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Synthesis on high solids coatings based on molecular brushes
Thesis (PhD)--Stellenbosch University, 2017.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2017
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| _version_ | 1867614115067854848 |
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| access_status_str | Open Access |
| author | Phiri, Mapoloko Mpho |
| author2 | Klumperman, Bert |
| author_browse | Klumperman, Bert Phiri, Mapoloko Mpho |
| author_facet | Klumperman, Bert Phiri, Mapoloko Mpho |
| author_sort | Phiri, Mapoloko Mpho |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2017. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/100904 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:46:54.487Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/100904 Synthesis on high solids coatings based on molecular brushes Phiri, Mapoloko Mpho Klumperman, Bert Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Molecular brushes High solid coatings β-scission UCTD Thesis (PhD)--Stellenbosch University, 2017. ENGLISH ABSTRACT: This dissertation describes the synthesis and investigation into the application of bottle molecular brushes (MBs) as solvent free liquid binders in high solids coatings. The MBs used in this study are based on the alternating copolymers of maleic anhydride (MAh) with a donor monomer, i.e. n-butyl vinyl ether (n-BVE). During the conventional radical copolymerization of n-BVE with MAh, the1H NMR spectra showed the development of a small peak between 6.30-6.40 ppm, which we tentatively assigned to backbiting followed by β-scission. A slight detour was taken to study the identity of said peak using both one-dimensional (1D) and twodimensional (2D) NMR techniques. Additionally, the effects of changing copolymerization conditions on the amount of backbiting and β-scission were studied, paying close attention to the resultant molecular weight. This study proved that the product of the side reaction was consistent with the alternating copolymer with a terminal MAh or maleic acid (MAcid) unit. A mechanism by which the side reaction occurs is also proposed. Pertaining to the liquid MB binder, the point of departure was to explore the limits of the liquid nature on the polyethylene glycol modified n-BVEMA copolymer. In this study, the backbone chain length was varied while keeping the chain length of the grafts (PEG12-NH2) constant. All the MBs synthesized were found to be liquid with the viscosity of the liquid MBs increasing with increase in backbone chain length, where all the liquid MBs showed Newtonian flow properties up to shear rate of 1000 s-1. In the second part of this study, the backbone length was fixed while PEG3, PEG7 PEG12 and PEG17 were grafted off the copolymers backbone. PEG3 afforded solid MBs while PEG12 proved to be the ideal side chain length for the following studies as it presented the lowest viscosity liquid MBs at room temperature. To attain oxidative crosslinking MB binders, an amine derivative of linoleic acid (Lin-NH2) was synthesised and used to facilitate oxidative drying of the MB binders. PEG12-NH2 and polydimethylsiloxane (PDMS-NH2, Mn=1000gmol-1) were, on the other hand, used to introduce the liquid properties to the binder. Preliminary results show that PEG12 MB binders are ideal candidates for application as liquid binder as they afforded liquid binders at moderate temperatures. These binders were also found to cure at 50C in the presence of the drier indicating that they underwent catalysed oxidative crosslinking. These PEG12 MB binders showed increase in viscosity as a function of increased Lin-NH2 composition in the MB binder, further demonstrating that the liquid nature of these MBs was due to incorporation of PEG12 grafts. AFRIKAANSE OPSOMMING: Hierdie studie beskryf die sintese en ondersoek instelling om bottel molekulêre borsels (MBs) te gebruik as oplosmiddel-vrye vloeistofbinders in hoë-solied bedek-lae. Die MBs wat in hierdie studie gebruik is, is gebaseer op afwisselende kopolimere van maleïenanhidried (MAh) met ‘n donor monomeer, bv. n-butielvinieleter (n-BVE). Gedurende die konventionele radikaal kopolimerisasie van n-BE met MAh, het die 1H KMR spektra ‘n ontwikkeling van ‘n klein piek tussen 6.30-6.40 ppm getoon, wat ons toegeskryf het aan terugbyting gevolg deur β-splitsing. Tyd is geneem om die identiteit van die bogenoemde piek te bestudeer deur eendimensionele (1D) en tweedimensionele KMR tegnieke, sowel as die effek van verandering kopolimerisasie kondisies op die hoeveelheid terugbyting en β-splitsing wat plaasvind, terwyl die gevolgelike molekulêre gewig ook goed bestudeer is. Hierdie studie bewys dat die produk van die byreaksie ooreenstem met die afwisselende kopolimeer met ‘n terminale MAh of maleïnsuur (MAcid) eenheid. ‘n Meganisme wat die byreaksie volg, word ook bekendgestel. Rakende die vloeistof MB binder, die beginpunt van die studie was om die limiete van die vloeistof-natuur van die poliëtileenglikol veranderde n-BVEMA kopolimeer te bestudeer. In hierdie studie was die hoofketting(‘ruggraat’)lengte afgewissel terwyl die kettinglengtes van die ente (PEG12-NH2) konstant gehou is. Al die MBs wat gesintetiseer was, was vloeistowwe met die viskositeit van die vloeistof MBs wat toeneem met toename in hoofkettinglengte en al die vloeistof MBs was onderhewig aan Newtonian-vloei eienskappe tot ‘n skeerkoers van 1000 s-1. In die tweede gedeelte van hierdie studie, was die hoofkettinglengte konstant gehou, terwyl PEG3, PEG7, PEG12 en PEG17 as ente van die kopolimere se hoofketting afgegroei is. PEG3 het vastestof MBs produseer, terwyl PEG12 bewys is om die ideale sykettinglengte te wees vir die volgende studies, aangesien dit die laagste viskositeit MBs produseer. Om oksidatiewe kruisverbinding MB binders te bekom, is ‘n amien-afgeleide van linoleïensuur gesintetiseer en gebruik om oksidatiewe droging van die MB binders te fasiliteer. PEG12 en polidimetielsiloksaan (PDMS, Mn = 1000 gmol-1) was aan die ander hand gebruik om vloeistof eienskappe and die binder te skenk. Voorlopige resultate dui daarop dat PEG12MB binders die ideale kandidate is vir toepassing as vloeistofbinder, aangesien dit vloeistofbinders produseer by matige temperature. Hierdie binders het ook gekuur by 50 °C in die teenwoordigheid van die droër, wat dui daarop dat dit gekatiliseerde oksidatiewe kruisverbinding ondergaan het. Die PEG12MB binders het ‘n toename in viskositeit getoon as ‘n funksie van toenemende Lin-NH2 komposisie in die MB binder, wat verder bevestig het dat die vloeistof-natuur van hierdie MBs toegeskryf kan word aan die inkorporasie van die PEG12 ente. Doctoral 2017-02-10T07:27:51Z 2017-03-29T11:44:35Z 2017-02-10T07:27:51Z 2017-03-29T11:44:35Z 2017-03 Thesis http://hdl.handle.net/10019.1/100904 en_ZA Stellenbosch University 106 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Molecular brushes High solid coatings β-scission UCTD Phiri, Mapoloko Mpho Synthesis on high solids coatings based on molecular brushes |
| title | Synthesis on high solids coatings based on molecular brushes |
| title_full | Synthesis on high solids coatings based on molecular brushes |
| title_fullStr | Synthesis on high solids coatings based on molecular brushes |
| title_full_unstemmed | Synthesis on high solids coatings based on molecular brushes |
| title_short | Synthesis on high solids coatings based on molecular brushes |
| title_sort | synthesis on high solids coatings based on molecular brushes |
| topic | Molecular brushes High solid coatings β-scission UCTD |
| url | http://hdl.handle.net/10019.1/100904 |
| work_keys_str_mv | AT phirimapolokompho synthesisonhighsolidscoatingsbasedonmolecularbrushes |