Crystallization of Cis-Polyisoprenes in a Capillary Rheometer. I

1971 ◽  
Vol 44 (1) ◽  
pp. 1-11 ◽  
Author(s):  
V. L. Folt ◽  
R. W. Smith ◽  
C. E. Wilkes
Keyword(s):  
Natural Rubber ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Fibrillar Structure ◽  
Capillary Rheometer ◽  
X Ray ◽  
Complex Morphology ◽  
Structure Changes ◽  
Degree Of Orientation ◽  
Commercial Processing

Abstract Natural rubber is readily crystallized under the pressure and orientation forces existing in a capillary rheometer. The crystallization of natural rubber is readily effected over the temperature range covering commercial processing and fabricating temperatures. The crystalline rubber is stable at atmospheric pressure and room temperature. The observed crystalline melting point increases with increasing crystallization temperatures. Wide angle x-ray pictures show the crystals to be highly oriented in the direction of flow. Electron micrographs of fracture surfaces of the crystalline rubber show the existence of a very complex morphology. Where the degree of orientation is highest, a fibrillar structure is observed parallel to the direction of flow. The fibrillar structure changes to a shish-kebab structure about midway down the capillary. Apparently, a regrouping occurs with chain folded lamellae forming at right angles to the oriented fibrillar type crystals. A rotation of the chain-folded lamellae may occur as the exit end of the capillary is approached.

Synthesis of Graphene Oxide Grafted with Epoxidized Natural Rubber via Aminosilane Linkage

2018 ◽  
Vol 940 ◽  
pp. 28-34
Author(s):  
Pollawat Charoeythornkhajhornchai ◽  
Anongnat Somwangthanaroj
Keyword(s):  
Graphene Oxide ◽  
Natural Rubber ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Interfacial Interaction ◽  
Epoxidized Natural Rubber ◽  
Rubber Matrix ◽  
Mixing Process ◽  
X Ray ◽  
Transmission Electron

Graphene oxide was synthesized from graphite by Hummer method and connected with (3-aminopropyl) triethoxysilane to form graphene oxide-aminosilane (GO-Si) linkage. The solution was centrifuged and washed with acetone to remove unreacted aminosilane before grafting with epoxidized natural rubber (ENR). ENR dissolved in toluene solution was mixed with GO-Si particle and dried at room temperature. Then, it was grafted to form graphene oxide grated with ENR via aminosilane linkage (GO-Si-ENR) by heat treatment. GO-Si-ENR was washed in toluene to remove unconnected ENR molecule. The synthesized GO particle in each step was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The possible reaction mechanism was proposed in this research. The aim of this synthesis is to improve natural rubber - graphene interfacial interaction thus the dispersion of GO and GO-Si-ENR particle in natural rubber matrix by solvent mixing process was observed by transmission electron microscopy (TEM).

Thermal expansion of nepheline-kalsilite crystalline solutions

2003 ◽  
Vol 67 (3) ◽  
pp. 535-546 ◽  
Author(s):  
G. L. Hovis ◽  
J. Crelling ◽  
D. Wattles ◽  
B. Dreibelbis ◽  
A. Dennison ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Significant Degree ◽  
Tetrahedral Framework ◽  
X Ray ◽  
Structure Changes ◽  
Increasing Temperature ◽  
Expansion Behaviour

AbstractEleven nepheline-kalsilite crystalline solutions with various proportions of K:Na have been studied from room temperature to 1050/11500C by X-ray powder diffraction. Nepheline expansion is relatively high and little affected by composition, whereas kalsilite expansion is lower but affected to a significant degree by K:Na ratio. The generally higher rate of expansion in nepheline is apparently related to the collapse of the tetrahedral framework around the smaller of its two alkali sites. Occupancy of these sites by the relatively small Na ion fürther extends the potential for thermal vibration before the structure is stretched to the critical degree required for phase transformation. Once the structure changes to that of kalsilite, with its single alkali site, an increase in content of the larger K ion limits the degree to which kalsilite can expand. Crucial to the overall expansion behaviour of these minerals are the specific tetrahedral configurations of nepheline vs. kalsilite, the number and geometry of their alkali sites, the occupancies of those sites, and the flexibility inherent in each structure that allows for adjustment with increasing temperature.

scholarly journals The Thermal Behavior of γ-PA1010: Evolution of Structure and Morphology in the Simultaneous Thermal Stretched Films

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1722 ◽  
Author(s):  
Zhenya Zhang ◽  
Wentao Liu ◽  
Hao Liu ◽  
Aihua Sun ◽  
Yeonwoo Yoo ◽  
...  
Keyword(s):  
Draw Ratio ◽  
Room Temperature ◽  
Tensile Force ◽  
X Ray ◽  
Maximum Value ◽  
Degree Of Orientation ◽  
Higher Temperature ◽  
Evolution Of Structure ◽  
The Difference ◽  
Polyamide 1010

In this work, polyamide 1010 (PA1010) films were prepared by melt-quenching. A wide-angle X-ray diffractometer (WAXD) with a thermal stretching stage was used to investigate the structure transformation, crystallinity and degree of orientation in the course of simultaneous thermally stretched PA1010. The crystallinity increased along with the increase of draw ratio and then decreased as the draw ratio was over 2.00 times—which the maximum value reached when the draw ratio was about 2.00 times. The degree of orientation of γ-PA1010 was much greater at higher temperature than room temperature (RT); the difference gradually became weaker with the increase of draw ratio. There was a linear relationship between the draw ratios and tensile force at higher temperatures, and the tensile force increased with the increase of draw ratios. The tensile force may induce crystallization and promote orientation in the course of simultaneous thermally stretched PA1010. These phenomena are beneficial to understand the structure-processing-performance relationship and provide some theoretical basis for the processing and production.

X-Ray Diffraction Studies of Crystallization in Elastomers

1956 ◽  
Vol 29 (2) ◽  
pp. 438-450 ◽  
Author(s):  
Leroy E. Alexander ◽  
Stanley Ohlberg ◽  
G. Russell Taylor
Keyword(s):  
Natural Rubber ◽  
Molecular Orientation ◽  
Room Temperature ◽  
Geiger Counter ◽  
Preferred Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Integrated Intensity ◽  
Beam Monitor

Abstract In general, extension of an elastomer results in a degree of preferred orientation of the molecular chains composing the amorphous phase. Therefore the amorphous fraction of a partially crystalline elastomer must be related to the integrated intensity of the amorphous diffraction halo rather than to the intensity at any one azimuth. A noteworthy exception is natural rubber, for which simple meridional measurements suffice. A Geiger-counter apparatus, with beam monitor and temperature-controlling accessories, is described for making accurate measurements of the x-ray intensities scattered at any azimuth and at small or moderate Bragg angles. Measurements of crystallinity in natural rubber are in essential agreement with the findings of previous workers. When polybutadiene is extended at room temperature, molecular orientation occurs, but little if any crystallization. Measurements at lowered temperatures show that the crystalline fraction becomes appreciable at about 0° C and that it increases with further reduction of temperature and with increasing extension ratio. Preferred orientation of the crystalline regions in extended polybutadiene has been measured quantitatively with the object of providing jointly with birefringence measurements a value of the birefringence of a single crystal of polybutadiene.

scholarly journals Morphological Study on Room-Temperature-Cured PMMA-Grafted Natural Rubber-Toughened Epoxy/Layered Silicate Nanocomposite

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
N. Y. Yuhana ◽  
S. Ahmad ◽  
M. R. Kamal ◽  
S. C. Jana ◽  
A. R. Shamsul Bahri
Keyword(s):  
Electron Microscopy ◽  
Natural Rubber ◽  
Morphological Study ◽  
Room Temperature ◽  
Layered Silicate ◽  
Tem Analysis ◽  
X Ray ◽  
Toughened Epoxy ◽  
Cloisite 30B ◽  
Unmodified Epoxy

A morphological study was conducted on ternary systems containing epoxy, PMMA-grafted natural rubber, and organic chemically modified montmorillonite (Cloisite 30B). Optical microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and wide-angle X-ray diffraction (WAXD) analysis were used. The following four materials were prepared at room temperature: cured unmodified epoxy, cured toughened epoxy, cured unmodified epoxy/Cloisite 30B nanocomposites, and cured toughened epoxy/Cloisite 30B nanocomposites. Mixing process was performed by mechanical stirring. Poly(etheramine) was used as the curing agent. The detailed TEM images revealed co-continuous and dispersed spherical rubber in the epoxy-rubber blend, suggesting a new proposed mechanism of phase separation. High-magnification TEM analysis showed good interactions between rubber and Cloisite 30B in the ternary system. Also, it was found that rubber particles could enhance the separation of silicates layers. Both XRD and TEM analyses confirmed that the intercalation of Cloisite 30B was achieved. No distinct exfoliated silicates were observed by TEM. Aggregates of layered silicates (tactoids) were observed by SEM and EDX, in addition to TEM at low magnification. EDX analysis confirmed the presence of organic and inorganic elements in the binary and ternary epoxy systems containing Cloisite 30B.

scholarly journals Investigation of the possibility of the reutilization of some industrial wastes

2005 ◽  
Vol 70 (6) ◽  
pp. 843-851 ◽  
Author(s):  
A. Kostic-Pulek ◽  
S. Marinkovic ◽  
S. Popov ◽  
J. Djinovic
Keyword(s):  
Atmospheric Pressure ◽  
Room Temperature ◽  
Bottom Ash ◽  
Calcium Sulphate ◽  
Industrial Wastes ◽  
Mass Ratio ◽  
Solid Mass ◽  
X Ray ◽  
Mass Ratios ◽  
Ir Analysis

The utilization of nitrogypsum and bottom ash, wastes from the factory "Milan Blagojevic" (Lucani?Serbia), was investigated. For this purpose, mixtures composed of calcined nitrogypsum (CaSO4. 0,5H2O), ash (mass ratio 1:1) and water (water/solid mass ratio 0.5), as well as similar mixtures consisting of 1.0 mass%5.0 mass%10.0mass%of lime (CaO) with the same gypsum/ash and water/solid mass ratios, were prepared. These mixtures gave solidified products at room temperature and atmospheric pressure, which after 28 days had satisfactory compressive strengths for application in the civil industry. The product with 5.0mass%of added lime has the best mechanical characeristics. X-ray and qualitative IR analysis showed that this product mainly consisted of calcium sulphate dihydrate (CaSO4.2H2O) and carbonates, as well as a small quantity of ettringite (3CaO.Al2O3.3CaSO4.32H2O).

scholarly journals Time-resolved laboratory micro-X-ray fluorescence reveals silicon distribution in relation to manganese toxicity in soybean and sunflower

2020 ◽  
Vol 126 (2) ◽  
pp. 331-341
Author(s):  
Antony van der Ent ◽  
Lachlan W Casey ◽  
F Pax C Blamey ◽  
Peter M Kopittke
Keyword(s):  
Glycine Max ◽  
Atmospheric Pressure ◽  
Plant Material ◽  
Room Temperature ◽  
Light Elements ◽  
Time Resolved ◽  
X Ray ◽  
Highly Sensitive ◽  
Distribution Of Elements ◽  
Highly Sensitive Detection

Abstract Background and Aims Synchrotron- and laboratory-based micro-X-ray fluorescence (µ-XRF) is a powerful technique to quantify the distribution of elements in physically large intact samples, including live plants, at room temperature and atmospheric pressure. However, analysis of light elements with atomic number (Z) less than that of phosphorus is challenging due to the need for a vacuum, which of course is not compatible with live plant material, or the availability of a helium environment. Method A new laboratory µ-XRF instrument was used to examine the effects of silicon (Si) on the manganese (Mn) status of soybean (Glycine max) and sunflower (Helianthus annuus) grown at elevated Mn in solution. The use of a helium environment allowed for highly sensitive detection of both Si and Mn to determine their distribution. Key Results The µ-XRF analysis revealed that when Si was added to the nutrient solution, the Si also accumulated in the base of the trichomes, being co-located with the Mn and reducing the darkening of the trichomes. The addition of Si did not reduce the concentrations of Mn in accumulations despite seeming to reduce its adverse effects. Conclusions The ability to gain information on the dynamics of the metallome or ionome within living plants or excised hydrated tissues can offer valuable insights into their ecophysiology, and laboratory µ-XRF is likely to become available to more plant scientists for use in their research.

Crystallization of Cis-Polyisoprenes in a Capillary Rheometer. III. The Effects of Certain Additives

1971 ◽  
Vol 44 (1) ◽  
pp. 29-39 ◽  
Author(s):  
V. L. Folt
Keyword(s):  
Natural Rubber ◽  
Room Temperature ◽  
Crystallization Process ◽  
Solidification Process ◽  
Polymer Chains ◽  
Capillary Rheometer ◽  
Subsequent Aging ◽  
Oil Blends ◽  
Flow Units ◽  
Static Conditions

Abstract Cis-polyisoprenes are readily crystallized under the pressure and orientation forces existing in a capillary rheometer. Oil-extension retards the rheometer crystallization process. However, natural rubber/oil blends containing up to 50 phr of oil are readily crystallized above room temperature. The retardation effect of oil-extension is not nearly as drastic as that produced by slight alterations in the stereoregularity of the polymer chains. ISAF carbon black significantly enhances the ease at which solidification of the melt can be effected in the capillary. Aging the black/rubber mix at room temperature enhances the ease of solidification. Shearing the aged black/rubber mix results in a retardation of the solidification process but subsequent aging of the sheared mix again enhances the ease of solidification in the capillary. Acetone extracted natural rubber crystallizes more easily in the capillary rheometer than the non-extracted material; a behavior in marked contrast to that observed under static conditions at −20° C where removal of the acetone solubles from natural rubber retards the crystallization process. A brief discussion of the crystallization mechanism in terms of supermolecular flow units is presented.

Electrochemical Synthesis of Methoxy-Dimethylbenzene and its Application in Gasoline

2012 ◽  
Vol 441 ◽  
pp. 403-407
Author(s):  
Feng Tao Chen ◽  
San Chuan Yu ◽  
Shi Shen Zhang
Keyword(s):  
Fourier Transform ◽  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Main Product ◽  
Metal Salt ◽  
Chemical Conversion ◽  
X Ray ◽  
Porous Graphite ◽  
Good Catalytic Activity

P, Mo metal-salt catalysts (MxOy-MoO3-P2O5,M = Cu, V, Ni, Cr) were prepared and investigated by means of Fourier transform infrared and X-ray photoelectron spectroscopy. All catalysts exhibited good catalytic activity for the electrochemical catalytic oxidation ofp-xylene in methanol solvent assisted with a pair of porous graphite plane electrodes at room temperature and atmospheric pressure. Higher than 88% chemical conversion of the main product (methoxy-dimethylbenzene) was observed, and the products used as booster to improve fuel combustion were also studied.

Reduction of Radiation Damage in Organics by Cooling to 4K and Embedding

1981 ◽  
Vol 39 ◽  
pp. 22-23
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Radiation Damage ◽  
Room Temperature ◽  
Additional Data ◽  
Good Tool ◽  
X Ray ◽  
Structure Changes ◽  
Diffraction Patterns ◽  
Small Periodic ◽  
Ray Methods

Structure determination of organic, in particular biological, material is performed with x-ray methods, if sufficiently large crystals are available. In the case of small periodic regions a good tool is electron diffraction. However, the information gained with this method will in general hardly do. The necessary additional data can be obtained e.g. by direct imaging with the electron microscope. Unfortunately structure changes due to the electron impact make imaging very difficult with a resolution below 20 Å. Recently it has been established that radiation damage can be drastically reduced by cooling the specimen to 4 K1 or by embedding it in an amorphous matrix. In the following the radiation protection achieved by combining both methods is shown on the example of the organic complex Cu-bis-salicyloylhydracin (Cu-BSH) which is interesting for cable technology.The specimens are prepared by solving BSH in NH3 and subsequently adding copper tretamin solution. The needle-shaped crystals which precipitate are spread on holey carbon foil (Fig. 1). Diffraction patterns were taken at room temperature and at 4 K.

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