Waterborne polyurethane dispersions (PUD) are promisories materials in adhesives and coatings industry because of the global concern in reducing the amount of volatile organic compounds. Combinations of PUD with acrylic polymers (AC) are an interesting option to reduce costs, obtaining hybrid dispersions (PU/AC) with tailored and improved properties. In the present work, saturated (PBA) and unsaturated polyesters (PBAM) were synthesized from adipic acid, butanediol and maleic anhydride, they were used as polyol component for obtaining hybrid polyurethane aqueous dispersions (PU/AC), using isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as a source of isocyanate and internal emulsifier respectively. The vinyl-acrylic fraction was composed by a styrene (ST) and butyl acrylate (BA) mixture of monomers (1:1 wt. ratio) at 40 % wt respect to the final polymer. Unsaturations in PBAM allows obtaining hybrids materials by internal grafting for comparing them with interpenetrated networks (IPN) method in which PBA was used. The incorporation of the vinyl-acrylic fraction in the hybrid materials, allows obtaining more stable dispersions with solids content up to 28 % wt., average particle sizes of 70 nm and ζ potential values of -75 mV, respect to the bare PUD, in which the average particle size was up to 300 nm. This work demonstrated that hybrids materials obtained by grafting process showed better adhesive capacity on a film of approximately 10 μm applied on stainless steel sheets tested by cross-cut and improved thermal stability compared to IPN hybrid films. Acording to the results, it is possible to take advange of the performance of grafted hybrid materials for applications in adhesive and coatings industry respecto to the materials obtained by IPN.
Anny Catalina has completed her Chemist degree in the Universidad de Antioquia, Colombia. Currently, she is doing her Master´s studies in the same University using the Student Instructor Scolarship. She is member of Laboratorio de Investigación en polímeros.
Resins derived from dimethacrylates, such as urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEDGMA) and bisphenol A glycidylmethacrylate (BIS-GMA), are widely used in dental industry as photopolymerizable resins in processes of dental restoration and adhesives1,2. One of the main drawbacks of these resins is the high viscosities of the resins, which is overcame by the addition of TEGDMA up to 20 wt. % in most of dental resins formulation. However, this monomer increases the volumetric contraction of the matrix, which may generate secondary caries. In order to solve this drawback, it is proposed to incorporate a monomer which reduces the volumetric contraction and additionally has antibacterial activity3,4. In this work a methacrylic monomer derived from 5-Chloro-2-(2,4-dichlorophenoxy)phenol (TCA) was synthesized and incorporated in a serie of photopolymerizable dimethacrylate resins based on triethylene glycol dimethacrylate and urethane dimethacrylate with the aim of reducing de volumetric contraction and conferring antibacterial properties to the final resins. The physicochemical results show that when the TEGDMA is replaced by the TCA the surface become more hydrophobic, hence, the contact angle of the polymer increases, which is corroborated by the diminishing of the amount of water absorbed in polymeric probes. The incorporation of TCA to the polymeric matrix improved mechanical properties, the maximum load at break and the flexural modulus increased more than 60 %, when UDMA is partially replaced by TCA at 20 wt. %, maintaining TEGDMA resin amount constant. The decomposition temperature and the strength of adhesion are also considerably improved by the incorporation of TCA. Monomer and homopolymer presented enhanced antibacterial activity compared to bare resins. This study allows to consider TCA as novel monomer for resins and dental adhesive formulations, where physical, mechanical and antibacterial properties must be enhanced.
Victor H. Orozco completed his PhD from Universidad de Antioquia, Colombia. He is the assistant professor of the same University in the Chemistry Institute. He has been working with biopolymers, biodegradable polymers for drug transport and delivery. Now day, he is coworking in an emerging reasearch group dealing with new monomer for dental and coating applications with antibacterial properties.
The polyhydroxyalkanoates (PHAs) are thermoplastic biopolymers obtained by bacteria that have mechanical and thermal properties similar to polypropylene. From an industrial application point of view, the PHAs have higher production costs compared to those polymers obtained from oil industry, as polypropylene and polyethylene. However, a promising application for these materials deals with their use as ecosorbents, for sorption of target molecules of pharmaceutical, industrial and analytical interest. In this work two different PHAs has been obtained from Ralstonia eutropha by using i) glucose syrup and ii) a mixture of molasses-vinasses, as raw material. The polymer produced from molasses-vinasses was chemically modified with hydroxyethyl-methacrylate (HEMA). These materials were dissolved in chloroform and precipitated by using methanol at high shear rate in order to obtain a suspension of polymer particles, these particles were dried and packed in cartridges for sorption of gentian violet solution at 14,5 ppm for retention tests. Results have shown that independently on the raw material, a copolymer of poly (hydroxybutirate-co-hydroxyvalerate) is obtained. However, when molasses-vinasses is used, the copolymer formed has a higher proportion of hydroxyvalerate group, which was determined by H-NMR and FTIR. These changes in the structure imply that the material obtained is more hydrophobic and has a lower crystallinity. An entire retention of the gentian violet dye is obtained in all copolymer tested, but the rupture volume was higher for the PHAs produced from molasses-vinasses, followed by glucose syrup and ended with chemically modified polymer. This corroborates the change in the polymer structure due to the different biosynthesis condition and chemical treatments.
Luis F. Giraldo has completed his PhD in chemical science from University of Antioquia, Colombia. He is the director of the Laboratorio de Investigación en Polímeros in the same University.
The development of hybrid materials containing layered silicates or graphene oxides received increased attention in the last decade. In the same time, different polymeric matrices like epoxy resins, methacrylate or thermoplastic polymers, were used together with silicates or graphene oxides in order to obtain high performance materials with different applications. Researchers has been using graphene oxyde to create a range of different composite structures and catalyse numerous reactions [1, 2]. Moreover, the modification of these inorganic or hybrid compounds with different reactive functionalities was reported and the obtained reactive molecules exhibit a positive influence on various polymeric matrices . Aiming to improve the compatibility between the organic and the inorganic phase, thus obtaining nanocomposites with the exfoliated structure, we propose a new route to synthesize hybrid materials based on montmorillonite (MMT) and graphene oxide (GO). A new strategy for the synthesis of complex reinforcing structure formed by exfoliation of silicate layers with amine modified GO was used. The optimization of the functional silicates/graphene oxides reaction as well as the subsequent polymer nanocomposites synthesis will be discussed by means of Raman, XRD and XPS structural characterization. The thermal and mechanical properties of the resulting hybrid materials will be presented. Acknowledgement: Authors aknowledge Ministry of National Education for fundind through project PN-III-P1-1.2-PCCDI- 2017-042 References:  Hassan Ahmad, Mizi Fan, David Hui, Composites Part B: Engineering, 2018 , DOI: 10.1016/j.compositesb.2018.02.006  Dema A.Almasri, Tarik Rhadfi, Muataz A.Atieh, Gordon McKay, Said Ahzi, Chemical Engineering Journal, 335, 2018, 1-12  A. Leszczyńska, J. Njuguna, K. Pielichowski, J.R. Banerjee, Thermochimica Acta, 453 (2), 2007, 75-96
Celina Maria Damian has completed her PhD and postdoctoral studies at University Politehnica of Bucharest, Romania. She is project leader within the Advanced Polymer Materials Group. She has published more than 40 papers regarding synthesis and properties of epoxy and carbon nanostructures based materials. Other research interests include renewable polymers and reinforcing agents.
The wood components like celluloses, hemicelluloses or lignin being play important role in many industries such as pulp and paper industry, textile industry, pharmaceutical industry, food industry and in agriculture. The goal of this study is to examine the possibility of using the substances derived from black liquor of wood as valuable biomaterials for example in combination with microcrystalline chitosan (MCCh). Lignin fractions were isolated from black liquor (the by-product of pulp & paper industry) using different reaction conditions. As a result of the study various MCCh/lignin polymer biocomposites were prepared. The interactions between the two polymers are important for preparation of novel biopolymer materials that can be applicable in medical and hygienic products. The hemicelluloses (for example GGMs) were extract from black liquor (after removal of lignin). The obtained hemicelluloses were characterized by different chemical composition in terms of glucose, galactose and mannose ratios, and by different average molecular weight, depending on the method of isolation. The studies are being conducted to evaluate the protective and growth stimulating properties of the isolated hemicelluloses with respect to selected plants. The test compositions were prepared on the base of chitosan and extracted hemicelluloses. It has been found that the compositions containing hemicelluloses stimulate germination of plant seeds. The effect of the hemiceluloses addition to the certain fibrous cellulose products on their barrier properties towards air and water vapour was also studied. The fibrous cellulose products containing hemicelluloses (GGMs), showed decreased permeation ability for various gases including air and water vapour.
Ewa Kopania has completed her PhD from Technical University of Lodz. She is assistant and Head of the Cellulose Team. She has many years experience in carrying research and development activities in the area including in particular issues related to the use of technological processes and biorafination plant materials and extraction cellulose fibers, lignin and hemicelluloses. Author and co-author of over 25 publications in scientific journals and 3 patent applications. Participation in the realization of the 7 research projects, including management 3.
Biopolymers including the most abundant cellulose are in many respects attractive raw materials since they are biodegradable, suitable for recycling or composting and are considered the best replacement for packaging materials based on petroleum, from the point of view of the use of natural resources, energy management and impacts on the environment. Many research works focus on the use of cellulose fibres and microfibrils as a reinforcement of polymer composites, due to their availability and mechanical properties. Cellulose, however, has a limited use in composites due to its hydrophilic character, therefore much attention is paid to the production of cellulose derivatives with increased hydrophobicity. One of the well-known methods of obtaining such derivatives is esterification using fatty acids. Chemical modification of polymers is harsh for the environment and is not always easy to control, and in the case of cellulose fibers it can cause yellowing and weight loss. That is why scientists are looking for alternative methods to chemicals. Their attention, for many reasons, draws the use of enzymatic catalysis. The aim of the work was research on the process of surface esterification of cellulose fibres with oleic acid. The esterification reactions of fibres isolated from wood cellulose were carried out in organic solvents using lipase enzymes as a catalyst. The effect of reaction time, reaction environment (type of solvent), reagent ratio and type of biocatalyst on the course of the esterification process (cellulose substitution rate, reaction yield) were investigated
Janusz Kazimierczak has graduated from Lodz University of Technology. He is a senior research and technical specialist at the Institute of Biopolymers and Chemical Fibres. He has published more than 12 papers in peer reviewed journals.
Plastic waste is one of the biggest enviromental problems concerning society last decades. Interest in development of biodegradable materials to replace conventional petroleum based polymers is considerably growing nowadays. Starch is considered a great candidate due to its wide availability, biodegradability and low cost but, it has some disadvantages that must be solved before introduce it in the market: they must be converted into a thermoplastic starch (TPS) which can be processed with the conventional techniques and they have poor thermal and mechanical properties which are really affected by ageing. To get the TPS, the use of a novel plasticizer agent (isosorbide) was necessary, as well as the application of thermal and shear treatments. Completely green plasticized compounds from a maize starch were obtained by melt processing using internal mixer. To enhance TPS properties, different proportions of microcellulose (MCC) was added, resulting in reinforced TPS/MCC composites. Neat TPS and reinforced TPS/MCC, both fresh and aged (5 months storage) samples, were analysed by different techniques. The influence of both, storage time and filler concentration, in behaviour and properties of different compounds was the final aim of this work. Morphology of the TPS and TPS/MCC compounds was followed by scanning electron microscopy (SEM). The evolution of chrystalline structure during plasticization process and ageing process were followed by X-ray diffracation analysis (DRX). Finally, mechanical properties was studied in a dinamic mechanical analyzer (DMA).
Dr. Belén Montero has completed his PhD in polymer science and technology from University of A Coruña (UDC), Spain. She nowadays develops her activity as a teacher in the department of physics and earth science in the UDC. At the same time, she develop her investigation as a member of the “Polymers Group” in the same university. She has published several papers in reputed journals and has attended to several international conferences related to the polymer science field. Her last investigation works has been focused in the development of biopolymeric materials.
Nowadays plastic waste materials, especially plastic bags, are accumulating in the environment due to their low degradability. For being more eco-friendly, plastic materials with specified life periods are required which can degrade into non-harmful materials at the end of their service life. Common plastics, such as Polyethylene (PE) and Polypropylene (PP), undergo peroxidation slowly due to added antioxidants and stabilizers. Linear low-density polyethylene (LLDPE) is especially significant as it is widely used for many applications. This synthetic polymer is normally not biodegradable until it is degraded into low molecular mass fragments. In the present work various photo-catalytic additives especially titanium dioxide (TiO2) were used as prooxidants in order to make LLDPE degradable after working period. Anatase and Rutile TiO2 were thermally blended with LLDPE. Results showed that photo degradation leads to physical embrittlement of the blends and leaves a porous and mechanically weakened plastic. This will accelerate the final degradation of the polymer by diffusion of oxygen, moisture, and enzymes into the porous polymer matrix. The carbonyl index of the anatase TiO2 blended LLDPE films increased continuously over the irradiation period while their tensile strength decreased. Also the films showed a weight loss about 11-15 %.
Soheyl Khajehpour-Tadavani has completed his PhD from Islamic Azad University, Iran. He is operation supervisor for producing Methanol at Zagros Petrochemical Company (Z.P.C.) as the biggest Methanol plant in the world in Asaluyeh, Iran. .Besides, he is a member of the research and development group for Methanol to Olefin (MTO) project and Methanol to Propylene (MTP) project studies.
Despite very good properties, increased use of synthetic packaging films has led to serious ecological problems due to their non-biodegradability. Although their complete replacement with eco-friendly packaging films is just impossible to achieve, the limitation related to the use of synthetic polymers in food packaging industry became an important issue and the main driving force for rapid development of innovative bio-based systems. There are several alternatives to petroleum-based polymers among which polysaccharides recently became very important in food packaging industry due to their edibility, good barrier properties toward gases and antimicrobial activity, which contribute to the improvment of food quality and extending of shelf-life. The aim of this paper was to propose a chitosan-based (Ch) films, prepared by solvent-casting method, as an alternative to non-biodegradable packaging films. Bearing in mind that mixing of polymers is important in order to improve film properties or to reduce production cost, the addition of poly(vinyl alcohol) (PVA) in chitosan film formulation was investigated. The obtained Ch-PVA films were transparent and colorless. In addition, the presence of poly(vinyl alcohol) significantly affected mechanical and barrier properties, whereas no significant effect on thermal properties was observed. The tensile strength and elongation at break decreased with increase of PVA content. On the other hand, the water vapor permeability of prepared films increased, but the values were still acceptable for the food packaging material. Although investigated films showed satisfactory properties, further efforts should be done to make them competitive with commercially available food package materials.
Melina Kalagasidis Krušić has completed her PhD from Faculty of Technology and Metallurgy (FTM), University of Belgrade, Belgrade, Serbia. She is Full Professor at FTM, Head of the Polymer Research Laboratory (www.polymlab.tmf.bg.ac.rs) and Secretary of the Serbian Chemical Society and member of the Society Presidency. She has published more than 44 papers in reputed international and national journals and 72 papers at scientific conferences (her papers have been cited more than 470 times); supervised 4 PhD thesis and 64 master and diploma thesis; participated on several national and international scientific projects.
One of the major problems of modern-day society is to maintain food quality for longer period. Hence, scientific attention is focused on finding suitable compounds that help protecting food from bacteria growth and prolonging its shelf-life. Substance that could meet these requirements is a natural compound thymol. However, thymol is slightly soluble in water limiting its application in the food industry. On the other hand, its solubility in supercritical carbon dioxide (scCO2) might be as high as 31.3 kg/m3 making supercritical impregnation a promising method for thymol incorporation into polymeric materials used for manufacturing of food containers that prolong freshness and quality of food. The present study provided new data on supercritical impregnation of thermoplastic starch (TPS) and thermoplastic starch/poly(ε-caprolactone) blend (TPS-PCL) with thymol. Impregnation experiments were carried out with scCO2 at 40, 70, and 100 °C and 30 MPa in a high-pressure view cell, while the time of impregnation was in the range from 1 to 20 h. Considering typical food storage conditions, thymol release kinetics was followed at 6 and 25 °C, using spectrophotometric measurements at 274 nm. Satisfactory high impregnation yields were obtained in the case of TPS-PCL (between 4.6 and 15.4% depending on impregnation time and temperature). However, in the case of TPS lower impregnation yields were attained, with maximal value of 3.8% (6 h of impregnation at 70 °C). Still, thymol release time from both materials was 10 days indicating high potential of these materials for application in food industry as a smart food packaging.
Dr. Marija Lučić Škorić has completed her PhD from Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia. She is working as Reasearch Associate in Innovation Center of Faculty of Technology and Metallurgy since 2012. She is a member of Polymer Research Laboratory team ( www.polymlab.tmf.bg.ac.rs). She has published 10 papers in reputed international and national journals and 16 papers at scientific conferences. Her papers have been cited more than 45 times.
In the period of high technological development, one of the important issues that are waiting to be solved is the protection of metal equipment against corrosion. In modern scientific practice, among the methods of corrosion protection, the use of inhibitors is most effective. The purpose of our research is to create highly effective preservative fluids based on mineral oils with the use of modified by imidazolines phenol-formaldehyde oligomers. Separately, phenolic oligomers and organic compounds with nitrogen functional groups are important as inhibitors to prevent the corrosion process. Thus, in the linear structure of phenol-formaldehyde oligomers, the protective effect determines the presence of polar hydroxyl, methylol groups, a delocalized p-electron cloud of aromatic nuclei, and in imidazoline molecules, amine fragments with an unshared electron pair at nitrogen atoms, which provide high adhesion on the surface of metal structures in the process operation. Taking into account the foregoing, in order to enrich with nitrogen-containing functional groups, the process of modification of phenol-formaldehyde oligomers by imidazolines has been carried out. To ensure good solubility of the products obtained in mineral oils, monoalkylphenols containing a sufficiently long hydrocarbon chain of C8-C12 were used as a starting component. Synthesis of imidazolines was carried out by the interaction of polyamines with fatty acids isolated from sunflower and corn oil by saponification followed by treatment with concentrated hydrochloric acid. Polyethylenepolyamines and its low-boiling fractions, diethylenetriamine and triethylenetetraamine were used as polyamines. The process was carried out in two stages at the appropriate temperatures. The starting components were taken in molar ratios of 1: 1-2, 1: 1 and 1: 1, respectively, in order to preserve the reactive amine groups for further modification. The modification process was carried out by polycondensation of the required amount of monoalkyl (C8-C12) phenols and formaldehyde (in 33% aqueous solution in formalin) in an acidic medium at a temperature of 98-100 0С until the appearance of a turbidity indicating the formation of an oligomeric chain, then the reaction mixture was again heated to 98-100 0C. At this temperature, the reaction was continued until the resin was formed. The structure of monoalkyl (C8-C12) phenol formaldehyde oligomers modified with imidazolines based on plant acids was studied by infrared spectroscopy. The physico-chemical properties, thermal stability and molecular-mass distribution of synthesized oligomers have been determined.
I am Narmina Rufat Abdullayeva in 2004 graduated from the Azerbaijan State Oil Academy's Masters Degree in Chemistry and Technology with a degree of honours and continued research in Institute of Petrochemical Processes Azerbaijan National Academy of Sciences. I am successfully defended PhD in 2010 on the synthesis and research of fuel components and additives based on natural organic acids. I have PhD degree in technical sciences on the specialty "Fuel chemistry and technology". Now I am work on position of leading researcher in Institute of Petrochemical Processes. I am always worked diligently on continuing and expanding the research work in the current position and actively participated in the organization and implementation in projects in field of technical sciences. At the moment, I am conduct research in the creation of new corrosion inhibitors for preservative liquids based on phenol-formaldehyde oligomers and mineral oils. The results of my researches were reflected in 71 published scientific papers. Chairman of the "Young Scientists and Specialists" board of Institute of Petrochemical Processes. In work with young people I am initiates their participation in various local and international conferences and events, organizes projects and events under the state program "Azerbaijan Youth". Currently a member of the Big Scientific Council in Institute of Petrochemical Processes.
The various molecular interactions of mussel foot proteins, especially the miraculous Dopa chemistry, have inspired the development of many mussel-inspired materials such as wet adhesive and functional coating by Dopa-mediated adhesion and cohesion mechanism. The unique catecholic group in Dopa, which can strongly interact with a variety of organic and inorganic substrates via electrostatic forces, stacking, coordination and hydrogen bonding, was known to be the key component responsible for the strong adhesion. Efforts in the related research have thus been dominated by the simple peptide and polymer constructs containing catechol group or molecular dopamine. Herein we present a mussel-inspired synthetic poly(amino acid)s, specifically polyaspartamides, modified by dopamine or histamine together with other hydrophilic/hydrophobic pendants and their metal-coordinated hydrogels as a novel adhesive and self-healing gel potentially useful in many biomedical and industrial applications. Different metal-ions such as Fe(III), Cu(II), Ni(II), Zn(II), Ag(I) were used to prepare the metal-coordinated polymeric gel in aqueous solution. The related gels showed self-healing behavior and also good adhesive property on a variety of substrates such as glass, metal and plastics. In addition, the in-situ preparation of silver nanoparticle, without reducing agent, from the silver-coordinated polymer & gel was interestingly investigated in order to develop an anti-bacterial material based on this biomimetic catechol(or imidazole)-conjugated polymer. Owing to the versatile adhesive property and the nontoxic biocompatible nature of raw material, this novel class of polymeric gel has potentially useful in biomedical applications including tissue adhesive, sealant and also as a general-purpose industrial glue.
Ji-Heung Kim is a professor of Chemical Engineering at Sungkyunkwan University(SKKU) since 1992. He received a BS degree from Seoul National University, a MS degree from Korea Advanced Institute of Science and Technology (KAIST), and a PhD degree from Rensselaer Polytechnic Institute, NY (USA) in 1991. Then he was a postdoctoral research associate at the University of Massachusetts, Amherst (USA). He spent one year as a visiting scientist at the Science University of Tokyo (Japan) in 1997, and also at the University of Queensland (Australia) in 2005. He served as editor of Polym-Korea journal (2007~2012) and as director of Polymer Technology Institute of SKKU. His current researches are focused on the synthesis of novel functional polymer, smart and stimuli-responsive hydrogel, metal-coordinated self-healing gel, bio-inspired adhesive polymers, for various biomedical and industrial applications.