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The substantial increase in the use of the FDM (Fused Deposition Modeling) process for the production of plastic parts in ever wider fields has led to the search for methods to improve the quality of the printed parts. In the case of ABS parts (Acrylonitrile Butadiene Styrene), one of the most common and used methods to improve surface quality is the process of acetone steam treatment, but the application of this method also brings more or less negative effects on the part. The main side effects when applying this method is the low breaking strength and loss of part details on the sharp edges. This paper presents a set of contributions on the relationship between surface quality and the level of detail of parts subjected to acetone steam treatment. In order to analyze the influence of the treatment on the details of the parts, a reverse engineering method was used in which a polyarticular arm FARO Edge 7.5 was used to scan the parts and reconstruct them. The study was performed on parts with 20% infill, grid tipe.

With the fourth industrial revolution, Additive Manufacturing started to offer new possibilities of manufacturing, Fused Deposition Modeling being one of the most used processes for fabrication. In this paper, the studied specimens are manufactured based on the Fused Deposition Modeling (FDM) method, with a filament of short carbon fiber and polyethylene terephthalate (PET) matrix, with a variation of the layer thickness. For the resulted specimens the tensile properties are determined according to ASTM D638. The most advantageous results are obtained for the layer thickness of 0.15 mm, with the tensile strength of 58 MPa. Based on the stress-strain curves which are presented in this paper, it also can be assumed that the material is brittle. The results of the mechanical properties are very similar for each group of specimens and it can be assumed that the mechanical properties are homogenous due to the material quality and the machine performances. For all the specimens the rupture location is almost in the same area. Due to the difficulty of carbon fiber filament printing, the manufacturing defectives which appear during the manufacturing process are detected, the most common manufacturing defectives being the material gaps from each specimen, which are identified with microstructural analysis. As failure modes, the most common failure criteria are the delamination and the matrix cracks.

An innovative recycling process for thermoset composite laminates is proposed by thermo-mechanical disassembly and further compression molding of hybrid thermoformable composite plates. Due to the thermo-mechanical process, single cured plies are extracted from the waste laminate. Subsequently re-lamination is performed by interposing thermoplastic films between the reclaimed composite plies. Final consolidation is carried out by compression molding. In order to show the feasibility of the novel recycling technology, carbon fiber reinforced composite plates by autoclave molding were thermo-mechanically disassembled in a manual roll bending machine after heating in oven. Reclaimed cured plies were laminated by alternating thermoplastic interlayers made of low density polyethylene. The hybrid laminate was consolidated at the temperature of 220°C and the holding pressure of 38.5 bar. Results from bending tests on virgin and recycled plates showed the very good agglomeration of the hybrid samples and the optimal preservation of performances of initial cured plies of the virgin material into the recycled plate.

Results on mechanical properties of Tensylon® composites at room temperature are presented. Single-ply and two-ply samples, obtained from the ply-precursor sheet (of two orthogonal layers) have been subjected to: load till failure in traction, at different strain rates (below 10-1 s-1) and cycles of successive loading and unloading and 5 min stress relaxation period. The characteristic times of relaxation are evaluated and the difference in values of Young modulus before and after the relaxation stage is established. A complex cyclic/relaxation test requires a visco-elasto-plastic model of Tensylon®, and allows to quantify it. This model predicts the material behavior in other types of tests: for instance, it predicts strain rate independence of loading to failure in the considered strain rate range. Cyclic tests fulfilled at a fixed strain rate suggest that Tensylon® is an elastoplastic material without noticeable viscosity. The proposed model, additively including nonlinear viscoelasticity and plastic flow with strengthening, shows a satisfactory agreement with experimental data. It also agrees that the material is strain-rate-insensitive in the range 10-3 s-1–10-1 s-1.

Several phenylazophenoxyacetic acid derivatives were obtained starting from azophenols and ethyl chloroacetate by an environmentally friendly approach. The synthesis reaction was carried out in heterogeneous medium using P(AAm-co-DADMAC) copolymer. Good results have been obtained thanks to phase transfer catalysis. Retrosynthetic and structural analysis were performed.

In the recent past, the demand for multifunctional and lightweight materials have increased steadily creating an increase in demand for Hybrid polymer matrix composite which consists multiple fibers in conventional resins. In this study, a hybrid composite comprising of two reinforcements - natural silk fiber and E-Glass fiber - in an Epoxy resin matrix which is a partially eco-friendly composite has been fabricated and the effect of drilling, by using an 8 facet solid carbide drill, on the surface roughness has been studied. Taguchi’s L27 Orthogonal array was used for experimentation by modifying three parameters - feed rate, spindle speed and drill diameter - on three levels (low, medium and high) and thereby studying the effects. From the results of experimentation it has been observed that increase in spindle speed and drill diameter reduces surface roughness however it increases with increase in feed rate. Further, regression analysis and Fuzzy modeling are used in order to determine optimum parameter values to get the desired surface finish. Good agreement between the experimental, regression and fuzzy model is observed with the correlation coefficient of 0.9814 and 0.9677 respectively.

At the beginning of the 90`s on the market of dental restoration materials appeared compomers, polyacid modified composite resins (PMC). The term compomer suggests a combination of glass-ionomer and composite technology. This has led to confusion about how it relates to dental structures. The properties and adhesion of compomers to dental structures suggest a closer connection with composites than with glass ionomers. They do not have direct chemical adhesion to any tooth structure it adheres similar to the composites through a separate binding agent. However, their proximity to composites does not make them substitutes of composites. Compomers are a versatile class of dental restorative biomaterials, whose clinical benefits are particularly useful in pediatric dentistry.

Infections that occur after the insertion of biomedical devices are a major problem; potential sources of infection are due to the adhesion of bacteria on the surface of implants, bacteria that form biofilms. In order to combat or to effectively prevent various microbial, which occur in medical procedures, we try to make compounds and materials that prevent the formation or development of microbial biofilm. The aim of this study was to obtain nanostructured surfaces based on magnetite, carboxymethylcellulose and ceftriaxone, as films with anti-infective properties in order to use them in the field of current biomedicine. To obtain nanostructured surfaces with high non-stick potential, the carboxymethylcellulose-functionalized magnetite powder was homogenized with an anti-infective agent, ceftriaxone. From the analysis of the obtained results it was found that the nanostructured surfaces obtained had a strong antimicrobial character infections and can be used successfully in the coating of medical implants, in order to combat the microbial biofilm.

The objective of this study is to demonstrate how the effect of adding multi-walled carbon nanotubes (MWCNTs) nanoparticles to the (Hydroxyapatite /High-density polyethylene) bio-composites. In this investigation, the samples with various percentages of (MWCNTs) were fabricated by a hot-press technique. The morphological characteristics, roughness of the surface and thermal properties of the bio-composite samples (HA/HDPE/MWCNTs) were investigated. The excellent homo-geneous distribution of the internal fibrous network and microstructure arrangements were among the most prominent characteristics obtained through FE-SEM and AFM examinations. The degree of crystallinity showed that the (MWCNTs) additives enhance by an increase of approximately (35%), compared with pure sample (without addition MWCNTs). Based on the experimental results obtained, the fabrication of the presented bio-composites sample exhibited the excellent characteristics that make them promising material for biomedical application as a substitute material for hard tissue likes bone reconstruction.

In this work an attempt had been made to hybridise the Epoxy resin by incorporating the Pterocarpus Marsupium natural resin powder derived from the Pterocarpus Marsupium tree. The mechanical, dynamic mechanical, biodegradability and thermal stability of the blended polymer was evaluated at different Pterocarpus Marsupium resin particulate loading (10, 15, 20, 25, 30 and 35 v/v %). The composite specimens were fabricated by using hand layup method. The mechanical properties such as tensile strength, flexural strength had shown significant improvement than the tensile modulus and flexural modulus due to blending, the experimental results indicated that the better properties of the blended polymer were obtained at 30% v/v Pterocarpus Marsupium resin incorporated Epoxy polymer. Soil burial test revealed that the incorporation of bio resin resulted in weight loss of the blended polymer over prolonged period of time.