Effect of Low Temperatures on Young's Modulus of Elastomers

1944 ◽  
Vol 17 (2) ◽  
pp. 421-434
Author(s):  
John W. Liska

Abstract The data presented should be of value to the rubber technologist who may be called on to produce a compound having a given base polymer capable of performing satisfactorily down to a specified low temperature. Although natural rubber is basically more cold-resistant than some of the other synthetic elastomers, it has been found possible to add larger quantities of softeners and modifiers to the latter (without causing too serious a decrease in mechanical properties) than can be added to natural rubber. Consequently, it is possible to compound synthetic elastomer stocks having better low-temperature properties than natural rubber stocks. In the case of material which does not exhibit crystallization, it should be possible (either from experience or by a simple test at normal temperatures) to set an upper limit for the Young's modulus of the proposed stock consistent with satisfactory operation. A modulus vs. temperature curve of the stock would then indicate definitely whether the observed modulus at the specified low temperature exceeded the limit previously set. If it did not and, in addition, the brittle-point temperature was found to be below the specified operating temperature, successful operation could reasonably be expected. In general, it is not necessary to calculate Young's modulus in all cases. For a given load and sample size, the deflection as measured would serve equally well as an index.

2014 ◽  
Vol 803 ◽  
pp. 310-316 ◽  
Author(s):  
S.T. Sam ◽  
Nurul Hani ◽  
H. Ismail ◽  
Nik Noriman ◽  
S. Ragunathan

Natural fiber reinforced composites are increasingly being used in various applications area. Therefore, the processing method and physical properties of these composites are very important parameters in product quality and quaranty. This paper focused on the tensile properties, Fourier transform infrared (FTIR) and water absorption of cogon grass (CG) with low density polyethylene (LDPE)/soya spent flour (SSF) composites. The tensile strength and elongation at break (Eb) of uncompatibilized CG with LDPE/ SSF decreased significantly with increasing of fiber content. However, the Young’s modulus increased with increasing of CG loading. The presence of epoxidized natural rubber (ENR 50) as a compatibilizer increased the tensile strength, Eband Young’s modulus of the composites when compared to uncompatibilized composites. Fourier transform infrared results show distinguishable peaks for compatibilized and uncompatibilized composites. The water absorption for both uncompatibilized and compatibilized composites increased from day 1 until day 21. The presence of ENR 50 as compatibilizer showed lower water absorption percentage compared to uncompatibilized composites.


2018 ◽  
Vol 789 ◽  
pp. 221-225
Author(s):  
Nattapol Dedruktip ◽  
Wasan Leelawanachai ◽  
Nuchnapa Tangboriboon

Alumina fiber is a ceramic material used as a dispersed phase or filler to reinforce the mechanical and improve thermal properties of natural rubber via vulcanization process at curing temperature 150°C. The amount of alumina fiber added in natural rubber was varied from 0 to 50 phr on 100 phr of natural rubber in a sulfur curing system. Adding 10 phr alumina fiber affects to obtain the best natural rubber composite samples having good mechanical and thermal properties. Tensile strength, elongation at break, Young’s modulus and thermal conductivity of adding 10 phr whisker alumina fiber encoded NR-Al-10 are equal to 14.38±1.95 MPa, 1038.4±41.45%, 545.63±25.67 MPa and 0.2376±0.0003 W/m.K, respectively, better than those of pure natural rubber compounds without adding alumina fiber. Tensile strength, elongation at break, Young’s modulus and thermal conductivity of natural rubber without adding alumina fiber are equal to 14.06±6.03 MPa, 949.41±52.15%, 496.32±8.54 MPa and 0.2500±0.0003 W/m.K, respectively.


2008 ◽  
Vol 47-50 ◽  
pp. 427-430
Author(s):  
Yupaporn Ruksakulpiwat ◽  
Jatuporn Sridee ◽  
Nitinat Suppakarn ◽  
Wimonlak Sutapun

In this research, vetiver grass was used as a filler in polypropylene (PP) composite. Chemical treatment was done to modify fiber surface. Natural rubber (NR) and EPDM rubber at various contents were used as an impact modifier of the composites. The composites were prepared by using an injection molding. By adding NR or EPDM to PP composites, a significant increase in the impact strength and elongation at break was observed in PP composite with rubber content more than 20% by weight. However, the tensile strength and Young’s modulus of the composites decrease with increasing rubber contents. Nevertheless, the tensile strength and Young’s modulus of the composites with NR or EPDM are still higher than those of PP up to 10% and 20% rubber contents, respectively. Comparisons between NR and EPDM rubber on the mechanical properties of the composites were elucidated.


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