Ispitivanje polimernih ovojnica za kontrolirano otpuštanje aktivne tvari

master's thesis

• Title (english): Study of polymeric envelopes for controlled release of active component
• Author: Igor Lukanović
• Mentor: Elvira Vidović (mentor)
• Committee member: Elvira Vidović (predsjednik povjerenstva)
• Committee member: Mirela Leskovac (član povjerenstva)
• Committee member: Jozefina Katić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2019-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Mineralna gnojiva osiguravaju hranjive tvari usjevima i pospješuju njihov rast te istovremeno igraju važnu ulogu u reguliranju pH i plodnosti tla. No, nekontrolirana uporaba mineralnih gnojiva može dovesti do neželjenih efekata kod biljaka. Zbog toga, posljednjih desetljeća sve se više pridaje važnost proizvodnji i uporabi gnojiva sa sporim ili kontroliranim otpuštanjem aktivne tvari što predstavlja poboljšanje u gospodarenju hranjivim tvarima za biljke. Upotreba takvog gnojiva predstavlja povećan agronomski učinak, bolji prinos, poboljšanu kvalitetu i izgled usjeva te u konačnici uštedu radne snage. Asimilacija fosfora u biljkama je prilično niska, što predstavlja ozbiljan problem za rast usjeva, budući da fosfor ima najvažniju ulogu u korijenskom sustavu. Ovakav problem moguće je riješiti korištenjem gnojiva sa sporim ili kontroliranim otpuštanjem aktivne tvari koje se može pripremiti oblaganjem granula različitim polimernim materijalima koji smanjuju njihovu brzinu otapanja. Celulozni acetat (CA) se pokazao kao privlačan polimerni materijal za oblaganje gnojiva zbog svoje biorazgradljivosti, netoksičnosti i niske cijene. U ovom radu, komercijalno granulirano gnojivo NPK 15-15-15 (Petrokemija d.d.) obloženo je različitim sustavima polimera u rotacijskom bubnju. Debljina polimernog sloja analizirana je skenirajućom elektronskom mikroskopijom (SEM), dok je profil otpuštanja fosfora analiziran UV-Vis spektroskopijom. Ustanovljeno je da povećavanjem broja ciklusa oblaganja raste debljina polimernog filma. Najdeblji sloj polimernog filma, koji je iznosio oko 200 μm nakon 20 ciklusa oblaganja, dobiven je korištenjem sustava CA/PMMA 50/50. Također, povećavanjem debljine polimernog filma, produžuje se oslobađanje fosfora iz obloženih granula gnojiva, a najsporije otpuštanje pokazao je sustav CA/PLA 50/50, iz kojeg je za 120 minuta otpuštanja oslobođeno 36,9 %, dok je iz neobloženih granula u istom vremenu oslobođeno 98,4 % fosfora.

Abstract (english)

Mineral fertilizers provide nutrients to crops and promote their growth, and at the same time they play an important role in regulating the pH and fertility of soil. However, the uncontrolled use of mineral fertilizers can cause side effects in plants. Therefore, in recent decades, the importance of producing and using fertilizers with slow or controlled release has become widely recognized as an efficient way of the nutrient management in plants The use of such a fertilizer represents improved agrotechnical measures, better yield, improved appearance and quality of the crop , as well as savings in labor. Assimilation of phosphorus in plants is quite low, which presents a serious problem for crop growth, since phosphorus plays the most important role in the root system. This problem can be solved by use of slow or controlled release fertilizers which can be prepared by coating the granules with various polymeric materials that reduce their dissolution rate. Cellulose acetate (CA) has proven to be one of the most attractive polymeric materials for fertilizer coating due to its biodegradability, non-toxicity and low cost. In this work, commercial granular fertilizer NPK15-15-15 (Petrokemija Plc.) is coated with different mixtures of polymer in a rotary drum. The thickness of the polymer layer was analyzed by scanning electron microscopy (SEM), while the phosphorus release profile was analyzed by UV-Vis spectroscopy. It has been found that by increasing the number of coating cycle, the thickness of the polymer film increases. The thickest layer of polymer film, which was around 200 μm after 20 cycles of deposition, was obtained using the CA/PMMA 50/50 polymer mixture. Also, by increasing the thickness of the polymer film, the release of phosphorus from the coated fertilizer granules was prolonged, and the slowest release was notified in the CA /PLA 50/50 system, where 36.9 % phosphorus was released during 120 minutes, while the uncoated granules displayed 98.4 % phosphorus release during the same time.

• Keywords: mineralna gnojiva; gnojivo s kontrolianim otpuštanjem aktivne tvari; polimeri; celulozni acetat; fosfor
• Keywords (english): mineral fertilizers; controlled release fertilizer; polymers; cellulose acetate; phosphorus
• Language: croatian
• URN:NBN: urn:nbn:hr:149:666896
• Study programme: Title: Chemical Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-02-23 12:33:27