In the presented work the influence of different 3MgO·4SiO2·H2O (talc) contents in polypropylene samples on the structure, hardness, elasticity, and friction of the surface layer was investigated. The talc content ranged from 0 to 25 wt.%, and all the samples were obtained in the same conditions by the injection molding process. The analysis of the microstructure was performed by X-ray diffraction. Changes in the hardness and elasticity were determined for three different depths (300, 800, and 4000 nm) using an ultra nano tester. For the purpose of the examination of the friction properties of the obtained compounds, a nano-scratch tester was applied. Increasing the talc content caused growth in the indentation modulus and hardness values. Simultaneously, an effect of decreasing hardness and elastic modulus with increasing indentation depth was observed. The smallest effect size was observed for 25 wt.% talc content, which might suggest that talc addition increased the homogeneity of the observed composites. Scratch tests showed increasing scratch resistance along with increasing talc content for both constant and progressive loads. The growth in talc concentration led to a decrease in the degree of the polypropylene (PP) crystallinity of the surface layer. The exfoliation process occurred in PP composites.
Evolution of stresses developing in Cu thin films during and after deposition by thermal evaporation in UHV system is studied. Thin films were deposited on 100 µm thick Si substrate at room temperature. Deposition rates for the films were changed between 0.2 Å/s and 2.0 Å/s, while the total thickness was changed from 7.7 nm to 155 nm. Deformation analysis of crystalline lattice and microstructure was performed by x-ray diffraction measurements (θ-2θ scans, "sin 2 ψ" method). The surface morphology of film was studied by atomic force microscopy. The average stress in the films was determined by measuring the radius of curvature of samples. For thin films three stages of stress evolution (compressive, tensile and compressive) were we distinguished. This behavior is characteristic for materials with a Volmer-Weber mode. A three-dimensional molecular dynamics technique was applied for simulating the stress calculation during thin film growth. The results obtained from the simulation are consistent with the experimental results.
Starch films modified with additives are materials increasingly being used in the production of packaging. These types of biopolymers can, to a considerable degree, replace plastic, contributing to the reduction in both production and waste management costs. However, they should be characterised by specific mechanical and surface parameters which determine their application. In the presented work, the PeakForce Quantitative Nanomechanics Mapping (PFQNM) method was applied to analyse a starch-based biopolymer modified with two different kaolin clay contents (5% and 10%). The technique used facilitates the assessment of the correlation of Atomic Force Microscope AFM height parameters with nanomechanical ones which provide the definitions of mutual interactions and allow the possibility to analyse materials in respect of various details. The investigated material was mapped in the Derjaguin–Muller–Toporov (DMT) modulus, adhesion and height domains. The results obtained indicated the impact of additives on the determined parameters. Increases in the DMT modulus and the adhesion force, along with the kaolin content, were observed. The enhancement of starch films with kaolin clay also induced growth in the surface roughness parameters.
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