EFFECT OF CURE EFFICIENCY ON PROPERTIES OF GUM AND BLACK FILLED NATURAL RUBBER VULCANIZATES

2011 ◽  
Vol 84 (2) ◽  
pp. 229-242 ◽  
Author(s):  
Gary R. Hamed ◽  
Kanoktip Boonkerd
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Cure Time ◽  
Cracking Pattern ◽  
Natural Rubber Vulcanizates ◽  
Scanning Electron ◽  
Fracture Specimens ◽  
Strength Effect

Abstract Effects of the sulfur cure efficiency on the reversion behavior and the normal and edge-cut tensile strength of gum and black filled natural rubber (NR) vulcanizates were studied. N, N-dicyclohexyl-2-benzothiazole sulfenamide (DCBS) was used as an accelerator. A series of five vulcanizates with high to low cure efficiencies was prepared by increasing the sulfur (S) to DCBS ratios within the range of 0.26–6.66. All vulcanizates were formulated to have the same crosslink density. The degree of reversion (%) calculated from cure curves of gum and black filled NR at 20 min above the cure time (tc100) passed through maximum with decreasing cure efficiencies. For both gum and black filled NR, the highest degree of reversion (%) was observed at the S/DCBS ratio of 1.17. The normal tensile strengths of gum and black filled NR were directly proportional to the cure efficiency. For gum NR vulcanizates, the edge-cut tensile strength was markedly influenced by cure efficiency. Similar to the normal tensile strength, the gum NR vulcanizates cured with the lowest cure efficiency showed the lowest edge-cut tensile strength. Effect of the cure efficiency on the edge-cut tensile strength was less in the case of black filled NR vulcanizates. However, the black filled NR vulcanizates cured with the lowest cure efficiency also showed the lowest edge-cut tensile strength. The cut tip characteristics of the fracture specimens were investigated using scanning electron microscopy. The gum specimens showed only the simple lateral cracking pattern, while all black filled specimens showed the longitudinal cracking pattern. Four different cracking patterns of the black filled specimens were identified. The distribution of cracking patterns depended strongly on the size of precut and the cure efficiency.

Mechanical and Morphological Properties of Sulfur-Cured Natural Rubber/Polyethylene/Epoxidized Natural Rubber Blends

2017 ◽  
Vol 757 ◽  
pp. 14-18
Author(s):  
Kritsada Phatcharasit ◽  
Wirach Taweepreda ◽  
Patompong Phummor
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Morphological Properties ◽  
Rubber Blends ◽  
Compression Set ◽  
Internal Mixer ◽  
Scanning Electron

The polymer blend was prepared from natural rubber (NR) and polyethylene (PE) powder blended with epoxidized natural rubber (ENR) by using an internal mixer. In this study, epoxidized natural rubber (ENR) was used as compatibilizer for the blends. Blending ENR with PE powder and NR were prepared at various compositions from 0-20% by weight. Then, specimens from the blends were produced by compression molding at 150 °C. The mechanical and morphological properties of the composites were investigated. It was found that the addition of ENR content has improved the tensile strength, compression set and hardness for the ternary compositions composed of NR/PE powder/ENR compared to the binary one (i.e. NR/PE powder). ENR contributed to a better dispersion between the NR and PE phases as observed in the scanning electron microscopy.

Ridge Formation during the Abrasion of Elastomers

1982 ◽  
Vol 55 (4) ◽  
pp. 1055-1062 ◽  
Author(s):  
A. K. Bhowmick
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Natural Rubber ◽  
Crack Growth ◽  
Unit Length ◽  
Crack Growth Resistance ◽  
Small Particles ◽  
The Matrix ◽  
Natural Rubber Vulcanizates ◽  
Scanning Electron

Abstract Scanning electron microscopy studies have been carried out on gum and filled natural rubber vulcanizates to investigate the ridge formation in the abrasion of elastomers. The first step of the ridge formation is the occurrence of small particles on the smooth abrading surface by a process of microtearing. Their size and shape depend upon the frictional force per unit length of the abrader in contact with the rubber and the nature of the rubber and the abrasive. These particles are not loose, and, hence, are not removed easily if the strength of the matrix is high. Further particles appear on the surface with continued abrasion. These particles coalesce to form fine ridges on the surface which become progressively thicker. Removal of these ridges depends upon the crack growth resistance and strength of the vulcanizate as well as on the dissipation of sliding energy in the matrix. Gum and filled natural rubber vulcanizates follow similar mechanisms of ridge formation. Due to low strength and crack growth resistance of the gum natural rubber, the abrasion resistance is poor compared to the filled ones.

scholarly journals PENGARUH PENAMBAHAN ALKANOLAMIDA TERHADAP KARAKTERISTIK PEMATANGAN DAN KEKERASAN VULKANISAT KARET ALAM BERPENGISI SILIKA

2012 ◽  
Vol 1 (2) ◽  
pp. 7-10
Author(s):  
Harry Laksana Tampubolon ◽  
Darwis Syarifuddin Hutapea ◽  
Indra Surya
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Palm Oil ◽  
Crosslink Density ◽  
Cure Characteristics ◽  
System A ◽  
Cure Time ◽  
Oil Derivatives

By using a semi-efficient sulfur accelerated vulcanization system, a research about the effect of  the alcanolamide on cure characteristics and hardnes propertiess of natural rubber filled silika and alkanolamide been done. Alcanolamide produced from palm oil derivatives reacted with dietanolamine. Alcanolamide aaded  into  rubber  with levels 1.0, 3.0; 5.0; 7.0; 9.0; phr. It was found that  alcanolamide gave shorter  Scorch time and cure time. Alkanolamide also exhibited higher torque different, tensile moduli, tensile strength, and crosslink density up to  5.0 phr and ten decrease with future increaseing addition of alcanolamide.

The Effect of Different Sizes "Batu Reput" (Dolomite) as a Filler in SMR L and ENR-50

2013 ◽  
Vol 795 ◽  
pp. 383-387 ◽  
Author(s):  
J.N.M. Ridhwan ◽  
N.Z. Noimam ◽  
M.A.A. Mohd Salleh ◽  
S.T. Sam ◽  
L. Musa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Epoxidized Natural Rubber ◽  
Morphological Properties ◽  
Elongation At Break ◽  
Matrix Interaction ◽  
Scanning Electron

The effects of different sizes of Batu Reput (Dolomite) filler which are smaller size (<63μm) and bigger size (75-150μm) on tensile and morphological properties of Batu Reput (Dolomite) filled SMR L and epoxidized natural rubber (ENR-50) blends were investigated. Results indicated that, the tensile properties, such as tensile strength (TS), elongation at break (Eb) and stress at 100% elongation (M100) of Batu Reput (Dolomite) filled SMR L higher than Batu Reput (Dolomite) filled ENR-50 blends, particularly, at 15 phr of smaller size of Batu Reput (Dolomite). The scanning electron microscopy studies proved, Batu Reput (Dolomite) filled SMR L illustrated a higher Batu Reput (Dolomite) - SMR L matrix interaction compared with Batu Reput (Dolomite) filled ENR-50.

scholarly journals STRUCTURES AND PROPERTIES OF NATURAL RUBBER/ORGANOCLAY NANOCOMPOSITES

2011 ◽  
Vol 14 (1) ◽  
pp. 30-38
Author(s):  
Hien Quang Pham ◽  
Son Thanh Thanh Do ◽  
Nieu Huu Nguyen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Abrasion Resistance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structures And Properties ◽  
Scanning Electron

Natural rubber (NR), 30% epoxidized natural rubber (ENR30) and organoclays (Nanomer I28E and I30E) are blended in Brabender. Dispersions of the organoclay in NR are investigated by X – ray diffraction (XRD) and scanning electron microscopy (SEM). The results revealed the increase of dispersion efficiency by the addition of ENR30 as a compatibilizer. The existence of organoclay I28E reduces the vulcanization time, while torque value increases slightly and mechanical properties (abrasion resistance, modulus M100, modulus M300, tensile strength, tear strength) are improved considerably.

scholarly journals Analysis of PLA Composite Filaments Reinforced with Lignin and Polymerised-Lignin-Treated NFC

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2174
Author(s):  
Diana Gregor-Svetec ◽  
Mirjam Leskovšek ◽  
Blaž Leskovar ◽  
Urška Stanković Elesini ◽  
Urška Vrabič-Brodnjak
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Glassy State ◽  
Nanofibrillated Cellulose ◽  
Dynamic Mechanical Properties ◽  
Initial Modulus ◽  
Surface Modified ◽  
Scanning Electron

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.

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