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Natural rubber (NR) and butyl rubber (IIR) blends were compatibilized by isobutylene-isoprene block copolymer (IIBC) which was specifically synthesized with a relatively high content of isoprene (14.5% mole fraction). Aiming at high damping elastomers, the IIR acts as the high damping phase dispersed in the natural rubber (NR) matrix in this blend. The morphology and microstructure was characterized by atomic force microscope (AFM) and transmission electron microscope (TEM). The results indicated that the IIBC as a compatibilizer could greatly increase the interfacial thickness. Damping property was studied by dynamic mechanical thermal analyzer (DMTA) and rubber processing analyzer (RPA). The results showed that the loss factor greatly increased with adding IIBC, and this may be due to the improved stress transfer promoting the IIR phase to deform and then dissipate energy. The tensile test demonstrated that the tensile strength and modulus increased when 4 parts per hundred rubber [phr] of IIBC was added. Finally, the NR and new NR/IIR isolation bearing samples were prepared and tested on a pressure shear testing machine that could simulate the actual situation during an earthquake.The results showed that hysteretic loss (for one cycle) of the new NR/IIR sample is 83% higher than that of the NR sample, rendering the compatibilized blends potential in isolation rubber bearings application.

Polystyrene nanospheres have been synthesized by atom transfer radical polymerization (ATRP) to control the molecular weight distribution in the aqueous system. The crucial factor in such a system is the ligand that adjusts the solubility of the catalyst in different phases to control the concentration of both the activator and the deactivator in reaction phase. The effect of different ligands including ethylenediamine, 1,10-phenanthroline (phen) and 4,4-dinonyl-2, 2-bipyridyl (dNbpy) on the catalytic solubility in the organic and aqueous phase has been investigated. The molecular weight distribution of polymer obtained in this way was analyzed by gel permeation chromatography (GPC). It showed that the obtained polymer particles presented a broad molecular weight distribution (polydispersity index 1.78) with ethylenediamine as the ligand, but the polymerization rate was high and conversion reached 96.8%. The molecular weight distribution of polystyrene was narrowest with dNbpy as ligand, but the conversion was lowest and only achieved to 69%. Possible reasons were the influence of the structure of three different ligands on the control of ATRP reaction. SEM and GPC indicated that the polystyrene nanospheres presented regular sphere with a diameter of about 120 nm and uniform molecular weight distribution, which possessed a significant potentials in drug carrier field.

Polystyrene nanospheres have been synthesized by atom transfer radical polymerization (ATRP) to control the molecular weight distribution in the aqueous system. The crucial factor in such a system is the ligand that adjusts the solubility of the catalyst in different phases to control the concentration of both the activator and the deactivator in reaction phase. The effect of different ligands including ethylenediamine, 1,10-phenanthroline (phen) and 4,4-dinonyl-2, 2-bipyridyl (dNbpy) on the catalytic solubility in the organic and aqueous phase has been investigated. The molecular weight distribution of polymer obtained in this way was analyzed by gel permeation chromatography (GPC). It showed that the obtained polymer particles presented a broad molecular weight distribution (polydispersity index 1.78) with ethylenediamine as the ligand, but the polymerization rate was high and conversion reached 96.8%. The molecular weight distribution of polystyrene was narrowest with dNbpy as ligand, but the conversion was lowest and only achieved to 69%. Possible reasons were the influence of the structure of three different ligands on the control of ATRP reaction. SEM and GPC indicated that the polystyrene nanospheres presented regular sphere with a diameter of about 120 nm and uniform molecular weight distribution, which possessed a significant potentials in drug carrier field. [ABSTRACT FROM AUTHOR]