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Polyurethane (PU) is one of the most common and versatile polymers in many applications especially in the construction and automotive industry where the improvement of thermal stability and flame retardancy is crucial. As polyisocyanaurate (PIR) is well known to have a high decomposition temperature and phosphorus motifs are usually used as flame retardants in polymers, the introduction of PIR and phosphorus motifs in polyurethanes can lead to PUs with high thermal stability and flame retardancy. We investigated a synthetic pathway to introduce polyisocyanurate (PIR) and phosphorus motifs in polyurethanes via co-trimerization of 4,4′-methylene diphenyl diisocyanate (4,4′-MDI) and monoisocyanate, which was synthesized from the reaction between diethyl (hydroxymethyl)phosphonate (DEHP) and 4,4′-MDI. The resulting PIR-DEHP prepolymer was used to prepare PIR-DEHP elastomers in both solvent and solvent-free conditions. The elastomer with polyester polyol and 15 wt % 1,4-butanediol in the polyol component showed high char formation (25.5 wt %) and 55% reduction in the total heat release (THR) relative to the reference elastomer without PIR and phosphorus content. It is expected that the use of the PIR-DEHP prepolymer can be extended to other applications, such as rigid PU foams and compact thermosets where the flame retardancy and bulk reaction conditions are required.

Epoxy resins constitute a very significant portion of all high-performance plastics due to their excellent thermal and mechanical properties that appear in a wide range of applications. Nevertheless, traditional epoxy networks show limitations regarding chemical recycling due to their covalently crosslinked structures. The current methods to recycle epoxy resins are not indeed through sustainable ways, but this issue could be solved by developing smart monomers with functional groups, which can be switched between polymerized and depolymerized states. Herein, we developed two bio-based liquid monomers based on vanillin structures containing aldehyde, acetal, and oxirane-ring functionalities. These monomers were polymerized in solvent-free conditions using commercially available diamines, resulting in double-dynamic imine-acetal-containing thermosets. These networks combine the excellent properties of the traditional epoxy systems and dynamic polymers. Most importantly, such thermosets were fully depolymerized into vanillin, which can be reused for the preparation of original epoxy monomers, and a mixture of well-defined polyols, which was upcycled into high-performance polyurethane.

Polyurethanes (PUs) are widely used in many applications due to their versatile chemical and physical properties. To meet the increasing demands on PU with respect to intrinsic mechanical and thermal properties, they can be modified with thermally stable aromatic imide structures to form poly(urethane imide) (PUI). However, the preparation of PUI materials has been limited by the need for strong polar solvents, which hinder their industrial scale development. In this work, we prepared imide-containing isocyanate-terminated prepolymers via the reaction of polymeric aromatic or aliphatic isocyanates and pyromellitic dianhydride in completely solvent-free conditions. The subsequent PUI elastomers made from these prepolymers exhibited enhanced char formation and stiffness in comparison to the reference elastomers without imide structures, among which the aromatic PUI elastomer shows improved flame retardancy according to the initial cone calorimetry measurement. This work demonstrates the potential use of imide prepolymers in other PU applications where high thermal stability and flame retardancy are required. The solvent-free synthesis also paves a way for the large-scale production of PUI materials.

Polyurethane (PU) is used in a wide range of applications due to its diverse chemical and physical properties. To meet the increasing demands on thermal and mechanical properties of PU materials, polyisocyanurates (PIRs) have been introduced in PU materials as crosslinkers and due to their high decomposition temperature. We prepared a liquid PIR prepolymer with high PIR content by co-trimerization of 4,4’-methylene diphenyl diisocyanate (4,4’-MDI) and mono-isocyanates. The mono-isocyanate was synthesized via reaction between a 4,4’-MDI and a 2-ethyl-1-hexanol. The PIR prepolymer obtained was further reacted with long chain polyols and chain extenders in both solvent and solvent-free conditions, leading to PIR elastomers that exhibited good thermal stability with high char formation, and improved mechanical properties with much higher Young’s modulus. This work demonstrates that the liquid PIR prepolymer can potentially be used in various large-scale industrial applications.

Organic aerogels are an intriguing class of highly porous and ultralight materials which have found widespread applications in thermal insulation, energy storage, and chemical absorption. These fully cross-linked polymeric networks, however, pose environmental concerns as they are typically made from fossil-based feedstock and the recycling back to their original monomers is virtually impossible. In addition, organic aerogels suffer from low thermal stability and potential fire hazard. To overcome these obstacles and create next-generation organic aerogels, a set of polyimine aerogels containing reversible chemical bonds which can selectively be cleaved on demand is prepared. As precursors, different primary amines and cyclophosphazene derivatives made from bio-based reagents (vanillin and 4-hydroxybenzaldehyde) to elevate the thermal stability and reduce the environmental impact are used. The resulting polyimine aerogels exhibit low shrinkage, high porosity, large surface area, as well as pronounced thermal stability and flame resistance. More importantly, the aerogels show excellent recyclability under acidic conditions with high monomer recovery yields and purities. This approach allows for preparation of fresh aerogels from the retrieved building blocks, thus demonstrating efficient closed-loop recycling. These high-performance, recyclable, and bio-based polyimine aerogels pave the way for advanced and sustainable superinsulating materials.

A detailed study of the geometry, aromatic character, electronic and magnetic properties for a series of positively charged N-doped polycyclic aromatic hydrocarbons (PAHs) was performed. Magnetic properties of the examined molecules were analyzed by means of the magnetically induced current density calculated using the diamagnetic-zero version of the continuous transformation of origin of current density (CTOCD-DZ) method. The comparative study of the local aromaticity of the studied molecules was performed using several different indices: energy effect (ef), harmonic oscillator model of aromaticity (HOMA) index, six centre delocalization index (SCI) and nucleus independent chemical shifts (NICS). The presence of N-atoms in the inner rings was found to cause a planarity distortion in the studied N-doped systems. The geometric changes and charged nature of the studied N-doped systems do not significantly influence the current density and the local aromaticity distribution in comparison with the corresponding parent benzenoid hydrocarbons. The present study demonstrates how quantum chemical calculations can be used for rational design of novel PAHs and for fine tuning of their properties.

Derivati fulerena C60, zahvaljujući svojim jedinstvenim fizičkohemijskim ielektronskim svojstvima, koja proističu iz visoko konjugovanog π-sistema, činezanimljive gradivne elemente u sintezama složenijih ciljnih molekula. Različitimderivatizacijama hidrofobne ugljenične sfere dobija se niz proizvoda primenljivih uhemiji materijala, supramolekulskoj i medicinskoj hemiji. Imajući u vidu povećanjerastvorljivosti, kao i promenu stereoelektronskih osobina sa povećenjem broja adenadana fulerenskom jezgru, korisna je svaka metoda višestruke derivatizacije fulerena kojase odigrava pod kontrolisanim uslovima.Prato-va reakcija jedan je od najzastupljenijih vidova kovalentne modifikacijefulerena. U njoj nastaju fuleropirolidini, proizvodi jasno definisane strukture i čestiintermedijeri u složenim hemijskim tranformacijama fulerena. Ozbiljno ograničenje overeakcije predstavlja lako i neselektivno građenje bis- i tris-pirolidinskih adukata, kojiznačajno umanjuju prinose i čistoću monoadukata. S druge strane, bisadukti su sepokazali korisnima u nekim sferama medicinske hemije i elektrohemije.Regioselektivno dobijanje bisadukata fulerena upotrebom posebno dizajniranihpremošćenih supstrata bio je predmet interesovanja nekolicine istraživačkih grupa uproteklom periodu.U toku ovog rada sintetisan je niz alkil-premošćenih diglicina, u cilju dobijanjapremošćenih bis-pirolidinskih adukata fulerena u reakciji dvostruke Prato-vecikloadicije. U prvom delu rada, na supstratu premošćenom oktametilenskim nizom,optimizovani su reakcioni uslovi za dobijanje bisadukata. Optimalnim reakcionimuslovima podvrgnuti su i ostali supstrati, premošćeni alkil-nizovima dužine od 6 do 12C-atoma i utvrđena je zavisnost regioselektivnosti od dužine niza. Istim reakcionimuslovima podvrgnuta su i dva supstrata koji sadrže dve, odnosno tri etarske podstruktureu mostu i ispitan je uticaj kiseonikovih atoma u linkeru na selektivnost reakcije..., Due to their unique physicochemical and electronic properties, emerging fromhighly conjugated π-system, derivatives of the fullerene C60 are interesting buildingblocks in the synthesis of the more complex target molecules. Diverse derivatizationsof hydrophobic carbone sphere provide a wide range of products for the use inmatherial, supramolecular and medicinal chemistry. Since the increase of the numberof addends on the carbon core improves the solubility and varies the stereoelectronicproperties, each method of the controlable multiple derivatization of fullerenes ishighly useful.Prato's reaction is one of the most common methodes for the covalentmodification of fullerenes. The fulleropyrrolidines, products with well definedstructures, are frequently used as intermediers in further chemical transformations offullerenes. This reaction is limited with the easy and unselective formation of bis- andtris(pyrrolidino) adducts and, hence, decrease of the yields and the purity ofmonoadducts. On the other hand, bisadducts are very useful in some aspects of themedicinal and electrochemistry. During the recent period, the regioselective synthesisof the fullerene bisadducts via templated supstrates has been the topic of interest ofseveral researcher groups.In this work, a series of alkyl-tethered diglycines were synthesized andunderwent the Prato's biscycloaddition conditions in aim to obtain templatedbis(pyrrolidino)fullerenes. The first part of the work refers to the optimization of thebiscycloaddition conditions on the octamethylene-tethered substrate. Other diglycines,wearing from C6 to C12 alkyl-linkers, were subjected to this optimal reactionconditions and the correlation between the distribution of the regioisomers and thelenght of the linker is determined. Another two diglycines, wearing two and threeoxygen atoms in the tether, underwent the same reaction conditions in aim toinvestigate the influence of the etheric subunits on the selectivity of the reaction...

Derivati fulerena C60, zahvaljujući svojim jedinstvenim fizičkohemijskim i elektronskim svojstvima, koja proističu iz visoko konjugovanog π-sistema, čine zanimljive gradivne elemente u sintezama složenijih ciljnih molekula. Različitim derivatizacijama hidrofobne ugljenične sfere dobija se niz proizvoda primenljivih u hemiji materijala, supramolekulskoj i medicinskoj hemiji. Imajući u vidu povećanje rastvorljivosti, kao i promenu stereoelektronskih osobina sa povećenjem broja adenada na fulerenskom jezgru, korisna je svaka metoda višestruke derivatizacije fulerena koja se odigrava pod kontrolisanim uslovima. Prato-va reakcija jedan je od najzastupljenijih vidova kovalentne modifikacije fulerena. U njoj nastaju fuleropirolidini, proizvodi jasno definisane strukture i česti intermedijeri u složenim hemijskim tranformacijama fulerena. Ozbiljno ograničenje ove reakcije predstavlja lako i neselektivno građenje bis- i tris-pirolidinskih adukata, koji značajno umanjuju prinose i čistoću monoadukata. S druge strane, bisadukti su se pokazali korisnima u nekim sferama medicinske hemije i elektrohemije. Regioselektivno dobijanje bisadukata fulerena upotrebom posebno dizajniranih premošćenih supstrata bio je predmet interesovanja nekolicine istraživačkih grupa u proteklom periodu. U toku ovog rada sintetisan je niz alkil-premošćenih diglicina, u cilju dobijanja premošćenih bis-pirolidinskih adukata fulerena u reakciji dvostruke Prato-ve cikloadicije. U prvom delu rada, na supstratu premošćenom oktametilenskim nizom, optimizovani su reakcioni uslovi za dobijanje bisadukata. Optimalnim reakcionim uslovima podvrgnuti su i ostali supstrati, premošćeni alkil-nizovima dužine od 6 do 12 C-atoma i utvrđena je zavisnost regioselektivnosti od dužine niza. Istim reakcionim uslovima podvrgnuta su i dva supstrata koji sadrže dve, odnosno tri etarske podstrukture u mostu i ispitan je uticaj kiseonikovih atoma u linkeru na selektivnost reakcije..., Due to their unique physicochemical and electronic properties, emerging from highly conjugated π-system, derivatives of the fullerene C60 are interesting building blocks in the synthesis of the more complex target molecules. Diverse derivatizations of hydrophobic carbone sphere provide a wide range of products for the use in matherial, supramolecular and medicinal chemistry. Since the increase of the number of addends on the carbon core improves the solubility and varies the stereoelectronic properties, each method of the controlable multiple derivatization of fullerenes is highly useful. Prato's reaction is one of the most common methodes for the covalent modification of fullerenes. The fulleropyrrolidines, products with well defined structures, are frequently used as intermediers in further chemical transformations of fullerenes. This reaction is limited with the easy and unselective formation of bis- and tris(pyrrolidino) adducts and, hence, decrease of the yields and the purity of monoadducts. On the other hand, bisadducts are very useful in some aspects of the medicinal and electrochemistry. During the recent period, the regioselective synthesis of the fullerene bisadducts via templated supstrates has been the topic of interest of several researcher groups. In this work, a series of alkyl-tethered diglycines were synthesized and underwent the Prato's biscycloaddition conditions in aim to obtain templated bis(pyrrolidino)fullerenes. The first part of the work refers to the optimization of the biscycloaddition conditions on the octamethylene-tethered substrate. Other diglycines, wearing from C6 to C12 alkyl-linkers, were subjected to this optimal reaction conditions and the correlation between the distribution of the regioisomers and the lenght of the linker is determined. Another two diglycines, wearing two and three oxygen atoms in the tether, underwent the same reaction conditions in aim to investigate the influence of the etheric subunits on the selectivity o