Domagoj Vrsaljko

University of Zagreb Faculty of Chemical Engineering and Technology

This study utilizes additive manufacturing to fabricate a transparent microreactors with customizable internal structures, integrating optical sensors for pH detection. A sol-gel method was employed to prepare the pH sensor film, using tetraethoxysilane (TEOS) and phenyltrimethoxysilane (PTMS) as precursors, and methyl red as a pH indicator. Real-t...

This study investigates the fabrication of 3D-printed microfluidic devices for solid/liquid separation, focusing on additive manufacturing technologies. Stereolithography (SLA) and fused filament fabrication (FFF) were used to create microseparators with intricate designs optimized for separation efficiency. Model suspensions containing quartz sand...

Innovative electrospun pullulan/hemp protein isolate nanofibers (PUL/HP) with lecithin were successfully formulated for the delivery of phenylethanoid glycosides (PGs) from Teucrium montanum extract, at PUL to HP ratios of 80:20, 70:30, 60:40, 50:50, 40:60, and 30:70, based on total polymer mass (w/w). A higher HP content led to a more elastic beha...

In order to contribute to the demanded sustainability transparent poly(methyl methacrylate) (PMMA) composites with cellulose nanocrystals (CNC) up to high shares of 50 wt% were prepared by in situ radical polymerization in green solvent Cyrene. The weight average molecular weights of PMMA were in the range from 144,000 to 160,000 g mol ⁻¹ and the d...

The addition of static mixers within reactors leads to higher productivity of a process and an additional increase in mass and energy transfer. In this study, we developed millireactors with static mixers using stereolithography, an additive manufacturing technology. Computational fluid dynamics (CFD) simulations were conducted to study the flow, i...

Following the trend of transport decarbonization, biodiesel has become a promising alternative fuel option. Its production includes multiple steps, all of which can be time-consuming and energy intensive. Improving any of these steps could bring considerable environmental and economic benefits. The utilization of deep eutectic solvents (DESs) for g...

Intense pulsed light was investigated for partial photoreduction of AgCl in a poly(vinyl butyral) matrix to obtain a Ag/AgCl reference membrane. The membrane was deposited on both glassy carbon and inkjet‐printed silver electrodes giving all‐solid‐state reference electrodes. Regardless of the electrode material, a sufficient potential stability was...

In this study, spray drying was used as a technological solution for the valorization of Teucrium montanum extract into carboxymethyl cellulose-based delivery systems (CMC), individually or in combination with collagen, guar gum, gum arabic, and kappa-carrageenan. The results showed that the process yield and morphological properties were positivel...

The performance and degradation of nonwoven mulches made from viscose, jute, hemp fibers, and their blends with PLA fibers, subjected to field conditions, are investigated. This research explores the possible substitution of traditional agricultural polyethylene mulching agro foil with environmentally friendly biodegradable nonwoven mulches produce...

Synthetic esters are liquids used in the lubricant industry, but also in the electrical industry for insulation and heat transfer. In this work, synthetic ester was exposed to high temperatures to initiate and propagate the degradation reactions, study the degradation process and investigate the effect of paper and water on thermal degradation. Aft...

The innovation is the development of a millireactor system with a pH-responsive sensor coating on the surface of the millireactor channel. The pH-sensitive coating was prepared using the sol-gel process with a pH indicator added. Stereolithography (SLA), 3D printing technology for millireactor production is a novel approach for producing millireact...

The development of new materials is essential for advancing technology and improving the quality of life. With new materials, we can create products that are stronger, more durable, and more efficient. The ongoing research and development of new materials for 3D printing applications continue to drive innovation in various fields, leading to improv...

Antibiotics present common pollution in the environment, and they are often found in surface waters. Their presence or decomposition in water under natural sunlight can cause different unwanted consequences on the environment. In this paper, we report the application of 3D printed photocatalysts shaped as helix static mixers for tentative photocata...

The importance of facile and reliable route for preparing pure beta-tricalcium phosphate (β-TCP) is immense for bone grafting application. In addition to compositional purity, repercussions related with control over development of porosity, i.e. shaping, are even greater. In this study, we considered two facile synthesis paths from aqueous solution...

This paper investigates the possibility of integrating the combination of nanofillers, titanium dioxide (TiO2) and carbon nanotubes (CNT) into the thermoplastic polymer matrix. This combination of fillers can possibly modify the physico-chemical properties of composites compared to the pure polymer matrix. The composites were blended using the extr...

This paper investigates the possibility of producing monolithic catalysts for the degradation of aromatic volatile organic compounds by additive manufacturing technologies (3D-printing) using two different approaches. Stereolithography (SLA) was used to produce inert ceramic catalyst carriers and Fused Filament Fabrication (FFF) was used to prepare...

Insulating liquids (transformer oils) are dielectrics used in a wide range of electrical equipment and provide a medium for both insulation and cooling. During equipment operation, liquids are subjected to electrical and thermal stresses. With continued use, they chemically degrade and produce degradation products and aging markers. In this study,...

For good transformer condition assessment it is necessary to determine the condition of insulating materials, both liquid and solid. Transformer is reliable for as long as its insulation system resists deterioration. Therefore, thermal and oxidation stability are important characteristics of transformer oil. It is a measure of oil resistance for de...

Biodiesel produced from waste feedstocks can play a significant role in fighting climate change, improperly disposed waste and growing energy demand. Waste feedstocks such as used cooking oil have a great potential for energy production. However, they often have to be purified from free fatty acids prior to biodiesel production. Extractive deacidif...

Additive manufacturing offers simple and cost-effective production of highly customizable 3D-components. One particularly interesting technology is stereolithography (SLA), which enables the fabrication of micro- and milliscale reactionware using transparent materials. In this work, the influence of 3D-printing settings such as printing angle and l...

The flow regime inside the channel of 3D printed microreactors is defined by the surface properties of the channel walls. Polylactide (PLA) and acrylonitrile/butadiene/styrene (ABS) are two polymers that are the most common in additive manufacturing using fused filament fabrication, commonly known as “3D printing”. With the aim of developing new ma...

Industrial research departments and chemical engineering institutes have begun to adopt additive manufacturing technologies, such as stereolithography for producing special types of reactors for continuous production. Microreactors have been widely used to improve the mass and heat transfer processes between immiscible liquid-liquid phases, but wit...

Study explored high voltage electrical discharge (HVED) for recovery of bioactive compounds from Dalmatian sage. HVED parameters were: treatment time (3, 9 min), ethanol content (0, 25, 50%, v/v), voltage for Argon (15, 20 kV) and Nitrogen (20, 25 kV). Findings were compared to conventional extraction (CE) with assessment of total phenolic content...

Cilj ovog rada je istražiti utjecaj duljine naknadnog očvršćivanja i različitog kuta ispisa na primjenska svojstva poliakrilatne smole. Polazi se od hipoteze kako će različiti kutovi ispisa utjecati na mehanička svojstva, dok će različita vremena naknadnog očvršćivanja utjecati na mehanička i toplinska svojstva kao i otpornost ispisnog modela na ut...

This research investigated the impact of different processing temperature (extrusion at 160°C and 180°C) and the influence of the TiO2 and CaCO3 fillers on morphology, mechanical, and thermal properties of polylactide (PLA) blended with low‐density polyethylene (PE‐LD) and high‐density polyethylene (PE‐HD) in 90/10 weight ratio. The impact of the p...

Microreactor systems are reactors with three-dimensional structures which are under a millimeter in size. They are commonly fabricated by wet and dry etching, precision machining, laser treatment, blasting and lithographic techniques. Additive manufacturing technologies have been overlooked in this area. This paper presents a part of research relat...

We report the first cocrystal as an intermediate in a solid state organic reaction wherein molecules of barbituric acid and vanillin assume a favorable orientation for the subsequent Knoevenagel condensation.

Mikroreaktori su reaktorski sustavi izvedeni u mikroskopskom mjerilu, a zbog svoje velike međufazne površine imaju prednosti u odnosu na klasične – makroreaktorske sustave. Odabir materijala za izradu mikroreaktora ovisi o vrsti reakcije koja se provodi u sustavu, kompatibilnosti otapala i materijala, mehaničkim zahtjevima te o cijeni i dostupnosti...

Treatment of household wastewater loaded with hair colorants by means of solar photocatalysis using TiO2-coated polyester/wool textile has been reported recently. In this work, the attributes of immobilized photocatalyst were enhanced; a textile support (polyester/wool blend fabric) was pre-treated by atmospheric and low pressure oxygen plasma prio...

A novel method for designing hydrophobicity of the polylactide / low-density polyethylene (PLA/PE-LD) blends by creating specific surface topography is proposed. In order to increase hydrophobicity by changing the topography of two-phase PLA polymer blend surface, blends are etched by using ICP before the fluorocarbon-based coating treatment done i...

OSVRTI Znanstveni projekt "Razvoj materijala za 3D-tiskanje mikroreak-tora"-3Dmicroreactors (eng. "Development of materials for 3D printing of microreactors") istraživački je projekt koji u razdoblju od 1. srpnja 2015. do 30 lipnja 2018. kroz program "Uspostavni istraživački projekti" financira Hrvatska zaklada za znanost. Aditivna proizvodnja (eng...

This research underlines the potential of employing emulsion/internal gelation encapsulation in alginate and pectin hydrogels for the simultaneous delivery of hydrophilic (polyphenols from dandelion (Taraxacum officinalis L.) extract) and lypophilic (ß-carotene) compounds. The approach of reinforcing alginate and pectin hydrogels by whey proteins a...

This article describes the use of commercial silica (SiO2) and calcium carbonate (CaCO3) nanofillers as compatibilizers in immiscible polylactide/low-density polyethylene (PLA/LDPE) blends. The general aim of the study was to investigate the possibilities of replacing standard commodity plastics such as LDPE based on non-renewable mineral oil resou...

The influence of untreated and stearic acid surface pretreated calcium carbonate (CaCO3) nanofiller (U1 – untreated CaCO3 and U1S2 – stearic acid treated CaCO3) on the properties of polyurethane/poly(vinyl acetate) (PUR/PVAC) polymer blends was investigated. Adhesion between fillers and polymers in the polymer blend composite, and filler position i...

Optical sensors for application in innovative wearable sensing systems such as textile-integrated systems and wireless sensor platforms rely on the development of low-cost multifunctional materials compatible with standard fabrication technologies. We are developing optically responsive pH sensitive sol–gel coatings for integration with a mobile wi...

The stabilising effect of hydrotalcites on rigid (UPVC) and flexible (PPVC) has been investigated for samples cut from compression moulded sheets oven aged at 180 °C using UV–visible and Raman spectroscopies, solubility, and X-ray diffraction, and by observing their discolouration. Hydrotalcite improves the long term stability of PVC and inhibits c...

The analysis of particular case studies of products in chemical engineering by taking into account demands from the market for improved quality behavior may help in solving the problem and looking for new products with added value in compliance with the customers' requirements. This paper partly investigates the problem of the negative appearance o...

Modeling of the sonochemical reactors presents a great challenge due to issues related to the experimental investigation and description of the primary effects of the ultrasound. The main idea proposed in this work was to establish an algorithm consisting of the viable laboratory analyses and basic elements of chemical reaction engineering. In this...

Mechanical and morphological properties of composites containing styrene—acrylonitrile (SAN) copolymer, ethylene— propylene—diene (EPDM) polymer, and different types of precipitated calcium carbonate (PCC) were investigated and their properties were analyzed in regard to PCC surface properties and the way of sample preparation (with or without use...

Properties of samples containing polyurethane (PU), poly(vinyl acetate) (PVAc) and nanosize particles of calcium carbonate (CaCO3) are correlated with concentrations of these components. Interphase phenomena in PU/PVAc/CaCO3 nanohybrids have been studied before, we focus here on wear and scratch resistance. In addition to polymer blends containing...

While attention of academia and industry on materials properties is largely focused on mechanics, wear causes losses in industry at least not smaller than fracture caused by mechanical deformation. We discuss the importance of tribology for polymer-based materials (PBMs). Traditional tribology developed originally for metals cannot be applied to PB...

Simple mid-infrared spectroscopy based methods for obtaining complete thermal characterization of polymers are proposed. In addition to some previously described structural transformations, such as melting and thermal decomposition, the proposed IR (transmittance and attenuated total reflectance) based thermal analyses can also determine glass tran...

Tribological investigations can be conducted at several size scales, from micro-level to nano-level. On this basis we can develop correlations between viscoelasticity, brittleness and tribological behaviour of polymer-based materials that reflect the effects of composition, orientation in the magnetic field and surface treatments. The relationship...

Based on the philosophic ideas of O. Spengler and Aristotle it has been determined that polymers are ancient since they reach back all the way to the origin of the basic natural organic and inorganic polymers. At the same time it has been noted that the word polymers is frequently used as a common name for plastics and elastomers. Since the basic n...

Tribološka ispitivanja mogu se provesti na nekoliko razina, od mikrorazine do nanorazine. Na toj osnovi mogu se istražiti korelacije između viskoelastičnosti, krhkosti i tribološkog ponašanja materijala na osnovi polimera koje odražavaju utjecaje sastava, orijentacije u magnetnom polju i obrade površine. Relacija između stupnja viskoelastičnog opor...

Polazeći od fi lozofskih misli O. Spenglera i Aristotela, utvrđeno je da su polimeri prastari, jer sežu tamo do postanka osnovnih prirodnih organskih i anorganskih polimera. Istodobno je uočeno da se riječ polimeri učestalo upotrebljava kao zajedničko ime za plastiku i elastomere. Od osnovnih prirodnih organskih polimera: bjelančevina, nukleinskih...

In the first part of this article the foundations and the importance of tribology in the materials science and materials engineering are provided with the emphasis on polymeric materials. The basic principles are described together with the new experimental approach for investigation of the scratch resistance that take into account the viscoelastic...

U prvom dijelu rada o osnovama i važnosti tribologije u prirodnim znanostima koje se bave materijalima i u inženjerstvu materijala naglasak je na onom dijelu tribologije koji se bavi polimernim materijalima. Opisana su osnovna načela, uz navođenje važnosti kvantitativne ispitne metode višestrukog brazdanja površine uzimajući u obzir viskoelastičnos...

Improvements in adhesive properties at the interface in nanocomposites, with respect to the standard microcomposites, are a consequence of the great specific surface area of nanofillers and established interactions at nanolevel. An overview of investigations related to the interface and material properties in the conditions of the changed parameter...

The interface in particulate filled polymer systems determine to a large extent, the mechanical and morphological properties of composites and polymer blends. The present contribution describes surface free energy measurements and calculations of adhesion parameters at the interface in poly(vinyl acetate) (PVAc) and polyurethane (PU) composites as...

Polyurethane (PU) and poly(vinyl acetate) (PVAc) are partially miscible polymers. The aim of this study was to investigate the influence of untreated and surface pretreated calcium carbonate (CaCO3) on the interphase properties of PU/PVAc polymer blends with possible compatibilization effects when the conditions of effective adhesion are achieved....

Effects of untreated calcium carbonate (CaCO3) of different sizes, and silane pretreated CaCO3 fillers on properties of polyurethane (PU) composites (PU/CaCO3) were investigated. Small angle X-ray scattering research of phase structure and morphology has shown significantly stronger influence of the CaCO3 nanofillers than the CaCO3 microfiller on a...

Cilj ove disertacije bio je istražiti utjecaj neobrađenog i površinski predobrađenog kalcij karbonatnog (CaCO3) mikro- i nanopunila na međupovršinska svojstva poliuretanskih (PU) kompozita i poliuretan/poli(vinil-acetat)) (PU/PVAc) polimernih mješavina. S ciljem da se modificira međufaza između punila i matrice, CaCO3 je predobrađen aminopropil-tri...

In the present paper, the changes at interface between calcium carbonate (CaCO3) and polyurethane (PU) matrix in correlation to the mechanical and morphological properties were investigated. The effect of the untreated CaCO3 microfillers versus nanofillers and/or selected silane pretreatment of nanofiller surface were followed. Correlation between...

Poboljšanje adhezijskih svojstava na međupovršini u nanokompozitima, u odnosu na standardne mikrokompozite, posljedica je velike specifične površine nanopunila i uspostavljenih interakcija na nanorazini. U ovom radu dan je pregled rezultata istraživanja svojstava međupovršine i svojstava materijala u uvjetima promjene parametara adhezije kontrolira...

Improvements in adhesive properties at the interface in nanocomposites, with respect to the standard microcomposites, are a consequence of the great specific surface area of nanofillers and established interactions at nanolevel. An overview of investigations related to the interface and material properties in the conditions of the changed parameter...

Outdoor weathering of unprotected wood can cause severe surface degradation. This preweathering before finishing can lead to chemical and physical changes on the wood surface that can influence wood-coating interface. The change in wettability of wood surface with weathering and a change in adhesion strength of acrylic water based coating on prewea...

In this paper results of the calcium carbonate nanofillers and microfillers addition, as well as influence of the filler surface pre-treatment with stearate and with γ-aminopropyltrietoxysilane (AMPTES) on the properties of the poly(vinyl acetate) and polyurethane composite films respectively, are presented. The results indicate that morphology, fa...

In this work we have investigated the effects of CaCO3 nanofiller pretreatment on the properties of polyurethane (PU) composites prepared by a mixing procedure. The aim was to enhance interactions at the matrix/filler interface and to improve the distribution of the filler in the polyurethane matrix. CaCO3 nanofiller was treated with two different...

Poly(vinyl acetate) (PVAc) composites were prepared by different approaches, namely (i) by mechanical mixing of untreated CaCO3 and PVAc, (ii) by mechanical mixing of CaCO3 pre-treated by irradiation polymerization in the presence of vinyl acetate, and (iii) by in situ emulsion polymerization of VAc in the presence of untreated CaCO3 nanofiller. Th...