Ivans Bočkovs

Characterization of Nanoclay Modified Polycarbonate Blend with Secondary Acrylonitrile Butadiene Styrene Terpolymer

Acrylonitrile butadiene styrene (ABS) terpolymer is one of the major plastics in IT equipment waste stream. In the current research secondary ABS (s-ABS) is blended with polycarbonate (PC) by forming one of the most popular thermoplastics engineering system. The effect of organically modified montmorillonite clay (OMMT) on the tensile properties and thermal stability of PC+10wt.%s-ABS blend is investigated. Increase in stiffness, strength and thermal stability is observed along with rising OMMT content. Highest increments of the aforementioned properties are observed within the OMMT range of 1-1,5 wt.%.

New Thermoshrinkable Materials of Radiation Modified Polypropylene-Elastomer Composites with Cross-Linking Agents

In this work, electron beam modified heterogeneous composites of isotactic polypropylene (PP) with chlorinated polyethylene (CPE) have been investigated. The PP/CPE blend composites with an excess of elastomer (30/70 wt%) have been modified with trimethylolpropane triacrylate (TMPTA) and bisphenol-A-dimethacrylate (BPDMA) cross-linking agents and have been irradiated with accelerated electrons up to ionizing radiation doses from 25 to 150 kGy. The internal stresses characterizing the thermoshrinkage properties (TMP) thermorelaxation stresses formed in thermal heating and the residual stresses resulting in the process of full setting and cooling of materials have been investigated for radiation cross-linked oriented (extended up to 100%) composite samples. The dependence of cross-linking efficiency and the TMP characteristics of PP/CPE heterogeneous blends have been compared to properties of a low density polyethylene (LDPE), which has been commonly used as thermoshrinkable material (TSM) in polymer industry. It has been proved that the radiation-chemically modified PP multiphase composites with elastomers and the crosslinking promoters are comparable perspective materials for creation thermoshrinkable materials with higher or similar thermoshrinkage properties compared to currently exploited TSM.

Radiation-chemically modified PP/CNT composites

Abstract In this work, the authors studied the effects of electron beam (EB)-induced changes in stress-strain characteristics, heat shrinkage stresses, and structure characteristics on polypropylene (PP) composites containing bisphenol-A-dimethacrylate (BPDMA) as the radiation sensitizer and different contents of multi-walled carbon nanotube (CNT) filler (0–2 wt.%). The effect of stearic acid (SA) as the surface modifier on the improvement of CNT dispersion in the PP matrix was also studied. Initially, PP blends with different contents (up to 10 wt.%) of BPDMA were prepared to determine the effective concentration of the sensitizer for the modification of the PP matrix. PP/BPDMA composites and blends filled with CNTs were irradiated up to 25–50 kGy of radiation doses. The properties of unirradiated compositions and those modified by EB, were compared. Radiation-induced changes were confirmed by gel fraction and by the changes in Fourier transform infrared spectroscopy spectra. The results showed an increase in Young’s modulus, yield strength, and thermal-relaxation stresses for the irradiated PP/CNT compositions grafted with 3 wt.% of BPDMA and compatibilized with SA.

Mechanical and thermomechanical properties of radiation modified poly(ethylene-octene)/Ni-Zn ferrite nanocomposites

Poly(ethylene-1-octene) copolymer (POE) composites filled with nickel-zinc ferrite nanoparticles have been modified by exposure to an electron beam at doses up to 500 kGy. The influence of radiation dose and ferrite content on mechanical properties has been investigated. Thermomechanical properties – thermorelaxation stresses formed in thermal heating and thermo residual stresses resulting in the process of full setting and cooling of materials have been investigated for radiation cross-linked oriented (extended up to 100%) composite samples. Increase of concentration of ferrite particles and increase of radiation dose affects a notable increase of elastic modulus and reduces the deformability in comparison to entire elastomer. Improvement of thermomechanical properties especially at low irradiation doses (100–150 kGy) have been detected for composites with increase of ferrite filler content up to 5 wt. %. It was found that gel content of POE increased up to 85% for pristine POE material with increase of irradiation dose up to 500 kGy due to the formation of cross-linked structure, increase of filler concentration up to 5 wt. % affect reduction in gel fraction due to uniform dispersion in amorphous (ethylene and substituted with hexyl branches) POE phases.