Dielectric, flammability and physico-chemical properties of surface functionalized Cannabis indica fibers reinforced composite materials

2015 ◽  
Vol 57 (2) ◽  
pp. 221-232 ◽  
Author(s):  
Ashvinder K. Rana ◽  
Amar S. Singha
2020 ◽  
Vol 4 (2) ◽  
pp. 42 ◽  
Author(s):  
Ignazio Blanco

Nowadays, all production, from the smallest ones to large companies, and research activities are affected by the use of 3D printing technology. The major limitation, in order to cover as many fields of application as possible, is represented by the set of 3D printable materials and their limited spectrum of physico-chemical properties. To expand this spectrum and employ the 3D-printed objects in areas such as biomedical, mechanical, electronical and so on, the introduction of fibers or particles in a polymer matrix has been widely studied and applied. In this review, all those studies that proposed modified polymer presenting advantages associated with rapid prototyping are reported.


2016 ◽  
Vol 87 (10) ◽  
pp. 1192-1202 ◽  
Author(s):  
Toty Onggar ◽  
Gosbert Amrhein ◽  
Anwar Abdkader ◽  
Rolf-Dieter Hund ◽  
Chokri Cherif

High-performance yarns such as aramid fibers are nowadays used to reinforce composite materials due to their advantageous physico-chemical properties and their low weight. They are also resistant to heat and fire. Para-aramid filament yarns (p-AFs) wound on a cylindrical dyeing package have been silvered successfully by means of a newly developed wet-chemical filament yarn metallization process on a laboratory scale. The surface morphology of untreated and silvered p-AF was determined by means of scanning electron microscopy. The chemical structure of the surfaces (contents of carbon, oxygen, nitrogen and silver) was determined by means of energy-dispersive X-ray spectroscopy (EDX). The eliminated and newly formed groups of p-AF before and after silvering were detected by infrared spectroscopy (Fourier transform—attenuated total reflectance). After metallization, the silver layer thickness, the mass-related silver content and washing and rubbing fastness were assessed. Furthermore, textile-physical examinations concerning Young's modulus, elongation at break and electrical conductivity were performed. Subsequently, the electrically conductive p-AFs were integrated in thermoset composite materials reinforced by glass fibers and para-aramid.


2015 ◽  
Vol 789-790 ◽  
pp. 1171-1175
Author(s):  
Saniye Karaman Öztaş

Composite materials are made from two or more constituent materials with significantly different physical or chemical properties. The materials work together to give the composite more excellent properties than its components.Fiber reinforced composite materials constitute a widely used group of the composites. There are many researches about fiber reinforced composites. This study focused on fiber reinforced composite materials used in architecture unlike other researches. It was aimed to specify the benefits of the fiber composite materials for architecture and discussed several recent developments related to these materials. A literature review was made by grouping composites materials. The study reported that more research is needed for fiber reinforced composites to improve their technical performance, environmental and economic properties.


2020 ◽  
pp. 26-29
Author(s):  
Y. M. Yevtushenko ◽  
Y. A. Grigoriev ◽  
I. O. Kuchkina ◽  
E. V. Afoshina ◽  
G. A. Krushevsky

A brief review of the results of studies on reducing the combustibility of composite materials based on unsaturated polyester resins is presented. A flame retardant orthophthalic unsaturated resin based on a complex flame retardant was developed and studied. It is shown that the category for resistance to burning of the resin is achieved with 15–20% filling of the complex flame retardant based on ammonium polyphosphate, melamine and pentaerythritol. The kinetics of curing and physical and mechanical properties of the composite material are evaluated.


Author(s):  
H. Gross ◽  
H. Moor

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.


1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)


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