The influence of crystalline texture on the tensile properties of natural rubber. I

1974 ◽  
Vol 338 (1615) ◽  
pp. 459-478 ◽  
Keyword(s):  
Glass Transition ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Amorphous Phase ◽  
Crystalline Phase ◽  
Full Range ◽  
Glassy Matrix ◽  
Tensile Behaviour ◽  
Crystalline Morphology ◽  
Temperature Range

The crystalline morphologies that are attainable in samples of natural rubber (n. r.), by extending the samples prior to crystallization, are reviewed. Specimens covering the full range of crystalline morphologies possible have been prepared and tensile tested between – 120 and – 26 °C. The tensile behaviour of crystalline samples is compared and contrasted with that of oriented, but non-crystalline, identical natural rubber in the same temperature range. It is found that the tensile behaviour of semi-crystalline n. r. is dominated by the amorphous phase throughout the temperature range – 120 to – 26 °C. At temperatures above the glass transition temperature ( T g ) of the amorphous phase, the crystalline phase acts mainly as a diluent of the amorphous phase. At temperatures below T g , where the crystalline phase is set in a glassy matrix, it is found that the crystalline morphology does significantly affect the tensile behaviour. Attempts are made to differentiate the effects of crystallinity, crystalline morphology and orientation of the amorphous phase on the tensile properties of natural rubber.

Thermopolarization Phenomena in the Temperature Range of Glass Transition of Amorphous Polydiethylsiloxane

2018 ◽  
Vol 773 ◽  
pp. 15-19
Author(s):  
I.V. Popov
Keyword(s):  
Glass Transition ◽  
Amorphous Phase ◽  
Elastic State ◽  
Structural Units ◽  
Flexible Chain ◽  
Experimental Conditions ◽  
Temperature Range ◽  
Maximum Value ◽  
Temperature Dependences ◽  
Amorphous Phase Formation

The transition from the glass to the highly elastic state in polydiethylsiloxane (PDES) is not reflected on the temperature dependences of the relative permittivity, the dielectric loss tangent, and the specific volumetric electrical conductivity. But, the peak of the current of thermostimulated depolarization (TSD) is fixed in the temperature range of the transition to the highly elastic state. The peak of the TSD current at T ~ 130K indicates a continuous amorphous phase formation in the experimental conditions. The maximum value of the TSD current directly depends on the content of the amorphous phase in the polymer. The cooling of the polymer in an electric field reduces the magnitude of the peak. Exposure in the mesophase leads to an almost complete absence of thermopolarization effects near the glass transition temperature. This peak of the TSD current in the absence of preliminary polarization is characteristic, presumably, only for flexible-chain polymers where structural units have pyroelectric properties. Under certain conditions, PDES demonstrates itself as an active dielectric in the temperature range of 90 - 180K.

The Crystallization of Weakly Vulcanized Rubber by Pressure

1940 ◽  
Vol 13 (1) ◽  
pp. 48-48 ◽  
Author(s):  
P. A. Thiessen ◽  
W. Kirch
Keyword(s):  
Melting Point ◽  
Natural Rubber ◽  
Crystalline Phase ◽  
Normal Pressure ◽  
Latex Film ◽  
X Rays ◽  
Amorphous Substance ◽  
Temperature Range ◽  
Vulcanized Rubber

Abstract Crystallization can be brought about in weakly vulcanized rubber by the method described by Thiessen and Kirsch for natural rubber. When samples of this type of vulcanized rubber were exposed to x-rays below + 6° C, but not under pressure, then Debye-Scherrer diagrams corresponding to those of a crystallized latex film were obtained. To determine the influence of pressure on these vulcanizates, samples were subjected to pressure on all sides in the chambers of the pressure apparatus described in the earlier work. After having been exposed for 100 days the sample which had been kept at + 6° C under 30 atmospheres' pressure showed a very marked Debye-Scherrer diagram, whereas samples kept at the same temperature but at normal pressure showed only the halo of an amorphous substance. Consequently pressure has an influence on the crystallization of vulcanized rubber as well as of raw rubber. The melting point of the crystalline phase lies between + 11° C. and +13° C. Obviously then an increase in pressure raises the temperature range of supercooling.

Thermodynamic Properties of Natural Rubber and Isoprene

1966 ◽  
Vol 39 (1) ◽  
pp. 143-148 ◽  
Author(s):  
R. W. Warfield ◽  
M. C. Petree
Keyword(s):  
Free Energy ◽  
Glass Transition ◽  
Thermodynamic Properties ◽  
Natural Rubber ◽  
Specific Heat ◽  
Gibbs Free Energy ◽  
Kcal Mole ◽  
Specific Heat Data ◽  
Temperature Range ◽  
Heat Data

Abstract Using published specific heat data, the entropy, enthalpy, and Gibbs free energy of natural rubber (NR) have been calculated over the temperature range 0 to 320° K. The thermodynamic function Cp/T as a function of T calculated for NR exhibits a maximum at 50° K and another maximum at 210° K, which is associated with the glass transition. The number of classically vibrating units per repeating unit of NR is 6.61 at 300° K. These functions have also been calculated for isoprene over the temperature range 0 to 300° K. At 298.16° K the entropy of polymerization was found to be 24.00 cal mole−1deg−1 and the free energy of polymerization − 10.7 kcal/mole.

KANTHAL 135 R05

Alloy Digest ◽  
2010 ◽  
Vol 59 (8) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Temperature Range

Abstract Kanthal 135 R05 is a thermostatic bimetal and is recommended for use in the temperature range -20 to 250 deg C (-4 to 482 deg F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming. Filing Code: FE-152. Producer or source: Kanthal AB.

INDALLOY 160-190

Alloy Digest ◽  
1984 ◽  
Vol 33 (1) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Precision Measurement ◽  
Heat Treating ◽  
Spray Forming ◽  
Growth Behavior ◽  
Temperature Range

Abstract INDALLOY 160-190 is a bismth-base low-melting alloy that melts through th temperature range 160-190 F. It shrinks immediately upon solidification, grows back to zero in about one hour and then shows additional growth. This shrinkage-growth behavior makes it an ideal alloy for proof casting and precision measurement of internal dimensions. This alloy originally was developed for use by children for casting soldiers and other small objects. It performs best among the low-melting alloys for spraying in the spray forming of masks and molds and in metallizing. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on casting, heat treating, machining, and joining. Filing Code: Bi-34. Producer or source: Indium Corporation of America.

KANTHAL 200/72

Alloy Digest ◽  
2008 ◽  
Vol 57 (2) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Temperature Range

Abstract Kanthal 200/72, a thermostatic bimetal, is recommended for use in the temperature range −20 to 250 deg C (−4 to 480 deg F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. Filing Code: MN-3. Producer or source: Kanthal AB.

NICKELVAC L-605

Alloy Digest ◽  
1967 ◽  
Vol 16 (10) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Base Alloy ◽  
Heat Treating ◽  
Temperature Range ◽  
Temperature Performance ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract NICKELVAC L-605 is a double vacuum melted, cobalt-base alloy for high temperature applications. It is recommended for highly stressed parts operating in the temperature range of 1700 to 2000 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Co-53. Producer or source: Allvac Metals Company, A Teledyne Company.

scholarly journals Rheometer Evidences for the Co-Curing Effect of a Bismaleimide in Conjunction with the Accelerated Sulfur on Natural Rubber/Chloroprene Rubber Blends

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1510
Author(s):  
Marek Pöschl ◽  
Shibulal Gopi Sathi ◽  
Radek Stoček ◽  
Ondřej Kratina
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Crosslinking Agent ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ene Reactions ◽  
Rubber Blends ◽  
Diels Alder Reaction ◽  
Chloroprene Rubber

The rheometer curing curves of neat natural rubber (NR) and neat chloroprene rubber (CR) with maleide F (MF) exhibit considerable crosslinking torque at 180 °C. This indicates that MF can crosslink both these rubbers via Alder-ene reactions. Based on this knowledge, MF has been introduced as a co-crosslinking agent for a 50/50 blend of NR and CR in conjunction with accelerated sulfur. The delta (Δ) torque obtained from the curing curves of a blend with the addition of 1 phr MF was around 62% higher than those without MF. As the content of MF increased to 3 phr, the Δ torque was further raised to 236%. Moreover, the mechanical properties, particularly the tensile strength of the blend with the addition of 1 phr MF in conjunction with the accelerated sulfur, was around 201% higher than the blend without MF. The overall tensile properties of the blends cured with MF were almost retained even after ageing the samples at 70 °C for 72 h. This significant improvement in the curing torque and the tensile properties of the blends indicates that MF can co-crosslink between NR and CR via the Diels–Alder reaction.

Design of Compact Full-range Laser Methane Sensor with Wide Temperature Range

2020 ◽  
Vol 49 (10) ◽  
pp. 1012002-1012002
Author(s):  
庞涛 Tao PANG ◽  
孙鹏帅 Peng-shuai SUN ◽  
张志荣 Zhi-rong ZHANG ◽  
吴边 Bian WU ◽  
夏滑 Hua XIA ◽  
...  
Keyword(s):  
Wide Temperature Range ◽  
Full Range ◽  
Methane Sensor ◽  
Temperature Range

scholarly journals The effects of alkanolamide addition on cure characteristics, swelling behaviour and tensile properties of silica-filled natural rubber (NR) / chloroprene rubber (CR) blends

2018 ◽  
Vol 34 ◽  
pp. 01030 ◽  
Author(s):  
Indra Surya ◽  
Syahrul Fauzi Siregar ◽  
Hanafi Ismail
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Crosslink Density ◽  
Tensile Modulus ◽  
Palm Stearin ◽  
Swelling Behaviour ◽  
Elongation At Break ◽  
Cure Characteristics ◽  
Chloroprene Rubber

Effects of alkanolamide (ALK) addition on cure characteristics, swelling behaviour and tensile properties of silica-filled natural rubber (NR)/chloroprene rubber (CR) blends were investigated. The ALK was synthesized from Refined Bleached Deodorized Palm Stearin (RBDPS) and diethanolamine, and incorporated into the silica-filled NR/CR blends as a non-toxic rubber additive. The ALK loadings were 0.0, 1.0, 3.0, 5.0 and 7.0 phr. It was found that the ALK exhibited shorter scorch and cure times and higher elongation at break of the silica-filled NR/CR blends. The ALK also exhibited higher torque differences, tensile modulus and tensile strength at a 1.0 phr of ALK loading and then decreased with further increases in the ALK loading. The swelling measurement proved that the 1.0 phr loading of ALK caused the highest degree in crosslink density of the silica-filled NR/CR blends.

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