JOURNAL OF CHARACTERIZATION, Year 2021 Issue 3

Full-factorial Experimental Design for the Investigation of Tribological Properties of PP / TiO2-Clay Composites

Soner Savaşİmran Seyhan Latifler — 2026-07-16

In current study, titanium dioxide (TiO₂) and clay reinforced polypropylene (PP) composites were produced by using melt compounding method in a twin-screw extrusion machine. Composite pellets were then subjected to injection moulding by using a microinjection moulder. Tribological properties of the composites were investigated using a ball-on-disc tester. Tribo-tests were performed at ambient temperature and dry sliding conditions. Full-factorial experimental design was used to find the main factors on the tribological characteristics of the samples. Filler type, filler content, applied load and turning speed were studied as main factors. It was seen that the wear rate increases, and the coefficient of friction (CoF) decreases by increasing the load and turning speed. The wear rate and the CoF decrease by using clay instead of TiO₂, at the content of 5% (wt).

Investigation of Tribological and Mechanical Properties of Polymethylmethacrylate (PMMA)/Glass Fiber Composites Prepared by Melt Blending

Lemiye Atabek Savaş — 2026-07-16

In this study, mechanical and wear resistance properties of polymethylmethacrylate (PMMA) matrix composites containing glass fiber in different weight percentages (5-10-20-30%) were investigated. Melt blending method was preferred using a twin screw extruder in production, and injection molding was used in the production of test samples. The mechanical properties of the composites were investigated by 3-point bending and Shore D hardness measurements, and the wear properties were examined using a custom-made ball-on-disk dry sliding wear tester. Pure PMMA shaped under similar conditions was also used as a control sample in the same tests and the results of the mentioned tests were interpreted depending on the glass fiber concentration. The highest bending stress and modulus of elasticity values (121 MPa and 7354 MPa, respectively) were obtained with PM30 sample containing 30% glass fiber. Similarly, properties such as high hardness, low friction and low wear rate were observed in composites containing 20% and 30% glass fiber. This situation was associated with the increase in the glass fiber content, increasing the stiffness of the composite and also improving the fatigue wear resistance.

Determination of Principal Axes and Principal Mass Moments of Inertia when no Planes of Symmetry Exist

Teodor Todorov — 2026-07-16

In the current article the determination of principal axes and mass moments of inertia is considered. Some theoretical background is provided, but the practical application is emphasized via example.

Investigation of Contact Angle and Wettability Properties of Polypropylene/Poly(lactic acid) Blends Reinforced with Carbon Fiber and Elvaloy

Lemiye Atabek Savaş — 2026-07-16

The aim of this study is to examine the effects of carbon fiber and ethylene-butyl acrylate addition on the contact angle and surface energy properties of polypropylene (PP)/poly(lactic acid) (PLA) blends. When PLA is added to PP, it is possible to expect improvements in mechanical properties and potential uses for different applications. Processing at similar temperatures also enables their production by melt blending. Since PP has a nonpolar structure and PLA has a polar structure, the use of compatibilizers in production is preferred to improve the properties of the blends. It is also natural to expect an increase in mechanical properties with the addition of carbon fiber. Composites were produced by melt blending method using a twin-screw extruder. PP/PLA blends were adjusted to be 75-25% and 25-75% by weight. Carbon fiber was added to the blends at 5-10-20 and 30% by weight. Elvaloy was added to the composites as a compatibilizer at a concentration of 5 phr for all compositions. The aim of this study is to investigate the effects of compatibilizer and carbon fiber use on the surface energies and wettability properties of PP/PLA blends.

Surface Modification of PC and PMMA sheet for Enhanced Scratch Resistance

Şenay İskenderSerkan İşmar ,Atilla Evcin — 2026-07-16

POLICAM PMMA (polymethylmethacrylate) and polycarbonates (PC) sheet used in many sectors such as furniture, decoration, building materials, lighting have optical properties. They are thermoplastic polymer sheets with a maximum usage temperature of 80 ° C. Thermoplastic polymer with amorphous structure is quite transparent and has the closest permeability to glass. Its density is half the density of glass and it is light. Fabrication applications are very easy. It is preferred instead of glass. Surface scratches are seen in areas of use in the environments where it is exposed. Surface improvement applications can be made with functional coatings. Sol-gel method is one of the most widely used methods because it is easy and useful in functional coating of ceramic, glass and plastic surfaces. In this study, the sol gel method was preferred for coating PMMA and PC plate surfaces. The prepared functional coating is applied to PC and PMMA sheet surface in certain thicknesses by means of an applicator. The improvements seen on the plate surface after the coating has cured have been controlled. Surface scanning with SEM, anti-scratching of the surface with pencil hardness test, and permanent properties on the surface were determined by artificial aging.

SARS-CoV-2 and other coronaviruses: innovative approaches of advanced characterization based on large machines of physics

2026-07-16

The novel coronavirus SARS-CoV-2, the pathogen responsible for the rapidly growing outbreak of coronavirus disease (COVID-19), is causing widespread concerns and fear, due to its extremely high contagiousness and the potential risk of developing pneumonia. Global research efforts have been devoted to investigating the molecular mechanism of virus pathogenesis, in order to develop effective drugs or vaccines to tackle the on-going pandemic. Several experiments related to SARS-CoV-2 proteins or for testing potential drugs for the treatment of viral infections are currently being carried out. In the present review, innovative approaches for advanced characterization based on large machines of physics, making use of Synchrotron radiation and Neutron beams, are discussed.