The effect of strain-induced crystallization on the ultimate properties of an elastomeric polymer network

1979 ◽  
Vol 19 (6) ◽  
pp. 409-413 ◽  
Author(s):  
James E. Mark
Keyword(s):  
Polymer Network ◽  
Ultimate Properties ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

The Effects of Cross-Linking and Strain on the Glass Transition Temperature of a Polymer Network

1980 ◽  
Vol 53 (4) ◽  
pp. 982-987 ◽  
Author(s):  
M. A. Sharaf ◽  
J. E. Mark
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymer Network ◽  
Thermal Shrinkage ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
Increase With Increase ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Abstract The glass transition temperature Tg of an elastomer is of great importance with regard to its utilization since at this temperature and below, the material can no longer exhibit rubberlike behavior. In the present study, networks were prepared from atactic poly(vinyl acetate) and poly(isobutyl methacrylate), both types of networks being inherently non-crystallizable and therefore immune from complications associated with strain-induced crystallization. The values of Tg were obtained by dilatometry, differential scanning Calorimetry, the measurement of viscoelastic losses, and irreversible thermal shrinkage. For both types of networks, Tg was found to increase with increase in degree of crosslinking and with increase in elongation. These results suggest that the most important effect of crosslinking and network elongation is a decrease in the mobility or entropy of the network chains.

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.

Effect of Strain-Induced Crystallization on the Elastomeric Properties of Cis-1,4-Polybutadiene Networks

1978 ◽  
Vol 51 (2) ◽  
pp. 285-296 ◽  
Author(s):  
T-K. Su ◽  
J. E. Mark
Keyword(s):  
Polymer Network ◽  
Polymer Networks ◽  
Experimental Studies ◽  
Anomalous Behavior ◽  
Critical Examination ◽  
Complete Suppression ◽  
Stress Strain ◽  
Strain Induced Crystallization ◽  
Alternative Suggestion ◽  
Induced Crystallization

Abstract Polymer networks, when studied at very high elongations, frequency show anomalous stress-strain isotherms in that they exhibit values of the modulus or “reduced force” [ƒ*] which increase markedly with increasing elongation. Such isotherms depart appreciably from the form predicted by the molecular theories of rubberlike elasticity and from the Mooney—Rivlin representation adopted from phenomenological arguments as well. For this reason, the interpretation of the increase in [ƒ*] at high elongations has been of great interest for a considerable period of time. For several decades now, this behavior has generally been attributed to the limited extensibility of the network chains. Critical examination of various published results pertinent to this question, in conjunction with more definitive experimental studies reported recently, however, support the alternative suggestion that such atypical isotherms are due to strain-induced crystallization. One experiment particularly relevant to this issue is the study of the stress-strain isotherms of a polymer network as a function of temperature. Such experiments have been carried out on natural rubber, but the relatively poor thermal stability of this polymer and the extent to which its melting point is increased by elongation make it essentially impossible to study the high elongation stress-strain relationships for this polymer at a temperature sufficiently high to ensure complete suppression of strain-induced crystallinity. Similar experiments carried out on networks of a more suitable polymer, polyisobutylene, gave stress-strain isotherms showing the upturn in the reduced force at low temperature, but not at higher temperatures, thus strongly implicating strain-induced crystallization as the origin of this anomalous behavior. These experiments, however, suffered somewhat from the one shortcoming that the increase in temperature required to suppress the upturn in [ƒ*] also decreased the maximum extensibility of the network to below the elongation at which the upturn occurred at the lower temperatures.

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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