Figure 7 shows the mechanical properties of PVA bionanocomposites reinforced with HNT, Cloisite 30B and NBC clays at different nanofiller contents. In general, the Tg values of PVA bionanocomposite films incorporating NBC and Cloisite 30B clays are much higher than those of PVA/HNT bionanocomposites.
Conclusions
Synergistic effect of halloysite and cellulose nanocrystals on the functional properties of PVA-based nanocomposites. Effects of carbon nanoreinforcements of various shapes on the mechanical properties of epoxy-based nanocomposites. Macromol.
Application of Adaptive Neuro-Fuzzy Inference System in Flammability Parameter Prediction
Introduction
An adaptive neuro-fuzzy inference system (ANFIS) was developed in the 1990s based on the principles of the Takagi-Sugeno fuzzy inference system [16]. It is a hybrid analytical method, that is, it combines the advantages of the neural network and the theory of fuzzy logical systems in its operation [17].
Experimental Methods 1. Material
O2,i=ωi=μAi(x)×μBi(x),i=1,2 (10) Normalization of the firing strengths obtained in the second layer takes place in layer 3. The hybrid optimization algorithm is an integration of the gradient descent and least squares method [21].
Results and Discussion 1. MCC Experimental Results
Similarly, Figures 12-15 provide a visual representation of the variations in the predicted data from the ANFIS and FFBPNN models. An attempt has been made in this study to predict the HRC and THR measured from the Method A procedure in the MCC experiment.
Development of Coffee Biochar Filler for the
Production of Electrical Conductive Reinforced Plastic
Materials and Methods
The ash content of coffee and carbon-based materials (biochars and CB) were evaluated using a static oven set at 550 or 800◦C for 6 hours, respectively. Coffee, biochars and CB were analyzed by FT-IR (Nicolet 5700, Thermoscientific, Waltham, USA) on attenuated total reflection (ATR) mode (Smartorbit, Thermoscientific) in the range of 500 to 4000 cm -1 . In this configuration, the inner diameter was slightly larger so that it was possible to force the copper rods into the Plexiglas cavity and allow the top rod to slide into the cylinder during the measurement.
In the case of composites, the Plexiglas cylinder was removed and the sample was placed between the aligned copper cylinders. Electrically insulating plates were placed between the conductive cylinders and the charging pads to ensure that the electrical signal passed through the sample.
Results
The electrical resistance of the powders or composites was measured at increasing loads (up to 1500 bar) applied by a hydraulic press (Specac Atlas Manual Hydraulic Press 15T). After closing the chamber, a pressure was applied with the aim of compressing the powder. Preliminary results are shown in Figure 8, showing the conductivity of the biochar powder (red line) and percolation curves of related composites.
The effect of process temperature on biochar properties was investigated and it was observed that further temperature increases improved the porous stability and conductivity of the material. Self-healing epoxy composites—Preparation and effect of the healer consisting of microencapsulated epoxy and latent hardener.
Durability Analysis of Formaldehyde/Solid Urban Waste Blends
Results and Discussion
This is due to the higher value of the density (ρ) of the panels, also reported in table 3. Mechanical test results the analysis of the compressive behavior indicates better performance of OF50_MF samples even after cyclic tests. Then, all the prepared samples were submitted to the boiling test according to UNI EN 1087-1.
However, the OF50_MF sample showed better stiffness retention compared to the OF70_LUF sample, in both tensile and bending tests. This result is due to a higher water content of the slurry before the curing process.
Conclusion
Therefore, a lower release can be achieved by lowering the water content of the mixtures before the curing process. Even after artificial weathering cyclic heating-cooling or boiling tests, the melamine-formaldehyde-based mixture showed a better retention of the initial mechanical properties. An innovative green process for the stabilization and valorization of organic fraction of municipal solid waste (OFMSW) part II: Optimization of the curing process.Appl.
An innovative IoT-oriented prototype platform for the management and valorisation of the organic fraction of municipal solid waste.Submit. Analysis of the Concentration and Formation Behavior of Naturally Occurring Formaldehyde Content in Food.Int.
A Review on the Flammability Properties of Carbon-Based Polymeric Composites
State-of-the-Art and Future Trends
Carbon Family Materials
The reduction in flammability of the polymer composite is mainly due to the formation of a network structure layer on the burning surface and, compared to nanoclay FR, this layer is effectively formed during the use of CNTs [7]. The synergy of phosphorus and silicon was enhanced by the effectiveness of the FR system. These can be used individually (graphene only) and in hybrid form (graphene with conventional FRs or inorganic nanofillers) to improve the flame retardancy of the polymer composites.
It was concluded that both the tensile and flexural modulus of the biocomposites were increased with an increase in the concentration of BC. In summary, improved flame retardancy of polymer composites using BC reinforcement is one of the best techniques considering both environmental sustainability and low cost.
Flammability Measuring Techniques
A few studies reported its effect on the flammability of various polymeric matrices (Table 1) Studies showed that the CB-filled composites not only exhibited good flame retardancy, but also the thermal stability was improved [74–76]. This synergistic effect of hybrid form of CB and CF has shown better flame retardancy in the PP matrix compared to the individual performance of CB and CF. The procedure involves preparing and exposing said sample of size 127×13×3 mm3 to a carefully controlled flame for 10 s.
If the sample continues to burn upon initial flame application, it is given no rating. In the case of flame retardant polymer compositions, the addition of FRs sometimes leads to predecomposition and thereby.
Conclusions and Scope for Future Research
Effect of graphene filler structure on electrical, thermal, mechanical and fire retardant properties of epoxy-graphene nanocomposites - An overview. Crit. Synergistic improvement of flame retardant properties of expandable graphite and multiwall carbon nanotube reinforced intumescent polyketone nanocomposites. Carbon. Effects of Expandable Graphite and Modified Ammonium Polyphosphate on the Flame Retardant and Mechanical Properties of Wood Flour Polypropylene Composites.Polym.
Biochar to the rescue: Balancing the combustion performance and mechanical properties of polypropylene composites. Polym. A geometrical effect of carbon nanomaterials on flame retardancy and mechanical properties of ethylene-vinyl acetate/magnesium hydroxide composites. Polymer.
A Review on Barrier Properties of Poly(Lactic Acid)/Clay Nanocomposites
PLA/Layered Silicate Nanocomposites
However, the degree of distribution of the clay layers and the morphology thus achieved in the polymer matrix (intercalation, exfoliation, mixed intercalation and exfoliation, aggregation, etc.) greatly influence the gas barrier properties. The polymer solution is then mixed with the clay suspension, where the polymer chains are intercalated/adsorbed on the surface of the platelets and form a clay-polymer complex. Most of the PLA/clay systems prepared by melt processing resulted in intercalation structures.
Melt processing of the nanoclay with PLA yielded fully exfoliated nanostructures when the epoxy content in the clay was high (about 0.36 mmol/g). During the polymerization reaction, polymeric chains are formed within the clay galleries which force delamination of the platelets in the matrix.
Barrier Performance
The nanocomposite films showed 48% improvement in oxygen barrier and 50% improvement in water vapor barrier properties compared to the neat PLA film. It was also found that the gas permeability decreased with decreasing kinetic diameter of the molecule: CO2(3.3 Å)>O2(3.46 Å)>N2(3.64 Å), i.e. the films showed the highest permeability to CO2 due to its relatively small size. The barrier properties of the nanocomposites were studied in terms of water uptake of the films.
91] used MMT clay modified with different organic modifiers (Table 1) and investigated the effect of modification and clay ratio on the barrier properties of PLA nanocomposites. Chowdhury [92] investigated the effect of clay aspect ratio and degree of dispersion on the barrier properties of PLA nanocomposites.
Mass Transfer in Polymers
At steady state, the permeate concentration is constant on both sides (inside the material only), c1 and c2 for high and low concentration, respectively, of the film. In the isostatic method (continuous flow method), one side of the film is exposed to a constant concentration of penetrant and zero concentration is maintained on the other side. An important factor affecting mass transfer in polymers is the free volume of the polymer.
Free volume holes are created due to Brownian motion and thermal perturbations of the polymer chains. The static free volume is independent of the thermal movements of the polymer chains and is related to the permeant solubility,S, while the dynamic free volume is due to the segmental movements of the chains and is related to the permeant diffusivity,D.
Modeling of Permeability of Polymer/Clay Nanocomposites
The average orientation is assumed to be at a certain angle to the direction of diffusion of the permeant molecules. In this model, platelets are assumed to have a rectangular shape with finite length (l) and thickness (w) and are uniformly dispersed in the polymer matrix with an orientation perpendicular to the diffusion direction. The underlying theory of the model is that the presence of impermeable platelets forces permeant molecules to follow a longer diffusion path by traversing around the platelets.
The main assumption in all the models discussed above is that the platelets are aligned perpendicular to the direction of diffusion and therefore tortuosity is maximal. However, Bharadwaj [121] described a case where platelets can be oriented at different angles (90°) to the direction of diffusion.
Model Validation for PLA/Clay Nanocomposites
The Nielsen rotation model was used to provide an accurate description of the experimental results for the relative permeability and diffusivity of the nanocomposites. However, the Cussler model was found to give a better prediction of the system compared to other models. Using S=1 (platelets perpendicular to the direction of diffusion) gave the same description of the system as the Nielsen model.
126] investigated the effect of clay platelet hydration on the barrier properties of PLA/OMMT nanocomposites. However, the Nielsen-Bharadwaj model was found to be the best model to fit the experimental data of relative oxygen permeability of PLA/OMMT nanocomposites.
Conclusions
Physical and mechanical properties of PLA, and their functions in widespread applications—A comprehensive review.Adv. Influence of crystallinity on gas barrier and mechanical properties of PLA food packaging films. Int. Characterization and mechanical properties of poly(lactic acid)/poly(-caprolactone)/organoclay nanocomposites prepared by melt composition.Polym.
How the shape of fillers influences the barrier properties of polymer/non-porous particle nanocomposites: an overview. Improvements in barrier properties of poly(lactic acid) films coated with chitosan or chitosan/clay nanocomposite.J.
