Über die Stabilität Von Copolymeren aus 1,3,5-Trioxan mit verschiedenen Lactonen

Der thermische Abbau von Copolymeren aus 1,3,5-Trioxan und den Lactonen β-Propiolacton (3-Propanolid), Pivalolacton (2,2-Dimethyl-3-propanolid) und e-Caprolacton (6-Hexanolid) wurde untersucht. Der langsame und vollstandige Abbau der Copolymeren wird zuruckgefuhrt auf 1 eine statistische acidolytische Kettenspaltung durch Carboxyl-Endgruppen, 2 die Abspaltung von Acrylsaure an den sauren Endgruppen, 3 die statistische Kettenspaltung durch Pyrolyse von Esterbindungen vor allem in Sequenzen aus mehreren β-Propiolactonbausteinen. Die Teilreaktionen (1) und (2) konnen durch Zusatz von Butandiol-Diglycidylather-(1,4-Bis(2,3-epoxypropoxy)butan) oder N-(2-Naphthyl)anilin oder von Epoxiden stark ve…

The polyamides 3–5 were synthesized from α,ω-diamino-substituted oligo(oxyethylene)s (1) and bis-chlorides of dicarboxylic acids (2). As copolymers with defined sequences they contain up to five oxyethylene units per repeating unit. Hereby properties like solubility, thermal stability and complexing ability towards alkali metal cations are influenced.

The thermal degradation of poly(oxycarbonylpentamethylene), (poly-e-caprolactone), (3), was investigated at 220°C and 80 mm Hg under nitrogen. 3 was found to be thermally much more stable than poly(oxycarbonylethylene), (poly-β-propiolactone), (1), although it decomposed faster than poly(oxycarbonyl-1,1-dimethylethylene), (polypivalolactone), (2). The reaction was of the first order with a rate constant of k=6,2.10−4 min−1 and proceeded via a “zipper mechanism” to yield monomeric e-caprolactone. Der thermische Abbau von Poly(oxycarbonylpentamethylen), (Poly-e-caprolacton), (3), wurde bei 220°C im Stickstoffstrom bei 80 mm Hg untersucht. Dabei wurde gefunden, das 3 thermisch wesentlich stabi…

Beziehung zwischen molekulargewicht und viskosität von polyoxymethylenen in dimethylformamid und in hexafluoraceton-sesquihydrat. 33. Mitt. über polyoxymethylene

Polyamides 3 containing constant and definite numbers of oxyethylene units were prepared by condensation polymerization of suitable diamines and diesters, both of which containing oxyethylene units. The polymer structure was determined by IR and 1H NMR spectroscopy. Almost all polymers are crystals melting at ≈ 40°C and show a complexation ability towards alkalimetal cations. It was also found that diesters containing oxyethylene units show a higher condensation rate than alkylene diesters, which is explained by an inductive effect of the ether oxygene. However, no remarkable difference in the condensation rate was found between diamines containing oxyethylene units and the corresponding al…

The thermal degradation of poly(oxycarbonylethylene) (poly-β-propiolactone) has been investigated within a temperature range of 180–220°C and under various pressures. The degradation begins with a considerable decrease in molecular weight, followed by an accelerating formation of acrylic acid. The reaction involves the following steps: 1 Random chain scission of polymer chains by typical ester pyrolysis with the formation of fragments one of which containing a carboxylic group the other one a CC-double bond at the chain end (Eq. (1)). 2 Formation of the volatile acrylic acid by scissions at the chain end, the amount of acrylic acid or the weight-loss increasing with the number of fragmentat…