Irradiated Polyethylene Terephthalate Research Articles

Effect of gamma ray irradiation and packaging on the storage quality of kodo millet (Paspalum scrobiculatum L.) flour

Kodo millet is one of the small millet species, grown widely in the tropical/subtropical regions. In order to prevent the problem of post-harvest losses, various preservation techniques have been used such as irradiation and suitable packaging material. In the present study, shelf life of kodo millet flour was investigated using gamma rays at 1.5 kilogray (kGy) (irradiation, IR) and different packaging materials including low-density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET) and metallized polypropylene (MPP) for a period of three months. Every fortnight the samples from these treatments were drawn for biochemical changes (moisture, peroxide value, alcoholic acidity and FFA), insect infestation and microbial growth. By the end of storage period, significant (P < 0.01) increase of moisture, peroxide value, alcoholic acidity and FFA content was noticed in the control samples followed by non-irradiated PP (10.50 %, 3.8 mEq/Kg and 1.25%) and LDPE (9.48 %, 3.4 mEq and 1.20 %) packed flour as compared to irradiated MPP and PET packed samples. Insect infestation started after 15 days of storage in steel boxes which increased in countless numbers by the end of storage period. Similarly, insect population was noticed after 30 and 60 days in non irradiated and irradiated PP and LDPE covers respectively. While, there was no insect infestation in case of irradiated MPP and PET packed flour. Significant increase of bacterial load was observed in the control followed by non irradiated PP (4.2 cfu/g) and LDPE (3.8 cfu/g) covers. Sensory tests indicated that the irradiation has no adverse effect on the taste, appearance, flavor and overall acceptability (OAA) of the flat bread made from flour samples stored in these packaging materials. Thus, the kodo millet flour stored in MPP and PET pouches with irradiation dose of 1.5 kGy found to be suitable for safe storage up to three months under room temperature.

Fatigue Prediction Model and Stiffness Modulus for Semi-Flexible Pavement Surfacing Using Irradiated Waste Polyethylene Terephthalate-Based Cement Grouts

Semi-flexible pavement surfacing, or grouted macadam, is an alternative to conventional flexible and rigid pavement. It is constructed by injecting cementitious grout into the voids of an open-graded asphalt surfacing. The cement used in cementitious grouts has adverse environmental effects because of the carbon dioxide emission in cement production. The objective of this study was to investigate the potential of using irradiated waste polyethylene terephthalate (PET) and fly ash (FA) as a (partial) cement replacement in cementitious grouts for semi-flexible pavement surfacing. This study sought to assess the stiffness modulus and fatigue properties of the semi-flexible specimens prepared with control grout, regular PET (2.57% PET + 10% FA) and irradiated PET (4.75% PET + 10% FA)-based grouts and compares the stiffness modulus and fatigue properties of semi-flexible specimens with the conventional hot mix asphalt (HMA) concrete. The semi-flexible surfacing specimens showed superior performance, higher stiffness modulus, and better fatigue life than the hot mix asphalt. The difference in fatigue cycles was apparent at lower stress ratios of 25 and 30%. The semi-flexible pavement mixtures exceeded 100,000 cycles at the lowest stress ratio of 25%, while the HMA fatigue cycles were less than 100,000 cycles. Furthermore, the semi-flexible specimen with irradiated PET (which contain a higher amount of waste PET than the regular PET) showed similar stiffness modulus and fatigue life as the specimens with regular PET and control grout. The irradiation technique offers a sustainable solution for recycling higher amounts of waste PET in highway materials for semi-flexible pavement surfacing.

Estimation of the nano-pores diameter by conductometric measurements

s. Ionic transport properties and diameter of asymmetric conical nano-pores in polyethylene terephthalate membranes were calculated. These nano-pores were synthesized by chemical etching method in irradiated polyethylene terephthalate (PET) films. After etching, the transport characteristics weredocumented under stepping voltage with 2M ionic concentrations of Potassium halides i.e. KCl, KBr and KI. The symmetric bathing condition (same temperature and same pH value solution in both side of chamber) in electrochemical cell were accomplished. It is investigated that diameter of nano-pores is also evaluate by measuring the current rectification properties of track etched nano-pores.

Effective use of recycled waste PET in cementitious grouts for developing sustainable semi-flexible pavement surfacing using artificial neural network (ANN)

The effective way of recycling waste polyethylene terephthalate (PET) by exposing it to gamma rays, is adopted in formulating the compositions of cementitious grouts for semi-flexible pavement surfaces. The ordinary Portland cement in grouts was partially replaced by regular PET (2.5%–10%) and irradiated PET (2.5%–10%) combined with fly ash (FA) and silica fume (SF). The physical, mechanical, and microstructural characteristics of grouts were investigated, and the results achieved from regular and irradiated PET substituted cement gouts were used to develop single hidden layers (SHLs) and two hidden layers (THLs) neural network models. The test results show that replacing cement with regular PET or irradiated PET caused a significant increase in the flow value of cement grouts. When using regular PET, compressive strength is significantly reduced at all curing ages (53–78% at 1 d, 24%–46% at 7 d, and 23%–36% at 28 d). Some of the strength was restored when irradiated PET was used (the recovery is 20–30% at 1 d, 17–24% at 7 d, and 7–12% at 28 d). The pozzolanic characteristics of FA and SF led to an increase in compressive strength. The microstructural analysis by FESEM-EDX and XRD confirms that the irradiated PET causes densification and refinement of microstructure. The statistical evaluation using R, MAE, RMSE, and RSE reflects a close agreement of actual values to the predicted results for the developed ANN models. The proximal values of objective functions to zero represents no overfitting of the trained models. The value of R for all the developed models is ≥ 0.91, which depicts a strong correlation between experimental and predicted results of flow and compressive strength. It is possible to conclude that with the irradiation process, more waste PET can be recycled than regular PET while still achieving similar strength properties, thus providing a sustainable solution to the recycling of waste PET.

Induced gyrotropy in thin PET films before and after swift heavy ion irradiation evidenced from analysis of optical interference fringes

We present here experimental studies of the UV/vis/near IR transmission spectra of polyethylene terephthalate (PET) films before and after irradiation with Kr+15 ions of energy 1.75 MeV/a.u. and fluence of 1.9 × 10 10 cm−2. Our data show small variations (∼0.5%) in transmission between individual pristine PET film samples in the IR region of the spectrum, as would be expected for films produced to certain manufacturing tolerances. Swift heavy ion (SHI) irradiation of a sample reduces transmission in this region, but by less than the observed variation in transmission between individual pristine samples, and does not affect local transmission variations in the spectrum, indicating that SHI irradiation has not destroyed the molecular structure of the PET film responsible for these variations. We use established methods to separate our experimental spectra into interference-free transmission spectra and isolated interference fringes and estimate the absorption coefficient and dispersion of the refractive index for pristine and irradiated PET films. We show that the observed amplitude modulation of the interference fringes is due to the optical activity of our PET samples and is a signature of induced gyrotropy. In some spectral regions, we observe a refractive index that is negative relative to the Cauchy approximation. We provide evidence that this is due to the ordering/texture of chiral molecules in PET films, suggesting that very highly textured PET films may exhibit a greater degree of negativity.

Evolution of the absorption edge of PET films irradiated with Kr ions after thermal annealing and ageing

This paper presents the results of a study of the ageing and annealing of films of polyethylene terephthalate (PET) after irradiation with Kr ions. For the studies of ageing, PET film samples were irradiated normally to the surface with Kr 15+ ions of energy of 1.75 MeV/a.u. and various fluences between (1–10)x10 10 cm −2 and then kept for 7.5 months (5400 h) at room temperature in the dark in sealed cases with air removal. The studies of annealing were made on a PET sample irradiated with Kr 13+ ions of energy 1.2 MeV/a.u. at an angle of 40° to the normal and a fluence of 5 × 10 10 cm −2 . Annealing was carried out in the dark in sealed cases with air removal for 160 and 500 h at a temperature lower than the glass transition. UV/vis/near IR differential spectra were obtained for each sample in the wavelength range 308–1050 nm (photon energy 4.03–1.18 eV). We used an established technique to obtain interference-free transmission curves T(λ) for both pristine and irradiated PET film samples and a differential spectroscopy technique to obtain differential transmission spectra ΔT(λ) of the changes in transmission after ageing and annealing. For all samples, a region of increased transmission at short (UV) wavelengths and a region of reduced transmission at longer (red/near IR) wavelengths were observed. These changes result from, respectively, the decay of the smallest irradiation-induced chromophores that are responsible for the absorption of short-wave radiation and the growth in the numbers and size of chromophores with larger conjugation values. They confirm our previous experiments showing that swift heavy ion irradiation of PET films creates reversible non-covalent π–π c onjugation bonds between neighbouring chain molecules in polymer films. These results also confirm our hypothesis that under annealing and ageing the smallest, least stable irradiation-induced conjugations decay while larger, more stable, conjugations grow. Our results also indicate that oblique irradiation, for which the electric field vector has a significant component perpendicular to the film texture, can enhance the polarization effects of the interaction of neighbouring polymer chain molecules leading to electro-optical amplitude enhancement. • Evolution of the absorption edge of PET films irradiated with Kr ions. • PET sample irradiated with 84 Kr 13+ ions of energy 1.2 MeV/a.u. and fluence of 5 × 10 10 cm −2 at an angle of 40° to the normal. • Electro-optical studies of the effect of an electric field on the optical properties. • Analyze the UV–Vis spectro-interferograms.

Investigating the mechanical properties and fuel spillage resistance of semi-flexible pavement surfacing containing irradiated waste PET based grouts

Semi-flexible pavement surfacings are constructed from impregnating highly flowable cementitious grouts into the voids of open-graded asphalt wearing course layers. Semi-flexible surfacings offer superior load bearing and rutting resistance performance when compared to either conventional or polymer modified hot mix asphalts. On the other hand, when semi-flexible surfacings are used as part of a flexible pavement construction, they offer an economic alternative to concrete construction. In this laboratory investigation, the properties and performance of semi-flexible mixes containing three types of cementitious grouts (a control grout, a grout containing regular waste polyethylene terephthalate (PET) and a grout containing gamma-irradiated waste PET) were investigated and compared to the performance of a conventional hot mix asphalt (HMA). Test results showed that the properties of semi-flexible control specimens comprising 100% cementitious grout can be matched by specimens containing 2.75% regular PET as partial replacement to the cement. When gamma-irradiated PET is used, the cement replacement content can be increased to 4.75% whilst maintaining properties comparable to the control grout. It was thus argued that gamma-irradiation is a useful tool for enhancing product sustainability. The laboratory produced semi-flexible specimens were evaluated for the degree of grout impregnation, Marshall stability, indirect tensile strength, thermal expansion, moisture resistivity, and fuel resistivity. The results were compared directly to those obtained from testing conventional HMA specimens. All three semi-flexible mixtures exhibited superior performance compared to the HMA mixture in terms of Marshall stability, indirect tensile strength, resistance to moisture damage and resistance to fuel spillage.

Effect of Cement Grouts Containing Irradiated Polyethylene Terephthalate on Properties of Semi-Flexible Mixtures

The seme-flexible pavement surface is a hybrid type of pavement surface that combines the effect of both asphalt mix skeleton and cement grout. The current study investigates the influence of cement grouts containing irradiated waste polyethylene terephthalate (PET) on the performance of semi-flexible mixtures. The ordinary Portland cement was partially replaced by regular and irradiated PET as well as with fly ash (FA) in cement grouts. The air voids analysis, degree of grout saturation, Marshal stability, indirect tensile strength (ITS), and tensile strength ratio (TSR) of semi-flexible specimens were evaluated. The semi-flexible mixtures showed superior performance in terms of strength properties. The results indicate that with the irradiation process more waste PET (almost double) can be recycled as compared to regular waste PET in cement grouts for semi-flexible pavement surfaces. This approach will lead to a sustainable solution for recycling waste PET in highway materials for the construction of a hybrid type of pavement surface.

Ion track etching revisited. V. Etching of aged pristine and swift heavy ion-irradiated polyimide foils after treatment in hot ambient

In the previous papers of this series, the result of etching of fresh swift heavy ion (SHI)-irradiated polyethylene terephthalate (PET) foils after thermal annealing in various environments was studied to determine the extent to which thermal annealing is able not only to simulate aging of pristine polymer foils, but also SHI-irradiated foils. The etching results of these foils (obtained using breakthrough times of the etchant across the PET foils that were pre-annealed at different temperatures for constant times) did not always follow the predicted Arrhenius behavior, but showed dip-like deviations that were tentatively attributed to both SHI radiation and ambient effects to the glass transition temperature. To determine whether deviations from the simple Arrhenius behavior also occur for other irradiated polymers, we examined the effect of thermal annealing at different temperatures T of aged SHI-irradiated Kapton foils via the etchant breakthrough times across the SHI tracks. Interestingly, there appeared unexpected wide dip-like deviations from straight Arrhenius plots. Comparison of this curve with corresponding ones of aged non-irradiated Kapton foils, by determining the etchant breakthrough times across the foils, enabled us to assign the obtained high-temperature Arrhenius branch (for T > 80°C) to heal both aged and irradiated polymer foils from aging and/or radiation defects. In contrast, the pristine and irradiated aged samples annealed at lower temperatures follow completely different trends. As in the previous article on PET, we tend to assign the dip-like deviation of the SHI-irradiated Kapton again to the glass transition temperature of this highly radiation-damaged material.

Assessment of the Irradiation Exposure of PET Film with Swift Heavy Ions Using the Interference-Free Transmission UV-Vis Transmission Spectra.

This paper presents the results of a study of polyethylene terephthalate (PET) films irradiated with Ar and Kr ions at both normal orientation and an angle of 40° to the normal. Normal irradiation was performed using Ar8+ and Kr15+ ions with an energy of 1.75 MeV/au and fluences in the range (2–500) × 1010 cm−2 for Ar8+ ions and (1.6 − 6.5) × 1010 cm−2 for Kr15+ ions. Kr ions with an energy of 1.2 MeV/au and charges of 13+, 14+, and 15+ were used for angled irradiation. For each Kr ion charge value, three fluence values were used: 5 × 1010, 1 × 1011, and 2.5 × 1011 cm−2. It is well known that irradiation of PET films by swift heavy ions results in a red shift of the UV-vis transmission spectra absorption edge. The experimental transmission spectra exhibit well-defined interference fringes, which obscure the underlying transmission response. Using an existing technique to obtain interference-free transmission curves Tα(λ) for both pristine and irradiated PET film samples, we found that S, the total radiation-induced absorption of light by the PET film, is proportional to the logarithm of the fluence F. In addition to this dependence on the irradiating fluence, we also found that the charge of the irradiating ion has a significant influence on the position of the absorption edge in the UV-vis spectra. This provides experimentally independent evidence to confirm our previous results showing that ion charge has an effect on the post-irradiation state of PET films. We present a physical interpretation of the observed absorption edge red shift in irradiated PET films as being due to the growth of extended conjugated systems via the formation of intermolecular helical structures. Our investigations into the stability of irradiation-induced effects in PET films show that comparison of UV-vis transmission spectra before and after annealing can provide information about the structure of deep traps in PET.

Irradiated polyethylene terephthalate and fly ash based grouts for semi-flexible pavement: design and optimisation using response surface methodology

ABSTRACT This study explores the effectiveness of using recycled irradiated waste polyethylene terephthalate (PET) as a partial replacement for cement in the formulation of cementitious grouts. This study investigates the impact of regular and irradiated PET and fly ash (FA) on the flowability, drying shrinkage, compressive strength and flexural strength of cementitious grouts. It was observed that partial replacement of cement with normal PET (in the range of 5–10% by mass of cement) resulted in a reduction (between 26% and 46%) in compressive strength of the cured grout. Interestingly, the use of irradiated PET instead of regular PET restores 8–22% of the compressive strength. Additionally, response surface methodology (RSM) is used to design the experiments, analyze the responses, and optimise the independent variables. A high R 2 and adequate precision of the ANOVA is an indication of a good agreement between the factors and responses. Besides, gamma irradiation makes it possible to use a higher percentage of 2.57–4.75% waste PET as cement replacement while retaining the target flow and strength properties. Therefore, the proposed treatment of PET with gamma radiation could be an effective way for recycling waste PET and a significant step towards achieving the zero-waste challenge.

Design optimization and statistical modeling of cementitious grout containing irradiated plastic waste and silica fume using response surface methodology

This study discusses the influence of replacing ordinary Portland cement (OPC) with irradiated waste polyethylene terephthalate (PET) and silica fume on fresh and hardened properties of cementitious grouts. The effect of PET (normal and irradiated) and silica fume (SF) on flow, drying shrinkage, compressive strength (1-day, 7-days and 28-days) and flexural strength (28-days) of cementitious grouts were investigated. Additionally, an analytical tool response surface methodology (RSM) was used for designing the experiment and statistically analyzing the experimental results. A microstructural investigation was performed on the grout sample by using FESEM with EDX and XRD analysis. Experimental results show that loss in both compressive and flexural strengths was observed when OPC was partially replaced by normal PET, however, some of these strengths were gained back by incorporating irradiated PET. A slight reduction in drying shrinkage was observed with the addition of both normal PET and irradiated PET as compared to control samples. The microstructural investigation results also show that the addition of irradiated PET in cement grout causes the formation of new and unique phases, which help in the densification and refinement of microstructure. The theoretical results from the ANOVA model using RSM analysis were experimentally validated with an error of <5%, and hence, good agreement was observed between theoretical and experimental results. Gamma irradiation of PET showed the possibility of using plastic waste as a potential source of raw material for the construction industry.

Irradiated polyethylene terephthalate fiber and binder contents optimization for fiber-reinforced asphalt mix using response surface methodology

This paper presents the volumetric and Marshall Stability characteristics of irradiated waste polyethylene terephthalate fiber-reinforced asphalt mix utilizing the analysis of variance. Exposing polymers to gamma radiation boosts its mechanical and thermal properties which have a direct impact on improving its strength. The influences of irradiated fiber and binder contents on the volumetric and strength properties have been identified via response surface methods (RSM). The RSM was used to determine the optimized contents of irradiated fiber and binder through central composite design (CCD). The results indicate that the interactions between the two independent variables are both influential. The high values of the coefficient of determination (R2) show a good agreement between the actual and predicted values. The numerical optimization elucidates that the optimal irradiated fiber and binder contents were 0.53% and 5.25% respectively. The absolute percent errors between the actual and predicted values were observed to be less than 7% for all the responses.

Application of gamma irradiation on Polyethylene Terephthalate (PET) for use in asphaltic concrete mixtures as aggregates replacement

Polyethylene Terephthalate (PET) is one of the most commonly available kinds of plastic present in the municipal solid waste and it is a non-biodegradable semi-crystalline thermoplastic polymer, studied as polyester material. This paper intends to assess impacts of using PET (regular and irradiated) as aggregate that would replace by volume of equal size (10.00-5.00mm) in asphalt blend on the engineering properties of dense graded asphaltic concrete. The volumetric and mechanical properties of the blends incorporating different percent of PET (0, 5, 10, 15 and 20) were determined. In all mixtures, 5.0% optimum bitumen content was utilized. The outcome revealed that aggregate substitution of 10% (equivalent to 2.4% by weight of total mix) with irradiated PET result in optimum Marshall Stability and flow value of 3.6mm. It also showed that mixes with irradiated PET at 100kGy radiation dose have Marshall Stability values higher than mixes with same contents of regular PET. The finding also shows that the addition of PET and utilization of gamma radiation has a critical constructive outcome on the properties of asphalt concrete mixes as the stability increases for mixes with irradiated PET when compared with mixes with regular PET (RPET).

Structural and Mechanical Strength of Proton Radiation Processed Polyethylene Terephthalate

The change in structural and mechanical behavior of polyethylene terephthalate (PET) due to 2.4 MeV proton has been studied. Radiation processing of PET polymer is carried out using different low doses such as 0.2, 2.0, and 20 kGy. The Physics of microstrain and radiation-induced mesophase formation are analysed. X-ray investigation indicates that proton-induced structural modification takes place in the material. Apart from usual diffraction peaks, a low intensity broad peak is observed at small angle of about 2q =10º, when the fibre axis is mounted parallel to the X-ray direction. Such peak is absent in the diffraction spectrum when the fibre axis is mounted perpendicular to the beam direction. The appearance of the extra peak in a particular orientation confirms that, the phase is 2-dimensionally oriented (mesophase). The Young’s modulus (Y) of this irradiated PET sample is found to be more than that of the virgin sample with the highest value recorded for a dose of 2.0 kGy. The decrease in Y for higher dose (20 kGy) may be due to enhanced ion-induced microstrain in the sample, causing degradation in mechanical strength.

Effect of Irradiated and Non-Irradiated Waste PET Based Cementitious Grouts on Flexural Strength of Semi-Flexible Pavement.

In this study the effect of irradiated and non-irradiated waste polyethylene terephthalate (PET) as replacement of cement and fly-ash in ordinary Portland cement (OPC) and geopolymeric cement (GPC) based cementitious grouts on flexural strength of semi-flexible pavement specimens were evaluated. The porous asphalt gradation was selected based on Malaysian specifications for semi-flexible pavements with a target of 30% air voids. The cement content in the OPC grouts and the fly-ash content in the GPC based grouts were partially replaced with 1.25% PET (using both irradiated and non-irradiated PET). Beam specimens were prepared and tested for flexural strength properties using center point loading configuration. The grouts modified with recycled waste plastic (PET) showed approximately the same results as obtained from the control specimens. Although the replacement amount was low (1.25% by weight of cement), nonetheless, significant impact on reducing CO2 emissions is expected when preparing grouts for mass construction of semi-flexible pavement surfaces. Similarly, effective recycling of waste plastics in road construction and replacing OPC with plastic and geopolymers will have a positive effect on the environment and will furthermore contribute to sustainable pavement construction.

Investigation of Ionic Transport Through Track-Etched Conical Nanopores of PET Membrane

The control of ionic transportation inside the multi asymmetric conical nanopores in polyethylene terephthalate (PET) membrane was investigated. The conical nanopores were prepared by chemical etching in irradiated PET foil using etchant (9 M NaOH) and stopping solution (1 M NaCl [Formula: see text] 1 M HCOOH). The behavior of ionic current was recorded under stepping voltage [Formula: see text]2[Formula: see text]V to [Formula: see text]2[Formula: see text]V at different molar concentrations of potassium halides (KCl, KBr and KI) under symmetric bathing condition in electrochemical cell. It is found that the presence of multiple ionic species and the occurrence of counterion condensation of charge regulated polyelectrolyte play an effective role in ionic current rectification (ICR). The electrical conductance of conical nanopores may be estimated by measuring the ionic current rectification properties of track-etched nanopores. The charge transport properties vary with molar concentration and pH of electrolyte. Moreover, ICR may be used as a voltage gating phenomena with wide technological applications.

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

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 NaBH4 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 (L9(3)4) for Cu-Co-P coating as follows: CoSO4·7H2O addition of 0.08M, pH value, plating temperature and time were set on 10.0, 35°C and 25min, respectively. Under the optimal conditions, copper polyalloy possessed high adhesive strength and the lowest surface resistance (8.06Ω/sq), while maintaining reliability even after over 1000 times of bending and mechanical stress. The results of scanning electron microscope (SEM) and atomic force microscope (AFM) measurements showed that Cu-Co-P layer formed on PET surface was imparted with fine uniformity and high compactness. Electrochemical test revealed the optimized Cu-Co-P coatings exhibited high corrosion resistance in NaCl, NaOH and HCl solutions, respectively. The excellent electromagnetic interference shielding effectiveness (EMI SE >99.999% at frequency ranging from 30MHz to 1000MHz) of copper polyalloy/PET composites was confirmed by the spectrum analyzer. Therefore, this copper polyalloy will have potential applications in microelectronics packaging and coatings for anti-corrosion and electromagnetic interference shielding.

Structural and electrical properties of tracks of heavy ions in polyethylene terephthalate and mica

An image of the entrance of high-energy ions of krypton, xenon, and bismuth on the surface of polyethylene terephthalate (PET) and mica is obtained. It is shown that in both cases the tracks have the appearance of protuberances. The formation of protuberances is associated with the destruction of material in the region of the track, the formation of amorphous structure, and the removal of low-molecular-weight radiolysis products as gaseous substances. Storage of the irradiated PET samples in water and a weak alkaline solution for several hours changes the surface topography due to hydrolysis of the material and the removal of radiolysis products into the solution. The kinetics of etching tracks in a weak alkaline solution and the formation of pores are studied. The stream function, electrical resistance, and permeability of the tracks in KCl, LiCl, MgCl2, and BaCl2 electrolytes are measured. The surface charge of the tracks is calculated from these values.

NEXAFS study of electron beam irradiated PET

One of the most promising methods for surface property modification is electron beam irradiation, which can create new chemical groups on surfaces. In this study we investigated the surface functionalisation of polyethylene terephthalate (PET), a commonly used polymer material with many applications. The changes in surface properties were examined after electron beam irradiation with near edge X-ray adsorption fine structure (NEXAFS). The angle dependent NEXAFS spectra measured at the C K-edge of PET exhibit good directionality with a tilting angle α of 31.0°. As the duration of the electron beam irradiation is increased, new chemical bonding is induced on the surface and the angle dependence of PET disappears, which are results of the breaking of the C=C π* bonds.