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RISS 인기검색어
- 검색키워드
- 저자 : Zibiao Li (검색결과 2 건)
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Li, Zibiao,Zhang, Zhongxing,Liu, Kerh Li,Ni, Xiping,Li, Jun American Chemical Society 2012 Biomacromolecules Vol.13 No.12
<P>This paper reports the synthesis and characterization of new hyperbranched amphiphilic polyurethane multiblock copolymers consisting of poly(propylene glycol) (PPG), poly(ethylene glycol) (PEG), and polycaprolactone (PCL) segments as <I>in situ</I> thermogels. The hyperbranched poly(PPG/PEG/PCL urethane)s, termed as HBPEC copolymers, were synthesized from PPG-diol, PEG-diol, and PCL-triol by using 1,6-hexamethylene diisocyanate (HMDI) as a coupling agent. The compositions and structures of HBPEC copolymers were determined by GPC and <SUP>1</SUP>H NMR spectroscopy. We carried out comparative studies of the new hyperbranched copolymers with their linear counterparts, the linear poly(PPG/PEG/PCL urethane) (LPEC) copolymer and Pluronic F127 PEG-PPG-PEG block copolymer, in terms of their self-assembly and aggregation behaviors and thermoresponsive properties. HBPEC copolymers were found to show thermoresponsive micelle formation and aggregation behaviors. Particularly, the lower critical solution temperature (LCST) of the copolymers was significantly affected by the copolymer architecture. HBPEC copolymers showed much lower LCST than LPEC, the linear counterpart. Our studies revealed that the effect of hyperbranch architecture was more prominent in the gelation of the copolymers. The aqueous solutions of HBPEC copolymers exhibited thermogelling behaviors at critical gelation concentrations (CGCs) ranging from 4.3 to 7.4 wt %. These values are much lower than those reported on other PCL-contained linear thermogelling copolymers and Pluronic F127 copolymer. In addition, the CGC of HBPEC copolymers is much lower than the control LPEC copolymer. More interestingly, at high temperatures, while LPEC and other linear thermogelling copolymers formed turbid sol, HBPEC formed a dehydrated gel. Our data suggest that these phenomena are caused by the hyperbranched structure of HBPEC copolymers, which could increase the interaction of copolymer branches and enhance the chain association through synergetic hydrogen bonding effect. The thermogelling behavior of HBPEC block copolymers was further evidenced by the <SUP>1</SUP>H NMR molecular dynamic study and rheological study, which further support the above hypothesis. The hydrolytic degradation study showed that the HBPEC copolymer hydrogels are biodegradable under physiological conditions. Together with the good cell biocompatibility demonstrated by the cytotoxicity study, the new thermogelling copolymers reported in this paper could potentially be used as <I>in situ</I>-forming hydrogels for biomedical applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bomaf6/2012/bomaf6.2012.13.issue-12/bm3012506/production/images/medium/bm-2012-012506_0017.gif'></P>
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Jiaxin Xu,Yuan Tian,Zibiao Li,Beng Hoon Tan,Karen Yuanting Tang,Kam Chiu Tam 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-
Trace amounts of pharmaceuticals and personal care products (PPCPs) are found in our water systems,and they are known to have adverse effects on wildlife and human at the ng/L to lg/L range, belowthe detection limit of most water analytical instruments. Methacrylate acid (MAA)-ethyl acrylate (EA)colloidal scaffolds were prepared via emulsion polymerization and used as templates for the in-situco-precipitation of Fe2+ to produce stable functional magnetic nanoparticles (MNPs) (<500 nm) decoratedwith b-cyclodextrin (b-CD) (FMNP). Emulsion polymerization with the controlled addition of monomermixtures allowed for good size control, and silica coating was introduced to prevent the oxidation ofFMNP. The superparamagnetic FMNP with high saturation magnetization (33 emu/g) could be readilyseparated from water using a high gradient magnetic separator (HGMS). Procaine hydrochloride (PrHy)was used as a model pharmaceutical residue to evaluate the performance of the FMNP, and 53.65 mgPrHy/g FMNP was absorbed using 600 ppm FMNP. A fast (30 min) adsorption kinetic follows thePseudo-first-order kinetic model that described the physical adsorption through a 1 to 1 host–guestinclusion mechanism. And the adsorption behavior followed the Freundlich isotherm with a linearadsorption performance. The proposed system is scalable and adaptable to existing water treatment processes,and it can be used for the detection of low concentration pharmaceuticals via a pre-concentratingstrategy.
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