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- Blends (2)
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- 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (1)
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- 6 Materialchemie (3)
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- 9 Komponentensicherheit (1)
Wie viele Forschergruppen, haben auch wir uns das langfristige Ziel gesetzt, einen Beitrag bei der Beantwortung der Frage zu leisten, was Hunde riechen, wenn sie Krebs erschnüffeln.
Dabei sollen die Hunde nicht nur anzeigen, ob eine Atemluftprobe positiv oder negativ ist, sondern sie sollen auch aktiv eingebunden werden in den systematischen Suchprozess nach detektierbaren Biomarkern. So ist geplant, dass mittels eines präparativen Fraktionssammlers definierte Schnitte des Gaschromatogramms einzeln oder in möglichen Kombinationen auf das Adsorbervlies gebracht werden, um im Hundetraining eingesetzt zu werden. In analoger Weise könnte auch mit spezifischen Kandidatensubstanzen verfahren werden.
Pyrolysis, fire behaviour and mechanical properties of a blend of poly(butylene terephthalate) (PBT) with a phosphorus polyester (PET-P-DOPO) are investigated and compared with PBT/aluminium diethylphosphinate (AlPi-Et) composites. The PBT/PET-P-DOPO is immiscible and exhibits gas-phase and condensed-phase activity, whereas AlPi-Et in PBT results mainly in flame inhibition. Only higher loadings of AlPi-Et yield significant condensed-phase activity. Using the same phosphorus content, PBT/PET-P-DOPO and PBT/AlPi-Et exhibit similar reductions in fire load (22%) and flame spread (17% assessed by fire growth rate, FIGRA), compared with PBT. In contrast to AlPi-Et, the addition of PET-P-DOPO does not decrease the tensile strength of PBT. Thus, PET-P-DOPO is an interesting alternative to low-molecular-weight flame retardants.
PET-P-DOPO is a phosphorus-containing polyester prepared from the glycol ether of the hydroquinone derivative of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and dimethyl terephthalate. PET-P-DOPO and a blend of PBT with PET-PDOPO were investigated with respect to pyrolysis and fire behavior. PET-P-DOPO achieves a V-0 rating in the UL 94 test and exhibits a high LOI of 39.3%. The outstanding flame-retardant properties of PET-P-DOPO are the result of three different mechanisms (flame inhibition, charring and a protection effect of the intumescent char) that are active in PET-P-DOPO. The fire load and the peak of heat release rate (pHRR) are reduced to 34% and 17%, respectively. The char exhibits an intumescent multicellular structure enabling it to act as an efficient protection layer. As PET-P-DOPO is immiscible with PBT, the blend shows a lower breaking elongation than pure PBT. Compared to pure PET-P-DOPO, the flame retardancy of the blend is decreased according to the fraction of PET-P-DOPO used. Nevertheless, the flame-retardancy of PET-P-DOPO in the blend was good enough to compete with PBT flame-retarded by AlPi-Et (aluminum diethylphosphinate) that was used as a Benchmark.
Flame retarded poly(butylene terephthalate) (PBT) is required for electronic applications and is mostly achieved by low molar mass additives so far. Three phosphorus-containing polyesters are suggested as halogen-free and polymeric flame retardants for PBT. Flame retardancy was achieved according to cone calorimeter experiments showing that the peak heat release rate and total heat evolved were reduced because of flame inhibition and condensed-phase activity. The presented polymers containing derivatives of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide form immiscible blend systems with PBT. Shear-rheology shows an increase in storage moduli at low frequencies. This is proposed as quantitative measure for the degree of phase interaction. The phase structure of the blends depends on the chemical structure of the phosphorus polyester and was quite different, depending also on the viscosity ratio between matrix and second phase. A lower viscosity ratio leads to two types of phases with spherical and additionally continuous droplets. Addition of the flame retardants showed no influence on the dielectric properties but on the mechanical behavior. The polymeric flame retardants significantly diminish the impact strength because of several reasons: (1) high brittleness of the phosphorus polyesters themselves, (2) thermodynamic immiscibility, and (3) weak phase adhesion. By adding a copolymer consisting of the two base polymers to the blend, an improvement of impact strength was obtained. The copolymer particularly acts as compatibilizer between the phases and therefore leads to a smaller phase size and to a stronger phase adhesion due to the formation of fibrils.
The analytical utility of a new and simple to use ionization method, matrix-assisted ionization (MAI), coupled with ion mobility spectrometry (IMS) and mass spectrometry (MS) is used to characterize a 2-armed europium(III)-containing poly(ethylene glycol) (Eu-PEG) complex directly from a crude sample. MAI was used with the matrix 1,2-dicyanobenzene, which affords low chemical background relative to matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI). MAI provides high ion abundance of desired products in comparison to ESI and MALDI. Inductively coupled plasma-MS measurements were used to estimate a maximum of 10% of the crude sample by mass was the 2-arm Eu-PEG complex, supporting evidence of selective ionization of Eu-PEG complexes using the new MAI matrix, 1,2-dicyanobenzene. Multiply charged ions formed in MAI enhance the IMS gas-phase separation, especially relative to the singly charged ions observed with MALDI. Individual components are cleanly separated and readily identified, allowing characterization of the 2-arm Eu-PEG conjugate from a mixture of the 1-arm Eu-PEG complex and unreacted starting materials. Size-exclusion chromatography, liquid chromatography at critical conditions, MALDI-MS, ESI-MS, and ESI-IMS-MS had difficulties with this analysis, or failed.