A Study of Mechanical and Optical Properties of an Alternating NBR and an Emulsion NBR

1973 ◽  
Vol 46 (5) ◽  
pp. 1264-1273 ◽  
Author(s):  
U. P. Mukherjee ◽  
C. Goldstein
Keyword(s):  
Tensile Properties ◽  
Ultimate Strength ◽  
Dynamic Properties ◽  
Dicumyl Peroxide ◽  
Ultimate Elongation ◽  
Alternating Copolymer ◽  
Strain Data ◽  
Strain Induced Crystallization ◽  
Increased Strength ◽  
Induced Crystallization

Abstract At low elongation, over the range of temperatures and frequencies studied, the dynamic properties (elastic modulus and loss factor) and activation energy for the glass-rubber transition are the same for highly alternating and emulsion copolymers of acrylonitrile and butadiene. At higher elongation the stress-birefringence and x-ray data on cured (1.7 phr dicumyl peroxide) highly alternating copolymer show the occurrence of strain-induced crystallization, whereas the emulsion copolymer does not crystallize under strain. The stress-strain data for the highly alternating copolymer cured at 1.7 phr dicumyl peroxide and for the emulsion copolymer cured at 1.7 phr and 0.8 phr show that at 1.7 phr dicumyl peroxide the highly alternating copolymer has higher ultimate strength. However, the emulsion copolymer cured by 0.8 phr dicumyl peroxide shows tensile properties similar to those of the highly alternating copolymer cured by 1.7 phr dicumyl peroxide. Therefore, it may be concluded that the increased strength and ultimate elongation of highly alternating copolymer, as reported by Furukawa, are due to the fact that at the same curative level the emulsion copolymer gets over-cured resulting in lower ultimate strength and elongation. This present study indicates that it is not appropriate to compare the ultimate properties of the emulsion and highly alternating copolymers cured at the same level of dicumyl peroxide. Slight adjustment in curing condition brings highly alternating and emulsion copolymers closer in tensile strength and ultimate elongation. In conclusion, it may be said that this study indicates that highly alternating NBR shows tensile properties similar to those obtained for emulsion NBR already produced commercially.

Ultimate Properties of Stereoregular and Stereoirregular 1,4-Polybutadiene Networks and Their Correlation with Theories

1994 ◽  
Vol 67 (1) ◽  
pp. 88-106
Author(s):  
M. A. Sharaf
Keyword(s):  
Ultimate Strength ◽  
Chemical Structure ◽  
Intrinsic Property ◽  
Primary Role ◽  
Physical Processes ◽  
Ultimate Properties ◽  
Different Temperatures ◽  
Strain Induced Crystallization ◽  
Induced Crystallization ◽  
Maximum Extensibility

Abstract The ultimate properties of stereoregular and stereoirregular 1,4-polybutadiene (PB) networks covering a range in micro-chemical structure (cis-trans-vinyl) have been investigated. The dependence of the ultimate properties, namely the ultimate strength and the maximum extensibility, on sterochemical structure, has been demonstrated at different temperatures. Also, dependence of the ultimate properties on temperature has been apparent. Focusing special attention on the physical processes that culminate in rupture of the network, confirmed and extended the primary role played by strain-induced crystallization. More specifically, strain-induced crystallization enhances attainment of greater values of strength and extensibility. Noncrystallizable elastomers were found to have lower ultimate properties due to the absence of rupture-impeding mechanisms and consequently they become incapable of reaching their maximum extensibility. The frequently observed maximum in plots of the ultimate strength fr vs. the molecular mass Mc has been verified as an intrinsic property of the networks. This property was found to depend on the degree of crosslinking, rather than being time dependent. Values of the ultimate strength fr of both crystallizable and noncrystallizable networks were well reproduced by Bueche's theory of rupture. On the other hand, the Griffith criteria were found to have some success with noncrystallizable networks. Calculated values of the threshold surface free energy G0 were in agreement with those reported in the literature for similar noncrystallizable networks.

Influence of Dicumyl Peroxide and Maleic Anhydride on the Tensile Properties of HDPE–Calcium Carbonate Composites

2011 ◽  
Vol 239-242 ◽  
pp. 1349-1352
Author(s):  
Rui Bao Guo ◽  
Jin Shui Yao ◽  
Zhi Yong Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Maleic Anhydride ◽  
Stearic Acid ◽  
Tensile Properties ◽  
Dicumyl Peroxide ◽  
Yield Strain ◽  
Ultimate Elongation ◽  
Inorganic Matter

PE is modified basically with inorganic matter (generally CaCO3) and some auxiliaries, but because of the interattraction of the particles, CaCO3is easy to agglomerate, so we must add some dispersants(generally stearic acid ) ,but some study suggested that, with stearic acid , tensile strength, yield strain and ultimate elongation reduced. But we find that adding dicumyl peroxide and Maleic Anhydride can make up for the defects even increase these properties. As initiator and crosslinker ,dicumyl peroxide is usually used in synthesis of polymers. And is also Maleic Anhydride. However,in this experiment, we add a certain amount of them, dicumyl peroxide initiated Maleic Anhydride to ingraft, also,it initiated the molecular chains of PE to be cross-linked. So, the tensile properties of HDPE–calcium carbonate composites increased obviously, nevertheless ,we must add appropriate amount, if exceeded ,the mechanical properties would reduce.

Reconstructing the mechanical response of polybutadiene rubber based on micro-structural evolution in strain-temperature space: entropic elasticity and strain-induced crystallization as the bridges

Soft Matter ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 447-455 ◽  
Author(s):  
Pinzhang Chen ◽  
Yuanfei Lin ◽  
Jingyun Zhao ◽  
Lingpu Meng ◽  
Daoliang Wang ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Structural Evolution ◽  
Entropic Elasticity ◽  
Polybutadiene Rubber ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Micro-structural evolution of polybutadiene rubber in strain-temperature space, and the reconstruction of the macro-mechanical response.

Strain-induced crystallization behaviour of natural rubbers from guayule and rubber dandelion revealed by simultaneous time-resolved WAXD/tensile measurements: indispensable function for sustainable resources

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 95601-95610 ◽  
Author(s):  
Yuko Ikeda ◽  
Preeyanuch Junkong ◽  
Takumi Ohashi ◽  
Treethip Phakkeeree ◽  
Yuta Sakaki ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Crystallization Behaviour ◽  
Time Resolved ◽  
Sustainable Resources ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Guayule and rubber dandelion natural rubbers are useful alternatives forHeveanatural rubber in terms of their strain-induced crystallization behaviours.

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