Samenvatting
This research project focuses on the development of a new softening technology where regeneration of ’resin’ occurs by a change in temperature. In this project a new blockcopolymer of polystyrene (PS) and poly(di-ethyleneglycolacrylate) (PDEGA) is synthesized to form polymers with an hydrophobic and an hydrophilic block. In water these polymers form micelles with a PS core and a PDEGA tail. The PS core is provided with a positively charged group and the PDEGA tails with a negatively charged group. PDEGA has a lower critical solution temperature (LCST) which means that below this temperature the chains of PDEGA are stretched and above this temperature chains collapse as a result of a poorer solubility, which brings the negative charges close to the positively charged PS core and internal charge neutralization occurs. As a result, multivalent hardness ions can be bound to the micelle below the LCST and will be
released above the LCST (see Figure 1).
CryoTEM and DLS studies were performed to confirm that micelles were formed with a PS core with a radius of 15 nm and a PDEGA corona of 20 nm (see figure 2a for a cryoTEM picture). Figure 2b shows the optical transmittance of aqueous solutions of PS-b-PDEGA at various concentrations as a function of temperature. Clearly, the PS-b-PDEGA precipitated from solution at temperatures within a range 29-34°C, which mainly depends on the concentration.
Focus in the remainder of this project will be on the binding of calcium ions to the micellar surface and the thermoreversible release of those ions from the micellar surface.
Originele taal-2 | Engels |
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Titel | Netherlands Process Technology Symposium 2009 (NPS-9),26-28 October, Veldhoven |
Plaats van productie | Netherlands, Veldhoven |
Pagina's | 1-1 |
Status | Gepubliceerd - 2009 |