Steuerung funktioneller Materialeigenschaften eines Polybenzoxazin-Netzwerks über die Integration von Poly(caprolacton)-Oligomeren

The present dissertation deals with the specific control of the functional properties of a bisphenol A based polybenzoxazine (PBA-a). Therefore, the thermoset was combined with the thermoplastic oligomer poly(caprolactone) (PCL). The influence of covalently integrated versus unbound PCL on polybenzoxazines properties was the main focus of this cumulative work and for that reason systematically analyzed by varying the PCL content in the polymer mixtures. The polyester end groups were functionally modified with a tosyl leaving group. In contrast to the hydroxy-terminated basic structure, the modified PCL could be covalently integrated into benzoxazines network. The copolymers homogeneous morphology observed by scanning electron micrographs of PCL/PBA-a revealed that the covalent incorporation of the polyester chains could prevent phase separation of the components as occurred for the unmodified PCL/PBA-a blend-like structures. A slightly decreased network density, due to the incorporated PCL chains, reduced the brittleness of samples with low contents of modified PCL (wPCL 30 %). Thus, toughness values of up to 1.66 MPa were achieved compared to 0.48 MPa for neat PBA-a. By increasing the content of the tosylated PCL in the samples (wPCL = 30 - 50 %) network density was lowered accordingly, resulting highly flexibilized polymers with an almost 10 times increased elongation at break compared to PBA-a. Due to the macroscopic phase separation, a further increase of the amount of unmodified PCL led to samples with even higher brittleness. Polymers with high levels of tosyl-modified PCL (wPCL = 60 - 80 %) exhibited thermoresponsive shape memory properties, which could be attributed to the presence of both covalently incorporated and free PCL in these samples with mixed bonding mode. The combination of the widened network and increased crystallinity are key factors to the displayed shape memory effect. In this work, benzoxazine networks with variable and functional properties have been successfully prepared due to the covalent integration of PCL oligomers. The deeper understanding of the structure-property relationship will facilitate a broader application of polybenzoxazine based materials

Digital Twins of Business Processes as Enablers for IT / OT Integration

The vision of Industry 4.0 introduces new requirements to Operational Technology (OT) systems. Solutions for these requirements already exist in the Information Technology (IT) world, however, due to the different characteristics of both worlds, these solutions often cannot be directly used in the world of OT. We therefore propose an Industrial Business Process Twin (IBPT), allowing to apply methods of one world to another not directly but, instead, to a representation, that is in bidirectional exchange with the other world. The proposed IBPT entity acts as an intermediary, decoupling the worlds of IT and OT, thus allowing for an integration of IT and OT components of different manufacturers and platforms. Using this approach, we demonstrate the four essential Industry 4.0 design principles information transparency, technical assistance, interconnection and decentralized decisions based on the gamified Industry 4.0 scenario of playing the game of Nine Men's Morris. This scenario serves well for agent based Artificial Intelligence (AI)-research and education. We develop an Open Platform Communications Unified Architecture (OPC UA) information and communication model and then evaluate the IBPT component with respect to the different views of the Reference Architecture Model Industry 4.0 (RAMI4.0).Comment: Submitted to INDIN2023 conferenc

Highly Crosslinked Polybenzoxazines from Monobenzoxazines : The Effect of Meta-Substitution in the Phenol Ring

It is possible to control the crosslink density of polymers derived from monobenzoxazines by switching the type of substituents in the phenolic ring and their relative position with respect to the phenol group. We prepared several substituted monobenzoxazines in the para and meta positions of the phenolic ring and studied how these substituents affected the polymerization temperature of monomers and the thermal stability of the final polymers and, more extensively, how they affected the crosslink network of the final polymers. Gel content and dynamic mechanical analysis confirm that ortho- and para-orienting substituents in the meta position generate highly crosslinked materials compared to para ones. This fact can lead to the design of materials with highly crosslinked networks based on monobenzoxazines, simpler and more versatile monomers than the commercial bisbenzoxazines currently in use

The ferroelectric photo ground state of SrTiO3: Cavity materials engineering

Optical cavities confine light on a small region in space, which can result in a strong coupling of light with materials inside the cavity. This gives rise to new states where quantum fluctuations of light and matter can alter the properties of the material altogether. Here we demonstrate, based on first-principles calculations, that such light-matter coupling induces a change of the collective phase from quantum paraelectric to ferroelectric in the SrTiO3 ground state, which has thus far only been achieved in outof-equilibrium strongly excited conditions [X. Li et al., Science 364, 1079-1082 (2019) and T. F. Nova, A. S. Disa, M. Fechner, A. Cavalleri, Science 364, 1075-1079 (2019)]. This is a light-matter hybrid ground state which can only exist because of the coupling to the vacuum fluctuations of light, a photo ground state. The phase transition is accompanied by changes in the crystal structure, showing that fundamental ground state properties of materials can be controlled via strong light-matter coupling. Such a control of quantum states enables the tailoring of materials properties or even the design of novel materials purely by exposing them to confined light.We are grateful for the illuminating discussions with Dmitri Basov, Atac Imamoglu, Jerome Faist, Jean-Marc Triscone, Peter Littlewood, Andrew Millis, Michael Ruggenthaler, Michael A. Sentef, and Eugene Demler. We acknowledge financial support from the European Research Council (Grant ERC2015AdG694097) , Grupos Consolidados (Grant IT124919) , the Japan Society for the Promotion of Science KAKENHI program (Grant JP20K14382) , and the Cluster of Excellence "CUI: Advanced Imag-ing of Matter" of the Deutsche Forschungsgemeinschaft (Grant EXC 2056 Project 390715994) . The Flatiron Institute is a division of the Simons Foundation. S.L. and D.S. acknowledge support from the Alexander von Humboldt Foundation

Laparoscopic mesh-augmented hiatoplasty without fundoplication as a method to treat large hiatal hernias

PURPOSE: Laparoscopic hiatal hernia repair with additional fundoplication is a commonly recommended standard surgical treatment for symptomatic large hiatal hernias with paraesophageal involvement (PEH). However, due to the risk of persistent side effects, this method remains controversial. Laparoscopic mesh-augmented hiatoplasty without fundoplication (LMAH), which combines hiatal repair and mesh reinforcement, might therefore be an alternative. METHODS: In this retrospective study of 55 (25 male, 30 female) consecutive PEH patients, the perioperative course and symptomatic outcomes were analyzed after a mean follow-up of 72 months. RESULTS: The mean DeMeester symptom score decreased from 5.1 to 1.8 (P < 0.001) and the gas bloating value decreased from 1.2 to 0.5 (P = 0.001). The dysphagia value was 0.7 before surgery and 0.6 (P = 0.379) after surgery. The majority of the patients were able to belch and vomit (96 and 92 %, respectively). Acid-suppressive therapy on a regular basis was discontinued in 68 % of patients. In 4 % of patients, reoperation was necessary due to recurrent or persistent reflux. A mesh-related stenosis that required endoscopic dilatation occurred in 2 % of patients. CONCLUSIONS: LMAH is feasible, safe and provides an anti-reflux effect, even without fundoplication. As operation-related side effects seem to be rare, LMAH is a potential treatment option for large hiatal hernias with paraesophageal involvement