Cure and Mechanical Properties of Natural Rubber Filled Bacterial Cellulose

2016 ◽  
Vol 705 ◽  
pp. 40-44
Author(s):  
Chaiwute Vudjung

Natural rubber (NR) containing the nata de coco fiber or Bacterial cellulose (BC) was prepared by co-coagulation of BC and concentrated NR latex with CaCl2 and compounded by two roll mill. The effect of BC content was the important factor in this study. It was that found tensile strength and elongation at break of NR filled BC (NR/BC) decreased with increasing BC content. The addition of BC into NR affect Mooney viscosity of NR/BC masterbatch, with increasing BC content, scorch time and cure time of their compound decreased.

2017 ◽  
Vol 744 ◽  
pp. 295-299
Author(s):  
Saowaluk Boonyod ◽  
Chaiwute Vudjung

Natural rubber (NR) containing the nata de coco fiber or Bacterial cellulose (BC) was prepared by co-coagulation of BC and concentrated NR latex with CaCl2 and compounded by two roll mill. The effect of oleic acid (OA) containing in NR filled BC (NR/BC) was the important factor in this study. BC was varied from 0–25 parts per hundred parts of rubber (phr), and the Mooney viscosity, cure characteristics and mechanical properties of NR/BC with and without OA as compatiblizer was evaluated. It was found that tear strength and elongation at break of NR/BC containing OA improved. The addition of OA into NR/BC affect vulcanization properties of NR/BC masterbatch that retard the cure time of their compound. Of all BC contents investigated, the vulcanized NR/BC at 10-20 phr of BC with OA shows the optimum tear strength and the morphology of the vulcanized NR/BC is improved by the addition of OA.


2005 ◽  
Vol 21 (3) ◽  
pp. 183-199
Author(s):  
G.K. Jana ◽  
C.K. Das

De-vulcanization of vulcanized elastomers represents a great challenge because of their three-dimensional network structure. Sulfur-cured gum natural rubbers containing three different sulfur/accelerator ratios were de-vulcanized by thio-acids. The process was carried out at 90 °C for 10 minutes in an open two-roll cracker-cum-mixing mill. Two concentrations of de-vulcanizing agent were tried in order to study the cleavage of the sulfidic bonds. The mechanical properties of the re-vulcanized rubber (like tensile strength, modulus, tear strength and elongation at break) were improved with increasing concentrations of de-vulcanizing agent, because the crosslink density increased. A decrease in scorch time and in optimum cure time and an increase in the state of cure were observed when vulcanized rubber was treated with high amounts of de-vulcanizing agent. The temperature of onset of degradation was also increased with increasing concentration of thio-acid. DMA analysis revealed that the storage modulus increased on re-vulcanization. From IR spectroscopy it was observed that oxidation of the main polymeric chains did not occur at the time of high temperature milling. Over 80% retention of the original mechanical properties (like tensile strength, modulus, tear strength and elongation at break) of the vulcanized natural rubber was achieved by this mechanochemical process.


2017 ◽  
Vol 735 ◽  
pp. 153-157
Author(s):  
Wasinee Pinpat ◽  
Wirunya Keawwattana ◽  
Siree Tangbunsuk

Silica has been used as reinforcing filler in natural rubber for a period of time as it results in excellent properties for NR vulcanizes. Rice husk ash (RHA), bagasse ash (BA), and oil palm ash (OPA) obtained from agricultural wastes are mainly composed of silica in the percentage of 80.00%, 57.33%, and 40.20% by weight, respectively. The effect of these fillers on cure characteristics and mechanical properties of natural rubber materials at fixed silica content at 35 parts per hundred of rubber (phr) were investigated. The results indicated that ashes showed greater cure time compared to that of the silica. The incorporation of ashes into natural rubber gradually improved compression set but significantly decreased tensile strength, elongation at break, and resilience. Moreover, young's modulus increased, while hardness showed no significant change with the addition of ashes. Overall results indicated that ashes could be used as cheaper fillers for natural rubber materials where improved mechanical properties were not critical.


2014 ◽  
Vol 931-932 ◽  
pp. 68-72
Author(s):  
Komsun Temna ◽  
Nitinart Saetung ◽  
Anuwat Saetung

In this work, the sponge rubbers based on cassava starch masterbatch in latex phase with the difference technique (non-gelatinized and gelatinized cassava starch) were preformed. The cassava starch contents from 0 to 70 phr were also studied. The cure characteristic, mechanical and morphological properties were investigated. It was found that the scorch time and cure time were increased with an increasing of cassava starch contents in both techniques. The mechanical properties i.e., tensile strength, elongation at break and tear strength were decreased with an increasing of cassava starch contents, except 500% modulus. However, the sponge based on gelatinized technique gave the better mechanical properties than that of non-gelatinized cassava starch. The SEM micrographs of sponge NR from gelatinized technique were also able to confirm a good interfacial interaction between hydrophilic cassava starch and hydrophobic NR.


2014 ◽  
Vol 979 ◽  
pp. 155-158 ◽  
Author(s):  
Apaipan Rattanapan ◽  
Jitrakha Paksamut ◽  
Pornsri Pakeyangkoon ◽  
Surakit Tuampoemsab

This work studied possibilities of using waste silicon carbide (SiC) particles from abrasive industry as alternative filler in natural rubber (NR) compounds. The rubber was prepared by using natural rubber grade STR 5L and waste silicon carbide loading of 0, 10, 20, 30 and 40 phr. Firstly, the rubber were compounded by using two roll mill and then using Oscillating Disc Rheometer for studying cure time at one hundred and fifty degree Celsius. Then, shear viscosity and extrudate swell of the compounded natural rubber were characterized by using capillary rheometer at 100°C. The result showed that the apparent shear viscosity increased slightly with increasing waste silicon carbide loading and the percentage of extrudate swell was found to be a decreasing function of the filler loading. Then, test tensile by using the prepared samples for studying tensile modulus, tensile strength and elongation at break. The result showed that tensile modulus and tensile strength increased with increasing waste silicon carbide. On the other hand, the elongation at break of the filled natural rubber decreased with increasing waste silicon carbide. Finally, bring the sample to test hardness by using shore A. Results indicated that waste silicon carbide direct variation with the indicator of hardness.


2017 ◽  
Vol 751 ◽  
pp. 332-336 ◽  
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan

This research aimed to investigate the possibility of pyrolytic carbon black (PCB) used as filler in natural rubber (NR) and its effect on Mooney viscosity, cure characteristics and mechanical properties compared with commercial carbon black (N774). The results revealed that Mooney viscosity, stiffness and heat build-up tended to increase with increasing both PCB and N774 loading, whereas elongation at break decreased. However, the maximum tensile and tear strengths appeared at the optimum filler loading for both PCB and N774. At similar filler content, PCB-filled NR compounds have higher cure time, heat build-up and thermal resistance. Nevertheless, they exhibited lower Mooney viscosity and mechanical properties compared to N774-filled NR. Finally, it can be concluded that PCB could be utilized as filler in NR compound to act as semi-reinforcing filler and was classified as a filler to reduce costs.


2010 ◽  
Vol 123-125 ◽  
pp. 1171-1174 ◽  
Author(s):  
Wittawat Wongsorat ◽  
Nitinat Suppakarn ◽  
Kasama Jarukumjorn

Sisal fiber/natural rubber (NR) composites were prepared by the incorporation of sisal fiber into NR at various content (10, 20, 30 phr) using a two-roll mill. Natural rubber grafted with maleic anhydride (NR-g-MA) prepared in house was used to improve interfacial adhesion between sisal fiber and NR matrix. NR-g-MA contents were varied. Mechanical properties, morphologies, and cure characteristics of the composites were studied. Maximum torque, modulus at 100% strain (M100), modulus at 300% strain (M300), and hardness of the composites increased with increasing fiber content while scorch time, cure time, tensile strength, and elongation at break decreased. The addition of NR-g-MA into the composites gave a positive impact on M100, M300, tensile strength, and hardness. Moreover, increasing NR-g-MA content resulted in increased scorch time, cure time, maximum torque, M100, M300, tensile strength, and hardness of the composites. SEM micrographs of the composites revealed that the addition of NR-g-MA into the composites improved the interfacial interaction between sisal fiber and NR matrix. In addition, the compatibilized NR composites exhibited higher specific tensile strength and modulus than the carbon black/NR composites.


2010 ◽  
Vol 123-125 ◽  
pp. 55-58 ◽  
Author(s):  
Chalermpan Keawkumay ◽  
Kasama Jarukumjorn ◽  
Nitinat Suppakarn

Montmorillonite (MMT) was modified by octadecylamine (ODA) surfactant. The surfactant contents were varied, i.e. 0.5, 1.0 and 2.0 times the cation exchange capacity (CEC) of the MMT. XRD and FTIR spectra of the organoclay revealed that ODA molecules intercalated into MMT layers. The MMT-ODA was melt-mixed with natural rubber (NR) using a two roll mill. Effects of surfactant content and organoclay content on cure characteristics, mechanical properties, and morphologies of NR nanocomposites were investigated. Morphologies of the NR nanocomposites, with increasing surfactant content, revealed the exfoliated structure and the good dispersion of the organoclay in the NR matrix. These caused the enhancement of mechanical properties of the NR nanocomposites. With increasing the MMT-ODA2 content up to 5 phr, scorch time and cure time of the NR nanocomposites decreased while their tensile strength increased.


2014 ◽  
Vol 1033-1034 ◽  
pp. 912-915
Author(s):  
Guang Lu ◽  
Hong Hai Huang ◽  
He Ping Yu ◽  
Yong Zhou Wang

In an attempt to improve the properties of natural rubber-based medical products, natural rubber (NR) was blended with chitosan (CS) and poly(3-hydroxybutyrate) (PHB) in an laboratory type internal mixer, with the total amount of CS and PHB is of 1, 3, 5, 10, 15 and 20 parts per hundred rubber (phr) , and CS and PHB is of a ratio of 1:1. The testing for processing properties of NR/CS/PHB compounds showed that the Mooney viscosity of NR/CS/PHB compounds increased with the addition of 1.0 phr CS/PHB and then decreased with increase in CS/PHB content, but the Mooney viscosity of each NR/CS/PHB compound was higher than that of NR compound; the minimum torque (ML) increased only slightly, while the maximum torque (MH) increased gradually, with increase in NR/CS/PHB content; thescorching tendency of NR/CS/PHB compounds increased with the increase in CS/PHB content; the optimum cure time (t90) decreased firstly, then increased with increase in CS/PHB content, and was not greatly different from that of NR compound. The results of mechanical properties of NR/CS/PHB vulcanizates showed that the tensile strength and elongation at break deceased, whereas the 300% and 500% moduli, tear strength and hardness increased, with increase in CS/PHB content.


2011 ◽  
Vol 410 ◽  
pp. 63-66 ◽  
Author(s):  
Wittawat Wongsorat ◽  
Nitinat Suppakarn ◽  
Kasama Jarukumjorn

Sisal fiber/natural rubber (NR) composites were prepared by the incorporation of sisal fiber into NR at contents of 10-30 phr. Fiber treatment (alkalization) and adding maleic anhydride grafted natural rubber (NR-g-MA) were used to improve interfacial adhesion between sisal fiber and NR matrix. Mechanical properties, morphologies, and cure characteristics of the composites were studied. With increasing fiber content, modulus at 100% strain (M100), modulus at 300% strain (M300), and hardness of the composites increased whereas tensile strength and elongation at break decreased. Cure time of the composites decreased with increasing fiber content but scorch time was not much affected by fiber content. Alkali treated sisal fiber/NR composite exhibited higher tensile properties and hardness than untreated sisal fiber/NR composite at all fiber content due to the improved adhesion between fiber and NR matrix through the mechanical interlocking mechanism. Alkalization showed no effect on scorch time and cure time of the composites. The addition of NR-g-MA into the composites increased M100, M300, tensile strength, and hardness but prolonged scorch time and cure time. NR-g-MA provided more effective improvement of the mechanical properties of the composites when compared to fiber alkalization.


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