Search results for "Mechanical Properties"
showing 9 items of 199 documents
Polimeryzacja koordynacyjna alkenylosilseskwioksanów i ich kopolimeryzacja z olefinami lub styrenem
2015
Artykuł stanowi kontynuację przeglądu literatury dotyczącej koordynacyjnej polimeryzacji silseskwioksanów (POSS), zawierających zdolne do polimeryzacji wiązanie podwójne, oraz ich kopolimeryzacji głównie zolefinami, a także ze styrenem. Zastosowanie katalizatorów metalocenowych aktywowanych metyloaluminoksanem (MAO) zapewnia efektywną (ko)polimeryzację silseskwioksanów zarówno z olefinami, jak i styrenem. Wprowadzenie do materiału polimerowego komonomeru POSS korzystnie wpływa na właściwości otrzymanych produktów, które cechują się większą odpornością termiczną oraz wytrzymałością mechaniczną niż ich odpowiedniki niezawierające POSS.
On the effectiveness of different additives and concentrations on the re-building of the molecular structure of degraded polyethylene
2006
Mechanical recycling is an easy and economic way to re-use plastic waste as secondary materials, but, in general, their properties are worse with respect to the reclaimed materials and the virgin polymer. The aim of this work was to study the effect of concentration and reaction kinetics of two additives, an ethylene-co-glycidyl methacrylate (Lotader) and a hydroxylamine derivative (CGX), in the re-building of a degraded polyethylene. CGX is a nitroxyl radical generator able to form branching in polyolefins while the epoxy groups of Lotader can react with the functional groups present in the recycled polyethylene. The results indicate that the CGX has a higher reaction rate than Lotader, pr…
Functional Bionanocomposite Fibers of Chitosan Filled with Cellulose Nanofibers Obtained by Gel Spinning
2021
Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the gr…
Effect of Oxidized Potato Starch on the Physicochemical Properties of Soy Protein Isolate-Based Edible Films
2013
The influence of oxidized starch on the physicochemical properties of cast soy protein isolate films is determined in this study. Films were cast from heated (70 °C for 20 min) alkaline (pH=10) aqueous solutions of 7 % soy protein isolate containing 50 % (by mass) glycerol as a plasticizer and different levels of added oxidized starch (0, 5, 10, 15, and 20 %, by mass). For all types of films, opacity, contact angle, tensile strength, elongation at break, water vapour permeability, measured at 25 °C for four relative humidity differentials (30–53, 30–75, 30–84 and 30–100 %), differential scanning calorimetry and microstructure were determined after conditioning film specimens at 25 °C and 30…
Kenaf-filled biodegradable composites: rheological and mechanical behaviour
2012
Local mechanical properties by Atomic Force Microscopy nanoindentations
2008
The analysis of mechanical properties on a nanometer scale is a useful tool for combining information concerning texture organization obtained by microscopy with the properties of individual components- Moreover, this technique promotes the understanding of the hierarchical arrangement in complex natural materials as well in the case of simpler morphologies arising from industrial processes. Atomic Force Microscopy, AFM, can bridge morphological information, obtained with outstanding resolution, to local mechanical properties. When performing an AFM nanoindentation, the rough force curve, i.e., the plot of the voltage output from the photodiode vs. the voltage applied to the piezo-scanner, …
Statistical analysis of the relation between metallic microstructures and mechanical properties
2020
This thesis aims at the development of physical relations between the intricate 3D features of metallic microstructures and the mechanical properties of the material. For understanding which are the microstructural determinants of the resultingmechanical behaviour of metals, a deep quantitative characterisation of the microstructure is needed. The main steps of quantitative characterisation of the microstructures are: identification of the phases distribution and their chemical composition, study of the microstructure morphology (geometrical arrangement of grains, grain boundaries, grain orientations, grain size and grain shape). An accurate description of the microstructure features enrich…
Artichoke fibres as potential reinforcement of composite materials: mechanical and thermal characterization
2011
Environmental Effects on Mechanical, Thermophysical and Electrical Properties of Epoxy Resin Filled with Carbon Nanofillers
2019
The aim of this work was to establish the effect of environmental factors (moisture and temperature) on some mechanical, electrical and thermal properties of epoxy-based composites filled with carbon nanofillers: nanotubes (CNT), nanofibers (CNF) and hybrid nanofiller (nanotubes/nanofibers in the ratio 1:1) and to reveal the most environmentally stable NC. First, the nanocomposites (NC) containing different nanofiller contents were prepared to evaluate electrical percolation threshold and to choose NC at certain electrical conductivity for further characterization of the physical properties in initial state and during/after environmental ageing. The environmental ageing consisted of water a…