Polystyrene-COOH

In order to synthesize polyfpropylene imine) dendrimers onto polystyrene via the divergent method, well-defined primary amine functionalized polystyrene had to be prepared as the core molecule. The anionic polymerization technique was chosen for the preparation of polystyrene (PS), because of the possibility of control over molecular weight and end group functionalization. An indirect amination procedure was developed [50], In this procedure a standard quantitative end-cap reaction with CO2 is used and a spacer is created between polystyrene and the primary amine function. The obtained polystyrene-COOH (PS-COOH), with Af around 3kgmol and values around 1.05, could be quantitatively reduced to the... 

The presence of a COOH functionality on a polystyrene resin can be detected using a 0.25% solution of malachite green-oxalate in ethanol in the presence of a drop of triethylamine. Beads with COOH functionalities are coloured dark green or appear as clear gel beads [Attardi, Porcu and Taddei Tetrahedron Lett 41 7391 2000]. 

Figure 7 The physico-mechanical properties of —CO—CH=CH—COOH groups polystyrenes (O, —) resistance to stretch, (cr) (A—) resistance to strike, (a) (A—) relative extention, (e) ( —) hardness (He) ( —-) adhesion, (A).

The lithio derivative of polystyrene offers a route to polystyrenes containing OH, COOH, B(OH)2, RSnCl2, and P2 groups by reaction with ethylene oxide, CO2, B(OR)3, MgBr2 followed by RSnCl3, and 2PCl, respectively. 

The first block (polybutadiene or polystyrene) is prepared by anionic polymerization, under high vacuum, in THF dilute solution (less than 5%), at low temperature (—70 °C) with cumylpotassium as initiator. Then, the living polymer is transformated into a hydroxylated polymer (PV—OH) by addition of ethylene oxide under vacuum, or into a carboxylated polymer (PV-COOH) by addition of carbon dioxide under vacuum. 

Fig. 1 Chemical formulas of the polymers used a carboxy-terminated polystyrene PS-COOH b random carboxy-terminated copolymer of polystyrene and 2,3,4,5,6-pentafluoropolystyrene FPS-COOH c 3-glycidoxypropyl trimethoxysilane (GPS) d tridecafluoro-1,1,2,2-tetrahydrooctyl) dimethylchlorosilane FSI...

Determining the amount of surface carboxyl groups as a function of the surfactant, it was shown that the dense monolayer of carboxylic groups (0.68nm2 per COOH 1.47 groups per nm2) on the particles prepared with nonionic surfactant was almost achieved with 3wt% of acrylic acid. More than 10 wt% of acrylic acid was required in the case of SDS-stabilized particles. TEM images of carboxyl-functionalized polystyrene particles stabilized with nonionic (Lutensol AT50) and ionic (SDS) surfactant are presented in Fig. 8. 

Later, synthetic exchange resins became important. They are of two kinds, cation exchangers and anion exchangers. The former are, as a rule, phenol formaldehyde or polystyrene resins in which there are extra — SO3H, —COOH or —OH groups. A portion of a typical structure is ... 

Fig. 2 A comparison of thermal FFF elution profiles for 0.2 jum particles of polystyrene (PS), carboxylated PS (PS/COOH), and aminated PS (PS/AB) in (a) an aqueous solution containing 9 mMNaN2 and 0.05 wt% FL-70 surfactant (pH 8.5) (b) 10 mM phosphate buffer (pH 4.7). Differences in retention are due to differences in thermodiffusion, which is governed by the surface composition of the particle.

Three homopolymer (diblock copolymer) phase boundary systems have been studied extensively the system of polystyrene (PS) and poly(2-vinylpyridine) (PVP) reinforced with diblock copolymers ofPS-PVP [22,25,28,31-33], the system of poly(methyl methacrylate) (PMMA) and PS reinforced with diblock copolymers of PMMA-PS [17,24,34,35] and the system of PMMA and poly(phe-nylene oxide) (PPO) reinforced by diblock copolymers of PMMA-PS [ 14,36,37]. Phase boundaries between PS and a crosslinked epoxy (XEp) were reinforced with carboxy-terminated PS chains whose -COOH ends reacted with either excess amines or epoxy to form a grafted brush at the interface [38,39]. In a similar manner, interfaces between rubber-modified PS (HIPS) and XEp reinforced with grafted PS-COOH chains have been investigated [40]. 

Polymer-supported reagent. A polymeric peracid reagent (1) has been prepared from a polystyrene resin cross-linked with 1 or 2% of divinylbenzene by chloromethylation and oxidation to give a resin substituted by carboxyl groups. The —COOH groups are then converted into —COOOH groups by treatment... 

In solution Fe(II)TPP reacts rapidly and irreversibly with oxygen to form a (i-oxo dimer (Equation 13). Fe(II) supported on silica gel does not dimerize (691. On lightly cross-linked polystyrenes dimerization occurs (681. but with 20-30% cross-linked DF 0.01, macroporous copolymers of styrene and 4 aminostyiene, dioxygen binds reversibly (107.1081. Similarly, Fe(in)Pc(COOH)4 bound covalently to linear polystyrene (1091 and to linear poty(styrene-co-2-vinylpyridine) (1101 is active for catalase-like decomposition of hydros peroxide. 

Cleavage of proteins at methionine with cyanogen bromide yields peptides that have homoserine at the COOH-terminus. Treatment of the peptide with anhydrous trifluoroacetic acid results in a lactone that is sufficiently activated to undergo aminolysis by aliphatic amines (Horn, 1975) or sequencing resins (Wachter et ai, 1975 Horn and Laursen, 1973 Bridgen, 1975) (Fig. 5). In this way, peptides are selectively attached at the COOH-terminus without the need for amino or carboxyl protection. Resins incorporating a )5-diamine structure, such as triethylenetetramine (TETA) polystyrene (Horn and Laursen, 1973) and j8-aminoethylaminopropylglass... 

Field emission scanning electron microscopy (FESEM) images of patterned polystyrene/ poly (acrylic acid) blends by patterned (a) 11-mercaptoundecanoic acid (MUDA) (-COOH)/ octadecanethiol (ODT) and (b) 11-hydroxy-l-undecanethiol (HUT) (-OH)/ODT. (Reprinted with permission from Wiley.)... 

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