Mechanical properties of polymers at 4.2�K and their dependence on chemical structure and the conditions of physical structure formation

1976 ◽  
Vol 11 (5) ◽  
pp. 661-671 ◽  
Author(s):  
T. I. Sogolova ◽  
M. I. Demina
Keyword(s):  
Mechanical Properties ◽  
Structure Formation ◽  
Chemical Structure ◽  
Physical Structure

scholarly journals Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1801
Author(s):  
Rafał Oliwa ◽  
Joanna Ryszkowska ◽  
Mariusz Oleksy ◽  
Monika Auguścik-Królikowska ◽  
Małgorzata Gzik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Structure ◽  
Oxygen Index ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Ftir Analysis ◽  
Limiting Oxygen Index ◽  
Peak Heat Release Rate ◽  
Physical And Chemical ◽  
Scanning Electron

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this composite was characterized by the highest char yield (m600 = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.

Structure formation in a nitrogen-bearing steel under thermodeformation conditions and its relation to the mechanical properties

2014 ◽  
Vol 2014 (12) ◽  
pp. 968-975 ◽  
Author(s):  
V. A. Malyshevskii ◽  
G. Yu. Kalinin ◽  
O. V. Fomina ◽  
T. V. Vikhareva ◽  
A. A. Kruglova
Keyword(s):  
Mechanical Properties ◽  
Structure Formation ◽  
Bearing Steel

The changes of crosslink density of polyurethanes synthesised with using recycled component. Chemical structure and mechanical properties investigations

2018 ◽  
Vol 115 ◽  
pp. 41-48 ◽  
Author(s):  
Patrycja Jutrzenka Trzebiatowska ◽  
Arantzazu Santamaria Echart ◽  
Tamara Calvo Correas ◽  
Arantxa Eceiza ◽  
Janusz Datta
Keyword(s):  
Mechanical Properties ◽  
Crosslink Density ◽  
Chemical Structure

scholarly journals Bio-Based Packaging Materials Containing Substances Derived from Coffee and Tea Plants

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5719
Author(s):  
Olga Olejnik ◽  
Anna Masek
Keyword(s):  
Mechanical Properties ◽  
Caffeic Acid ◽  
Green Tea ◽  
Chemical Structure ◽  
Green Tea Extract ◽  
Packaging Materials ◽  
Scanning Calorimetry ◽  
Spectra Analysis ◽  
Tea Extract ◽  
The Impact

The aim of the research was to obtain intelligent and eco-friendly packaging materials by incorporating innovative additives of plant origin. For this purpose, natural substances, including green tea extract (polyphenon 60) and caffeic acid, were added to two types of biodegradable thermoplastics (Ingeo™ Biopolymer PLA 4043D and Bioplast GS 2189). The main techniques used to assess the impact of phytocompounds on materials’ thermal properties were differential scanning calorimetry (DSC) and thermogravimetry (TGA), which confirmed the improved resistance to thermo-oxidation. Moreover, in order to assess the activity of applied antioxidants, the samples were aged using a UV aging chamber and a weathering device, then retested in terms of dynamic mechanical properties (DMA), colour changing, Vicat softening temperature, and chemical structure, as studied using FT-IR spectra analysis. The results revealed that different types of aging did not cause significant differences in thermo-mechanical properties and chemical structure of the samples with natural antioxidants but induced colour changing. The obtained results indicate that polylactide (PLA) and Bioplast GS 2189, the plasticizer free thermoplastic biomaterial containing polylactide and starch (referred to as sPLA in the present article), both with added caffeic acid and green tea extract, can be applied as smart and eco-friendly packaging materials. The composites reveal better thermo-oxidative stability with reference to pure materials and are able to change colour as a result of the oxidation process, especially after UV exposure, providing information about the degree of material degradation.

Conceptual Approach to Development, Structure Formation and Hardening Micro-Alloyed by Steels for the Metallurgical Tool

2020 ◽  
Vol 299 ◽  
pp. 658-663
Author(s):  
S.E. Krylova ◽  
Sergey V. Gladkovskii ◽  
E.V. Romashkov
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Chemical Composition ◽  
Structure Formation ◽  
Structural Parameters ◽  
Structural Transformations ◽  
Conceptual Approach ◽  
Phase And Structural Transformations ◽  
Technological Cycle ◽  
Development Structure

The scientific bases for the development of rational compositions and methods for hardening a large-sized metallurgical tool from micro-alloyed steels are stated. Based on the generalization of the experimental data, the regularities of phase and structural transformations at various stages of the technological cycle are revealed; the relationships between structural parameters, chemical composition and mechanical properties have been studied and described.

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