Some problems in the physical and chemical characterization of functionalized supports

Functional Polymers from (Vinyl)polystyrene. Short Routes to Binding Functional Groups to Polystyrene Resin through a Dimethylene Spacer: Bromine, Sulfur, Phosphorus, Silicon, Hydrogen, Boron, and Oxygen

“…Preparation of PsCHCH 2 Precursor. Free-radical suspension copolymerization of divinylbenzene with other styrenic monomers gives cross-linked macroporous resins of porosities and surface areas controlled by relative proportions of water, monomers, porogens, and suspending agents. ,,− These have been shown to often still bear many unreacted pendant vinyl groups, , as detected by solid-phase NMR (δ 135 C H and 110  C H 2 ), , and quantitated by FTIR (1630 CC and 990 C CH cm -1 ), ,, or, less conveniently and reliably, , by chemical assay with bromine 30 or other reagents . A simple model of polymerization to account for this morphology would be (1) incorporation of divinylbenzene into propagating polymer chains, through reaction of one vinyl group as activated by the other; (2) further cross-linking reactions between those resulting polymer-bound vinyl groups that are actually adjacent, while others remain site isolated 20 and intact within the increasingly rigid cross-linked matrix.…”

“…Chemical Modification of 1 to PsCH 2 CH 2 X. Though typically thought a nuisance in chloromethylation (undergoing cationic polymerization/cross-linking and other side-reactions) , and other “traditional” functionalizations, residual vinyl groups on cross-linked polystyrene have in the past been functionalized by graft copolymerization of functional monomers , and by bromination, epoxidation, and ozonolysis . A few particular instances of addition of H−X have also been described, as will be mentioned below.…”

“…For simplicity, versatility, controlled architecture, and even distribution and ready accessibility of functional groups, functional polymers are generally better prepared by modification of preexisting polymers, rather than by copolymerization with specialty monomers. ,− To date, chloromethylation of cross-linked polystyrene, followed by nucleophilic substitution, has been a very popular route. − However, serious problems arise from the carcinogenicity of the chloromethylation reagents; also, the stability of the polymer products is often limited, due to functional group heteroatoms being connected to the polymer backbone via only a weak benzylic bond that is subject to unwanted cleavage during many reaction or regeneration conditions. , More recently, other functional polymers have been reported that incorporate ethylene (dimethylene) spacers for more stable attachments through non-benzylic primary bonds. , Such distancing from the polymer backbone may also confer further advantages of more mobile and accessible functional groups, ,, and thus greater catalytic or other activity of the functional polymer product. , However, their syntheses so far have required many steps and the use of toxic and/or expensive chemicals.…”

Carbohydrate Coated Polymer Particles: Preparation and Protein‐binding Studies

“…46 Therefore, in this study, the specific capacities were generally chemically titrated 44 or roughly evaluated from the weight increment of the product. 47,48 In the first step of the synthesis, the capacities of free amino residues of the PAHA particles were both titrated and determined by o-phthalic anhydride, as shown in Figure 3.…”

Packings for Size Exclusion Chromatography: Preparation and Some Properties

“…Therefore, the dry porosity of resins does not necessarily correspond to the swollen-state porosity. Two main methods are known to determine the porous structure of macroporous resins swollen by a solvent: thermoporometry, which is based on the dependence of the pore size on the freezing point of a filling solvent (84), and inverse size-exclusion chromatography (85). Another method to measure the pore size distribution of swollen gels, so called mixed-solute exclusion, is introduced by Kuga (86).…”