Strength of Amorphous and of Crystallizing Rubberlike Polymers

1946 ◽  
Vol 19 (1) ◽  
pp. 42-45 ◽  
Author(s):  
A. P. Aleksandrov ◽  
J. S. Lazurkin

Abstract The strengths of unloaded vulcanizates and the action of active fillers differ greatly according to the types of elastomers from which they are derived. These differences are not connected directly with the chemical compositions of the elastomers. Thus, for example, vulcanizates of natural rubber and synthetic isoprene rubber differ in strength in the ratio 10–15 to 1, whereas vulcanizates of Butyl rubber and of polychloroprene are very similar to natural rubber vulcanizates with respect to tensile strength. These differences in tensile strength cannot be ascribed directly to differences in structure of the chains, linear or branched; linear polymers of styrene and of methyl methacrylate “vulcanized” by small admixtures of butadiene-benzene or dimethacrylate-ethyleneglycol have, in the elastic state, tensile strengths which are just as low as those of unloaded vulcanizates of sodium-butadiene rubber or of isoprene rubber. The differences in tensile strength must, accordingly, be looked for in the different macroscopic properties of these polymers.

2020 ◽  
Vol 26 (2) ◽  
pp. 62-69
Author(s):  
Farida Ali ◽  
Tuti I. Sari ◽  
Andi A. Siahaan ◽  
Al-Kautsar D. Arya ◽  
Tri Susanto

Penelitian ini untuk mengetahui pengaruh penambahan Natural Rubber (NR) dan Epoxidation Natural Rubber (ENR-46) dengan kompatibiliser Chlorprene Rubber (CR) pada aplikasi kompon termoplastik Poly Vinyl Chloride (PVC) dan Nitrile Butadiene Rubber (NBR), variabel penelitian meliputi ENR-46/PVC/NBR/CR, NR/PVC/NBR/CR dan CR-NR/PVC/NBR, CR-ENR-46/PVC/NBR. Parameter pengujian sifat fisik-mekanik : Hardness (Shore A), Tensile Strength (Mpa), Elongation at Break (%) dan ketahanan terhadap pelarut minyak (n-Pentane, Toluene, Hexane dan Pertalite). Hasil penelitian didapatkan untuk sifat fisik-mekanik, semakin banyak penambahan NR Kekerasan kompon termoplastik akan menurun, Tensile Strength dan Elongation at Break kompon akan meningkat begitu juga dengan CR-NR. Tetapi berbanding terbalik hasilnya untuk ENR-46 dan CR-ENR-46. Pengujian Ketahanan terhadap pelarut minyak semakin banyak penambahan ENR-46 Ketahanan kompon termoplastik terhadap pelarut akan meningkat, hasil yang sama juga pada CR-ENR-46. Tetapi berbanding terbalik hasilnya dengan penambahan NR dan CR-NR pada kompon termoplastik.


1956 ◽  
Vol 29 (1) ◽  
pp. 99-105 ◽  
Author(s):  
G. F. Bloomfield ◽  
F. M. Merrett ◽  
F. J. Popham ◽  
P. Mc L. Swift

Abstract Graft polymers result when vinyl monomers are polymerized in the presence of natural rubber, either in solution or as latex, and some of the polymeric chains become attached to the rubber molecules. The properties of the natural rubber can be widely modified according to the nature and the amount of the grafted polymer. The polymer-modified natural rubber appears to be produced by direct growth of polymer chains on to rubber molecules rather than by a transfer reaction involving the rubber. Graft polymers of styrene and methyl methacrylate with natural rubber can be compounded and cured to give light-colored articles of good tensile strength, and rubber-methyl methacrylate graft polymers have outstanding flex-cracking and fatigue resistance.


1999 ◽  
Vol 72 (4) ◽  
pp. 721-730 ◽  
Author(s):  
G. R. Hamed ◽  
J. Zhao

Abstract Typical sulfur-cured vulcanizates of styrene-butadiene rubber (SBR) and natural rubber (NR) were prepared, and subjected to air-oven aging at 100 °C. Gum specimens exhibited an initial aging period in which stiffness was unchanged, while tensile strength and strain-to-break were significantly reduced. In contrast, black-filled vulcanizates stiffened during early aging. After intermediate aging times, NR specimens softened, while SBR stiffened. With prolonged aging, all compositions became hard and inextensible.


2017 ◽  
Vol 44 (5) ◽  
pp. 25-28 ◽  
Author(s):  
A.A. Zuev ◽  
L.R. Lyusova ◽  
N.P. Boreiko

Now there is not a single area of industry that can do without adhesive elastomer materials. Composites based on synthetic rubbers comprise 75% of the total volume of adhesive materials produced, which is due to the combination of unique properties typical of the elastomer base of the adhesive. The base of many imported adhesives for the bonding of rubber to metal is chlorinated natural rubber. As an alternative, chlorinated synthetic isoprene rubber has been proposed, developed at the Scientific Research Institute for Synthetic Rubber in St Petersburg. The chlorinated isoprene rubber was compared with imported chlorinated natural rubber in adhesive composites, and the physicomechanical properties of mixes based on a blend of chlorinated rubber and nitrile butadiene rubber were investigated. The investigation was conducted on chlorinated natural rubber of grade Pergut S20, chlorinated isoprene rubber SKI-3, and nitrile butadiene rubbers of grades BNKS-28AMN and SKN-26S. The influence of the ratio of chlorinated rubber to nitrile butadiene rubber and the technological factors of mix preparation on the properties of films produced from them was established. It was shown that, in terms of the level of properties, home-produced chlorinated rubber can be used as the base for adhesives for hot bonding of rubber to metal instead of imported Pergut S20.


2016 ◽  
Vol 705 ◽  
pp. 35-39 ◽  
Author(s):  
Bryan B. Pajarito ◽  
Jimyl Arabit

Tensile properties of surfactant-loaded natural rubber (NR) vulcanizates are investigated in correlation with blooming. Rubber sheets are compounded using an L12 orthogonal array of Taguchi design of experiment, where ingredients are treated as factors varied at low and high loadings. Blooming experiments are carried out by placing NR sheets in a natural convection oven set at 50 °C for 20 days. The amount of bloom on the surface is removed using adhesive tape and is monitored with time. Tensile properties of rubber dogbone samples are also measured with time. Results show that 5 out of 12 formulations show blooming to be significantly related to tensile modulus (0.005 < p < 0.039). It is observed that the tensile modulus increases with blooming (0.898 < r < 0.973). Three formulations indicate significant correlation of blooming with tensile strength (0.022 < p < 0.047). As observed, tensile strength decreases with blooming (-0.884 < r < -0.930). Five formulations signify blooming to have significant correlation with maximum tensile strain (0.000 < p < 0.011), which decreases with blooming (-0.957 < r < -0.995). Two formulations imply significant negative (-0.960 < r < -0.963) correlation between blooming and tensile set (p= 0.009).


2010 ◽  
Vol 150-151 ◽  
pp. 762-765
Author(s):  
Ji Hu Wang ◽  
Hong Bo Liu ◽  
Shao Guo Wen ◽  
Yan Shen

Attapulgite (AT)/natural rubber (NR)/ styrene-butadiene rubber (SBR) nanocomposites have been prepared after attapulgite was modified by different coupling agent. The treatment of AT caused the adhesion between AT nanorods and the nature rubber/styrene-butadiene rubber was improved, which enhanced the tensile properties of the matrix. The tensile strength of composites attained 15.6 MPa after AT was modified by 3%wt Si-69 coupling with addition of 20 phr.


2014 ◽  
Vol 716-717 ◽  
pp. 70-73
Author(s):  
Yue Qiong Wang ◽  
Zheng Peng ◽  
Jie Ping Zhong ◽  
Kui Xu ◽  
Chang Jin Yang ◽  
...  

Natural rubber (NR)/epoxidized natural rubber (ENR)/carbon black (CB), natural rubber/butadiene rubber (BR)/carbon black and natural rubber/isobutylene-isoprene rubber (IIR)/carbon black compounds were prepared by mechanical mixing method. The mechanical properties, dynamic mechanical properties for the compounds were investigated respectively. The temperature range of tanδ>0.3 of NR/ENR40/CB compound was wider and shifted to high temperature than NR/CB compound. Comprehensive analysis indicated that NR/BR/CB and NR/IIR/CB compounds had no better damping performance than NR/CB compounds, while NR/ENR/CB compound had better damping performance.


1950 ◽  
Vol 23 (1) ◽  
pp. 1-8
Author(s):  
B. Dogadkin ◽  
B. Karmin

Abstract 1. In mixtures with a large content of constructive (vulcanizing) agent, the vulcanization-optimum phenomenon is connected with the formation of dense space-lattices in the structure of the vulcanizate, which inhibit the formation of crystalline or highly oriented segments during elongation. 2. In contrast to mixtures with a small content of vulcanization agent, the vulcanization optimum of which is explained by superimposition of oppositely directed constructive and destructive processes, the case noted in the preceding paragraph shows a maximum only on the kinetic curve representing the change in strength. The kinetic curves representing relative elongation, swelling, and solubility are monotonic in character. 3. The maximum on the kinetic curve representing the change in strength in mixtures with a large content of constructive agent occurs before complete combination of the latter with the rubber. 4. In consequence of the absence of oppositely directed actions on the part of sulfur and oxygen, the vulcanization of sodium-butadiene rubber mixtures shows a maximum only on the kinetic curves representing the change in strength. 5. The position of the strength maximum in mixtures with a large content of constructive agent depends on the rate of deformation. As the rate of deformation is decreased, the maximum appears after more prolonged vulcanization periods of the mixtures. 6. The strength of natural rubber vulcanizates at the vulcanization optimum is a linear function of the quantity of crystalline phase formed during elongation.


2014 ◽  
Vol 3 (2) ◽  
pp. 1-4
Author(s):  
Indra Surya ◽  
Siswarni MZ

By using a semi-efficient vulcanization system, the effect of Epoxidized Natural Rubber (ENR) as a compatibilizer in silica-filled Styrene Butadiene Rubber (SBR) compound was carried out. The ENR was incorporated into the silica-filled SBR compound at 5.0 and 10.0 phr. An investigation was carried out to examine the effect of ENR on cure characteristics and tensile properties of the silica-filled SBR compound. It was found that ENR gave enhanced cure rate to the silica-filled SBR compound. ENR also exhibited a higher torque difference, tensile modulus, and tensile strength up to 10.0 phr. The study of rubber - filler interaction proved that the addition of ENR to the silica-filled SBR system improved the rubber - filler interaction.


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