Poly-Diox

The other topic, which will be covered in this paper, was previously reviewed by Plesch at the lUPAC Symposium in Budapest 6, and more recently at the I-st lUPAC Symposium on Ring-Opening Polymerization held in Jablonna (1975) 2l In this part of our paper the structure of the end-groups in poly-Diox is described, and the mechanistic consequences of the alleged macrocyclic or linear structures of the isolated dead macromolecules is discussed. 

Worsfold 1 1 claimed that he could not any end-groups in poly-Diox formed, although a triplet from a CH CHoO group is seen in the H-NMR spectrum given innis pj (C H5) 0+SbClg, concluaed, thal... 

Thus, because of the existing controversy, whether and when poly-Diox contain the end-groups, and because of the far reaching conclusions based on either macro-cyclic or linear structures of the isolated poly-Diox, we reinvestigated recently this problem. 

The second end-group, introduced upon a termination reaction, was observed by FPT- H-NMR for samples of poly--Diox, prepared from a perdeuterated Diox(Diox-d ). This approach decresases an over-all number of protons in the sample and increases proportion of protons in the end-groups. Application of the Fourier-Pulse-Transform method for accumulation of the spectra enhanced the... 

Structure of Poly-Diox (cyclic vs linear) and Mechanism of Polymerization 45. ... 

Poly(MA-CDA) was synthesized by a free radical copolymerization of maleic anhydride and 7,12-diox-aspiro-[5,6]-dodec-9-ene, followed by hydrolysis in... 

T.M. Brown, J.S. Kim, R.H. Friend, F. Cacialli, R. Daik, and W.J. Feast, Built-in electroabsorption spectroscopy of polymer light-emitting diodes incorporating a doped poly(3,4-ethylene diox-ythiophene) hole injection layer, Appl. Phys. Lett., 75 1679-1681, 1999. 

The gauche states are also observed in crystalline polymers, polyoxymethy-lene6,7,157-160, polyoxyethylene6,7,161,162, poly-1,3-dioxolane163, and poly-1,3-dioxe-pane164 by X-ray analysis. 

Schuerch2) reviewed the medical application of synthetic poly-saccharides. Capozza199 reported that the poly-orthoester prepared from 2-ethoxy-4-hydroxymethyl-l,3-diox-olane in the presence of add are useful as slow-release agents for drugs. Poly-2,6,7-trioxabicyclo[2.2.1]heptane VIII showed the same behavior200). 

In the preceding sections, NMR data were discussed indicating that poly-1,3-diox-olane grows on the linear macromolecules. The corresponding active species can either be oxonium ions or alkoxycarbenium ions ... 

Poly(AB) is active [103] in the UV induced polymerization of styrene in diox-ane solution. The solvent fiactionation of the resulting polymeric product has been proved to be constituted by a small amount of linear and graft poly(styrene), the main product being a crosslinked iwlymer, according to the occurrence of termination reactions involving polymer-bound growing chain and substituted benzyl radicals. 

A series of morphological images captured during isothermal crystallization of poly(p-diox-anone), PDS, at 85°C by (a) AFM, (b) HSOM, and (c) SALS. 

Greisler and co-workers have examined the use of commercial absorbable fibers for the production of absorbable vascular grafts. Using multifilament yam of 90/10 poly(glycolide-co-/-lactide) and monofilaments of poly-p-diox-anone to produce totally absorbable grafts was shown to be impractical. This is because of the insufficient strength retention profile of these grafts postoperatively. 

Composite conductive fibers based on poly(3,4-ethylene-diox)d hiophene]-polystyrene sulfonic acid (PEDOT-PSS) solution blended with polyacrylonitrile (PAN] were obtained via wet spinning. The influence of draw ratio on the morphology, structure, thermal degradation, electrical conductivity, and mechanical properties of the resulting fibers was investigated. The results revealed that the PEDOT-PSS/PAN composite conductive fibers crystallization, electrical conductivity and mechanical properties were improved with the increase of draw ratio. The thermal stability of the fibers was almost independent of draw ratio, and only decreased slightty with draw ratio. Besides, when the draw ratio was 6, the conductivity of the PEDOT-PSS/PAN fibers was 5.0 S cm, ten times the conductivity when the draw ratio was 2 (Fig 5.10]. ... 

PLL A-8-poly (1,5-diox- 37 Phosphate-buffered solution Solid [192, 193]... 

Comparison of BF (calcd.) and FP (NMR) of poly--1,3-Diox, prepared from perdeuterated Diox(-d ). Polymerization conditions CH,N0, solvent, -15 , 12 hrs. ... 

Poly(3-phenylquinoxaline-2,7-diyl-3-phenylquinoxaUne- 7.2- diyl-1,4-phenylene-1,3-dioxoisoindoline-2,5-diylcarbonyl- 1.3- diox oisoindoline-5,2-diyl-1,4-phenylene) 533 Dynamic method, heating rate 5 K/min 111... 

Sridhar, S., Smitha, B., Latha, U. S. M., and Ramakrishna, M. 2004. Pervaporation of 1-4 diox-ane water mixtures using poly(vinylalcohol) membranes crosslinked with toluylene-2,4-diisocyanate. J. Polym. Mater. 21 181-188. 

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