ISSN:
1022-1336
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Poly(propylene glycol) [α-hydro-ω-hydroxypoly(oxypropylene)] of number-average molar mass M̄n ≈ 2000 g · mol-1 (PPG2000) was cyclised with high conversion (ca. 75%) by reaction with dichloromethane in the presence of powdered KOH. The cyclic product was separated from chain extended polymer by preparative GPC, giving an overall yield of polymer (M̄n ≈ 2000 g · mol-1, narrow molar mass distribution) in excess of 50%. Characterisation by analytical GPC and 13C NMR spectroscopy confirmed cyclisation. DEPT and 1H-coupled NMR spectra were used to show that the links in cyclic poly(oxypropylene) were 77% single acetal, 12% double acetal and 11% triple acetal (or higher). This complexity probably results from competitive reaction with water introduced with KOH.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/marc.1997.030181212
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