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.

scholarly journals Impact of environmental agents on non-woven polylactide/natural rubber agrofiber

2021 ◽  
Vol 285 ◽  
pp. 07034
Author(s):  
Yulia Tertyshnaya ◽  
Maksim Zakharov ◽  
Alina Ivanitskikh ◽  
Anatoliy Popov
Keyword(s):  
Natural Rubber ◽  
Uv Irradiation ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
Distilled Water ◽  
Fibrous Materials ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Environmental Agents ◽  
The Degree Of Crystallinity

In the work an eco-friendly non-woven fiber made of polylactide and natural rubber with a rubber content from 0 to 15 wt.% was obtained by electrospinning. The influence of distilled water and UV irradiation on the agrofibers has been investigated. The water sorption test showed that the addition of natural rubber into the polylactide matrix does not significantly affect the degree of water absorption of the fibrous materials, which is in the range of 49-50.6%. Thermal characteristics after 180 days of degradation in distilled water at 22±2 oC and UV irradiation at a wavelength of 365 nm during 100 hours were determined using the differential scanning calorimetry. Changes in the values for glass transition and melting temperatures, and the degree of crystallinity were determined.

scholarly journals Selectively Etched Halloysite Nanotubes as Performance Booster of Epoxidized Natural Rubber Composites

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3536
Author(s):  
Indra Surya ◽  
Kamaruddin Waesateh ◽  
Abdulhakim Masa ◽  
Nabil Hayeemasae
Keyword(s):  
Natural Rubber ◽  
Treatment Time ◽  
Halloysite Nanotubes ◽  
Epoxidized Natural Rubber ◽  
Degree Of Crystallinity ◽  
X Ray Scattering ◽  
Natural Rubber Composites ◽  
Matrix Interactions ◽  
Strain Induced Crystallization ◽  
The Degree Of Crystallinity

Halloysite Nanotubes (HNT) are chemically similar to clay, which makes them incompatible with non-polar rubbers such as natural rubber (NR). Modification of NR into a polar rubber is of interest. In this work, Epoxidized Natural Rubber (ENR) was prepared in order to obtain a composite that could assure filler–matrix compatibility. However, the performance of this composite was still not satisfactory, so an alternative to the basic HNT filler was pursued. The surface area of HNT was further increased by etching with acid; the specific surface increased with treatment time. The FTIR spectra confirmed selective etching on the Al–OH surface of HNT with reduction in peak intensity in the regions 3750–3600 cm−1 and 825–725 cm−1, indicating decrease in Al–OH structures. The use of acid-treated HNT improved modulus, tensile strength, and tear strength of the filled composites. This was attributed to the filler–matrix interactions of acid-treated HNT with ENR. Further evidence was found from the Payne effect being reduced to 44.2% through acid treatment of the filler. As for the strain-induced crystallization (SIC) in the composites, the stress–strain curves correlated well with the degree of crystallinity observed from synchrotron wide-angle X-ray scattering.

The Degree of Crystallinity in Natural Rubber. IV. The Degree of Crystallization in Frozen Raw Rubber and Stretched Vulcanized Rubber

1950 ◽  
Vol 23 (2) ◽  
pp. 310-319 ◽  
Author(s):  
J. M. Goppel ◽  
J. J. Arlman
Keyword(s):  
Natural Rubber ◽  
Experimental Evidence ◽  
Theoretical Investigation ◽  
Degree Of Crystallinity ◽  
X Ray ◽  
Crystallization Point ◽  
Vulcanized Rubber ◽  
Degree Of Crystallization ◽  
The Degree Of Crystallinity

Abstract An improved x-ray technique has been worked out to determine the degree of crystallinity in natural rubber. Inaccuracies which sometimes occur in quantitative x-ray measurements were eliminated, and it has been shown that the amount of crystalline rubber, both in frozen samples of raw rubber and in stretched vulcanized rubber, could be determined fairly accurately. More experiments were carried out and the results are described. These results, which confirm the current views on the problem of crystallization, point to relatively low degress of crystallization, even in highly stretched rubber, and they agree with some other experimental evidence and with a recent theoretical investigation.

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).

The Degree of Crystallinity in Natural Rubber. III. Correlation between X-Ray and Density Measurements

1950 ◽  
Vol 23 (2) ◽  
pp. 306-310 ◽  
Author(s):  
J. J. Arlman
Keyword(s):  
Natural Rubber ◽  
Unit Cell ◽  
Degree Of Crystallinity ◽  
X Rays ◽  
Density Measurements ◽  
X Ray ◽  
Degree Of Crystallization ◽  
The Degree Of Crystallinity

Abstract In 1925 Katz discovered the crystallization of stretched rubber. In the following years several investigators tried to determine the structure of rubber crystallites. The densities of the rubber crystallites calculated from the results of these investigations varied strongly. The results of x-ray and density measurements on crude rubber carried out by the author can be made to correspond only when the latter are based on the unit cell of Bunn. It is shown by experiment that, to measure the correct degree of crystallization, it is necessary to use monochromatic x-rays.

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