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- Blauer Engel (1)
- Desorption (1)
- FP (1)
- GFRP (1)
- Hydrothermal Ageging (1)
- Interfacial Strength (1)
- Interphase (1)
- Laserdrucker (1)
- Partikelemissionen (1)
- UFP (1)
Organisationseinheit der BAM
Alkyl polyglycosides today represent the most important sugar surfactant. Nonionic sugar surfactants produced via different synthetic routes are mixtures of alkyl homologues, oligomers, anomers and isomers. Alkyl homologues and oligomers of alkyl mono- and diglucosides were separated by reversed-phase high-performance liquid chromatography (HPLC) with methanolwater as the mobile phase using a gradient elution. The gradient was optimized in respect to a simultaneous separation of alkyl glycosides according to their alkyl chain length and alkyl polyoxyethylene glucosides with regard to their length of the polyoxyethylene spacer. The separation of alkyl glycosides into ?- and ?-anomers was carried out by normal-phase HPLC with isooctaneethyl acetate (60:40, v/v)2-propanol in the gradient mode. Light scattering detection was used. Matrix-assisted laser desorption ionization time-of-flight mass spectra of alkyl glucosides and dodecyl glucosides with oxyethylene spacer groups are presented.
Epoxy R-Glass Fiber-Reinforced Polymer (GFRP) composite plates were hydrothermally aged at 60 ◦C for 23, 75, and 133 days. The water content reached 0.97 wt%, 1.45 wt% and 1.63 wt%, respectively. The studied GFRP matrix was inert to hydrolysis or chain scission, allowing for investigation of irreversible changes in the fiber-matrix interphase due to hydrothermal aging upon re-drying. During each period, a subset of the specimens was removed from the water bath and dried in a chamber. The weight loss upon drying was explained with epoxy leaching (impurities), sizing-rich interphase hydrolysis, glass fiber surface hydrolysis, accumulated degradation products escaping, and water changing state from bound to free. The influence of hydrothermal aging on the fiber-matrix interfacial properties was investigated. Lower interfacial strength of hydrothermally aged (wet)
samples was attributed to plasticization of the epoxy, plasticization and degradation of the sizing-rich interphase (including formation of hydrolytic flaws), and hydrolytic degradation of the glass fiber surface. The kinetics of epoxy-compatible epoxysilane W2020 sizing-rich interphase hydrolysis provided an estimate of ca. 1.49%, 4.80%, and 8.49% of the total composite interphase degraded after 23, 75, and 133 days, respectively. At these conditions, the interface lost 39%, 48%, and 51% of its strength. Upon re-drying the specimens, a significant part of the interfacial strength was regained. Furthermore, an upward trend was observed, being 13%, 10% and 3% strength, respectively; thus, indicating a possibility of partial recovery of properties.
Partikelemissionen aus Laserdruckern sind seit längerem bekannt und wurden bislang als Feinstaubmasse bei der Prüfwertvergabe für den Blauen Engel begrenzt. Seit einigen Jahren weiß man, dass neben den Feinstaubpartikeln auch ultrafeine Partikel beim Betrieb von Laserdruckern emittiert werden. Diese Emissionen lassen sich nur eingeschränkt bis gar nicht über Nachrüstfilter am Druckgerät minimieren. Das Umweltbundesamt (UBA) hat dies zum Anlass genommen, die Prüfvorgaben für den Blauen Engel im Hinblick auf die Erfassung ultrafeiner Partikel anzupassen und zu verschärfen. UBA hat hierzu einen Forschungsauftrag an die Bundesanstalt für Materialforschung und -prüfung (BAM) vergeben. Testverfahren und Prüfvorgaben sind nunmehr erarbeitet und werden im Beitrag vorgestellt. Die geänderten Prüfbedingungen sollen ab 2013 in die Prüfvorgabe eingeführt werden. Etwa drei Viertel der derzeit am Markt erhältlichen Laserdrucker werden die strengen Prüfvorgaben nicht erfüllen können.