Curing characteristics and mechanical and aging properties of ethylene propylene diene monomer/calcium carbonate/bentonite hybrid composites

2016 ◽  
Vol 49 (5) ◽  
pp. 397-407 ◽  
Author(s):  
Nurus Sakinah Che Mat ◽  
Hanafi Ismail ◽  
Nadras Othman

Ethylene propylene diene monomer (EPDM)/calcium carbonate/bentonite (Bt) hybrid composites were prepared via a laboratory size two-roll mill. In this work, loading ratio of calcium carbonate to Bt was varied, that is, 30/0, 5/25, 15/15, 25/5 and 0/30 parts per hundred rubber. The effect of partial replacement of calcium carbonate with Bt on the curing characteristics, tear properties, morphology, aging and fatigue life of the hybrid composites was studied. On increasing Bt loading, cure time, scorch time and maximum torque of EPDM/calcium carbonate (CaCO3)/Bt composites decreased, whereas minimum torque increased. The tear strength and fatigue life of EPDM/CaCO3/Bt hybrid composites showed improvement with increasing Bt loading. The results also showed that the retention of aging of EPDM/CaCO3/Bt hybrid composites decreased with increasing Bt loading.

2015 ◽  
Vol 754-755 ◽  
pp. 120-124
Author(s):  
Z. Norhafizah ◽  
N.Z. Noriman ◽  
S.T. Sam ◽  
Hanafi Ismail ◽  
Mohd Firdaus Omar

Most of the polymeric materials blending together with recycled waste rubber powder attributed to the economical and processing advantages for product specification. Therefore, the effect of curing characteristics, hardness and crosslink density of ethylene propylene diene monomer/recycled acrylonitrile butadiene rubber (EPDM/NBRr) blends were studied. The EPDM/NBRr blends were prepared at four different compositions (95/5, 85/15, 75/25 and 65/35) with two different sizes (S1: 250-500μm and S2: 3-10cm) of NBRr. Results indicated that the scorch time t2, cure time t90, and maximum torque (MH) for both EPDM/NBRr (S1) and EPDM/NBRr (S2) decreased, but the minimum torque (ML) increased.The increase of NBRr content in EPDM/NBRr leads to the increase in hardness and consequently decreases the crosslinking density of the blends. The incorporation of 15phr of S1 recycled NBRr appeared to better overall properties.


2011 ◽  
Vol 471-472 ◽  
pp. 957-962 ◽  
Author(s):  
Siti Zuliana Salleh ◽  
Hanafi Ismail ◽  
Zulkifli Ahmad

In this research, natural rubber (NR) with halloysite nanotubes(HNTs)/carbon black (CB) hybrid filler at various filler loading was investigated where the total filler loading used in each compound were 40 phr. The curing characteristics, fatigue life and morphological properties of HNTs/CB/NR nanocomposites were studied. Laboratory two-roll mill was used for mixing process. The results revealed that vulcanizates containing more HNTs in hybrid filler exhibit longer scorch time (ts2) and cure time (t90) for curing characteristics and higher in fatigue life compared to vulcanizates with 40 phr of CB. The images from scanning electron microscope (SEM) confirmed that replacement of carbon black with halloysite nanotubes improved the fatigue life by showing more tearing surface on vulcanizates.


2018 ◽  
Vol 382 ◽  
pp. 94-98 ◽  
Author(s):  
Sarawut Prasertsri ◽  
Chaiwute Vudjung ◽  
Wunchai Inthisaeng ◽  
Sansanee Srichan ◽  
Kanchana Sapprasert ◽  
...  

The present research aimed to develop natural rubber (NR) hybrid composites reinforced with calcium carbonate/carbon black (CC/CB) and calcium carbonate/silica (CC/SC). The influence of CC/CB and CC/SC with various filler ratios (120/0, 90/5, 60/10, 30/15 and 0/20) on cure characteristics and mechanical properties of the vulcanizates was investigated and their reinforcing efficiency was compared. It has been found that incorporation of CB in the hybrid filler decreases the scorch time and cure time but increases crosslink density, whereas the incorporation of silica showed cure retardation. As CB or SC content increases, stiffness, tensile strength and tear strength increase, while elongation at break and compression set decrease. Scanning electron microscopy studies also reveal poor filler dispersion and poor adhesion between filler particles and matrix in the vulcanizates with increasing in CC content in a weight filler ratio which causes inferior mechanical properties. Incorporation of CB or SC content enhanced the mechanical properties of the vulcanizates, where CC/CB hybrid system exhibited higher reinforcing efficiency compared with CC/SC hybrid system.


2011 ◽  
Vol 471-472 ◽  
pp. 845-850 ◽  
Author(s):  
Komethi Muniandy ◽  
Hanafi Ismail ◽  
Nadras Othman

Rattan for its potential as a new type of filler was investigated in natural rubber (NR) compounds. Natural rubber (NR) compounds were prepared by the incorporation of rattan at different loadings into a natural rubber matrix with a laboratory size two roll mill. The effect of rattan loading as filler on curing characteristics, tensile properties, morphological properties using scanning electron microscopy (SEM) and rubber–filler interaction of rattan filled natural rubber compound were studied in the filler loading range of 0 to 30 phr. The results indicate that the scorch time (ts2) and cure time (t90) shorten with increasing filler loading, whereas the maximum torque (MH) showed an increasing trend. As the filler loading increases, the tensile strength and elongation at break decreases whilst tensile modulus; stress at 100 % elongation and stress at 300 % elongation increased. The rubber filler interactions of the rubber compound decreased with increasing filler loading. SEM studies indicate that the increasing rattan loading weakens the rubber-rattan interactions.


2011 ◽  
Vol 264-265 ◽  
pp. 646-651 ◽  
Author(s):  
Wittawat Wongsorat ◽  
Nitinat Suppakarn ◽  
Kasama Jarukumjorn

Natural rubber (NR) was reinforced with three types of filler: carbon black, calcium carbonate, and sisal fiber. NR composites were prepared on a two-roll mill. Filler content was 20 phr. Mechanical properties and cure characteristics of NR composites were studied. All NR composites had higher maximum torque than NR. NR filled with carbon black showed the highest maximum torque. However, scorch time and cure time of the NR composites were not much affected by filler types. In addition, influence of fiber treatment (alkalization) on mechanical properties and cure characteristics of sisal fiber-NR composites was investigated. Alkali treated sisal fiber-NR composite exhibited higher tensile properties and hardness than untreated sisal fiber- NR composite due to improved adhesion between the fiber and NR matrix. Moreover, alkali treated sisal fiber-NR composite had superior specific modulus and strength than NR composites filled with carbon black and calcium carbonate.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1116
Author(s):  
Dávid Zoltán Pirityi ◽  
Kornél Pölöskei

Rubber waste remains a challenge for material science because its covalently cross-linked structure hinders the establishment of the circular economy of rubber. Devulcanisation may provide a solution, as it converts rubber vulcanisates back into their original, uncured state. Devulcanised rubber may be revulcanised or incorporated into virgin rubber, thus waste is utilized and the use of primary resources is reduced at the same time. In this paper, we treated sulphur-cured EPDM (ethylene propylene diene monomer) rubber on a two-roll mill at various temperatures and frictions. We determined the effectiveness of devulcanisation via Horikx’s analysis, which suggested that low devulcanisation temperatures would result in a 50% decrease in cross-link density with minimal polymer degradation. The devulcanisate was recycled via two methods: (a) revulcanisation with extra curing agents, and (b) mixing it with various amounts of the original rubber mixture, preparing rubber samples with 25, 50, 75, and 100 wt% recycled content. Tensile tests revealed that the samples’ elastic properties were severely compromised at 75 and 100 wt% devulcanisate contents. However, tensile strength decreased only by 15% and 20% for revulcanisates containing 25% and 50% recycled rubber, respectively.


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