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Cilj ovoga rada bio je ispitati svojstva čistih komponenata polilaktida (PLA-S, PLA-N), polietilena visoke gustoće (PE-HD) i polietilena niske gustoće (PE-LD). Također, su ispitana svojstva pripremljenih polimernih mješavina PLA-S/PE-HD, PLA-S/PE-LD, PLA-N/PE-HD i PLA-N/PE-LD 95/5 i 90/10 bez i uz dodatak punila (TiO2, silika). Uzorci su umješavani u Brabender gnjetilici. Određena su mehanička i toplinska svojstva čistih komponenata i pripremljenih polimernih mješavina. Također, je ispitana morfologija na temelju mehaničkih svojstava odabranih uzoraka. Snimljeni su FTIR spektri čistih komponenata. Na temelju dobivenih rezultata zaključeno je da polimerne mješavine bez dodatka punila imaju manju prekidnu čvrstoću i rad loma u odnosu na čiste komponente. U mješavinama PLA-N kao bolje punilo se pokazao TiO2, dok je u mješavinama s PLA-S kao bolje punilo odabrana silika. Proučavanjem morfologija mješavina, zaključeno je da najveći utjecaj na mehanička svojstva ima raspodjela veličina čestica i dispergiranost faza. The aim of this study was to determine the properties of 95/5 and 90/10 PLA-S/PE-HD, PLA-S/PE-LD, PLA-N/PE-HD and PLA-N/PE-LD polymer mixtures prepared without and with filler addition (TiO2, silica). Also, properties of pure polylactide (PLA-S, PLA-N), high density polyethylene (PE-HD) and low-density polyethylene (PE-LD) have been tested. Samples were blended in the Brabender mixer. Mechanical and thermal properties of pure components and prepared polymer blends were obtained. The morphology of selected samples was tested. FTIR spectra of pure components were recorded. Based on the obtained results, it was concluded that the polymer blends without the addition of filler have lower strength at break than the pure component. In PLA-N blends, TiO2 has been shown, as a better filler, while in PLA-S blends silica was a better choice. Morphology studies showed that particle size distribution and phase dispersion have the greatest influence on the mechanical properties of the blends.

Cilj ovog istraživanja bio je ispitati svojstva polimernih mješavina akrilonitril-butadien-stirena i polietilena niske gustoće (ABS/PE-LD) i akrilonitril-butadien-stirena i polietilena visoke gustoće (ABS/PE-HD) kao i svojstva čistih komponenata, tj. čistog akrilonitril-butadien-stirena (ABS), polietilena niske gustoće (PE-LD) i polietilena visoke gustoće (PE-HD). Uzorci su pripremljeni ekstruzijom. Ispitana su njihova mehanička i toplinska svojstva, te morfologija uzoraka. Na temelju dobivenih rezultata zaključeno je da je smjesa ABS/PE-LD 95/5 najbolja od ispitivanih po pitanju mehaničkih svojstava. The aim of this study was to examine the properties of polymeric mixtures of acrylonitrile-butadiene-styrene and low density polyethylene (ABS / PE-LD) and acrylonitrile-butadiene-styrene and high density polyethylene (ABS / PE-HD) as well as the properties of pure components, i.e. pure acrylonitrile-butadiene-styrene (ABS), low density polyethylene (PE-LD) and high density polyethylene (HDPE). Samples were prepared by extrusion. Their mechanical and thermal properties, as well as the morphology of the samples were examined. Based on the obtained results, it was concluded that the ABS / PE-LD 95/5 mixture was the best in terms of it's mechanical properties.

Cilj ovog istraživanja bio je ispitati utjecaj titanijevog dioksida kao nanopunila na svojstva polimernih mješavina PLA/PE-LD 90/10 i PLA/PE-HD 90/10, kao i na svojstva čistih komponenata, tj. čistog polilaktida (PLA), polietilena niske gustoće (PE-LD) i polietilena visoke gustoće (PE-HD). Korištena su tri nanopunila komercijalnih naziva P25 (praškasti TiO2), P25/20 (granulirani TiO2) i PC500 (praškasti TiO2). Uzorci su pripremljeni ekstruzijom te su određena njihova mehanička i toplinska svojstva, ispitana je morfologija uzoraka te su snimljeni FTIR spektri čistih komponenata. Na temelju dobivenih rezultata zaključeno je da punila povoljno utječu na sva mehanička svojstva jedino u slučaju polimerne mješavine PLA/PE-LD 90/10. Punila su poboljšala neka mehanička svojstva čiste komponente PE-LD, dok kod ostalih sustava dodatak nanopunila uzrokuje lošije mehaničko ponašanje u odnosu na nepunjene sustave. Od pripremljenih nanokompozita, najbolja svojstva je u većini slučajeva pokazao onaj koji je pripremljen dodatkom nanopunila P25. The aim of this study was to investigate the influence of titanium dioxide as a nanofiller on the properties of PLA/PE-LD 90/10 and PLA/PE-HD 90/10 polymer blends, as well as on the properties of pure polylactide (PLA), polyethylene low density (PE-LD) and polyethylene high density (PE-HD) components. Three different nanofillers were used – P25 (TiO2 powder), P25/20 (granulated TiO2) and PC500 (TiO2 powder). Samples were prepared by extrusion and their mechanical and thermal properties were investigated, as well as the morphology of the samples. Also, FTIR spectrum of PLA, PE-LD and PE-HD was recorded. Based on the results, it was concluded that fillers can improve mechanical properties of the PLA/PE-LD 90/10 blend. Fillers can also have beneficial effect on some mechanical properties of the pure PE-LD component. As for the rest of the composites, it was observed that the addition of nanofillers causes poorer mechanical behavior compared to unfilled blends and pure components. In most cases, the best properties showed nanocomposites prepared by addition of the P25 filler.

Cilj ovog rada bio je istražiti utjecaj različitih udjela polietilena (PE) na toplinska i mehanička svojstva, te morfologiju polimernih mješavina na osnovi polilaktida (PLA). Svrha miješanja PE s PLA bila je dobivanje biorazgradive polimerne mješavine sa što manjim udjelom petrokemijske sintetske komponente te sniženje cijene krajnjeg polimernog proizvoda. Kao druga komponenta u mješavinama na osnovi PLA korišteni su polietileni različitih gustoća, polietilen niske gustoće i visoke gustoće. Nadalje, s aspekta primjene polimernog proizvoda cilj je bio prevladati nedostatke PLA, kao što su visoki modul i krutost, uz zadržavanje dobrih svojstava izvorno visoke čvrstoće PLA, kako bi dobili čvrst, ali i elastičan te fleksibilan materijal. Zbog nemješljivosti komponenata nužno je dodavanje punila čija je svrha modifikacija međupovršine što omogućuje bolje povezivanje polimera i bolja mehanička svojstva. Kako bismo proučili djelovanje punila na sustav PLA/PE-LD i PLA/PE-HD, odabranim mješavinama dodano je nanopunilo CaCO3 (5 masenih %) te su ispitana svojstva pripremljenih nanokompozita. Karakterizacija čistih komponenata, mješavina i kompozita provedena je rasteznim ispitivanjem, ispitivanjem udarne žilavosti, razlikovnom pretražnom kalorimetrijom (DSC) i pretražnom elektronskom mikroskopijom (SEM). Dodatkom druge komponente, PE, dolazi do očekivanog smanjenja inicijalno visoke prekidne čvrstoće čistog PLA i do smanjenja modula i krutosti, dok se istezljivost povećava tek kod većih udjela PE u mješavinama. Najlošija svojstva kod oba sustava, s PE-LD i PE-HD, primjećuju se kod mješavina s istim udjelima oba polimera, PLA i PE. Nanopunilo je dodano mješavinama s malim udjelom polietilenske komponente. Nanopunilo se ne smješta na međupovršinu između nemješljivih polimera, ali utječe na poboljšanje svojstava sustava PLA/PE-LD. Utječe na poboljšanje čvrstoće i žilavosti, a povećava i kristalnost sustava PLA/PE-LD kojem se dodaje, dok na sustav PLA/PE-HD ne utječe značajnije. The aim of this study was to research the influence of polyethylene (PE), which is added in various amounts, on the thermal and mechanical properties, also, morphology of polymer blends based on polylactide (PLA). The purpose of blending PE with PLA was to produce a biodegradable polymer blends with a small amount of petroleum – based synthetic component and to reduce the price of final polymer product. As the second component in the PLA – based blends, polyethylenes of various densities were used, such as low density and high density polyethylene. Furthermore, from the point of application of the final polymeric product, the aim was to overcome the disadvantages of PLA, such as high modulus and stiffness, while maintaining good properties of PLA, such as high strength, to obtain firm, but elastic and flexible material. Due to the immiscibility of the components, it is necessary to add filler with the purpose to modify the interface between polymers which would provide better adhesion and mechanical properties of the material. In order to study the effect of filler on the PLA/LDPE and PLA/HDPE systems CaCO3 nanofiller (5wt. %) was added to the selected blends, and the properties of nanocomposites were tested. Pure components, blends and composites were characterized by tensile test and impact resistance examination, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). When the second component is added, it reduces the initial high strength at break of pure PLA and, also, module and stiffness, while the elasticity increases only with larger amounts of PE in blends. The worst properties for both systems, with LDPE and HDPE, are noticed for the mixtures with the same amounts of both polymers. Nanofiller was added to the mixtures with small amount of PE component. Nanofiller is not situated at the interface, but it still affects the properties of PLA/LDPE blends. Nanofiller improves strength and toughness; also it increases crystallinity of PLA/LDPE systems, but has no effect on mechanical properties of PLA/HDPE blends.

U ovom radu prvo su karakterizirane višestijene ugljikove nanocjevčice (MWCNT) te MWCNT modificiranih –COOH skupinama. Karakterizacija MWCNT, MWCNT-COOH provedena je Ramanovom spektroskopijom, termogravimetrijskom analizom, zatim pomoću pretražne elektronske mikroskopije, mjerenjem kontaktnog kuta, te određivanjem disperzivnosti u različitim otapalima. Zatim je istraživan učinak dodatka MWCNT te MWCNT–COOH u rasponu udjela od 0-4% mas. na svojstva poliuretana. Uzorci nanokompozita pripravljani su postupkom iz otopine poliuretana u acetonu te polaganim sušenjem otopina na sobnoj temperaturi. Učinak dodatka nanopunila na sferolitnu strukturu poliuretana te raspodjeljenost nanopunila u PU matrici anlizirana je optičkom polarizacijskom mikroskopijom. Toplinska svojstva u neizotermnim i izotermnim uvjetima istraživana su diferencijalnom pretražnom kalorimetrijom (DSC), a toplinska stabilnost termogravimetrijskom analizom (TGA). Električna provodnost uzoraka određivana je metodom četiri kontakta. Utjecaj dodatka punila na mehanička svojstva PU kompozita ispitana je testom jednoosnog istezanja. Ramanova spektroskopija pokazala je da MWCNT imaju veći udio nečistoća nego MWCNT-COOH. TGA analiza pokazala je da su MWCNT-COOH toplinski stabilnije od MWCNT. Rezultati SEM analize pokazali su da funkcionalizacija ne utječe na stupanj agregacije. Rezultati kontaktni kuteva ukazuju da se funkcionalizacijom s -COOH skupinom uvelike mijenja polarnost nanocijevčica. Rezultati određivanja disperzivnosti pokazali su da su obe vrste nanocjevčica jako dobro dispergirane u acetonu. Optička polarizacijska mikroskopija pokazala je da dodatak oba punila razrušava krupnu sferolitnu morfologiju poliuretana. Uočeno je da su na makrorazini modificirane MWCNT-COOH bolje dispergirane u masi uzorka nego čiste MWCNT. DSC rezultati pokazali su da u neizotermnim uvjetima do određenog udjela dodatak obje vrste MWCNT ubrzavaju kristalizaciju mekog segmenta poliuretana. U uvjetima izotermne kristalizacije MWCNT također znatnije ubrzavaju kristalizaciju nego MWCNT-COOH. Rezultati termogravimetrijske analize upućuju da se dodatkom obje vrste MWCNT znatno poboljšava toplinska stabilnost u čitavom rasponu udjela nanopunila. Rezultati vodljivosti pokazali su da se i dodatakom malih udjela MWCNT vodljivost znatno povećava. Rezultati ispitivanja mehanički svojstava nanokompozita ukazuju da dodatak obje vrste MWCNT punila snižava prekidnu čvrstoću i prekidno istezanje kompozita. In this study carbon nanotubes (MWCNTs) and MWCNTs modified with COOH groups were characterized. Characterization of MWCNTs, MWCNTs-COOH was performed by Raman spectroscopy, thermal analysis, then using scanning electron microscopy, by measuring the contact angle, and determining dispersibility in various solvents. After that the effect of the addition of MWCNTs and MWCNTs-COOH in range of 0-4% wt. on the properties of polyurethane were investigated. Samples of nanocomposite were prepared from solution of polyurethane in acetone and slowly drying the solution at room temperature. The effect of the addition of nanofiller on spherulite structure of polyurethane and distribution nanofiller in PU matrix were analyzed by optical polarization microscopy. Thermal properties in the non-isothermal and isothermal conditions were investigated by differential scanning calorimetry (DSC) and thermal stability by thermogravimetric analysis (TGA). The electrical conductivity of the samples was determined using four probe method. Effect of the addition of fillers on the mechanical properties of PU nanocomposites was examined by uniaxial deformation test. Raman spectroscopy showed that MWCNTs have a higher proportion of impurities than MWCNTs-COOH. TGA analysis showed that MWCNTs-COOH are more thermally stable than MWCNTs. The results of SEM analysis showed that the functionalization does not affect the degree of aggregation. The results of the contact angles indicate that the functionalization by COOH groups significantly changes the polarity of the nanotubes. The results of determining dispersibility showed that both types of nanotubes are very well dispersed in the acetone. Optical polarization microscopy showed that the addition of both nanofillers disrupts the spherulite morphology of polyurethane. It was noted that at the macro level modified MWCNTs-COOH are better distributed in the the sample than pure MWCNTs. DSC results showed that in the non-isothermal conditions up to the addition of a certain amount of both types of MWCNTs accelerate the crystallization of the soft segments of polyurethane. In terms of isothermal crystallization MWCNTs also significantly accelerate crystallization than MWCNTs-COOH. The results of thermogravimetric analysis indicate that the addition of both types of MWCNTs significantly improves the thermal stability. Conductivity results showed that the the addition of small amount of MWCNTs significantly increases the conductivity. The results of the mechanical properties of the nanocomposite show that addition of both types of fillers MWCNTs reduced tensile strength and elongation of the composite.

Novi trendovi u istraživanjima su pronalazak materijala koji bi konkurirali na tržištu svojim dobrim svojstvima, biodegradabilnosti i proizvodnji iz obnovljivih izvora energije. Polilaktid je jedan od takvih materijala, koji s dodatkom ugljikovih nanocjevčica može konkurirati na tržištu. U ovom radu provedena su istraživanja utjecaja dodatka različitih masenih udjela funkcionaliziranih ugljikovih nanocjevčica (MWCNT-COOH; MWCNT-COOC12H25) u polilaktid. Uzorci su zamiješani na Brabender gnjetilici postupkom u talini. Potom je ispitivana morfologija, mehanička svojstva i mehanizam loma pomoću mehaničke kidalice i pretražnog elektronskog mikroskopa. Toplinska svojstva ispitivana su metodom diferencijalne pretražne kalorimetrije, te toplinska stabilnost termogravimetrijskom analizom. Električna svojstva određivana su mjerenjem otpora metodom četiri probe. Rezultati su pokazali da se mehanička svojstva PLA sustava s MWCNT-COOH i MWCNT-COOC12H25 nanopunilima poboljšavaju najznačajnije do 2 % mas. PLA nanokompoziti (do 2 % mas.) s ugljikovim nanocjevčicama funkcionaliziranim dugim alkilnim lancima (MWCNT-COOC12H25) imaju nešto bolja svojstva od sustava s MWCNT-COOH zbog bolje raspodijeljenosti MWCNT-COOC12H25 punila, što je potvrđeno analizom površine kidanja. Rezultati DSC analize pokazali su da dodatak oba punila ubrzava neizotermnu kristalizaciju PLA matrice i to najznačajnije do 2 % mas. Dodatak MWCNT-COOC12H25 punila zbog dugog alkilnog lanca koji ulazi u matricu znatnije ometa slaganje polimernih lanaca u kristalne forme. Neovisno o vrsti funkcionalnih skupina graftiranih na površini MWCNT tijekom procesa hladne kristalizacije u PLA nanokompozitima stvara se veći udio slabije uređenih struktura nego u čistoj PLA matrici. Toplinska stabilnost najznatnije se poboljšava dodatkom do 2 % mas. punila. Ovakvi rezultati se pripisuju učinku barijere koju stvaraju ugljikove nanocjevčice i dobroj toplinskoj vodljivosti MWCNT. Nije vidljiva znatna razlika u poboljšanju toplinske stabilnosti ovisno o funkcionalnoj skupini graftiranoj na ugljikovu nanocjevčicu. Rezultati ispitivanja električne vodljivosti pokazuju značajno poboljšanje vodljivosti već dodatkom malih količina funkcionaliziranih MWCNT do 0,5 % mas. zbog nastajanja trodimenzionalne vodljive mreže u matrici te istraživani nanokompoziti imaju potencijalnu primjenu za elektrostatsko bojanje i odvođenje elektrostatskog naboja. New trends in research are finding materials who would compete in open market with it's properties, biodegradability and production from renewable sources of energy. Polylactide is one of those materials, and with addition of carbon nanotubes it can compete in the open market. In this study the addition of different quantities of modified carbon nanotubes (MWCNT-COOH; MWCNT-COOC12H25) in PLA was investigated. Samples were prepared by melt mixing in a Brabender plasticoder. Within this study morphology, mechanical properties and mechanism of failure with scanning electron microscopy (SEM) and universal mechanical testing machine were investigated. Thermal properties were investigated by differential scanning analysis and thermal stability was determined by thermogravimetric analysis. Electrical properties were investigated by measuring resistance using four probe method. Results showed the most significant increase of mechanical properties for PLA systems with MWCNT-COOH and MWCNT-COOC12H25 nanofillers up to 2 % wt. PLA nanocomposites (up to 2 % wt) with carbon nanotubes functionalized with long alkyl chains (PLA/MWCNT-COOC12H25) have slightly better properties than systems with MWCNT-COOH due to better distribution of MWCNT-COOC12H25 in PLA matrix, which is confirmed also by fracture surface analysis. DSC results indicate that addition of both fillers accelerates nonisothermal crystallization of PLA matrix and this effect is more pronounced up to 2 % wt. Addition of MWCNT-COOC12H25 nanofiller, due to long alkyl chains that entrance in a matrix, more significantly hinders ordering of polymer chains in the crystalline form. Regardless of the type of grafted functional groups on the surface of MWCNTs, during the cold crystallization a higher proportion of lower-ordered structures than in a pure PLA matrix were created. The most prominent improvement of thermal stability is obtained by the addition of 2% wt of fillers. These results can be attributed to formation of barrier that carbon nanotubes formed and to the very high thermal conductivity of MWCNTs. Depending on the type of functional groups on the carbon nanotubes difference in the improvement of the thermal stability were not observed. The results of electrical conductivity show significant improvement of conductivity with addition of small amounts of functionalized MWCNTs up to 0.5% wt due to the formation of three-dimensional conductive network in the PLA matrix. The investigated nanocomposites have potential use for electrostatic painting and dissipation of electrostatic charge.