Radiation Crosslinking Research Articles

Synthesis and Properties of Targeted Radioisotope Carriers Based on Poly(Acrylic Acid) Nanogels.

Radiation crosslinking was employed to obtain nanocarriers based on poly(acrylic acid)—PAA—for targeted delivery of radioactive isotopes. These nanocarriers are internally crosslinked hydrophilic macromolecules—nanogels—bearing carboxylic groups to facilitate functionalization. PAA nanogels were conjugated with an engineered bombesin-derivative—oligopeptide combined with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate chelating moiety, aimed to provide selective radioligand transport. 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) toluene-4-sulfonate was used as the coupling agent. After tests on a model amine—p-toluidine—both commercial and home-synthesized DOTA-bombesin were successfully coupled to the nanogels and the obtained products were characterized. The radiolabeling efficiency of nanocarriers with 177Lu, was chromatographically tested. The results provide a proof of concept for the synthesis of radiation-synthesized nanogel-based radioisotope nanocarriers for theranostic applications.

Effect of novel sucrose based polyfunctional monomer on physico-mechanical and electrical properties of irradiated EPDM

In this work a novel sucrose based polyfunctional monomer (SPF) was prepared and evaluated as a co-agent in the radiation crosslinking of Ethylene propylene diene methylene linkage rubber (EPDM). The incroporation of SPF boosted the crosslink density which is reflected postively on the gel content and swelling resistance of irradiated EPDM. The mechnical properties of EPDM enhanced as the SPF content increased where the highst tensile strength and elastic modulus were recorded for EPDM which contains 5 phr of SPF. In addition, a decrease in the dielectric constant and an increase in the electrical resistivity of EPDM were observed as SPF content increases. The thermal stability of EPDM was improved after the addition of SPF, especially at temeperature lower than 400 °C.

Effect of split addition of initiator and antioxidant in radiation vulcanised natural rubber latex

In radiation vulcanisation of natural rubber latex (RVNRL), the crosslinking of rubber particles is brought about by γ-radiation from a 60Co source. The optimum radiation dose for obtaining maximum properties for RVNRL film is 15 k.Gy. The residual n-BA in the latex causes several problems in the products derived from the latex. The split dose addition of n-BA was proposed to overcome this difficulty. The order of addition of antioxidants also has some effect on radiation crosslinking reaction as antioxidants are the free radical scavengers. Accordingly, the effect of different modes of addition of antioxidant, on mechanical properties of the vulcanisates, was studied. Among the different methods attempted the addition of antioxidant at mid time (M.I) and after irradiation (A.I) registered better mechanical properties and better thermal stability.

Synergy between vitamin E and D-sorbitol in enhancing oxidation stability of highly crosslinked ultrahigh molecular weight polyethylene

Oxidative stability of radiation crosslinked ultrahigh molecular weight polyethylene (UHMWPE) artificial joints is significantly improved by vitamin E (VE), but there is a dilemma that VE hinders crosslinking and thus jeopardizes the wear of UHMWPE. In this effort, we proposed an efficient strategy to stabilize UHMWPE under limited antioxidant contents, where VE and D-sorbitol (DS) were used as the primary antioxidant and the secondary antioxidant respectively. For non-irradiated blends with fixed antioxidant contents, oxidative stability accessed by oxidation induction time (OIT) of VE/DS/UHMWPE blends was superior to that of VE/UHMWPE blends, while DS/UHMWPE blends showed no increase in OIT. The cooperation between DS and VE exhibited a synergistic effect on enhancing the oxidative stability of UHMWPE. Interestingly, the irradiated VE/DS/UHMWPE blends showed comparable OIT but a significantly higher crosslink density than the irradiated VE/UHMWPE blends. The crystallinity, melting point, and in vitro biocompatibility of the blends were not affected by VE and DS. The quantitative relationships of mechanical properties, oxidation stability, crystallinity and crosslink density were established to unveil the correlation of these key factors. The overall properties of VE/UHMWPE and VE/DS/UHMWPE blends were compared to elucidate the superiority of the antioxidant compounding strategy. These findings provide a paradigm to break the trade-off between oxidative stability, crosslink density and mechanical properties, which is constructive to develop UHMWPE bearings with upgraded performance for total joint replacements. Statement of significanceVE-stabilized UHMWPE is the most commonly used material in total joint replacements at present. However, oxidation and wear resistance of VE/UHMWPE implants cannot be unified since VE reduces the efficiency of radiation crosslinking. It limits the use of VE. Herein, we proposed a compounding stabilization by the synergy between VE and DS. The antioxidation capability of VE was revived by DS, thus enhancing the oxidation stability of unirradiated UHMWPE. The irradiated VE/DS/UHMWPE exhibited similar oxidation stability but higher crosslink density than irradiated VE/UHMWPE, which is beneficial to combat wear of UHMWPE and to inhibit the occurrence of osteolysis. This synergistic antioxidation strategy endows the UHMWPE joint material with good overall performance, which is of clinical significance.

Shape memory function of trans-1,4-polyisoprene prepared by radiation crosslinking with a supercritical CO2 foaming

As a class of smart material, shape memory materials have a great attention due to its potential applications in sensors, textiles, aerospace engineering and medical devices. Herein, we prepared a trans-1,4-polyisoprene (TPI) foam with shape memory properties by radiation crosslinking with the supercritical CO2 foaming method. Firstly, TPI micro-crosslinks were prepared by radiation crosslinking, and then supercritical foaming were carried out. The effect of doses (30 kGy–150 kGy) on TPI foams was investigated. The shape memory behavior of the TPI composite material depends on the crystallinity of the material. The radiation crosslinking method is more suitable to improve the shape memory properties of TPI foam materials. The increase in the dose increases the degree of crosslinking of the material, however it will not crystallize the material significantly. The pores of the microcellular foam material always have a closed-cell structure with the increased dose. While the shape of the cell changes from a honeycomb structure to a circular structure, the cell density increases continuously along with the decreased cell size, and the cell wall changes significantly. As the cell wall thickness increases, the density also increases; the recovery rate of the material increases. The material can achieve a recovery rate of 85% or even ~100% in only 6 s at 100 kGy dose. TPI foamed materials with a high dose can undergo shape recovery at relatively low temperatures. Dielectric study reveals that the introduction of cells can greatly reduce the dielectric constant and dielectric loss of the materials, which improve the insulation performance of TPI. The prepared TPI shape memory materials can be applied in the field of item packaging with good protection and recyclability.

Preparation and characterisation of PCL shape-memory films via photo-crosslinking

ABSTRACT A facile and ecologically friendly method to prepare shape-memory Poly(ϵ-caprolactone) (PCL) films via Ultraviolet (UV) irradiation is described in this work. Benzophenone (BP), as a photoinitiator, was melt-blended with PCL particles directly and then melt-pressed into films. Afterward, a series of shape-memory films were obtained by UV (at around λ=365 nm) irradiation crosslinking. A sequence study and comparison on the properties changes caused by the effect of irradiation temperature was carried out and it turns out that the gel fraction, shape-memory properties and tensile properties of the PCL films, which were photo-crosslinked at 55°C, were significantly higher than that at 25°C. The effect of photoinitiator contents and irradiation time on gel fraction, shape memory properties and tensile properties was also studied. It is considered that UV irradiation is an efficient method to prepare PCL shape-memory films.

Biodegradable cross‐linked poly(1,3‐trimethylene carbonate) networks formed by gamma irradiation under vacuum

AbstractRubbery biodegradable cross‐linked poly (1,3‐trimethylene carbonate) (PTMC) networks were prepared by gamma irradiation under vacuum in the presence of trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), and pentaerythritol tetraacrylate (PET4A). The effect of crosslinking agent, crosslinking agent content (1, 3, 5, 7 wt%), and irradiation dose (25, 50, 75, 100, 125 kGy) on PTMC networks were evaluated. The crosslinking efficiency of PETA was better than that of TMPTA and PET4A at a standard sterilization dose of 25 kGy. The PTMC network with gel fractions up to 92% ± 1% and tensile strength up to 26.0 ± 2.2 MPa could be obtained by adding 7 wt% PETA. The increase in irradiation dose reduced the gel content and network density, and led to a decrease in mechanical properties. The PTMC network extracted by ethanol showed better flexibility and mechanical properties. The irradiation crosslinking of PTMC with 7 wt% PETA followed the Chen–Liu–Tang equation instead of the Charlesby–Pinner equation. The incorporation of crosslinking agents improved the creep resistance and thermal stability, resulting in low permanent set values (5.5%). Furthermore, the enzymatic erosion rates of the networks decreased. Therefore, these PTMC networks can be utilized in a broad range of soft tissue engineering.

Effect of electron beam irradiation on the thermal, mechanical and aging behaviors of polyethylene/carbon black nanocomposite

In this paper effect of electron beam irradiation on the thermal, mechanical and aging behaviors of polyethylene containing nanosized carbon black (PE/CB) was investigated to find its potential applicability as an absorber material for solar thermal collectors. SEM images obtained before irradiation of PE/CB nanocomposite containing 2.25 wt% CB, proved a good dispersion of CB in polymer matrix. PE/CB samples were irradiated by electron beam at doses ranging from 100 to 200 kGy. The results obtained from both the gel–sol and the hot set analyses show that the degree of crosslinking, subsequently thermal stability, is dose-dependent. The best mechanical properties were observed for PE/CB sample crosslinked at 100 kGy. From the Differential Scanning Calorimetry (DSC) analysis it was found that thermal aging of 100 kGy irradiated sample in hot air at 140 °C for 100, 200 and 400 h causes a prominent increase in melting point and degree of crystallinity during initial 100 h, followed by a slower increase at longer aging times. In addition, decreasing the oxidation temperature (Tox) values show that during thermal aging chemical changes occur in the irradiated sample. A slightly increase in carbonyl index (CI) displays fairly degradation after 400 h aging time. The solar thermal absorbance is nearly independent of radiation crosslinking of PE/CB.

Efficient sensitizer-supported electron beam irradiation induced crosslinking of polyvinylidene fluoride for shape memory applications

Polyvinylidene fluoride (PVDF) preferentially crosslinks upon exposure to ionizing electron beam irradiation, leading to substantial changes in its physicomechanical and thermophysical properties. However, low dose electron beam irradiation produces inefficient crosslinking in pure PVDF while high dose irradiation tends to induce the concomitant process of transverse bond degradation. This has been addressed by incorporating a sensitizer into PVDF to increase crosslinking efficiency under low dose irradiation. However, conventional sensitizers typically suffer from self-polymerization and the release of toxic volatile gases at high temperature, which diminishes the crosslinking efficiency and is toxic. This issue is addressed here via a series of well-designed bismaleimide (BMI) sensitizers and incorporating these into PVDF films for facilitating chemical crosslinking reactions under low electron beam irradiation doses. Analysis indicates that the sensitizing action of the proposed BMI sensitizers may be due to the formation of transverse bonds between vinylene groups and PVDF chains. Versus conventional triallyl isocyanurate and trimethylolpropane triacrylate sensitizers, the proposed BMI sensitizers facilitate high radiation crosslinking efficiency and exhibit good compatibility. Accordingly, the proposed sensitizers leading to irradiated PVDF films with outstanding thermomechanical performance and shape memory functionality.

Human organ phantoms for catheterization using the radiation crosslinking technique

AbstractAn artificial organ based on polyvinyl alcohol (PVA) hydrogel was developed to train medical staff to improve their ablation therapy skills, by using the radiation cross‐linking technique. The aqueous PVA solution was irradiated with γ‐rays or electron beams to produce a highly transparent, high‐strength, and flexible crosslinked hydrogel without using a crosslinking agent. Physical properties of the hydrogel, such as, gel fraction, swelling, and elastic modulus, were controlled by changing the radiation dose. The catheter ablation region on the surface of the cardiac phantom produced from PVA hydrogel with temperature‐responsive pigment inks can be visually identified by the color change. The tumor organ phantom consists of the PVA hydrogel with the purple pigment ink (healthy organ site) and red PVA hydrogel with cellulose (the tumor sites) was developed by applying this radiation crosslinking technique. The positions of the tumor hydrogel and the ablation electrode needle can be confirmed through ultrasound echography. It is possible to practice ablation on the tumor site while observing the echo images under conditions similar to the actual treatment. These novel human organ phantoms are created as a means for ablation training for treating cardiac arrhythmia and liver cancer using the radiation crosslinking technology.

Diffusion behavior of vitamin-E in irradiation cross-linked GO/UHMWPE composites

Graphene oxide/ultra-high molecular weight polyethylene (GO/UHMWPE) composite was prepared by hot pressing and irradiation cross-linked by γ-ray. Vitamin-E (VE) solution was diffused into matrix and homogenize treated to study the diffusion behavior. Weight change, diffusion depth and VE index after VE diffusion were studied. The results show that after VE soaking, the weight change is, however, not obvious at low temperature (80 °C and 100 °C), while apparent at 120 °C. Furthermore, the weight change of UHMWPE is most, while least of irradiation cross-linked GO/UHMWPE. GO filling and irradiation cross-linking had no significant effect on the molecular structure of UHMWPE, the characteristic peaks of VE can be clearly seen in the FT-IR. The diffusion depth of VE in UHMWPE is the largest, which is 280 μm. On the contrary, the shallowest diffusion depth of 70 μm in composites modified by GO and irradiation. The cross-linking degree caused by irradiation and larger two-dimensional structure of GO hindering VE diffusion, more soaking time and temperature are required to provide greater activation energy to obtain desired thickness. Besides, diffusion equation also established as a function of time and temperature based on Fickian theory, which is conducive to predict the diffusion depth of VE into UHMWPE matrix composite for targeted modification. Furthermore, diffusion mechanisms of VE also illustrated.

Controlled bacteriostasis of tea polyphenol loaded ultrahigh molecular weight polyethylene with high crosslink density and oxidation resistance for total joint replacement

To avoid catastrophic bacterial infection in prosthesis failure, ultrahigh molecular weight polyethylene (UHMWPE), a common bearing material of artificial joints, has been formulated with antibiotics to eliminate bacteria locally at the implant site. However, the pressing issues regarding cytotoxic effects and evolution of drug resistant bacteria necessitates the development of bio-friendly bacteriostat with long bacteriostatic efficacy. Herein, tea polyphenol extracted from nature source was introduced in UHMWPE as a biogenic antimicrobial. Controlled antimicrobial activity was achieved by chemical crosslinking to regulate the release of the tea polyphenol. In addition, the crosslinking efficiency of UHMWPE blends with high loaded tea polyphenol was significantly improved in comparison to radiation crosslinking. The immobilized tea polyphenols also enhanced the oxidation stability of the UHMWPE, which is essential to prolong the service life in vivo and the storage time in vitro. The blends presented good biocompatibility, despite cell repellent on the highly crosslinked surface. Chemically crosslinked tea polyphenol/UHMWPE exhibited feasible properties for total joint implants, which is promising for clinical application.

Gamma radiation synthesis of a novel amphiphilic terpolymer hydrogel pH-responsive based chitosan for colon cancer drug delivery

Particularly, chitosan (Cs) loaded with drug cannot pass through the colonic region, often leading in the bursting drug release in the stomach due to its solubility in gastric contents. The novelty of the current article is to solve this limitation by performing gamma irradiation cross-linking of Cs with two anionic polymers of (acrylic acid)-co-(2-acrylamido-2-methylpropane-sulfonic acid) (AAc/AMPS) to give amphiphilic hydrogel. The shifted in the characteristic FTIR peaks of Cs in the (Cs/AAc/AMPS) confirm the exits of inter-molecular interactions that make Cs and (AAc/AMPS) are miscible. Swelling experiments under different pH indicated that the (Cs/AAc/AMPS) hydrogels were significantly sensitive to pH change. The results give the possibility to use the obtained (Cs/AAc/AMPS) hydrogel on drug delivery system. The in vitro Fluorouracil (5-FU) releasing from (Cs/AAc/AMPS) matrix was examined under the influence of pH1 and pH7.The results confirmed the hydrogels capability to release 96 % of 5-FU drug at pH 7 after 7 h.

A Gel Polymer Electrolyte Reinforced Membrane for Lithium-Ion Batteries via the Simultaneous-Irradiation of the Electron Beam.

In this research, a series of innovative and stable cross-linked gel polymer reinforced membranes (GPRMs), were successfully prepared and investigated for application in lithium-ion batteries. Herein, a gel directly within the commercial polyethylene (PE) separator is supported via electron-beam simultaneous irradiation cross-linking of commercial liquid electrolyte and poly(ethylene glycol) methacrylate (PEGMA) oligomers. The physical and electrochemical properties of the GPRMs were characterized by SEM, TEM, mechanical durability, heating shrinkage, and ion conductivity, etc. The GPRMs demonstrated excellent mechanical durability and high ion conductivity compared with traditional PE membranes. Moreover, coin-typed cells were assembled and cycle performance was also studied compared with same-typed cells with commercial PE membrane and liquid electrolyte. As a result, the coin-typed cells using GPRMs also showed a relatively good efficiency on the 50th cycles at a high 1.0 C-rate. These GPRMs with excellent properties present a very promising material for utilization in high-performance lithium-ion batteries with improved safety and reliability.

Radiation Crosslinked Smart Peptide Nanoparticles: A New Platform for Tumor Imaging.

Nanoparticles have been employed to develop nanosensors and drug carriers that accumulate in tumors. Thus, it is necessary to control the particle size, surface potential, and biodegradability of these nanoparticles for effective tumor accumulation and safe medical application. In this study, to form a nanoparticle platform suitable for diagnostic and drug delivery system (DDS) applications, peptides composed of aromatic amino acid residues were designed and synthesized based on the radiation crosslinking mechanism of proteins. The peptide nanoparticles, which were produced by γ-ray irradiation, displayed a positive surface potential, maintained biodegradability, and were stable in water and phosphoric buffer solution during actual diagnosis. The surface potential of the peptide nanoparticles could be changed to negative by using a fluorescent labeling reagent, so that the fluorescent-labeled peptide nanoparticles were uptaken by HeLa cells. The radiation-crosslinked nanoparticles can be applied as a platform for tumor-targeting diagnostics and DDS therapy.

Application of tragacanth gum and alginate in hydrogel wound dressing's formation using gamma radiation

Herein this work, hydrogel wound dressings were formed from polysaccharide tragacanth and alginate gum by radiation induced copolymerization technique. The synthesis, characterizations (cryo-SEM, AFM, FTIR, 13C-NMR, XRD, TGA-DSC) and biomedical tests (wound fluid uptake, haemocompatibility, oxygen permeation, water vapor permeation, mucoadhesion, microbial penetration, mechanical properties and protein adsorption) of the hydrogels were major points of discussion along with the evaluation of drug delivery. Hydrogels absorbed simulated wound fluid of 4.45 ± 0.11 (gram/gram of gel) and were found permeable to O2 and H2O vapour and impermeable to microorganisms. The release profile of antibiotic and anesthetic drugs, (amikacin and lidocaine) obeyed Fickian diffusion. Overall, radiation crosslinking could produce sterile medicated hydrogel dressings with improved mechanical properties to manage the microbial infection and pain of the wounds simultaneously.

Influence of Solid TAIC on Crosslinking LLDPE by Electron Beam Radiation

Abstract In this work, solid triallyl isocyanurate (TAIC) has been fabricated and used as the crosslinking sensitizer for linear low density polyethylene (LLDPE) crosslinking application. First, 0 phr, 1.5 phr, 3.0 phr, 4.5 phr and 6.0 phr solid TAIC have been added into the LLDPE to study the radiation crosslinking results. The resulting samples are measured by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), etc. The results reveal that the crystallinity, melt point, elongation and volume resistivity decrease when the content of solid TAIC increases in LLDPE from 0 phr to 6.0 phr. However, adding a proper amount of solid TAIC (3.0 phr) can improve the crosslinking degree and tensile strength of LLDPE. Finally, the space charge distribution of the samples has been measured, and the possible mechanism of solid TAIC that affects the LLDPE electrical properties is proposed.

Ultra-small size gelatin nanogel as a blood brain barrier impermeable contrast agent for magnetic resonance imaging

Magnetic Resonance Imaging (MRI) contrast agents with rapid renal excretion that do not penetrate the blood brain barrier (BBB) and blood cerebrospinal fluid barrier (BCFB) are preferred for safer and low-risk diagnosis. Gadolinium (Gd)-conjugated nanoparticles have been proposed for use as contrast agents; however, the particle size must range between 1 to 7 nm to ensure rapid renal excretion. In this study, three types of gelatin, dissolved in water at varying concentrations of 0.1–2 wt.%, were irradiated with 5 kGy γ-rays at 25°C under aerated conditions to produce ultra-small gelatin nanogels having an average particle size ranging between 6 ± 2 to 21 ± 4 nm. Ultra-small Gd-coordinated gelatin nanogels (GdGN) suitable for use as MRI contrast agents were produced using 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid mono-N-hydroxysuccinimide ester (DOTA-NHS) and DOTA-butylamine as Gd ligand derivatives. Non-cytotoxicity and effective relaxivity of GdGN as a positive MRI contrast agent were verified using in vivo experiments. Rapid renal excretion of GdGN was observed in mice within 1 h with no accumulation in the liver. GdGN did not migrate across the BCFB in normal mice, thus emphasizing its safety as an MRI contrast agent. Statement of significanceThe authors developed ultra-small sized gelatin nanogels as blood-brain-barrier impermeable contrast agents for magnetic resonance imaging (MRI). The authors used radiation crosslinking technique to ensure better integrity of the amino acids present in the gelatin nanogels while conjugating with gadolinium (Gd) to form gadolinium-coordinated gelatin nanogels (GdGN). The safety and efficacy of GdGN, as MRI contrast agents, were verified by in vivo studies. GdGN exhibited rapid renal excretion within 90 minutes and no passage across the barriers in the brain.

Radiation crosslinking of linear polyethyleneimine‐based nanoparticles grafted to poly(glycidyl methacrylate) via trimethylolpropane triacrylate as potential electronic packaging material

AbstractLinear polyethyleneimine (L‐PEI)‐based nanoparticles were synthesized via hydrolysis of poly‐2‐methyl‐2‐oxazoline (PMeOx), which was prepared by cationic ring‐opening polymerization of the oxazoline five‐membered ring. Herein, a kinetic study of the ring‐opening polymerization reaction is discussed. The nuclear magnetic resonance spectrum of PMeOx verified the presence of repeating units and terminal groups in the polymer's structure. Molar ratios of PEI and PMeOx were characterized using size exclusion chromatography with low‐polydispersity polymer chains as the controlled polymerization reaction. PEI and PMeOx exhibited narrow particle size distribution with hydrodynamic radii of 89 and 67 nm, respectively, as determined via dynamic light scattering analysis. In addition, atomic forces and scanning electron microscopy were used to investigate the topography of the PEI thin films. Poly(glycidyl methacrylate) P(GMA) was grafted onto a PEI chain in the presence of trimethylolpropane triacrylate (TMPTA) as the crosslinking agent to synthesize the P(GMA–PEI–TMPTA) tripolymer via free radical polymerization using gamma irradiation. The thermal characterization of the P(GMA–PEI–TMPTA) tripolymer was conducted using thermogravimetric analysis and differential scanning calorimeter. Generally, the thermal stability of the P(GMA–PEI–TMPTA) tripolymer was improved at low‐glycidyl methacrylate concentrations. The prepared tripolymer could be used as effective packaging materials for electronics industries.

Influence of the β- Radiation/Cold Atmospheric-Pressure Plasma Surface Modification on the Adhesive Bonding of Polyolefins.

The goal of this research was to examine the effect of two surface modification methods, i.e., radiation cross-linking and plasma treatment, on the adhesive properties and the final quality of adhesive bonds of polypropylene (PP), which was chosen as the representative of the polyolefin group. Polymer cross-linking was induced by beta (accelerated electrons—β−) radiation in the following dosages: 33, 66, and 99 kGy. In order to determine the usability of β− radiation for these applications (improving the adhesive properties and adhesiveness of surface layers), the obtained results were compared with values measured on surfaces treated by cold atmospheric-pressure plasma with outputs 2.4, 4, and 8 W. The effects of both methods were compared by several parameters, namely wetting contact angles, free surface energy, and overall strength of adhesive bonds. Furthermore, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were conducted. According to our findings the following conclusion was reached; both tested surface modification methods significantly altered the properties of the specimen’s surface layer, which led to improved wetting, free surface energy, and bond adhesion. Following the β− radiation, the free surface energy of PP rose by 80%, while the strength of the bond grew in some cases by 290% in comparison with the non-treated surface. These results show that when compared with cold plasma treatment the beta radiation appears to be an effective tool capable of improving the adhesive properties and adhesiveness of PP surface layers.