The Effect of Pile Bombardment on Uncured Elastomers

1949 ◽  
Vol 22 (1) ◽  
pp. 138-147 ◽  
Author(s):  
W. L. Davidson ◽  
I. G. Geib
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Mineral Content ◽  
Control Sample ◽  
Butyl Rubber ◽  
Alpha Particles ◽  
High Concentrations ◽  
Ionizing Radiations ◽  
Rubber Stock

Abstract Previous work on the effects of ionizing radiations on hydrocarbons has established that four competitive processes are usually operative: (1) dehydrogenation, (2) condensation or polymerization, (3) hydrogenation (action of nascent hydrogen on any unsaturated matter present), (4) decomposition (C—C cleavage). The chain reacting nuclear pile offers an ideal means for subjecting relatively thick samples of matter (such as rubber) to uniformly high concentrations of radiation. Such studies on natural rubber, Butyl rubber, and polyisobutylene allow one to draw the following conclusions. 1. Uncured natural rubber undergoes a slight curing action when exposed to pile radiations. 2. Polyisobutylene samples are appreciably degraded by pile radiations. 3. The same effects as noted in (1) and (2) are greatly enhanced by secondary alpha particles, produced by an (n, α) reaction on boron (milled into the elastomer). However, even a 2-hour bombardment of natural rubber yields a product greatly inferior to sulfur vulcanizates. 4. Pile bombardment does not introduce measurable unsaturation in polyisobutylene and decreases the unsaturation in natural rubber but slightly. 5. A typical Butyl rubber stock is permanently degraded by pile irradiation, showing on cure reduced tensile strength compared to that of a control sample. 6. Natural rubber shows a weak but measurable radioactivity days after bombardment, probably because of its mineral content. Polyisobutylene is not appreciably active.

scholarly journals Study the impact of A nanomixture of carbon black and clay on the mechanical properties of A series of irradiated natural rubber/ butyl rubber blend

2021 ◽  
Author(s):  
Dalal Alshangiti
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Theoretical Models ◽  
Butyl Rubber ◽  
Nano Particles ◽  
Vinyl Silane ◽  
Link Density ◽  
The Impact

Abstract A series of natural rubber/ butyl rubber NR/IIR blend loaded with N660 carbon black CB and triethoxy vinyl silane treated clay nano particles (TCNP) were prepared using gamma irradiation in the presence of polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). The effect of incorporating different content of N660 carbon black and 5 part per hundred of rubber (phr) of treated clay on the mechanical properties of the prepared nano composites have been investigated. The additions of TCNP into CB/ rubber composites markedly increase their tensile strength due to the increase of the cross-link density. These results indicated that the TCNP may be enclosed or trapped in the occluded structure of CB. The effect of CB and TCNP content on the tensile strength (σ), elongation at break (εb %) and modulus of elasticity (E, MPa) of natural rubber/ butyl rubber NR/IIR blend have been investigated. The incorporation of 5 phr of TCNP into 30 phr carbon black loaded NR/ IIR composites results in the increased tensile strength value by about 60%. Finally, theoretical models were used to interpret the experimental results.

scholarly journals Properties Characterization of Vulcanized Natural Rubber Filled with Uncarbonized Particulate Cow Bone

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Akinlabi Oyetunji ◽  
Isiaka O Bakare ◽  
Reginald Umunakwe ◽  
Adetola O Adeyemo
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Abrasion Resistance ◽  
Control Sample ◽  
Filler Loading ◽  
Rubber Composites ◽  
Compression Moulding ◽  
Natural Rubber Composites ◽  
Cow Bone

This work investigates the effects of addition of 63 µm uncarbonized particulate cow bone as fillers in vulcanized natural rubber on the tensile properties, hardness and abrasion resistance of the composites. Cow bones were procured from an abattoir, cleaned, crushed, pulverized, ball milled and sieved to obtain the particles that passed through the 63 µm mesh size. Natural rubber composites materials were prepared varying the filler loading as 5, 10, 15 and 20 pphr respectively. The compounded rubber samples were cured in a hot press using compression moulding technique. The control sample was produced using 20 pphr of carbon black. The cured rubber samples were conditioned at room temperature for two weeks before they were characterized. The tensile strength and elastic modulus of the samples filled with cow bone increased with filler loading up to 15 pphr before they started decreasing. Carbon black reinforced sample possessed higher tensile strength, modulus and hardness than the samples filled with uncarbonized particulate cow bone. The hardness for all samples maintained an increasing trend with increase in the filler loadings. Particulate cow bone reinforced natural rubber offered higher elongation than carbon black reinforced samples. At 10, 15 and 20 pphr, cow bone reinforced composites exhibited higher abrasion resistance than carbon black filled sample. The optimal filler loading of uncarbonized particulate cow bone reinforced natural rubber was 15 pphr.  Cow bone reinforced natural rubber can find applications in areas where moderate strength, hardness, elongation and wear resistance are required such as in protective footwear, bouncing balls and cases of children toys.Keywords— carbon black, cow bone, fillers, natural rubber, composites.

Effect of Degree of Elongation on Ozone Cracking of Rubbers

1959 ◽  
Vol 32 (1) ◽  
pp. 278-283
Author(s):  
Yu S. Zuev ◽  
S. I. Pravednikova
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Butyl Rubber ◽  
Objective Method ◽  
Rubber Sample ◽  
Rate Of Growth ◽  
Gutta Percha ◽  
Effective Depth

Abstract It is known from the literature that there exists a socalled critical elongation at which disruption of the structure of rubbers under the influence of ozone is most severe. However, the available data concerning this problem are fairly contradictory. According to a number of statements the critical elongation is observed in the case of vulcanizates of natural rubber, but its estimation by different authors varies from 5 to 50%. Some authors consider that a critical elongation exists in the case of synthetic rubbers susceptible to attack by ozone, while others consider that no such characteristic exists. It is said that polychloroprene and butyl rubber do not possess this characteristic. However, none of these data can be regarded as reliable since in most cases ozone cracking of the rubbers was characterized by arbitrary methods, as a rule by the “degree of cracking” expressed by the number of marks. We have carried out a detailed investigation of the effect of the degree of elongation on ozone cracking of rubbers, the rate of growth of cracks being determined by an objective method based on the effective depth of the cracks calculated from the decrease of stress in the relaxed rubber sample when exposed to the action of ozone. The following rubbers—NK, SKS, neurite, SKN, and SKB were investigated in standard formulas, at optimum true tensile strength. Gutta-percha (elastic vulcanizate) and butyl rubber compositions in phr were: gutta-percha 100, MBT 0.8, sulfur 5; butyl rubber 100, stearine 3, MBT 0.65, thiuram disulfide 1.3, zinc oxide 5, sulfur 2.

scholarly journals Impact of a nanomixture of carbon black and clay on the mechanical properties of a series of irradiated natural rubber/butyl rubber blend

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 662-670
Author(s):  
Dalal M. Alshangiti
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Theoretical Models ◽  
Butyl Rubber ◽  
Clay Nanoparticles ◽  
Vinyl Silane ◽  
Link Density ◽  
Cross Link Density

Abstract A series of natural rubber/butyl rubber NR/IIR blend loaded with N660 carbon black (CB) and triethoxy vinyl silane treated clay nanoparticles (TCNPs) were prepared using gamma irradiation in the presence of a polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). The effect of incorporating different contents of N660 CB and five parts per hundred of rubber (phr) of treated clay on the mechanical properties of the prepared nanocomposites has been investigated. The addition of TCNP to CB/rubber composites markedly increase their tensile strength due to the increase of the cross-link density. These results indicated that the TCNP may be enclosed or trapped in the occluded structure of CB. The effect of CB and the TCNP content on the tensile strength (σ), elongation at break (ε b, %), and modulus of elasticity (E, MPa) of natural rubber/butyl rubber NR/IIR blend have been investigated. The incorporation of 5 phr of TCNP into 30 phr CB-loaded NR/IIR composites results in the increased tensile strength value by about 60%. Finally, theoretical models were used to interpret the experimental results.

Ozone Resistance of Rubber Insulations

1959 ◽  
Vol 32 (4) ◽  
pp. 1104-1116
Author(s):  
W. H. Couch ◽  
G. H. Hunt ◽  
O. S. Pratt
Keyword(s):  
Natural Rubber ◽  
Corona Discharge ◽  
Atomic Oxygen ◽  
Constant Load ◽  
Butyl Rubber ◽  
Surface Coatings ◽  
High Voltage Insulation ◽  
High Concentrations ◽  
Low Pressures ◽  
Ozone Resistance

Abstract The results of experiments on the ozone and corona cutting of rubber high voltage insulation show that the relaxation of mechanical stress in the insulation plays an important role. Studies were made to establish the stress decay characteristics of various formulations based on natural rubber, SBR and butly rubber. A method was developed for correlating the stress decay and ozone resistance characteristics which permits the performance of bent samples of any formulation to be predicted at ozone concentrations up to 0.2%. Comparisons were made between the cutting in an intense corona discharge and that in high concentrations of ozone outside of the discharge. These comparisons show that the results of ozone tests at constant load together with stress relaxation tests may be used to predict the performance of rubber insulation in corona discharge. Tests were carried out in the products of corona discharge at pressures less than atomospheric. These tests lead to the conclusion that at very low pressures (ca. 1 mm Hg) cutting is caused not by ozone but by atomic oxygen. Compounds based on a variety of polymers were exposed to atomic oxygen and it was found that butyl rubber cuts rapidly in atomic oxygen while natural rubber, SBR, neoprene, and Hypalon do not. Antioxidants do not protect butyl rubber against cutting in atomic oxygen, but surface coatings were found to offer protection.

Strength of Amorphous and of Crystallizing Rubberlike Polymers

1946 ◽  
Vol 19 (1) ◽  
pp. 42-45 ◽  
Author(s):  
A. P. Aleksandrov ◽  
J. S. Lazurkin
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Butyl Rubber ◽  
Chemical Compositions ◽  
Butadiene Rubber ◽  
Linear Polymers ◽  
Elastic State ◽  
Natural Rubber Vulcanizates ◽  
Isoprene Rubber

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.

Tensile Strength of Protein-free Natural Rubber and its Vulcanizate Soaked in Water

2020 ◽  
Vol 93 (9) ◽  
pp. 293-299
Author(s):  
Luu Thanh HUYEN ◽  
Chen Ao RAN ◽  
Yoshimasa YAMAMOTO ◽  
Seiichi KAWAHARA
Keyword(s):  
Tensile Strength ◽  
Natural Rubber

Pengaruh penambahan natural rubber (NR), epoxidation natural rubber (ENR-46) dan chlorprene rubber (CR) pada sifat kompon termoplastik

2020 ◽  
Vol 26 (2) ◽  
pp. 62-69
Author(s):  
Farida Ali ◽  
Tuti I. Sari ◽  
Andi A. Siahaan ◽  
Al-Kautsar D. Arya ◽  
Tri Susanto
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Vinyl Chloride ◽  
Butadiene Rubber ◽  
Elongation At Break ◽  
Nitrile Butadiene Rubber ◽  
Poly Vinyl Chloride

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.

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

scholarly journals Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

2021 ◽  
Vol 22 (6) ◽  
pp. 3150
Author(s):  
Anna Masek ◽  
Stefan Cichosz ◽  
Małgorzata Piotrowska
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Poly Lactic Acid ◽  
Uv Aging ◽  
High Elasticity ◽  
Natural Fillers ◽  
Natural Additives

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.

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