Radiation Polymerization Research Articles

Using femtosecond laser pulses to explore the nonlinear optical properties of a CR-39 polymer after being exposed to alpha particles

The effect of alpha particle radiation on nonlinear optical properties of poly(allyl diglycol carbonate) (CR-39) polymer has been investigated using the Z-scan technique. CR-39 polymers were exposed to alpha particles at different doses: 23.7 and 47.5 Gy. Alpha particles cause significant optical and chemical changes in the polymer CR-39. Data from UV-visible spectrometers revealed that when alpha particle doses increased, the absorption edge of polymer redshifted and the energy band gap decreased. Fourier transform infrared absorption spectra of alpha irradiation samples show a change in intensity and bond breakage in the chemical groups constituting the CR-39 polymer compared to the pristine one. With 100 fs laser pulses and 80 MHz repetition rate, the nonlinear absorption coefficient and nonlinear refractive index are measured for a pristine and irradiated polymer with different alpha doses at different excitation wavelengths and laser peak power. The samples displayed a negative nonlinear refractive index and reverse saturable absorption behavior with three photons absorption. The results reveal that the nonlinear optical properties of CR-39 were enhanced by alpha particle radiation.

Comparative Study of Impact of Gamma and MeV Ion Irradiations on Electrical and Optical Properties Polystyrene/Eu2O3 Nanocomposites.

In the present study, the effect of gamma irradiation and 90 MeV carbon ion beam irradiation on electrical properties and optical of Polystyrene/Eu2O3 nanocomposites at different fluences were examined. Modified electrical and optical responses of polymer nanocomposites were investigated using Impedance, Photoluminescence and UV-VIS spectroscopies. FTIR analysis shows a reduction of various modes of molecular vibrations caused by 90 MeV carbon ion beam irradiation. The polymer nanocomposites change into a graphite-like structure upon both kinds of irradiations as evidenced by the decrease in the optical band gap. The photoluminescence emission spectra show three characteristic peaks of Eu3+ ions, when excited at 247 nm wavelength. It emits intense red light suggesting its potential for usage in LED technology. The peak intensity of PL emission spectra is enhanced after ion beam irradiation and is because of the formation new radiative combination; however, it decreases upon gamma irradiation. Dielectric responses of pristine and irradiated polymer nanocomposites were studied over the frequency range of 100 Hz to 100 kHz using LCR meter. There appears a significant improvement in the dielectric response as a result of structural changes in both types of irradiations. AFM images show that the film becomes smoother upon both types of irradiations.

Neutral polymer-pseudo polyelectrolyte transition of a post irradiated polymer dissolved in water

The purpose of this study is to study the conformation transition of a post irradiated polymer dissolved in water. In fact, polyvinylpyrrolidone (PVP) in powder(Mw = 1.300.000 g/mol), is irradiated with various doses, D, ranged from 0.3 to 50 kGy of 60Co-gamma. The irradiated polymer, PVP*, is dissolved in water to obtain post irradiated solutions of different concentration. After the stabilization of the obtained solutions (48 h), refractometry and viscosity measurements, are used to characterize the post irradiated aqueous solutions at 25 °C. The specific volume of PVP* dissolved in water was determined according modified Lorentz-Lorenz and Gaston-Dale equations, showing two dependence on the dose, D. For D ≤ Dc = 20 kGy, the specific volume increases and for D ≥ Dc, the specific volume decreases. The reduced viscosity of PVP*(Mw = 1.300.000 g/mol) aqueous solution permits to delimit the dilute and semi dilute regimes concentration and deduce the overlapping concentration, C*PVP*(D), which found to be insensitive to the dose value. For D < Dc, the intrinsic viscosity PVP* dissolved in water is determined according a modified Huggins equation and so the irradiated polymer behaves as neutral polymer. However, when D = DC the intrinsic viscosity values calculated according modified Fuoss and Fedors equations are very close and the irradiated polymer behaves as a polyelectrolyte in water. For D > Dc, the modified Fedors equation describes perfectly the evolution of the reduced viscosity versus irradiated polymer concentration. So, PVP* behaves as a polyelectrolyte in water and a neutral polymer – pseudo polyelectrolyte transition occurs under gamma irradiation effect. The irradiated polymer molar mass, MwPVP∗(D), was determined by comparing its intrinsic viscosity to these established according the Mark Howink Shakurada equation. MwPVP∗(D) decreases by increasing the dose value, which confirm the scission the polymer chain under gamma irradiation effect.

Modification of gamma transmittance at gamma dose absorbed flexible poly (imide siloxane) block copolymer with high thermal performance feature

ABSTRACT Flexible poly (imide siloxane) block copolymer (which was not adhesive feature) was exposed to gamma radiation at 10 kGy by using a certified Co-60 radioisotope for the evaluation of its optimum application condition in gamma irradiation fields with high dose. High gamma dose application has caused to display tuneable high-temperature features as the result of its density development due to radiation hardness effect at 10 kGy. The development of the polysilicon-11 crystallites has caused a decrease in the penetration of gamma photons at the irradiated flexible copolymer due to the gamma absorbed dose. The elimination of the agglomeration by high gamma dose application has assisted the development of the grainy surface at the irradiated flexible copolymer with a more homogeneous structure. The development of the gamma shielding performance of the irradiated polymer has explained the optimum synthesis conditions for the solution of the gamma dose problems at high-temperature applications in contact with the contoured surface (including different heights, depths curvatures on the surface and presenting importance in radiation shielding design and engineering) at high gamma dose areas. A comparison of penetration deepness of gamma photons has indicated its performance (at 0.662 MeV by using the Cs-137 radioisotope and at 1.25 MeV by using the Co-60 radioisotope by using the gamma transmission technique) to determine the details about the density variations of this polymer. The hybrid copolymer was improved to support the development of polymeric instruments for new trend applications in computing and artificial intelligence, biotechnology, and internet of things (for smart monitoring and sensing technology).

Synthesis, Swelling, Diffusion and Cationic Dye Adsorption Studies of Semi‐IPN Sodium Alginate/ Poly(HEMA‐co‐MA) Hydrogels

AbstractIn this study, the novel pH‐sensitive s‐IPN consist of sodium alginate integrated with poly(HEMA‐co‐MA) hydrogel matrix are prepared by using two‐step methodology. In the first step, 2‐hydroxyethyl methacrylate (HEMA)/maleic acid (MA) copolymeric hydrogels are prepared by gamma radiation polymerization. Then, poly(HEMA‐co‐MA) hydrogel was immersed in sodium alginate solution (SA) and finally gamma radiation polymerization was carried out. The swelling, pH‐sensivity and diffusion properties of the prepared s‐IPN gels in deionized water and in dye solutions were investigated. Methylene Blue (MB) was used as a model dye. MB adsorption capacities of the hydrogels were found to be 0.26, 0.40 and 13.77 mg MB/g dry gel in PHEMA, P(HEMA‐co‐MA) and s‐IPN SA/P(HEMA‐co‐MA) hydrogels, respectively. MB release data was fitted to various kinetic models to study the dye release behavior. The MB release from all the prepared hydrogels fitted the Korsmeyer‐Peppas model. Swelling, diffusion and MB adsorption properties of the new s‐IPN hydrogel were improved with the inclusion of SA and MA in the gel structure.

Preparation and Application Progress of Imprinted Polymers.

Due to the specific recognition performance, imprinted polymers have been widely investigated and applied in the field of separation and detection. Based on the introduction of the imprinting principles, the classification of imprinted polymers (bulk imprinting, surface imprinting, and epitope imprinting) are summarized according to their structure first. Secondly, the preparation methods of imprinted polymers are summarized in detail, including traditional thermal polymerization, novel radiation polymerization, and green polymerization. Then, the practical applications of imprinted polymers for the selective recognition of different substrates, such as metal ions, organic molecules, and biological macromolecules, are systematically summarized. Finally, the existing problems in its preparation and application are summarized, and its prospects have been prospected.

In Situ Solidification by γ−ray Irradiation Process for Integrated Solid−State Lithium Battery

The safety concerns associated with power batteries have prompted significant interest in all−solid−state lithium batteries (ASSBs). However, the advancement of ASSBs has been significantly impeded due to their unsatisfactory electrochemical performance, which is attributed to the challenging interface between the solid−state electrolyte and the electrodes. In this work, an in situ polymerized composite solid−state electrolyte (LLZTO−PVC) consisting of poly(vinylene carbonate) (PVC) and Li6.4La3Zr1.4Ta0.6O12 (LLZTO) was successfully prepared by a γ−ray irradiation technique. The novel technique successfully solved the problem of rigidity at the interface between the electrode and electrolyte. The LLZTO−PVC electrolyte exhibited a notable ionic conductivity of 1.2 × 10−4 S cm−1 25 °C, along with good mechanical strength and flexibility and an electrochemical window exceeding 4.65 V. It was showed that the LiCoO2(LCO)/LLZTO−PVC/Li battery, which achieved in situ solidification via γ−ray irradiation, can steadily work at a current density of 0.2 C at 25 °C and maintain a retention rate of 92.4% over 100 cycles. The good interfacial compatibility between electrodes and LLZTO−PVC electrolyte designed via in situ γ−ray irradiation polymerization could be attributed to its excellent electrochemical performance. Therefore, the method of in situ γ−ray irradiation polymerization provides a vital reference for solving the interface problem.

A novel anti-washout curing solution of calcium phosphate cement prepared via irradiation polymerization.

The anti-washout ability of calcium phosphate cement (CPC) determines its effectiveness in clinical application. In the current research, the common method for improving the anti-washout ability of CPC is to add anti-washout polymer agents. Sodium polyacrylate powder is an excellent anti-washout agent but when bonded with CPC it basically degrades the anti-washout performance of CPC after γ-ray irradiation, and is widely used in the sterilization process of CPC products. Therefore, we propose a method for the preparation of a sodium polyacrylate solution through irradiation polymerization as curing solution for CPC. This method first uses γ-ray irradiation sterilization to improve the anti-washout ability of CPC directly. It not only avoids the adverse effects of γ-rays on anti-washout agents, but also the CPC blended using this sodium polyacrylate solution had good biological properties and injectability. It provides a new method for promoting the anti-washout properties of calcium phosphate cement, which is of great significance for expanding the clinical application of CPC.

Effect of UV Radiation on Dissipative Processes in Polyacrylates of Different Elasticities

Dynamic mechanical relaxation spectroscopy is used to study the relaxation behavior of elastic alkyl(met) polymers. The items of interest are acrylates on metal substrates before and after UV irradiation of different durations. Analysis is based on comparing the intensity of local dissipative relaxation in irradiated and non-irradiated polymers, along with their glass transition temperatures and elastic properties.

Transparent ionic conductive elastomers with high mechanical strength and strong tensile properties for strain sensors.

Stretchable ionic conductive elastomers have been extensively studied due to their great application potential in the fields of sensors, batteries, capacitors and flexible robots. However, it is still challenging to prepare multifunctional ionic conductive elastomers with high mechanical strength and excellent tensile properties by a green and efficient method. In this study, we prepared PDES-DMA ionic conductive elastomers by a "one step" rapid in situ polymerization of AA/ChCl-type polymerizable deep eutectic solvents (PDES) and N,N-dimethylacrylamide (DMA) under ultraviolet (UV) irradiation. In addition to the characteristics of high mechanical strength (tensile strength of 9.27 MPa) and excellent tensile properties (elongation at break of 1071%), the PDES-DMA elastomer also has high transparency (>80%), strong self-adhesion (adhesion strength with glass surface 133.8 kPa) and self-healing properties. In addition, sensors based on the ionic conductive elastomer can be used to detect human movements such as finger, wrist, elbow, ankle and knee bending. Considering the convenience of the preparation method and the excellent versatility of the prepared PDES-DMA ionic conductive elastomer, we believe that the method proposed in this study has potential application prospects in the field of flexible electronics.

Janus-type ionic conductive gels with single-sided adhesiveness prepared by a “one-step” method for strain/pressure sensors

Janus-type ionic conductive gels with single-sided adhesiveness were successfully prepared by “one-step” UV irradiation polymerization for strain/pressure sensors.

On a radiolytic origin of red organics at the surface of the Arrokoth Trans-Neptunian Object

The classical Kuiper Belt Object (KBO) Arrokoth was surveyed by the New Horizons spacecraft on 1st January 2019, revealing a small bilobed object with a red surface, whose spectral slope lies in the average of the whole KBOs population. This red color has been assigned to reddish organic materials, either inherited from the protosolar disk during accretion, or formed through radiolytic processes in the surface due to exposure to solar or interstellar photons, Solar Wind, Solar Energetic Particles or Galactic Cosmic Rays. We report here a study investigating the radiolytic scenario, based on numerical calculations and experimental simulations run with swift heavy ions (74.8 MeV 136Xe19+ and 33.06 MeV 58Ni9+), and low-energy 105 keV 18O6+ ions on CH3OH ice, the only molecule identified at Arrokoth’s surface. Calculations show that sputtering is essentially controlled by Solar Wind (H and He), and that the sputtering rate depends on the nature of the material: erosion thickness over 4.55 Gyr are a few micrometers for amorphous carbon (as an analog of red organics) and a ∼240μm to around ∼10 mm for H2O and CO ice, respectively. Chemistry within the subsurface is essentially controlled by Galactic Cosmic rays (H and He), which penetrate deep down to several tens of meters and deliver an electronic dose higher than 1 eV.atom−1 in the first meter. The electronic and elastic doses delivered by Solar Wind ions are limited to the first 10s nm of the top surface, but Solar Energetic Particles deliver high electronic doses in the first 100μm of the surface (up to 200 eV.atom−1). Experimental simulations show that irradiating methanol ice with a dose consistent with that in planetary conditions, results in the formation of reddish organic materials made of aliphatic, conjugated and unconjugated olefinic, acetylinic, carbonyl and hydroxyl groups. A similarity with irradiated simple polymers (e.g. polyethyleneglycol) and materials formed through cold plasma experiments (tholins) is observed. There is little dependence with the nature and energy of the ion. The residue recovered at room temperature was analyzed with High Resolution Mass Spectrometry (Orbitrap), revealing a complex composition with around 6596 chemical formulas and likely several tens of thousands of molecules. Altogether, these analyses support active polymerization mechanisms similar to those observed in irradiated polymers, as bond-breaking, cross-linking or formation of olefinic bonds through recombination of radicals in adjacent carbon atoms. Considering both sputtering and radiolysis, as well as material ablation due to dust bombardment reported in literature, a scenario is taking shape as the production of reddish organics deep in the subsurface, and the settling of an organic crust at the top surface through volatiles removal. The presence of methanol and absence of water, inconsistent with sputtering fractionation, remains unexplained.

Study of the Recoil Impulse of Gaseous Products of IR Laser Ablation of Polystyrene and Polystyrene/Carbon Nanotubes Composite Obtained by Radiation Polymerization of Styrene

Study of the Recoil Impulse of Gaseous Products of IR Laser Ablation of Polystyrene and Polystyrene/Carbon Nanotubes Composite Obtained by Radiation Polymerization of Styrene

Morphological, Photochemical and Spectroscopic Studies of Ibuprofen-Tin Complexes

Poly(vinyl chloride) (PVC) was prepared and the photo-stabilization of polymer films was studied using ultraviolet (UV) light. The efficiency of the synthesized polymer complex of ibuprofen-tin which is the photo-stabilizer in this study afterward of 300 hours of irradiation were evaluated by calculate the constant of PVC degradation rate. The outcome of this research has shown that the additives (ibuprofen-tin complexes) effect significantly on the decreased degradation constant compare to blank PVC, without additives the rate of degradation constant of PVC is greater than when the additives are added. The surface morphologies of the irradiated polymer film with additives were researches utilizing Field Emission Scanning Electron Microscope (FESEM). It can be seen that the polymer film with added additives is less roughness than the irradiated PVC (blank). The organotin complexes behave in this study as a photostabilizer to maintain the PVC from any decomposition by absorbing the incident light and convert it over the time as a heat to the polymeric chain.

The Impact of Temporal Changes in Irradiated nMAG Polymer Gels on Their Applicability in Small Field Dosimetry in Radiotherapy.

As advanced radiotherapy techniques progress to deliver a high absorbed dose to the target volume while minimizing the dose to normal tissues using intensity-modulated beams, arcs or stereotactic radiosurgery, new challenges occur to assure that the high treatment dose is delivered homogeneously to the tumor. Small irradiation field sizes (≤1 cm2) that tightly conform to precise target regions and allow for the deliverance of doses with a high therapeutic ratio, are of particular interest. However, the small field dosimetry using conventional dosimeters is limited by the relative large size of the detector. Radiation-sensitive polymer gels have the potential to meet this dosimetry challenge due to their almost unlimited ability in resolving three-dimensional dose distributions of any shape and makes them unique and suitable for the evaluation of dose profiles and the verification of complex doses. In this work, dose distributions in nMAG gels that have been irradiated to different doses by applying a 6 MV FFF photon beam collimated to 1 cm2, were analyzed and the dose profiles were evaluated by applying a gamma passing rate criteria of 3%/3 mm and considering different post-irradiation time intervals between the irradiation and the gels read out process. X-ray CT and NMR imaging procedures were used for the dose evaluation. It was found that the shape and uniformity of the dose profiles were changing due to post-irradiation polymerization and gelation processes, indicating time dependent growing uniformity which was better expressed for the higher delivered doses. It was estimated that in order to obtain acceptably symmetric small field dose profiles, a longer post-irradiation time is needed for getting the full scope of the polymerization as compared with the recently recommended 24 h period between irradiation and the read out processes of the dose gels. An estimated overall uncertainty (double standard deviation, 95% confidence level) of 3.66% was achieved by applying R2 measurements (NMR read out), and a 3.81–applying X-ray CT read out for 12 Gy irradiated gels 56 h post-irradiation. An increasing tendency for the uncertainty was observed with a decreasing post-irradiation time. A gamma passing rate of 90.3% was estimated for the 12 Gy irradiated gels and, 56 h post-irradiation, the X-ray CT evaluated gels as well as a gamma passing rate of 92.7% was obtained for the NMR evaluated gels applying a 3%/3 mm passing criteria.

Performance improvement of polymer concrete produced with unsaturated resin, by a post-cure process, polyester fibers and gamma radiation

As it is known, production of polymer concrete contemplates polymer resins as main component, for example polyester or epoxy; as well as mineral aggregates, including silica sand and marble. However, it is not common to add polymer fibers, because these sometimes decrease the mechanical properties. Thus, they need some physical or chemical modifications for acting as reinforcements. For these reasons, in a first experimental stage polymer concrete was produced with 30 wt% polyester resin and 70 wt% marble, at room temperature. Then, polymer concrete was elaborated with the same resin concentration, but the marble concentration was substituted partially by adding 0.1, 0.3 and 0.5 wt% of polyester fibers. After, these polymer concretes with fibers as well as those without fibers were exposed to gamma rays at 10, 50 and 100 kGy doses. Finally, the non-irradiated and irradiated polymer concretes were mechanically tested in compression. The second experimental stage consisted to produce the same type of polymer concretes described in the first stage, but now applying to each one of them, a post-cure process consisting to heating at 80 °C during 8 h. The results show increase up to 182% on the deformation and slightly decrease on compressive strength and elasticity modulus, for polymer concretes containing fibers and irradiated. While, for post-cured polymer concretes, the deformation increased up to 194% and the compressive strength up to 8.2%, but the elasticity modulus decreased. Such mechanical improvements were related with the superficial and thermal modifications on the polyester fibers produced by gamma rays.

Characteristics and radiolysis behavior of polyvinylchloride under accelerated proton and γ-irradiation

The effect of high energy protons and γ-irradiation on the structural properties, surface-energies, and toxicological properties of polyvinyl chloride (PVC) were studied due to the role PVC products play in many technologies including the nuclear industry. Accelerated 1–4 MeV protons impacting on PVC in vacuum lead to the formation of polyenyl radicals as shown by EPR and to an increase in free surface energy due to functionalization of the surface of the irradiated polymer. γ-irradiation leads to the formation of unsaturated bonds, carbonyl and hydroxyl groups as shown by IR and to the release of HCl. Correlated molecular orbital theory calculations of reaction thermodynamics were used to aid in the development of a mechanism in the absence of oxygen. The formation and accumulation of chromophores and auxochromic groups during γ-radiolysis of PVC leads to a gradual change of the initial white color of the polymer to yellow and then to brown and black with high sensitivity. A mixture of powdered PVC and silicate glue was used to determine the profile of a 60Co γ-radiation beam on targets with a complex relief. γ-irradiated polymer does not have a local irritating effect due to a single application to the skin of mice in an adhesive mixture at a concentration of up to 5000 mg/kg. γ-radiolysis of PVC powder in air with a dose of up to 1400 kGy does not affect its acute toxicity when administered intragastrically to BDF1 mice. PVC and its γ-irradiated analogs are non-toxic at doses ≤5000 mg/kg.

Optical properties of polymerization N-(3-methoxypropyl) acrylamide polymer gel dosimeters for radiotherapy

PurposeThe purpose of this paper is to evaluate the dosimetric properties of N-(3-methoxypropyl) acrylamide (NMPA) polymer gel dosimeter using UV-vis spectrophotometry as a simple and low-cost method.Design/methodology/approachThe gel samples have been irradiated to various doses using a medical linear accelerator with 6 MV beam energy. The optical density of un-irradiated and irradiated NMPA polymer gel dosimeters in terms of absorbance at 500 nm was investigated by UV-vis spectrophotometry.FindingsThe absorbance values of the gel samples were increased linearly with increasing dose in the dose range between 2 and 20 Gy. A remarkable improvement in the dose response was noticed after the addition of various concentrations of glycerol. The impact of dose rate, beam energy and the post-stability of the exposed gels was studied and found consistent with the previous study using nuclear magnetic resonance results (energy independent and dose rate independent, stable up to one week).Practical implicationsThe results of the independent experimental spectrophotometry and nuclear magnetic resonance analyses indicate that the NMPA polymer gel dosimeter has good and consistent dosimetric features for radiotherapy dosimetry.Originality/valueThe ionizing radiation-induced polymerization of gel samples leads to a change in the absorbance of the irradiated gel samples. This study introduces the first characterization of NMPA gel dosimeter by means of UV-vis spectrophotometer.

Temperature-Dependent Changes in Gamma Irradiated Porcine Gelatin with Low Bloom (PGL) Value: an ESR Investigation

Gamma irradiation of Gelatin brings important changes in its chemical structure, making it suitable for different applications. The irradiated Gelatin may be subjected to different thermal treatments during these applications. Therefore, temperature-dependent changes in irradiated gelatins are a point of interest. Electron spin resonance (ESR) is vital for detecting free radical processes in irradiated polymers. As such, ESR spectra of temperature-dependent porcine Gelatin with low bloom are recorded, and they are analyzed by computer simulation techniques. Component spectra under different conditions are evaluated by the magnetic parameters employed to simulate the ESR spectra. The results indicate that the spectral shape at 300 K (RT) is stable up to 350 K, and signal intensity begins to decay beyond 350 K. The signal vanished around 355 K, designated as radical decay temperature. Bloch analysis is applied to evaluate activation energy associated with free radical decay, calculated around 35 KJ/mole.

Fluorine‐free superhydrophobic meshes decorated with porous microspheres for highly efficient oil–water separation

AbstractIn this study, we report a new facile method to prepare fluorine‐free superhydrophobic separation films by deposition of micron‐sized hydrophobic polyhigh internal phase emulsion (polyHIPE) microspheres on stainless steel meshes. The so‐called polyHIPE microspheres are polymer ones with interconnected porous structures, which are prepared by γ‐ray radiation polymerization of (W/O HIPE)/W double emulsions stabilized by a single emulsifier 12‐acryloyloxy‐9‐octadecenoic acid using a one‐step emulsification in this work. The oil–water separation results show that our self‐made hydrophobic meshes have excellent oil–water separation efficiency (about 99.5%), outstanding permeation flux (no less than 187.5 L/[m2·min] and the maximum value of 1850 L/[m2·min]). The oil flux of common organic solvents, water contact angle and water intrusion pressure of these hydrophobic meshes can be readily tuned by changing the size, amount and composition of polyHIPE microspheres. It is worth noting that the superhydrophobic meshes remain excellent separation efficiency and stability after 10 cycles in corrosive environments. More importantly, these superhydrophobic meshes can also efficiently separate surfactant‐stabilized water‐in‐oil emulsions. The polyHIPE microspheres decorated superhydrophobic meshes that can easily realize large‐scale production have potentially practical applications in sewage treatment or separation/purification.