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Nowadays, both micro- and nanomaterials are processed in cement to improve application properties or reduce cement consumption in concrete. The present study deals with the impact of nanostructured SiO2, TiO2and milled slags in cement composites on material properties, aging resilience and release behaviour into the environment. In this context, hydrated and hardened cement pastes were weathered artificially by means of the standardised capillary suction of de-icing solution and repeated freeze–thaw cycle test method. Mineralogical, physical, mechanical and chemical properties as well as hydration products were analysed by electron microscopy, mercury intrusion porosimetry, thermogravimetry as well as differential scanning calorimetry and ultrasonic propagation analysis. Release characterisation was performed concerning weathering-induced fragment release into the liquid phase by gravimetry and sanding-induced particle release into the air by gravimetry, differential electrical mobility analyses, time of flight spectrometry, condensation nuclei counting and electron microscopy. Freeze–thaw weathering led for all cement composites to considerable but different progressed deteriorations. The worst material performance was observed for pure cement and the cement composite with state of the art ground granulated slag. The cement composites with nanostructured SiO2and activated ground granulated slag showed a higher durability and less deteriorations. These effects could be explained by structure density, porosimetry and the formed hydration products. Furthermore, it was shown that weathering-induced changes in the material properties lead to significant changes concerning sanding-induced particle release into air. In summary, this study investigated the consequences of (nano)-materials, which modulate the recrystallization during hardening of cement pastes to a solid, internally nanostructured material, on multi-structural release. In this context, critical stress scenarios, which are encountered during intended use, were simulated. The transforming synthesis differentiates this case study from almost all other release studies for nanomaterials, which typically assess polymer nanocomposites, where nanomaterials act as additives, pigments or fillers in an otherwise unchanged matrix.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is gaining acceptance in clinical practice, but detailed information about the microinjection pump (MIP®), the generated aerosol and drug distribution is missing. Ex vivo granulometric analyses by means of laser diffraction spectrometry were performed for MIP®aerosol characterization. Beside the standard operation conditions, the impact of the volumetric liquid flow rate on the aerosol characteristics was investigated with different liquids. Granulometric results as well as the local drug distribution were verified by ex vivo gravimetric analyses. On the basis of determined MIP®characteristics, the aerosol droplet size, which is necessary for a homogenous intra-abdominal drug distribution, was calculated. Granulometric analyses showed that the MIP®aerosol consists of a bimodal volume-weighted particle size distribution (PSD3) with a median droplet diameter of x50,3= 25 µm. Calculations reveal that the droplet size for a homogenous intra-abdominal drug distribution during PIPAC therapy should be below 1.2 µm. We show that >97.5 vol% of the aerosolized liquid is delivered as droplets with ≥3 µm in diameter, which are primarily deposited on the surface beneath the MIP®by gravitational settling and inertial impaction. These findings were confirmed by ex vivo gravimetric analyses, where more than 86.0 vol% of the aerosolized liquid was deposited within a circular area with a diameter of 15 cm. The granulometric aerosol properties, as well as the aerodynamic conditions achieved by standard MIP®operation, do not support the idea of widespread or homogenous drug distribution in the abdominal cavity.