Refine
Year of publication
Institute
- Institut fuer Angewandte Polymerchemie (32) (remove)
Has Fulltext
- no (32)
Document Type
- Article (20)
- Patent (8)
- Book (2)
- Conference Proceeding (2)
Keywords
- Minor chemistry (1)
- Physical chemistry (1)
- Physical chemistry basics (1)
- Physical chemistry starters (1)
- Thermodynamics as minor (1)
- biodegradable polymers (1)
- deficit irrigation (1)
- elastomers (1)
- glycine (1)
- hydrogel (1)
Is part of the Bibliography
- no (32)
Light-stimulated hydrogel actuators with incorporated graphene oxide for microfluidic applications
(2015)
Abstractauthoren Graphene oxide (GO) nanoparticles were incorporated in temperature-sensitive Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels. The nanoparticles increase the light absorption and convert light energy into heat efficiently. Thus, the hydrogels with GO can be stimulated spatially resolved by illumination as it was demonstrated by IR thermography. The temporal progression of the temperature maximum was detected for different concentrations of GO within the polymer network. Furthermore, the compatibility of PNIPAAm hydrogels with GO and cell cultures was investigated. For this purpose, culture medium was incubated with hydrogels containing GO and the viability and morphology of chinese hamster ovary (CHO) cells was examined after several days of culturing in presence of this medium.
Die Erfindung betrifft eine schwefelvernetzbare Kautschukmischung, deren Vulkanisat und einen Fahrzeugreifen. Die schwefelvernetzbare Kautschukmischung enthält wenigstens die folgenden Bestandteile: - wenigstens einen Dienkautschuk; und - 10 bis 300 phr wenigstens einer Kieselsäure; und - 1 bis 30 phf wenigstens eines Silans A mit der allgemeinen Summenformel A-I) A-I)(R1)oSi-R2-(S-R3)q-S-X; und - 0,5 bis 30 phf wenigstens eines Silans B mit der allgemeinen Summenformel B-I) B-I) (R1)oSi-R2-(S-R3)u-S-R2-Si(R1)o wobei q =1, 2 oder 3 ist; und u = 1, 2 oder 3 ist; und X ein Wasserstoffatom oder eine –C(=O)-R8 Gruppe ist wobei R8 ausgewählt ist aus Wasserstoff, C1-C20 Alkylgruppen, vorzugsweise C1-C17, C6-C20- Arylgruppen, vorzugsweise Phenyl, C2-C20-Alkenylgruppen und C7-C20-Aralkylgruppen.
Die Erfindung betrifft eine schwefelvernetzbare Kautschukmischung, deren Vulkanisat und einen Fahrzeugreifen.Die schwefelvernetzbare Kautschukmischung enthält wenigstens die folgenden Bestandteile:- wenigstens einen Dienkautschuk; und- 10 bis 300 phr wenigstens einer Kieselsäure ; und- 1 bis 30 phf wenigstens eines Silans A mit der allgemeinen Summenformel A-I)und- 0,5 bis 30 phf wenigstens eines Silans B mit der allgemeinen Summenformel B-I)wobei u gleich 0, 1, 2 oder 3 und v gleich 0 oder 1 ist.
Nacre-mimetic nanocomposites based on high fractions of synthetic high-aspect-ratio nanoclays in combination with polymers are continuously pushing boundaries for advanced material properties, such as high barrier against oxygen, extraordinary mechanical behavior, fire shielding, and glass-like transparency. Additionally, they provide interesting model systems to study polymers under nanoconfinement due to the well-defined layered nanocomposite arrangement. Although the general behavior in terms of forming such layered nanocomposite materials using evaporative self-assembly and controlling the nanoclay gallery spacing by the nanoclay/polymer ratio is understood, some combinations of polymer matrices and nanoclay reinforcement do not comply with the established models. Here, we demonstrate a thorough characterization and analysis of such an unusual polymer/nanoclay pair that falls outside of the general behavior. Poly(ethylene oxide) (PEO) and sodium fluorohectorite form nacre-mimetic, lamellar nanocomposites that are completely transparent and show high mechanical stiffness and high gas barrier, but there is only limited expansion of the nanoclay gallery spacing when adding increasing amounts of polymer. This behavior is maintained for molecular weights of PEO varied over four orders of magnitude and can be traced back to depletion forces. By careful investigation via X-ray diffraction and proton low-resolution solid-state NMR, we are able to quantify the amount of mobile and immobilized polymer species in between the nanoclay galleries and around proposed tactoid stacks embedded in a PEO matrix. We further elucidate the unusual confined polymer dynamics, indicating a relevant role of specific surface interactions.
Synthetic mimics of natural high-performance structural materials have shown great and partly unforeseen opportunities for the design of multifunctional materials. For nacre-mimetic nanocomposites, it has remained extraordinarily challenging to make ductile materials with high stretchability at high fractions of reinforcements, which is however of crucial importance for flexible barrier materials. Here, highly ductile and tough nacre-mimetic nanocomposites are presented, by implementing weak, but many hydrogen bonds in a ternary nacre-mimetic system consisting of two polymers (poly(vinyl amine) and poly(vinyl alcohol)) and natural nanoclay (montmorillonite) to provide efficient energy dissipation and slippage at high nanoclay content (50 wt%). Tailored interactions enable exceptional combinations of ductility (close to 50% strain) and toughness (up to 27.5 MJ m⁻³). Extensive stress whitening, a clear sign of high internal dynamics at high internal cohesion, can be observed during mechanical deformation, and the materials can be folded like paper into origami planes without fracture. Overall, the new levels of ductility and toughness are unprecedented in highly reinforced bioinspired nanocomposites and are of critical importance to future applications, e.g., as barrier materials needed for encapsulation and as a printing substrate for flexible organic electronics.
Dargestellt und beansprucht ist eine Funkeinheit mit einem Funkbauteil, einer elektrisch leitfähigen Antenne und einem Kunststoffverbindungsmittel. Das Funkbauteil weist einen Antennenanschluss auf. Das Kunststoffverbindungsmittel weist ein erstes Elastomermaterial mit elektrisch leitfähigem Zusatzmaterial auf, so dass das Kunststoffverbindungsmittel elektrisch leitfähig ist. Das Kunststoffverbindungsmittel bildet eine mechanische und elektrisch leitfähige Verbindung zwischen dem Antennenanschluss und der Antenne. Weiterhin wird eine Vorrichtung mit einem ein Matrixmaterial mit oder aus einem zweiten Elastomermaterial und einer Funkeinheit beschrieben und beansprucht, wobei die Funkeinheit vollständig in das Matrixmaterial eingebettet ist. Die Vorrichtung kann insbesondere ein Fahrzeugreifen sein.
Throughout the last decade, and particularly in 2022, water scarcity has become a critical concern in Morocco and other Mediterranean countries. The lack of rainfall during spring was worsened by a succession of heat waves during the summer. To address this drought, innovative solutions, including the use of new technologies such as hydrogels, will be essential to transform agriculture. This paper presents the findings of a study that evaluated the impact of hydrogel application on onion (Allium cepa) cultivation in Meknes, Morocco. The treatments investigated in this study comprised two different types of hydrogel-based soil additives (Arbovit® polyacrylate and Huminsorb® polyacrylate), applied at two rates (30 and 20 kg/ha), and irrigated at two levels of water supply (100% and 50% of daily crop evapotranspiration; ETc). Two control treatments were included, without hydrogel application and with both water amounts. The experiment was conducted in an open field using a completely randomized design. The results indicated a significant impact of both hydrogel-type dose and water dose on onion plant growth, as evidenced by various vegetation parameters. Among the hydrogels tested, Huminsorb® Polyacrylate produced the most favorable outcomes, with treatment T9 (100%, HP, 30 kg/ha) yielding 70.55 t/ha; this represented an increase of 11 t/ha as compared to the 100% ETc treatment without hydrogel application. Moreover, the combination of hydrogel application with 50% ETc water stress showed promising results, with treatment T4 (HP, 30 kg, 50%) producing almost the same yield as the 100% ETc treatment without hydrogel while saving 208 mm of water.
In this article, we describe the structure, the functioning, and the tests of parabolic trough solar thermal cooker (PSTC). This oven is designed to meet the needs of rural residents, including Urban, which requires stable cooking temperatures above 200 °C. The cooking by this cooker is based on the concentration of the sun's rays on a glass vacuum tube and heating of the oil circulate in a big tube, located inside the glass tube. Through two small tubes, associated with large tube, the heated oil, rise and heats the pot of cooking pot containing the food to be cooked (capacity of 5 kg). This cooker is designed in Germany and extensively tested in Morocco for use by the inhabitants who use wood from forests.
During a sunny day, having a maximum solar radiation around 720 W/m2 and temperature ambient around 26 °C, maximum temperatures recorded of the small tube, the large tube and the center of the pot are respectively: 370 °C, 270 °C and 260 °C. The cooking process with food at high (fries, ..), we show that the cooking oil temperature rises to 200 °C, after 1 h of heating, the cooking is done at a temperature of 120 °C for 20 min. These temperatures are practically stable following variations and decreases in the intensity of irradiance during the day. The comparison of these results with those of the literature shows an improvement of 30–50 % on the maximum value of the temperature with a heat storage that could reach 60 min of autonomy. All the results obtained show the good functioning of the PSTC and the feasibility of cooking food at high temperature (>200 °C).