Papers by Keyword: PBA

Abstract: The core-shell structure copolymer of PBA/PS was prepared using pre-emulsion and semi-continues polymerization process. The particle size of core-shell latex and the St conversion of shell monomer were affected by emulsifier, initiator, pH and temperature etc. Meanwhile, the laser particle size analyzer, transmission electron microscope and other test methods were utilized to study latex particle average particle size, size distribution and morphological structure, respectively. The kinetics of polymerization was investigated. Well-defined core-shell structure and narrow particle sizedistribution could be achieved under starved conditions of monomer feeding. By the means of TEM found that PBA/PS latex particles had clearly core/shell morphology.

Abstract: Jiaohua Square Station of Harbin Metro Line 1 is built by PBA method with the existence of No. 7381 air defense tunnel. In order to control the ground settlement during PBA construction, numerical model is performed to analyse the surrounding rock pressure, plastic zone and structure internal force. The result shows the lower pilot headings have stronger impact on existing tunnel than the upper ones in that the lower ones get the loading effect while the upper ones the unloading effect. The internal force of air defense tunnel and ground displacement can be well controlled by reducing the area of lower pilot headings at the stages of pilot heading excavation, but the final surface settlement is unqualified. The scheme of lower big pilot heading in part with the support of portal frame meets the requirement of surface settlement. The in-situ surface settlement and the vault settlement of defense tunnel are essentially consistent with numerical results.

Abstract: Polybutyl acrylate (PBA) grafted alumina nanoparticles were synthesized. Polytetrafluoroethylene (PTFE) nanocomposites reinforced with PBA grafted nanoparticles were prepared by compression molding. The effects of PBA grafted nanoparticles on the tribological behavior of the PTFE nanocomposites were investigated on a tribometer. The abrasion mechanisms of the PTFE nanocomposites were investigated by scanning electron microscopy (SEM) of the abraded surfaces. The results show that the addition of PBA grafted nanoparticles maintains low friction coefficient and improves the wear resistance of the PTFE nanocomposites.

Abstract: This paper describes multi-scale interface for bio and medical engineering based on MEMS technology. MEMS technology can provide various interfaces for biomedical application corresponding to hierarchical components of living organism such as cell, tissue, and organ. This paper mainly deals with small, soft, and safe (S3) micromachine as multi-scale interfaces for medical application. Micromachine is small in nature. S3 micromachine is based on its soft and flexible structure and safe driving principle. These features are suitable for advanced medical tools for minimally invasive medical operations. S3 micromachines-based medical tool has been applied to a retractor for spacing in front of the endoscope at our early stage. This paper also presents the S3 micromachine as a surgical tool for a cell sheet transplantation in an eye.