Thermoplastic Natural Rubber Based on Blending of Co-Polyester: Effect of Amount of Epoxide Groups in Epoxidized Natural Rubber on Preperties

2012 ◽  
Vol 626 ◽  
pp. 50-53 ◽  
Author(s):  
Krisna Sasdipan ◽  
Azizon Kaesaman ◽  
Charoen Nakason

TPNRs based on blending of co-polyester (i.e., PBT/PC) and epoxidized natural rubber (ENR) with various epoxide content (i.e., 10, 20, 30, 40 and 50 mol% epoxide) were prepared by dynamic vulcanization. It was found that the co-polyester/ENR blends gave better properties (i.e., mechanical, dynamic mechanical, morphological and oil resistant properties) than that of co-polyester/unmodified NR blend. It was also found that co-polyester/ENR with 50 mol% epoxide exhibited the highest tensile strength, elongation at break, modulus at 100% elongation, hardness, storage modulus, complex viscosity and oil resistant properties but showed the lowest tension set value. This indicates the highest elasticity. Moreover, it was found that size of vulcanized rubber domains dispersed in thermoplastic matrix decreased with increasing the epoxide content in ENR molecules.

2013 ◽  
Vol 844 ◽  
pp. 81-84 ◽  
Author(s):  
Rawviyanee Romin ◽  
Charoen Nakason ◽  
Anoma Thitithammawong

Thermoplastic elastomers (TPEs) based on dynamically cured epoxidized natural rubber/copolyamide (ENR/COPA) blends were prepared. Influence of curing systems (i.e., sulphur, peroxide, mixed sulphur and peroxide and phenolic resin cured systems on mechanical, dynamic and morphological properties of the blends were investigated. It was found that the blend with phenolic cured system exhibited superior mechanical and set properties. That is higher tendency to recover to its original shape after a prolong extension. It was also found that the blend with peroxide cured system exhibited higher storage modulus and complex viscosity than those of the blends with mixed sulphur and peroxide, phenolic and sulphur cured system, respectively. Furthermore, the TPVs blend with peroxide cured system showed the smallest vulcanized rubber particles.


2013 ◽  
Vol 844 ◽  
pp. 140-143
Author(s):  
Wiphawadee Pongdong ◽  
Charoen Nakason ◽  
Claudia Kummerlöwe ◽  
Norbert Vennemann

Thermoplastic vulcanizates (TPVs) based on thermoplastic polyurethane (TPU) and epoxidized natural rubber (ENR) were prepared by dynamic vulcanization. In this study, the influence of different types and loading levels of filler on the properties of ENR-25/TPU blends was investigated. Furthermore, a filler from renewable resources, namely Rice Husk Ash (RHA), and conventional silica were incorporated in the blends (i.e., premixed with ENR-25). Then, various loading levels of filler were investigated at 10, 20 and 30 phr and compared with the unfilled blend. It was found that the incorporation of filler into the blend shows higher complex viscosity, mechanical properties in terms of Youngs modulus, tensile strength and hardness compared with the TPV without filler. The incorporation of ENR-25 into the blend shows lower hardness than pure TPU. It was also found that TPV filled with RHA revealed almost identical values for Youngs modulus, tensile strength, elongation at break and hardness, than the same TPV filled with conventional silica. This indicates rice husk ash has great potential to be used as filler in polymer composites based on ENR/TPU blends.


2012 ◽  
Vol 626 ◽  
pp. 58-61 ◽  
Author(s):  
Rawviyanee Romin ◽  
Charoen Nakason ◽  
Anoma Thitithammawong

Thermoplastic elastomers based on blending of epoxidized natural rubber with 30 mol% epoxide (ENR-30) with polyamide-12 (PA-12) (i.e., ENR-30/PA-12) and blending of ENR-30 with co-polyamide-12 (ENR-30/CO-PA-12) were prepared by dynamic vulcanization technique. It was found that the dynamically cured ENR-30/PA-12 blends exhibited higher tensile strength, Youngs modulus and hardness than those of the ENR-30/CO-PA-12 blends. However, the elongation at break of the ENR-30/PA-12 blend was very poor and hence the tension set could not be determined. On the other hand, the ENR-30 contents in the dynamically cured ENR-30/CO-PA-12 influence on various properties. These include lowering of stiffness and tensile properties together with enhancing elastic properties (i.e. lower tension set and tan ) of the blends.


2013 ◽  
Vol 844 ◽  
pp. 89-92
Author(s):  
Boripat Sripornsawat ◽  
Azizon Kaesaman ◽  
Charoen Nakason

Maleated natural rubber (MNR) was synthesized and formulated to prepare thermoplastic natural rubber (TPNR) by blending with co-polyamide (COPA). It was found that 100% modulus, tensile strength, elongation at break, hardness and degree of swelling increased with increasing proportion of COPA. However, degree of swelling and tension set value decreased which reflects enhancing of rubber elasticity. Dynamic properties were also determined by a rotor less oscillating shear rheometer (Rheo Tech MDpt). It was found that increasing proportion of MNR caused increasing of storage modulus and complex viscosity but decreasing tan δ value. Morphological properties were also determined by SEM technique. It was found that the MNR/COPA simple blends with the proportion of rubber 40, 50 and 60 wt% exhibited the co-continuous phase structures.


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.


2019 ◽  
Vol 36 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Ajaman Adair ◽  
Azizon Kaesaman ◽  
Pairote Klinpituksa

Epoxidized natural rubber (ENR) and a superabsorbent polymer composite (SAPC) along with other minor components were mechanically blended in an internal mixer (Brabender Plasticorder) at 40°C and 60 r/min rotor speed with 80% fill factor. The SAPC was synthesized by grafting polyacrylamide onto hydroxyethyl cellulose backbones and adding bentonite clay. The first water-swelling behavior was investigated with alternative epoxidation levels of the ENR. Water-swellable rubber (WSR) performed well in terms of water absorbency, and weight loss was achieved with 50 mole% epoxidation level, so this ENR was chosen for the rubber matrix from which WSR was prepared with various contents of SAPC (0, 5, 10, 15, and 20 phr). The results indicated that SAPC loading positively affected water absorbency, which was resulted by increasing weight loss and loss of mechanical properties, such as tensile strength and elongation at break. However, the modulus increased with SAPC content. WSR formulated from ENR-50, SAPC, and other ingredients resulting in good water-swelling behaviors and modulus, while the tensile strength and elongation at break had opposition. SAPC was an important factor to control the overall WSR properties.


2012 ◽  
Vol 602-604 ◽  
pp. 690-695
Author(s):  
Hua Dong Wang ◽  
Rui Wang ◽  
Mao Fang Huang ◽  
Qi Yang

Thermoplastic vulcanizates (TPVs) based on epoxidized natural rubber (ENR) and polypropylene (PP) were prepared in an internal mixer at 180°C. The effects of curing systems (i.e., sulfur and peroxide) on morphological, rheological, thermal and mechanical properties were studied. It is found that the sulfur cured TPVs show higher tensile strength, tear strength and elongation at break than those cured with the DCP systems. The rheological analysis indicates that TPVs cured with DCP system show lower apparent shear viscosity than those with sulfur system. SEM studies show that TPVs vulcanized with DCP system exhibit smaller and finely dispersed rubber domains, which provides it higher thermal stability than sulfur cured TPVs.


2005 ◽  
Vol 21 (1) ◽  
pp. 39-53 ◽  
Author(s):  
H. Ismail Halimatuddahliana ◽  
H. Md. Akil

The effects of trans-polyoctene rubber (TOR) and dynamic vulcanization on the processability, tensile properties, oil resistance and morphology of unvulcanized and vulcanized polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/ natural rubber (NR) blends were investigated. The highest stabilization torque was obtained with vulcanized PP/EPDM/NR blends containing TOR, followed by control blends and unvulcanized blends containing TOR. At a similar blend ratio the tensile strength and the stress at 100% elongation of vulcanized PP/ EPDM/NR blends containing TOR were again higher than those of unvulcanized blends containing TOR and of the control blends. However, the opposite trend was observed with respect to elongation at break, whereby vulcanized PP/EPDM/NR blend had the lowest values The oil resistance of unvulcanized and vulcanized blends containing TOR was greater than that of the control blends. From morphological studies, it is clear that the incorporation of TOR in unvulcanized and vulcanized PP/EPDM/NR blends improved the homogeneity and promoted good adhesion between phases.


2014 ◽  
Vol 660 ◽  
pp. 306-311
Author(s):  
A.A. Afiratul ◽  
N.Z. Noimam ◽  
C.M. Ruzaidi ◽  
Sung Ting Sam ◽  
M.F. Omar ◽  
...  

The effects on the properties of recycled latex glove (RL-G) filled Epoxidized Natural Rubber (ENR 50) were studied. Both compounds were prepared by two roll mill at five different compositions of RL-G (5, 15, 25, 35 and 50 phr). The size range of RL-G particles i.e., S1 (300μm-700μm) and S2 (3cm-5cm) were used. The properties such as tensile properties (tensile strength, elongation at break, and stress at 100% elongation) and morphology studies were determined. The results indicated that the both size, S1 and S2 of recycled latex glove filled ENR 50 blends exhibited an increased in tensile strength and elongation at break for increasing weight ratio of RL-G. Scanning electron microscopy (SEM) of the fracture surfaces shows that the fine size, S1 RL-G/ENR50 exhibited high surface roughness and matrix tearing lines than the coarse size, S2 thus improving the compatibility of RL-G/ENR50 compounds. The results overall indicated that the fine size, S1of RL-G filled ENR50 contributed to the better properties such as tensile strength and surface morphology compared to the coarse size, S2 mainly at 15 phr of RL-G content.


2013 ◽  
Vol 747 ◽  
pp. 375-378 ◽  
Author(s):  
Chaiwat Ruksakulpiwat ◽  
Wasaphon Wanasut ◽  
Apikiat Singkum ◽  
Ruksakulpiwat Yupaporn

This research shows a great potential of cogon grass fiber to be used as a reinforcement in epoxidized natural rubber composites. The thermal and mechanical properties of cogon grass fiber-epoxidized natural rubber composites were studied. The chemical treatment of cogon grass fiber to be used as a reinforcing filler was revealed. Effects of fiber treatment method and treatment time of cogon grass fiber on thermal properties of the fibers and their composites were elucidated. The addition of cogon grass fiber into epoxidized natural rubber (ENR) improved the mechanical properties of the composites.The result indicated that alkaline treatment followed by acid treatment of cogon grass fiber led to an increase in thermal decomposition temperature and mechanical properties of the composites more than that without acid treatment. With increasing the amount of fiber, tensile strength of ENR composites were significantly increased while elongation at break was insignificantly changed. ENR with the addition of 4-Amino-6-hydroxy-2-mercaptopyrimidine monohydrate as coupling agent (ENRC) was shown to have higher tensile strength, modulus at 200% elongation and elongation at break than ENR. Improved mechanical properties were also obtained in ENRC composites compared to those of ENR composites.


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