scholarly journals Polymeric Geomembranes Used in Municipal Waste Facilities

2020 ◽  
Vol 57 (3) ◽  
pp. 117-124
Author(s):  
Doru Mihai ◽  
Narcisa Elena Pogurschi ◽  
Nicoleta Daniela Sarbu ◽  
Constanta Valentina Tudor ◽  
Adina Horablaga ◽  
...  
Keyword(s):  
Crosslinking Density ◽  
Municipal Waste ◽  
Degree Of Crystallinity ◽  
Household Waste ◽  
Cement Stone ◽  
Microporous Material ◽  
Ongoing Research ◽  
Microbiological Pollutants ◽  
And Diffusion ◽  
The Degree Of Crystallinity

This research aims to establish the behaviour of geomembranes used for base sealing and for covering municipal waste facilities. The geomembranes used for base sealing are subjected to leachate pressure and to the action of chemical and microbiological pollutants. Geomembranes used for covering waste facilities are subjected to the action of precipitation water and released gases. This paper analyzes the following: the permeability mechanism of geomembranes made of polymers, the process of water vapours diffusion through polymers, diffusion flow, characteristic of permeability and influencing factors. The study also presents data on the permeability of some polymers - the most commonly used in the structure of geomembranes used in household waste facilities - as well as some of the results of ongoing research on the behaviour of high density polyethylene geomembranes in contact with the waste facilities� leachate. Diffusion was determined by measuring the weight of the vessel (water loss) daily for 30 days. The polymer influences the permeability and diffusion through the molecular and intermolecular chemical structure, the packing density, the degree of crystallinity, the crosslinking density and through the flexibility of the macromolecular chains. The results show that the permeability of polymeric geomembranes is comparable to that of a microporous material (cement stone, bentonite).

Sorption and Diffusion in Crystalline Elastomers. I. Solubility of Isomeric Hydrocarbons in Stretched Rubber

1962 ◽  
Vol 35 (1) ◽  
pp. 153-165 ◽  
Author(s):  
J. A. Barrie ◽  
B. Platt
Keyword(s):  
Natural Rubber ◽  
Marked Effect ◽  
Semicrystalline Polymers ◽  
Degree Of Crystallinity ◽  
Vapor Permeability ◽  
Stretched Polymers ◽  
Few Data ◽  
And Diffusion ◽  
The Degree Of Crystallinity ◽  
Hydrocarbon Vapor

Abstract An important property of a polymer matrix which has a marked effect on the diffusion and sorption of vapors in polymer films is the degree of crystallinity. It is well established that the presence of crystallites leads to a decrease in both vapor solubility and permeability. Even so it is only recently that attempts have been made to relate these properties quantitatively with the degree of crystallinity. Most of this work was conducted with unstrained crystalline material, and relatively few data are available for stretched polymers either crystalline or noncrystalline. It was the main object of this work to investigate in more detail interrelations of vapor solubility, vapor permeability, and degree of crystallinity or orientation. The system hydrocarbon vapor-vulcanized natural rubber has been extensively characterized with respect to vapor permeability and solubility for regions of low penetrant concentration in the temperature range 30–60° C. As such it affords a useful reference state for studying the effect on either of these properties of a given degree of crystallinity or of orientation induced by subjecting the rubber to a simple elongation. Further, compared with unstretched semicrystalline polymers, the morphology of stretched rubber is comparatively straightforward, complex spherulitic growths being absent. In Part I of this paper we present and discuss solubility data obtained for isomeric hydrocarbons in stretched vulcanized natural rubber. The corresponding diffusion data are dealt with in Part II (following article, this issue). Throughout the investigation the degree of crosslinking was maintained constant.

The Influence of e-Beam Irradiation on the Morphology and Functional Properties of UHMWPE

2013 ◽  
Vol 197 ◽  
pp. 6-12
Author(s):  
Joanna Maszybrocka ◽  
Adrian Barylski ◽  
Jerzy Cybo ◽  
Piotr Czaja
Keyword(s):  
Molecular Weight ◽  
Friction Surface ◽  
Morphological Changes ◽  
Crosslinking Density ◽  
Degree Of Crystallinity ◽  
Beam Irradiation ◽  
Sem Images ◽  
Applied Dose ◽  
Radiation Modification ◽  
The Degree Of Crystallinity

The paper presents an analysis of the effectiveness of radiation modification of GUR 1050 and GUR 1020 polymers intended for endoprosthesis bearing components. It has been demonstrated through extraction and expansion that the crosslinking density increases as the applied dose of electron irradiation and the molecular weight of polyethylene grow. The recorded changes were accompanied by an increase in the degree of crystallinity, which was more significant in the case of the more heavy GUR 1050 (compared to GUR 1020). The morphological changes are supported by the results of micromechanical, sclerometric and tribological examinations. Tribological examinations were documented with SEM images of the surface of specimens subjected to oscillatory friction (roll-block tester). Series of crosswise valleys and projections, arranged along the friction direction, were found on the friction surface. The smoothening of the surface and a lack of lamella fragments on the base specimens which were not subjected to e-beam irradiation are observed along with a reduction of wear due to the increasing dose of irradiation.

scholarly journals Estimation of the Age of Architectural Heritage Objects by Microstructural Changes of Calcite in Lime Mortars of Ancient Brickwork and Masonry

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 240
Author(s):  
Vladimir Kotlyar ◽  
Victoria Pishchulina ◽  
Alexey N. Beskopylny ◽  
Besarion Meskhi ◽  
Yury Popov ◽  
...  
Keyword(s):  
18Th Century ◽  
Degree Of Crystallinity ◽  
Architectural Heritage ◽  
Natural Conditions ◽  
Relative Age ◽  
Lime Mortars ◽  
Powder Samples ◽  
Diffraction Patterns ◽  
Cultural Monuments ◽  
The Degree Of Crystallinity

Determining the age of ancient architectural and cultural monuments is a significant scientific problem. An approach based on the transformation of portlandite into calcite and subsequent recrystallization of calcite is considered, which allows for estimating the relative age of ancient brickworks for local groups of historic buildings based on the results of diffraction studies of powder samples of carbonate mortars and measurements of samples with a known age. This article presents the results of the study of lime mortars of ancient brickwork. Under natural conditions, the process of transformation of portlandite into calcite takes from 100 to 200 years. The rate of this process is influenced by temperature, humidity, peculiarities of interaction with carbon dioxide contained in the air, etc. Examples show that portlandite is completely transformed into calcite in masonry mortars of the 18th century and that portlandite is not found in older mortars. It was determined that after the transformation of portlandite into calcite, an increase in the degree of recrystallization of calcite is observed, which manifests itself in powder diffraction patterns in the relative broadening of the diffraction peak of calcite hkl 104. In a detailed study, an estimate of the peak width at half maximum (FWHM) associated with the degree of crystallinity is effective. The actual data are given, which show that in older lime mortars the degree of recrystallization of calcite is higher than in younger ones. This fact makes it possible to indirectly determine the relative age of brickwork and masonry of various buildings of architectural heritage, which is especially relevant for the objects with the use of lime mortars of the northern provinces of the Byzantine Oecumene and other periods of various cultures.

scholarly journals Preparation and Characterization of Talc Filled Thermoplastic Polyurethane/Polypropylene Blends

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Emi Govorčin Bajsić ◽  
Vesna Rek ◽  
Ivana Ćosić
Keyword(s):  
Thermal Properties ◽  
Thermoplastic Polyurethane ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polypropylene Blends ◽  
Pp Blends ◽  
The Degree Of Crystallinity ◽  
Better Than

The effect of the addition of talc on the morphology and thermal properties of blends of thermoplastic polyurethane (TPU) and polypropylene (PP) was investigated. The blends of TPU and PP are incompatible because of large differences in polarities between the nonpolar crystalline PP and polar TPU and high interfacial tensions. The interaction between TPU and PP can be improved by using talc as reinforcing filler. The morphology was observed by means of scanning electron microscopy (SEM). The thermal properties of the neat polymers and unfilled and talc filled TPU/PP blends were studied by using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The addition of talc in TPU/PP blends improved miscibility in all investigated TPU/T/PP blends. The DSC results for talc filled TPU/PP blends show that the degree of crystallinity increased, which is due to the nucleating effect induced by talc particles. The reason for the increased storage modulus of blends with the incorporation of talc is due to the improved interface between polymers and filler. According to TGA results, the addition of talc enhanced thermal stability. The homogeneity of the talc filled TPU/PP blends is better than unfilled TPU/PP blends.

The Influence of the Degree of Crystallinity on the Glass Transition Temperature of Polymers

2013 ◽  
Vol 864-867 ◽  
pp. 751-754 ◽  
Author(s):  
Andrey Askadskii ◽  
Marina Popova ◽  
Tatyana Matseevich ◽  
Elena Kurskaya
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Degree Of Crystallinity ◽  
Low Degrees ◽  
The Degree Of Crystallinity

The influence of the degree of crystallinity of polymers on the glass transition temperature Tg of their amorphous domains is quantitatively analyzed. The analysis is made based on the Mandelkerns ideas [ concerning the restrictive effect of crystallization on the mobility of macromolecules within the amorphous domains. At low degrees of crystallinity, Tg of amorphous domains slowly increases, and then increases much faster at high degrees of crystallinity.

Study of the Activated Charcoal Structure from Water Hyacinth Based on Carbonization Temperature Variations and Activators

2021 ◽  
Vol 1028 ◽  
pp. 326-330
Author(s):  
Otong Nurhilal ◽  
Sahrul Hidayat ◽  
Dadan Sumiarsa ◽  
Maykel Manawan ◽  
Risdiana
Keyword(s):  
Carbon Material ◽  
Activated Charcoal ◽  
Water Hyacinth ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Lithium Sulfur Batteries ◽  
Amorphous Structures ◽  
Degree Of Graphitization ◽  
The Degree Of Crystallinity

The quality of the carbon material for application of electrodes in the battery is indicated by its ability to intercalate ions, atoms or molecules. Graphite is a carbon material with good intercalation capability. In this research, a carbon material in the form of activated charcoal produced from biomass of water hyacinth has been prepared, which is carbonized at various temperatures of 400, 500, and 600 °C with three different activators of ZnCl2, KOH and H3PO4. The activated charcoal will be used as a cathode composite in lithium sulfur batteries. To determine the quality of the activated charcoal, the structure properties of activated charcoal were characterized using X-ray diffraction (XRD). Several parameters that are determined from XRD data included the degree of crystallinity, and the degree of graphitization (Y). The degree of crystallinity was found in the ranges between 5.56 and 12.6%, where activated charcoal was dominated by amorphous structures. The value of the degree of graphitization was about 36%.

Study of structural and morphological changes during acсelerated oxidative degradation of mixtures of polyoxybutyrate with polycaprolactane

2021 ◽  
Vol 5 ◽  
pp. 60-69
Author(s):  
V. N. Vasilets ◽  
◽  
A. P. Pankina ◽  
E. A. Nemets ◽  
V. Yu. Belov ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Oxidative Degradation ◽  
Initial Mixture ◽  
Polymer Composite Material ◽  
Degree Of Crystallinity ◽  
Fenton Reagent ◽  
Dsc Method ◽  
The Degree Of Crystallinity ◽  
Composite Samples ◽  
Scanning Electron

Structural and morphological changes in the films of poly(oxybirutyrate-co-oxyvalerate) (P(OB-OV)) with poly-e-caprolactone (PCL) were studied by IR spectroscopy, DSC, and scanning electron microscopy during accelerated oxidative degradation under tests in Fenton reagent. It is shown by the DSC method that the phase separation of the P(OB-OV) and PCL components is observed in the initial mixture. The melting of various phases of P(OB-OV) is observed at temperatures of 147 °C and 157 °C, and PCL melts at a temperature of 61 °C. The degree of crystallinity of P(OB-OV) and PCL in the mixture is 67 % and 50 %, respectively. It was found that the degradation of poly(oxybirutyrate-co-oxyvalerate) prevails during incubation of composite samples in Fenton solution for 2 to 12 weeks. By changing the ratio of the components, it is possible to significantly change the rate of oxidative degradation, the molecular weight and the degree of crystallinity of the polymer composite material P(OB-OV):PCL.

Preparation of Chitin Whisker and Effect to Crystallization of Polylactide

2018 ◽  
Vol 773 ◽  
pp. 82-87
Author(s):  
Nichaphat Passornraprasit ◽  
Wanpen Tachaboonyakiat
Keyword(s):  
Phase Separation ◽  
Transition Temperature ◽  
Nanocomposite Films ◽  
Degree Of Crystallinity ◽  
Thermal Transition ◽  
Hydrolysis Time ◽  
Film Extrusion ◽  
Agglomeration Of Nanoparticles ◽  
Acidolysis Reaction ◽  
The Degree Of Crystallinity

The aim of this study was to investigate the effect of chitin whisker (CW) to the crystallization of polylactide (PLA) nanocomposite films. CW which obtained from acidolysis reaction was compounded with PLA pellets into nanocomposite films by cast film extrusion. The morphology and crystallinity of CW were observed by TEM and XRD, illustrated that the dimension of whisker was affected by hydrolysis time. Increasing of hydrolysis time, the length of whisker was more regular with narrower distribution. Moreover, the crystallinity of whisker was obviously increased after acid hydrolysis. The nanocomposite film showed rough surface compared to pure PLA film due to some agglomeration of nanoparticles. However, CW and PLA were well-mixed with no phase separation. The introduction of 0.1 phr of CW decrease cold-crystallization temperature (Tcc) from about 121 °C to 118 °C and also increase the degree of crystallinity around 10%. There was no difference of thermal transition temperature between pure PLA and nanocomposite films with the addition of CW more than 0.1 phr which inspected by DSC. Despite the transition temperature express insignificantly different, the degree of crystallinity of nanocomposite was increase, indicating that chitin whisker would induce the crystallinity of PLA.

scholarly journals CONTRACTING-OUT OF HOUSEHOLD WASTE COLLECTION SERVICES IN JAPAN

2017 ◽  
Vol 65 (02) ◽  
pp. 443-455
Author(s):  
NORIMICHI MATSUEDA ◽  
JUN’ICHI MIKI
Keyword(s):  
Analytical Model ◽  
Inverse Relationship ◽  
Municipal Waste ◽  
Household Waste ◽  
Private Firms ◽  
Simple Analytical Model ◽  
Waste Collection ◽  
Contracting Out ◽  
Contract Price ◽  
Set Up

We first report three empirical findings from our survey on the contracting-out of municipal waste collection services in Japan: (1) the rate of contracting-out and the contract price are inversely related, (2) this inverse relationship tapers out as the contracting rate becomes sufficiently high, and the contract price even tends to go up as the contracting rate approaches 100% and (3) there is a significant disparity in the contracting rates between the eastern and western parts of Japan. In order to account for these observations, we then set up a simple analytical model and examine its implications. Also, we discuss the issues that a potential hold-up situation could give rise to when the services are completely contracted out to private firms.

Sign in / Sign up

Export Citation Format

Share Document