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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.

The paper addresses the methodology for obtaining biocomposite structures from waste, with sound-absorbing properties, such as: thuja shells, walnut shells, pistachio shells, beech sawdust, pumpkin seeds shells and sunflower seeds shells. The experimental analysis carried out considers the study of the sound-absorbing properties held by the proposed new biocomposite materials, by determining the value of the sound absorption coefficient, reflection coefficient, impedance ratio, using the Kundt tube. The interpretation of the results obtained from the evaluation of biocomposites shows that they have sound-absorbing properties. Consequently, sound-absorbing panels with soundproofing properties can be made from these materials, which can be used in industry, transportation, construction, etc. as well as for decorative purposes in spaces such as cinemas, malls, spas, etc.

Compomers have emerged by modifying dental composites in an effort to combine their desired properties, namely their good aesthetics, with those of glass ionomer cements, namely their ability to release fluoride for a long time. While this combination of good aesthetics and fluoride release may seem to give compomers an advantage, their poor mechanical properties limit their use. The main components of the compomers are polymerizable dimethacrylate resins, such as urethane dimetha-crylate and TCB (a butantetracarboxylic acid reaction product) and hydroxyethyl methacrylate and ionizable glass fillers, such as fluorosilicate glass.

Otitis and middle ear disease present high morbidity rates in spite of current medical treatment, especially in the younger population. Otitis media with effusion (OME) is a chronic disease that is often found in school age children. Its evolution, recurrence, complications and resolution still present a challenge to otologists. For some time, middle ear ventilation tubes were used for this pathology, thus assuring proper middle ear ventilation and higher disease resolution rates. In the current paper, we investigate the connection between ventilation tube usage, the materials out of which they are made, the techniques involved and how these factors may influence disease resolution rates.