Biorenewable polyisoprene latex obtained from natural rubber, Hevea brasiliensis, was used to prepare the reusable polyisoprene-poly(alkyl acrylate) foam for petroleum-based liquid absorption. The foam was produced via latex vulcanization and cured by steaming. The effect of various types of poly(alkyl acrylate) such as poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA), and poly(butyl acrylate) (PBA) on oil sorption capacity of the foam were studied. Scanning electron microscope (SEM) images showed interconnected open-cell macrostructure with the foam porosity greater than 75% and good compression set. The oil sorption capacity of the foam was in the range of 2.0-16.6 g g 21 . The addition of poly(alkyl acrylate) enhanced hydrophobicity and oil sorption capacity of the foam. The absorbed oil was easily recovered by squeezing and the foam can be reused up to 30 sorption-desorption cycles and still preserve high quality sorption.

NR foam was modified via graft copolymerization with oleophilic monomer such as methyl methacrylate (MMA) or butyl methacrylate (BMA). Polymethyl methacrylate (PMMA) and polybutyl methacrylate (PBMA) were prepared by emulsion polymerization. The average particle size of PMMA and PBMA emulsion were 58.7±5.3 nm and 57.6±0.8 nm, respectively. The effect of PMMA or PBMA emulsion loading onto NR foam was studied over the range 0.05 2.0 phr. The functionality of modified NR foam was characterized by Fourier Transform Infrared Spectroscopy (FTIR). Thermal properties of modified NR foam were confirmed by thermogravimetric analysis (TGA). The results showed two step degradations which were attributed to natural rubber and PMMA or PBMA contents. The modified NR foam could quickly absorb gasoline and organic solvent such as toluene and xylene, which found in petroleum product. The maximum oil absorbency (gram of absorbency per gram of foam) of gasoline, diesel, engine oil, toluene and xylene were achieved at 9.95, 8.37, 6.01, 11.81 and 10.96, respectively. Modified NR foam had high oil absorption capacity, reusability, easy to use and good environmental friendly. It can be used as an alternative sorbent material for oil spill cleanup.

A new kind of natural rubber-based oil sorbent material was prepared by sulfur vulcanization system. Natural rubber (NR) foam was modified with poly(butyl methacrylate) (PBMA) and poly(butyl acrylate) (PBA) which were prepared by emulsion polymerization. The functionality of pure polyacrylate and modified NR foam were characterized by Fourier transform infrared (FTIR) spectroscopy. Morphology of the modified NR foam was observed by scanning electron microscope (SEM). The oil/water sorption capacity and reusability of modified NR foam were investigated. Sorption test of modified NR foam showed that the modified NR foam were efficiently removed petroleum-based liquid (viscosities of 0.49-37 cSt) such as gasohol, diesel, engine oil, xylene and toluene. The oil sorption capacity of modified NR foam was in the range of 5-16 g g À1 and maintained oil sorption capacity over the range of 3-15 g g À1 after 20 cycles of absorption. About 95% of foam can be recovered by squeezing or evaporating the oil or organic solvent within the modified NR foam. The results showed that the modified NR foams are promised as reusable oil sorbent.

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A variety of initiator fragments end-capped oligomers [X ∼ (M) n ∼ X; M = N, N-dimethylacrylamide (DMAA), acrylic acid (ACA), N-(1,1-dimethyl-3-oxobutyl)acrylamide (DOBAA), and acryloylmorpholine (ACMO); X = initiator fragments] were synthesized by oligomerization of the corresponding monomers catalyzed by the radical initiators such as ammonium persulfate ( A P S ) , 2 , 2 ′ -a z o b i s ( 2 -m e t h y l -N -( 2 -h y d r o x y e thyl)propionamide) (VA-086), and azobisisobutyronitrile (AIBN). These initiator fragments end-capped oligomers were found to cause a gelation toward not only water but also traditional organic media such as methanol, 2-propanol, propylene carbonate, 1,2-dichloroethane, and tetrahydrofuran. These obtained oligomers were applied to the nanocomposite reactions with silica nanoparticles in the presence of tetraethoxysilane (TEOS) under alkaline conditions to provide the corresponding oligomers/ silica nanocomposites. In these nanocomposites, X ∼ (M) n ∼ X/SiO 2 nanocomposites, which were prepared by using APS as an initiator, were found to afford the clear weight loss in proportion to the contents of the oligomers in the composites after calcination at 800°C. However, interestingly, X ∼ (M) n ∼ X/SiO 2 nanocomposites, which were prepared by using VA-086 and AIBN, afforded no weight loss corresponding to the contents of the oligomers in the composites even after calcination at 800°C.