Sinteza poroznih materialov iz metakrilatov in vinilestrov

doktorska disertacija

Marko Turnšek (Avtor), Peter Krajnc (Mentor)

Povzetek

V okviru doktorske disertacije smo s polimerizacijo v masi proučevali vpliv pogojev na pripravo glicidil metakrilatnih poroznih polimernih nosilcev. Proučili smo vplive zamreževala etilenglikol dimetakrilata in različnih porogenih topil na morfologijo poroznih nosilcev. Nosilce smo funkcionalizirali z različnimi amini in tioli. Dobljene porozne monolite smo tudi naknadno zamrežili, da smo povečali specifično površino. Pripravili smo tudi emulzije z visokim deležem notranje faze; v organski fazi smo imeli raztopljen monomer. Kot monomer smo uporabili divinil adipat, ki je difunkcionalen vinil ester. Proučevali smo: vpliv sestave emulzije, tipa termičnega iniciatorja, dodatka topil in reakcijskih pogojev na stabilnost emulzije, morfologijo pripravljenih monolitov, obliko in velikost por ter poroznost. Divinil adipat kot samostojno uporabljen monomer še ni bil opisan, zato smo raziskali vpliv razmerja med hidrofilno in hidrofobno fazo emulzije na pripravo stabilne emulzije. Potreben je bil izbor primernih surfaktantov, kombinacije različnih surfaktantov ter količine topila. Pripravljene emulzije smo termično polimerizirali. Za radikalsko iniciacijo smo uporabili različne termične iniciatorje; prav tako smo testirali uporabo fotokemičnih iniciatorjev. Proučili smo vpliv segrevanja in staranja emulzije na njeno stabilnost ter na združevanje kapljic emulzije. S segrevanjem emulzije smo dosegli 5-kratno povečanje kapljic, s staranjem 25 ur pa 0,4-kratno povečanje. Pripravili smo tudi emulzije brez soli v vodni fazi in tako povzročili Ostwaldovo rast in koalescenco kapljic v emulziji. Na ta način smo povečali velikost kapljic za dvakrat. Pri vseh metodah smo spremljali velikost kapljic emulzije in velikost primarnih por monolita, saj je velikost por polimera običajno sorazmerna z velikostjo kapljic notranje faze emulzije. Pripravljene monolite smo izpostavili različnim medijem z različnimi koncentracijami ter tako ugotavljali primernost medija in hitrost biorazgradnje. Pripravili smo tudi porozne polimere iz emulzije z visokim deležem notranje faze, nasičene z aluminijevim oksidom. Kot monomere smo uporabili propoksiliran trimetilol propan triakrilat in metil metakrilat, zamrežen z etilenglikol dimetakrilatom. Raziskali smo vpliv sestave emulzije na morfologijo monolitov: vpliv topila, surfaktanta, disperzanta in količino vodne faze. Z elektronsko mikroskopijo smo preučevali morfologijo pripravljenih monolitov. Vzorce z ustrezno poliHIPE morfologijo smo postpolimerizacijsko obdelali. V cevni peči smo s počasnim intervalom segrevanja do 1400°C izžgali organske komponente monolita. Ostal je skelet iz aluminijevega oksida, ki smo ga okarakterizirali z adsorpcijo/desorpcijo dušika, živosrebrno porozimerijo, helijevo piknometrijo in elektronsko mikroskopijo. Ustvarili smo visoko porozen polimer iz aluminijevega oksida z značilno poliHIPE morfologijo. Ugotovili smo tudi, da se med segrevanjem morfologija bistveno ne spremeni.

Ključne besede

polimeri;polimerizacija v masi;metakrilati;vinil estri;emulzije;poliHIPE;funkcionalizacija polimerov;biorazgradnja;kompozitni materiali;porozna keramika;doktorske disertacije;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2014
Tipologija:	2.08 - Doktorska disertacija
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[M. Turnšek]
UDK:	66.095.26:544.773.3(043.2)
COBISS:	17944598
Št. ogledov:	1679
Št. prenosov:	286
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Synthesis of porous polymers from methacrylates and vinyl esters
Sekundarni povzetek:	Influences of reaction conditions on the structure of porous glycidyl methacrylate type polymer supports were studied. Glycidyl methacrylate was chosen as the main functional monomer due to availability and possibility of nucleophilic modifications of epoxy groups. We studied the influence of crosslinker ethylene glycol dimethacrylate and various porogenic solvents on the morphology of porous polymer supports. Porous polymer supports were subsequently functionalized with various amines and thiols. Furthermore, porous polymers were hypercrosslinked, with an aim of increasing specific surface area of polymers. Furthermore, high internal phase emulsions internal phase containing dissolved monomer were prepared. Divinyl adipate was chosen as monomer because it is a reactive difunctional vinyl ester that consists of two ester bonds which can undergo hydrolytic attack. Influences of different compositions of emulsions, different types of initiator, addition of solvents and reaction conditions on emulsion stability and morphology of prepared polymer supports were studied. Appropriate surfactants and solvent were chosen for the formations of stable emulsions. Thermal initiator was used for polymerisation of emulsions and the use of photochemical initiator was also studied. We also studied the size and the shape of droplets from emulsions being heated during the preparation and aging of emulsions. An increase in droplet size of 5 fold and with aging after 25 hours increase of 0.4 fold was achieved. Emulsion preparation without salt in aqueous phase which promotes Ostwald ripening and coalescence of emulsion droplets was further studied. Prepared divinyl adipate porous polymer supports were exposed to PBS buffer and sodium hydroxide with different concentrations for studying the rate of degradation and adequacy of these media for degradation. In the last part of the thesis work, emulsions with incorporated inorganic component namely aluminium oxide in the continuous phase, were prepared. Propoxylated trimethylolpropane triacrylate and methyl methacrylate were used as monomers. Influence of solvent, amount of water phase, surfactant and dispersing agent on emulsion stability and morphology were studied. Samples with open cellular structure were treated thermally after the polymerisation. At 1400° C the entire organic component was burned and only the inorganic component remained. The aluminium oxide, which was fused together by the high temperature formed a solid. These sintered materials obtained the initial morphology of the precursor polyHIPE.
Sekundarne ključne besede:	polymers;bulk polymerization;methacrylates;vinyl esters;emulsions;polyHIPE;biodegradation;composite materials;porous ceramics;
URN:	URN:SI:UM:
Vrsta dela (COBISS):	Doktorska disertacija
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	X, 127 str.
ID:	8724717