Both four-ann star-shaped poly(ε-caprolactone) (4sPCL) and two-ann linear PCL (2LPCL) were synthesized and their inclusion complexation with α-cyclodextrin (α-CD) were studied. The inclusion complexes (ICs...Both four-ann star-shaped poly(ε-caprolactone) (4sPCL) and two-ann linear PCL (2LPCL) were synthesized and their inclusion complexation with α-cyclodextrin (α-CD) were studied. The inclusion complexes (ICs) formed between the PCL polymers and α-CD were characterized by ^1H-NMR, DSC, TGA, WAXD, and FT-1R, respectively. Both branch ann number and molecular weight of the PCL polymers have apparent effect on the stoichiometry (CL:CD, mol:mol) of these ICs. All these analytical results indicate that the branch arms of the PCL polymers are incorporated into the hydrophobic α-CD cavities and their original crystalline properties are completely suppressed. Moreover, the inclusion complexation between two-ann linear or four-ann star-shaped PCL polymers and α-CD not only enhances the thermal stability of the guest PCL polymers but also improves that of α-CD.展开更多
An aromatic heterocyclic Schiff base neodymium complex bearing thiazole was synthesized and its activity in the ring-opening polymerization ofε-caprolactone(CL)was examined.The conditions of the CL/Nd molar ratio,mon...An aromatic heterocyclic Schiff base neodymium complex bearing thiazole was synthesized and its activity in the ring-opening polymerization ofε-caprolactone(CL)was examined.The conditions of the CL/Nd molar ratio,monomer concentration,polymerization time and temperature were investigated.Activities of ca.171 kg/Nd·h were obtained under the optimum condition(CL/Nd=1600(molar ratio),[CL]=2.26 mol L^(-1),1 h at 50℃),giving a poly(ε-caprolactone)(PCL)of number-average molecular weight M_n=5.4×10~4 and molecular...展开更多
A new method to synthesize a degradable terminal amino group-containing copolymer,poly(ethylene glycol)-b- poly(ε-caprolactone)(MPEG-PCL-NH_2),was developed in the following three steps:(1)the ring-opening polymeriza...A new method to synthesize a degradable terminal amino group-containing copolymer,poly(ethylene glycol)-b- poly(ε-caprolactone)(MPEG-PCL-NH_2),was developed in the following three steps:(1)the ring-opening polymerization (ROP)ofε-caprolactone from the Schiff base prepared from benzatdehyde and ethanolamine(Ph-CH=NCH_2CH_2OH)used as an initiator to obtain heterobifunctional poly(ε-caprolactone)with one terminal Schiff base group and one hydroxyl group (HO-PCL-CH_2CH_2N=CH-Ph);(2)the coupling reaction of two ...展开更多
Branched poly(ε-capmlactone) was synthesized by self-condensing atom transfer radical polymerization of macroinimer, α-acryloyoxy-ω-2-bromopropionyloxy poly(ε-caprolactone), which was prepared by enzyme-cataly...Branched poly(ε-capmlactone) was synthesized by self-condensing atom transfer radical polymerization of macroinimer, α-acryloyoxy-ω-2-bromopropionyloxy poly(ε-caprolactone), which was prepared by enzyme-catalyzed ring-opening polymerization of ε-caprolactone with 2-hydroxylethyl acrylate as initiator and esterification of the ω-hydroxyl group of the obtained poly(ε-caprolactone) by 2-bromopropionyl bromide.展开更多
We have investigated the crystallization and morphological behaviors of poly(ε-caprolactone)-b-poly(L-lactide) (PCL-b-PLLA) in its autophobic dewetted ultrathin films (-11 nm) using atomic force microscopy (...We have investigated the crystallization and morphological behaviors of poly(ε-caprolactone)-b-poly(L-lactide) (PCL-b-PLLA) in its autophobic dewetted ultrathin films (-11 nm) using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The autophobic dewetting process creates a well defined film geometry containing an extremely thin wetting layer (-4.5 nm) with densely distributed micrometer droplets atop, which re- stricts the primary nucleation process to occurring only in the droplets. In addition to the normally encountered flat-on lamellae, the growth of edge-on lamellae in such a thin wetting layer has been observed on both of two crys- tallization paths. In thermal crystallization, flat-on lamellae are favored at small supercoolings while edge-on la- mellae appear at very large supercoolings both in the droplets and the wetting layer. For cold crystallization, the edge-on lamellae can form easily in the droplets and grow into the wetting layer even at very small supercoolings. These observations are explained on the basis that the nucleation and lamellar orientation are strongly affected by the film geometry, the crystallization paths, and the applied supercoolings.展开更多
Inspired by the concept of "polymer-in-ceramic",a composite poly(ε-caprolactone)(PCL)/ceramic containing LiTFSI is prepared and investigated as a solid electrolyte for all-solid-state batteries.The composit...Inspired by the concept of "polymer-in-ceramic",a composite poly(ε-caprolactone)(PCL)/ceramic containing LiTFSI is prepared and investigated as a solid electrolyte for all-solid-state batteries.The composite with the optimum concentration of 45 wt% LiTFSI and 75 wt% Li1.5Al0.5Ge1.5(PO4)3(LAGP,NASICON-type structure) exhibits a high ionic conductivity(σi=0.17 mS cm-1) at 30℃,a transference number of 0.30,and is stable up to 5.0 V.The composite electrolyte is a flexible and self-standing membrane.Solid-state LiFePO4//Li batteries with this composite electrolyte demonstrate excellent cycling stability with high discharge capacity of 157 mA h g-1,high capacity retention of 96% and coulombic efficiency of 98.5% after 130 cycles at 30℃ and 0.1 C rate.These electrochemical properties are better than other PCL-based allsolid-lithium batteries,and validate the concept of "polymer-in-ceramic" by avoiding the drawback of lower conductivity in prior "polymer-in-ceramic" electrolyte at high concentration of the ceramic.展开更多
Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting route.Firstly,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprola...Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting route.Firstly,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprolactone (ε-CL) with tin (Ⅱ) 2-ethylhexanoate as catalyst and n-butyl alcohol as initiator.Secondly,the PCL reacted with isophorone diisocyanate (IPDI) to prepare PCL with isocyanate functional group (PCL-NCO).Hydroxylamine was used to degrade gelatin by the cleavage between asparagine and glycine residues of gelatin.PCL-NCO reacted with the hydroxyl/amino groups of degraded gelatin in a homogeneous system and yielded the PCL modified gelatin copolymers.The gelatin grafted PCL copolymers were measured by means of XRD,FTIR,DSC and 1 H NMR.The results confirmed the conjugation of PCL onto gelatin chains.The PCL modified gelatin can be used as biomaterials owing to their biocompatibility and biodegradation.展开更多
The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficien...The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficient biomechanical properties,blended films composed of silk fibroin( SF) and poly( ε-caprolactone)( PCL) were fabricated by electrospinning in this study. Scanning electron microscope( SEM), X-ray diffraction( XRD),thermal analysis,Fourier transform-infrared( FT-IR),Raman spectra,mechanical testing,and water solubility were used to characterize the morphological, structural and mechanical properties of the blended electrospinning films. Results showed that the diameter of the blended fiber was distributed between 600 and1000 nm,and the fiber diameter increased as the PCL content increased. There is no obvious phase separation due to the similarity and intermiscibility,as well as the interactions( mainly hydrogen bonds), between the two polymers. Meanwhile, the secondary structures of SF changed from random coils and Silk I to Silk II because of the interactions between SF and PCL. For this reason,the tensile strength and elongation at break of the electrospinning films improved significantly,and the water solubility decreased. In conclusion,the blended electrospinning films fabricated in this study showed satisfying mechanical properties and water insolubilities,and they may be promising biomaterials for applications in tissue engineering for blood vessels,nerve conduits,tendons,ligaments and other tissues.展开更多
Recent studies have shown the potential of artificially synthesized conduits in the repair of peripheral nerve injury.Natural biopolymers have received much attention because of their biocompatibility.To investigate t...Recent studies have shown the potential of artificially synthesized conduits in the repair of peripheral nerve injury.Natural biopolymers have received much attention because of their biocompatibility.To investigate the effects of novel electrospun absorbable poly(ε-caprolactone)/type I collagen nanofiber conduits(biopolymer nanofiber conduits)on the repair of peripheral nerve injury,we bridged 10-mm-long sciatic nerve defects with electrospun absorbable biopolymer nanofiber conduits,poly(ε-caprolactone)or silicone conduits in Sprague-Dawley rats.Rat neurologica1 function was weekly evaluated using sciatic function index within 8 weeks after repair.Eight weeks after repair,sciatic nerve myelin sheaths and axon morphology were observed by osmium tetroxide staining,hematoxylin-eosin staining,and transmission electron microscopy.S-100(Schwann cell marker)and CD4(inflammatory marker)immunoreactivities in sciatic nerve were detected by immunohistochemistry.In rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits,no serious inflammatory reactions were observed in rat hind limbs,the morphology of myelin sheaths in the injured sciatic nerve was close to normal.CD4 immunoreactivity was obviously weaker in rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits than in those subjected to repair with poly(ε-caprolactone)or silicone.Rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits tended to have greater sciatic nerve function recovery than those receiving poly(ε-caprolactone)or silicone repair.These results suggest that electrospun absorbable poly(ε-caprolactone)/type I collagen nanofiber conduits have the potential of repairing sciatic nerve defects and exhibit good biocompatibility.All experimental procedures were approved by Institutional Animal Care and Use Committee of Taichung Veteran General Hospital,Taiwan,China(La-1031218)on October 2,2014.展开更多
Ring-opening polymerization of ε-caprolactone has been carried out by using rare earth Schiff base complexes: lanthanide tris(N-phenyl-3,5-di-t-butylsalicylaldiminato)s [Ln(OPBS)3] as single component catalyst f...Ring-opening polymerization of ε-caprolactone has been carried out by using rare earth Schiff base complexes: lanthanide tris(N-phenyl-3,5-di-t-butylsalicylaldiminato)s [Ln(OPBS)3] as single component catalyst for the first time. The influences of different rare earth elements, monomer and catalyst concentration as well as reaction time on the polymerization were investigated. Mechanism studies showed that monomer inserts into the active site with the acyl-oxygen bond scission rather than the break of alkyl-oxygen bond.展开更多
Tetrahydrosalen ligand was employed in the synthesis of gadolinium complex. The ligand was deprotoned by LiBu, and the afforded lithium salt was reacted with anhydrous GdCl3 to produce the gadolinium complex through s...Tetrahydrosalen ligand was employed in the synthesis of gadolinium complex. The ligand was deprotoned by LiBu, and the afforded lithium salt was reacted with anhydrous GdCl3 to produce the gadolinium complex through salt metathesis. This complex was successfully used to initiate the ring-opening polymerization of ε-caprolactone. The initiation conditions in different temperature, monomer-to-initiator ratio and time were investigated. Under the condition: [ε-caprolactone]:[catalyst] = 600, 56 ℃, toluene: 2 ml, poly(ε-caprolactone) (PCL) with Mw = 11,2782 and PDI = 1.96 was achieved.展开更多
Block copolyesters of L-lactide and ε-caprolactone were synthesized by melt copolymerization of ε-caprolactone and L-lactide.The degradation performance of copolyesters was investigated by quartz crystal microbalanc...Block copolyesters of L-lactide and ε-caprolactone were synthesized by melt copolymerization of ε-caprolactone and L-lactide.The degradation performance of copolyesters was investigated by quartz crystal microbalance with dissipation(QCM-D).Diisocyanate terminated copolyesters could obtain via the reaction of copolyesters and diisocyanate.Diisocyanate terminated copolyesters could react with polyol resin to prepare degradable polyurethane which can be used in antifouling coatings.In this paper,we also discussed the degradation products release action and antifouling performance of the copolyesters film.展开更多
The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers w...The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers were developed for potential small-diameter blood vessel applications. CS is a positively charged polymer which is beneficial for cell attachment and growth,while PLCL provides favorable mechanical support due to its excellent elasticity. Typical nanofibrous structure was observed in both CS/PLCL and pure PLCL scaffolds. The optimal mechanical property could be achieved when the weight ratio of CS/PLCL was 1 ∶ 2.Compared with pure PLCL scaffolds, the CS/PLCL scaffolds showed higher hydrophilicity and markedly promoted the attachment,spreading and proliferation of human umbilical vein endothelial cells( HUVECs). Hence,CS/PLCL scaffolds can be used as potential vascular grafts.展开更多
Transesterification of poly(ethylene terephthalate) (PET) with poly(ε-caprolactone) (PCL) was investigated bymeans of NMR spectroscopy, extraction experiments, differential scanning calorimetry (DSC) and ph...Transesterification of poly(ethylene terephthalate) (PET) with poly(ε-caprolactone) (PCL) was investigated bymeans of NMR spectroscopy, extraction experiments, differential scanning calorimetry (DSC) and phase contrast microscopy(PCM). The;H-NMR results show that transesterification takes place in the melt blends and leads to the formation of thePET-PCL copolyester with a chemical structure similar to ethylene terephthalate-ε-caprolactonc copolycster (TCL)synthesized directly from monomers. However, even in the blend that has been transesterified for 8 h, the random PET-PCLcopolyester, PET-PCL copolyester with long PET or long PCL segments and the unreacted PET and PCL homopolymersmay coexist. Due to the low mobility of PET and PCL chains and the high viscosity of the two macromolecules, thetransesterification proceeds with difficulty. Furthermore, PET is incompatible with PCL, the transesterification can onlyoccur at the interface or in the interfacial region between two phases, and finally the reaction can only reach a localequilibrium. These results indicate that in fact the transesterification in the melt blend between two incompatiblehomopolymers could not lead to the formation of completely random or typical block copolyesters.展开更多
Electron microscope and electron diffraction have been used to study epitaxial crystallization of poly(ε-caprolactone)(PCL).on highly oriented film of isotactic polypropylene(iPP).The results obtained from bright fie...Electron microscope and electron diffraction have been used to study epitaxial crystallization of poly(ε-caprolactone)(PCL).on highly oriented film of isotactic polypropylene(iPP).The results obtained from bright field(BF)electron micrograph and electron diffraction indicate that the PCL can epitaxially grow on iPP substrate and form cross-hatched lamellar texture.The c axes of PCL are ±500 apart from the c axes of iPP. The contact planes of the two kinds of crystals are(010)of iPP and(100) of PCL,respectively.展开更多
A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ~ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiato...A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ~ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL pre-polymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide(A) to PCL pre-polymer(BB). The block copolymers were characterized by ~ 1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.展开更多
Poly(ε-caprolactone) (PCL) with different molecular weights was synthesized and characterized by a gelpermeation chromatograph equipped with multiple detector. The melting behavior of PCL was also studied. It was fou...Poly(ε-caprolactone) (PCL) with different molecular weights was synthesized and characterized by a gelpermeation chromatograph equipped with multiple detector. The melting behavior of PCL was also studied. It was found thatthe equilibrium melting points (T_m^0) of PCL samples depend on their molecular weights. Wide angle X-ray diffractionmeasurements (WAXD) and DSC measurements showed that the crystals of the high molecular weight PCLs were moreperfect than those of the low molecular weigh ones. These results demonstrate that the concentration of the end groups ofPCL chains is the main factor that influences the melting behavior. The fusion enthalpy per repeating unit (ΔH_u) wasdetermined to be 11.3 kJ/mol for PCL.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 20404007).
文摘Both four-ann star-shaped poly(ε-caprolactone) (4sPCL) and two-ann linear PCL (2LPCL) were synthesized and their inclusion complexation with α-cyclodextrin (α-CD) were studied. The inclusion complexes (ICs) formed between the PCL polymers and α-CD were characterized by ^1H-NMR, DSC, TGA, WAXD, and FT-1R, respectively. Both branch ann number and molecular weight of the PCL polymers have apparent effect on the stoichiometry (CL:CD, mol:mol) of these ICs. All these analytical results indicate that the branch arms of the PCL polymers are incorporated into the hydrophobic α-CD cavities and their original crystalline properties are completely suppressed. Moreover, the inclusion complexation between two-ann linear or four-ann star-shaped PCL polymers and α-CD not only enhances the thermal stability of the guest PCL polymers but also improves that of α-CD.
基金the National Natural Science Foundation of China(No.20774078)the Key Program of the National Natural Science Foundation of China(No.20434020)the Special Funds for Major Basic Research Projects(No.G 2005CB623802)
文摘An aromatic heterocyclic Schiff base neodymium complex bearing thiazole was synthesized and its activity in the ring-opening polymerization ofε-caprolactone(CL)was examined.The conditions of the CL/Nd molar ratio,monomer concentration,polymerization time and temperature were investigated.Activities of ca.171 kg/Nd·h were obtained under the optimum condition(CL/Nd=1600(molar ratio),[CL]=2.26 mol L^(-1),1 h at 50℃),giving a poly(ε-caprolactone)(PCL)of number-average molecular weight M_n=5.4×10~4 and molecular...
基金the National Natural Science Foundation of China(No.20574066)National Fund for Distinguished Young Scholar(No.50425309)
文摘A new method to synthesize a degradable terminal amino group-containing copolymer,poly(ethylene glycol)-b- poly(ε-caprolactone)(MPEG-PCL-NH_2),was developed in the following three steps:(1)the ring-opening polymerization (ROP)ofε-caprolactone from the Schiff base prepared from benzatdehyde and ethanolamine(Ph-CH=NCH_2CH_2OH)used as an initiator to obtain heterobifunctional poly(ε-caprolactone)with one terminal Schiff base group and one hydroxyl group (HO-PCL-CH_2CH_2N=CH-Ph);(2)the coupling reaction of two ...
文摘Branched poly(ε-capmlactone) was synthesized by self-condensing atom transfer radical polymerization of macroinimer, α-acryloyoxy-ω-2-bromopropionyloxy poly(ε-caprolactone), which was prepared by enzyme-catalyzed ring-opening polymerization of ε-caprolactone with 2-hydroxylethyl acrylate as initiator and esterification of the ω-hydroxyl group of the obtained poly(ε-caprolactone) by 2-bromopropionyl bromide.
文摘We have investigated the crystallization and morphological behaviors of poly(ε-caprolactone)-b-poly(L-lactide) (PCL-b-PLLA) in its autophobic dewetted ultrathin films (-11 nm) using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The autophobic dewetting process creates a well defined film geometry containing an extremely thin wetting layer (-4.5 nm) with densely distributed micrometer droplets atop, which re- stricts the primary nucleation process to occurring only in the droplets. In addition to the normally encountered flat-on lamellae, the growth of edge-on lamellae in such a thin wetting layer has been observed on both of two crys- tallization paths. In thermal crystallization, flat-on lamellae are favored at small supercoolings while edge-on la- mellae appear at very large supercoolings both in the droplets and the wetting layer. For cold crystallization, the edge-on lamellae can form easily in the droplets and grow into the wetting layer even at very small supercoolings. These observations are explained on the basis that the nucleation and lamellar orientation are strongly affected by the film geometry, the crystallization paths, and the applied supercoolings.
基金supported by the National Key R&D Program of China (2016YFB0100500)Special fund of key technology research and development projects (20180201097GX) (20180201099GX) (20180201096GX) (20190302130GX)+1 种基金Jilin province science and technology department. The R&D Program of power batteries with low temperature and high energy, Science and Technology Bureau of Changchun (19SS013)Key Subject Construction of Physical Chemistry of Northeast Normal University。
文摘Inspired by the concept of "polymer-in-ceramic",a composite poly(ε-caprolactone)(PCL)/ceramic containing LiTFSI is prepared and investigated as a solid electrolyte for all-solid-state batteries.The composite with the optimum concentration of 45 wt% LiTFSI and 75 wt% Li1.5Al0.5Ge1.5(PO4)3(LAGP,NASICON-type structure) exhibits a high ionic conductivity(σi=0.17 mS cm-1) at 30℃,a transference number of 0.30,and is stable up to 5.0 V.The composite electrolyte is a flexible and self-standing membrane.Solid-state LiFePO4//Li batteries with this composite electrolyte demonstrate excellent cycling stability with high discharge capacity of 157 mA h g-1,high capacity retention of 96% and coulombic efficiency of 98.5% after 130 cycles at 30℃ and 0.1 C rate.These electrochemical properties are better than other PCL-based allsolid-lithium batteries,and validate the concept of "polymer-in-ceramic" by avoiding the drawback of lower conductivity in prior "polymer-in-ceramic" electrolyte at high concentration of the ceramic.
基金Supported by International Cooperation from Ministry of Science and Technology of China(No.2008DFA51170)
文摘Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting route.Firstly,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprolactone (ε-CL) with tin (Ⅱ) 2-ethylhexanoate as catalyst and n-butyl alcohol as initiator.Secondly,the PCL reacted with isophorone diisocyanate (IPDI) to prepare PCL with isocyanate functional group (PCL-NCO).Hydroxylamine was used to degrade gelatin by the cleavage between asparagine and glycine residues of gelatin.PCL-NCO reacted with the hydroxyl/amino groups of degraded gelatin in a homogeneous system and yielded the PCL modified gelatin copolymers.The gelatin grafted PCL copolymers were measured by means of XRD,FTIR,DSC and 1 H NMR.The results confirmed the conjugation of PCL onto gelatin chains.The PCL modified gelatin can be used as biomaterials owing to their biocompatibility and biodegradation.
基金National Natural Science Foundations of China(No.30970714,No.51103092)Natural Science Foundation of Jiangsu Province,China(No.BK2012634)+1 种基金College Natural Science Research Project of Jiangsu Province,China(No.12KJA430003)Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficient biomechanical properties,blended films composed of silk fibroin( SF) and poly( ε-caprolactone)( PCL) were fabricated by electrospinning in this study. Scanning electron microscope( SEM), X-ray diffraction( XRD),thermal analysis,Fourier transform-infrared( FT-IR),Raman spectra,mechanical testing,and water solubility were used to characterize the morphological, structural and mechanical properties of the blended electrospinning films. Results showed that the diameter of the blended fiber was distributed between 600 and1000 nm,and the fiber diameter increased as the PCL content increased. There is no obvious phase separation due to the similarity and intermiscibility,as well as the interactions( mainly hydrogen bonds), between the two polymers. Meanwhile, the secondary structures of SF changed from random coils and Silk I to Silk II because of the interactions between SF and PCL. For this reason,the tensile strength and elongation at break of the electrospinning films improved significantly,and the water solubility decreased. In conclusion,the blended electrospinning films fabricated in this study showed satisfying mechanical properties and water insolubilities,and they may be promising biomaterials for applications in tissue engineering for blood vessels,nerve conduits,tendons,ligaments and other tissues.
基金supported by grants from the Taichung Veterans General Hospital and Central Taiwan University of Science and Technology,No.TCVGH-CTUST1047701(to CCS and BSL)Taichung Veterans General Hospital,No.TCVGH-1034907C(to CCS),Taiwan,China
文摘Recent studies have shown the potential of artificially synthesized conduits in the repair of peripheral nerve injury.Natural biopolymers have received much attention because of their biocompatibility.To investigate the effects of novel electrospun absorbable poly(ε-caprolactone)/type I collagen nanofiber conduits(biopolymer nanofiber conduits)on the repair of peripheral nerve injury,we bridged 10-mm-long sciatic nerve defects with electrospun absorbable biopolymer nanofiber conduits,poly(ε-caprolactone)or silicone conduits in Sprague-Dawley rats.Rat neurologica1 function was weekly evaluated using sciatic function index within 8 weeks after repair.Eight weeks after repair,sciatic nerve myelin sheaths and axon morphology were observed by osmium tetroxide staining,hematoxylin-eosin staining,and transmission electron microscopy.S-100(Schwann cell marker)and CD4(inflammatory marker)immunoreactivities in sciatic nerve were detected by immunohistochemistry.In rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits,no serious inflammatory reactions were observed in rat hind limbs,the morphology of myelin sheaths in the injured sciatic nerve was close to normal.CD4 immunoreactivity was obviously weaker in rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits than in those subjected to repair with poly(ε-caprolactone)or silicone.Rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits tended to have greater sciatic nerve function recovery than those receiving poly(ε-caprolactone)or silicone repair.These results suggest that electrospun absorbable poly(ε-caprolactone)/type I collagen nanofiber conduits have the potential of repairing sciatic nerve defects and exhibit good biocompatibility.All experimental procedures were approved by Institutional Animal Care and Use Committee of Taichung Veteran General Hospital,Taiwan,China(La-1031218)on October 2,2014.
基金This work was financially supported by the Key Program of National Natural Science Foundation of China(No.G 20434020)the Special Funds for Major Basic Research Projects(No.G 2005 CB623802)the Committee of Science and Technology of Zhejiang Province.
文摘Ring-opening polymerization of ε-caprolactone has been carried out by using rare earth Schiff base complexes: lanthanide tris(N-phenyl-3,5-di-t-butylsalicylaldiminato)s [Ln(OPBS)3] as single component catalyst for the first time. The influences of different rare earth elements, monomer and catalyst concentration as well as reaction time on the polymerization were investigated. Mechanism studies showed that monomer inserts into the active site with the acyl-oxygen bond scission rather than the break of alkyl-oxygen bond.
基金The authors acknowledge the financial supports from National Nature Science Foundation(Nos. 20674071, 20774078 and 20434020) ;the Special Funds for Major State Basic Research Projects (No.2005CB623802).
文摘Tetrahydrosalen ligand was employed in the synthesis of gadolinium complex. The ligand was deprotoned by LiBu, and the afforded lithium salt was reacted with anhydrous GdCl3 to produce the gadolinium complex through salt metathesis. This complex was successfully used to initiate the ring-opening polymerization of ε-caprolactone. The initiation conditions in different temperature, monomer-to-initiator ratio and time were investigated. Under the condition: [ε-caprolactone]:[catalyst] = 600, 56 ℃, toluene: 2 ml, poly(ε-caprolactone) (PCL) with Mw = 11,2782 and PDI = 1.96 was achieved.
基金Supported by the National Natural Science Foundation of China( No.2 0 174 0 33and2 0 2 5 4 0 0 1) and the Ministry of Sci-ence and Technology of China( No.19990 6 4 80 1)
文摘Block copolyesters of L-lactide and ε-caprolactone were synthesized by melt copolymerization of ε-caprolactone and L-lactide.The degradation performance of copolyesters was investigated by quartz crystal microbalance with dissipation(QCM-D).Diisocyanate terminated copolyesters could obtain via the reaction of copolyesters and diisocyanate.Diisocyanate terminated copolyesters could react with polyol resin to prepare degradable polyurethane which can be used in antifouling coatings.In this paper,we also discussed the degradation products release action and antifouling performance of the copolyesters film.
基金National Natural Science Foundations of China(Nos.31771048,31570984,31271028)International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality,China(No.15540723400)Biomedical Textile Materials Science and Technology(111 Project),China(No.B07024)
文摘The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers were developed for potential small-diameter blood vessel applications. CS is a positively charged polymer which is beneficial for cell attachment and growth,while PLCL provides favorable mechanical support due to its excellent elasticity. Typical nanofibrous structure was observed in both CS/PLCL and pure PLCL scaffolds. The optimal mechanical property could be achieved when the weight ratio of CS/PLCL was 1 ∶ 2.Compared with pure PLCL scaffolds, the CS/PLCL scaffolds showed higher hydrophilicity and markedly promoted the attachment,spreading and proliferation of human umbilical vein endothelial cells( HUVECs). Hence,CS/PLCL scaffolds can be used as potential vascular grafts.
基金This project was supported by the National Natural Science Foundation of China and the National Key Projects for Fundamental Research "Macromolecular Condensed State", The State Science and Technology Commission of China.
文摘Transesterification of poly(ethylene terephthalate) (PET) with poly(ε-caprolactone) (PCL) was investigated bymeans of NMR spectroscopy, extraction experiments, differential scanning calorimetry (DSC) and phase contrast microscopy(PCM). The;H-NMR results show that transesterification takes place in the melt blends and leads to the formation of thePET-PCL copolyester with a chemical structure similar to ethylene terephthalate-ε-caprolactonc copolycster (TCL)synthesized directly from monomers. However, even in the blend that has been transesterified for 8 h, the random PET-PCLcopolyester, PET-PCL copolyester with long PET or long PCL segments and the unreacted PET and PCL homopolymersmay coexist. Due to the low mobility of PET and PCL chains and the high viscosity of the two macromolecules, thetransesterification proceeds with difficulty. Furthermore, PET is incompatible with PCL, the transesterification can onlyoccur at the interface or in the interfacial region between two phases, and finally the reaction can only reach a localequilibrium. These results indicate that in fact the transesterification in the melt blend between two incompatiblehomopolymers could not lead to the formation of completely random or typical block copolyesters.
文摘Electron microscope and electron diffraction have been used to study epitaxial crystallization of poly(ε-caprolactone)(PCL).on highly oriented film of isotactic polypropylene(iPP).The results obtained from bright field(BF)electron micrograph and electron diffraction indicate that the PCL can epitaxially grow on iPP substrate and form cross-hatched lamellar texture.The c axes of PCL are ±500 apart from the c axes of iPP. The contact planes of the two kinds of crystals are(010)of iPP and(100) of PCL,respectively.
文摘A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ~ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL pre-polymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide(A) to PCL pre-polymer(BB). The block copolymers were characterized by ~ 1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.
文摘Poly(ε-caprolactone) (PCL) with different molecular weights was synthesized and characterized by a gelpermeation chromatograph equipped with multiple detector. The melting behavior of PCL was also studied. It was found thatthe equilibrium melting points (T_m^0) of PCL samples depend on their molecular weights. Wide angle X-ray diffractionmeasurements (WAXD) and DSC measurements showed that the crystals of the high molecular weight PCLs were moreperfect than those of the low molecular weigh ones. These results demonstrate that the concentration of the end groups ofPCL chains is the main factor that influences the melting behavior. The fusion enthalpy per repeating unit (ΔH_u) wasdetermined to be 11.3 kJ/mol for PCL.