Carboxylated polystyrene

Catalysts with higher cryptand unit contents (up to 20% ring substitution) could be obtained by the condensation of carboxylated polystyrenes with aminoalkyl substituted cryptands, catalysts 15, (28). ... 

Transport of carboxylated polystyrene nanospheres (20 nm) across the BBB was studied in vivo following cerebral ischemia and reperfusion [100], A microdialysis probe was... 

Investigations of the electrophoretic behaviour of monodispersed carboxylated polystyrene latex dispersions as a function of particle size and electrolyte concentration by Shaw and Ottewill191 have confirmed, at least qualitatively, the existence of tea and relaxation effects. 

Experimental data are generally not in accord with the theoretical prediction in equation (8.21) regarding particle size96,196,204. For example, Ottewill and Shaw204 found no systematic variation in d log W/d log c for a number of monodispersed carboxylated polystyrene latex dispersions with the particle radius ranging from 30 nm to 200 nm. This problem still remains unresolved. 

Nanospheres are hollow nanosized particles (Figure 47.1C) that can be prepared by microemulsion polymerization or covering the surfaces of colloidal templates with thin layers of the desired material followed by selective removal of the templates (Hyuk Im et al., 2005). The carboxylated polystyrene nanospheres (20 nm) were evaluated for drug delivery... 

Figure 5 Fluorescent image of 200-nm carboxylated polystyrene microspheres in CF mucus collected by expectoration from an 18-year-old Caucasian male. Mucus fibers are bundled together, forming a thick mucus cord, which can be visualized owing, in part, to the adhesion of fluorescent microspheres.

The routes to sulfonated and carboxylated polystyrenes are illustrated in Figure 1. The specific experimental approaches are provided in the following sections. 

O-Qkcoci From carboxylated polystyrene by treatment with SOCK. Scavengen to separate secondary amines from tertiary amines. ... 

In our study, a carboxylated polystyrene microbead (Polybead Carboxyl-ate Microsphere, r = 5 /um, Polyscience, Inc., Warrington, PA) was used. 

Fig. 9.1. Plots of the UCFT as a function of the relative weight of poly(oxyethylene) steric stabilizer for three different latex particles 1, polyfvinyl acetate) 2, low carboxyl polystyrene 3, high carboxyl polystyrene latex particles. The dashed line is 0i. (after Dobbie et a ., 1973).

Fig. 9.2. Schematic representation of the multipoint anchoring of poly(oxyethylene) chains on high carboxyl polystyrene latex particles at low pH due to hydrogen bonding (inset).

As well as obtaining the ccc it is also useful to measure the electrophoretic mobility of the particles used as a function of concentration of the same electrolyte as used for the stability measurements. The electrophoretic mobility can then be converted into a -potential and a comparison made with the stability ratio measurements as shown in Figure 3.11. These measurements were made on a carboxylate polystyrene latex, with a number-average diameter of 423 nm [41]. The ccc for barium chloride solutions was found to be 1.41 x 10 mol dm and rapid coagulation commenced at a -potential of 17 mV. 

A rather specialized solid-state carbonation procedure can be used to carbonate PSLi and other living polymers with backbones which have glass transition temperatures significantly above room temperature. Thus, freeze-drying of benzene solutions of PSLi generates a porous solid which can be carbonated in the solid state to give minimal amounts of dimeric ketone products (1-2%). In addition, essentially quantitative yields of carboxylated polystyrene were obtained from freeze-dried solutions of PSLi that were complexed with 1-2 molar equivalents of TMEDA. No dimer was detected by SEC or TLC analyses. A freeze-dried sample of poly... 

Sulfonate vs Methacrylate vs Carboxylate. A comparison study (19) of the melt viscosity values of polystyrene ionomers, either randomly carboxylated or sulfonated in the para position of a benzene ring, showed that the melt viscosity values at 220°C of the two ionomers were significantly different. For example, at 2 mol% of ions, the melt viscosity of sodium sulfonated polystyrene ionomer was more than 2 orders of magnitude higher than that of the sodimn carboxylated polystyrene ionomer. 

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