Carboxylated PPO

The aryl bromides undergo facile metalation with butyl lithium to produce aryllithium derivatives with the expected organometallic activity.9 For example, reaction of lithiated PPO with carbon dioxide produces a carboxylated PPO which exhibits unique blending characteristics18. 

PMMA/PEO, polyethylene oxide PC/lithium salt of sulfonated polystyrene PS/polyphenylmethyl siloxane Chlorinated PE/chlorinated polybutadiene PS/carboxylated PPO PPO/poly(alpha-methylstyrene)... 

So far it has been assumed, without any proof, that sulfonic groups in SPPO are attached to aromatic rings. In principle, sulfonic groups could also be attached to methyl groups as in case of other modified PPO polymers, for example, carboxylated PPO or methyl ester carboxylated PPO [22]. Acid-base and conductimetric titrations do not allow distinguishing between aryl and methyl substituted PPO. On the other hand, proton nuclear magnetic resonance ( H NMR) and infrared (IR) spectroscopy provide more information on the structure of SPPO. These techniques can also be used for determination of the DS of SPPO. 

In order to improve the selectivity of PPO Story and Koros prepared carboxylated PPO. The thus modified polymer and its methyl ester were substituted primarily at the methyl side chain position. They found that carboxylation decreased the permeability to CO2 and increased the permeability ratio of PPO for CO2/CH4 (Table 7). 

Table 7. Permeability and selectivity for the gas pair CO2/CH4 of dense films prepared from carboxylated PPO ( CPPO ) measured at 35 C ...

The permeability and permeability ratio of dense films made from SPPOBr of varied degrees of sulfonation and bromination are shown in Table 12. Performances of carboxylated PPO (CPPO) and sulfonated PPO (SPPO) dense films are also presented for comparison. 

Bromobenzyl groups were introduced into PPO by radical bromination of the methyl groups. The PPO bromobenzyl groups and PECH chloromethyl groups were then esterified under phase-transfer-catalyzed reaction conditions with the potassium carboxylates just described. This procedure has been described previously (29). The sodium salt of 4-methoxy-4 -hydroxybiphenyl was also reacted with PECH (no spacer). 

Analogous alkoxides, phenoxides, and carboxylates will also initiate the ROP of epoxides, all forming propagating alkoxide species.779 Block copolymers of epoxides with /3-butyrolactone have been prepared via the addition of EO or PO to living poly(ester) chains.782 The oxygen-bound enolate of living PMMA will also react with epoxides to yield diblocks such as PEO-b-PMMA and PPO-b-PMMA (Mn= 12,800, Mw/Mn = 1.16) 787... 

The specimens were coated with a blend of the carboxylated polyester and second polymer in a solvent (10% solids), which, when possible, consisted of a conventional lacquer solvent (74.2% toluene, 7.4% butyl alcohol, 7.4% Solvesso 100 solvent, 3.7% ethyl acetate, 3.7% butyl acetate, and 3.6 Cellosolve acetate). If the second polymer was not soluble (polysulfone, polycarbonates, PPO), chloroform was used. The coatings were dried for 1 hour at room temperature and then for 2 hours in an oven at 115°C. The coating thickness was about 0.5 mil. 

Figures 4.49 and 4.50 show the DSC curves at different annealing temperatures and the phase diagram for a blend of polystyrene (M , = 115 000) and carboxylated poly(phenylene oxide) (PPO) with molar fraction 8.0% carboxyla-tion content.

Preparing PCMs or the basic polymer for blend PCMs by carboxylation of PPO-Li with carbon dioxide... 

End-functional polymers can also be prepared by modification of existing polymers. For example, PPO was successfully end-capped by epoxide (PPO-E) and anhydride (PPO-A), respectively [36, 37]. Because of the reactivity of the epoxide with the carboxylic acid end groups of PBT, PPO-E was used as a reactive compatibilizer for PPO/PBT blends. Similarly, during melt blending with PA 6,6, the anhydride end-groups of PPO-A were found to react with the amine end-groups of polyamide. As a rule, PPO-b-PBT and PPO-b-PA 6,6 copolymers were formed at the interface their blocks were interconnected by an ester and an imide bond, respectively. 

Blends of PPO with PS containing sulfonated and carboxylated groups have been reported in various studies [394-396]. The miscibility of sulfonated PS with PPO, sulfonated PPO with PS and blends of the sulfonated polymers was reported by Hseih and Peilfer [394]. Miscibility was maintained with sulfonation levels up to 2-4mol% for PS with sulfonated PPO and sulfonated PS with PPO. When both polymers were sulfonated, phase separation occurred at higher levels (> 10mol% sulfonation). The miscibility can be influenced by counter ion, as noted in a comparison of a Zn + neutralized sulfonic acid modified PS, which exhibited a larger miscibility window with PPO than the Na neutralized coimterpart [396]. Syndiotactic polystyrene was noted to be miscible over the entire composition range in amorphous blends with PPO, where the Tg versus composition followed the Fox equation predictions [397]. Isotactic polystyrene miscibility with PPO has also been observed, with crystallization and orientation data reported on the blend [398]. 

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