It was found that radiation-induced processes in films of negative photoresist NFR 016D at doses up to 2 × 1015 cm–2 occur mainly with the participation of residual solvent molecules or on by-products of the photoresist film synthesis. After irradiation, absorption bands with maxima at 1717 (stretching vibrations of C=O bonds), 1068, and 1009 cm–1 (vibrations of C–O–C bond in methyl-3-methoxypropylate solvent) disappear in the attenuated total internal reflection spectra of the photoresist. At irradiation doses above 1 × 1016 cm–2, significant changes in the intensity of the bands associated with the main component of the photoresist (phenol-formaldehyde resin) were observed. A noticeable transformation of the spectrum occurs in the region of 1550–1700 cm–1, in which stretching vibrations of C=O bonds are observed. At irradiation doses above 2 × 1016 cm–2, the intensities of the bands caused by stretching vibrations of CH2 and CH groups decrease (bands with maxima at 2925 and 3012 cm–1, respectively). The experimental results indicate a change in the composition of substituents at the carbon ring and the formation of conjugated double C=O bonds when the photoresistive film is irradiated with electron doses above 2 × 1016 cm–2.

The impact of high-dose e-beam and gamma-irradiation, followed by long-term aging, on the structural properties of poly(L-lactide) (PLA) was investigated. Due to prolonged exposure, gamma-irradiation caused more extensive oxidative degradation, accelerating the aging process compared to e-beam irradiation. Aging effects were most pronounced in samples irradiated at doses exceeding 600 kGy. Structural analysis using H-1 NMR revealed distinct mechanisms of chain scission during irradiation and aging, resulting in the formation of different end groups. Irradiation-induced deterioration of PLA's phase structure occurred during irradiation was observed, including the formation of conformationally disordered alpha ' crystalline form. Aging at doses exceeding 1000 kGy led to amorphization. The degradation behavior of aged PLA in water and its recycling potential were also evaluated. While partial dissolution of aged samples occurred in a short-term, further degradation was hindered by water-induced crystallization. Unirradiated and low-dose irradiated PLA demonstrated promising recyclability to lactide, highlighting its potential for industrial-scale chemical recycling as a sustainable alternative to landfilling or composting.

Синтезированы гибридные гидрогели посредством прививки акриламида к макромолекулам картофельного крахмала по радикальному механизму в водно-полимерных системах. В качестве инициатора полимеризации использовали персульфат аммония, а в качестве сшивающего агента ‒ N,N′-метилен-бис-акриламид. Структура и свойства привитого сополимера крахмала с акриламидом изучена методами фурье-ИК-спектроскопии, рентгенофазового анализа и термогравиметрии. Высказано предположение, что центрами прививки полиакриламида к макромолекулам крахмала являются преимущественно первичные атомы углерода полисахарида. Изучено влияние массовых соотношений реагентов на сорбционные и реологические свойства полученных гидрогелей. Проведено химическое модифицирование гидрогелей на основе привитых сополимеров крахмала с акриламидом посредством щелочного гидролиза. Установлено влияние гидролиза на сорбционную способность гидрогелей по отношению к ионам тяжелых металлов (на примере ионов Cu(II)).

The phase state of Cu2+ complexes with acrylamide and sodium acrylate copolymers at different copolymer concentrations and components molar ratios was studied. The change in complex stoichiometry from 2 to 3 carboxylate groups per Cu2+ ion was detected with an increase of copolymer concentration. In the concentrated solutions of copolymers, gelation is observed upon addition of Cu2+ ions, with the lowest concentration of copper required for gelation decreasing with the increase in copolymer concentration. These hydrogels are attributed to the formation of meta-stable inter-polymer metal complexes, which are able to persist due to a low segment mobility. The phase separation of complexes is shown to be associated with the bidentate coordination of carboxylate groups to Cu2+ ions, while the hydrogels formed in concentrated solutions mostly consist of bridging structures. Gelation threshold corresponds to the second critical concentration of poly(acrylamide-co-sodium acrylate) and is lower for copolymers with the higher molecular weight. Low acrylate content in the copolymers prevents collapse of the hydrogels caused by the salting-out effect. A higher gel content can be reached by increasing the copolymer concentration or the molar ratio of copper ions to carboxylate groups, with the latter reducing the swelling degree.

Attenuated total internal reflection (ATR) spectra of polyimide PI-2610 films deposited on single-crystal silicon wafers by centrifugation were studied after irradiation with 5-MeV electrons in a linear accelerator at doses of 1∙1014–2∙1015 cm–2. The strongest bands in the spectrum of the PI-2610 polyimide films were attributed to vibrations of the imide ring C–N–Cst (1349 cm–1) and aromatic ring (1517 cm–1), stretching vibrations of the imide ring C=Ostr (1700 cm–1) and CO–Cst-group C–C bonds (1074 cm-1), and bending vibrations of C–H bonds with maxima at 734 and 828 cm–1. The spectral shape and intensities of bands with maxima at 1700 and 1349 cm–1 due to C=O and C=N–Cstr vibrations were observed to change at an initial dose of 1∙1014 cm–2. It was assumed that this was due to relaxation of metastable states of these groups. The intensities of bands corresponding to asymmetric and symmetric stretching vibrations of C–H2 bonds decreased at a dose of 2∙1015 cm–2. The intensities of ATR bands due to vibrations of C=O and C–N bonds and aromatic and imide rings practically did not change.

Photoresist (PR) NFR 016D4 films deposited on the surface of silicon (Si) wafers by centrifugation were studied by attenuated total internal reflection Fourier-IR spectroscopy. Background absorption of the PR/Si structures was observed to increase at wave numbers <1600 cm −1 because of the effect of electromagnetic radiation on the Si substrate and scattering/reflection at the PR/Si interface. Asymmetry in the force field of the aromatic ring in the NFR 016D4 film was detected. Spectral features of thick PR NFR 016D4 films were due to the presence of residual solvent. Formaldehyde formed by fragmentation of hydroxymethyl residues in the phenol-formaldehyde resin was detected in irradiated films. Radiation-induced processes in PR NFR 016D4 films at doses up to 2∙10 15 cm −2 involved mainly residual solvent molecules or by-products of PR film synthesis.

Data on irradiation of poly(L-lactide) (PLLA) based active packaging is still limited. Therefore, effect of gamma-irradiation on neat PLLA and active packaging with oligohexamethylene guanidine hydrochloride (OHMGHCl) has been studied. Combined use of irradiation and active packaging technology is promising approach to maintain food safety and prolong shelf life. It has been found that regardless of the OHMGHCl content PLLA undergoes chain scission during irradiation and this process becomes less pronounced at doses higher than 50 kGy. Slight racemization of PLLA during exposure has been observed using polarimetry and C-13 NMR spectroscopy. Mechanical properties of films have been examined. Biocide addition led to a 30% decrease in films elongation at break. Irradiation either caused elongation decrease. Dose of 50 kGy and higher made PLLA active films brittle. Multiple melting behavior of irradiated PLLA has been analyzed by differential scanning calorimetry. Fraction of crystals with higher melting temperature rose with dose. Possible reason for this phenomenon is formation of alpha ' form with less ordered chain packaging that recrystallizes during heating. The biocide addition has not affected this process. Furthermore, in vitro antimicrobial test has shown efficacy of films with 2 wt.% of OHMGHCl against gram-negative, gram-positive bacteria and fungi.

Hybrid hydrogels have been synthesized by radiation grafting of acrylamide to chitosan chains. The structure of the acrylamide-grafted chitosan was examined using FTIR spectroscopy, X-ray diffraction and simultaneous thermal analysis. It has been determined that both hydroxyl and amino groups of the polysaccharide are the grafting centers of growing polyacrylamide chains on the chitosan macromolecules. The effect of the reagents ratio on the sorption and rheological properties of the obtained hydrogels has been studied. Hydrogels based on acrylamide-grafted chitosan were modified chemically by alkaline hydrolysis, and the effect of hydrolysis on the sorption capacity of hydrogels with respect to water and Cu(II) ions was examined.

The present study aimed to examine the effect of gamma-irradiation on subsequent hydrolytic degradation of poly(L-lactide) (PLLA) and polymer crystallization behavior during this process. Absorbed doses were 29 and 75 kGy, unirradiated sample was also studied. Hydrolysis was performed at 60 degrees C for up to 50 days. Radiation treatment of PLLA accelerates hydrolysis process. It affects polymer mass loss, molecular weight distribution, change of hydrolysis media pH, and values of the hydrolytic degradation rate constant. Preliminary irradiation makes it possible to eliminate the induction period of PLLA mass loss during hydrolysis. However, a decrease of polymer molecular weight during irradiation leads to an increase of PLLA crystallization rate upon hydrolysis. It was found that alpha crystals can be formed during hydrolytic degradation. Parameters of PLLA unit cell were calculated. When polymer degree of crystallinity becomes high enough its hydrolytic degradation slows down. Thus, faster crystallization of irradiated PLLA reduces the acceleration effect of radiation treatment on polymer hydrolysis.

The DLC/Kapton structures irradiated with 60 Co γ-rays at doses to 1 MGy have been studied by measuring transmission and attenuated total reflection (ATR) spectra. It has been shown that there are significant changes in the spectra in the ranges of vibrations of О–Н, CH 2 , and CH 3 bonds due to radiation-induced processes in the byproducts of polyimide synthesis and residual solvents. Significant differences were found in the radiation-induced processes occurring in the bulk and near-surface region of a polyimide film and DLC/polyimide structures. After irradiation, the bulk of polyimide exhibited bands due to asymmetric and symmetric vibrations of the CH 3 group. Bands associated with the vibrations of the CH 2 group were additionally observed in the near-surface region. The formation of CH 2 groups in the near-surface layer under irradiation was more pronounced in DLC/polyimide structures than in polyimide films; this was due to the additional supply of hydrogen from the DLC film.

Fourier-transform infra-red spectroscopy with frustrated total internal reflection was used to study radiation-induced processes upon the implantation of boron and phosphorus ions into positive FP9120 diazoquinone-novolac photoresist films on silicon. Strengthening of the photoresist adhesion to monocrystalline silicon was found to be caused by the formation of ester linkages between hydroxyl groups on the surface of the silicon wafer oxide layer and carboxyl groups of 1-H-indene-3-carboxylic acid.

Diazoquinone–novolac photoresist FP9120 films of 1.0–2.5 μm in thickness with boron ions, implanted at an incident ion energy of 60 keV and a fluence of 5 × 10 14 –1 × 10 16 cm −2 , have been studied using attenuated total reflection (ATR) FTIR spectroscopy. It has been shown that ion implantation leads to the appearance in the layer beyond the range of ions of intense ATR bands with maxima at 2151 and 2115 cm −1 due to stretching vibrations of C=C=O cumulative double bonds formed as a result of denitrogenation of o ‑naphthoquinone diazide. During implantation, a redistribution of intensities was observed between the maxima of the ATR bands due to the terminal methyl groups and methylene groups in favor of the latter. This may indicate radiation crosslinking of novolac resin molecules, involving radicals with the unpaired electron localized at the terminal methyl groups.

The composition of macromolecular complexes formed at a room temperature by mixing aqueous solutions of acrylamide and sodium acrylate copolymer, which was obtained by alkaline hydrolysis of polyacrylonitrile fiber, with Cu(II), Zn(II), Co(II), and Mn(II) sulfates have been shown to depend upon the molar ratio of the copolymer carboxylate group and the metal ion in the solution. The type of the complexes formed between the metal ions studied with the copolymer carboxylate group has been identified by the Fourier-IR spectroscopy. Сonditions have been found of preferable formation of bidentate and/or monodentate complexes as well as bridging (or pseudo-bridging) bonds. The possibility of nitrogen atoms of the amide group participation in the formation of a coordination bond with Cu(II) ions has been shown. Changing hydration degree of the amide group of the copolymer has been suggested to take place during the formation of bidentate insoluble hydrophobic complexes between metal ion and the copolymer carboxylate group (at molar ratios of COO– – Me(II) of 1 : 1 and 2 : 1).

Introduction of copper(II), zinc(II), and manganese(II) ions into aqueous solutions of acrylamide–sodium acrylate copolymer leads to phase separation. The position of the boundary between the liquid phase and the precipitate is determined by the copolymer composition, its concentration in solution, and nature and concentration of the ion being introduced.

Polyelectrolyte hydrogels based on copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid were prepared by frontal copolymerization in dilute aqueous solutions of the monomers using ammonium persulfate as initiator chromium triacetate as cross-linking agent. The influence of the monomer molar ratio, initiator and cross-linker concentration on the possibility of performing the copolymerization and monomer reactivity ratios in the frontal mode, and on the characteristics of the obtained hydrogels was examined.

Copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid and polyelectrolyte hydrogels based on them were prepared by frontal copolymerization in concentrated aqueous solutions of the monomers using ammonium persulfate as initiator. The influence of the monomer molar ratio and initiator concentration on the possibility of performing the copolymerization in the frontal mode and on the characteristics of the copolymers and hydrogels obtained was examined.