Self-healing efficiency study of thermoset-thermoplastic polymer material

This study is focused on exploring intrinsic self-healing polymer material development, where the inclusion of thermoplastic additives into thermoset polymer material as healing agents. Intrinsic self-healing thermoset-thermoplastic development is involving the material formulation of thermoset liquid resin (Poly Bisphenol A-co-epichlorohydrin) and thermoplastic (polycaprolactone). The material formulation ratio is up to 30% polycaprolactone with respect to thermoset weight. The mixture is heated and stirred to saturate at 80°C before the hardener is added. The mixture is cured and further finishing as Charpy impact test specimen. The specimen is fractured and absorbed impact energy property characterised through the Charpy impact test. The heat treatment is then performed to trigger the self-healing reaction in the polymer. The self-healing efficiency of the thermoset thermoplastic is investigated based on the absorbed impact energy before and after the heat treatment. The 20% or higher thermoplastic concentration in the polymer caused the polymer to possess high self-healing efficiency and faster healing time as compared to the low thermoplastic concentration polymer. However, the high concentration polymer has a disadvantage on the overall structural strength instead. On the contrary, 10% to 15% thermoplastic composition will result in lower and slower self-healing performance but higher initial structural strength.

A General Model for the Ideal Chain Length Distributions of Polymers Made with Reversible Deactivation

Polymer molecular weight, or chain length distributions, are a core characteristic of a polymer system, with the distribution being intimately tied to the properties and performance of the polymer material....

COMPLEX GEOMETRIC EVALUATION OF POLYMER MATERIALS QUALITY

A computational technique of comparative evaluation of polymer material quality in a homogeneous set of samples according to a complex geometric criterion is proposed. Samples of physical and mechanical parameters of samples of industrial impact-resistant polystyrene are used for calculation. The most averaged complex of physical and mechanical properties is used as the calculation base.

Annealing of Polymer Material PLA for Improved Properties

The aim of the work was to improve the properties of 3D printed products using annealing. The biggest problem that 3D printed products face is internal stress and poor tribological properties, but it can be eliminated by annealing. The material chosen for this work is PLA, which is the most used material for 3D printing. Stress reduction was performed by drying furnace, which is capable of gradually increasing the temperature and therefore does not cause unwanted thermal shock. The drying furnace is fully sufficient for annealing plastics as it is able to maintain temperatures up to 250°C. After annealing, the samples were placed into a UV chamber. With the help of heat and moisture, the deformation of annealed and non-annealed testing bodies was monitored.

Fabrication of Micro-Groove on the Surface of CFRP to Enhance the Connection Strength of Composite Part

Carbon fiber-reinforced plastic (CFRP) has the advantages of being light weight, high strength, and corrosion resistant. At present, it is widely used in the lightweight design of automobile parts. The manufacturing of lightweight parts inevitably involves the connection between CFRP and the polymer material. The connection strength between CFRP and the polymer material significantly affects the service life of the composite parts. Taking CFRP and polyamide 6 (PA6) injection-molded composite parts as an example, this paper proposed a technological method to enhance the connection strength between CFRP and PA6. The proposed method was to fabricate micro-groove structures on the CFRP surface by compression molding. These micro-groove structures effectively increased the injection-molding area of the composite parts, thus enhancing the connection strength between CFRP and PA6. This paper presented a detailed study on the compression-molding process of micro-grooves on the CFRP surface, and successfully obtained the appropriate parameters. Finally, PA6 was used for injection molding on the CFRP with micro-grooves at an injection pressure of 8 MPa, an injection temperature of 240 °C, a holding pressure of 5 MPa, and a holding time of 2.5 s. The experimental results show that the micro-groove array structures on the CFRP surface could effectively improve the tensile strength of the connection interface in the composite parts. Compared with the composite part without micro-grooves, the tensile strength of the composite part with micro-grooves was increased by 80.93%. The composite parts prepared in this paper are mainly used in automobile interiors and the research results of this paper meet the actual needs of the enterprise.

Analytical models for adiabatic compressed air energy storage (A-CAES) systems in lined tunnels

Adiabatic compressed air energy storage (A-CAES) systems consist of an underground reservoir where compressed air is stored at high pressures. The ambient air is compressed by compressors located at the surface and the thermal energy is stored using thermal energy storage (TES) systems. The compressed air is stored in the subsurface reservoir (charge). Then, when the electricity is needed, the compressed air is released and expanded in gas turbines to produce electricity (discharge). In this paper, an analytical model has been developed to investigate the thermodynamic behaviour during air charge and discharge processes. Operating pressures from 4.5 to 7.5 MPa has been employed in lined tunnels in the compression and decompression stages. The model considers a 20 mm thick sealing layer, a 0.4 m thick concrete lining and a 1 m thick rock mass around the air. Air mass flow rates of 0.19 and 0.27 kg s−1 have been used in the charge processes for polymer material and steel, respectively. Finally, in the discharge processes the mass flow rate increases up to -0.38 and -0.45 kg s−1 for polymer and steel. The air temperature and pressure and the temperature and heat transfer in the sealing layer, concrete lining and rock mass have been analyzed for 100 cycles considering polymer material and steel as sealing layers. The heat transfer through the sealing layer reaches -150 and -95 W m-2 for steel and polymer, respectively. The results obtained show that the storage capacity increases when the heat transfer through the sealing layer increases.

Preparation of Polymeric Nanomaterials Using Emulsion Polymerization

Nanoparticles are said to be active particles which are entrapped in the surface of the polymeric core. Since nanoparticles were used in medical and biotechnological fields, there is a great demand in the preparation of nanoparticles. Nanoparticles are prepared from different substances; mainly, polymer material is used in the field of preparing nanomaterials. There are different methods involved in the preparation of nanoparticles from the polymer. Various experiments and research studies were carried out on the basic preparation of nanoparticles. Emulsion polymerization could be used to make polymeric nanoparticles with a high solid concentration without the need of surfactants. To make carboxylate polystyrene beads or amidine polystyrene nanoparticles, polymeric nanocolloids containing surface functional groups were produced. In this research, the preparation of nanoparticles from emulsion polymerization is represented along with the size and distribution material.

Impact-Resistant and Tough 3D Helicoidally Architected Polymer Composites Enabling Next-Generation Lightweight Silicon Photovoltaics Module Design and Technology

Lightweight photovoltaics (PV) modules are important for certain segments of the renewable energy markets—such as exhibition halls, factories, supermarkets, farms, etc. However, lightweight silicon-based PV modules have their own set of technical challenges or concerns. One of them, which is the subject of this paper, is the lack of impact resistance, especially against hailstorms in deep winter in countries with four seasons. Even if the front sheet can be made sufficiently strong and impact-resistant, the silicon cells inside remain fragile and very prone to impact loading. This leads to cracks that significantly degrade performance (output power) over time. A 3D helicoidally architected fiber-based polymer composite has recently been found to exhibit excellent impact resistance, inspired by the multi-hierarchical internal structures of the mantis shrimp’s dactyl clubs. In previous work, our group demonstrated that via electrospinning-based additive manufacturing methodologies, weak polymer material constituents could be made to exhibit significantly improved toughness and impact properties. In this study, we demonstrate the use of 3D architected fiber-based polymer composites to protect the silicon solar cells by absorbing impact energy. The absorbed energy is equivalent to the energy that would impact the solar cells during hailstorms. We have shown that silicon cells placed under such 3D architected polymer layers break at substantially higher impact load/energy (compared to those placed under standard PV encapsulation polymer material). This could lead to the development of novel PV encapsulant materials for the next generation of lightweight PV modules and technology with excellent impact resistance.

Preparation of a Composite Material by Graft Copolymerization of Methylmethacrylate and Fish Gelatin Using a Photocatalyst - Complex Oxide RbTe1.5W0.5O6

A new composite material based on fish gelatin (FG) was obtained by graft copolymerization of methylmethacrylate (MMA) onto fish gelatin. The process was initiated by radicals formed by the RbTe1.5W0.5O6 photocatalyst under visible light (λ=400-700 nm) irradiation at room temperature. The characteristics of the new polymer material were obtained by the methods of elemental and physico-chemical analyses.