Poly Allyl Diglycol Carbonate Research Articles

Dependence of Structure Variation, Pyrolysis, and Nonlinear Optical Dispersion on the Chemical Etching of Poly Allyl Diglycol Carbonate (PADC) Irradiated with $${\alpha}$$-Particles

Dependence of Structure Variation, Pyrolysis, and Nonlinear Optical Dispersion on the Chemical Etching of Poly Allyl Diglycol Carbonate (PADC) Irradiated with $${\alpha}$$-Particles

PC12 differentiation to neuron cells activated by a low-level laser at 660 nm on UV pre-treated CR-39 scaffolds with parallel microchannels.

The lack of regeneration of injured neurons in the central and peripheral neural system leads to the failure of damaged tissue repair in patients. While there is no definitive cure for most neurodegenerative diseases, new therapeutic methods that cause the proliferation and differentiation of neurons are of interest. Challenges such as the inability of neuronal cells to proliferate after injury, the lack of a stimulus for initial stimulation, and the presence of the microenvironment around CNS neurons contain several inhibitory factors that prevent neuron regeneration, thus, creating a structure similar to the extracellular matrix helps the cell proliferation in current treatment. A rapid method of neuron-like cell differentiation of PC12 cells is introduced here based on a novel synthetic scaffold. Initially, poly allyldiglycol carbonate (CR-39) substrate is textured under a high dose of ArF UV excimer laser (1000 shot, 300 mJ/pulse equivalent to 300 J/cm2 at 193 nm) to create superficial periodic parallel microchannels with the micrometer spacing and sub-micron width. Ultraviolet treated CR-39 (UT CR-39) provides a suitable scaffold to speed up the transformation/differentiation of PC12 cells. The latter is pheochromocytoma of the rat adrenal medulla as an embryonic origin from the neural crest usually exposed to the nerve growth factor (NGF). In fact, PC12 cells are seeded on the microchannels and simultaneously are stimulated by coherent red photons at 660 nm within the therapeutic window. The UT CR-39 scaffold undergoes extra improvement of ∼ 30% after 12 minutes of laser activation regarding the photo-biomodulation (PBM) mechanism. The cell activation due to the coherent photons also gives rise to enhanced proliferation/differentiation. Here, PC12 cells are efficiently differentiated into neurons according to immunocytochemistry (ICC) and Western Blot verification tests based on MAP2 and synapsin-1 protein expression. In general, UT CR-39 acts as a superior bed to elevate the population of neuron-like cells up to threefold against those of untreated (control)ones. We conclude that the surface cross-linking due to UV exposure and subsequent induced hydrophilicity notably contribute to the neuron-like cell differentiation of PC12 without adding NGF.

Efficient Preparation of Poly(allyl diglycol carbonate) (PADC) Nuclear Track Detectors: UV Photopolymerization.

The decay of radon gas in soil and buildings produces alpha radiation, which is the second leading cause of lung cancer in humans. Therefore, by conveniently detecting radon gas in the environment, potential sources of danger can be identified early, and necessary measures can be taken to protect human health. Solid-state nuclear track detectors prepared from polyallyl diglycol carbonate (PADC) resin are the most sensitive detectors for alpha radiation released by radon gas. The traditional method of preparing PADC resin involves free radical thermal polymerization, which suffers from issues such as low polymerization efficiency, long processing time, and the occurrence of defects in the product. In this study, PADC resin was efficiently prepared using a UV initiator. Starting from the polymerization mechanism, experiments were designed using a controlled variable approach, and a rational polymerization apparatus was devised. By comparing the double bond conversion rate, transparency, hardness, and yellowness index of the polymers, the optimal initiator for PADC resin, 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), was selected. The influence of irradiation intensity, irradiation time, and UV initiator dosage was investigated. The performance of the polymers, including double bond conversion rate, optical properties, dynamic mechanical properties, etching rate, and track detection efficiency, was analyzed. The experimental conditions for preparing PADC resin were optimized: irradiation intensity of 12 mW/cm2, irradiation time of 25 min, and UV initiator dosage of 5 parts. The resulting resin polymer had a double bond conversion rate of 93.2% and a track detection efficiency of 0.714.

Structural degradation of polyallyl diglycol carbonate (PADC) polymer: analytical characterization and simulation studies

A comprehensive study has been carried out to understand the details of structural modifications of polyallyl diglycol carbonate (PADC) polymer under the effects of different external factors. Synergistic effect of heat treatment with radiation on the polymer structure was studied. Incorporation of a neutral chromophore to understand the structural changes was attempted. Theoretical simulations were applied to get insight into the detailed aspects of structural modifications. Diverse techniques were used to characterize the samples and compare with the results of simulation studies.

Study of poly allyl diglycol carbonate Kinetics treatment induced by ultrasonic frequency plasma

This research reveals the possibility of altering the structural, surface, fluorescence, and optical characteristics of CR-39 polymer detector by the effect of Ultrasonic frequency (UF) plasma argon gas. The samples were exposed to the plasma at different times ranging from 20 min to 100 min. Fourier Transform Infrared (FTIR) Spectroscopy, contact angle goniometer, surface roughness tester, photoluminescence spectroscopy, and UV/Vis Spectroscopy have been applied to analyze alterations of CR-39 polymeric films to understand the mechanisms of produced alterations by plasma treatment. The obtained FTIR spectra demonstrated that the plasma treatment-related changes in the absorption bands are associated with the treatment time, leading to two critical processes, degradation, and crosslinking. In comparison to the untreated surface, the surface wettability results showed that the liquids' contact angle decreased after treatment with a UF plasma source. This modification in the treated surface denotes an increase in polar groups there, which causes the surface to change to a hydrophilic state. The surface roughness of the samples following plasma treatment showed that UF plasma significantly changed the surface morphology of the CR-39 films. After plasma exposure, considerable emission bands were produced, and the photoemission spectra of the treated film showed a fluorescence response. As the exposure time increased, more fluorescence peaks were formed due to the increase in defects. The UV/Vis spectra showed that the modified films' absorption edges were moved toward lower photon energies. This resulted in a smaller optical energy gap, which led to an expansion of the carbon cluster. Additionally, the untreated sample's transmittance dropped from 92% to 47% for the treated film. In contrast to untreated films, a change in optical characteristics was seen in treated films.

A mechanochemical approach to recycle thermosets containing carbonate and thiourethane linkages

Over the past decades, various industries shifted from traditional materials such as glass and metals to thermoset polymers due to their excellent chemical resistance, thermal stability, reduced weight, and affordability. However, at the end of their life cycle, these highly crosslinked polymers end up as environmental pollutants due to their non-recyclability. To tackle this issue, researchers are exploring vitrimer-type polymers with recyclable qualities, supporting a circular economy and sustainable management of thermoset wastes. This study investigates a new promising method of recycling two commonly used thermosets in commercial applications, poly allyl diglycol carbonate (PADC) and poly thiourethane (PTU), via a mechanochemical process known as vitrimerization. The process involves the cryogenic ball milling of the thermoset with a zinc-based catalyst and a hydroxyl-providing agent, followed by compression molding, enabling the thermoset conversion into a vitrimer. Rheological tests revealed the remarkable stress-relaxation capabilities of the vitrimerized networks, indicating the conversion of the initial permanent crosslinked structures into dynamic networks through vitrimerization. Dynamic mechanical analysis results show that the vitrimerized samples display a consistent rubbery plateau at high temperature, similar to that of permanently crosslinked networks, suggesting a fix crosslink density during the exchange reaction. Differential scanning calorimetry and thermogravimetric analysis results showed that the thermal properties of the vitrimerized samples closely resemble those of the original samples.

Mass spectrometric study of low energy Cs+ ion-induced sputtered fragmentation of PADC polymer.

In this study, low-energy cesium (Cs+ ) ion-induced sputtered fragmentation of poly allyl diglycol carbonate (PADC) was investigated using mass spectrometry. The collision-induced dissociation mechanism revealed emission of various fragments, including monoatomic (H- , C1 - , O1 - ), diatomic (C2 - ), and multiatomic (C3 - , CO2 - , C2 O2 - , C3 O2 - ) species within the Cs+ ion energy range of 1-5keV. The anion current of these fragments exhibited a linear increase with rising incident Cs+ ion energy, indicating a corresponding rise in fragment abundance. Analysis of normalized yield indicated that at 1keV incident energy, the dominant fragment was monoatomic hydrogen (H- ), followed by diatomic carbon (C2 - ), monoatomic carbon (C1 - ), and monoatomic oxygen (O1 - ). Although C2 - remained dominant up to 5keV, other fragments exhibited varying normalized yields at different ion energy steps. The sputter yield estimation revealed that monoatomic hydrogen (H- ) and diatomic carbon (C2 - ) exhibited the highest yields, increasing exponentially beyond 3keV, while multiatomic fragments like C3 - , CO2 - , C2 O2 - , and C3 O2 - displayed the lowest yields. The sputter dissociation mechanism pointed to dehydrogenation, chain scission, and bond breakage as the primary processes during low-energy Cs+ ion impact. Postsputtering Scanning Electron Mircoscope (SEM) micrographs show craters, pits, and micropores on the PADC surface, indicating significant surface degradation. X-ray Diffraction (XRD) spectra exhibited reduced diffraction intensity, while Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated the absence of molecular bands in the IR spectrum, confirming extensive surface damage due to Cs+ ion-induced sputtering.

Studies of chemical bonds loss and optical modifications of CR-39 caused by gamma rays

The induced impacts of high doses of gamma irradiation on the structural variations of poly-allyl-diglycol carbonate (PADC) polymers (CR-39) were studied in terms of X-ray diffraction (XRD) patterns. CR-39 samples were irradiated separately at different ranging from 200 to 800 kGy; (step 200). A deconvolution process of the XRD spectra of CR-39 samples for all gamma irradiation doses was performed. The results of this deconvolution process for the pristine specimen show three diffraction peaks at about 20.30°, 28.16° and 41.70° of 2θ. The broad peaks at 28.16o and 41.70°, and the highest peak at 20.30° of XRD confirm the amorphous nature and low degrees of crystallinity, respectively. The position, area, intensity and full width at half maximum of these peaks are changed with further doses of gamma irradiation. With additional gamma irradiations, the intensities of all peaks decrease significantly. The highest and sharpest peak properties are employed to determine the crystallinity, crystallite size, and radiation chemical yield (G-value) for the loss of carbonate ester bonds using a proposed method. Higher doses of gamma irradiation result in a decrease in crystallinity while increasing crystallite size. Furthermore, the optical band gaps reduced from 4.81 to 3.49 eV when the irradiated dose increased from 0 to 800 kGy. Furthermore, the third order nonlinear susceptibility increased from 0.84x10−12 esu to 2.25x10−12 esu with increasing the radiation doses from 0 to 800 kGy. Moreover, the nonlinear refractive increased from 1.52x10−11 to 3.69x10−11 with increasing the radiation doses from 0 to 800 kGy. On the other hand, the number of carbon atoms in each cluster increased from 51 to 97 when the irradiated dose increased from 0 kGy to 800 kGy.

Impact of high LET radiation on various properties of CR-39 detector

Since polyallyl diglycol carbonate (PADC), viz. CR-39 has been widely used for radiation detection and measurement in various complex radiation fields, therefore, a systematic study has been carried out in this work to demonstrate the significant effect of linear energy transfer (LET) of heavy ions on the optical, structural and chemical (etching) properties of the detector. The PADC samples were exposed to heavy ions (7Li, 12C, 16O and 19F) of different energies to study the effect of LET from 76 to 1002 keV/μm. Samples were chemically processed to develop the latent tracks induced by heavy ions. Image analysis showed an increase in the damaged track size with the LET as well as the etching time. Having same energy, the track sizes of two different ions were found to be different because of the differences in their LET values. Similarly, for one particular ion, the track sizes were found to be smaller for higher energy due to low LET than that of the lower energy corresponding to high LET. Hence, this criterion is successfully demonstrated for particle identification by using PADC. Furthermore, spectrophotometric studies (UV–vis, FTIR) have been carried out to determine the changes in opacity, Urbach's energy, optical bandgap, molecular vibrations and red shift of the cut off wavelength with the increase in LET values.

Assessment of the impact on a PADC neutron dosimetry system of the new operational dose quantities proposed in ICRU report 95.

The International Commission on Radiation Units and Measurements, ICRU, have recommended, in ICRU Report 95, the adoption of new operational quantities for use in radiation protection monitoring. Their implementation will pose problems for instrument manufacturers supplying area dosemeters and for individual monitoring services providing personal dosemeters for radiation workers. The problems arise for photon, neutron and beta dosimetry, but this paper deals solely with neutron personal dosemeters based on poly-allyl diglycol carbonate (PADC) plastic. It presents information on the problems to be expected based on data from calibrations of actual personal neutron dosemeters in terms of the existing dose quantities.

Revealing the mechanism of damage to the carbonate ester in PADC polymeric nuclear track detector using low-energy electron stimulated desorption.

We investigate the mechanism of damage to the carbonate ester chemical functions in Poly allyl diglycol carbonate (PADC) induced by low-energy electrons (LEEs) of <50 eV, which are major components of the initial secondary products of ionizing radiation. PADC is the world's most widely used polymeric nuclear track detector (PNTD) for swift ion detection. Using diethylene glycol monoethyl ether acetate as a surrogate for PADC, we have measured for irradiation with low-energy electrons (LEEs) of <50 eV, the electron stimulated desorption (ESD) signal of O- from 3-monolayer thick films of DGMEA by time-of-flight mass spectrometry. We find that for electron irradiation at energies >6-9 eV, the instantaneous ESD yield of O- increases with the cumulative number of incident electrons (i.e., fluence), indicating that the additional O- signal derives from an electron-induced DGMEA product. From comparison with ESD measurements from films of acetic acid and acetaldehyde, we identify that the additional desorbed O- signal derives from oxygen atoms originally adjacent to the carbonyl bond in DGMEA. Since LEEs are the predominant secondary particles produced by ionizing radiation, this finding helps to better understand the mechanism of damage to carbonate ester in PADC, which is a key step for latent track formation in PADC.

Neutron personal dosimetry using polyallyl diglycol carbonate (PADC): Current status, best practices and proposed research

The objective of this paper is to provide an overview of the current status in neutron personal dosimetry based on poly allyl diglycol carbonate (PADC), also commonly known by the commercial name CR-39, to summarize the best practices in the field, and to point future research directions. An overview of the fundamentals of the technique is given, including a discussion on the PADC material, main parameters and characteristics, practical considerations, dosimetry approaches, and relevant standards. This work also summarizes the best practices adopted by individual monitoring services (IMSs) and discusses the research needed to improve the performance of this type of neutron dosimetry technique, as well as the challenges that make progress difficult. This work is based on the knowledge and experience of several laboratories and investigators and is part of the activities of the European Radiation Dosimetry Group (EURADOS) Working Group 2 –Harmonization of Individual Monitoring in Europe (WG2).

Spectroscopic analysis of fragment products from gamma irradiated poly allyl diglycol carbonate

The investigation of fragment products, structural and optical characterizations of gamma-irradiated Poly Allyl Diglycol Carbonate (PADC) has been analyzed. Gas Chromatography–Mass Spectrometry (GC–MS), X-ray diffraction (XRD) diffractometer, Fourier Transform Infrared (FTIR) Spectroscopy and UV/Vis Spectroscopy have been applied to analyze alterations of PADC polymeric solid state track detector for the understanding the mechanisms of produced alterations by gamma-irradiation. The obtained results show that the irradiated PADC samples contain induced fragment products by gamma radiation. The GC-MS analysis shows that the pristine sample has one compound product with a clear peak of ethylene glycol (EG), but for irradiated samples two compound fragmentation products appeared ethylene glycol (EG) and diethylene glycol (DEG) with different areas %. This is theoretically confirmed, by density functional theory (DFT) using Spartan’20 parallel suite for PADC in neutral and ionized states. The XRD results reveal that the molecules ordering/disordering of irradiated samples have been influenced by gamma exposure according to the values of exposure doses. This increase in disordering is due to the degradation of the polymer chains. An induced change in the band intensities have been observed in FTIR spectra, which indicate to the cleavage in the C–H bond after irradiation. The optical properties studies illustrate that significant modification in the band gap energies after irradiation.

Radiation Damage in the Structure of the CR-39 Nuclear Detector Material as A Result of the Alpha's Energy Loss

In this work, the damage caused by the passage of alpha particles inside the CR-39 nuclear detector material on its chemical structure was studied. All samples at room temperature using a 241Am-Be neutron source with a flux of 5^10 neutrons.cm-2.s-1 were neutron-irradiated. In the CR-39 nuclear track detectors, chemical etching is a critical step in expanding latent tracks. At 70 °C, a NaOH in 6.25N etchant was found to be useful in expanding alpha traces in the CR-39 detector. The track depths of the Alpha particle as a function of etching time for the various energies were increased as etching time increases. The current study uses the nuclear track detector technique to estimate the range of alpha particles. Track etch rates are frequently determined using 2-dimensional photographs of track openings (diameter) or etching time data. The chemical structure along latent tracks and the track formation process were investigated in PADC(poly allyl diglycol carbonate). The findings showed that the measurement of bulk etch rate values by the weight method was 1.42 ± 0.02 μm/h. In addition, the results for the alpha particle range from 4.47 ± 0.05 and 5.8 ± 0.19 μm for alpha energy1.2 MeV and1.47MeV,respectively

Personal Neutron Dosimetry Using Polyallyl Diglycol Carbonate (Padc): Current Status, Best Practices and Proposed Research

Personal Neutron Dosimetry Using Polyallyl Diglycol Carbonate (Padc): Current Status, Best Practices and Proposed Research

Response of nuclear track detector CR-39 to low energy muons

The effectiveness of the PolyAllyl Diglycol Carbonate (PADC) etched solid state nuclear track detector (SSNTD), commonly known as CR-39, as a muon detector is assessed. CR-39 is successfully used to detect higher rest mass particles such as neutrons and protons, and is, for example, widely used in neutron dosimetry applications. CR-39 is generally accepted as being less suitable to detect lower rest mass particles such as muons, and especially electrons, due mostly to their reduced momenta and consequently, reduced stopping power. However, there has been some evidence that CR-39 may have application in the detection of cosmic ray muons. Monte Carlo simulations indicate that CR-39 can detect muons with energies up to 2.8 MeV. Experimental data to demonstrate the ability of CR-39 to detect muons was acquired using the MuSR spectrometer station at the ISIS Neutron and Muon Source. Pits deposited in CR-39 generated by positive muons from the beamline have been characterised and compared with pits deposited by protons and neutrons from other sources. The extent to which a CR-39 SSNTD can discriminate muons from particles with different momenta and rest masses is discussed.

Methodological and Conceptual Progresses in Studies on the Latent Tracks in PADC.

Modified structure along latent tracks and track formation process have been investigated in poly (allyl diglycol carbonate), PADC, which is well recognized as a sensitive etched track detector. This knowledge is essential to develop novel detectors with improved track registration property. The track structures of protons and heavy ions (He, C, Ne, Ar, Fe, Kr and Xe) have been examined by means of FT-IR spectrometry, covering the stopping power region between 1.2 to 12,000 eV/nm. Through a set of experiments on low-LET radiations—such as gamma ray-, multi-step damage process by electron hits was confirmed in the radiation-sensitive parts of the PADC repeat-unit. From this result, we unveiled for the first-time the layered structure in tracks, in relation with the number of secondary electrons. We also proved that the etch pit was formed when at least two repeat-units were destroyed along the track radial direction. To evaluate the number of secondary electrons around the tracks, a series of numerical simulations were performed with Geant4-DNA. Therefore, we are proposing new physical criterions to describe the detection thresholds. Furthermore, we propose a present issue of the definition of detection threshold for semi-relativistic C ions. Additionally, as a possible chemical criterion, formation density of hydroxyl group is suggested to express the response of PADC.

Loss of chemical bonds induced by high doses of γ-radiation in a PADC polymer film: The influence of dose and dose rate on radiation chemical yields

The effects of gamma rays on molecular properties of a poly allyl diglycol carbonate (PADC) polymer, commercially named as CR-39, have been studied. PADC films were exposed to gamma rays at doses ranging from 0.5 to 3 MGy. Gamma exposure induces considerable molecular modifications in PADC films. These modifications were analyzed using Fourier transform infrared (FT-IR) spectroscopy. FT-IR absorption spectra of the gamma irradiated samples show a change in the intensity and the shape of the absorption bands of the chemical groups forming the PADC polymer relative to the pristine one. We have determined G-values for the loss of carbonate ester and ether chemical moieties within PADC. By comparing our G-values with those from other studies, we show that dose rate and dose significantly affect the radiation chemical yields and play an important role of molecular bond kinematics.

Argon ion implanted CR-39 polymer: Optical and structural characterization

The samples of Polyallyl diglycol Carbonate (CR-39) were implanted with 100 keV argon ions at fluences 1 × 1015, 5 × 1015 and 1 × 1016 ions/cm2 to be employed for optical and structural studies. The changes in transmittance, reflectance, optical energy gap and refractive index have been studied through the UV–Vis–NIR spectroscopic technique. The enhancement in reflectivity and a strong reduction in transmittance, particularly in the UV region, are observed after Ar+ implantation in CR-39 samples. The absorbance value remains low ~0.10, 0.15 and 0.20 in the key communication wavelength region i.e. 800–1600 nm for sample implanted at the fluence of 1 × 1015, 5 × 1015, 1 × 1016 Ar+/cm2, respectively. The Optical energy gap (EOPT) is determined to be 0.92 eV for the implanted layer of the sample implanted at the fluence of 1 × 1016 Ar+/cm2, whereas 3.70 eV for the pristine sample. The surface electrical conductivity is increased from ~1.49 × 10−14 S (pristine sample) to ~8.34 × 10−10 S for sample implanted at the fluence of 1 × 1016 Ar+/cm2. The formation of conjugated π-bond (-CC-) structure with Ar+ implantation is confirmed via FTIR and Raman measurements. TGA results are analysed in detail and are found to be in strong agreement with the changes observed in different properties of CR-39 after ion implantation.

Principal Component Analysis applied to neutron dosimetry based on PADC detectors and FNTDs

Solid State Nuclear Track Detectors (SSNTD) have been used as passive dosimeters for many decades. Fast neutron detection is performed by detecting recoil protons generated in a hydrogenous material (neutron converter). The dose is estimated by multiplying the recoil protons track-spots density present on the detector surface by a calibration coefficient obtained from reference irradiations. Therefore, one needs to automatically and reliably discriminate between the track-spots induced by recoil-protons and the spurious signal engendered either by material imperfections or by other ionising particles interactions. The objective of this work is to demonstrate and apply a method, based on the multivariate statistical tool named Principal Component Analysis (PCA), aiming at identifying and filtering out the spurious signal in track detectors. The advantage of this approach is that it can be applied to any type of SSNTD, provided apt definition of initial physical variables describing each track-spot. To show that, we applied the method to poly-allyl diglycol carbonate (PADC) detectors, to filter the signal generated by material imperfections, and to fluorescence nuclear track detectors (FNTDs), to remove the signal induced by other radiation field components. After filtering, dose assessments were compared with reference values of exposures, showing satisfactory agreement. In case of the FNTDs, the procedure proved to be effective regardless of the crystal colouration, which is known to affect signal-rejection techniques based on track-spots fluorescence intensity. The technique also offers the advantage of self-adjusting the filtering parameters based on the currently analysed detector set, as long as calibration and unirradiated detectors are included in the dataset.