Thermoanalytical Methods in Vulcanizate Analysis I. Differential Scanning Calorimetry and the Heat of Vulcanization

1975 ◽  
Vol 48 (1) ◽  
pp. 26-40 ◽  
Author(s):  
D. W. Brazier ◽  
G. H. Nickel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Natural Rubber ◽  
Magnesium Oxide ◽  
Significant Contribution ◽  
Scanning Calorimetry ◽  
Future Studies ◽  
Sulfur Vulcanization ◽  
Cure Mechanism ◽  
Soft Rubber ◽  
Made In

Abstract Our objective has been to demonstrate that DSC is a convenient and rapid technique for the study of elastomer vulcanization characteristics. Although we have been concerned only with NR and NR-BR blends, the observation of exothermicity in sulfur vulcanization is quite general. Similar observations on sulfur vulcanization of IIR, SBR, EPDM, CSM, and NBR rubbers have been made in our laboratory. In non-sulfur vulcanization systems, we have found the diurethane cure of natural rubber to be exothermic and amenable to DSC study. As reported by Bruce et al., the magnesium oxide cure of chloroprenes is exothermic, but magnesium oxide-diamine vulcanization of fluoroelastomers is characterized by very low exothermicity. Future studies of the effect of various additives on soft rubber cure could make a significant contribution to our understanding of the complex cure mechanism. Successful kinetic analysis of DSC scans is perhaps the major hurdle to be overcome before the DSC technique can be meaningfully applied to such problems.

Origin of Characteristic Properties of Natural Rubber—Synergistic Effect of Fatty Acids on Crystallization of cis-1,4-Polyisoprene: I, Saturated and Unsaturated Fatty Acids

1996 ◽  
Vol 69 (4) ◽  
pp. 600-607 ◽  
Author(s):  
Seiichi Kawahara ◽  
Naoyuki Nishiyama ◽  
Takashi Kakubo ◽  
Yasuyuki Tanaka
Keyword(s):  
Fatty Acids ◽  
Differential Scanning Calorimetry ◽  
Linoleic Acid ◽  
Methyl Linoleate ◽  
Stearic Acid ◽  
Natural Rubber ◽  
Unsaturated Fatty Acids ◽  
Crystallization Rate ◽  
Scanning Calorimetry ◽  
In Cis

Abstract The influence of stearic acid, linoleic acid and their methylesters on crystallization of synthetic cis-1,4-polyisoprene was investigated at the isothermal crystallization temperature of −25°C by means of differential scanning calorimetry and dilatometry. The overall crystallization rate of cis-1,4-polyisoprene increased in step with increasing stearic acid content, while the glass transition temperature of cis-1,4-polyisoprene did not change with the additive level. The addition of 1 wt % stearic acid or methyl stearate showed an acceleration effect on the initial crystallization of the polymer, while 1 wt % linoleic acid or methyl linoleate suppressed the initial crystallization. Coexistence of stearic acid and linoleic acid or stearic acid and methyl linoleate in cis-1,4-polyisoprene gave rise to a dramatic increase in the overall crystallization rate of the polymer. The characteristic properties of natural rubber were revealed to be related to the specific ratio of miscible fatty acids to immiscible fatty acids in natural rubber.

scholarly journals Glass Transition Temperature and Microhardness of Compatible and Incompatible Elastomer/Plastomer Blends

1970 ◽  
Vol 33 (1) ◽  
pp. 15-24 ◽  
Author(s):  
MF Mina ◽  
GH Michler ◽  
FJ Balta Calleja
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Core Shell ◽  
Scanning Calorimetry ◽  
Rubber Toughened ◽  
Shell Particles

Glass transition temperature (Tg) of core-shell particles-toughened poly(methyl- methacrylate) (CSPTPMMA) and natural rubber-toughened PMMA (NRTPMMA), which are basically the PMMA/elastomer blends with different concentrations of elastomer heterogeneously distributed in the samples, was investigated by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and microindentation technique (MT). Microhardness (H) of the samples was measured using MT. Core-shell particles (CSP) with a rubbery shell and natural rubber (NR) were used as reinforcing materials for the production of compatible and incompatible blends, respectively. Results reveal a good correlation of the glass transition temperature (Tg) obtained from DSC and DMA, and that deduced from MT.  The H-value of each sample is compared with its Tg-value. Increase of Tg with the increase of H, which is a general behavior of polymers, is not maintained in the both blends investigated. Contrary to expectation, H is shown to decrease with increasing glass transition temperature in case of CSP-toughened compatible blends while it decreases with the decrease of Tg-value only in case of NR-modified incompatible blends for lower NR concentration (<1 wt%) and does not depend on Tg for rubber content higher than 1 wt%.  Keywords: Glass transition temperature, microhardness, rubber-toughened poly(methyl -methacrylate), core-shell particle, differential scanning calorimetry DOI: 10.3329/jbas.v33i1.2946 Journal of Bangladesh Academy of Sciences, Vol. 33, No. 1, 15-24, 2009

scholarly journals The effect of different hydration media on magnesia

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Friedrich von Hoessle ◽  
Reham Farid ◽  
Mayar Mohamed ◽  
Rawia M. Hammouda ◽  
Fritz E. Kühn ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Particle Size ◽  
Magnesium Oxide ◽  
Water System ◽  
Magnesium Acetate ◽  
Distilled Water ◽  
Scanning Calorimetry ◽  
Degree Of Hydration ◽  
Acid Test

AbstractThis paper discusses the rate of hydration of magnesia (CCM1 and CCM2) during the formation of magnesium hydroxide with magnesium acetate and distilled water. The influence of magnesium acetate and the reactivity of the two types of caustic calcined magnesia were studied by thermogravimetric analysis, differential scanning calorimetry, mass spectrometry, particle size detection and pH. Also, both citric acid and acetic acid test were done to measure the reactivity of magnesium oxide powder. The results indicate that the hydration rate of both oxides in magnesium acetate system are vigorously exothermic compared to the water system. The study shows mechanistically that magnesium acetate enhanced the degree of hydration of magnesium oxide due to the presence of acetate ions and Mg2+ ions when it compared to water. Mathematical models confirm the findings.

Quantification of the distribution of carbon black in natural rubber/polybutadiene blends by differential scanning calorimetry

2009 ◽  
Vol 49 (8) ◽  
pp. 1544-1552 ◽  
Author(s):  
Julien Portal ◽  
Christian Carrot ◽  
Jean-Charles Majeste ◽  
Stéphane Cocard ◽  
Vincent Pelissier ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Carbon Black ◽  
Natural Rubber ◽  
Scanning Calorimetry
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