Polybutadiene nanocomposites

In advanced approach, the CNT is incorporated to a 50 50 blend of styrene-butadiene rubber and butadiene rubber solution (Das et al. 2008 Mari and Schaller 2009 Yu et al. 2011). The predispersed CNTs in ethanol is formed and after that the CNT-alcohol suspension is mixed with the polybutadiene at elevated temperature. CNTs-fifled polybutadiene nanocomposites prepared by a technique which show meaiungfully improved physical behavior already at very low concentrations of the CNTs (Mari and Schaller 2009). The particular high ratio of the CNTs enabled the formation of a conductive percolating network in the composites at concentrations lower than 2 wt%. By the presence of CNTs, as opposed to the electrical conduction properties, the thermal conductivity of the composites not... 

Table 12.2 summarizes the mechanical properties of polybutadiene rubber-clay nanocomposites. The hardness, tensile strength, elongation at break, and permanent set all improved with increasing the clay content (5—40 phr)." " The mechanical properties of polybutadiene rubber-clay nanocomposite with 20 pin-clay content have been compared to those of the polybutadiene composites filled with 20 phr carbon black (SFR and N330), as presented in Table 12.3. This data shows that the organically-modified layered silicate was as effective a reinforcing filler, as carbon black. Some of the mechanical properties of polybutadiene nanocomposite such as hardness, tear strength, and tensile strength even exceeded those of the carbon black filled compounds." " These excellent mechanical properties of the nanocomposites resulted from the uniformly dispersed layered silicate in the elastomer matrix, and the strong interaction between the nanoclay layers and rubber chains. Thus layered silicates could be used in the polybutadiene industry as a promising reinforcing filler, if the layers...

Poly(styrene-fc-butadiene) copolymer-clay nanocomposites were prepared from dioctadecyldimethyl ammonium-exchanged MMT via direct melt intercalation [91]. While the identical mixing of copolymer with pristine montmorillonite showed no intercalation, the organoclay expanded from 41 to 46 A, indicating a monolayer intercalation. The nanocomposites showed an increase in storage modulus with increasing loading. In addition, the Tg for the polystyrene block domain increased with clay content, whereas the polybutadiene block Tg remained nearly constant. 

It should be noted that, unlike Ag nanocrystals of Ag-PPX nanocomposites with 2max of plasmon band in the range 430-445 nm, nanocrystals prepared by reduction of Ag+ ions in solution of poly (N-vinylpyrrolidone) [81] as well as nanocrystals formed by introducing Ag vapors into liquid polybutadiene [77] have plasmon band with 2max around 410 nm. As is specified in Ref. [81], the UV-vis spectrum of nanocrystals depends on their size and form as well as on the surrounding matrix. The plasmon band of Ag nanocrystals [77, 81] coincides with that of modeling spherical nanoparticles with a smooth ideal surface, which were theoretically treated from different points of view in Ref. [82, 83]. 

Recently, nanocomposites were prepared with different grades of nitrile rubber with acrylonitrile contents of 19%, 34%i, and 50%i, with SBR (23%i styrene content), and with polybutadiene rubber with Na-montmorillonite clay. The clay was modified with... 

Sadhu, S. Bhowmick, A.K. Preparation and properties of nanocomposites based on acrylonitrile-butadiene rubber, styrene-butadiene rubber, and polybutadiene rubber. J. Polym. Sci. B Polym. Phys. 2004, 42 (9), 1573-1585. 

Ganter et al. [62], utUized a synthetic layered fluorohec-torite silicate and organomontmorillonite to evaluate the role of functional rubber exchanged onto the synthetic clay in the preparation of styrene-butadiene rubber nanocomposites. The functional rubber that was exchanged onto the fluorohectorite was amino-terminated polybutadiene. The styrene-butadiene was dispersed in solvent and then dis-... 

The thermal stability of calcium carbonate (CaC03) nanoparticles on polybutadiene rubber (PBR) were studied by Shimpi and Mishra [105]. They observed that the incorporation of nano CaCOs in PBR shows better thermal stability. At 12 wt% of nano CaCOs (21, 15, and 9 nm) filled in PBR shows decomposition temperature at 491, 483, and 472 °C, respectively. At 4 wt% loading of filler, decomposition temperature is observed to be 488,480,450 °C for nano CaCOs (21, 15, and 9 nm), respectively. This enhancement in thermal stability is due to uniform dispersion of nano CaCOs throughout the matrix that keeps the rubber chains intact on cross-linking, which prevent out diffusion of the volatile decomposition product [106]. The presence of nanoinorganic particles in between the mbber chains is responsible for preventing the diffusion of the volatile decomposition products firom the mbber nanocomposites at same time. It is clear that nanoinorganic filler provides better thermal stability as compared with commercial micron size filler. 

On the other hand, the development of polybutadiene/day nanocomposites prepared by in-situ metal-catalyzed polymerization is still in its embryonic stage. 

High impact polystyrene (HIPS) is a blend of PS that has been polymerized in the presence of polybutadiene. This leads to PS chains with grafted polybutadiene, as well as some free PS and PB, and the resultant polymer blend has improved impact strength. HIPS/MMT nanocomposites were formed though in-situ bulk polymerization in the presence of polybutadiene [86]. Intercalated nanocomposites with improved thermal stabihty were formed although the dispersion was different in the PS matrix phase compared to the rubber phase. 

Natural rubber/cw-1,4-polybutadiene (NR/BR) blends (70/30 mass ratio) have been widely used in the tire industry. Many nanocomposites based on organo-montmorillonite (OMMT)/rubber blends have been investigated. However, relatively little attention had been paid to binary rubber hybrids/ montmorillonite nanocomposites, and according to Zheng Gu et ah, no studies existed dealing with OMMT/NR/BR nanocomposites. So, the authors described the preparation of OMMT/NR/BR nanocomposites by direct mechanical blending and determined the cure characteristics, static mechanical properties, dynamic mechanical properties, and thermal stability of the nanocomposites. OMMT/NR/BR nanocomposites had exactly the same onset decomposition temperature and lower thermal degradation rate as the NR/BR blends. 

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