Poliakrilati kot funkcionalni porozni materiali: vpliv raft polimerizacije na morfologijo in mehanske lastnosti

Kovačič, Ana Katarina

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Title:	Poliakrilati kot funkcionalni porozni materiali: vpliv raft polimerizacije na morfologijo in mehanske lastnosti
Authors:	ID Kovačič, Ana Katarina (Author) ID Koler, Amadeja (Mentor) More about this mentor... ID Krajnc, Peter (Comentor)
Files:	MAG_Kovacic_Ana_Katarina_2026.pdf (6,12 MB) MD5: 6591237723A0E96BF2D07570466F53AE
Language:	Slovenian
Work type:	Master's thesis/paper
Typology:	2.09 - Master's Thesis
Organization:	FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:	V tem magistrskem delu smo sintetizirali 80 % porozne poli(etil akrilat-ko-trimetilolpropan triakrilat) (poli(EA-ko-TMPTA)) poliHIPE materiale z uporabo proste radikalske polimerizacije in reverzibilne adicijsko-fragmentacijske polimerizacije s prenosom verige (RAFT polimerizacije). Preučili smo vpliv vrste polimerizacije, deleža zamreževala (5, 10, 20 in 30 mol % TMPTA) ter množinskega razmerja iniciator (AIBN)/RAFT reagent (0,85; 1; 1,2 in 2,2) na morfologijo, specifično površino, mehanske lastnosti in kemijsko strukturo sintetiziranih poliHIPE materialov. Morfologijo vzorcev smo analizirali z vrstično elektronsko mikroskopijo (SEM). Rezultati so pokazali, da imajo vsi sintetizirani materiali značilno odprtocelično poliHIPE strukturo z medsebojno povezanimi porami, kar potrjuje uspešno sintezo poliHIPE materialov ne glede na izbran tip polimerizacije. Vendar pa so materiali, sintetizirani z RAFT polimerizacijo, izkazovali bolj homogeno morfologijo por in izrazitejšo odprtost por v primerjavi s poliHIPE materiali, pripravljenimi s prosto radikalsko polimerizacijo. Pri vzorcih pripravljenih s prosto radikalsko polimerizacijo se je z naraščanjem deleža zamreževala velikost por zmanjševala, medtem ko pri RAFT vzorcih tega nismo opazili. Ugotovili smo tudi, da tako delež zamreževala kot množinsko razmerje AIBN/RAFT reagent pomembno vplivata na velikost por, njihovo homogenost in razvoj povezovalnih por. Specifično površino materialov smo določili z merjenjem adsorpcije/desorpcije dušika po BET metodi. Vzorci, pripravljeni s prosto radikalsko polimerizacijo, so imeli BET specifične površine med 0,18 in 5,07 m²/g, medtem ko so materiali, sintetizirani z RAFT polimerizacijo, dosegli vrednosti do 11,35 m²/g. Povečanje specifične površine tekom RAFT polimerizacije je posledica formiranja večjega števila mezopor (velikosti med 2 in 5 nm). Največje specifične površine so bile dosežene pri vzorcih z 10 in 20 mol % zamreževala in pri množinskem razmerju AIBN/RAFT = 1. Preskusi tlačne trdnosti so pokazali, da RAFT polimerizacija bistveno izboljša mehanske lastnosti poliHIPE materialov. RAFT vzorci so dosegli tudi do štirikrat višje vrednosti maksimalne tlačne napetosti (do 3 MPa) in do petkrat višje vrednosti modula elastičnosti (do 27 MPa) kot primerljivi vzorci, pripravljeni s prosto radikalsko polimerizacijo. Izboljšane tlačne lastnosti pripisujemo nastanku bolj enakomerne in bolje nadzorovane tridimenzionalne polimerne mreže z bolj homogeno porazdelitvijo mest zamreženja, kar se kaže tudi v bolj homogeni porozni strukturi. FTIR analiza pa je potrdila uspešno polimerizacijo in nastanek poli(EA-ko-TMPTA) materialov. Na splošno se je RAFT polimerizacija izkazala kot učinkovit pristop za prilagajanje porozne arhitekture poli(EA-ko-TMPTA) poliHIPE materialov, saj omogoča sočasno izboljšanje morfologije, BET specifične površine in mehanskih lastnosti pri tlačni obremenitvi. Ti rezultati poudarjajo potencial RAFT pripravljenih poliHIPE materialov za uporabo v naprednih funkcionalnih poroznih materialih.
Keywords:	poliHIPE materiali, prosta radikalska polimerizacija, RAFT polimerizacija, RAFT zamreženje, porozni polimeri, mehanske lastnosti
Place of publishing:	Maribor
Year of publishing:	2026
PID:	20.500.12556/DKUM-100014
Publication date in DKUM:	17.09.2026
Views:	99
Downloads:	1
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Categories:	KTFMB - FKKT
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Licences

License:	CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

Link:	http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:	The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:	02.09.2026

Secondary language

Language:	English
Title:	Polyacrylates as functional porous materials: the influence of raft polymerisation on morphology and mechanical properties
Abstract:	In this master’s thesis, poly(ethyl acrylate-co-trimethylolpropane triacrylate) (poly(EA-co-TMPTA)) polyHIPE materials with 80% porosity were synthesized using free-radical polymerization and reversible addition–fragmentation chain-transfer (RAFT) polymerization. We investigated the influence of crosslinker content (5, 10, 20, and 30 mol % TMPTA) and molar ratios of initiator and RAFT agent (0.85, 1, 1.2, and 2.2) on morphological and mechanical properties and chemical composition of synthesized polymers. In addition, the effect of polymerization method on the properties of prepared materials was evaluated. Synthesized materials were characterized by scanning electron microscopy (SEM), FT-IR spectroscopy, and nitrogen adsorption-desorption measurements for determination of specific surface area and pore size distribution (BET/BJH). Morphology of polyHIPE materials was analyzed by scanning electron microscopy (SEM). Results revealed that all synthesized materials exhibited a characteristic open-cell polyHIPE structure with interconnected pores, confirming the successful synthesis of polyHIPE materials regardless of chosen polymerization technique. However, materials synthesized via RAFT polymerization exhibited more homogeneous morphology and open pore structure compared to polyHIPE materials synthesized by free-radical polymerization. For samples prepared by free-radical polymerization, pore size decreased with increasing crosslinker content, whereas no such reduction was observed for the RAFT samples. Furthermore, it was established that both the crosslinker content and AIBN/RAFT agent molar ratio significantly affects pore size, pore homogeneity, and development of open pore structure. Specific surface area of materials was determined by nitrogen adsorption-desorption measurements using BET method. Samples prepared by free-radical polymerization exhibited BET specific surface areas ranging from 0.18 to 5.07 m²/g, whereas materials synthesized by RAFT polymerization achieved values up to 11.35 m²/g. The increase in specific surface area during RAFT polymerization is attributed to the formation of a higher volume of mesopores (sizes between 2 and 5 nm). The highest specific surface areas were obtained for samples with 10 and 20 mol % crosslinker and at AIBN/RAFT molar ratio of 1. Compressive tests demonstrated that RAFT polymerization substantially enhances mechanical properties of polyHIPE materials. RAFT samples achieved up to four-fold higher maximum compressive stress (up to 3 MPa) and up to five-fold higher elastic modulus (up to 27 MPa) compared to equivalent samples prepared by free-radical polymerization. These improved compressive properties are attributed to the formation of a more uniform and better-controlled three-dimensional polymer network with more homogeneous distribution of crosslinking density, which is also reflected in more homogeneous porous structure. FT-IR analysis confirmed successful polymerization and formation of poly(EA-co-TMPTA) materials. Overall, RAFT polymerization proved to be an effective approach for tailoring porous architecture of poly(EA-co-TMPTA) polyHIPE materials, enabling simultaneous improvement of morphology, BET specific surface area, and compressive mechanical properties. These results highlight the potential of RAFT-derived polyHIPE materials for applications in advanced functional porous materials.
Keywords:	polyHIPE materials, free radical polymerisation, RAFT polymerisation, RAFT crosslinking, porous polymers, mechanical properties

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