Phosphate Containing Polymers

Polymers with phosphate linkages include poly(phosphate)s, poly-(phosphonate)s, and poly(phosphite)s. 

The versatility of these polymers comes from the versatility of the phosphorus atom, which is known for a multiplicity of reactions. Its bonding can involve the 3p orbitals or various 3s - 3p hybrids, spd hybrids are also possible because of the accessible d orbitals. Thus, the physicochemical properties of the poly(phosphoester)s can be readily changed by varying either the R or R2 group. 

The P-O-C group in the backbone lowers the glass transition temperature of the pol5mier and may confer solubility in common organic solvents, which is desirable for easy characterization and processing. 

The biodegradabUity of the polymer is due primarily to the physiologically labile phosphoester bond in the backbone of the pol5mier. By manipulating the backbone or the side chain, a wide range of biodegradation rates are attainable. 

Because phosphorus can be pentavalent, drug molecules or other biologically active substances can be chemically linked to the polymer. For example, drugs with carboxyl groups may be coupled to the phosphorus via an ester bond, which is hydrolyzable (31). 

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Recent research into PPE scaffolds for tissue engineering has been more focused on bone tissue regeneration because of the attractive osteoinductive potential of phosphate-containing polymers. 

Of the phosphorus-containing polymers the polyphosphates have been known for many years. Aluminium phosphate had been used in the manufacture of heat-resistant silica-fibre-reinforced laminates. 

Alkalinity boost chemistries typically are based on adjunct products containing primarily potassium hydroxide (for maximum solubility) or sodium hydroxide (for lowest cost), although sodium carbonate is still used in certain limited applications. These adjuncts may also contain (in almost any combination) smaller percentages of tannins, sodium ligonsulfonate, phosphate or polymers. 

Laundry detergent may also contain polyethylene glycol, a polymer that prevents dirt from redepositing on the clothes. This function used to be the job of phosphates. Another polymer used for this purpose is carboxy methyl cellulose, which is derived from natural cellulose but is very soluble in water. 

Surprisingly, phosphorus when combined with bromine is effective in nonoxygen containing polymers. In another reference, a mixture of a brominated compound and a triaryl phosphate was claimed to be effective in HIPS where antimony oxide is generally required as a synergist for bromine (ref. 7). 

Figure 17.17 Schematic representation of a single-compartment glucose/02 enzyme fuel cell built from carbon fiber electrodes modified with Os -containing polymers that incorporate glucose oxidase at the anode and bilirubin oxidase at the cathode. The inset shows power density versus cell potential curves for this fuel cell operating in a quiescent solution in air at pH 7.2, 0.14 M NaCl, 20 mM phosphate, and 15 mM glucose. Parts of this figure are reprinted with permission from Mano et al. [2003]. Copyright (2003) American Chemical Society.

Low-molecular-weight carboxyl-containing polymers have been used to control the deposition of calcium phosphate (2-8). These polymers also function as... 

Although halogen-containing polymers, such as PVC and ptfe, and phosphorus-containing phosphonate and phosphate polymers... 

Fig. 19.a Proposed structure of the HAP firmly attached to the polymer surface having phosphate-containing graft chains, b Binding between the graft chains and the HAP crystal... 

Figure 7. The analysis of one- and two-chain rhGH by reversed-phase HPLC at neutral pH. The chromatography was performed on a Polymer Laboratory PLRP-S column using phosphate-containing mobile phases, and eluted with an acetonitrile linear gradient.

Ferrocene has been reported to be very effective as a soot reducing agent in combustion [42 — 44]. Thus, when ferrocene compounds are incorporated in a fire retardant polymer, such as a phenolphthalein-based polymer and poly(phosphate ester)s, they have shown added advantages in that they promote extinction and reduce smoke formation by accelerated char reduction [45, 46]. The synthesis of such ferrocene-containing poly(phosphate ester)s was achieved by interfacial polycondensation using a phase transfer catalyst [47]. Accordingly, l,l -bis(p-hydroxy-phenylamido)ferrocene and l,l -bis(p-hydroxyphenylcarbonyl)ferrocene underwent condensation with various aryl phosphoroic acid dichlorides to yield two series of ferrocene-containing polymers, i.e., poly (amide-phosphate ester)s 38a and poly(ester-phosphate ester)s 38b respectively, as shown in Scheme 10-17. 

Also, the solid particles may contain water-soluble substances, which undergo leaching and specific adsorption. Reference [1865] reports the IEP of phosphate-containing goethite. One sample studied in [32] contained sulfate and phosphate, and its IEP and PZC differed significantly. The silica studied in [2929] was prepared in the presence of a nonionic surfactant. No attempt was made to remove that surfactant from the final product. Phosphate-doped titania was studied in [2930] and polymer-stabilized latex was studied in [2931], A few results presented above have been cited by others as pristine PZCs/IEPs. 

The presence of phosphate significantly improved the catalytic activity. The polymer MI also increased, and the MW distribution shifted to generally lower average MW. Presumably, some chromium became attached to phosphate, which in turn pulled electron density away from the metal, making it more reactive. When activated at 700 °C, the phosphate-containing catalyst continued to embellish the low-MW side of the... 

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