Marina Vukoje

Reduced water permeability of biodegradable PCL nanocomposite coated paperboard packaging

In this work, we studied the properties of printed paperboard samples coated with biodegradable PCL polymer, which was considered to overcome the disadvantages (barrier properties) of a paper-based material. Additionally, the samples were coated with PCL modified with SiO2 and Al2O3 nanoparticles. The characterization of the coated paperboard (with print) samples was made by determination of water vapor transmission rate (WVTR), contact angle of water and its evolution over time, and mechanical and visual properties. The samples were also examined by SEM microscopy. The results show that PCL and PCL coatings modified with SiO2 and Al2O3 nanoparticles slow down the water vapor transmission rate when compared to the paperboard without coatings. The water contact angle measurements show an increase in hydrophobicity in paperboard coated with PCL-SiO2, while PCL-Al2O3 shows a decrease when compared to neat paperboard and paperboard coated with neat PCL. The studied coated samples also improve mechanical properties of paperboard while preserving the visual properties of print.

Thermochromic ink - paper interactions and their role in biodegradation of UV curable prints

In this study, biodegradability aspects of UV thermochromic leuco dye print on three different paper materials (synthetic, recycled, and bulky) were studied using the soil burial test under anaerobic conditions. Biodegradation of UV curable thermochromic prints were evaluated for changes by visual examination, microbial growth assay, weight loss measurements, Fourier transform infrared spectroscopy, scanning electron microscopy and colorimetric measurements. Results showed a better absorption of ink into the bulky paper structure, followed by recycled paper. Synthetic paper is not absorbent. The ink binder altogether with classic pigment and microcapsules penetrates into the structure of bulky paper. Recycled paper absorbs ink binder mostly with classic pigment. Better adsorption of binder into the bulky paper structure results in thinner layer of ink binder on the paper surface. On non-absorbent synthetic paper, microcapsules are covered with thicker layer of ink binder. In the case of bulky paper, the highest rate of biodegradation was observed, resulting in a higher number of bacteria, higher weight loss, higher changes in colour (destruction of almost all microcapsules) and almost complete reduction in thermochromic effect of the prints. Results show that microcapsules, which penetrate into the structure of bulky paper, are promoting the rate of bulky paper biodegradation. The opposite behaviour was noticed for the penetration of classic pigment into the structure of recycled paper, which resulted in remarkable reduction of recycled paper biodegradation rate. The thicker layer of ink binder (containing classic pigment) on the surface of microcapsules on recycled paper resulted in slower rate of microcapsules degradation and smaller colour change of the print. The thickest layer of ink binder and classic pigment on synthetic paper surface causes the slowest rate of biodegradation of print.

Thermochromic offset ink – paper interactions and print biodegradation

The paper presents the results of the research on the manifestation of the chromatic effect crispening, where the primary stimuli are designed as squares in the blue-green color with the values of 55% RTV and 65% RTV, while the secondary stimuli are designed as backgrounds in the purple color and their variations are made in the values of 25% RTV, 50 % RTV, 75% RTV and 100% RTV that surrounds the primary stimuli. Ten respondents of both sexes participated in the research. They had the task to match on a computer screen through the binocular harmonization technique the test primary stimuli with the referential stimuli, so that the test primary stimuli are perceived the same or equal to the referential primary stimuli. The intensity of the effect was determined and presented in the CIEDE00 system. The results of the research show that the intensity of the effect was more pronounced on the test primary stimuli of 65% RTV, where the deviations in the perception of color were more pronounced. The smallest deviation was measured on the primary stimulus of 55% RTV with the background of 75% RTV, which is also a recommendation to the designers when creating a conceptual solution with the combination of pairs presented in this paper.The machine printing and rapid cultural development in Europe begins with the discovery of metal lettering at the end of the 15th century. This printing technique has been named the letterpress printing and is one of the greatest inventions of mankind. The development of printing was one of the main indicators of the development of individual countries. We believe that today in the world and in Europe the Croatian development of that age is significantly neglected. This paper presents European development and development in Croatia. This paper will contribute to a more accurate evaluation of Croatian printing and cultural level of that time by displayingCroatian achievements of that era, the printing staff, printed works and printing houses, throughout European and Croatian development of printing.This paper presents a novel highly directive ultra-wide band antenna for using in microwave imaging systems. Defected Ground Structure (DGS) is incorporated in the top and side of the ground plane to enhance the bandwidth impedance matching. Subsequently, for the further improvement in the bandwidth, gain and directivity staircase slot and square slot is etched at the bottom and top edge of the square patch plane. The low-frequency performance of the proposed antenna can be achieved by adjusting the gap between the ground and patch plane. The proposed microstrip antenna is fabricated on a Flame Retardant (FR4) plate of laminate substrate with dielectric constant of 4.3. The result shows that a directivity of 2.2-8.4dBi is achieved across a bandwidth from 1.43-8.92GHz. Furthermore, gain, directivity, radiation pattern characteristic and reflection coefficient have also been analyzed at the different resonant frequency.The most important role of packaging is protecting a product, but also stimulating purchasing decision. Products on store shelfs can often be found packaged in different materials, even when they are of the same net weight. This study investigated how different packaging materials affect purchasing decision. The aim was to evaluate the user’s tendency towards a particular packaging material in relation to its functionality and environmental protection. Test samples were three common powder products: instant coffee, cocoa and sugar. Respondents’ task was to select one of the following packaging materials: glass, tin and composite material for coffee; rigid and flexible plastics for cocoa and sugar. The results showed that the user’s tendency towards packaging material is influenced by packaging functionality. In addition, technical (protection, recyclability) and ergonomic (presence of the lid, easy to dose and reusability) attributes have found to be essential criteria for the choice of packaging. Furthermore, this study showed that customers are ecologically aware since they tend to re-use the packaging, thus enhancing environmental care.Unique Arabic typography has different applications in local newspapers whether traditional newspapers or online forms. It started as an art and developed as a science which has been utilized to improve the way of communicating ideas. In Egyptian newspapers, typography has been used as a medium for transmitting news with roughly similar identities among different newspapers. This similarity has been reflected clearly in online newspaper versions due to either missing the visual identity criteria or technological deficiencies, or both. This study tries to explore three main Egyptian national newspapers’ visual identity as represented in their Arabic typography traditionally and via the web. The paper also discusses the readers’ and designers’ feedback regarding visual identity and technological changes in a bid to rebrand online newspaper visual identity.

Solvents interactions with thermochromic print

The thermochromic ink composition includes a thermochromic microcapsules and an ink vehicle. Thermochromic microcapsules usually consist of at least three components – the colorant, colour developer and solvent. In order to achieve desired effect, the components are mixed in precisely determined proportions and encapsulated in a polymer envelope in order to protect him against external influences (Kulčar et al., 2010).