聚2-甲基丙烯酰氧基乙基磷酰胆碱改性聚合物研究

聚2-甲基丙烯酰氧基乙基磷酰胆碱(PMPC)是一种具有极强亲水性和生物相容性的聚合物。通过PMPC改性材料表面获得生物相容性较好的生物医用材料已成为研究重点之一。综述了PMPC的合成方法以及PMPC改性聚合物的主要接枝方法,并展望了磷酰胆碱类聚合物的发展以及应用前景。     

Telechelic polymers by living and controlled/living polymerization methods

Telechelic polymers, defined as macromolecules that contain two reactive end groups, are used as cross-linkers, chain extenders, and important building blocks for various macromolecular structures, including block and graft copolymers, star, hyperbranched or dendritic polymers. This review article describes the general techniques for the preparation of telechelic polymers by living and controlled/living polymerization methods; namely atom transfer radical polymerization, nitroxide mediated radical polymerization, reversible addition-fragmentation chain transfer polymerization, iniferters, iodine transfer polymerization, cobalt mediated radical polymerization, organotellurium-, organostibine-, organobismuthine-mediated living radical polymerization, living anionic polymerization, living cationic polymerization, and ring opening metathesis polymerization. The efficient click reactions for the synthesis of telechelic polymers are also presented.     

Poly[2-(methacryloyloxy)ethyl phosphorylcholine]-Stabilized graphene-iron oxide composites for water splitting

The electrolysis of water is considered as a potentially realistic technology for the massive production of hydrogen. The use of graphene composites in electrocatalytic water splitting has been extensively investigated. Graphene-iron oxide composites were prepared via in situ polymerization of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and poly (ethylene glycol) monomethacrylate (PEG) on graphene surface (non-oxidative graphite-HOPG/G) in presence of iron oxide nanoparticles (IONPs) and denoted as G-INSCP. Copolymers PMPC-co-PEG (CP) and block copolymer PMPC-b-PEG (BCP) were prepared and their structures were thoroughly characterized. These polymers were used to prepare G-INSCP, G-CP, and G-BCP, their stabilities were compared and their morphologies were studied. HOPG, G-CP, and G-INSCP were used in the hydrogen evolution reaction (HER) as effective platinum catalyst alternatives. G-BCP composite was excluded owing to its very low stability. To evaluate the performance of these electrocatalysts in acidic media, linear sweep voltammetry and electrochemical impedance spectroscopy were employed. Results revealed that, compared with HOPG and G-CP, G-INSCP exhibited a significantly improved catalytic activity with respect to HER in an acidic electrolyte. Additionally, at a current density of 10 mA cm^?2, G-INSCP demonstrated a lower overpotential and Tafel slope of 95 mV_RHE and 67 mV dec^?1, respectively. These observations were attributed to the synergistic effect between the magnetic IONPs and PMPC polymer along with the increase in the electron transfer rate owing to the conductive graphene in the catalyst. Thus G-INSCP catalyst can be a potential candidate for HER and paving the way for the advancement of new and similar catalysts for other applications.     

A cost analysis model for heavy equipment

Total cost is one of the most important factors for a heavy equipment product purchase decision. However, the different cost views and perspectives of performance expectations between the different involved stakeholders may cause customer relation problems between the manufacturers and customers. Beginning with the conventional manufacturers’ cost view, this paper presents the necessity and importance of expanding the heavy equipment manufacturers’ cost scope to include the post-manufacturing customer stage of their products. Then, this paper narrates a general mathematics Post-Manufacturing Product Cost (PMPC) model to analyze the total costs of heavy equipment in its utilization stage. A major emphasis of the PMPC model is placed on the strategy of improving the manufacturers product cost management and the strategy of customers purchasing decisions cost management and their interdependencies as related to their specific different perspectives on the product utilization patterns.