The correlation between the lamellar thickness and the degree of crystallinity in semicrystalline polymers

1989 ◽  
Vol 8 (11) ◽  
pp. 1266-1268 ◽  
Author(s):  
W. F. Msuya ◽  
C. Y. Yue
Keyword(s):  
Semicrystalline Polymers ◽  
Degree Of Crystallinity ◽  
Lamellar Thickness ◽  
The Degree Of Crystallinity

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.

A direct method to determine the degree of crystallinity and lamellar thickness of polymers: application to polyethylene

Polymer ◽  
1994 ◽  
Vol 35 (21) ◽  
pp. 4537-4544 ◽  
Author(s):  
Anthony J. Ryan ◽  
Wim Bras ◽  
Geoffrey R. Mant ◽  
Gareth E. Derbyshire
Keyword(s):  
Direct Method ◽  
Degree Of Crystallinity ◽  
Lamellar Thickness ◽  
A Direct Method ◽  
The Degree Of Crystallinity

Differential scanning calorimetry/small-angle X-ray scattering analysis of ultraviolet sensible polypropylene filaments

2021 ◽  
pp. 004051752110533
Author(s):  
Martina Vikova ◽  
Shinichi Sakurai ◽  
Aravin Prince Periyasamy ◽  
Hidekazu Yasunaga ◽  
Miroslava Pechočiaková ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Pigment Concentration ◽  
Degree Of Crystallinity ◽  
Lamellar Thickness ◽  
Drawing Ratio ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
The Degree Of Crystallinity ◽  
Ray Scattering

In this work, ultraviolet (UV) sensible metallocene isotactic polypropylene (miPP) filaments were produced with different drawing ratios and various concentrations of photochromic pigment. The effects of pigment concentration and drawing ratio on the chromatic properties and the structural modification for the miPP filaments were studied extensively by differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS/WAXS) measurements. The change in melting temperature and the polymeric structures, such as lamellar thickness, long period and degree of crystallinity of miPP with the addition of a UV sensible pigment into miPP and the drawing process, were evaluated. The results show that the pigment concentration and the drawing ratio influence the inner structure of miPP filaments. Finally, our investigation shows that SAXS and also WAXS are appropriate to determine the lamellar thickness and the degree of crystallinity established by the DSC approach. This work attempts to correlate the results of lamellar thickness, the degree of crystallinity and the higher-order structure of the polymer acquired by DSC as well as X-ray diffraction (XRD) techniques in order to develop an appropriate approach to find the influence of pigment concentration and drawing ratio on miPP filaments.

Crystallinity and Unit Cell Variations in Linear High-Density Polyethylene

1994 ◽  
Vol 38 ◽  
pp. 495-502
Author(s):  
Kenneth B. Schwartz ◽  
Jinlong Cheng ◽  
Vijay N. Reddy ◽  
Matilda Fone ◽  
Howard P. Fisher
Keyword(s):  
High Density Polyethylene ◽  
Unit Cell ◽  
High Density ◽  
Degree Of Crystallinity ◽  
Lamellar Thickness ◽  
Interfacial Zone ◽  
Unit Cell Parameters ◽  
Scanning Calorimetry ◽  
Cell Parameters ◽  
The Degree Of Crystallinity

Abstract The degree of crystallinity and unit cell parameters have been determined using WAXS on a number of compression molded high-density polyethylene (HDPE) plaques processed at widely varying conditions of crystallization and annealing times and temperatures. Changes in unit cell parameters with variations in processing conditions can be explained in terms of increases in lamellar thickness of polyethylene crystals with increasing thermal treatments. Concomitant increases in the degree of crystallinity of these samples can also be explained in terms of lamellar thickening and other changes in polyethylene morphology. Crystallinity determinations using XRD data are also compared with values determined by differential scanning calorimetry (DSC) and solid-state 13C nuclear magnetic resonance (NMR). Comparisons of crystallinity values obtained by these three different techniques can reveal details of the morphology of HDPE including the presence of an interfacial zone in addition to the crystalline and amorphous components of the system.

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%.

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