Stability of Synthetic Rubber Dispersions. I. Low-temperature Thickening of Neoprene Latex.

1947 ◽  
Vol 51 (2) ◽  
pp. 443-450
Author(s):  
H. K. Livingston
Keyword(s):  
Low Temperature ◽  
Synthetic Rubber

Effect of Storage and Temperature on Flexibility of Natural and Synthetic Rubbers

1948 ◽  
Vol 21 (4) ◽  
pp. 864-876
Author(s):  
John B. Gregory ◽  
Irving Pockel ◽  
John F. Stiff
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Strain Curve ◽  
Polymer Chains ◽  
Stress Strain Curve ◽  
Low Temperature Storage ◽  
Synthetic Rubber ◽  
Loading And Unloading ◽  
Temperature Storage ◽  
Natural And Synthetic

Abstract A new method for measuring the flexibility of rubber has been described. The method consists essentially in determining the stress-strain curve obtained by loading and unloading a loop formed from a one-inch by six-inch strip cut from a test slab. A coefficient of flexibility independent of the thickness of the sample and, in addition, information on per cent resilience were obtained. By the use of the method described, the behavior of various natural and synthetic rubber gas mask facepiece compounds was studied during one month to three months' exposure at various temperatures down to −20° F. Progressive stiffening probably due to crystallization was found for natural rubber, GR-I, and GR-M compounds at low temperatures. No tendency to crystallize was noted for the GR-S compound. Of the crystallizable polymers GR-I was the most resistant, and GR-M the least resistant to stiffening during low temperature storage. It is of course evident that different polymers have inherently different degrees of resistance to low temperatures. Disregarding these inherent differences the work reported indicates that the resistance of elastomer compounds to stiffening during prolonged low temperature storage is favored by the following: 1. Use of interpolymers made from monomer mixtures having a relatively large proportion of each component, thus obtaining mutual intereference with crystallization. 2. Use of a “tight” cure which probably so impedes the movement of the polymer chains as to make crystallization difficult.

Crystallizable Trans-Butadiene-Piperylene Elastomers

1978 ◽  
Vol 51 (5) ◽  
pp. 907-924 ◽  
Author(s):  
M. Bruzzone ◽  
A. Carbonaro ◽  
L. Gargani
Keyword(s):  
Glass Transition ◽  
Melting Point ◽  
Low Temperature ◽  
Temperature Sensitivity ◽  
General Purpose ◽  
Strain Sensitivity ◽  
Rational Utilization ◽  
Green Strength ◽  
Synthetic Rubber ◽  
Vanadium Based Catalysts

Abstract The synthesis of a crystallizable synthetic rubber based on butadiene and piperylene in the presence of active vanadium-based catalysts is described. This outlet for piperylene (a cocomponent with isoprene of the C5 cut of naphtha crackers) would allow a rational utilization of both monomers present in the same cut and draw the best advantage from the complementary properties of the copolymer described in this work and cis-1,4-polyisoprene. The butadiene units in the copolymer are in the trans-1,4-configuration. The piperylene content giving a good compromise between crystallization at low temperature (temperature sensitivity) and crystallization upon stretching (strain sensitivity) is 30 ± 5 mol%. The copolymer shows outstanding green strength and tack, and it is less prone than high-cis-polybutadiene and trans-polypentenamer to crystallization at low temperature, because of a particular combination of thermodynamic parameters. Among these, melting point and glass transition are somewhat adjustable by controlling the piperylene content in the range specified. The properties of this crystallizable rubber suggest its use as a general-purpose rubber, possibly in combination with other conventional elastomers.

Elastomer-Resin Blends. Acrylonitrile Type Synthetic Rubber and Polyvinyl Chloride Resins

1949 ◽  
Vol 22 (3) ◽  
pp. 735-755
Author(s):  
D. W. Young ◽  
D. J. Buckley ◽  
R. G. Newberg ◽  
L. B. Turner
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Polyvinyl Chloride ◽  
Sodium Acetate ◽  
Blocking Temperature ◽  
Acrylonitrile Copolymer ◽  
Rubber Blends ◽  
Synthetic Rubber ◽  
Cure Time ◽  
Acrylonitrile Copolymers

Abstract 1. 1,3-Butadiene-acrylonitrile copolymers were mill-mixed with benzothiazoyl disulfide, sulfur, litharge, and vinyl resins, such as Vinylite (VYNW), and Saran and cured to compounds with good tensile strength, modulus, hardness, solvent resistance, and blocking temperature. 2. Results show that higher acrylonitrile type of copolymers give cured Vinylite-rubber blends with higher tensile strength, higher 100 per cent modulus, and greater ultimate elongation to break than low acrylonitrile copolymers. 3. The low temperature properties of the cured blends improve as the acrylonitrile content of the synthetic rubber is reduced. 4. An effective cure at 287° F is obtained in 15 to 30 minutes by using 2 parts of accelerator and 2 parts of sulfur per hundred parts of 1,3-butadieneacrylonitrile type copolymer-Vinylite blends. Added amounts of sulfur, and accelerator did not improve the properties or decrease the cure time at 287° F. 5. Some of the cured blends studied are free of tackiness at temperatures as high as 230° F. 6. Some stabilizers for vinyls tested as well as sodium acetate can be used to activate sulfur cures in 1,3-butadiene-acrylonitrile copolymer-Vinylite blends to formulate light-colored transparent products.

Alternating Copolymerization of Butadiene and Propylene

1972 ◽  
Vol 45 (6) ◽  
pp. 1532-1545 ◽  
Author(s):  
Junji Furukawa
Keyword(s):  
Low Temperature ◽  
Carbonyl Compounds ◽  
Catalyst Activity ◽  
Active Species ◽  
Alternating Copolymer ◽  
Synthetic Rubber ◽  
Monomer Feed ◽  
Alternating Copolymerization ◽  
Titanium Compounds ◽  
Anionic Copolymerization

Abstract An alternating copolymer of propylene and butadiene is prepared with vanadium or titanium compounds and alkylaluminum compounds as the polymerization catalyst. The catalyst should be prepared at extremely low temperature as −70° C and halogen atom is essential to the catalyst activity. Carbonyl compounds such as ketone, acid, ester, acid anhydride, and acid peroxide are very effective additives to the catalyst for enhancement of the molecular weight of the polymer. Potentiometric titration and the ESR studies suggest that a divalent vanadium compound associated to form the dimer through a chloride bridge is a precursor of the active species. An anionic copolymerization mechanism involving the alternating coordination of monomers is proposed. The copolymer is always of a 1:1 composition irrespective of the composition of monomer feed and the alternating structure of trans-1,4-poly (butadiene co propylene) is estimated from IR and NMR data. The copolymer seems to be a new versatile synthetic rubber having excellent low temperature properties, high rebound, good compatibility with conventional rubbers, and high resistance toward aging.

Compounding of cis-1,4 Polybutadiene for Tire Applications

1962 ◽  
Vol 35 (2) ◽  
pp. 546-557
Author(s):  
R. J. Brown ◽  
R. B. Knill ◽  
J. F. Kerscher ◽  
R. V. Todd
Keyword(s):  
Low Temperature ◽  
Operating Temperature ◽  
Dual Role ◽  
Laboratory Studies ◽  
Synthetic Rubber ◽  
Temperature Performance ◽  
Truck Tires ◽  
Tire Testing ◽  
Low Temperature Performance

Abstract cis-1,4-Polybutadiene is proving to be one of the most versatile compounding materials available to the tire compounder. It has characteristics as a polymer which make it acceptable as a replacement for either natural or synthetic rubber in tire applications. The successful use of cis-polybutadiene in this dual role, however, is dependent upon discovering its peculiarities and sensitivities and then exploiting them in that area of the tire where they are most applicable. Laboratory studies, confirmed by over three million miles of tire testing, have shown that in either passenger or truck tires the carcass durability can be substantially improved, operating temperature lowered, low temperature performance improved, and treadwear resistance increased when cis-PBD is properly used in the respective tire components.

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