Novel bio-based and biodegradable block copolymers were synthesized by "click" reaction between poly(L-lactide)(PLLA) and polyamide 4(PA4). Upon tuning the molar mass of PLLA block, the properties of copolym...Novel bio-based and biodegradable block copolymers were synthesized by "click" reaction between poly(L-lactide)(PLLA) and polyamide 4(PA4). Upon tuning the molar mass of PLLA block, the properties of copolymers and electrospun ultrafine fibers were investigated and compared with those of PLLA and PA4 blends. PLLA and PA4 were found incompatible and formed individual crystalline regions, along with reciprocal inhibition in crystallization. Electrospun fibers were highly hydrophobic, even if hydrophilic PA4 was the rich component. The crystallinity of either PLLA or PA4 decreased after electrospinning and PLLA-rich as-spun fibers were almost amorphous. Immersion tests proved that fibers of block copolymers were relatively homogeneous with micro-phase separation between PLLA and PA4. The fibrous structures of copolymers were different from those of the fibers electrospun from blends, for which sheath-core structure induced by macro-phase separation between homopolymers of PLLA and PA4 was confirmed by TEM, EDS, and XPS.展开更多
A novel biodegradable copolymer, poly（5,5-dibromomethyltrimethylene carbonate-co-ε-caprolactone） （poly（DBTC-co-CL）） with pendant bromine groups, was synthesized via ring-opening polymerization （ROP） of ε-cap...A novel biodegradable copolymer, poly（5,5-dibromomethyltrimethylene carbonate-co-ε-caprolactone） （poly（DBTC-co-CL）） with pendant bromine groups, was synthesized via ring-opening polymerization （ROP） of ε-caprolactone （CL） and 5,5- dibromomethyltrimethylene carbonate （DBTC） using stannous octoate （Sn（Oct）2） as catalyst. Then the pendant bromine groups were completely converted into azide form, which permitted ＂click＂ reaction with alkyne-terminated polyethylene （A-PEG） by Huisgen 1,3-dipolar cycloadditions preparing biodegradable amphiphilic poly（DTC-co-CL）-g-PEG graft copolymer. The graft copolymer was characterized by nuclear magnetic resonance （NMR） and size-exclusion chromatography （SEC）.展开更多
X-ray imaging functionalization of biodegradable polyesters is a great demand and challenge in biomedical applications.In this work,a strategy of in-chain functionalization through the combination of ring opening copo...X-ray imaging functionalization of biodegradable polyesters is a great demand and challenge in biomedical applications.In this work,a strategy of in-chain functionalization through the combination of ring opening copolymerization and oxime "Click" postfunctionalization was developed towards X-ray opaque polylactide copolymers.A functionalized cyclic carbonate was first synthesized and used as comonomer of polylactide copolymers,which were subjected to postfunctionalization of oxime "Click" reaction towards iodinated polylactide copolymers.The chemical structure and physical properties of the target products were traced and confirmed.In vitro cytotoxicity evaluation with 3T3-Swiss albino by Alamar blue demonstrated a low cytotoxicity.The X-ray radiopacity was analyzed by Micro-CT and quantified by Hounsfield Units value,which could be tailorable by the feedstock.It is a promising X-ray visible implantable biomaterial in biomedical applications.展开更多
基金financially supported by the National Key Research and Development Program of China (Nos. 2017YFB0309301 and 2017YFB0309302)the Natural Science Foundation of Shanghai, China (No. 17ZR1407200)
文摘Novel bio-based and biodegradable block copolymers were synthesized by "click" reaction between poly(L-lactide)(PLLA) and polyamide 4(PA4). Upon tuning the molar mass of PLLA block, the properties of copolymers and electrospun ultrafine fibers were investigated and compared with those of PLLA and PA4 blends. PLLA and PA4 were found incompatible and formed individual crystalline regions, along with reciprocal inhibition in crystallization. Electrospun fibers were highly hydrophobic, even if hydrophilic PA4 was the rich component. The crystallinity of either PLLA or PA4 decreased after electrospinning and PLLA-rich as-spun fibers were almost amorphous. Immersion tests proved that fibers of block copolymers were relatively homogeneous with micro-phase separation between PLLA and PA4. The fibrous structures of copolymers were different from those of the fibers electrospun from blends, for which sheath-core structure induced by macro-phase separation between homopolymers of PLLA and PA4 was confirmed by TEM, EDS, and XPS.
基金financial supports from the National Natural Science Foundation of China(No. 20704036)special fund from the Major State Basic Research Project(No.2005CB623802)the Committee of Science and Technology of Zhejiang Province
文摘A novel biodegradable copolymer, poly（5,5-dibromomethyltrimethylene carbonate-co-ε-caprolactone） （poly（DBTC-co-CL）） with pendant bromine groups, was synthesized via ring-opening polymerization （ROP） of ε-caprolactone （CL） and 5,5- dibromomethyltrimethylene carbonate （DBTC） using stannous octoate （Sn（Oct）2） as catalyst. Then the pendant bromine groups were completely converted into azide form, which permitted ＂click＂ reaction with alkyne-terminated polyethylene （A-PEG） by Huisgen 1,3-dipolar cycloadditions preparing biodegradable amphiphilic poly（DTC-co-CL）-g-PEG graft copolymer. The graft copolymer was characterized by nuclear magnetic resonance （NMR） and size-exclusion chromatography （SEC）.
基金financially supported by the National Natural Science Foundation of China(No.31500767)the Natural ScienceFoundation of Liaoning Province of China(No.20180510037)the Fundamental Research Funds for the Central Universities(No.DUT19LAB27)。
文摘X-ray imaging functionalization of biodegradable polyesters is a great demand and challenge in biomedical applications.In this work,a strategy of in-chain functionalization through the combination of ring opening copolymerization and oxime "Click" postfunctionalization was developed towards X-ray opaque polylactide copolymers.A functionalized cyclic carbonate was first synthesized and used as comonomer of polylactide copolymers,which were subjected to postfunctionalization of oxime "Click" reaction towards iodinated polylactide copolymers.The chemical structure and physical properties of the target products were traced and confirmed.In vitro cytotoxicity evaluation with 3T3-Swiss albino by Alamar blue demonstrated a low cytotoxicity.The X-ray radiopacity was analyzed by Micro-CT and quantified by Hounsfield Units value,which could be tailorable by the feedstock.It is a promising X-ray visible implantable biomaterial in biomedical applications.
