scholarly journals Dynamic Mechanical Properties of Vietnam Modified Natural Rubber via Grafting with Styrene

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
T. A. Dung ◽  
N. T. Nhan ◽  
N. T. Thuong ◽  
D. Q. Viet ◽  
N. H. Tung ◽  
...  

The dynamic mechanical behavior of modified deproteinized natural rubber (DPNR) prepared by graft copolymerization with various styrene contents was investigated at a wide range of temperatures. Graft copolymerization of styrene onto DPNR was performed in latex stage using tert-butyl hydroperoxide (TBHPO) and tetraethylene pentamine (TEPA) as redox initiator. The mechanical properties were measured by tensile test and the viscoelastic properties of the resulting graft copolymers at wide range of temperature and frequency were investigated. It was found that the tensile strength depends on the grafted polystyrene; meanwhile the dynamic mechanical properties of the modification of DPNR meaningfully improved with the increasing of both homopolystyrene and grafted polystyrene compared to DPNR. The dynamic mechanical properties of graft copolymer over a large time scale were studied by constructing the master curves. The value of bT has been used to prove the energetic and entropic elasticity of the graft copolymer.

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Thi Nhan Nguyen ◽  
Hieu Nguyen Duy ◽  
Dung Tran Anh ◽  
Thuong Nghiem Thi ◽  
Thu Ha Nguyen ◽  
...  

In this study, we investigated the improvement of the thermal and mechanical properties of Vietnam deproteinized natural rubber (DPNR) via graft copolymerization of methyl methacrylate (MMA). The graft copolymerization was achieved successfully in latex stage using tert-butyl hydroperoxide (TBHPO) and tetra-ethylenepentamine (TEPA) as radical initiators at 30°C. By grafting with various MMA feeds and initiator concentration of 6.6×10−5 mol/g-rubber, the highest grafting efficiency and conversion were achieved at MMA of 15 wt.% per kg of rubber, 68% and 90%, respectively. The structure of grafted copolymers was characterized by 1H NMR, FTIR-ATR, and GPC, and thermal properties were investigated through DSC and TGA measurements. These showed that graft copolymers were more stable and rigid than DPNR. Storage modulus (G′) of graft copolymer was found to double that of DPNR, which contributed to the formation of graft copolymer. After sulfur vulcanization, the mechanical properties of DPNR-graft-PMMA, such as tensile strength, tear strength, and hardness, were improved significantly. Curing behaviors of the graft copolymers were found to be remarkably better than virgin DPNR.


2002 ◽  
Vol 10 (5) ◽  
pp. 381-390 ◽  
Author(s):  
Viviane Xavier Moreira ◽  
Bluma Guenther Soares

Rubber blends containing nitrile rubber (NBR) and ground ethylene-vinyl acetate copolymer waste (EVAW) from the footwear industry have been prepared over a wide range of composition (up to 90 phr of waste component). The ground EVAW had particle size in the range of 100-350 mm and a gel content of 60±5%. The effect of different amounts of EVA waste on the tensile strength, elongation at break, hardness, tear strength and dynamic mechanical properties was studied. EVAW had a good reinforcing effect on the NBR matrix. A combination of optimum tensile properties, resistance to solvent penetration and dynamic mechanical properties, such as storage modulus and loss tangent was achieved by introducing 50 phr of EVAW in the NBR matrix. This composition also presents a more uniform morphology, as indicated by scanning electron microscopy.


2014 ◽  
Vol 925 ◽  
pp. 308-312 ◽  
Author(s):  
Mou'ad A. Tarawneh ◽  
Sahrim Haji Ahmad ◽  
Yu Li Jiun ◽  
Radwan Dweiri ◽  
Ibrahim N. Hassan

In this paper the polymer nanocomposite of nickel zinc (NiZn) ferrite nanoparticles incorporated into the thermoplastic natural rubber nanocomposite (TPNR) were prepared via melt blending method. The effect of different NiZn loading (2-10 wt%) on morphology, tensile and dynamic mechanical properties of the obtained composites was investigated. It was found that NiZn ferrite is well dispersed in the thermoplastic natural rubber matrix. The tensile results indicated that filler loading has improved the tensile strength and Youngs modulus of the nanocomposite. However, the elongation at break decreased with increasing the percentage of NiZn. Dynamic mechanical test showed that the highest storage modulus is at 8 wt% filler. Any further increment of the filler content leads to the formation of agglomerate hence affecting the properties. The Scanning electron micrograph (SEM) micrographs reveal aspect ratio and filler orientation in the TPNR matrix also strongly promoted interfacial adhesion between the filler and the matrix to control its properties.


2013 ◽  
Vol 844 ◽  
pp. 365-368 ◽  
Author(s):  
Kontapond Prukkaewkanjana ◽  
Seiichi Kawahara ◽  
Jitladda Sakdapipanich

Natural rubber (NR) is one of the most important agriculture products of Thailand, which is an important material with unique and special characteristics used in wide range of applications such as mechanical properties, excellent strength, and elasticity. However, it is inferior in oil resistance due to the presence of hydrogen and carbon in its structure. This inherent drawback of NR has limited its application in industry. In order to expand the use of NR, this research is interested to improve the oil resistance of NR without loss of outstanding properties by grafting NR with acrylonitrile (AN) monomer to form the nano-matrix structure. The influences of the initial monomer concentration and initial initiator concentration were investigated. These effects on structure, mechanical properties and oil resistance properties were studied by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy, tensile machine, and swelling in toluene, respectively. It was found that the tensile strength and oil resistance properties of graft copolymerization of AN onto NR increased with increasing the percentage grafting efficiency of acrylonitrile monomer.


2013 ◽  
Vol 844 ◽  
pp. 109-112 ◽  
Author(s):  
Chesidi Hayichelaeh ◽  
Charoen Nakason ◽  
Anoma Thitithammawong

Epoxidized natural rubber (ENR)/Polypropylene (PP) thermoplastic vulcanizates were prepared by melt mixing method in an internal mixer. Influences of different mixing methods for incorporation of processing oil into the TPVs on tensile and dynamic mechanical properties of the TPVs and crystallinity of the PP were investigated. Results show that distribution of processing oil in the ENR/PP TPV is important due to the processing oil can promote and in the same time can interrupt an improvement in elastomeric properties of the TPV. Incorporation of processing oil into the ENR phase by preparation of oil extended ENR (the mixing method 1) before mixing with the PP was the better way to produce the TPV. It promoted the TPV with superior tensile and dynamic mechanical properties than the TPVs prepared from the mixing method 2 and 3 in which the processing oil was directly added into the PP phase. Furthermore, the TPV from the mixing method 1 had less effect of processing oil on the PP crystallization.


2013 ◽  
Vol 712-715 ◽  
pp. 111-114 ◽  
Author(s):  
Tian Ming Gao ◽  
Mao Fang Huang ◽  
Rui Hong Xie ◽  
Hong Lian Chen

Surface modified nanocrystalline cellulose (NCC) was prepared by silicon-69, and then blended into natural rubber latex to prepare nanocomposites. The nanocomposites properties of tensile properties, tear strength, morphology and thermal dynamic mechanical properties were measured by mechanical property testing, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA), respectively. The results showed that modified NCC is homogeneously distributed throughout NR matrix, which leads to the enhancement on mechanical properties. Moreover, the storage modulus (E) of modified nanocellulose filled NR is higher than unmodified nanocellulose filled NR, and the tanδ is reversed.


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