Synthesis of benzyl methacrylate-based polymer additives to improve the low-temperature properties of diesel and biodiesel blends

U ovom radu provedena je sinteza 45 polimernih aditiva na osnovi metil ili benzil metakrilata uz oktadecil, dodecil te 2-(tert-butilamino) etil metakrilat. Cilj rada bio je istražiti utjecaj različitih omjera navedenih monomera na sniženje tecišta dizelskog goriva bez drugih aditiva, smjese dizela i 10 vol. % biodizela te čistog biodizela. Polimeri su sintetizirani radikalskom polimerizacijom u otopini toluena uz 50 mas. % monomera uz Peroxan PO 70 kao inicijator. Sintetiziranim polimerima provjerila se čistoća (uspješnost uklanjanja zaostalih monomera) metodom infracrvene spektroskopije s Fourierovom transformacijom. Metodom 1H nuklearne magnetske rezonancije potvrđena je struktura polimernim aditivima. Toplinska svojstva ispitala su se metodom diferencijalne pretražne kalorimetrije. Formulacijama polimernih aditiva udjela 2000 ppm po masi u dizelu, smjesi B10 i B100 ispitana su niskotemperaturna svojstva radi utvrđivanja utjecaja različitih omjera komonomera u polimeru. Metodom diferencijalne pretražne kalorimetrije ispitan je utjecaj polimernih aditiva na temperaturu kristalizacije aditiviranih goriva te na promjenu entalpije kristalizacije. Kako bi se utvrdio utjecaj polimernih aditiva na temperaturu tecišta formulacija goriva, provedeno je mjerenje temperatura tecišta smjesa automatskom metodom po ASTM D5950. Naposlijetku se promatrao utjecaj aditiva na morfologiju i veličinu kristala n-parafina pomoću mikroskopa s polarizacijom dok se smjesa hladila postoljem s hlađenjem. Radom je utvrđeno da se najveće sniženje temperature tecišta postiže polimernim aditivima s najvećim udjelom dodecil metakrilata i najmanjim udjelom metil i benzil metakrilata. Ovi polimeri snizili su temperaturu tecišta s -18 °C neaditiviranog dizelskog goriva na -45 °C. Isti polimerni aditivi pokazali su najveće sniženje tecišta i u formulaciji B10 goriva gdje je tecište sniženo s -18 °C na -48 °C. Pripremljena je i smjesa funkcionalnog polimernog aditiva masenog udjela 2000 ppm u B100 gorivu te je toj formulaciji ispitano tecište. Toj formulaciji tecište se smanjilo s -6 °C (čisto B100 gorivo) na -12 °C. U radu nije utvrđen značajan utjecaj na tecište dizelskog goriva aditiviranim polimerom s komonomerom s aminskim članom. Utjecaj aminske skupine TBAEMA vidljiv je u promjeni morfologije kristala n-parafina u vidu smanjenja veličine kristala što može doprinijeti snižavanju temperature filtrabilnosti. In this work, the synthesis of 45 polymer additives based on methyl or benzyl methacrylate with octadecyl, dodecyl and 2-(tert-butylamino) ethyl methacrylate was carried out. The aim of the work was to investigate the influence of different proportions of the above monomers on the lowering of the pour point temperature of diesel fuel without additives, mixture of diesel and biodiesel (FAME) B10 and pure biodiesel B100. The polymers were synthesized in a toluene solution containing 50 mass percent of the monomer and with Peroxan PO 70 as initiator at 96 °C. The synthesized polymers were checked for purity (from residual monomers) by infrared spectroscopy with Fourier transformation. Thermal properties were tested by differential scanning calorimetry. Polymer additive mixtures of 2000 ppm mass in diesel, B10 and B100 were prepared to determine the influence of different comonomer contents in the polymer on the lowtemperature properties. Differential scanning calorimetry was used to investigate the influence of polymer additives on the crystallization temperature of the fuel formulations and on the enthalpy of crystallization. To determine the influence of polymer additives on the pour point temperature of fuel formulations, the pour point temperature of the mixtures was measured using the ASTM D5950 automated method. Finally, the effect of additives on the morphology and size of n-paraffin crystals was observed using a microscope with polarization while the mixture was cooled with a cooling stage. It was found that the greatest decrease in the pour point was achieved by the polymers with the highest proportion of dodecyl methacrylate and the lowest proportion of methyl and benzyl methacrylate. These polymers were able to lower the pour point from -18 °C in nonadditivated diesel fuel to -45 °C. These polymer additives showed the best effect in lowering the pour point in the formulation of B10 fuel, where the pour point was lowered from -18 °C to -48 °C. The formulations of the polymer additive in B100 fuel showed a decrease in pour point from -6 °C to -12 °C. The influence of the amine group TBAEMA can be seen in the change in the morphology of the n-paraffin crystals in the form of a decrease in crystal size, which may contribute to the lowering of the cold filter plugging point. In this work, no significant influence on the pour point of diesel fuel by the additive polymer with a comonomer containing an amine group was found.