not mixing and compatible blend. The use of the ionizing radiation improved the homogeneity of the blend. These modifications have been randomized and irregular, depending directly on the dose of applied radiation. (author)

Reuse of polyethylene waste in road construction.

Science.gov (United States)

Raju, S S S V Gopala; Murali, M; Rengaraju, V R

2007-01-01

The cost of construction of flexible pavements depends on thickness of the pavement layers. The thickness of pavement mainly depends on the strength of the subgrade. By suitable improvement to the strength of the subgrade, considerable saving in the scarce resources and economy can be achieved. Because of their lightweight, easy handling, non-breakable and corrosion free nature, polyethylene have surpassed all other materials in utility. But polyethylene waste has been a matter of concern to environmentalists as it is non-biodegradable. In this investigation, an attempt has been made to study the improvement of California Bearing Ratio (CBR) value of soils stabilized with waste polyethylene bags. This alternative material is mixed in different proportions to the gravel and clay to determine the improvement ofCBR value. Use of the waste polyethylene bags observed to have a significant impact on the strength and economy in pavement construction, when these are available locally in large quantities.

Effects of irradiation temperature on polarisation and relaxation characteristics of polymeric materials

Energy Technology Data Exchange (ETDEWEB)

Bornstein, Marcel; Dutz, Hartmut; Goertz, Stefan; Reeve, Scott; Runkel, Stefan [Physikalisches Institut, Bonn Univ. (Germany)

2016-07-01

To achieve significant enhancement of polarisation of solid target materials one must use the principles of dynamic nuclear polarisation and utilise the coupling of the nuclear and electron spins. The unpaired electrons needed can be created as paramagnetic structural defects by irradiation of the material. Polyethylene and polypropylene materials were irradiated at various temperatures and subsequently polarised with microwaves of approximately 70 GHz at temperatures around 1 K. Additionally the samples were investigated with respect to the nature of the created paramagnetic defects using a X-band EPR spectrometer. It was found that the irradiation temperature has a significant effect on the polarisation values achieved and also on the relaxation times of the materials in the 2.5 T magnetic field. The EPR line shape is clearly dominated by the well known alkyl radical structure.

The acceptance of gamma irradiated pre-cooked processed chicken meat products

International Nuclear Information System (INIS)

Seri Chempaka Mohd Yusof; Muhamad Lebai Juri; Foziah Ali; Salahbiah Abdul Majida; Mariani Deraman; Ros Anita Ahmad Ramli; Rohaizah Ahmad; Zainab Harun; Abdul Salam Babji

2009-01-01

A study was carried out to determine suitable dose, microbiological counts including pathogens and sensory evaluation of pre-cooked chicken meat products in assessing the acceptability of irradiated pre-cooked chicken meat products. Packed pre-cooked chicken sausages and burger samples (sealed individually in plastic-polyethylene pouches) were irradiated at the following doses: 2.5 kGy, 3.5 kGy and 5.5 kGy using 60 Co gamma irradiation at MINTec-Sinagama. Acceptability of the sausages was determined through sensory evaluation by 30 members of untrained panelists comprising staff of Malaysian Nuclear Agency. A 5-points hedonic rating scale was used. The attributes evaluated were taste, texture, chewiness, juiciness, aroma, colour, shape and overall acceptance. Samples irradiated with dose of 5.5 kGy were the most acceptable, followed by samples irradiated at 3.5 kGy and 10 kGy. Irradiation at doses up to 3.5 kGy render undetectable microorganisms/fungi and pathogens (faecal coliforms, Salmonella sp., Escherichia coli and Staphylococcus aureus) in pre-cooked chicken sausages, and doses up to 5.5 kGy for pre-cooked chicken burgers

Thermal stability of radiation-modified polyethylene

International Nuclear Information System (INIS)

Vinogradova, T.B.; Sirota, A.G.; Bal'tenas, R.A.; Stanyavichus, V.I.; Knebel'man, A.M.; Sil'chenko, S.A.

1989-01-01

In the work reported here, the authors investigated the thermooxidative resistance, at temperatures from 373 to 473 K, of polyethylene that had been cross-linked by exposure to radiation and formulated with various heat stabilizers. Thus, these studies of the thermooxidative resistance of polyethylene-based compositions that have been cross-linked by the radiation-chemical method have shown that, in this particular series of heat-stabilizers, the greatest effect at temperatures of 373-473 K is given by the FAU-13. The DTPhDMI has the greatest heat-stabilizing effect in the temperature interval 448-473 K, whereas the heat resistance of materials containing Diaphen NN or Phenozan-23 is higher at 373-423 K. These comparative results are in agreement with data for unirradiated and chemically cross-linked polyethylene

Protective properties of radiation-modified polyethylene

Energy Technology Data Exchange (ETDEWEB)

Surnina, N.N.; Saltykova, L.A.; Strochkova, E.M.; Tatarenko, O.F.

1986-09-01

A study was made of the mass transfer of corrosive liquids and gases through polyethylene films modified by radiation surface grafting. Studies were performed on an unstabilized type A film with graft adhesion-active layer based on polymethacrylic acid. The protective properties of the polymer coating in corrosive fluids with low vapor tension were estimated by impedance measurements. Steel specimens with a protective coating of radiation-modified polyethylene film were exposed to 10% sulfuric acid at room temperature. The results indicated that the acid did not penetrate through to the metal surface. The films retain their protective properties and protect the metal from the acid. Radiation modification significantly improves the adhesion of polyethylene to metals without reducing physical and mechanical properties of the polymers. 50 references, 1 figure.

Irradiation in combination with low temperature storage for preservation of semi-dried mango and longan

Energy Technology Data Exchange (ETDEWEB)

Noomhorm, A; Karki, D B; Rao, M S [Agricultural and Food Engineering Program, School of Environment, Resources and Development, Asian Institute of Technology, Bangkok (Thailand)

1996-12-01

Semi dried mango (30% m.c.) and longan (16% m.c.) packed in low density polyethylene were irradiated at doses of 0, 2, 4, 6 and 8 kGy using Cobalt-60 and stored at 14 degree C and 30 degree C. Irradiation had no significant effect (p > 0.05) on acidity, total and reducing sugars, total carotenes, vitamin C content and sensory quality of the product. An irradiation dose of 2 kGy was sufficient to prevent the growth of microorganisms but a high dose of 8 kGy failed to reduce the viable yeast-mold count to neutrality. Irradiation of semi-dried mango and longan at a minimum dose of 2 kGy and subsequent storage at 14 degree C prolonged the shelf life without significant changes in quality

Irradiation in combination with low temperature storage for preservation of semi-dried mango and longan

International Nuclear Information System (INIS)

Noomhorm, A.; Karki, D.B.; Rao, M.S.

1996-01-01

Semi dried mango (30% m.c.) and longan (16% m.c.) packed in low density polyethylene were irradiated at doses of 0, 2, 4, 6 and 8 kGy using Cobalt-60 and stored at 14 degree C and 30 degree C. Irradiation had no significant effect (p > 0.05) on acidity, total and reducing sugars, total carotenes, vitamin C content and sensory quality of the product. An irradiation dose of 2 kGy was sufficient to prevent the growth of microorganisms but a high dose of 8 kGy failed to reduce the viable yeast-mold count to neutrality. Irradiation of semi-dried mango and longan at a minimum dose of 2 kGy and subsequent storage at 14 degree C prolonged the shelf life without significant changes in quality

Monoblock versus modular polyethylene insert in uncemented total knee arthroplasty

DEFF Research Database (Denmark)

Andersen, Mikkel Rathsach; Winther, Nikolaj; Lind, Thomas

2016-01-01

Background and purpose - Backside wear of the polyethylene insert in total knee arthroplasty (TKA) can produce clinically significant levels of polyethylene debris, which can lead to loosening of the tibial component. Loosening due to polyethylene debris could theoretically be reduced in tibial...

Making continuous bubble type polyethylene foam incombustible

International Nuclear Information System (INIS)

Kaji, Kanako; Hatada, Motoyoshi; Yoshizawa, Iwao; Komai, Kuniaki; Kohara, Choji.

1989-01-01

Since continuous bubble type plastic foam has excellent compression characteristics and sound absorption characteristics, it has been widely used as cushion material, sealing material, sound insulating material and so on. However, the most part of plastic foam is taken by air, therefore at the time of fires, it becomes a very dangerous material. At present, the material used mostly as the seat cushions for airliners, railroad coaches, automobiles and others is polyurethane foam, but since it contains C-N couples in its molecules, it is feared to generate cyanic gas according to the condition of combustion. As the plastic foam that does not generate harmful gas at the time of fires, there is continuous bubble type polyethylene which is excellent in its weathering property and chemical resistance. A reactive, phosphorus-containing oligomer has large molecular weight and two or more double couplings in a molecule, therefore, it does not enter the inside of polyethylene, and polymerizes and crosslinks on the surfaces of bubble walls in the foam, accordingly it is expected that the apparent graft polymerization is carried out, and it is very effective for making polyethylene foam incombustible. The method of making graft foam, the properties of graft foam and so on are reported. When the graft polymerization of this oligomer to continuous bubble type polyethylene foam was tried, highly incombustible polyethylene foam was obtained. (K.I.)

Macroradical reaction in ultra-high molecular weight polyethylene in the presence of vitamin E

Energy Technology Data Exchange (ETDEWEB)

Jahan, M.S., E-mail: mjahan@memphis.ed [Department of Physics, Biomaterials Research Laboratory, University of Memphis, 216 Manning Hall, Memphis, TN 38152 (United States); Walters, B.M. [Department of Physics, Biomaterials Research Laboratory, University of Memphis, 216 Manning Hall, Memphis, TN 38152 (United States)

2011-02-15

Free radical measurements in compression molded ultra-high molecular weight polyethylene (UHMWPE), which contained vitamin E ({alpha}-tocopherol ({alpha}-T)), was performed using electron spin resonance (ESR) technique in air at room temperature following gamma irradiation (25-32 kGy) in N{sub 2}. The vitamin E was incorporated into one set of samples by blending UHMWPE resin with vitamin E (1 and 10 wt%), then compression molded into a solid and then irradiated. Another set of samples had vitamin E incorporated into them by diffusing vitamin E at 100 {sup o}C for 2 h after irradiation. Compared to a control (with no vitamin E), the vitamin E-containing UHMWPE ({alpha}-TPE) samples suffered a partial loss of PE radicals, but this loss only occurred during or immediately after irradiation (before exposure to air). Subsequently, when all blended samples were exposed to air, the remaining radicals in each sample decayed to the well-known OIR, R1 (-{sup {center_dot}C}H-[CH=CH-]{sub m}-) and R2 ({sup {center_dot}O}CH-[CH=CH-]{sub m}-) radicals. However, because of the initial loss or partial quenching, {alpha}-TPE produced a lower concentration of OIR (measured over a four-year period), but no difference was found between 1% and 10% {alpha}-TPEs. In the diffused {alpha}-TPE, similar OIR was also found when tested after four months of post-treatment exposure to air.

Effect of irradiation on the properties of some shrinking polymer films

International Nuclear Information System (INIS)

Varsanyi, E.

1974-01-01

Shrinking polymer films (polyethylene, polyvinylidene chloride, polyester) suitable for use in the food industry were studied with the intention to determine the effect of radurizing doses (800 krad and below) on changes in the proportion of crystalline parts in the polymer, and on the tensile strength, elongation at break and shrinkage of the film. Changes in the crystalline/amorphous ratio in the polymer were determined by means of infra-red spectrophotometry. Calculations based on spectral data showed no significant changes in the ratio of crystalline fraction of any of the films, as a function of radurizing doses. Tensile strength and elongation at break tests were carried out by means of standardized instruments and methods. It was found that the tensile strength of the polyethylene film decreased by about 25% as an effect of irradiation, while the same treatment caused no significant changes in the elongation at break. The tensile strength of the polyvinylidene chloride film suffered a decrease of roughly 15%, its elongation at break an about 30% decrease when irradiated. Radiation treatment caused a decrease if less than 10% in tensile strength of the polyester film and a more than 10% change in elongation at break. The tests indicated no significant changes in the shrinkage of radiation treated polymers. The results of the tests led to the conclusion that radurizing doses caused no such change which would affect the applicability of polymer films to the wrapping and packaging of foods subjected to irradiation or would make the films unsuitable for the protection of the goods. (F.J.)

Preservation of ethnic food dodol combination of irradiation and atmosphere modified packaging

International Nuclear Information System (INIS)

Tanhindarto, Rindy P

1998-01-01

An investigation was conducted to determine the suitable types of modified atmosphere treatment combined with irradiation to extend the storage life of dodol at room temperature. The samples were obtained from the manufacture and the production date was known. The sample were vacuum-packed, vacuum-packed with N 2 , and vacuum-packed with CO 2 in polyethylene laminated nylon pouches. A part of the samples were unirradiated, and the irradiated ones received total doses of 2,5 and 5 kGy. The quality of the samples were determined by chemical, microbiological, and organoleptic test. The results showed that the three types of packaging combined with irradiation were not significant. The storage life of irradiation treatment with the doses of 2,5 and 5 kGy combined with modified atmosphere treatment dodol could be extended up to 10 and 12 months, respectively. For Unirradiated dodol, the storage life could be extended up to 8 months. (authors)

Gamma irradiation and heat treatment for sterilization of Mushroom Spent Compost (MSC)

International Nuclear Information System (INIS)

Rosnani Abdul Rashid; Hassan Hamdani Mutaat; Foziah Ali; Zainab Harun; Hoe, P.C.K.; Mohd Meswan Maskom; Khairuddin Abdul Rahim

2016-01-01

Mushroom spent compost (MSC) refers to substrate residue from mushroom cultivation. MSC can be used as a material to improve soil properties for farming. MSC is also suitable as a carrier or substrate to hold beneficial microorganisms in bio fertilizer products. The carrier for bio fertilizer products must be sterilized completely before inoculating with bacteria inoculum. In this study, the effects of gamma irradiation and heat on sterilization of MSC were evaluated by microbial enumeration technique. The MSC was packed into polyethylene bags. The packed MSC were irradiated at different doses of 0 (control), 10, 20, 30, 40, 50 kGy, and heat sterilized at different autoclaving time of 0 (control), 15, 30, 45 and 60 minutes, separately. The irradiated and autoclaved samples were enumerated for viable colonies. The results showed that MSC was completely sterilized by gamma irradiation at the dose of 30 kGy whilst sterilization by heat required 30 minute autoclaving time. (author)

Gamma irradiation for disinfestation of salted and dried fish

International Nuclear Information System (INIS)

Loaharanu, S.

1975-01-01

About 60-70% of commercially salted and dried fish were found to be infested by flies of 6 different species, i.e. the Cheese skipper (Piophila casei, L.) the Bronze bottle fly (Paenicia cuprina), the Screw worm fly (Chrysomya megacephala, Fab.), the Red-tailed flesh fly (Sarcophaga haemorrhoidalis, Fallen), Lucilia illustris, Meigen and Chrysomya marginalis, Weidemann. Larvae of the Cheese skipper were found to be the least radiation-sensitive, as 225 krad was required to prevent 99% of the larvae from developing into pupae. This dose was completely lethal to other developmental stages of the Cheese skipper and to all stages of other species. Irradiation at this doselevel also has some beneficial microbiological effects. Doses between 3 and 12,5 krad prevented larvae of all insects mentioned above from reaching the adult stage, though they did not inhibit the transition into the pupal form. No significant difference was observed on the organoleptic properties between salted and dried mackerel and Pla salid (Trichogaster pectoralis, Regan), a fresh water fish, irradiated up to 300 krad and those of untreated samples when tested up to 6 months of storage time at room temperature. Polypropylene bags of 0,13 and 0,20 mm thickness and polyethylene bags of 0,20 mm thickness could prevent re-infestation of the samples. Transportation tests by truck for a distance of 800 km revealed that both polypropylene and polyethylene bags of 0,13 and 0,20 mm thickness were suitable to package the mackerel samples but only polypropylene bags of 0,20 mm thickness were sufficient to protect the Pla salid samples. It appeared that salted and dried mackerel irradiated up to 300 krad and stored for 4 months was not considered rancid. No change in fat, protein and ash contents of irradiated samples was observed. It was concluded that gamma irradation could be considered as an effective method for disinfesting and preserving salted and dried fish. (author)

Effect of solubility parameter of monomers on electron beam induced graft-polymerization onto polyethylene films

International Nuclear Information System (INIS)

Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

1991-01-01

Electron beam induced graft-polymerization by the mutual irradiation technique of monomers with different solubility parameters δ onto low density polyethylene films (LDPE) and high density polyethylene films (HDPE) were investigated at high dose rates (25 Mrad per second). Graft-polymerization mechanisms were discussed on the basis of grafting rates, surface tensions, atomic ratios of surface by XPS, and SEM images of the grafted films. Grafting rates decreased with increasing δ of monomers, and grafting rates onto LDPE were larger than those onto HDPE. Graft chain contents on surface, which were evaluated in terms of surface tensions and atomic ratios of the surface, increased with increasing δ of monomers, and graft chain contents on surface of HDPE were higher than those of LDPE. It is assumed that mutual solubility of PE and monomers, i.e., infiltration of monomers into PE during graft-polymerization influence grafting rates and graft sites in films. In case of high mutual solubility, grafting rates were large and graft sites spread from the surface into bulk. On the other hand, in case of low mutual solubility, grafting rates were small and graft sites localized on the surface of films. (author)

Radiation-induced crosslinking of polyethylene in the presence of bifunctional vinyl monomers

Energy Technology Data Exchange (ETDEWEB)

Joshi, M.S.

1976-10-06

The apparent crosslinking produced by the radiation grafting of two monomers to polyethylene, acrylic acid and acrylonitrile, was investigated. Evidence is presented to show that covalent crosslinks are not produced during the radiation grafting step; covalent crosslinks are produced by the post-irradiation heat treatment associated with measurements of gel; the enhancement in gel fraction and physical properties arises from true crosslinks rather than chain entanglements; and there may be practical value associated with the sensitization of crosslinking produced by the methods employed in this work. The effect of monomer-solvent composition on the graft and gel yield was studied. Viscoelastic properties of grafted films were determined above the melting point of pure polyethylene. The kinetic data, infrared spectra, and viscoelastic properties are the bases for the following mechanism: (1) Acrylic acid-g-PE: Acrylic acid enters the film in the form of a hydrogen bonded dimer and undergoes a grafting reaction that produces hydrogen-bond crosslinks. The heat treatment during the conventional methods for determining of crosslinks convert them into intermolecular anhydride bonds. (2) Acrylonitrile-g-PE: In this, the post-grafting crosslinking is the result of a thermally induced chain reaction leading to an uninterrupted conjugated sequence. The length of the ring structure increases with time and temperature, and the intensity of color increases with the length of the ring structure.

Radiation-induced crosslinking of polyethylene in the presence of bifunctional vinyl monomers

International Nuclear Information System (INIS)

Joshi, M.S.

1976-01-01

The apparent crosslinking produced by the radiation grafting of two monomers to polyethylene, acrylic acid and acrylonitrile, was investigated. Evidence is presented to show that covalent crosslinks are not produced during the radiation grafting step; covalent crosslinks are produced by the post-irradiation heat treatment associated with measurements of gel; the enhancement in gel fraction and physical properties arises from true crosslinks rather than chain entanglements; and there may be practical value associated with the sensitization of crosslinking produced by the methods employed in this work. The effect of monomer-solvent composition on the graft and gel yield was studied. Viscoelastic properties of grafted films were determined above the melting point of pure polyethylene. The kinetic data, infrared spectra, and viscoelastic properties are the bases for the following mechanism: (1) Acrylic acid-g-PE: Acrylic acid enters the film in the form of a hydrogen bonded dimer and undergoes a grafting reaction that produces hydrogen-bond crosslinks. The heat treatment during the conventional methods for determining of crosslinks convert them into intermolecular anhydride bonds. (2) Acrylonitrile-g-PE: In this, the post-grafting crosslinking is the result of a thermally induced chain reaction leading to an uninterrupted conjugated sequence. The length of the ring structure increases with time and temperature, and the intensity of color increases with the length of the ring structure

Influence of low dose irradiation on the quality of fresh buffalo meat stored at 0-3 degrees C

International Nuclear Information System (INIS)

Naik, G.N.; Pushpa Paul; Chawla, S.P.; Sherikar, A.T.; Nair, P.M.

1994-01-01

The effect of low dose irradiation on the microbiological, chemical and sensory qualities of fresh buffalo meat stored at 0-3-degrees-C was studied. Meat slices packed in polyethylene bags subjected to 2.5 kGydose had a shelf-life of 4 weeks with acceptable sensory score, low total volatile basic nitrogen values and remarkable improvement in microbiological quality. Irradiated meat was completely free of Pseudomonas spp. and Enterobacteriaceae throughout storage. In contrast, the unirradiated control meat spoiled within 2 weeks

Elution behavior of poly(ethylene glycol) through poly(vinyl alcohol) gel column using several solvents as eluents

International Nuclear Information System (INIS)

Hirayama, Chuichi; Motozato, Yoshiaki; Matsumoto, Kazuaki.

1983-01-01

γ-Irradiated poly(vinyl alcohol) beads, which were sufficiently allowed to swell in water, were washed with methanol, and then were packed into column. Gel chromatography was performed using methanol, benzene, esters and ketones as eluents and poly(ethylene glycol) as a sample. When the elution was carried out using methanol and benzene as eluents, elution behavior of samples was ordinary. When ethyl formate, methyl acetate and ethyl propionate were used as eluents, samples were slightly adsorbed and the elution was delayed. In the case the elution was carried out using ethyl acetate, propyl acetate, butyl acetate and ethyl methyl ketone as eluents, samples were adsorbed strongly on the bed material, and the adsorption curve was analogous to the calibration curve using methanol as an eluent. Dried poly(vinyl alcohol) gel as a packing material, showed ordinary elution behaviors for the samples. The adsorption of poly(ethylene glycol) on the present bed material was attributed to the existence of hydrated water on poly(vinyl alcohol) gel matrix. (author)

Selective capillary diffusion of equimolar H2/D2 gas mixtures through etched ion track membranes prepared from polyethylene terephthalate and polyimide

International Nuclear Information System (INIS)

Schmidt, K.; Angert, N.; Trautmann, C.

1996-01-01

The selective capillary diffusion of equimolar H 2 /D 2 gas mixtures through ion track membranes prepared from polyethylene terephthalate and polyimide was investigated at a temperature of 293 K, a primary pressure of 0.15 MPa and a secondary pressure of 10 -4 MPa. Different values of the separation factor Z(H 2 /D 2 ) between experiment and computer simulation exists in the case of polyethylene terephthalate ion track membranes because of multiple pores. Membranes for which multiple pores were reduced by varying the irradiation angle showed an increased separation factor. The separation factor is a function of the pore diameter. This is shown for polyimide ion track membranes with a pore size in the range of 0.17 and 0.5 μm. After grafting with styrene the separation factor increased, indicating grafting within the pores. (orig.)

Studies on the properties of poly(ethylene oxide) R-150 water-swollen hydrogel formed by irradiation

International Nuclear Information System (INIS)

Yang Zhanshan; Zhu Nankang; Yang Shuqin; Qiang Yizhong

2000-01-01

The physical and chemical properties of PEO R-150 water-swollen hydrogel films formed by electron beam irradiation are studied and compared with PEO R-150 hydrogel films. The experimental results show that the irradiation dose and mass fraction of the polymer do not produce a significant effect on the gel fraction, of the PEO R-150 water-swollen hydrogel films (P>0.05). The degrees of swelling of the PEO R-150 water-swollen hydrogel films decrease as the irradiation dose increasing (P 0.05). The results indicate that the saturant crosslinking density, the lowest degree of swelling of the PEO R-150 water-swollen hydrogel films produce and unfavorable effect on their machinery strength

Low-dose gamma irradiation and refrigeration to extend shelf life of aerobically packed fresh beef round

International Nuclear Information System (INIS)

Rodriguez, H.R.; Lasta, J.A.; Mallo, R.A.; Marchevsky, N.

1993-01-01

A 2-kGy gamma (low-dose) irradiation was applied to fresh top round from beef animals slaughtered and fabricated at commercial facilities. Cuts were packed in polyethylene film and stored at 1 degree C. Temperature abuse (9 degrees C/24h) was simulated during storage. Psychrotroph counts on nonirradiated samples reached 10(7) CFU/cm between 8 and 11 d of storage, while similar counts were found after 28 d of storage on low-dose irradiated samples. Pseudomonads, Enterobacteriaceae, and Brochotrix thermosphacta were strongly inhibited on irradiated samples. No changes in organoleptic attributes were observed by a trained panel on treated samples. Low-dose irradiated samples had an average of 17 more shelf life days than the nonirradiated counterparts based on psychrotroph counts status and under the experimental condition being tested in this study

D-D nuclear fusion processes induced in polyethylene foams by TW Laser-generated plasma

Directory of Open Access Journals (Sweden)

Torrisi L.

2015-01-01

Full Text Available Deuterium-Deuterium fusion processes were generated by focusing the 3 TW PALS Laser on solid deuterated polyethylene targets placed in vacuum. Deuterium ion acceleration of the order of 4 MeV was obtained using laser irradiance Iλ2 ∼ 5 × 1016 W μm2/cm2 on the target. Thin and thick targets, at low and high density, were irradiated and plasma properties were monitored “on line” and “off line”. The ion emission from plasma was monitored with Thomson Parabola Spectrometer, track detectors and ion collectors. Fast semiconductor detectors based on SiC and fast plastic scintillators, both employed in time-of-flight configuration, have permitted to detect the characteristic 3.0 MeV protons and 2.45 MeV neutrons emission from the nuclear fusion reactions. From massive absorbent targets we have evaluated the neutron flux by varying from negligible values up to about 5 × 107 neutrons per laser shot in the case of foams targets, indicating a reaction rate of the order of 108 fusion events per laser shot using “advanced targets”.

The role of hydroperoxides as a precursor in the radiation-induced graft polymerization of methyl methacrylate to ultra-high molecular weight polyethylene

Energy Technology Data Exchange (ETDEWEB)

Enomoto, Ichiro, E-mail: enomoto.ichiro@iri-tokyo.j [Tokyo Metropolitan Industrial Technology Research Institute, KFC bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan); School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Katsumura, Yosuke [School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Ibaraki 319-1195 (Japan); Kudo, Hisaaki [School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Sekiguchi, Masayuki [Tokyo Metropolitan Industrial Technology Research Institute, KFC bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan)

2010-06-15

A graft polymerization of methyl methacrylate (MMA) to ultra-high molecular weight polyethylene (UHMWPE) with Co-60 gamma-ray irradiation in air at room temperature has been carried out. The grafting yields were measured as a function of the storage time (elapsed time from the end of irradiation to the start of grafting), and it was found that the yields reach at the maximum values at around several days since the end of irradiation. In order to clarify the precursor of the graft polymerization, changes of the radical yields and the carbonyl groups were measured as a function of storage time with ESR and microscopic FT-IR, respectively. From the similarities between the depth profiles of the hydroperoxide formation and the grafting products, it was concluded that the hydroperoxides can be main precursors of the grafting of the radiation-induced polymerization of MMA to UHMWPE under the given conditions.

The role of hydroperoxides as a precursor in the radiation-induced graft polymerization of methyl methacrylate to ultra-high molecular weight polyethylene

International Nuclear Information System (INIS)

Enomoto, Ichiro; Katsumura, Yosuke; Kudo, Hisaaki; Sekiguchi, Masayuki

2010-01-01

A graft polymerization of methyl methacrylate (MMA) to ultra-high molecular weight polyethylene (UHMWPE) with Co-60 γ-ray irradiation in air at room temperature has been carried out. The grafting yields were measured as a function of the storage time (elapsed time from the end of irradiation to the start of grafting), and it was found that the yields reach at the maximum values at around several days since the end of irradiation. In order to clarify the precursor of the graft polymerization, changes of the radical yields and the carbonyl groups were measured as a function of storage time with ESR and microscopic FT-IR, respectively. From the similarities between the depth profiles of the hydroperoxide formation and the grafting products, it was concluded that the hydroperoxides can be main precursors of the grafting of the radiation-induced polymerization of MMA to UHMWPE under the given conditions.

Effect of irradiation on quality, shelf life and consumer acceptance of traditional Nigerian meat and fish products

International Nuclear Information System (INIS)

Aworh, O.C.; Okparanta, R.N.; Oyedokun, E.O

2002-01-01

The effect of low dose irradiation, up to 6 kGy, on quality, shelf life and consumer acceptance of three traditional Nigerian meat and fish products was investigated. Irradiation inhibited microbial growth in 'suya' and 'kilishi' with substantial reduction in total aerobic counts, yeasts and molds and Staphylococcus aureus. Nonirradiated smoked-dried catfish (Clarias gariepinus) had a shelf life of less than one week at tropical ambient temperature (21-31 deg. C) due to insect infestation. Irradiated 'kilishi' and smoked dried catfish packed in sealed polyethylene bags (0.04 mm thick) were shelf stable for a period of 4-6 months and remained free from moldiness, infestation and were considered acceptable in sensory quality by a consumer panel of 32 assessors. There was a slight increase in TBA values of irradiated 'kilishi' stored for 4 months relative to non-irradiated controls. (author)

Ballistic behavior of ultra-high molecular weight polyethylene composite: effect of gamma radiation

International Nuclear Information System (INIS)

Alves, Andreia L. dos Santos; Nascimento, Lucio F.C.; Suarez, Joao C. Miguez; lucio2002bol.com.br

2003-01-01

Since World War II, textile composites have been used as ballistic armor. Ultra-high molecular weight polyethylene (UHMWPE) fibers are used in the production of armor materials. As they have been developed and commercialized only recently, there is not enough information about the effect of environmental agents in the ballistic performance of UHMWPE composites. In the present work, was evaluated the ballistic behavior of composite plates manufactured with UHMWPE fibers after exposure to gamma radiation. The ballistic tests results were related to the macromolecular alterations induced by the radiation through mechanical (hardness, impact and flexure) and physicochemical (Ftir/Mir. DSC and TGA) testing. It was observed that irradiation induces changes in the UHMWPE, degrading the ballistic performance of the composite. These results are presented and discussed. (author)

INAA study of Hg, Se, As, and Br irradiation losses from l-cysteine treated and untreated reference materials

International Nuclear Information System (INIS)

Anderson, D.L.

2013-01-01

U. S. Food and Drug Administration in-house reference material (RM) Cocoa Powder and National Institute of Standards and Technology Standard RMs (SRMs) 1515 apple leaves, 1547 peach leaves, 1571 orchard leaves, 1566a oyster tissue, and 1568a rice flour were co-irradiated together with polyethylene blanks and analyzed for Hg and Se by anticoincidence instrumental neutron activation analysis. The three botanical SRM portions showed a combined Hg recovery of 70 % while the other portions showed a combined Hg recovery of 169 %, indicating that volatile Hg was lost from botanical SRMs and absorbed by the other irradiated portions. Total Hg recovery for all portions was 82 %. Se results showed no evidence of cross-contamination and all results agreed with certified and known values. National Research Council of Canada Certified RMs DOLT-3 dogfish liver, TORT-2 lobster hepatopancreas, and DORM-3 fish protein were separately analyzed either with no treatment or after treatment with l-cysteine solutions followed by drying over magnesium perchlorate. Each set of portions was co-irradiated with polyethylene and treated filter blanks. Analysis of all components of each treated portion irradiation package showed that essentially all Hg was retained within the package. Treated DOLT-3 portions (inorganic Hg content 53 %) showed a tenfold improvement with 99 % Hg retention. Hg retention for DORM-3 (7 % inorganic Hg) was 85 % (a twofold improvement) while retention for TORT-2 (44 % inorganic Hg), was 94 %, similar to that for untreated portions (96 %). Small irradiation losses (≤0.5 %) of volatile species of Se, As, and Br were observed. (author)

Photografting of perfluoroalkanes onto polyethylene surfaces via azide/nitrene chemistry

Energy Technology Data Exchange (ETDEWEB)

Siegmann, Konstantin, E-mail: konstantin.siegmann@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland); Inauen, Jan, E-mail: jan.inauen@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland); Villamaina, Diego, E-mail: diego.villamaina@gmail.com [Visiting scientist at IMPE, Permanent address: Rapidplatz 3, CH-8953 Dietikon (Switzerland); Winkler, Martin, E-mail: martin.winkler@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland)

2017-02-28

The purpose of this study is to render polyethylene surfaces strongly and permanently hydrophobic. Polyethylene is a common plastic and, because of its inertness, difficult to graft. We chose polyethylene as example because of its ubiquity and model character. As graft chains linear perfluoroalkyl residues (−C{sub 4}F{sub 9}, −C{sub 6}F{sub 13}, −C{sub 8}F{sub 17} and −C{sub 10}F{sub 21}) were chosen, and photografting was selected as grafting method. Photolytically generated nitrenes can insert into carbon–hydrogen bonds and are therefore suited for binding to polyethylene. Hydrophobic photo reactive surface modifiers based on azide/nitrene chemistry are designed, synthesized in high yield and characterized. Four new molecules are described. Water contact angles exceeding 110° were achieved on grafted polyethylene. One problem is to demonstrate that the photografted surface modifiers are bound covalently to the polyethylene. Abrasion tests show that all new molecules, when photografted to polyethylene, have a higher abrasion resistance than a polyethylene surface coated with a long-chain perfluoroalkane. Relative abrasion resitances of 1.4, 2.0, 2.1 and 2.5 compared to the fluoroalkane coating were obtained for the four compounds. An abrasion model using ice is developed. Although all four compounds have the same λ{sub max} of 266 nm in acetonitrile solution, their molar extincition coefficients increase from 1.6·10{sup 4} to 2.2·10{sup 4} with increasing length of the fluorotelomer chain. Exitonic coupling of the chromophores of the surface modifiers is observed for specific molecules in the neat state. A linear correlation of water contact angle with fluorine surface content, as measured by photoelectron spectroscopy, in grafted polyethylene surfaces is established.

Application of electron beams irradiation in science and industry

International Nuclear Information System (INIS)

Hilmy, N.; Razzak, M.T.; Chosdu, R.; Soebianto, Y.S.

1996-01-01

The research and development of radiation technology in Indonesia is mainly conducted at the Center for Application of Isotopes and Radiation of the National Atomic Energy Agency (CAIR-BATAN). During the past 10 years, the center has gained a great progress in the development of gamma irradiation techniques for industrial processing, food preservation, health care products sterilization, and waste treatment. A low energy (300 keV, 50 mA) electron beam accelerator has been installed in cooperation with IAEA/UNDP as a training and demonstration facility for wood surface coating. In spite of the advantages of radiation curing, this technique is still unacceptable in the industries due to the uneconomical reasons and inferiority of the products. The research and development using this facility is also considered expensive, due to the high cost of the liquid nitrogen consumed by the accelerator. The medium energy (2 MeV, 10 mA) accelerator has been installed recently. This is a multipurpose irradiator provided with a belt conveyer, but also designed for wire and cable irradiation. The main technical parameters have been measured under different operating conditions during its commissioning, and the nominal dose measurement has been performed using alanine polyethylene, ethanol-chlorobenzene solution, and FWT-60 film dosimeters. Research and development of polymer cross-linking and shrinkable tubes have become the concern of the accelerator application. The radiation curable polyethylene compound for the cable insulation has been formulated with a characteristic of high voltage and heat resistant. Dosimetry of spices with 0.3-0.6 g/cm 3 density and health care products of 0.2-0.3 g/cm 3 density have been carried out for the promising food preservation and radiation sterilization, energy beam on micro-organism, and surface modification of some synthetic and natural polymers are also carried out. (J.P.N.)

Lifetime of Macroradicals in UHMWPE Irradiated with Electron Beam

International Nuclear Information System (INIS)

Costa, L.

2006-01-01

Interaction of high energy radiation with UHMWPE leads to the scission of C-C and C-H bonds both in the amorphous and in the criystalline phase, giving H radicals, macroradicals and trans vinylene double bonds. If oxygen is present, alkyl macroradicals react immediately with it and the oxidation chain process begins. In this case the main products are hydroperoxides. In our laboratory ultra high molecular weight polyethylene (medical grade GUR 1050) has been irradiated with electron beam in vacuum and in presence of oxygen at room temperature. Electron beam irradiation has been considered in order to neglect irradiation time, that is shorter (maximum 2 minutes) than gamma irradiation time and negligible compared to the following observation time. UHMWPE irradiated has been examined with two different techniques, FTIR and EPR spectroscopy. Micro FTIR Spectroscopy has been carried out on UHMWPE to evaluate hydroperoxide concentration in samples irradiated in presence of oxygen. Hydroperoxides and their distribution inside samples can be observed very well with FTIR microscopy after a derivatization process (with NO). The obtained hydroperoxide profile decreases when distance from the outer surface increases till it achieves a plateau. The first decrease can be attributed to macroradicals reaction with oxygen, that can diffuse only in the amorphous phase. Value obtained in the centre of block is correlated only with oxygen dissolved in UHMWPE before irradiation. If radicals live for some hours, oxygen can diffuse into UHMWPE during the macroradicals lifetime and the hydroperoxides profile is a curve similar to that obtained. Comparing the oxygen diffusion curve, calculated in the function of Fick's law, with the hydroperoxide profile, we have obtained a good agreement when oxygen diffusion is calculated over two hours. This means that the macroradicals must survive at least for two hours in the amorphous phase. EPR Spectroscopy was undertaken to explore the nature of

Measurement of radon permeability through polyethylene membrane using scintillation detector

Energy Technology Data Exchange (ETDEWEB)

Ashry, A.H.; Abou-Leila, M. [Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt); Abdalla, A.M., E-mail: aymanabdalla62@hotmail.co [Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt); Department of Physics, Faculty of Sciences and Arts, Najran University, Najran, P.O. Box. 11001 (Saudi Arabia); Advanced Materials and Nano-Engineering Laboratory (AMNEL), Centre for Advanced Materials and Nano-Engineering (CAMNE), Najran University, Najran, P.O. Box. 11001 (Saudi Arabia)

2011-01-15

The permeability of Radon 222 through polyethylene membranes has been studied using activated charcoal technique. The permeability constant of Radon 222 through low-density polyethylene, linear low-density Polyethylene and high density polyethylene samples has been measured. There is a considerable agreement between the values obtained by our method and the method suggested by W. Arafa [2002. Permeability of radon 222 through some materials. Radiat. Meas. 35, 207-211], and SSNTD technique suggested by A. Hafez and G. Somogyi [1986. Determination of radon and thoron permeability through some plastics by track technique. Int. J. Radiat. Appl. Instrum. Nucl. Track Radiat. Meas. 12 (1-6), 697-700]. In this work Radon permeability through different polyethylene membranes has been measured using three different methods, i.e. solid state nuclear track technique, W. Arafa [2002. Permeability of radon 222 through some materials. Radiat. Meas. 35, 207-211]method and our proposed method. In addition to this, in this study, the diffusion coefficient of radon in charcoal as well as solubility of Radon in polyethylene membrane has been taken into consideration.

Measurement of radon permeability through polyethylene membrane using scintillation detector

International Nuclear Information System (INIS)

Ashry, A.H.; Abou-Leila, M.; Abdalla, A.M.

2011-01-01

The permeability of Radon 222 through polyethylene membranes has been studied using activated charcoal technique. The permeability constant of Radon 222 through low-density polyethylene, linear low-density Polyethylene and high density polyethylene samples has been measured. There is a considerable agreement between the values obtained by our method and the method suggested by W. Arafa [2002. Permeability of radon 222 through some materials. Radiat. Meas. 35, 207-211], and SSNTD technique suggested by A. Hafez and G. Somogyi [1986. Determination of radon and thoron permeability through some plastics by track technique. Int. J. Radiat. Appl. Instrum. Nucl. Track Radiat. Meas. 12 (1-6), 697-700]. In this work Radon permeability through different polyethylene membranes has been measured using three different methods, i.e. solid state nuclear track technique, W. Arafa [2002. Permeability of radon 222 through some materials. Radiat. Meas. 35, 207-211] method and our proposed method. In addition to this, in this study, the diffusion coefficient of radon in charcoal as well as solubility of Radon in polyethylene membrane has been taken into consideration.

Degradation of polyethylene by Trichoderma harzianum--SEM, FTIR, and NMR analyses.

Science.gov (United States)

Sowmya, H V; Ramalingappa; Krishnappa, M; Thippeswamy, B

2014-10-01

Trichoderma harzianum was isolated from local dumpsites of Shivamogga District for use in the biodegradation of polyethylene. Soil sample of that dumpsite was used for isolation of T. harzianum. Degradation was carried out using autoclaved, UV-treated, and surface-sterilized polyethylene. Degradation was monitored by observing weight loss and changes in physical structure by scanning electron microscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. T. harzianum was able to degrade treated polyethylene (40%) more efficiently than autoclaved (23%) and surface-sterilized polyethylene (13%). Enzymes responsible for polyethylene degradation were screened from T. harzianum and were identified as laccase and manganese peroxidase. These enzymes were produced in large amount, and their activity was calculated using spectrophotometric method and crude extraction of enzymes was carried out. Molecular weight of laccase was determined as 88 kDa and that of manganese peroxidase was 55 kDa. The capacity of crude enzymes to degrade polyethylene was also determined. By observing these results, we can conclude that this organism may act as solution for the problem caused by polyethylene in nature.

Free radicals trapped in polyethylene matrix

International Nuclear Information System (INIS)

Shimada, S.; Maeda, M.; Hori, Y.; Kashiwabara, H.

1977-01-01

Two types of alkyl radicals were found to be trapped in irradiated crystals grown from polyethylene solution. One of them corresponds to the broad sextet pattern of the e.s.r. spectrum and the other corresponds to the sharp sextet pattern. The free radicals attributed to the broad sextet began to disappear at a lower temperature than the temperature at which the free radicals attributed to the sharp sextet disappeared. When butadiene molecules were brought into contact with the specimen, the decay of the free radicals corresponding to the broad sextet was accelerated. When the specimen was subjected to fuming nitric acid treatment, no broad sextet was observed. The mat of the crystals was aligned so that the c-axes of its crystallites were perpendicular to its surface. The broad sextet showed no anisotropy when the angle between the direction of applied magnetic field and that of the c-axis of the crystallite was varied. On the other hand, the sharp component of the spectrum showed apparent anisotropy. It can be concluded that the broad component comes from the free radicals trapped in the lamellar surface and the sharp component is attributed to the free radicals trapped in the inner part of the crystallite. (author)

Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acrylonitrile-butadiene rubber

Science.gov (United States)

Reinholds, Ingars; Kalkis, Valdis; Merijs-Meri, Remo; Zicans, Janis; Grigalovica, Agnese

2016-03-01

In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100-300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the kinetics of thermorelaxation and the residual shrinkage stresses of previously oriented (stretched up to 100% at above melting temperature of HDPE and followed by cooling to room temperature) specimens of irradiated HDPE/NBR blends under isometric heating-cooling mode. The compatibility between the both components was enhanced due to the formation of cross-linked sites at amorphous interphase. The results showed increase of mechanical stiffness of composites with increase of irradiation dose. The values of gel fraction compared to thermorelaxation stresses increased with the growth of irradiation dose level, as a result of formation cross-linked sites in amorphous PP/NBR interphase.

Poly[(ethylene oxide)-co-(methylene ethylene oxide)]: A hydrolytically-degradable poly(ethylene oxide) platform.

Science.gov (United States)

Lundberg, Pontus; Lee, Bongjae F; van den Berg, Sebastiaan A; Pressly, Eric D; Lee, Annabelle; Hawker, Craig J; Lynd, Nathaniel A

2012-11-20

A facile method for imparting hydrolytic degradability to poly(ethylene oxide) (PEO), compatible with current PEGylation strategies, is presented. By incorporating methylene ethylene oxide (MEO) units into the parent PEO backbone, complete degradation was defined by the molar incorporation of MEO, and the structure of the degradation byproducts was consistent with an acid-catalyzed vinyl-ether hydrolysis mechanism. The hydrolytic degradation of poly[(ethylene oxide)-co-(methylene ethylene oxide)] was pH-sensitive, with degradation at pH 5 being significantly faster than at pH 7.4 at 37 °C in PBS buffer while long-term stability could be obtained in either the solid-state or at pH 7.4 at 6 °C.

Polyethylene-waste tire dust composites via in situ polymerization

International Nuclear Information System (INIS)

Reyes A, Y. K.; Narro C, R. I.; Ramos A, M. E.; Neira V, M. G.; Diaz E, J.; Enriquez M, F.; Valencia L, L. A.; Saade C, H.; Diaz de L, R.

2014-01-01

Polyethylene/waste tire dust (WTD) composites were obtained by an in situ polymerization technique. The surface of the WTD was modified with deposition of polyethylene by using plasma polymerization. Ethylene polymerization was carried out using bis(cyclopentadienyl) titanium dichloride (Cp 2 TiCl 2 ) as homogeneous metallocenes catalyst, while diethylaluminum chloride (DEAC), ethyl aluminum sesquichloride (EASC) and methyl alumino xane (Mao) were used as co-catalysts at two different [Al]/[Ti] molar ratio. The main characteristics of the obtained polyethylenes were determined by size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry and wide-angle X-ray diffraction. The results showed that by using EASC and Mao the highest catalytic activities were presented at a [Al]/[Ti] molar ratio of 9.17 and 18.33 respectively. Even though it was possible to obtain polyethylene using WTD (modified or unmodified) the catalytic activity was lower than in the case in which no WTD was added in ethylene polymerization. Scanning transmission electronic microscopy images evidenced that the original morphology of the polyethylenes was not modified by the presence of WTD. (Author)

Polyethylene-waste tire dust composites via in situ polymerization

Energy Technology Data Exchange (ETDEWEB)

Reyes A, Y. K.; Narro C, R. I.; Ramos A, M. E. [Universidad Autonoma de Coahuila, Facultad de Ciencias Quimicas, Blvd. Venustiano Carranza s/n, 25280 Saltillo, Coahuila (Mexico); Neira V, M. G.; Diaz E, J.; Enriquez M, F.; Valencia L, L. A.; Saade C, H.; Diaz de L, R., E-mail: ramon.diazdeleon@ciqa.edu.mx [Centro de Investigacion en Quimica Aplicada, Blvd. Enrique Reyna Hermosillo No. 40, Col. San Jose de los Cerritos, 25293 Saltillo, Coahuila (Mexico)

2014-10-01

Polyethylene/waste tire dust (WTD) composites were obtained by an in situ polymerization technique. The surface of the WTD was modified with deposition of polyethylene by using plasma polymerization. Ethylene polymerization was carried out using bis(cyclopentadienyl) titanium dichloride (Cp{sub 2}TiCl{sub 2}) as homogeneous metallocenes catalyst, while diethylaluminum chloride (DEAC), ethyl aluminum sesquichloride (EASC) and methyl alumino xane (Mao) were used as co-catalysts at two different [Al]/[Ti] molar ratio. The main characteristics of the obtained polyethylenes were determined by size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry and wide-angle X-ray diffraction. The results showed that by using EASC and Mao the highest catalytic activities were presented at a [Al]/[Ti] molar ratio of 9.17 and 18.33 respectively. Even though it was possible to obtain polyethylene using WTD (modified or unmodified) the catalytic activity was lower than in the case in which no WTD was added in ethylene polymerization. Scanning transmission electronic microscopy images evidenced that the original morphology of the polyethylenes was not modified by the presence of WTD. (Author)

Polarization of electron-beam irradiated LDPE films: contribution to charge generation and transport

Science.gov (United States)

Banda, M. E.; Griseri, V.; Teyssèdre, G.; Le Roy, S.

2018-04-01

Electron-beam irradiation is an alternative way to generate charges in insulating materials, at controlled position and quantity, in order to monitor their behaviour in regard to transport phenomena under the space charge induced electric field or external field applied. In this study, low density polyethylene (LDPE) films were irradiated by a 80 keV electron-beam with a flux of 1 nA cm‑2 during 10 min in an irradiation chamber under vacuum conditions, and were then characterized outside the chamber using three experimental methods. The electrical behaviour of the irradiated material was assessed by space charge measurements using the pulsed electro-acoustic (PEA) method under dc stress. The influence of the applied electric field polarity and amplitude has been tested in order to better understand the charge behaviour after electron-beam irradiation. Fourier transform infra-red spectroscopy (FTIR) and photoluminescence (PL) measurements were performed to evaluate the impact of the electron beam irradiation, i.e. deposited charges and energy, on the chemical structure of the irradiated samples. The present results show that the electrical behaviour in LDPE after irradiation is mostly driven by charges, i.e. by physical process functions of the electric field, and that changes in the chemical structure seems to be mild.

Effects of electron irradiation on LDPE/MWCNT composites

Energy Technology Data Exchange (ETDEWEB)

Yang, Jianqun [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li, Xingji, E-mail: lxj0218@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Liu, Chaoming; Rui, Erming [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics, Harbin Institute of Technology, Harbin 150001 (China)

2015-12-15

In this study, mutiwalled carbon nanotubes (MWCNTs) were incorporated into low density polyethylene (LDPE) in different concentrations (2%, 4% and 8%) using a melt blending process. Structural, thermal stability and tensile property of the unirradiated/irradiated LDPE/MWCNT composites by 110 keV electrons were investigated by means of scanning electron microscopy (SEM), small angle X-ray scattering (SAXS), Raman spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, thermogravimetric analysis (TGA) and uniaxial tensile techniques. Experimental results show that the addition of MWCNTs obviously increases the ultimate tensile strength of LDPE and decreases the elongation at break, which is attributed to the homogeneous distribution of the MWCNTs in LDPE and intense interaction between MWCNTs and LDPE matrix. Also, the electron irradiation further increases the ultimate tensile strength of LDPE/MWCNT composites, which can be ascribed to the more intense interaction between MWCNTs and LDPE matrix, and the formation of crosslinking sites in LDPE matrix induced by the electron irradiation. The addition of MWCNTs significantly enhances thermal stability of the LDPE due to the hindering effect and the scavenging free radicals, while the electron irradiation decreases thermal stability of the LDPE/MWCNT composites since the structure of the MWCNTs and LDPE matrix damages.

Tensile mechanical response of polyethylene – clay nanocomposites.

Directory of Open Access Journals (Sweden)

2007-03-01

Full Text Available In this work we report on the microstructural and the mechanical characteristics of high density polyethylene (HDPE-clay nanocomposites, with particular attention to the creep behaviour. The samples were prepared through melt compounding, using two high-density polyethylenes with different melt flow rate (MFR, two different organo-modified clays, and changing the relative amount of a polyethylene grafted with maleic anhydride (PEgMA compatibilizer. The intercalation process is more effective as the matrix melt viscosity decreases (higher MFR, while the clay interlamellar spacing increases as the compatibilizer amount increases. The relative stiffness of the nanocomposites increases with the addition of clay, with a limited enhancement of the relative yield stress. The better intercalation obtained by the addition of the compatibilizer is not accompanied by a concurrent improvement of the tensile mechanical properties. The creep resistance is enhanced by the introduction of clay, with an appreciable dependence on both the polyethylene and the clay type.

Direct Synthesis of Telechelic Polyethylene by Selective Insertion Polymerization

KAUST Repository

Jian, Zhongbao; Falivene, Laura; Boffa, Giusi; Sá nchez, Sheila Ortega; Caporaso, Lucia; Grassi, Alfonso; Mecking, Stefan

2016-01-01

A single-step route to telechelic polyethylene (PE) is enabled by selective insertion polymerization. PdII-catalyzed copolymerization of ethylene and 2-vinylfuran (VF) generates α,ω-di-furan telechelic polyethylene. Orthogonally reactive exclusively

Effect of forming temperature conditions on the properties of radiation laced polyethylene films

Energy Technology Data Exchange (ETDEWEB)

Trizno, M S; Gasparyan, K A; Arutyunyan, G V; Borovko, V N

1978-11-01

The effect of radiation lace on the thermomechanical properties of polyethylene films depending on the radiation dose and temperature conditions of their formation was studied. The samples were produced at 160 deg under the pressure of 150 kN/m/sup 2/ with the following cooling in two temperature conditions: 1) cooling of the sample just after pressing in the icy water, and 2) slow cooling of the sample in a press. Films obtained using above conditions were subjected to the radiation lace in the argon medium using ..gamma..-radiation of /sup 60/Co at the exposure dose of 0.8x10/sup 6/ rad/hr. The total radiation dose was from 30 to 200 Mrad. It is shown that the films, obtained under the first cooling conditions have a lower degree of crystallinity. Investigations of gel-fraction content, density, elastic modulus, deformability, modulus of high elasticity, breaking stress, and relative elongation for rupture depending on radiation doze and the degree of crystallinity have shown that minimum degree of crystallinity of initial films provided most uniform adn compact net structure in the laced polyethylene(LP). In this case the material working capacity increases at high temperatures. In order to improve the mechanical properties of LP when exploiting it in the amorphous crystalline state it is recommended to irradiate material with maximum degree of crystallinity.

Equal channel angular extrusion of ultra-high molecular weight polyethylene

Energy Technology Data Exchange (ETDEWEB)

Reinitz, Steven D., E-mail: Steven.D.Reinitz.TH@Dartmouth.edu; Engler, Alexander J.; Carlson, Evan M.; Van Citters, Douglas W.

2016-10-01

Ultra-high molecular weight polyethylene (UHMWPE), a common bearing surface in total joint arthroplasty, is subject to material property tradeoffs associated with conventional processing techniques. For orthopaedic applications, radiation-induced cross-linking is used to enhance the wear resistance of the material, but cross-linking also restricts relative chain movement in the amorphous regions and hence decreases toughness. Equal Channel Angular Extrusion (ECAE) is proposed as a novel mechanism by which entanglements can be introduced to the polymer bulk during consolidation, with the aim of imparting the same tribological benefits of conventional processing without complete inhibition of chain motion. ECAE processing at temperatures near the crystalline melt for UHMWPE produces (1) increased entanglements compared to control materials; (2) increasing entanglements with increasing temperature; and (3) mechanical properties between values for untreated polyethylene and for cross-linked polyethylene. These results support additional research in ECAE-processed UHMWPE for joint arthroplasty applications. - Highlights: • A new processing method for ultra-high molecular weight polyethylene is introduced. • The process produces a highly entangled polyethylene material. • Entanglements are hypothesized to enhance the wear resistance of polyethylene. • This process eliminates the trade-off between mechanical and wear properties.

Dose dependent oxidation kinetics of lipids in fish during irradiation processing

International Nuclear Information System (INIS)

Tukenmez, I.; Ersen, M.S.; Bakioglu, A.T.; Bicer, A.; Pamuk, V.

1997-01-01

Kinetic aspects of the development of lipid oxidation in complex foods as fish in the course of irradiation were analyzed with respect to the associated formation of malonaldehyde (MA) through the reactions modified so as to be consistent with those in complex foods as fish. Air-packed anchovy (Engraulis encrasicholus) samples in polyethylene pouches were irradiated at the doses of 1, 2, 5, 10, 15,20 and 25 kGy at 20 o C in a Cs-137 gamma irradiator of 1.806 kGy/h dose rate. Immediately after each irradiation, MA contents of irradiated and unirradiated samples were determined by thiobarbituric acid test. Based on the MA formation, a kinetic model to simulate the apparent oxidation of lipid in fish as a function of irradiation dose was derived from the rate equations consistent with modified reactions. Kinetic parameters and simulation were related to conditions of lipid oxidation, and associated rancidity state of fish with respect to the doses applied in different irradiation-preservation processes. Numerical values of kinetic parameters based on the MA formation were found as a threshold dose of 0.375 kGy, an apparent yield of 1.871 μmol/kg kGy, and a maximum attainable concentration of 15.853 μmol/kg which may be used for process control and dosimetry. (author)

Investigation of reactivity changes due to flooding the irradiation sites of the MNSR reactor using the MCNP code and comparison with experimental results

Directory of Open Access Journals (Sweden)

A Shirani

2010-06-01

Full Text Available In this work, the Isfahan Miniature Neutron Source Reactor (MNSR has been simulated using the MCNP code, and reactivity worth of flooding the inner irradiation sites of this reactor in an accident has been calculated. Also, by inserting polyethylene capsules containing water inside the inner irradiation sites, reactivity changes of this reactor in same such accident have been measured, the results of which are in good agreements with the calculated results. In this work, the reactivity worth due to flooding one inner irradiation site is 0.53mk , and reactivity worth due to flooding of the whole 5 inner irradiation sites is 2.61 mk.

Development of highly fire-retardant irradiated polyolefin cables

Energy Technology Data Exchange (ETDEWEB)

Ueno, Keiji; Inui, Toshifumi; Uda, Ikujiro (Sumitomo Electric Industries Ltd., Osaka (Japan))

1982-12-01

In recent years, motors, automobiles, heaters, etc., have been made into light weight and compact form in view of labour-saving and energy-saving. For this purpose, the wires for the electrical appliances used for these equipment are required to reduce insulation thickness and to improve heat resistance. On the other hand, the requirement for fire-retardant property has become severer than before from the viewpoint of safety. As an insulation for the wires which meets such requirement, the polyolefin cross-linked by irradiation was investigated, and the heat-resistant, highly fire-retardant, polyolefin-insulated wires have been developed, which have passed vertical combustion test (VW-1) and have the insulation thickness of 0.4 mm (voltage rating 300V) and UL standard 125 deg C and 150 deg C grades. Fire-retardant polyolefin resin is normally obtained by adding halogen series flame retarders. The selection of flame retarders requires the investigation on high thermal stability, high flame retardation, no impedance to cross-linking, and good dispersion into polymers. The evaluation of heat resistance performed on two points, thermal aging and thermal deformation. The use of oxidation inhibitors is indispensable to improve the anti-thermal aging capability, but it is important to balance the requirements well by combining oxidation inhibitors, considering thermal deformation, colouring and discolouration. By comparative test with silicone rubber, cross-linked polyethylene and cross-linked PVC-insulated wires, the characteristics of highly fire-retardant wires, insulated with polyethylene cross-linked by irradiation, are described about the fire retardation, thermal deformation, thermal aging resistance, electrical characteristics and oil resistance.

Ion irradiation of AZO thin films for flexible electronics

Science.gov (United States)

Boscarino, Stefano; Torrisi, Giacomo; Crupi, Isodiana; Alberti, Alessandra; Mirabella, Salvatore; Ruffino, Francesco; Terrasi, Antonio

2017-02-01

Aluminum doped Zinc oxide (AZO) is a promising transparent conductor for solar cells, displays and touch-screen technologies. The resistivity of AZO is typically improved by thermal annealing at temperatures not suitable for plastic substrates. Here we present a non-thermal route to improve the electrical and structural properties of AZO by irradiating the TCO films with O+ or Ar+ ion beams (30-350 keV, 3 × 1015-3 × 1016 ions/cm2) after the deposition on glass and flexible polyethylene naphthalate (PEN). X-ray diffraction, optical absorption, electrical measurements, Rutherford Backscattering Spectrometry and Atomic Force Microscopy evidenced an increase of the crystalline grain size and a complete relief of the lattice strain upon ion beam irradiation. Indeed, the resistivity of thin AZO films irradiated at room temperature decreased of two orders of magnitude, similarly to a thermal annealing at 400 °C. We also show that the improvement of the electrical properties does not simply depend on the strain or polycrystalline domain size, as often stated in the literature.

Effect of ionizing radiation on nanocomposites of high density polyethylene with pseudoboehmite obtained by sol-gel process

International Nuclear Information System (INIS)

Miranda, Leila F.; Munhoz Junior, Antonio H.; Terence, Mauro C.; Alves, Alexandre P.

2009-01-01

Nanocomposites are polymeric hybrid materials where inorganic substances of nanometric dimensions are dispersed in a polymeric matrix. The fillers present area of raised surface, promoting better dispersion in the polymeric matrix and therefore an improvement of the physical properties of the composite that depends on the homogeneity of the material. The nanocomposites preparation with polymeric matrix allows in many cases to find a relation enters a low cost, due to the use of minor amount of filler, and a raised performance level. Nanocomposites were obtained with pseudoboehmite synthesized by sol-gel process and high density polyethylene with different concentrations of pseudoboehmite. The aim of this work was to study the effects of ionizing radiation on the properties of the nanocomposites obtained. The nanocomposites were prepared by melt intercalation technique and subsequently, the samples were molded by injection, irradiated and submitted to thermal and mechanical tests. The mechanical properties (impact strength and tensile strength), temperature of thermal distortion (HDT) and Vicat softening temperature of the non irradiated and irradiated nanocomposites were determined. The irradiation doses were of 30, 50 and 100kGy in a gamma cell. The results showed an increase in the values of tensile strength; a decrease in the impact strength and an increase in the temperature of thermal distortion (HDT) evidencing the interaction of nanofiller with the polymeric matrix. (author)

Study of the formation of polyethylene composites and lignocellulose materials by means of irradiation and extrusion

International Nuclear Information System (INIS)

Azevedo, Marcos Bertrand de; Romero, Guillermo R.; Gonzalez, Maria Elisa; Smolko, Eduardo E.

2000-01-01

One of the greatest opportunities for using of biomass as a precursor in the production of polymeric materials is the lignocellulose composites that can combine high performance with low costs. This work is a initial study on the production of a lignocellulose reinforced polyethylene composite. A compatibilization made by a induced gamma radiation grafting reaction was used to increase the adhesion between the matrix and the reinforced or filled fibers. The lignocellulose materials were exposed to gamma radiation in order to promote a molecular degradation and increase its reactivity. The polymer, the lignocellulose material and the compatibilization were processed by extrusion and the composite produced by this process were characterized by mechanical tests. (author)

Irradiation disinfestation of cowpea seeds to control southern cowpea beetle Callosbruchus maculatus (Fabricius) (Coleoptera Bruchidae)

International Nuclear Information System (INIS)

El-Kady, E.A.; Hekal, A.M.; El-Refai, S.

1987-01-01

The possibility of using gamma radiation as an alternative to fumigation or direct chemical applications for the control of stored-products insects was investigated in the laboratory and in a warehouse in Cairo, Egypt. Polyethylene bags of the type used in local markets were filled with cowpeas [Vigna unguiculata] Callosobruchus maculatus and irradiated at 400, 600 or 800 Gy [4, 6 or 8 krad]. All the treatments were effective, and no living adults infested by were found in the bags until 3 months later, when adults from outside penetrated the bags with their mandibles. It is therefore recommended that 4 krad should be administered for initial control, but that treated cowpeas should be stored in polypropylene rather than polyethylene bags in order to prevent reinfestation

Simple introduction of sulfonic acid group onto polyethylene by radiation-induced cografting of sodium styrenesulfonate with hydrophilic monomers

International Nuclear Information System (INIS)

Tsuneda, Satoshi; Saito, Kyoichi; Furusaki, Shintaro; Sugo, Takanobu; Makuuchi, Keizo

1993-01-01

The sulfonic acid (SO 3 H) group was readily introduced into a polyethylene (PE) membrane by radiation-induced cografting of sodium styrenesulfonate (SSS) with hydrophilic monomers such as acrylic acid (AAc) and hydroxyethyl methacrylate (HEMA). The density of SSS grafted onto the PE membrane was determined as a function of molar ratio of hydrophilic monomer to SSS in the monomer mixture. Immersion of the electron-beam-irradiated PE membrane into the mixture of SSS and HEMA for 5 h at 323 K provided to the SO 3 H density of 2.5 mol/kg of the H-type product

The effect of radiation-induced crosslinking on loss of Chimassorb 944 from (polyethylene-ethylene vinylacetate) blend in hot water

International Nuclear Information System (INIS)

Hassanpour, S.; Khoylou, F.

2006-01-01

Loss of a high molecular weight hindered amine light stabilizer (HALS) from irradiated low density polyethylene-ethylene vinyl acetate blends (LD/EVA) in hot water has been investigated. The effect of Chimassorb 944 and two trifunctional monomers, triallyloxy-1, 3,5-triazine and 2-ethyl-2-(hydroxymethyl)-1,3-propandiol-trimethacrylate on LD/EVA properties after irradiation and their effect on the stabilizer migration from the polymer base during thermal aging in hot water has been studied. The samples in both pure form and mixed with additives were exposed to electron beam radiation at doses between 100 and 150 kGy, at room temperature, in air. In order to study the thermal aging property, irradiated samples were placed in hot water bath at 95 deg C for 1000 hours and in an oven at 140 deg C for several hours. Irradiated samples showed noticeable changes in mechanical properties. Long term heat stability of polymer blend was improved significantly by using polyfunctional monomers. From the results of the thermal aging procedures, the HALS showed a convenient influence on the increase of the polymer blend thermal stability at 95 deg C. However under the accelerated conditions, the value of OIT decreased as a result of HALS depletion from the polymer base during immersion in hot water. (author)

Studies on gamma irradiated medicinal plants and spices (1): Myristica argentea, Myristica fragrans, Coriandrum sativum and Foeniculum vulgare

International Nuclear Information System (INIS)

Hilmy, Nazly; Chosdu, R.; Sudiro, S.; Syuib, F.

1981-01-01

Medicinal plants i.e. dried seeds of myristica argentea, myristica fragrans, coriandrum sativum and foeniculum vulgare were stored for 0 and 6 months, with and without gamma irradiation at 5 kGy. No detectable changes were seen in infrared and UV spectra, GLC chromatograms and refraction indeces of steam distilled, essential oils from the irradiated medicinal plants. The same results were also obtained from irradiated samples stored for 6 months at ambient conditions. Storage for 6 months caused significant changes in the gas liquid chromatograms and UV spectra of all samples compared to non-stored samples. The moisture content of all samples packed in polyethylene bags seems to be constant after 6 months of storage. No measurable changes were found in the amount of essential oil content caused by irradiation. (author)

Studies on gamma irradiated medicinal plants and spices (1): Myristica argentea, Myristica fragrans, Coriandrum sativum and Foeniculum vulgare

Energy Technology Data Exchange (ETDEWEB)

Hilmy, N; Chosdu, R; Sudiro, S [National Atomic Energy Agency, Jakartc (Indonesia). Pasar Djumat Research Centre; Syuib, F [Bandung Inst. of Tech. (Indonesia). Pharmacy Dept.

1981-10-01

Medicinal plants i.e. dried seeds of myristica argentea, myristica fragrans, coriandrum sativum and foeniculum vulgare were stored for 0 and 6 months, with and without gamma irradiation at 5 kGy. No detectable changes were seen in infrared and UV spectra, GLC chromatograms and refraction indices of steam distilled, essential oils from the irradiated medicinal plants. The same results were also obtained from irradiated samples stored for 6 months at ambient conditions. Storage for 6 months caused significant changes in the gas liquid chromatograms and UV spectra of all samples compared to non-stored samples. The moisture content of all samples packed in polyethylene bags seems to be constant after 6 months of storage. No measurable changes were found in the amount of essential oil content caused by irradiation.

Analysis of the radiolytic products on high-dose irradiated food and packing materials

International Nuclear Information System (INIS)

Kim, Kyong Su; Shim, Sung Lye; Chung, In Sun

2010-04-01

The aims of this study were to prepare the government approval for the extension of food irradiation item to food or its products, to promote the industrial application of radiation technology, and to apply basic data in policy for introduction of irradiation. The change of hydrocarbons by irradiation was evaluated for the detection of irradiated meat. The results showed that hydrocarbons were detected in all of irradiated samples, but these hydrocarbons were not detected in non-irradiated samples. There were no difference between vacuum and N 2 - packaging. According to fatty acid compounds and degradation pathway of beef and pork, it could be deliberated that a great amount of produced hydrocarbons such as 8-heptadenene and 1,7-hexadecadien were able to be used as identification factor of irradiated meat. Effects of γ-irradiation on the volatile organic compounds in agricultural products were determined by analyzing changes of volatile composition. The composition of volatile organic compounds were little changed, but few specific compounds induced by γ-irradiation were identified. The variations of concentration in irradiated samples identified in this study could be due to the radiation sensitivity of compounds with the dose used. Effects of γ-irradiation on the volatile compounds in packaging materials were determined by analyzing changes of volatile composition. In polyethylene and polypropylene, 1,3-DBB was identified only in irradiated samples. Levels of 1,3-DBB increased with increasing irradiation doses. These results suggest may be useful in evaluation of γ-irradiation effects on food packaging materials

Analysis of the radiolytic products on high-dose irradiated food and packing materials

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyong Su; Shim, Sung Lye; Chung, In Sun [Chosun University, Gwangju (Korea, Republic of)

2010-04-15

The aims of this study were to prepare the government approval for the extension of food irradiation item to food or its products, to promote the industrial application of radiation technology, and to apply basic data in policy for introduction of irradiation. The change of hydrocarbons by irradiation was evaluated for the detection of irradiated meat. The results showed that hydrocarbons were detected in all of irradiated samples, but these hydrocarbons were not detected in non-irradiated samples. There were no difference between vacuum and N{sub 2}- packaging. According to fatty acid compounds and degradation pathway of beef and pork, it could be deliberated that a great amount of produced hydrocarbons such as 8-heptadenene and 1,7-hexadecadien were able to be used as identification factor of irradiated meat. Effects of {gamma}-irradiation on the volatile organic compounds in agricultural products were determined by analyzing changes of volatile composition. The composition of volatile organic compounds were little changed, but few specific compounds induced by {gamma}-irradiation were identified. The variations of concentration in irradiated samples identified in this study could be due to the radiation sensitivity of compounds with the dose used. Effects of {gamma}-irradiation on the volatile compounds in packaging materials were determined by analyzing changes of volatile composition. In polyethylene and polypropylene, 1,3-DBB was identified only in irradiated samples. Levels of 1,3-DBB increased with increasing irradiation doses. These results suggest may be useful in evaluation of {gamma}-irradiation effects on food packaging materials

Keeping quality of raisins as affected by irradiation, storage environments and combination treatments

International Nuclear Information System (INIS)

Hussain, B.; Afridi, S.; Durrani, M.J.

1989-01-01

Influence of irradiation and storage environments on the quality of raisins was investigated during storage at room temperature for six months. Storage environment included: packaging in clear polyethylene bags in the presence of normal air, nitrogen and vacuum. Insect infestation appeared after two months storage and reached to 5.8, 8.6, 11.7 and 25.8% in the control samples stored in normal air for 3, 4, 5 and 6 months storage, respectively. No infestation was observed in vacuum nitrogen and packed samples. In irradiated samples no infestation was observed during storage in normal air and also vacuum and nitrogen packed samples. Raisin samples packed under vacuum were better in quality than other treatments. (author)

Application of polymers cross-linked by electron beam irradiation to electric wire industry

International Nuclear Information System (INIS)

Oda, Eisuke

1976-01-01

Applications of the polymers cross-linked by electron beam irradiation to electric wire industry as an example of dully developed utilization are reviewed. The report is divided into five parts, namely 1) radiation sources and irradiation processes, 2) development of crosslinking materials, 3) accumulation of electric charge and accumulation of heat, 4) examples of application, and 5) future prospect. Such a phenomenon as discharge destruction pattern (Lichtenberg figure) must be solved, when cable insulation materials are cross-linked by electron beam irradiation. The measures for preventing the discharge destruction are required, especially when the layers of polyethylene insulation for high voltage cables are irradiated. The accumulation of heat causes the troubles in foaming, degeneration and wire running of high potential cables, when the layers of insulation are thick. Effective promoters for cross-linking must be studied to reduce the radiation dose. The irradiators capable of irradiating wires uniformly are desirable. Electron beam accelerators will be used, as far as the radiation dose of 10 or more Mrad is required for cross-linking irradiation. If the dose of one tenth or less of the above value is required, gamma-ray sources (RI) are rather easily applicable than focused strong beam. The utilization of spent nuclear fuel is desirable. (Iwakiri, K.)

Preparation and characterization of polyethylene glycol diacrylate microgels using electron beam radiation

Energy Technology Data Exchange (ETDEWEB)

Hamzah, Mohd Yusof [Makmal Nanoteknologi, Bahagian Teknologi Sinaran (Malaysia); Isa, Naurah Mat; Napia, Liyana M. Ali [ALURTRON, Bahagian Kemudahan Iradiasi, Malaysian Nuclear Agency, 43000, Kajang, Selangor (Malaysia)

2014-02-12

The use of microemulsion in the development of nanosized gels based on polyethylene glycol diacrylate (PEGDA) is demonstrated. PEGDA was solubilized in n-heptane with use of sodium docusate (AOT) at 0.15M concentration to form reverse micelles. These micelles were than irradiated at 5, 10, 15, 20 and 25 kGy using electron beam (EB) to crosslink the entrapped polymer in the micelles. Ionizing radiation was imparted to the emulsions to generate crosslinking reaction in the micelles formed. The nanosized gels were evaluated in terms of particle diameter using dynamic light scattering (DLS) and the images of the nanosized gels were studied using transmission electron microscopy (TEM). Results show that the size and shape of the particles are influenced by concentration of PEGDA and radiation dose. This study showed that this method can be utilized to produce nanosized gels.

Irradiation of spices produced in Argentina

International Nuclear Information System (INIS)

Kairiyama, E.; Narvaiz, P.; Lescano, G.; Kaupert, N.L.

1988-01-01

Some spices produced in Argentina ground red pepper, anise, fennel, laurel, paprika, Cayenne pepper, cumin (seed), and mayoram (leaves and flowers), were irradiated to inactivate microbial lead, without causing significant chemical or sensory alterations. They were packed in polyethylene bags of 100 m thickness, and irradiated at the 60 Co semi-industrial facility of the Ezeiza Atomic Center, with doses of 7 and 10 kGy, and dose rate of 93.87 Gy/min. Dosimetric data were evaluated with potassium nitrate. Control and irradiated samples were stored at room temperature. Chemical analysis were performed to verify the Argentine Alimentary Codex specifications: water content; essence; total ash; ash insoluble in acid; alcoholic, volatile ether and non-volatile ether extracts; starch; and crude fiber. Besides, colour and volatile substances were analyzed. No differences were found between control and irradiated samples, with the exception of an increase in the total amount of volatiles released by irradiated spices, and a slight colour loss in mayoram. Microbiological determinations consisted of aerobic plate count, yeasts and moulds, coliform bacteria, Salmonella, Staphylococcus aureus, mesophilic and thermophilic sporeformers, enterococci and Clostridium perfringens. Microbial load in control samples oscillated between 10 3 and 10 6 microorganisms per gram, and was inhibited with 10 kGy to undetectable level. With 7 kGy, survivors were still detected in: cumin, anise, laurel, red pepper, fennel and paprika. So, the purpose of this work was accomplished with the dose of 10 kGy. Great improvement on the quality of those products which being stored at room temperature are consumed in the raw state, would be attained. (Author) [es

Preservation of squid rings by gamma irradiation. Microbiological, sensory and physicochemical aspects

International Nuclear Information System (INIS)

Tomac, A.; Yeannes, M.I.; Cova, M.C.; Narvaiz, Patricia

2011-01-01

The aim of this work was to analyze the use of gamma irradiation to preserve squid rings during refrigerated storage. Skinned rings of 'Illex argentinus' were packed in polyethylene/polyamide bags and gamma irradiated at 0, 2, 3 and 4 kGy with a cobalt-60 source at a semi-industrial irradiation facility. Samples were kept at 4 ± 1 °C during transportation, irradiation and 21 storage days. Mesophilic and psychrotrophic aerobic bacteria, Staphylococcus aureus, enterobacteriaceae, total coliforms, Escherichia coli, and sulphite-reducing clostridia were analyzed, as well as p H, total volatile basic nitrogen, color, and sensory parameters like aspect, color, odor, taste, texture and overall acceptability. Irradiation initially reduced three and two log cycles, respectively, of mesophilic and psychrotrophic bacterial counts, trend which was maintained during storage. Enterobacteriaceae and coliform growths were also controlled by this treatment. S. aureus, E. coli and sulphite-reducing clostridia were not detected in any sample. p H and TVBN values increased during storage time, being significantly lower in irradiated samples. Irradiation slowed down color changes during storage, measured as a* and b*. Color difference (DE2000) was significantly higher in control samples as compared to irradiated rings since the 6 th day. Sensory acceptability was not affected by gamma irradiation at any of the applied doses, being shelf-life extended at least 14 days in 3 kGy samples. (author) [es

Polyethylene solidification of low-level wastes

International Nuclear Information System (INIS)

Kalb, P.D.; Colombo, P.

1985-02-01

This topical report describes the results of an investigation on the solidification of low-level radioactive waste in polyethylene. Waste streams selected for this study included those which result from advanced volume reduction technologies (dry evaporator concentrate salts and incinerator ash) and those which remain problematic for solidification using contemporary agents (ion exchange resins). Four types of commercially available low-density polyethylenes were employed which encompass a range of processing and property characteristics. Process development studies were conducted to ascertain optimal process control parameters for successful solidification. Maximum waste loadings were determined for each waste and polyethylene type. Property evaluation testing was performed on laboratory-scale specimens to assess the potential behavior of actual waste forms in a disposal environment. Waste form property tests included water immersion, deformation under compressive load, thermal cycling and radionuclide leaching. Recommended waste loadings of 70 wt % sodium sulfate, 50 wt % boric acid, 40 wt % incinerator ash, and 30 wt % ion exchange resins, which are based on process control and waste form performance considerations are reported. 37 refs., 33 figs., 22 tabs

Comparison of Polyethylene Glycol-Electrolyte Solution vs Polyethylene Glycol-3350 for the Treatment of Fecal Impaction in Pediatric Patients.

Science.gov (United States)

Boles, Erin E; Gaines, Cameryn L; Tillman, Emma M

2015-01-01

The objective of this study was to evaluate the safety and efficacy of polyethylene glycol-electrolyte solution vs polyethylene glycol-3350 for the treatment of fecal impaction in pediatric patients. A retrospective, observational, institutional review board-approved study was conducted over a 1-year time period. Patients were included in the study if they were admitted to the hospital with a diagnosis of fecal impaction or constipation and were treated with either polyethylene glycol-electrolyte solution (PEG-ES) or polyethylene glycol-3350 (PEG-3350). Patients were excluded if they were discharged prior to resolution of treatment and/or did not receive PEG-ES or PEG-3350. Fifty-one patients (ranging in age from 1 month to 15 years) were evaluated: 23 patients received PEG-ES and 28 patients received PEG-3350. Sex, race, age, and weight were not statistically different between the 2 groups. Resolution of fecal impaction was not significantly different between PEG-ES vs PEG-3350 (87% and 86%, respectively; p = 0.87). There was only 1 reported side effect with PEG-3350, vs 11 reported side effects with PEG-ES (p PEG-3350 is as effective as PEG-ES for the treatment of fecal impaction in pediatric patients and is associated with fewer side effects.

Effects of gamma irradiation on pepper's volatile compounds sensory qualities and pest infestation control. Part of a coordinated programme in the Asian Regional Cooperative Project of Food Irradiation

International Nuclear Information System (INIS)

Khan, A.M.; Bahari Bin, I.

1984-04-01

The effects of gamma irradiation, packaging materials and storage time of black and white peppers on the infestation and reinfestation of microorganism and insects were evaluated. The samples were irradiated at the doses between 2 and 9 kGy. The packaging materials consisted of polypropylene woven bags laminated with thin polyethylene (PPE) and polyethylene bags (PE) of different thickness, 0.05, 01.2 and 0.17 mm. The jute bag was used as a control material. The changes of infestation and reinfestation status were observed for 6 months in Malaysia and for the next 2 months the changes were evaluated when the samples had reached Japan. Results obtained indicated that irradiation at a dose up to 9 kGy reduced the bacterial load of black pepper from 1.6x10 7 /g to 2 /g, while the dose of 6 kGy was required to reduce the population in white pepper from 2.3x10 4 /g to 2 /g. The original population of mould-yeast was relatively low (approx. 10 4 /g) and could be reduced to 2 /g at only 2 kGy. No problems and difficulties were faced with regard to the transportation of the peppers. However, prolonged storage time may encourage microbial growth, and 4 months of storage was a critical period for black pepper. Two species of Anobiidae infesting pepper had been identified, Lasioderma serricone (Fabricius) which made up 80% of the insect counts and Stegobium pamiceum (L.). However, at the doses applied and packaging materials used, there was no reinfestation for all but the material PPPE (no observation made for jute bags)

Surface functionalization of polyethylene via covalent immobilization of O-stearoyl-chitosan

International Nuclear Information System (INIS)

Xin, Zhirong; Hou, Juan; Ding, Jiaotong; Yang, Zongfeng; Yan, Shunjie; Liu, Chan

2013-01-01

When used in blood-contacting field, the hemocompatibility of polyethylene (PE) needs further to be improved. In this article, O-stearoyl-chitosans (OSC) with different esterification degrees were successfully prepared via changing the ratios of chitosan and stearoyl chloride for decreasing the cationic and hydrogen bond strength, thus improving the solubility of chitosan. The PE film was grafted with carboxyl groups of acrylic acid (AA) (PE-g-PAA) by means of O 2 plasma pre-treatment and UV-induced graft polymerization, and then PE-g-PAA was used for covalent immobilization of OSC. The above surface modification was confirmed by ATR-FTIR and XPS. Effect of the UV-irradiated graft polymerization parameters, i.e., the discharge power, the plasma pretreatment time, the UV irradiation time and the monomer concentration on the grafting density of AA was investigated. Relative to the value of about 107° for the virgin sample, the water contact angle (WCA) of the PAA-grafted film was about 50°. After the further immobilization of OSC onto the PAA-grafted film, the strength of negative charge of the PAA-grafted surface was decreased by the electropositive OSC, thus presenting a WCA value of about 62° and the excellent performance of anti-platelet adhesion with respect to the virgin and PAA-grafted samples.

Electric Charge Accumulation in Polar and Non-Polar Polymers under Electron Beam Irradiation

Science.gov (United States)

Nagasawa, Kenichiro; Honjoh, Masato; Takada, Tatsuo; Miyake, Hiroaki; Tanaka, Yasuhiro

The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula.

Electric charge accumulation in polar and non-polar polymers under electron beam irradiation

International Nuclear Information System (INIS)

Nagasawa, Kenichiro; Honjoh, Masato; Takada, Tatsuo; Miyake, Hiroaki; Tanaka, Yasuhiro

2010-01-01

The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m 3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m 3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m 3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula. (author)

Mechanical and thermal properties of commercial multilayer PET/PP film irradiated with electron-beam

International Nuclear Information System (INIS)

Ortiz, Angel V.; Nogueira, Beatriz R.; Oliveira, Vitor M.; Moura, Esperidiana A.B.

2009-01-01

The effects of electron-beam irradiation on mechanical and thermal properties, for one commercial flexible food packaging multilayer structure, were studied. The laminated poly(ethylene terephthalate) (PET)/ polypropylene (PP) structure was irradiated up to 60 kGy, using a 1.5 MeV electron beam accelerator, at room temperature in the presence of air. Mechanical properties showed significant changes (p < 0.05). In addition, the DSC analysis, after treatment, showed that the fusion enthalpy and crystallinity of the PET/PP structure components presented significant changes (p < 0.05) with the electron-beam radiation doses applied. It was observed an increase in PP crystallinity while the PET crystallinity decreases. Such decrease in PET crystallinity indicates the predominance of a cross-linking process on the irradiated PET layer; responsible for the increase in some mechanical properties of the studied film. (author)

Thermogravimetric studies of the thermooxidative stability of irradiated and unirradiated polyethylene. Pt. 1. Effect of antioxidant

Energy Technology Data Exchange (ETDEWEB)

Gal, O; Novakovic, Lj [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia); Stannett, V T [North Carolina State Univ., Raleigh (USA)

1983-01-01

The addition of antioxidants to polymers increases their thermooxidative stability as indicated by a delay and/or a retardation of degradation. The present paper considers the influence of the nature of the antioxidant (hindered phenols, aromatic amines, and organic compounds containing sulphur atoms) on the thermooxidative behaviour of a low density polyethylene at 200 deg C. The following characteristics have been measured in polymer samples with zero; 0.1; 0.5; and 1.0 wt% content of antioxidant: the induction time of the oxidation process, rate of autoxidation and rate of polymer degradation (up to about 20% weight loss). The difference in thermal stability in radiation crosslinked material and comparative retardation of the thermooxidative degradation is observed up to an absorbed dose of 200 kGy.

Polyethylene glycol without electrolytes for children with constipation and encopresis.

Science.gov (United States)

Loening-Baucke, Vera

2002-04-01

Children with functional constipation and encopresis benefit from behavior modification and from long-term laxative medication. Polyethylene glycol without electrolytes has become the first option for many pediatric gastroenterologists. Twenty-eight children treated with polyethylene glycol without electrolytes were compared with 21 children treated with milk of magnesia to evaluate the efficiency, acceptability, side effects, and treatment dosage of polyethylene glycol in long-term treatment of functional constipation and encopresis. Children were rated as "doing well," "improved," or "not doing well," depending on resolution of constipation and encopresis. At the 1-, 3-, 6-, and 12-month follow-ups, bowel movement frequency increased and soiling frequency decreased significantly in both groups. At the 1-month follow-up, children on polyethylene glycol were soiling more frequently (P encopresis.

Heating tubes of cross-linked polyethylene

International Nuclear Information System (INIS)

Knoeppler, H.; Hoffmann, M.

1981-01-01

Oxygen permeability of plastic tubes for floor heating systems was measured as a function of the reduced oxygen content of water in plastic tubes at a flow rate of 0.5 m/s and a temperature of 30 0 C and as a function of oxygen uptake of low-oxygen water in floor heating tubes. Pipes of VEP, periodically cross-linked polyethylene (Engels process), polypropylene copolymeride, and polybutene were compared. The permeability of periodically cross-linked polyethylene is twice as high as that of VEP. Measurements, results, and consequences for floor heating systems are discussed. (KH) [de

Degradation of polyethylene induced by plasma in oxidizing atmospheres

International Nuclear Information System (INIS)

Colin, E.; Olayo, M.G.; Cruz, G.J.

2002-01-01

The garbage of polyethylene is not easily degradable in normal environmental conditions . The indiscriminate use of this polymer and the enormous quantity of garbage which is generated carries a damage to the environment due to its long life as waste. The objective of this work is to study the conditions in which can be carried out the degradation of polyethylene. A form of accelerating the degradation is exposing it to plasma with reactive atmospheres. In this work a study of surface modification of polyethylene by plasmas with discharges of direct current of oxygen and nitrogen is presented. (Author)

Study on Ballistic Absorbing Energy Character of High Performance Polyethylene Needle Felt

Science.gov (United States)

Kailiang, Zhu; Jianqiao, Fu

2017-11-01

The ballistic performance of polyethylene needle felt is tested and the failure morphology after test is also observed. The results showed that when the non-dimensionally non-stressed fibers in polyethylene needles are subjected to high-speed projectile, secondary movement such as stretching and twisting occurs first. This secondary movement is very full, it is the main way of ballistic absorbing energy of the polyethylene needle felt which can avoid the polyethylene fiber short-term rapid heating-up and destroyed. Analysis results show that under normal temperature and humidity conditions, the V50 of 6-layer forded polyethylene needle felt sample is 250m/s. At (450 ± 50) m/s speed range of the target missile, the mean value of the penetrative specific energy absorption for 3-layer forded polyethylene needle felt anti-1.1g simulated projectiles (tapered column) reaches 24.1J·m2/kg.

Experimental study of co-pyrolysis of polyethylene/sawdust mixtures

Directory of Open Access Journals (Sweden)

Berrueco Cesar

2004-01-01

Full Text Available A study of the behavior of the thermal decomposition of mixtures of biomass and thermoplastics, such as polyethylene, is of interest for processes for the thermal recovery of industrial and urban wastes such as pyrolysis or gasification. No solid residue is formed during the thermal degradation of pure polyethylene. However, the addition of biomass, which generates char can vary the product distribution and increase the heating value of the gas obtained. A study of the thermal degradation of pine sawdust, polyethylene and mixtures of polyethylene and pine sawdust has been carried out in a fluidized bed reactor. Experiments were carried out at five different temperatures: 640, 685, 730, 780, and 850 ºC. The yields and composition of the derived oil, wax, and gas were determined. The addition of polyethylene increases the gas production and decreases the production of waxes and liquids for the different temperatures tested. The main gases produced from the co-pyrolysis process were, at low temperatures, carbon monoxide ethylene, carbon dioxide, propylene, butadiene, methane and pentadiene while at high temperatures the gas composition changed drastically, the main components being carbon monoxide (more than 33 wt.%, ethylene, methane benzene and hydrogen. The analysis of the liquid fraction shows a decrease of the concentration of oxygenated and aliphatic compounds.

Development of new cross-linked polyethylene for atomic energy

International Nuclear Information System (INIS)

Fujimura, Shun-ichi; Ohya, Shingo; Kubo, Masaji; Tsutsumi, Yukihiro; Seguchi, Tadao.

1988-01-01

Cross-linked polyethylene is the material which is used most as the insulating material for electric wires and cables, but for the cables for nuclear power stations and the wiring materials within machinery and equipment, the cross-linked polyethylene which is hard to burn by mixing burning-retarding agent is frequently used as the disaster-preventing countermeasures. As the burning-retarding agent for cross-linked polyethylene, bromine system agent that gives high burning retardation, chlorine system agent that can prevent melting and dripping at the time of burning and so on have been used so as to meet the objective. However by the addition of burning-retarding agents, the electrical and mechanical characteristics of cross-linked polyethylene lower, therefore consideration must be given to the use. In this paper, the results of the examination on the application of condensed acenaphthylene bromide as a new burning-retarding agent to cross-linked polyethylene are reported. White lead was effective for catching HBr. It was confirmed that more than 30 parts of this agent ensured burning retardation. By mixing this agent, the tensile strength increased, but the elongation lowered. It was found that the good radiation resistance was obtained by adding this agent. (K.I.)

Chemical and physical change of packaging materials for food by gamma-ray irradiation

International Nuclear Information System (INIS)

Kawamura, Yoko; Yamada, Takashi

1999-01-01

Recently, foods are often exposed to radiation under packed states with various wrapping materials. In this study, the effects of γ-ray radiation were investigated on the additives in wrapping materials on the market. 10 - 50 kGy γ radiation was irradiated to samples under sealed condition in a glass-ware. Polyethylene bag and wrapping film, polypropylene wrapping film, cup and sheet, and polystyrene cup were used as samples. And the additives in these materials were analyzed by GC/MS to evaluate the radiation effects on them. The irradiation was found to induce rapid degradation of antioxidants, especially, Irgafos 168. Some fatty acid amides used as a lubricant and a plasticizer, DBP were also reduced, but not aliphatic hydrocarbons. However, all polystyrene products used in this study included no additives. The contents of styrene dimer and trimer in those wrapping materials were not changed by γ-irradiation. (M.N.)

Seed germination of peanuts irradiated with cobalt ({sup 60}CO); Germinacao de sementes de amendoim irradiadas com cobalto ({sup 60}Co)

Energy Technology Data Exchange (ETDEWEB)

Alves, Niedja Marrize C.; Almeida, Francisco de Assis C.; Gomes, Josivanda P.; Pessoa, Elvira B., E-mail: niedjamarizze@yahoo.com.b, E-mail: josivanda@deag.ufcg.edu.b, E-mail: elvirabe@gmail.co [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia Agricola; Leal, Artur S. Cavalcanti, E-mail: arturcleal@yahoo.com.b [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais

2010-07-01

This work was realized to evaluate the effect of gamma irradiation ({sup 60}Co) at doses 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 and 4.00 kGy, on germination of seeds of peanut, cultivar BR1. Irradiation Department of Nuclear, UFPE, where he received after the irradiation, they were stored in packing of PET and polyethylene braided with a time of 90 days. Through the results, obtained monthly, concluded that the dose of 0.5 kGy was effective in the germination of seeds of peanut, not affecting its power of germination and overcoming the witness within 30 to 60 days. (author)

The influence of electron-beam irradiation on some mechanical properties of commercial multilayer flexible packaging materials (PET MET/LDPE)

International Nuclear Information System (INIS)

Nogueira, Beatriz R.; Oliveira, Vitor M.; Moura, Esperidiana A.B.; Ortiz, Angel V.

2009-01-01

The treatment with electron-beam radiation is a promising approach to the controllable modification of the properties of the polymeric flexible packaging materials, in order to adjust their properties. In recent years electron-beam irradiation have been efficiently applied in the flexible packaging industry to promote crosslinking and scission of the polymeric chains in order to improve material mechanical properties. On the other hand, ionizing irradiation can also affect the polymeric materials itself leading to a production of free radicals. These free radicals can in turn lead to degradation and or cross-linking phenomena. The influence of electron beam irradiation on mechanical properties of commercial multilayer flexible packaging materials based on laminated low-density polyethylene (LDPE) and metallized poly(ethylene terephthalate) (PET) was studied. The PETmet/LDPE structure was irradiated with doses up to 120 kGy, using a 1.5 MeV electron beam accelerator, dose rate 11.22kGy/s, at room temperature in presence of air. The results showed that penetration resistance of the irradiated PETmet/LDPE film increase up to 10 %, except for radiation dose of 30 kGy that resulted in a slight decrease of ca. 3%, while the sealing resistance decreased ca. 8-26% in all doses (p < 0.05). In addition, the samples of PETmet/LDPE film at 45, 60, 75 and 105 kGy presented a gain up to 18 % in their original tensile strength at break, a gain of ca. 38% in their original elongation at break for radiation dose of 45 kGy and ca. 17% for radiation doses of 60, 75 and 120 kGy. (author)

Aqueous polyethylene oxide solutions

International Nuclear Information System (INIS)

Breen, J.

1987-01-01

A number of aspects concerning the reorientation of polymer, water and ion hydration complexes have been studied in aqueous solution of polyethylene oxide (PEO). The polymer dynamics are investigated by 1 H-PEO and 13 C-PEO nuclear relaxation experiments. 162 refs.; 30 figs.; 19 tabs

Industrial irradiation

International Nuclear Information System (INIS)

Stirling, Andrew

1995-01-01

Production lines for rubber gloves would not appear to have much in common with particle physics laboratories, but they both use accelerators. Electron beam irradiation is often used in industry to improve the quality of manufactured goods or to reduce production cost. Products range from computer disks, shrink packaging, tyres, cables, and plastics to hot water pipes. Some products, such as medical goods, cosmetics and certain foodstuffs, are sterilized in this way. In electron beam irradiation, electrons penetrate materials creating showers of low energy electrons. After many collisions these electrons have the correct energy to create chemically active sites. They may either break molecular bonds or activate a site which promotes a new chemical linkage. This industrial irradiation can be exploited in three ways: breaking down a biological molecule usually renders it useless and kills the organism; breaking an organic molecule can change its toxicity or function; and crosslinking a polymer can strengthen it. In addition to traditional gamma irradiation using isotopes, industrial irradiation uses three accelerator configurations, each type defining an energy range, and consequently the electron penetration depth. For energies up to 750 kV, the accelerator consists of a DC potential applied to a simple wire anode and the electrons extracted through a slot in a coaxially mounted cylindrical cathode. In the 1-5 MeV range, the Cockcroft-Walton or Dynamitron( R ) accelerators are normally used. To achieve the high potentials in these DC accelerators, insulating SF6 gas and large dimension vessels separate the anode and cathode; proprietary techniques distinguish the various commercial models available. Above 5 MeV, the size of DC accelerators render them impractical, and more compact radiofrequency-driven linear accelerators are used. Irradiation electron beams are actually 'sprayed' over the product using a magnetic deflection system. Lower energy beams of

Preparation of reinforced poly(ethylene oxide) blend hydrogel films containing a drug and assessment of their properties

International Nuclear Information System (INIS)

Yang Zhanshan; Zhu Nankang; Yang Shuqin

1999-01-01

Reinforced poly(ethylene oxide) blend hydrogen films containing mafenide acetate were prepared by using two freezing-thawing cycles and the irradiation crosslinking technique, and their properties and the drug release were assessed. The results showed that the tensile strength of the reinforced PEO blend hydrogel films increased significantly (p < 0.01), the gel fraction and the elongation at break of the films increased slightly as compared with those formed by the irradiation without the freezing-thawing treatment, indicating that the mechanical properties of the PEO blend hydrogel films can be improved by the freezing-thawing cycles. The reinforced films possessed an ideal flexibility, crosslinking density and elasticity as wound dressings. Swelling studies showed that the equilibrium water content of the hydrogel films expressed in the degree of swelling decreased significantly (p < 0.01), suggesting that a significant structural rearrangement of the films occurred during the freezing process. The structural densification resulted in the increase of the mechanical strength of the hydrogel films. The hydrogels formed by the irradiation at doses of 40 kGy were comparatively stronger. Release studies were run on the reinforced hydrogels with mafenide acetate which was incorporated before the freezing-thawing treatment. Release was followed over seven days. The drug transport was controlled by a regular diffusion model

Influence of irradiation on the degradation speed of pre servants of sliced pineapple preserved by a combined method

International Nuclear Information System (INIS)

Garcia A, A.; Castro, D.; Espinosa, R.; Gonzalez, E.; Fernandez, L.; Garcia R, M.O.

1995-01-01

In the fulfillment of this study, pineapple of the spanish red variety, cut in 1.0 - 1.5 cm slices, were used. The product was sunken in a saccharose syrup with the addition of sodium methabisulphite and potassium sorbate and packed in polyethylene bags and latter irradiated with 0.2 and KGy doses. The behavior of potassium sorbate with two addition levels is similar during storage at room temperature for the studied irradiation doses. The degradation process of sodium methabisulphite takes place almost totally at one month storage. Unlike of potassium sorbate there exist no meaning differences between sulfur dioxide in irradiated and nonirradiated samples.It is concluded that the irradiation process cause an increasing in the degradation of potassium sorbate basically at the beginning of the storage, while seems no exert some effect on the sodium methabisulphite degradation. (Author)

Polyethylene glycol as a promising synthetic material for repair of spinal cord injury

Directory of Open Access Journals (Sweden)

Xian-bin Kong

2017-01-01

Full Text Available Polyethylene glycol is a synthetic, biodegradable, and water-soluble polyether. Owing to its good biological and material properties, polyethylene glycol shows promise in spinal cord tissue engineering applications. Although studies have examined repairing spinal cord injury with polyethylene glycol, these compelling findings have not been recently reviewed or evaluated as a whole. Thus, we herein review and summarize the findings of studies conducted both within and beyond China that have examined the repair of spinal cord injury using polyethylene glycol. The following summarizes the results of studies using polyethylene glycol alone as well as coupled with polymers or hydrogels: (1 polyethylene glycol as an adjustable biomolecule carrier resists nerve fiber degeneration, reduces the inflammatory response, inhibits vacuole and scar formation, and protects nerve membranes in the acute stage of spinal cord injury. (2 Polyethylene glycol-coupled polymers not only promote angiogenesis but also carry drugs or bioactive molecules to the injury site. Because such polymers cross both the blood-spinal cord and blood-brain barriers, they have been widely used as drug carriers. (3 Polyethylene glycol hydrogels have been used as supporting substrates for the growth of stem cells after injury, inducing cell migration, proliferation, and differentiation. Simultaneously, polyethylene glycol hydrogels isolate or reduce local glial scar invasion, promote and guide axonal regeneration, cross the transplanted area, and re-establish synaptic connections with target tissue, thereby promoting spinal cord repair. On the basis of the reviewed studies, we conclude that polyethylene glycol is a promising synthetic material for use in the repair of spinal cord injury

Polyethylene glycol as a promising synthetic material for repair of spinal cord injury

Institute of Scientific and Technical Information of China (English)

Xian-bin Kong; Qiu-yan Tang; Xu-yi Chen; Yue Tu; Shi-zhong Sun; Zhong-lei Sun

2017-01-01

Polyethylene glycol is a synthetic, biodegradable, and water-soluble polyether. Owing to its good biological and material properties, polyethylene glycol shows promise in spinal cord tissue engineering applications. Although studies have examined repairing spinal cord injury with polyethylene glycol, these compellingfindings have not been recently reviewed or evaluated as a whole. Thus, we herein review and summarize the findings of studies conducted both within and beyond China that have examined the repair of spinal cord injury using polyethylene glycol. The following summarizes the results of studies using polyethylene glycol alone as well as coupled with polymers or hydrogels: (1) polyethylene glycol as an adjustable bio-molecule carrier resists nerve fiber degeneration, reduces the inflammatory response, inhibits vacuole and scar formation, and protects nerve membranes in the acute stage of spinal cord injury. (2) Polyethylene glycol-coupled polymers not only promote angiogenesis but also carry drugs or bioactive molecules to the injury site. Because such polymers cross both the blood-spinal cord and blood-brain barriers, they have been widely used as drug carriers. (3) Polyethylene glycol hydrogels have been used as supporting sub-strates for the growth of stem cells after injury, inducing cell migration, proliferation, and differentiation. Simultaneously, polyethylene glycol hydrogels isolate or reduce local glial scar invasion, promote and guide axonal regeneration, cross the transplanted area, and re-establish synaptic connections with target tissue, thereby promoting spinal cord repair. On the basis of the reviewed studies, we conclude that polyethylene glycol is a promising synthetic material for use in the repair of spinal cord injury.

Adsorption of anionic surfactant on porous and nonporous polyethylene terephthalate films

International Nuclear Information System (INIS)

Yamauchi, Yu.; Apel, P.Yu.

2016-01-01

We study the adsorption of anionic surfactant, sodium dodecyl diphenyloxide disulfonate (SDDD) on three types of polyethylene terephthalate (PET) substrates from aqueous solutions of SDDD of different concentrations. Neutral electrolyte (KCl) was added to the solutions to vary the ionic strength. Three types of substrates were used: 1) original PET film; 2) etched nonporous film, obtained from pristine film by chemical etching and bearing negative charge on the surface; 3) etched porous membranes, fabricated from pristine film by ion irradiation and subsequent chemical etching. The membranes have negative charge on the flat surface and on the inner pore walls. The comparison shows that the negative charge on the flat surface has weak effect on adsorption of the anionic surfactant, and the SDDD adsorption on the inner walls of pores is much weaker than on flat surface, even if the pore radius is significantly larger than the Debye length. This «exclusion» effect strongly depends on ionic strength of solution. [ru

Influence of different kinds of ionizing irradiations on polymer properties. Radiational electroconductivity

International Nuclear Information System (INIS)

Tyutnev, A.P.; Sichkar', V.P.; Boev, S.G.

1991-01-01

Comparative analysis of induced electric conductivity (IE) of low-density polyethylene and polystyrene in the process of their continuous irradiation by 60 Co gamma-radiation, accelerated protons (7.7 MeV) and alpha-particles (20 MeV) was carried out. It was shown that in the series a regular decrease in IE of the polymers per dose rate unity was observed, which was related to the growth of bast track losses for recombination prior to charge entrance to the polymer volume

Phase behaviour of polyethylene knotted ring chains

International Nuclear Information System (INIS)

Wen Xiao-Hui; Xia A-Gen; Chen Hong-Ping; Zhang Lin-Xi

2011-01-01

The phase behaviour of polyethylene knotted ring chains is investigated by using molecular dynamics simulations. In this paper, we focus on the collapse of the polyethylene knotted ring chain, and also present the results of linear and ring chains for comparison. At high temperatures, a fully extensive knot structure is observed. The mean-square radius of gyration per bond (S 2 )/(Nb 2 ) and the shape factor (δ*) depend on not only the chain length but also the knot type. With temperature decreasing, chain collapse is observed, and the collapse temperature decreases with the chain length increasing. The actual collapse transition can be determined by the specific heat capacity C v , and the knotted ring chain undergoes gas—liquid—solid-like transition directly. The phase transition of a knotted ring chain is only one-stage collapse, which is different from the polyethylene linear and ring chains. This investigation can provide some insights into the statistical properties of knotted polymer chains. (condensed matter: structural, mechanical, and thermal properties)

Mechanical, Rheological, and Bioactivity Properties of Ultra High-Molecular-Weight Polyethylene Bioactive Composites Containing Polyethylene Glycol and Hydroxyapatite

Directory of Open Access Journals (Sweden)

Mazatusziha Ahmad

2012-01-01

Full Text Available Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P precipitates on the composite surface as proven from SEM and XRD analysis.

Colored polyethylene soil covers and grafting effects on cucumber flowering and yield

Directory of Open Access Journals (Sweden)

Fonseca Inês Cristina de Batista

2003-01-01

Full Text Available Cucumber (Cucumis sativus L. is one of the most cultivated vegetable crops in plastic greenhouses in Brazil because of the short cycle and its high economic value in off-season harvests. To better understand this management technique the effect of different colored polyethylene soil covers was evaluated in relation to flowering and yield of the hybrid cucumber 'Yoshinari' grafted or not on the hybrid squash 'Ikky'. The polyethylene cover colors were black, white on black and green plus a control without cover. Covered but not grafted crops had a more uniform flowering distribution. The number of flowers was greater for the white/black grafted treatment. All the polyethylene covers favored flowering for the non grafted plants. Grafting reduced flowering for the black or green polyethylene covers treatments. The fruit set increased with the use of polyethylene cover but was not influenced by grafting. The uniform distribution of flowering remained during fruiting only for grafted plants and soil covered with black or green polyethylene. Both polyethylene cover and grafting favored early harvesting. The 'Yoshinari'/'Ikky' graft caused taller plants but fruit were thicker and smaller and did not meet the commercial standard. The best quality fruit and highest yields were obtained in the black and white/black treatments, without grafting.

Results of preliminary experiments on tritium decontamination by UV irradiation

International Nuclear Information System (INIS)

Oya, Yasuhisa; Shu, Wataru; O'hira, Shigeru; Hayashi, Takumi; Nishi, Masataka

2000-03-01

In the point of view of protection of workers from the radiation exposure and the limitation of the contamination with radioactive materials, it is important to decontaminate mobile tritium from plasma facing components of a nuclear fusion reactor at the beginning of their maintenance work. It is considered that the heating is the most effective method for decontamination. However, it is important to develop new decontamination method of adsorbed hydro-carbon based substances from the materials that cannot be heated or the inner pipe of double pipes. This report presents results of preliminary experiments performed for the development of the effective tritium decontamination technique pursuing under US/Japan collaborative program on technology for fusion-fuel processing (Annex IV). In the experiments, the effects of Ultra Violet (UV) irradiation on tritium removal from some kinds of materials, such as poly vinyl chloride -(CH 2 CHCl) n - film, polyethylene film and graphite samples coated by C 2 H 2 plasma were examined. As the result of UV irradiation, it was confined that hydrogen and carbon based compounds could be released from the specimen during UV irradiation. It is concluded that UV irradiation is one of the hopeful candidates for effective tritium decontamination. (author)

An Investigation on Rheology of Peroxide Cross-linking of Low Density Polyethylene

DEFF Research Database (Denmark)

Ghasemi, Ismaeil; Rasmussen, Henrik K.; Szabo, Peter

2005-01-01

One of the most important post-reactor modifications of polyethylene is cross-linking. It improves some properties of polyethylene such as environmental stress cracking resistance, chemical and abrasion resistance, and service temperature. In this study, the effect of peroxide cross-linking on th......One of the most important post-reactor modifications of polyethylene is cross-linking. It improves some properties of polyethylene such as environmental stress cracking resistance, chemical and abrasion resistance, and service temperature. In this study, the effect of peroxide cross......-linking on the rheological behaviour of low density polyethylene was investigated by using a combination of creep test and differential scanning calorimeter (DSC) in isotherm condition. The used peroxide was di-cumyl peroxide and its concentration was 2 wt%. The experiments were carried out at 150,160, and 170 degrees C...

Relationship between product demand, tibial polyethylene insert shelf age, and total knee arthroplasty survival: retrospective review of total knees of one design.

Science.gov (United States)

Urban, Joshua A; Collier, Matthew B; Engh, C Anderson; Engh, Gerard A

2006-04-01

Shelf aging of gamma-irradiated-in-air polyethylene tibial components has been associated with increased articular surface wear and an elevated risk for revision. Nine hundred fifty cruciate-retaining inserts of one design were implanted between 1987 and 1996 (shelf age, 1.0 +/- 1.2 years). Less frequently used inserts (smallest/largest sizes, thicker thicknesses, supplemental articular constraint) had longer shelf ages (means ranged from 1.2 to 2.6 years). Survival analysis showed that shelf age (P product demand and can be of aid when diagnosing the painful knee.

Characterization of polymeric films subjected to lithium ion beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Groenewold, Gary S., E-mail: gary.groenewold@inl.gov [Idaho National Laboratory, 2351 North Boulevard, Idaho Falls, ID 83415-2208 (United States); Cannon, W. Roger; Lessing, Paul A. [Idaho National Laboratory, 2351 North Boulevard, Idaho Falls, ID 83415-2208 (United States); Avci, Recep; Deliorman, Muhammedin; Wolfenden, Mark [Image and Chemical Analysis Laboratory, Montana State University, Bozeman, MT 59717 (United States); Akers, Doug W.; Jewell, J. Keith; Zuck, Larry D. [Idaho National Laboratory, 2351 North Boulevard, Idaho Falls, ID 83415-2208 (United States)

2013-02-01

Highlights: ► Polyethylene glycol (PEG) and paraffinic polymers were subjected to Li ion irradiation. ► Small oligomers detected in irradiated PEG by electrospray ionization (ESI) mass spectrometry. ► Radiolytic scission observed in X-ray photoelectron and electrospray ionization mass spectra. ► Radiation modified paraffinics characterized by changes in non-ionic surfactant additives. ► Results suggest that extent of radiolysis, and radiolytic pathways can be inferred. -- Abstract: Two different polymeric materials that are candidate materials for use as binders for mixed uranium–plutonium oxide nuclear fuel pellets were subjected to Li ion beam irradiation, in order to simulate intense alpha irradiation. The materials (a polyethylene glycol 8000 and a microcrystalline wax) were then analyzed using a combination of mass spectrometry (MS) approaches and X-ray photoelectron spectroscopy (XPS). Samples of the irradiated PEG materials were dissolved in H{sub 2}O and then analyzed using electrospray ionization-MS, which showed the formation of a series of small oligomers in addition to intact large PEG oligomers. The small oligomers were likely formed by radiation-induced homolytic scissions of the C–O and C–C bonds, which furnish radical intermediates that react by radical recombination with H{sup ·} and OH{sup ·}. Surface analysis using SIMS revealed a heterogeneous surface that contained not only PEG-derived polymers, but also hydrocarbon-based entities that are likely surface contaminants. XPS of the irradiated PEG samples indicated the emergence of different carbon species, with peak shifts suggesting the presence of sp{sup 2} carbon atoms. Analysis of the paraffinic film using XPS showed the emergence of oxygen on the surface of the sample, and also a broadening and shifting of the C1s peak, demonstrating a change in the chemistry on the surface. The paraffinic film did not dissolve in either H{sub 2}O or a H{sub 2}O–methanol solution, and

All-Polyethylene Tibial Components: An Analysis of Long-Term Outcomes and Infection.

Science.gov (United States)

Houdek, Matthew T; Wagner, Eric R; Wyles, Cody C; Watts, Chad D; Cass, Joseph R; Trousdale, Robert T

2016-07-01

There is debate regarding tibial component modularity and composition in total knee arthroplasty (TKA). Biomechanical studies have suggested improved stress distribution in metal-backed tibias; however, these results have not translated clinically. The purpose of this study was to analyze the outcomes of all-polyethylene components and to compare the results to those with metal-backed components. We reviewed 31,939 patients undergoing a primary TKA over a 43-year period (1970-2013). There were 28,224 (88%) metal-backed and 3715 (12%) all-polyethylene tibial components. The metal-backed and all-polyethylene groups had comparable demographics with respect to gender, age and body mass index (BMI). Mean follow-up was 7 years. The mean survival for all primary TKAs at the 5-, 10-, 20- and 30-year time points was 95%, 89%, 73%, and 57%, respectively. All-polyethylene tibial components were found to have a significantly improved (P tibial components were also found to have a significantly lower rate of infection, instability, tibial component loosening, and periprosthetic fracture. The all-polyethylene group had improved survival rates in all age groups, except in patients 85 years old or greater, where there was no significant difference. All-polyethylene tibial components had improved survival for all BMI groups except in the morbidly obese (BMI ≥ 40) where there was no significant difference. All-polyethylene tibial components had significantly improved implant survival, reduced rates of postoperative infection, fracture, and tibial component loosening. All polyethylene should be considered for most of the patients, regardless of age and BMI. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of compensating filters on the isodose charts of rat and guinea-pig phantoms irradiated with ''fission-neutrons''

Energy Technology Data Exchange (ETDEWEB)

Zar' and, P

1976-01-01

Isodose charts were calculated for rat and guinea-pig phantoms exposed to a modified fission spectrum with a most probable energy of 1.3 MeV. Infinite tissue equivalent cylinders (r = 2.5 and 3.3 cm) and a plane source emitting neutrons according to a cosine distribution were assumed and an albedo code was used. Combined effect of (tissue-equivalent or polyethylene) compensating filters (or simply filters) and a bilateral irradiation or rotation was studied. Bilateral irradiation and the use of a filter resulted in a uniform irradiation of a rat phantom (Dmax/Dmin less than 1.15), while a uniform irradiation of a guinea-pig phantom could be obtained by the combined use of filters and rotation. If rotation is possible a Dmax/Dmin less than 1.05 ratio can be achieved. Filters + rotation should be used in all circumstances when geometrical restrictions do not prevent the installation of a rotation equipment. In this case bilateral irradiation + compensating filters are advisable. Unilateral irradiation of small laboratory animals (mouse, rat, guinea-pig) should be avoided.

The effect of gamma radiation on hardness evolution in high density polyethylene at elevated temperatures

International Nuclear Information System (INIS)

Chen, Pei-Yun; Chen, C.C.; Harmon, Julie P.; Lee, Sanboh

2014-01-01

This research focuses on characterizing hardness evolution in irradiated high density polyethylene (HDPE) at elevated temperatures. Hardness increases with increasing gamma ray dose, annealing temperature and annealing time. The hardness change is attributed to the variation of defects in microstructure and molecular structure. The kinetics of defects that control the hardness are assumed to follow the first order structure relaxation. The experimental data are in good agreement with the predicted model. The rate constant follows the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The defects that control hardness in post-annealed HDPE increase with increasing dose and annealing temperature. The structure relaxation of HDPE has a lower energy of mixing in crystalline regions than in amorphous regions. Further, the energy of mixing for defects that influence hardness in HDPE is lower than those observed in polycarbonate (PC), poly(methyl methacrylate) (PMMA) and poly (hydroxyethyl methacrylate) (HEMA). This is due to the fact that polyethylene is a semi-crystalline material, while PC, PMMA and PHEMA are amorphous. - Highlights: • Hardness of HDPE increases with increasing gamma ray dose, annealing time and temperature. • The hardness change arises from defects in microstructure and molecular structure. • Defects affecting hardness follow a kinetics of structure relaxation. • The structure relaxation has a low energy of mixing in crystalline regime

The effect of gamma radiation on hardness evolution in high density polyethylene at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Chen, Pei-Yun [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chen, C.C. [Institute of Nuclear Energy Research, Longtan, Taoyuan 325, Taiwan (China); Harmon, Julie P. [Department of Chemistry, University of South Florida, Tampa, FL 33620 (United States); Lee, Sanboh, E-mail: sblee@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China)

2014-08-01

This research focuses on characterizing hardness evolution in irradiated high density polyethylene (HDPE) at elevated temperatures. Hardness increases with increasing gamma ray dose, annealing temperature and annealing time. The hardness change is attributed to the variation of defects in microstructure and molecular structure. The kinetics of defects that control the hardness are assumed to follow the first order structure relaxation. The experimental data are in good agreement with the predicted model. The rate constant follows the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The defects that control hardness in post-annealed HDPE increase with increasing dose and annealing temperature. The structure relaxation of HDPE has a lower energy of mixing in crystalline regions than in amorphous regions. Further, the energy of mixing for defects that influence hardness in HDPE is lower than those observed in polycarbonate (PC), poly(methyl methacrylate) (PMMA) and poly (hydroxyethyl methacrylate) (HEMA). This is due to the fact that polyethylene is a semi-crystalline material, while PC, PMMA and PHEMA are amorphous. - Highlights: • Hardness of HDPE increases with increasing gamma ray dose, annealing time and temperature. • The hardness change arises from defects in microstructure and molecular structure. • Defects affecting hardness follow a kinetics of structure relaxation. • The structure relaxation has a low energy of mixing in crystalline regime.

Investigation of properties of (U)HMW-PE under the influence of gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Ehe, K. von der; Wolff, D.; Boehning, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany)

2012-11-01

High molecular weight polyethylene (HMW-PE) and ultra high molecular weight polyethylene (UHMW-PE) are high performance materials, which are predestinated for a wide range of applications due to characteristics like high chemical resistance, low wear, and high hydrogen content. In addition to the application of (U)HMW-PE as sports equipment (sliding surface of snowboards, skis) and in mechanical engineering (materials for spur gears and chain guides) these polymers are used in two other and even more demanding areas: as implant material in medical technology and as a component for neutron shielding purposes in casks for storage and transport of radioactive waste. In these two cases, gamma irradiation and its impact on the molecular structure of polyethylene play an important role. In the first case, irradiation is applied for sterilization purposes and in the second one it exists as a side-effect of inserting the radioactive material in the cask. Specifically concerning their use in the field of medical technology, different types of UHMW-PE have been intensively studied. It is generally accepted that two concurrent and competitive processes, based on initial chain scission and subsequent reactions of C-centered radicals and molecular fragments, occur in PE as a consequence of radiation: radical recombination accounts for crosslinking, together with some disproportionation, formation of low molecular weight fragments, and recrystallization. Furthermore, formation of oxygenated structures in the presence of traces of oxygen is a competitive process to those mentioned above. Radiation induced scission preferentially takes place in the amorphous phase and noncrystalline surface of the crystallites and results in shorter polymer chains, fewer entanglements, and consequently, increased molecular mobility. The latter enables folding of polymer segments and thus, crystal growth and increased perfection in the crystal lamellae. With regard to the long-term application of

Physico-chemical and mechanical modifications of polyethylene and polypropylene by ion implantation, micro-wave plasma, electron beam radiation and gamma ray irradiation; Modifications physico-chimiques et mecaniques du polyethylene et du polypropylene par implantation ionique, plasma micro-ondes, bombardement d`electrons et irradiation gamma

Energy Technology Data Exchange (ETDEWEB)

Liao, J D

1995-03-29

A polyolefin surface becomes wettable when treated by micro-wave plasma or low-dose nitrogen ion implantation. A short time argon plasma treatment is sufficient to obtain polarizable peroxides on a polyolefin. X-ray photoelectron spectroscopy analyses, paramagnetic electronic resonance analyses, peroxides decomposition, wettability measurements and infrared active spectra analyses have shown that oxidized structures obtained from different treatment techniques play an important role in the interpretation of surface chemical properties of the polymer. Micro-wave plasma treatment, and in particular argon plasma treatment, yields more polarizable groups than ion implantation and is interesting for grafting. Hardness and elasticity modulus, measured by nano-indentation on a polyolefin, increase with an appropriate ion implantation dose. A 1.4 x 10{sup 17} ions.cm{sup -2} dose can multiply by 15 the hardness of high molecular weight polyethylene, and by 7 the elasticity modulus for a 30 nm depth. The viscous-plastic to quasi-elastic transition is shown. The thickness of the modified layer is over 300 nm. The study of friction between a metal sphere and a polyethylene cupula shows that ion implantation in the polymer creates a reticulated hard and elastic layer which improves its mechanical properties and reduces the erosion rate. Surface treatments on polymers used as biomaterials allow to adapt the surface properties to specific applications. 107 refs., 66 figs., 19 tabs., 4 annexes.

Solid polymer electrolyte on the basis of polyethylene carbonate-lithium perchlorate system

International Nuclear Information System (INIS)

Dukhanin, G.P.; Dumler, S.A.; Sablin, A.N.; Novakov, I.A.

2009-01-01

Reaction in the system polyethylene carbonate-lithium perchlorate was investigated by IR spectroscopy, differential thermal and X-ray structural analyses. Specific electric conductivity of the prepared composition has been measured. Solid polymer electrolytes on the basis of polyethylene carbonate have conducting properties as electrolytes on the basis of unmodified polyethylene oxide. Compositions of polyethylene carbonate : LiClO 4 =10 : 1Al 2 O 3 -ZrO 2 possess maximum value of electrical conductivity. Activation energies of the process is calculated for all investigated compositions, and dependence of these values from concentration of lithium perchlorate is established

Structural changes in the polyethylene after ion implantation

International Nuclear Information System (INIS)

Proskova, K.; Svorcik, V.

1999-01-01

This work deals with the study of structural changes of the polyethylene after ion implantation. There were used the polyethylene film with thickness 15 μm, and Ar + ions with energy 63 keV and Xe + ions with energy 156 keV with doses 1·10 13 - 3·10 15 cm -2 for experiments. For the study of structural changes of polymer were used methods UV-VIS spectrometry, ESR, Rutherford back scattering

Transdermal thiol-acrylate polyethylene glycol hydrogel synthesis using near infrared light

Science.gov (United States)

Chung, Solchan; Lee, Hwangjae; Kim, Hyung-Seok; Kim, Min-Gon; Lee, Luke P.; Lee, Jae Young

2016-07-01

Light-induced polymerization has been widely applied for hydrogel synthesis, which conventionally involves the use of ultraviolet or visible light to activate a photoinitiator for polymerization. However, with these light sources, transdermal gelation is not efficient and feasible due to their substantial interactions with biological systems, and thus a high power is required. In this study, we used biocompatible and tissue-penetrating near infrared (NIR) light to remotely trigger a thiol-acrylate reaction for efficient in vivo gelation with good controllability. Our gelation system includes gold nanorods as a photothermal agent, a thermal initiator, diacrylate polyethylene glycol (PEG), and thiolated PEG. Irradiation with a low-power NIR laser (0.3 W cm-2) could induce gelation via a mixed-mode reaction with a small increase in temperature (~5 °C) under the optimized conditions. We also achieved successful transdermal gelation via the NIR-assisted photothermal thiol-acryl reactions. This new type of NIR-assisted thiol-acrylate polymerization provides new opportunities for in situ hydrogel formation for injectable hydrogels and delivery of drugs/cells for various biomedical applications.Light-induced polymerization has been widely applied for hydrogel synthesis, which conventionally involves the use of ultraviolet or visible light to activate a photoinitiator for polymerization. However, with these light sources, transdermal gelation is not efficient and feasible due to their substantial interactions with biological systems, and thus a high power is required. In this study, we used biocompatible and tissue-penetrating near infrared (NIR) light to remotely trigger a thiol-acrylate reaction for efficient in vivo gelation with good controllability. Our gelation system includes gold nanorods as a photothermal agent, a thermal initiator, diacrylate polyethylene glycol (PEG), and thiolated PEG. Irradiation with a low-power NIR laser (0.3 W cm-2) could induce gelation

Quality changes in irradiated and nonirradiated boiled-dried anchovies after inter-country transportation and storage at 25degC

International Nuclear Information System (INIS)

Kwon, J.H.; Byun, M.W.; Warrier, S.B.; Kamat, A.S.; Alur, M.D.; Nair, P.M.

1993-01-01

Samples of nonirradiated and irradiated (5 kGy) dried anchovies (Engraulis encrasicholus) were transported from Korea to India for evaluation of microbiological, physico-chemical and organoleptic parameters during storage. The nonirradiated anchovies showed mould growth and an increase in total bacterial count by three log cycles over the initial load, after four months of storage at 25degC. However, 5 kGy irradiated samples packed with a laminated nylon/polyethylene (NY/PE) film exhibited 10 2 bacterial cells per g even after 6 months storage. Hunter's colour value, total volatile basic nitrogen, browning and lipid oxidation showed a good correlation with the organoleptic quality of stored anchovies. Partial changes in irradiated anchovies did not influence organoleptic acceptability. Differences in the levels of total volatile basic nitrogen and total volatile acid values in irradiated and nonirradiated samples may prove useful in distinguishing irradiated Korean anchovies from nonirradiated samples. (author). 24 refs., 2 tabs., 1 fig

OBT analysis method using polyethylene beads for limited quantities of animal tissue

International Nuclear Information System (INIS)

Kim, S.B.; Stuart, M.

2015-01-01

This study presents a polyethylene beads method for OBT determination in animal tissues and animal products for cases where the amount of water recovered by combustion is limited by sample size or quantity. In the method, the amount of water recovered after combustion is enhanced by adding tritium-free polyethylene beads to the sample prior to combustion in an oxygen bomb. The method reduces process time by allowing the combustion water to be easily collected with a pipette. Sufficient water recovery was achieved using the polyethylene beads method when 2 g of dry animal tissue or animal product were combusted with 2 g of polyethylene beads. Correction factors, which account for the dilution due to the combustion water of the beads, are provided for beef, chicken, pork, fish and clams, as well as egg, milk and cheese. The method was tested by comparing its OBT results with those of the conventional method using animal samples collected on the Chalk River Laboratories (CRL) site. The results determined that the polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used. - Highlights: • Polyethylene beads method for OBT determination in animal tissues and animal products were determined. • The method reduces process time. • The polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used

Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice

NARCIS (Netherlands)

Willige, van R.W.G.; Linssen, J.P.H.; Legger, A.; Voragen, A.G.J.

2003-01-01

The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic

Keeping carrots quality during storage by irradiation

International Nuclear Information System (INIS)

El-Nashaby, F.M.; Hafez, S.A.

2000-01-01

Fresh carrots were gamma irradiated at 0, 0.1, 0.2, 0.5 and 1.0 KGy doses using cobalt-60 source. A portion of the irradiated carrots was stored at ambient temperature (20-25 degree C) and the rest was packed in polyethylene bags and stored in refrigerator temperature (5± 1 degree C). The results indicated that the sprouting of carrots were completely inhibited by radiation dose of 0.2 KGy either at ambient temperature or cold storage, while the non-irradiated samples started to sprout after 2 and 4 weeks of storage at ambient temperature and cold storage respectively. Furthermore, samples treated with gamma rays showed lower values of weight loss compared to the untreated ones during storage. Concerning storage temperature, it was found that the rate of weight loss during storage was higher at ambient temperature than in refrigerator. Micro-organisms were greatly affected by gamma rays, their counts were found to be decreased by increasing irradiation dose as compared with the control sample. Moreover, during storage period, refrigerated samples showed lower bacterial and molds counts than samples stored at ambient temperature. On the other hand, it was also observed that irradiated samples at the higher dose i.e. 1.0 KGy stored either at ambient temperature or in refrigerator showed higher bacterial and molds counts than unirradiated ones. The lowest dose (0.1 KGy) had no effect on carotene and sugars contents of carrots while increasing the dose above 0.2 KGy led to gradual decrease in carotene contents and gradual increase in total soluble sugars contents of the samples with increasing the irradiation dose compared with the nonirradiated ones. The results proved that gamma irradiation dose of 0.2 Gy was effective for sprout inhibition of carrots and increase their shelf-life to 10 weeks at ambient temperature without adverse effects on carotene and sugars contents of treated carrots

Well-Defined Bilayered Molecular Cobrushes with Internal Polyethylene Blocks and ω-Hydroxyl-Functionalized Polyethylene Homobrushes

KAUST Repository

Zhang, Hefeng

2016-02-15

Novel well-defined bilayered molecular cobrushes with internal polyethylene blocks, P(PEcore-b-PScorona) (PE: polyethylene; PS: polystyrene), and ω-hydroxyl-functionalized polyethylene homobrushes, P(PE-OH), were synthesized through the macromonomer strategy. Two main steps were involved in the synthesis of the P(PEcore-b-PScorona) bilayered cobrushes: (i) formation of norbornyl-terminated macromonomer (Nor-PE-b-PS) by esterification of PS-b-PE-OH (combination of anionic polymerization, hydroboration, and polyhomologation) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis polymerization (ROMP) of Nor-PE-b-PS. The synthesis of P(PE-OH) was achieved by (i) hydroboration of tert-butyldimethylsilyl-protected allyl alcohol, followed by polyhomologation of dimethylsulfoxoniun methylide with the formed tri[3-(tert-butyldimethylsilyloxyl)propyl]borane initiator, oxidation/hydrolysis, and esterification of the TBDMS-O-PE-OH with 5-norbornene-2-carboxylic acid to afford the macromonomer TBDMS-O-PE-Nor, and (ii) ROMP of TBDMS-O-PE-Nor, followed by deprotection. Nuclear magnetic resonance spectroscopy (1H and 13C NMR) and high temperature gel permeation chromatography (HT-GPC) were used to characterize all macromonomers/molecular brushes and differential scanning calorimetry (DSC) to study the thermal properties. The molecular brush P(PE-b-PS) showed lower melting point (Tm) and better solubility in toluene than the corresponding macromonomer PS-b-PE-Nor. In the case of homobrushes, the thermal properties were strongly affected by the presence of the PE end-groups. © 2016 American Chemical Society.

Well-Defined Bilayered Molecular Cobrushes with Internal Polyethylene Blocks and ω-Hydroxyl-Functionalized Polyethylene Homobrushes

KAUST Repository

Zhang, Hefeng; Hadjichristidis, Nikolaos

2016-01-01

Novel well-defined bilayered molecular cobrushes with internal polyethylene blocks, P(PEcore-b-PScorona) (PE: polyethylene; PS: polystyrene), and ω-hydroxyl-functionalized polyethylene homobrushes, P(PE-OH), were synthesized through the macromonomer strategy. Two main steps were involved in the synthesis of the P(PEcore-b-PScorona) bilayered cobrushes: (i) formation of norbornyl-terminated macromonomer (Nor-PE-b-PS) by esterification of PS-b-PE-OH (combination of anionic polymerization, hydroboration, and polyhomologation) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis polymerization (ROMP) of Nor-PE-b-PS. The synthesis of P(PE-OH) was achieved by (i) hydroboration of tert-butyldimethylsilyl-protected allyl alcohol, followed by polyhomologation of dimethylsulfoxoniun methylide with the formed tri[3-(tert-butyldimethylsilyloxyl)propyl]borane initiator, oxidation/hydrolysis, and esterification of the TBDMS-O-PE-OH with 5-norbornene-2-carboxylic acid to afford the macromonomer TBDMS-O-PE-Nor, and (ii) ROMP of TBDMS-O-PE-Nor, followed by deprotection. Nuclear magnetic resonance spectroscopy (1H and 13C NMR) and high temperature gel permeation chromatography (HT-GPC) were used to characterize all macromonomers/molecular brushes and differential scanning calorimetry (DSC) to study the thermal properties. The molecular brush P(PE-b-PS) showed lower melting point (Tm) and better solubility in toluene than the corresponding macromonomer PS-b-PE-Nor. In the case of homobrushes, the thermal properties were strongly affected by the presence of the PE end-groups. © 2016 American Chemical Society.

Effect of Gamma Irradiation on Blends Based on Thermoset or Thermoplast Polymers for Using in Some Useful Applications

International Nuclear Information System (INIS)

EMAN MOHAMED SHEHATA, E.M.

2013-01-01

Modification of polymers via blending and gamma irradiation crosslinking opens the door for solving many industrial problems and broad the application and markets for the products of modified materials. From this point of view, the present work is divided into two main parts. The first part is dealing with the preparation and characterization of alkaline polymer electrolyte membrane based on polyethylene oxide and polyvinylpyrrolidone. The alkaline polymer electrolyte membranes were prepared by two different techniques: immersing the irradiated prepared membranes in different concentration of KOH solutions, and addition of various amounts of KOH to (PEO/PVP) mixture solution during the preparation step. Exposing the prepared membranes to different gamma irradiation doses causes an improvement in the membranes properties such as water solubility and thermal properties. The structure and morphology of the prepared polymer membranes were studied by FTIR spectroscopy and scanning electron microscope. Furthermore, the ionic conductivity of alkaline (PEO/PVP) electrolyte membranes was calculated from Ac impedance spectra. The results obtained showed that the membranes prepared by immersion technique have better properties than the membranes prepared by addition technique. Concerning the second part, urea formaldehyde (UF) as a thermoset amino resin, was modified by exposing to different gamma irradiation doses and blending with various amounts of vinyl acetate versatic ester latex (VAcVe). Gamma irradiation induced the crosslinking of pure UF and (UF/VAcVe) blends. The change in the structure of pure UF and (UF/VAcVe) blends before and after irradiation was investigated by FTIR spectroscopy. Moreover, physical properties such as insoluble fraction percent, water absorption behavior, and effect of dilute acid and alkali were studied. Thermal and mechanical properties were investigated in terms of thermogravimetric analysis and compacting strength measurement. The results

Release mechanisms of acetaminophen from polyethylene oxide/polyethylene glycol matrix tablets utilizing magnetic resonance imaging.

Science.gov (United States)

Tajiri, Tomokazu; Morita, Shigeaki; Sakamoto, Ryosaku; Suzuki, Masazumi; Yamanashi, Shigeyuki; Ozaki, Yukihiro; Kitamura, Satoshi

2010-08-16

Release mechanism of acetaminophen (AAP) from extended-release tablets of hydrogel polymer matrices containing polyethylene oxide (PEO) and polyethylene glycol (PEG) were achieved using flow-through cell with magnetic resonance imaging (MRI). The hydrogel forming abilities are observed characteristically and the layer thickness which is corresponding to the diffusion length of AAP has a good correlation with the drug release profiles. In addition, polymeric erosion contribution to AAP releasing from hydrogel matrix tablets was directly quantified using size-exclusion chromatography (SEC). The matrix erosion profile indicates that the PEG erosion kinetic depends primarily on the composition ratio of PEG to PEO. The present study has confirmed that the combination of in situ MRI and SEC should be well suited to investigate the drug release mechanisms of hydrogel matrix such as PEO/PEG. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Cross-linked polyethylene does not reduce wear in total knee arthroplasty.

Science.gov (United States)

Lasurt-Bachs, S; Torner, P; Maculé, F; Prats, E; Menéndez-García, F; Ríos-Guillermo, J; Torrents, A

To compare two different types of inserts: Ultra-high molecular weight polyethylene (UHMWPE) and cross-linked polyethylene with a quantitative and qualitative study of polyethylene wear particles in synovial fluid 3 years after total knee arthroplasty. A prospective, randomized, controlled cohort study with blinded evaluation was carried out on 25 patients undergoing staged bilateral total knee replacement, 6 months apart. Knee arthrocentesis was performed on 12 patients 3 years after surgery, and the polyethylene particles were analyzed. No significant differences were found in the number of particles generated by the two different types of inserts at 3 years from total knee arthroplasty (3,000×: x¯ cross-linked=849.7; x¯ UHMWPE=796.9; P=.63; 20,000×: x¯ cross-linked=66.3; x¯ UHMWPE=73.1; P=.76). Likewise, no differences in the probability of finding elongated (χ 2 =0.19; P=.66) or rounded (χ 2 =1.44; P=.23) particles in both types of inserts were observed. However, the probability of finding fibrillar particles is 3.08 times greater in UHMWPE. Cross-linked polyethylene does not significantly reduce the generation of polyethylene particles in patients with total knee arthroplasty, 3 years after the surgical procedure. Copyright © 2018 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Atomistic simulation of CO 2 solubility in poly(ethylene oxide) oligomers

KAUST Repository

Hong, Bingbing; Panagiotopoulos, Athanassios Z.

2013-01-01

We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide

Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acrylonitrile-butadiene rubber

International Nuclear Information System (INIS)

Reinholds, Ingars; Kalkis, Valdis; Merijs-Meri, Remo; Zicans, Janis; Grigalovica, Agnese

2016-01-01

In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100–300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the kinetics of thermorelaxation and the residual shrinkage stresses of previously oriented (stretched up to 100% at above melting temperature of HDPE and followed by cooling to room temperature) specimens of irradiated HDPE/NBR blends under isometric heating–cooling mode. The compatibility between the both components was enhanced due to the formation of cross-linked sites at amorphous interphase. The results showed increase of mechanical stiffness of composites with increase of irradiation dose. The values of gel fraction compared to thermorelaxation stresses increased with the growth of irradiation dose level, as a result of formation cross-linked sites in amorphous PP/NBR interphase. - Highlights: • Binary blends of HDPE/NBR have been irradiated with 5 MeV accelerated electrons. • Increase of NBR content and irradiation dose improves cross-linking efficiency. • Thermo-shrinkage and residual stresses are investigated for oriented specimens. • Cross-linked HDPE/NBR composites can be successfully used as thermos-shrinkable materials.

Wall shear stress fixed points in cardiovascular fluid mechanics.

Science.gov (United States)

Arzani, Amirhossein; Shadden, Shawn C

2018-05-17

Complex blood flow in large arteries creates rich wall shear stress (WSS) vectorial features. WSS acts as a link between blood flow dynamics and the biology of various cardiovascular diseases. WSS has been of great interest in a wide range of studies and has been the most popular measure to correlate blood flow to cardiovascular disease. Recent studies have emphasized different vectorial features of WSS. However, fixed points in the WSS vector field have not received much attention. A WSS fixed point is a point on the vessel wall where the WSS vector vanishes. In this article, WSS fixed points are classified and the aspects by which they could influence cardiovascular disease are reviewed. First, the connection between WSS fixed points and the flow topology away from the vessel wall is discussed. Second, the potential role of time-averaged WSS fixed points in biochemical mass transport is demonstrated using the recent concept of Lagrangian WSS structures. Finally, simple measures are proposed to quantify the exposure of the endothelial cells to WSS fixed points. Examples from various arterial flow applications are demonstrated. Copyright © 2018 Elsevier Ltd. All rights reserved.

A directional entrapment modification on the polyethylene surface by the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether

Science.gov (United States)

Lu, Qiang; Chen, Yi; Huang, Juexin; Huang, Jian; Wang, Xiaolin; Yao, Jiaying

2018-05-01

A novel entrapment modification method involving directional implantation of the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether (AEO) into the high-density polyethylene (HDPE) surface is proposed. This modification technique allows the AEO modifier to be able to spontaneously attain and subsequently penetrate into the swollen HDPE surface with its hydrophobic stearyl segment, while its hydrophilic poly(ethylene oxide) (PEO) segment spontaneously points to water. The AEO modifier with a HLB number below 8.7 was proved appropriate for the directional entrapment, Nevertheless, AEOs with larger HLB numbers were also effective modifiers in the presence of salt additives. In addition, a larger and hydrophobic micelle, induced respectively by the AEO concentration above 1.3 × 10-2 mol/L and the entrapping temperature above the cloud point of AEO, could lead to a sharp contact angle decline of the modified surface. Finally, a hydrophilic HDPE surface with the modifier coverage of 38.9% was reached by the directional entrapment method, which is far larger than that of 19.2% by the traditional entrapment method.

Ion acceleration and D-D nuclear fusion in laser-generated plasma from advanced deuterated polyethylene.

Science.gov (United States)

Torrisi, Lorenzo

2014-10-23

Deuterated polyethylene targets have been irradiated by means of a 1016 W/cm2 laser using 600 J pulse energy, 1315 nm wavelength, 300 ps pulse duration and 70 micron spot diameter. The plasma parameters were measured using on-line diagnostics based on ion collectors, SiC detectors and plastic scintillators, all employed in time-of-flight configuration. In addition, a Thomson parabola spectrometer, an X-ray streak camera, and calibrated neutron dosimeter bubble detectors were employed. Characteristic protons and neutrons at maximum energies of 3.0 MeV and 2.45 MeV, respectively, were detected, confirming that energy spectra of reaction products coming from deuterium-deuterium nuclear fusion occur. In thick advanced targets a fusion rate of the order of 2 × 108 fusions per laser shot was calculated.

On the mechanism of charge transport in low density polyethylene

Science.gov (United States)

Upadhyay, Avnish K.; Reddy, C. C.

2017-08-01

Polyethylene based polymeric insulators, are being increasingly used in the power industry for their inherent advantages over conventional insulation materials. Specifically, modern power cables are almost made with these materials, replacing the mass-impregnated oil-paper cable technology. However, for ultra-high dc voltage applications, the use of these polymeric cables is hindered by ununderstood charge transport and accumulation. The conventional conduction mechanisms (Pool-Frenkel, Schottky, etc.) fail to track high-field charge transport in low density polyethylene, which is semi-crystalline in nature. Until now, attention was devoted mainly to the amorphous region of the material. In this paper, authors propose a novel mechanism for conduction in low density polyethylene, which could successfully track experimental results. As an implication, a novel, substantial relationship is established for electrical conductivity that could be effectively used for understanding conduction and breakdown in polyethylene, which is vital for successful development of ultra-high voltage dc cables.

Microbiological and sensory evaluation of the shelf-life of irradiated chicken breast meat

International Nuclear Information System (INIS)

Miyagusku, L.; Chen, F.; Leitao, M.F. de F.; Baffa, O.

2003-01-01

Kraft paper boxes containing 10 expanded polystyrene trays with 200g skinless deboned chicken breast each were irradiated with 60 Co source of a Nordion JS7500 irradiator. The trays were previously wrapped with polyethylene film. The samples were exposed to 1.5; 3.0 and 7.0 kGy doses in the static mode at 0º and 180º in relation to the irradiation beam. Set of 18 alanine+paraffin dosimeters per treatment were distributed inside the boxes for evaluation of irradiation dose homogeneity. A separeted dose calibration curve was obtained by irradiating in the range of 1 to 10kGy. After the irradiation, the chicken breasts were stored at 5±1ºC for 39 days and were analysed microbiologically in total psychrotrophic aerobic bacteria, total mesophilic aerobic bacteria, molds and yeasts, Pseudomonas spp, Enterobacteriaceae, lactic bacteria counts and E.coli during the storage period. The results revealed a linear behaviour of the alanine+paraffin dosimeters in the range of 1 to 10kGy irradiation. In regard to the microbiological aspect, compared to the shelf-life of 5 days for the controls, there were a increasing of 1.75; 4.40 e 7.0 times shelf-life for chicken breasts irradiated with 1.5; 3.0 and 7.0kGy, respectively. There was an increasing change of the smell of burnt as the irradiation doses increased. Thus, 3kGy dose was considered as the ideal dose to assure a longer shelf-life to the product, without perceptible changes in the aspect [pt

Thiolated polyethylene oxide as a non-fouling element for nano-patterned bio-devices

International Nuclear Information System (INIS)

Lisboa, Patricia; Valsesia, Andrea; Colpo, Pascal; Gilliland, Douglas; Ceccone, Giacomo; Papadopoulou-Bouraoui, Andri; Rauscher, Hubert; Reniero, Fabiano; Guillou, Claude; Rossi, Francois

2007-01-01

This work describes the synthesis of a thiolated polyethylene oxide that self-assembles on gold to create a non-fouling surface. Thiolated polyethylene oxide was synthesised by reacting 16-mercaptohexadecanoic acid with polyethylene glycol mono methyl ether. The coverage of the thiolated polyethylene oxide on gold was studied by cyclic voltammetry, and the modified surfaces were characterised by X-ray photoelectron spectroscopy and ellipsometry. Protein resistance was assessed using quartz crystal microbalance. Results showed a non-fouling character produced by the thiolated polyethylene oxide. The synthesised product was used as the passivation layer on nano-patterned surfaces consisting of arrayed nano-spots, fabricated by plasma based colloidal lithography. The specific adsorption of anti-bovine serum albumin in the mercaptohexadecanoic acid spots was verified by atomic force microscopy

Fast neutron dosimetry using CR-39 track detectors with polyethylene as radiator

International Nuclear Information System (INIS)

Castillo, F.; Espinosa, G.; Golzarri, J.I.; Osorio, D.; Rangel, J.; Reyes, P.G.; Herrera, J.J.E.

2013-01-01

The chemical etching parameters (etching time, temperature, normality of etchant, etc.) for the use of CR-39 (allyl diglycol carbonate – Lantrack ® ) as a fast neutron dosimeter have been optimized. The CR-39 chips, placed under a 1.5 mm polyethylene radiator, were exposed for calibration to an 241 Am-Be source at different time intervals for a given neutron fluence. After several chemical etching processes of the detectors with different conditions, the optimum characteristics for the chemical etching were found at 6N KOH solution, 60 ± 1 °C, for 12 h. An accurate relationship between the dose and fluence calculations was obtained as a function of the track density. - Highlights: ► Optimum etching time for fast neutron irradiated CR-39 track detectors is found. ► Relationship between dose and fluence obtained as a function of the track density. ► Results are consistent with those reported elsewhere, and extend the dose range

Understanding the fluid mechanics behind transverse wall shear stress.

Science.gov (United States)

Mohamied, Yumnah; Sherwin, Spencer J; Weinberg, Peter D

2017-01-04

The patchy distribution of atherosclerosis within arteries is widely attributed to local variation in haemodynamic wall shear stress (WSS). A recently-introduced metric, the transverse wall shear stress (transWSS), which is the average over the cardiac cycle of WSS components perpendicular to the temporal mean WSS vector, correlates particularly well with the pattern of lesions around aortic branch ostia. Here we use numerical methods to investigate the nature of the arterial flows captured by transWSS and the sensitivity of transWSS to inflow waveform and aortic geometry. TransWSS developed chiefly in the acceleration, peak systolic and deceleration phases of the cardiac cycle; the reverse flow phase was too short, and WSS in diastole was too low, for these periods to have a significant influence. Most of the spatial variation in transWSS arose from variation in the angle by which instantaneous WSS vectors deviated from the mean WSS vector rather than from variation in the magnitude of the vectors. The pattern of transWSS was insensitive to inflow waveform; only unphysiologically high Womersley numbers produced substantial changes. However, transWSS was sensitive to changes in geometry. The curvature of the arch and proximal descending aorta were responsible for the principal features, the non-planar nature of the aorta produced asymmetries in the location and position of streaks of high transWSS, and taper determined the persistence of the streaks down the aorta. These results reflect the importance of the fluctuating strength of Dean vortices in generating transWSS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extending the shelf-life of cocoyam leaves(xanthosoma sagitifolium) through blanching, irradiation and low temperature storage

International Nuclear Information System (INIS)

Afrifa, J.T.

2013-07-01

Cocoyam leaf (Xanthosoma sagiitifolium) (,Kontommire') is arguably one of the most readily available and cheap indigenous leafy vegetable that is commonly consumed in Ghana. It is noted to be a good source of minerals, vitamins and soluble fibre when consumed in its fresh (not raw though) state. However, this vegetable is highly perishable. Dehydration methods and jute sack storage are usually used for its preservation. However, these lead to discolouration, loss of some nutrients, and exposure to microbial contamination thus reducing the general acceptability by consumers. In view of this, a study was conducted to process and preserve the leaves in their fresh state. Preservation methods investigated were: refrigeration, steam blanching, gamma irradiation and a combination of these methods. The effect of the various preservation methods on some physicochemical properties (moisture content and dry matter by gravimetric method, vitamin C (ascorbic acid) was determined by iodometric titration method, crude protein was determined by Kjeldahl method, colour change using a Minolta CR310 colorimeter, pH using the Mettler Toledo pH meter (model:T3KfTLH); phytochemical properties (total phenolic using the Folin ciocalteau method and total flavonoids using aluminium chloride colorimetric method); microbial quality (total viable count, total coliforms, yeast and moulds count using serial dilution); consumer acceptance using a 9-point hedonic scale to assess the colour, texture and odour. The best packaging material for effective storage was also investigated. Fresh, fully opened leaves of cocoyam which were two (2) weeks old were collected from the Biotechnology and Nuclear Agriculture Research Institute (BNARI) farm and used for the study. They were decontaminated by washing in fifty (50) % of brine solution and shredded and apportioned for the various treatments, packaged into zip-lock polyethylene bags and hermetically sealed bags. The shelf-life study lasted for

Highly Enriched Uranium Metal Annuli and Cylinders with Polyethylene Reflectors and/or Internal Polyethylene Moderator

International Nuclear Information System (INIS)

Tyler Sumner; J. Blair Briggs; Leland Montierth

2007-01-01

A variety of critical experiments were constructed of enriched uranium metal during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, experiments of uranium metal annuli with and without polyethylene reflectors and with the central void region either empty or filled with polyethylene were evaluated under ICSBEP Identifier HEU-MET-FAST-076. The outer diameter of the uranium annuli varied from 9 to 15 inches in two-inch increments. In addition, there were uranium metal cylinders with diameters varying from 7 to 15 inches with complete reflection and reflection on one flat surface to simulate floor reflection. Most of the experiments were performed between February 1964 and April 1964. Five partially reflected (reflected on the top only) experiments were assembled in November 1967, but are judged by the evaluators not to be of benchmark quality. Twenty-four of the twenty-five experiments have been determined to have fast spectra. The only exception has a mixed spectrum. Analyses were performed in which uncertainty associated with five different parameters associated with the uranium parts and three associated with the polyethylene parts was evaluated. Included were uranium mass, height, diameter, isotopic content, and impurity content and polyethylene mass, diameter, and impurity content. There were additional uncertainties associated with assembly alignment, support structure, and the value

The effects of gamma irradiation on the fate of hindered phenol antioxidants in food contact polymers. Analytical and 14C-labelling studies

International Nuclear Information System (INIS)

Allen, D.W.; Leathard, D.A.; Smith, C.

1991-01-01

The extractable levels of two hindered phenol antioxidants (Irganox 1076 and Irganox 1010) present in PVC, polyethylene and polypropylene have been monitored by HPLC techniques following progressive exposure of the polymers to 60 Co(gamma) radiation. There is a gradual diminution in the extractable levels of each antioxidant as irradiation progresses as a result of transformation of the antioxidants in the oxidation reactions ensuing during irradiation. Experiments involving the use of a 14 C-labelled sample of Irganox 1076 in polyolefins have provided evidence of covalent binding of antioxidant degradation products to the polymer following gamma irradiation. However, there is also evidence of the formation of extractable degradation products, the identity of which is as yet unknown. (author)

The effects of gamma irradiation on the fate of hindered phenol antioxidants in food contact polymers. Analytical and 14C-labelling studies

Science.gov (United States)

Allen, David W.; Leathard, David A.; Smith, Christine

The extractable levels of two hindered phenol antioxidants (Irganox 1076 and Irganox 1010) present in PVC, polyethylene and polypropylene, have been monitored by HPLC techniques following progressive exposure of the polymers to 60Co γ radiation. There is a gradual diminution in the extractable levels of each antioxidant as irradiation progresses as a result of transformation of the antioxidants in the oxidation reactions ensuing during irradiation. Experiments involving the use of a 14C-labelled sample of Irganox 1076 in polyolefins have provided evidence of covalent binding of antioxidant degradation products to the polymer following gamma irradiation. However, there is also evidence of the formation of extractable degradation products, the identity of which is as yet unknown.

Thermal characterization of the HDPE/LDPE blend (10/90) irradiated using γ-rays

International Nuclear Information System (INIS)

Puig, C.C.; Albano, C.; Laredo, E.; Quero, E.; Karam, A.

2010-01-01

Gamma irradiation effect over the properties of slow cooled and fast cooled HDPE/LDPE 10/90 blend was studied. The blend and the neat polyethylenes were irradiated at room temperature in the presence of air using the following doses (4.8 kGy/h): 0, 50, 150, 400 and 1000 kGy. Differential scanning calorimetry (DSC) experiments were carried out using the following heating rates: 5, 10 and 20 deg. C/min. DSC results for the slow and fast cooled blend showed traces with three melting peaks and with increasing irradiation dose two melting peaks were obtained, i.e. the high melting peak shifts toward lower temperatures to merge with the intermediate melting peak into one endotherm. No changes in crystal structure by X-ray diffraction were found as a result of samples irradiation. Radiation crosslinking prevents crystal rearrangements during heating in the DSC. Gel content and melt flow index (MFI) measurements showed that radiation induced a high degree of crosslinking for all samples; gel content values were above 50% and a drop of more than 90% in the MFI was found. Irradiation of slow cooled samples resulted in larger values of gel content and lower MFI values than for fast cooled samples, mainly because of the higher degree of crosslinking for the former.

Thermal characterization of the HDPE/LDPE blend (10/90) irradiated using gamma-rays

Energy Technology Data Exchange (ETDEWEB)

Puig, C.C., E-mail: cpuig@usb.v [Universidad Simon Bolivar, Departamento de Ciencia de los Materiales, Grupo de Polimeros USB, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Albano, C., E-mail: calbano@ivic.v [Instituto Venezolano de Investigaciones Cientificas (IVIC), Centro de Quimica, Laboratorio de Polimeros, Apdo. 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of); Universidad Central de Venezuela, Facultad de Ingenieria, Escuela de Ingenieria Quimica, Laboratorio de Polimeros, Caracas (Venezuela, Bolivarian Republic of); Laredo, E. [Universidad Simon Bolivar, Departamento de Fisica, Grupo de Fisica de Materiales Amorfos y Cristalinos, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Quero, E. [Universidad Simon Bolivar, Departamento de Ciencia de los Materiales, Grupo de Polimeros USB, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Karam, A. [Instituto Venezolano de Investigaciones Cientificas (IVIC), Centro de Quimica, Laboratorio de Polimeros, Apdo. 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of)

2010-05-01

Gamma irradiation effect over the properties of slow cooled and fast cooled HDPE/LDPE 10/90 blend was studied. The blend and the neat polyethylenes were irradiated at room temperature in the presence of air using the following doses (4.8 kGy/h): 0, 50, 150, 400 and 1000 kGy. Differential scanning calorimetry (DSC) experiments were carried out using the following heating rates: 5, 10 and 20 deg. C/min. DSC results for the slow and fast cooled blend showed traces with three melting peaks and with increasing irradiation dose two melting peaks were obtained, i.e. the high melting peak shifts toward lower temperatures to merge with the intermediate melting peak into one endotherm. No changes in crystal structure by X-ray diffraction were found as a result of samples irradiation. Radiation crosslinking prevents crystal rearrangements during heating in the DSC. Gel content and melt flow index (MFI) measurements showed that radiation induced a high degree of crosslinking for all samples; gel content values were above 50% and a drop of more than 90% in the MFI was found. Irradiation of slow cooled samples resulted in larger values of gel content and lower MFI values than for fast cooled samples, mainly because of the higher degree of crosslinking for the former.

Degradation of electrical insulation of polyethylene under thermal and radiation environment, (4). [Gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Shuhei; Murabayashi, Fumio; Sawa, Goro [Mie Univ., Tsu (Japan); Yamaguchi, Shinji; Ieda, Masayuki

1982-12-01

Although the quality assurance guideline for the cables used for the safety and protection systems of nuclear power plants is given by IEEE Standards 323 and 383-1974, in addition, it is important to clarify the aging process under the complex environment of heat and radiation and the equivalence of the accelerated aging test of insulating materials. The authors performed the sequential (H.T-..gamma.. or ..gamma..-HT) and simultaneous (..gamma.., HT) application of respective aging factors of heat and radiation to non-additive low density polyethylene films by changing dose rate as the first stage, to clarify the dose rate dependence of the aging. They mainly investigated the dielectric properties, and forwarded investigation based on the change of carbonyl group by infrared spectrometry and residual free radicals by ESR analysis. In the samples irradiated with ..gamma..-ray only and those irradiated with ..gamma..-ray after thermal treatment for 7 hours at 90 deg C, the absorption coefficient ..cap alpha.. of carbonyl group increased with dose in the range from 3 Mrad to 60 Mrad, and both samples showed approximately the same ..cap alpha.. value. The ..cap alpha.. value of the samples thermally treated after irradiation was larger than that of the samples treated in the reverse order, and the difference between them increased with the increase of dose. The values of dielectric tangent delta at room temperature and 1 kHz for the samples (..gamma..) and (HT-..gamma..) increased with dose, and were almost the same, but those for the samples (..gamma..-HT) and (..gamma.., HT) were larger than the former two.

Efficacy of polyethylene glycol 4000 on constipation of

Directory of Open Access Journals (Sweden)

ZHANG Lian-yang

2010-06-01

Full Text Available Constipation is one of themost common chronic gastrointestinal problems. The estimated incidence of constipation in the United States is3% to 19% in general population.1,2 Patientswith head injuries, spinal cord injuries, pelvic fractures, lower extremity fractures ormultiple traumas require a long-term bed rest, during which the incidence of constipation reached as high as 50%.3,4 Constipation always brings inconvenience and tremendous suffering to patientsand strongly influences the recovery from primary disease. Irritants or lubricants can relieve the symptoms, but long-term application of them may lead to side effects like melanosis coli5 and cathartic colon6. The absorption of fat soluble vitamins is also affected.7 Polyethylene glycol 4000 (trade name: Forlax®, a long chain polymer with a high molecular weight, can conjugate withwater molecule through hydrogen bond to increase the water content and volume of stools, thereby, facilitate bowelmovement and defecation.8,9 It is neither absorbed nor metabolized in the digestive tract, hence it is highly safe and well tolerable. Thus, long-term medication of polyethylene glycol 4000 is conducive to the reconstruction of normal defecation pattern. Therefore, polyethylene glycol 4000 is now being widely used as the mainstay adult chronic functional constipation management.10,11 The aim of this study was to verify the efficacy and safety of polyethylene glycol 4000 on adult functional constipation of posttraumatic bedridden patients.

Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

NARCIS (Netherlands)

Hageman, J.C.L.; Meier, Robert J.; Heinemann, M.; Groot, R.A. de

1997-01-01

The Young modulus for crystalline polyethylene is calculated using ab initio molecular dynamics based on density functional theory in the local density approximation (DFT-LDA). This modulus, which can be seen as the ultimate value for the Young modulus of polyethylene fibers, is found to be 334 GPa.

Cementitious building material incorporating end-capped polyethylene glycol as a phase change material

Science.gov (United States)

Salyer, Ival O.; Griffen, Charles W.

1986-01-01

A cementitious composition comprising a cementitious material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the compositions are useful in making pre-formed building materials such as concrete blocks, brick, dry wall and the like or in making poured structures such as walls or floor pads; the glycols can be encapsulated to reduce their tendency to retard set.

Comparative Results From a National Joint Registry Hip Data Set of a New Cross-Linked Annealed Polyethylene vs Both Conventional Polyethylene and Ceramic Bearings.

Science.gov (United States)

Epinette, Jean-Alain; Jolles-Haeberli, Brigitte M

2016-07-01

Major concerns in hip arthroplasty concern the fate of bearing surfaces. Highly cross-linked polyethylene materials (HXLPE) currently demonstrate successful in vitro results with new technical procedures of cross-linking the polyethylene material, whereas processing the polyethylene below its melting temperature to produce so-called "annealed HXLPE" would allow retention of important mechanical properties. Data released by the National Joint Registry of England and Wales addressing in 45,877 hips the same Trident uncemented cup, allowed us to compare the performance of a consecutive cohort of patients implanted with the newest generation of annealed HXLPE acetabular bearings (X3: 21,470) vs 2 consecutive nonselected cohorts, one with conventional polyethylene (N2vac: 8225) and one with ceramic-on-ceramic (CoC) hip bearings (AL: 16,182). The main end point in survivorship has been first defined as revision for any cause, then for any cause which could be related to a failure of the bearing couple. At 6-year follow-up, all Trident cups demonstrated encouraging global survival cumulative rates all between 95% and 99%. A first study demonstrated better survivorship with X3-HXLPE liners vs conventional ultrahigh molecular weight polyethylene. On the second parallel study, the cumulative survival rates were better for X3 liners as compared to CoC bearings. Moreover, when ranking the yearly cumulative percent revision rates, again the best results were obtained with X3 liners with small alumina heads (cumulative percent revision rate at 0.298). Within the frame of this Trident study, the use of this X3 highly cross-linked annealed polyethylene could be considered as a reliable alternate solution to CoC bearings. Copyright © 2016 Elsevier Inc. All rights reserved.

Manipulating interactions between functional colloidal particles and polyethylene surfaces using interfacial engineering.

Science.gov (United States)

Ziani, Khalid; Barish, Jeffrey A; McClements, David Julian; Goddard, Julie M

2011-08-01

The purpose of this study was to examine the interaction between lipid droplets and polyethylene surfaces, representative of those commonly used in food packaging. Lipid droplets with various surface charges were prepared by homogenizing corn oil and water in the presence of surfactants with different electrical characteristics: non-ionic (Tween 80, T80), cationic (lauric arginate, LAE), and/or anionic (sodium dodecyl sulfate, SDS). The ionic properties of polyethylene surfaces were modified by UV-treatment. Stable emulsions containing small droplets (demulsions. Scanning electronic microscopy (SEM), confocal fluorescence microscopy, and ATR-FTIR showed that the number of droplets attached to the polyethylene surfaces depended on the droplet charge and the polyethylene surface characteristics. The greatest degree of droplet adsorption was observed for the cationic droplets to the UV-ozone treated polyethylene surfaces, which was attributed to electrostatic attraction. These results are important for understanding the behavior of encapsulated lipophilic components in food containers. Copyright © 2011 Elsevier Inc. All rights reserved.