Effect Of Radiation Crosslinking Research Articles

Effect of Radiation Crosslinking on the Yield Strength of a Carbon Fiber Reinforced Tetrafluoroethylene–Ethylene Copolymer

Effect of Radiation Crosslinking on the Yield Strength of a Carbon Fiber Reinforced Tetrafluoroethylene–Ethylene Copolymer

Effect of Radiation Crosslinking and Surface Modification of Cellulose Fibers on Properties and Characterization of Biopolymer Composites.

Recently, polymers have become the fastest growing and most widely used material in a huge number of applications in almost all areas of industry. In addition to standard polymer composites with synthetic matrices, biopolymer composites based on PLA and PHB matrices filled with fibers of plant origin are now increasingly being used in selected advanced industrial applications. The article deals with the evaluation of the influence and effect of the type of surface modification of cellulose fibers using physical methods (low-temperature plasma and ozone application) and chemical methods (acetylation) on the final properties of biopolymer composites. In addition to the surface modification of natural fibers, an additional modification of biocomposite structural systems by radiation crosslinking using gamma radiation was also used. The components of the biopolymer composite were a matrix of PLA and PHBV and the filler was natural cellulose fibers in a constant percentage volume of 20%. Test specimens were made from compounds of prepared biopolymer structures, on which selected tests had been performed to evaluate the properties and mechanical characterization of biopolymer composites. Electron microscopy was used to evaluate the failure and characterization of fracture surfaces of biocomposites.

An increase of the mechanical strength and hardness of polymeric materials radiation-crosslinked by X-ray radiation from an gaseous electric discharge

The problem of investigation of mechanical and electrophysical properties of polymeric materials crosslinked by X-ray radiation from a gaseous electric discharge is considered. The effect of radiation crosslinking on the mechanical strength and hardness of polymers is presented by the example of samples of various thicknesses (from 0.08 mm to 10 mm) of LDPE and HDPE made using crosslinking technology by X-ray radiation from a barrier gaseous electric discharge proposed in [1]. Experimental data obtained on samples of low molecular weight LDPE-107-02K and high molecular weight HDPE-271-82K made in the form of dumbbell, cut in accordance with GOST IEC 60811-2-1 from PE plates, are considered. To study the electrophysical properties and the depth of semi-absorption of X-ray radiation from gaseous electric discharge, LDPE and HDPE samples in the form of disks of different thicknesses were used.The depth of penetration of X-ray radiation from a gaseous discharge into LDPE-107-02K and HDPE-271-82K was estimated.Comparative studies of changes in the electrophysical properties of mechanical strength and hardness of cable LDPE under the influence of X-ray radiation from gaseous discharge and under the influence of an electron beam are carried out.It is shown that the mechanical strength and hardness of LDPE and HDPE can be increased by at least 30% and 60% respectively via radiation crosslinking by X-ray from a gaseous discharge.

Influence of an Increased Fiber Filler Content on the Elongation Behavior of Filled Films in the Thermoforming Process

Thermoforming belongs to one of the most important processes in polymer processing, especially in the packaging industry. It enables the forming of thermoplastic components into shaped parts at high temperatures. Since the thermoforming of films takes place in the rubbery state, amorphous thermoplastics are mainly processed, which have a wide rubbery state. Radiation crosslinking can be used to widen the thermoforming window of semi-crystalline thermoplastics. A benefit of the crosslinking is the increased short-term temperature resistance. In general, there are only a few investigations concerning the thermoforming of filled thin films. Within this investigation, the influence of an increasing glass fiber content up to 15 vol.-% as well as the effect of radiation crosslinking on the elongation behavior and the wall thickness distribution was examined. It can be summarized that especially thermoforming with an increased filler content at high areal draw ratios represents a challenge. Whereas non-crosslinked glass fiber filled films are thermoformable only at low areal draw ratios, radiation crosslinked films can be also formed at higher areal draw ratios without difficulties. For high filler contents and high areal draw ratios, no forming is possible at high areal draw ratios, although the films have been crosslinked. The use of radiation crosslinking enables the process limit in thermoforming of thin filled films to be increased and thus the range of applications to be extended greatly.

Влияние радиационной сшивки в электрическом газовом разряде на механическую прочность полиэтиленовой кабельной изоляции

Влияние радиационной сшивки в электрическом газовом разряде на механическую прочность полиэтиленовой кабельной изоляции

Change of notch impact strength depending on radiation dose and test temperature

The main purpose of this paper has been determine the effect of radiation crosslinking on the notch impact strength of polyamides filled with fiberglass. These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 66 and 132 kGy were compared) and on the test temperature (23–150 °C).

The Effect of Ageing on the Micro-Creep Properties of Radiation Cross-Linked Materials

Radiation crosslinking of polymeric materials have placed and nowadays in the field of long-term use of loaded products. This article aims to identify the long-term effect of radiation crosslinking on micro-creep properties. The article compares the micro-creep properties of HDPE measured two years ago with the results of tests conducted under the same conditions and on the same samples now. The effect of time on the mechanical properties of the radiation crosslinked materials was demonstrated in short-term tests. These findings demonstrate the positive effect of time on the evaluated parameters.

Preparation and Properties of γ-Rays Irradiation-Induced Crosslinked Sulfonated Polyimide Proton Exchange Membranes

To improve the performance of sulfonated polyimide (SPI) membrane, especially to heighten water stability, γ-rays irradiation-induced crosslinking is used to modify the SPI membrane. The effects of radiation crosslinking on SPI membrane are investigated. Their physical properties, membrane morphology, proton conductivity, membrane stability and mechanical property are measured and reported. In this study, 24 hours radiation treatment endow the SPI membrane (SPI-24h) with the optimum performance, remarkably improved the water stability with only slight sacrifice in proton conductivity.

Surface and Adhesive Properties of Low-Density Polyethylene after Radiation Cross-Linking

Radiation cross-linking gives inexpensive commodity plastics and technical plastics the mechanical, thermal, and chemical properties of high-performance plastic. This upgrading of the plastics enables them to be used in conditions which they would not be able to with stand otherwise. The irradiation cross-linking of thermoplastic materials via electron beam or cobalt 60 (gammy rays) is performed separately, after processing. Generally, ionizing radiation includes accelerated electrons, gamma rays and X-rays. Radiation processing with an electron beam offers several distinct advantages when compared with other radiation sources, particularly γ-rays and x-rays. The process is very fast, clean and can be controlled with much precision. There is no permanent radioactivity since the machine can be switched off. In contrast to γ-rays and x-rays, the electron beam can steered relatively easily, thus allowing irradiation of a variety of physical shapes. The energy-rich beta rays trigger chemical reactions in the plastics which results in networking of molecules (comparable to the vulcanization of rubbers which has been in industrial use for so long). The energy from the rays is absorbed by the material and cleavage of chemical bonds takes place. This releases free radicals which in next phase from desired molecular bonds. This article describes the effect of radiation cross-linking on the surface and adhesive properties of low-density polyethylene.

Sustained-release of flutamide from radiation-crosslinked poly(4-acryloyl morpholine-acrylic acid) hydrogels

The present work reports the effect of radiation cross-linking on aqueous solution of 4-acryloyl morpholine (ACMO)/acrylic acid (AA) in the presence of flutamide (FLT), an anticancer drug. Use of a γ-irradiation process within 5 kGy provided an insoluble hydrogel. Ultraviolet-visible absorption, fluorescence spectroscopy, and Fourier transform infrared spectroscopy were employed to study the complex formation of FLT with ACMO and AA. The ability of the prepared ACMO/AA-based hydrogels to be used as drug carriers for anticancer-specific drug delivery system was estimated using FLT as a model drug. In vitro drug release studies in a pH 7 buffer solution show that 20%–30% of the FLT was continuously released from the FLT-incorporated ACMO/AA hydrogel within 1 day, followed by a gradual release upon 7 days under in vitro non-degradation hydrogel conditions. The recognition affinity of the ACMO/AA/FLT hydrogel is increased when synthesized in a high-concentration template solution. Open image in new window

Effects of a radiation crosslinking on a drawn microporous HDPE film with a nucleating agent

The effects of crystallinity and radiation crosslinking on the physical properties of a microporous high density polyethylene (HDPE) film with Millad3988 as a nucleating agent were investigated. The pores of the HDPE film were affected by the crystallinity. The crystallinity of the HDPE films increased with increasing Millad3988 amount up to 0.1 wt% but decreased with further addition. The mechanical characteristics of the HDPE containing Millad3988 films improved with increasing irradiation dose up to 50 kGy, but decreased at 75 kGy due to severe degradation. The thermal shrinkage behavior of the HDPE films decreased with increasing radiation dose up to 50 kGy. The porosity of the stretched HDPE/Millad3988 films after γ-ray radiation increased with increasing γ-ray radiation dose up to 50 kGy. The pores of the irradiated films were formed more easily by a stretching due to the formation of a crosslinked structure.

The radiation destruction of crystalline polymers—I. The effect of radiation crosslinking on crystallinities of polyesters

Changes in crystallinity of crystalline polyethylene glycol terephthalate (PET) and polyhexamethylene terephthalate (PHT) irradiated by γ-ray (0–30 MGy) were investigated by means of a differential scanning calorimeter (DSC). The results of the first-run indicated that the melting point of both polyesters decreases with the increase of dose, and the half widths of melting peaks decrease at first and then increase with dose, that is there is a minimum half-width at some dose. The results of the second-run DSC indicate that the properties of recrystalline material are related to the crystal states in which the samples were irradiated. The entropies of fusion, Δ S, were calculated from T m and Δ H. Δ S decreases with dose increase for each polyester, and PHT, in which more crosslinking occurs, gives greater Δ S than PET. The result is discussed from the point of view of crosslinking taking place within each crystal.

Ultrasonic and thermal properties of γ‐irradiated low‐density polyethylene

AbstractThe ultrasonic pulse‐echo technique and differential thermal analysis were utilized to characterize and to monitor the effect of γ‐irradiation on the sonic modulus and the heat effect of low‐density polyethylene. The sonic wave velocity, sonic modulus, and specific gravity exhibit a minimum for samples irradiated at 10 Mrad. A minimum in the heat capacity was observed at 1 Mrad. The estimated relative change of the activation energy of ordering exhibits a minimum at 100 Mrad. Below 10 Mrad, the perturbation and the loss of the crystalline phase override the effect of radiation cross‐linking. From 10 to 100 Mrad, the effect of cross‐linking as well as that of crystallinity are prevailing. Oxidative degradation is dominating above 100 Mrad. © 1993 John Wiley & Sons, Inc.

Effect of radiation cross-linking on the thermomechanical properties of fibres from a tetrafluoroethyleneethylene copolymer

The effect of radiation dose on the heat-resistance of fibres from a tetrafluoroethyleneethylene copolymer has been investigated.

The effect of radiation cross-linking on the mechanical properties of polyethylene sheets

The high density polyethylene (HDPE) sheets thickness 3mm were irradiated by 60Co γ-ray. Its gel fraction increases with increasing dosage. The melt index of irradiated samples decreases significantly with dosage from 1 kGy to 12kGy and the number average molecular weight of samples increases linearly. The mechanical properties including yield strength, breaking strength and breaking elongation percentage of irradiated HDPE sheets increase at low doses and then decrease at high doses. All of them have a peak value at 180 kGy. The Young's modulus of samples also increases linearly with increasing dosage. The aging tests of samples in irradiation doses of 180 and 360 kGy were carried out respectively and compared with non-irradiated samples.

Effect of crosslinking on the low-temperature relaxation behavior of polyethylene

Abstract The dynamic mechanical properties of polyethylene crosslinked by chemical methods and by electron irradiation were determined from 77°K to 250°K on an acoustic spectrometer at a frequency of approximately 50 Hz. Parallel stress-strain, swelling, and x-ray scattering experiments were also carried out to determine the degree of crosslinking and crystallinity. It is found that the effect of chemical crosslinking is to suppress the loss intensity of the γ relaxation in polyethylene while preserving the symmetrical shape of the loss curve without changing the temperature position. The effect of radiation crosslinking, however, also changes the symmetrical nature of the curves. Possible mechanisms of these observed changes are discussed.