1,721,135 research outputs found
Nano clay reinforced PCL/starch blends obtained by high energy ball milling
No full textSodium montmorillonite was incorporated into a poly(epsilon-caprolactone)–starch blend by means of a ball mill. The structural organization and physical (mechanical, thermal and barrier) properties were analyzed and correlated with the milling conditions. Scanning electron microscopy and X-ray characterization show that the milling process can improve the compatibilization between the PCL and the starch phases, while promotes the dispersion of clay minerals at nanometric level. The milling time strongly influences the mechanical and barrier properties. In particular, the best results in terms of elastic modulus and permeability coefficient were achieved with a complete delamination of the pristine clay structure. In summary, the milling process not only has demonstrated to be a promising compatibilization method for immiscible PCL–starch blends, but it can be also used to improve the dispersion of nanoparticles into the polymer blends
Correlations between microstructural characterization and thermal properties of well defined poly(epsilon-caprolactone) samples by ring opening polymerization with neutral and cationic bis(2,4,6-triisopropylphenyl)tin(IV) compounds
No full textElectro-curing: Saving Energy for the Manufacturing of Structural Resins is Possible
No full textThe development of structural thermosetting composites is now widely exploited in the transport field, allowing for simultaneously having structural properties and mass reduction. Their applicability presents several advantages, including a lower temperature for processing the materials than other structural materials (i.e., metals). For the transport sector, weight saving allows reducing CO2 emissions and energy consumption during the in-service vehicles. Different research papers have highlighted that the manufacturing process is one of the most critical phases for the environmental impact of composite production. Currently, the primary process for producing epoxy composites (curing in an autoclave) is energy, time-consuming, and hardly tunable. Moreover, it often causes, during the curing cycle, gradients of temperatures in the components that may lead to the generation of microcracks or stress concentration. In light of these premises, the present research aims to present an energy-saving and highly tunable alternative process realized through electro-curing. The fluid epoxy resin is filled with carbonaceous electrically conductive nanofillers (multi-wall carbon nanotubes) to obtain a conductive mixture to be electrically cured via the Joule effect, obtaining a final product with a curing degree higher than the samples cured in an oven and requiring less than 10% of the energy compared to the autoclave process. Using the electro-curing process, the necessary energy for curing the samples is directly generated inside the resin via the Joule effect. Moreover, the electro-curing is highly and rapidly tunable since the energy generated in the sample is strictly related to the applied voltage and, so, the applied power. In the present research paper, a multi-step electro-curing process has been pursued and compared to samples cured in an oven. These results make electro-curing a promising method for producing thermosetting composites due to the substantial reduction of the environmental impact
Infrared Investigation of Photodegradation of Polypropylene Filled with Multiwalled Carbon Nanotubes
No full textA preliminary evaluation by infrared spectroscopy of the photo-oxidative behavior of nanocomposites containing isotactic Polypropylene and MWCNT show that the carbon nanofillers are very effective in increasing the durability and service time of these materials.
Damping assessment of new multifunctional epoxy resin for aerospace structures
No full textThe increasing demand for more advanced materials, particularly in the aerospace field, has led to the development of carbon-fiber-reinforced composite manufactured employing different kinds of nanoparticles. The reinforcement with Carbon Nanotubes (CNTs) allows the modulation of several characteristics of the composite, which becomes suitable for more extreme operating conditions. Furthermore, the incorporation of CNTs in polymeric matrices of composite materials allows them to be electrically conductive, and hence suitable for developing self-responsive/self-protective materials characterized by a combination of properties strongly requested for replacing the traditional composites. In addition, detection of specific electrical properties can be used to develop self health-monitor composites subjected to damages due to static and dynamic loads. For instance, damage detection through conductivity measurements offers many advantages when compared to traditional glass fiber optic sensors. In fact, because of their high cost, it is not possible to create a dense network of these fibers to inspect large parts of the composite and especially if the damage spreads in the material without crossing the fiber. Therefore, the use of carbon nanotubes may provide an effective solution to overcome the described limitation. As part of an intensive research activity aimed at studying the performance of innovative smart resins, in this article, the authors show the outcomes related to some of the dynamic properties of the developed resins. Relevant results related to the enhancement of dissipative phenomena have been found in formulation modified with elastomeric phase e CNTs
PET and active coating based on a LDH nanofiller hosting p-hydroxybenzoate and food-grade zeolites: Evaluation of antimicrobial activity of packaging and shelf life of red meat
No full textEvaluation of zein/halloysite nano-containers as reservoirs of active molecules for packaging applications: Preparation and analysis of physical properties
No full textDYNAMIC PERFORMANCE OF A NANO-MODIFIED COMPOSITE AERONAUTICAL PANEL
No full textThe adoption of composite materials is becoming increasingly attractive in many aeronautical applications. The improved endurance and corrosion resistance are few of the advantages they can offer, compared to the conventional alloy solutions. Due to the extraordinary mechanical property of carbon nanotubes (CNTs), they can be considered as an effective reinforcement treatment for composites. Multifunctional materials are designed so as to meet specific requirements through tailored properties. These materials, employed both for general aviation and very light class, allow to be readily modified with extra upgrading treatments during the lay-up manufacturing phase, thanks to their physical constitution. Particularly, in aerospace applications, the potential implementations of these advanced materials have been predicted to have a large impact on future aircraft vehicles, mainly due to their distinct features, which include greater mechanical, thermal and electrical characteristics. In such framework, different vibro-acoustic tests have been performed on a fiber-reinforced panel, representative of an aeronautical shell, for the characterization of the damping as well as the transmission loss properties related to such micro-handling treatment. The spectral excitation has been provided by an acoustic source, simulating in such a way the aerodynamic pressure load agent on the structure. Significant studies have been carried out to investigate and improve the vibro-acoustic properties of filled or reinforced polymer composites: the authors showed that the use of nano-particles such as CNTs can really improve the dynamic performance of standard laminates
CURING MONITORING OF AN EPOXY/CARBON NANOTUBE COMPOSITE USING DC CONDUCTIVITY MEASUREMENTS
No full text- …
