In 1997, a research programme was initiated to assess the ability of nanospheres (NS) to improve the biodelivery of a new insecticide to plants. Stable polymeric NS, with a size near 135 nm and an encapsulation rate in the range of 3.5%, have been obtained using a nanoprecipitation method with Eudragit S100 polymer. Biological studies have been performed on cotton plants infested with aphid, to estimate the direct contact efficacy of NS formulations on the insects and the systemicity of the encapsulated active ingredient and its level of penetration through the plant, compared to a classical suspension used as a reference. Results indicate that NS formulations are not so good as the reference in terms of speed of action and sustained release. Nevertheless, NS formulation performed better than the reference to enhance the systemicity of the AI and improve its penetration through the plant. It is concluded that the NS do not provide a controlled release of AI but, due to their small size, they enhance the penetration in the plant compared to the classical suspension.

The properties of paper sheets can be tuned by adjusting the surface or bulk chemistry using functional polymers that are applied during (online) or after (offline) papermaking processes. In particular, polymers are widely used to enhance the mechanical strength of the wet state of paper sheets. However, the mechanical strength depends not only on the chemical nature of the polymeric additives but also on the distribution of the polymer on and in the lignocellulosic paper. Here, we analyze the photochemical attachment and distribution of hydrophilic polydimethylacrylamide-co-methacrylate-benzophenone P(DMAA-co-MABP) copolymers with defined amounts of photoreactive benzophenone moieties in model paper sheets. Raman microscopy was used for the unambiguous identification of P(DMAA-co-MABP) and cellulose specific bands and thus the copolymer distribution within the cellulose matrix. Two-dimensional Raman spectral maps at the intersections of overlapping cellulose fibers document that the macromolecules only partially surround the cellulose fibers, favor to attach to the fiber surface, and connect the cellulose fibers at crossings. Moreover, the copolymer appears to accumulate preferentially in holes, vacancies, and dips on the cellulose fiber surface. Correlative brightfield, Raman, and confocal laser scanning microscopy finally reveal a reticular three-dimensional distribution of the polymer and show that the polymer is predominately deposited in regions of high capillarity (i.e., in proximity to fine cellulose fibrils). These data provide deeper insights into the effects of paper functionalization with a copolymer and aid in understanding how these agents ultimately influence the local and overall properties of paper.

In 1997, a research program was initiated in the laboratories to assess the ability of nanosperes (NS) to improve the biodelivery of new active ingredients (AI) to plants. The goal was to obtain stable poly (epsilon-caprolactone) NS (PeC-NS) with the smallest size and the largest amount of encapsulated AI, using a nanoprecipitation method. The smallest particles obtained were in the range of 200-250 nm. The highest encapsulation is obtained with Montanox 80 as surfactant and is between 5-10% (expressed in per cent weight relative to the total weight of polymer), which corresponds to an encapsulation yield of 95%. There is no desorption of the AI with time. In contrast, the dilution of the NS suspension in water is followed by a large removal of the AI in the aqueous phase. This suggests that NS are complex dynamic systems in equilibrium with the external medium and disturbances of this system lead to a loss of AI.

other polycyclic compounds other polycyclic compounds Q 1150 -129Liquid Crystalline Coronene Derivatives with Extraordinary Fluorescence Properties.-The title compounds (IV), prepared starting from readily available perylene derivative (I), form depending on the alkyl substituents discotic mesophases and combine properties of both dyes and liquid crystals. They form aggregates in a solid matrix whose photoluminescence wavelength varies depending on the tempering process used. Thus, they are promising compounds for the preparation of multicolored displays on the basis of organic luminescent diodes. Compounds (IV) can be transformed into hitherto unknown dialkylcoronene derivatives, e.g. (V). -(ROHR, U.; SCHLICHTING, P.; BOEHM, A.; GROSS, M.; MEERHOLZ, K.; BRAEUCHLE, C.; MUELLEN, K.; Angew.