Investigation of the copolymerization of butyl acrylate (BA) with vinyl neononanoate (VeoVA-9)

Hadasha, Waled (2006-12)

Thesis (MSc) -- University of Stellenbosch, 2006.

Thesis

ENGLISH ABSTRACT: This study has the goal of illuminating structure-properties relationships for copolymers of vinyl neononanoate (VeoVa-9) and butyl acrylate (BA). The VeoVa-9/BA copolymers were prepared using solution free radical copolymerization and miniemulsion copolymerization. The free radical copolymerization of VeoVa-9/BA at different feed ratios in benzene at 80°C using 2,2'azobis (2-methylpropionitrile) (AIBN) as initiator was investigated. The tenninal model was used to describe the copolymerization of these monomers and the copolymer composition was detem1ined using I H NMR spectroscopy. The reactivity ratios, estimated using the nonlinear least square method, and the 95% confidence interval giving values of the reactivity ratios, which were 0.042 (±0.014) and 6.95 (-0.53 /+0.65) for the VeoVa-9 and BA respectively. The copolymerization kinetics for the VeoVa-9/BA was investigated by following individual monomer consumption rates by in-situ NMR. The use of this method provides useful information about the individual monomer concentration during the course of reaction. The copolymerization reaction shows a higher tendency for BA to react than the VeoVa-9. The copolymerization of these monomers was also investigated in a heterogeneous system using the miniemulsion technique. In these investigations the effect of surfactant, initiator type and water solubility of the monomer on the batch and semi-batch miniemulsion behaviour was demonstrated. The rate of the miniemulsion polymerization increased with increasing surfactant concentration, while the final particle size of the latex decreased with increasing surfactant concentration in the miniemulsion mixture. Two types of initiators were used, water and oil-soluble initiators (ammonium persulphate (APS) and AIBN respectively). The rate of the batch miniemulsion polymerization showed dependency on the type of initiator used as the monomer conversion increased faster with APS than when using AIBN. The average final particle size was also larger when the AIBN was used than it was when the APS was used. The batch miniemulsion showed an increase in the nucleation (inhibition) period and a slower polymerization rate as the VeoVa-9 concentration increased. The increase in the VeoVa-9 concentration in both batch and semi-batch miniemulsions also led to an increase in the particle size. The obtained copolymers were characterized in terms of their chemical composition via two-dimensional chromatography (2-D), and in tern1s of some of their physical properties using dynamic mechanical analysis (DMA) and contact angle measurement. The 2-D analysis showed that all the BA was incorporated in the copolymer; this result was also confinned by IH NMR. The 2-D analysis also showed that the copolymer composition depends on the monomer addition mode in the semi-batch process. The copolymer glass transition temperature (Tg) value showed an increase as the VeoVa-9 concentration increased and the Tg values of the copolymers ranged between the two homopolymers' Tg values. The hydrophobicity of the copolymers increased as the VeoVa-9 concentration increased as was indicated by contact angle measurements.

AFRIKAANSE OPSOMMING:Die doel van die studie is om die struktuur-eienskap verhoudings vir kopolimere van vinielneononanoaat (YeoYa-9) en butielakrilaat (BA) te bestudeer. Die YeoYa-9/BA kopolimere was gesintetiseer deur van oplossingsvryeradikaalkopolimerisasie en miniemulsie kopolimerisasie gebruik te maak. Die vryeradikaalkopolimerisasie van Yeo Ya-9/BA met verkillende verhoudings YeoYa-9 tot BA in benseen, by 80°C, en met 2,2'azobis (2-metielpropionitriel) (AIBN) as afsetter, was ondersoek. Die reaktiwiteitsverhoudings van die monomere was skattings wat gemaak is deur van die terminale (endgroep)-model gebruik te maak. Die kopolimeersamestellings was bepaal deur van IH-KMR-spektroskopie gebruik te maak. Die reaktiwiteitsverhoudings, bepaal deur van die nie-lineere minste vierkantsmetode, asook om van die 95% sekerheidsinterval gebruik te maak, was 0.042 (±0.014) en 6.95 (-0.53 /+0.65) vir Yeo Ya-9 en BA onderskeidelik. Die kopolimerisasiekinetika vir verskillende YeoYa-9/BA verhoudings was ondersoek deur die individuele tempos van monomeeropname d.m.v. in-situ KMR te volg. Hierdie metode verskaf nuttige inligting oor die konsentrasies van individuele monomere gedurende die verloop van die reaksie. Die kopolimerisasiereaksie dui op 'n hoer waarskynlikheid vir BA om te reageer as die YeoYa-9. Die kopolimerisasie van hierdie monomere was ook ondersoek deur van 'n heterogene sisteem gebruik te maak, in samewerking met die mini-emulsie tegniek. In hierdie ondersoeke is die effek van die seep-tipe, inisieerder-tipe en die wateroplosbaarheid van die monomeer op die lot- en op die semi-lot-mini-emulsie gedrag gedemonstreer. Die tempo van die mini-emulsiepolimerisasie neem toe met toenemende seepkonsentrasie, terwyl die finale partikelgrootte van die lateks dan afneem. Die twee tipes initieerders wat gebruik was, was water- en olie-oplosbare initieerders (ammonium persulfaat (APS) en AIBN, onderskeidelik). Die tempo van die lot mini-emulsiepolimerisasie het op die afhanklikheid van die tipe initieerder gedui. Die monomeeromskakelingstempo was hoer wanneer APS gebruik was. Die gemiddelde finale partikelgrootte was groter wanneer AIBN gebruik was. Die lot-miniemulsiepolmerisasie het 'n toename in die inhibisie (inhibition/'nucleation')-periode getoon en 'n stadiger polimerisasieternpo soos wat die YeoYa-9 konsentrasie toegeneem het. 'n Toename in YeoYa-9 se konsentrasie het ook 'n groter partikelgrootte tot gevolg gehad. Die gesintetiseerde kopolimere is gekarakteriseer in terme van hul chemiese samestelling deur twee-dirnensionele chromatografie (2-D), en in terme van sekere fisiese eienskappe, deur van dinamiese rneganiese analise (DMA) en kontakhoekmetings gebruik te rnaak. Die 2-D analises het gewys dat al die BA geinkorporeer was in die kopolirneer. Hierdie resultaat was bevestig met 'H-KMR. Die 2-D analise het ook gewys dat die kopolirneersamestelling afhanklik is van die addissiewyse in die semi-lot proses. Die kopolirneer se glasoorgangstemperatuur (Tg) het toegeneern soos wat die konsentrasie van VeoVa-9 toegeneern het. Die Tg waardes van die kopolimere het gewissel tussen die van die twee hornopolimere se Tg waardes. Die hidrofobisiteit van die kopolirnere het toegeneern narnate die VeoVa-9 konsentrasie toegeneem het, soos ook aangedui deur kontakhoekmetings.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/50615
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