Rubber elongation

Figure 7. Green strength of different rubbers. Elongation rate, 0.3 m/min compound, 55 parts carbon black N 330 NR, natural rubber IR, synthetic cis-1,4-...

In tensile testing of rubber, elongation is the increase in the distance between bench marks on a dumbbell strip or the distance apart of the grips holding a ring test piece, on the application of a load to the test sample. It is expressed as a percentage of the original distance between the marks. 

Rubber also contains almost entirely Z double bonds. Consistent with this fact is the finding that the prenyltransferases catalyzing formation of rubber promote loss of the pro-R proton rather than the pro-S proton of mevalonic acid (see Eq. 22-2). There appear to be two types of prenyltransferase in animal mitochondria giving rise to E and Z double bonds, respectively.64 In contrast, the rubber tree contains a 137-residue protein, the rubber elongation factor. This small protein binds to E prenyltransferases causing them to form Z double bonds.65 The bacterium Micrococcus hit cits synthesizes all E polyprenyl alcohol diphosphates up to the 0 5 nonaprenyl compound solanesyl diphosphate.66... 

Rubber Elongation Factor Radio Frequency Identification ring opening polymerisation... 

Light, D. R., R. A. Lazarus, and M. S. Dennis, Rubber elongation by famesyl pyrophosphate synthases involves a novel switch in enzyme specificity, J. Biol. Chem., 264, 18598-18607 (1989). 

Abraham et al. reported that films of pre-vulcanized NR nanocomposite were fabricated by casting and evaporating a mixture of NR latex and aqueous suspension of cellulose nanofibrils (CNF). By this method, the CNF were evenly distributed in the NR composites. The increase of CNF content in the NR matrix caused the increasing the Young s modulus and tensile strength of materials, but the decreasing characteristic rubber elongation. The enhancements in mechanical and dynamic mechanical properties were attributed to the formation of a Zn ellulose complex and the three dimensional network of the CNF in the NR matrix as a result of the deprotonation of the cellulose. 

The production of crystals in a polymer by the action of stress, usually in the form of an elongation. It occurs in fiber spinning, or during rubber elongation, and is responsible for enhanced mechanical properties. Simultaneous readings of load and deformation, converted to stress and strain, plotted as ordinates and abscissas, respectively, to obtain a stress-strain diagram. 

Alenius H, Kalkkinen N, Turjanmaa K, Makinen-Kiljunen S, Reunala T, Palosuo T (1996b) Significance of rubber elongation factor as a latex allergen. Int Arch Allergy Immunol 109 362-368... 

Apparent molecular weight based on electrophoretic mobility. C complete amino acid sequence known P partial sequence known REF rubber elongation factor... 

Prohevein C-domain Rubber elongation factor Prohevein... 

Czuppon AB, Chen Z, Rennert S, Engelke T, Meyer HE, Heber M, Baur X (1993) The rubber elongation factor of rubber trees... 

De Corres L, Moneo I, Munoz D, Bernaola G, Fernandez E, Audicana M, Urrutia I (1993) Sensitization from chestnuts and bananas in patients with urticaria and anaphylaxis from contact with latex. Ann Allergy 70 35-39 Dennis M, Henzel W, Bell J, Kohr W, Light D (1989) Amino acid sequence of rubber elongation factor protein associated rubber particles in Hevea latex. J Biol Chem 264 18618-18626 Forstrom L (1980) Contact urticaria from latex surgical gloves. Contact Dermatitis 6 33-34... 

Fresh natural rubber latex contains 1-2% of proteins. The total protein content can be estimated by the semi-micro Kjeldahl method using the formula nitrogen content x 6.25. When a field natural rubber latex is centrifuged, about one-quarter of these proteins is adsorbed on the surface of rubber particles, another quarter in the bottom fraction and half of them in the serum fraction. The serum phase of natural rubber latex has been shown to contain proteins different from those of rubber particles in terms of their molecular weights, with those in the serum phase fall in the region of 6 to more than 200 kDa, while the major proteins of rubber particles are 14.5 and 29 kDa, which are similar to rubber elongation factor and hevamines, respectively. ... 

Czuppon, A.B., Chen, Z., Rennert, S., Engelke, T., Meyer, H.E., Heber, M. and Baur, X., The rubber elongation factor of rubber trees (Hevea brasiliensis) is the major allergen in latex. J. Allergy Clin. Immunol, 92, 690-697 (1993). 

Diirauer, A., Csaszar, E., Mechtler, K., Jungbauer, A. and Schmid, E., Characterisation of the rubber elongation factor from ammoniated latex by electrophoresis and mass spectrometry. J. Chromatogr. A, 890, 145-158 (2000). 

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