Novel polycarbonates from 5-allyloxy-1, 3-dioxan-2-one （ATMC） with 5, 5-dimethyl- 1, 3-dioxan-2-one （DTC） were successfully synthesized for the first time using immobilized porcine pancreas lipase （IPPL） as cata...Novel polycarbonates from 5-allyloxy-1, 3-dioxan-2-one （ATMC） with 5, 5-dimethyl- 1, 3-dioxan-2-one （DTC） were successfully synthesized for the first time using immobilized porcine pancreas lipase （IPPL） as catalyst. The resulting copolymers were characterized by IR, ^1H NMR, ^13C NMR and GPC. The molecular weight （Mn） of the copolymer with molar feed ratio of 10：90 （ATMC：DTC） was 9300 and the polydispersity was 1.31, while the Mn increased to 14300 and polydispersity of 1.25 with the feed ratio of 50：50. Moreover, the composition of the copolymers agreed well with the monomer feed.展开更多
A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation proc...A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation process.The relationship between the anions of the ILs and the catalytic activities was investigated,and the readily‐prepared IL tetraethylammonium imidazolate(TEAI)was found to exhibit the highest catalytic activity.After optimizing the reaction conditions,a PIC with a weight‐average molecular weight(Mw)of25600g/mol was obtained,in conjunction with an isosorbide conversion of92%.As a means of modifying the molecular flexibility and thermal properties of the PIC,poly(aliphatic diol‐co‐isosorbide carbonate)s(PAIC)s were successfully synthesized,again using TEAI,and polymers with Mw values ranging from29000to112000g/mol were obtained.13C NMR analyses determined that the PAIC specimens had random microstructures,while differential scanning calorimetry demonstrated that each of the PAICs were amorphous and had glass transition temperatures ranging from50to115°C.Thermogravimetric analyses found Td‐5%values ranging from316to332°C for these polymers.Based on these data,it is evident that the incorporation of linear or cyclohexane‐based diol repeating units changed the thermal properties of the PIC.展开更多
The master curves of a series of aliphatic polycarbonates （APCs） with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements. The plateau modulus and entanglemen...The master curves of a series of aliphatic polycarbonates （APCs） with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements. The plateau modulus and entanglement molecular weight were determined and cross-checked by different methods. Though having distinct difference in chemical structure of repeat units, both APCs and bisphenol-A polycarbonates have the similar entanglement weight and entanglement spacing. On the other side, the plateau modulus decreases with increasing the length of the side group of aliphatic polycarbonates with different side-chain lengths in the literature. The packing length model can explain the relationship between chain structure and entanglements.展开更多
Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as catalys...Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as catalyst.The aqueous solutions of thermo-responsive polycarbonates were investigated by rheological measurements.Steady-state shear measurements reveal that the polycarbonate solutions exhibit shear-thinning behavior and the hydrophilic content has a pronounced effect on the flow behavior of the polycarbonates aqueous solutions.The shear viscosity decreases with increasing poly(ethylene oxide)(PEO) composition.The increase of viscosity with increasing concentration is probably attributed to the formation of stronger network owing to interchain entanglement of PEO block at higher concentration.When the flow curves are fitted to the power law model,flow index is obtained to be less than 1,as exhibiting typical pesudoplastic fluid.The viscoelastic properties of the system also show close dependence on the composition of polycarbonates.Temperature sweep confirms that the multiblock polycarbonates exhibit thermo-responsive properties.For 7% aqueous solution of polycarbonate with composition ratio of EO to PO of 1/1,the sol-gel transition occurs at 37 ℃,which makes the system suitable as an injectable drug delivery system.展开更多
In this study,a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method,among which,progestin levonorgestrel(LNG)was used as a model drug.Photo-cross-linked aliphatic polyc...In this study,a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method,among which,progestin levonorgestrel(LNG)was used as a model drug.Photo-cross-linked aliphatic polycarbonates(APCs),namely,poly(trimethylene carbonate-co-2,2′-dimethyltrimethylene carbonate)[P(TMC-co-DTC)]elastomers,were used as the drug delivery matrix.The results obtained from the degradation experiments carried out in Sprague-Dawley(SD)rats showed that the cross-linked elastomer had the degradation characteristics of the surface erosion degradation mechanism,with no generation of acid degradation products,and excellent form-stability,which met the performance requirements of the matrix for a long-acting sustained-release delivery system.The in vitro cytotoxicity tests and histological and immunohistochemical evaluations showed good biocompatibility and biosafety of the elastomer matrix material and contraceptive implants.Subsequently,the implant formulations were screened by in vitro release experiments,and their release kinetics were explored.Finally,in the evaluation study of the in vivo anti-fertility effect,the implants exhibited excellent dimensional stability and were degraded by a surface erosion mechanism.LNG achieved a stable and sustained release in female SD rats,maintaining a long-acting contraceptive duration of up to 4 months.The contraceptive implants obtained in this study could be used to address the limitations of currently available formulations,which required secondary surgical removal and a single means of regulating drug release kinetics.Therefore,these implants could provide a new option for birth control needs and may be of significance in reducing the incidence of induced abortion and protecting female fertility.展开更多
CO2-based stereocomplexed polycarbonates derived from the intermolecularly interlocked interaction between the enantiopure polymers with the opposite configuration exhibit high crystallinity, excellent thermal and mec...CO2-based stereocomplexed polycarbonates derived from the intermolecularly interlocked interaction between the enantiopure polymers with the opposite configuration exhibit high crystallinity, excellent thermal and mechanical stabilities. Deep insights into the mechanism of stereocomplexation are of particular importance to the design and manufacture of new promising and sustainable polycarbonates with enhanced physicochemical properties. Our solid-state NMR experiments linking with DFT computations clearly reveal the specific chain-chain interactions in a typical stereocomplexed poly（4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0] octane carbonate）（PCXC）.13C CP/MAS NMR,1H DUMBO MAS NMR and 13C/1H relaxation-time measurements indicate that the formation of stereocomplex reduces the local mobilities of carbonyl, methine and methylene groups in each chain of PCXC significantly. Through a combination of two-dimensional 1H-13C HETCOR NMR and DFT calculation analysis, the cis-/trans-conformations and packing models of PCXC chains in the amorphous, enantionpure isotactic and stereocomplexed polycarbonates are identified. The splitting of 13C and 1H NMR chemical shifts of methine groups in the backbone carbon region demonstrates the ordered interlock interactions between the R-and S-chain in the stereocomplexed PCXC.展开更多
A new six-membered cyclic carbonate monomer, 5-allyloxytrimethylene carbonate （ATMC）, was synthesized starting from glycerol, and the corresponding polycarbonates, poly（5-allyloxytrimethylene carbonate）（PATMC） w...A new six-membered cyclic carbonate monomer, 5-allyloxytrimethylene carbonate （ATMC）, was synthesized starting from glycerol, and the corresponding polycarbonates, poly（5-allyloxytrimethylene carbonate）（PATMC） were further synthesized by ring-opening polymerization in bulk at 150℃ using stannous octanoate as an initiator. The structures of the monomer and the polymers were confirmed by IR, IH-NMR, 13C-NMR, and GPC analysis.展开更多
Amphiphilic block copolymers of poly（5-benzyloxy trimethylene carbonate） （PBTMC） and poly（ethylene glycol） （PEG） were synthesized through enzymatic polymerization using immobilized porcine pancreas lipase （I...Amphiphilic block copolymers of poly（5-benzyloxy trimethylene carbonate） （PBTMC） and poly（ethylene glycol） （PEG） were synthesized through enzymatic polymerization using immobilized porcine pancreas lipase （IPPL）. The obtained copolymers with different compositions were characterized by GPC and IH NMR. The copolymer composition was in agreement with the feed ratio. The molecular weight of the copolymers showed an increasing trend with the decrease of PEG contents. MiceUes of the copolymers were formed by dialysis procedure, and characterized by transmission electron microscopy （TEM）.展开更多
A series of transparent,intrinsically flame-retardant,and impact-resistant poly(carbonates-b-siloxanes)were synthesized by incorporating Schiff-base modified polysiloxanes(DMS-Schiff)and naphthalene-sulfonate units in...A series of transparent,intrinsically flame-retardant,and impact-resistant poly(carbonates-b-siloxanes)were synthesized by incorporating Schiff-base modified polysiloxanes(DMS-Schiff)and naphthalene-sulfonate units into the polycarbonate(PC)chain.In addition to high transparency,the resultant copolymers(SS-co-PC5,SS-co-PC9,SS-co-PC14,and SS-co-PC20)exhibited remarkable improvements in fire safety and mechanical performance.Compared to pure PC,these copolymers demonstrated significantly enhanced limiting oxygen index(LOI,up to 34.5%)and a UL-94 V-0 rating under a thickness of only 1.6 mm.The incorporation of the polysiloxane blocks not only improved flame retardancy but also enhanced the impact strength,with SS-co-PC9 showing a 48%increase in elongation at break and a 38%rise in impact toughness compared to pure PC.In addition,SS-co-PC9 presented high mechanical strength.The synergistic effects between the naphthalene-sulfonate and polysiloxane blocks,along with the well-controlled polysiloxane phase separation(sulfonate units enabled lower processing viscosity of copolymers),led to superior comprehensive performance.These findings provide a promising pathway to create high-performance copolycarbonates for real-world applications.展开更多
基金The authors are grateful for the financial support of the National Natural Science Foundation of China （No. 20104005）.
文摘Novel polycarbonates from 5-allyloxy-1, 3-dioxan-2-one （ATMC） with 5, 5-dimethyl- 1, 3-dioxan-2-one （DTC） were successfully synthesized for the first time using immobilized porcine pancreas lipase （IPPL） as catalyst. The resulting copolymers were characterized by IR, ^1H NMR, ^13C NMR and GPC. The molecular weight （Mn） of the copolymer with molar feed ratio of 10：90 （ATMC：DTC） was 9300 and the polydispersity was 1.31, while the Mn increased to 14300 and polydispersity of 1.25 with the feed ratio of 50：50. Moreover, the composition of the copolymers agreed well with the monomer feed.
基金supported by the National Key Projects for Fundamental Research and Development of China(2016YFB0600903)the National Natural Science Foundation of China(91434107,21506226,21476245)the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(QYZDY-SSW-JSC011)~~
文摘A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation process.The relationship between the anions of the ILs and the catalytic activities was investigated,and the readily‐prepared IL tetraethylammonium imidazolate(TEAI)was found to exhibit the highest catalytic activity.After optimizing the reaction conditions,a PIC with a weight‐average molecular weight(Mw)of25600g/mol was obtained,in conjunction with an isosorbide conversion of92%.As a means of modifying the molecular flexibility and thermal properties of the PIC,poly(aliphatic diol‐co‐isosorbide carbonate)s(PAIC)s were successfully synthesized,again using TEAI,and polymers with Mw values ranging from29000to112000g/mol were obtained.13C NMR analyses determined that the PAIC specimens had random microstructures,while differential scanning calorimetry demonstrated that each of the PAICs were amorphous and had glass transition temperatures ranging from50to115°C.Thermogravimetric analyses found Td‐5%values ranging from316to332°C for these polymers.Based on these data,it is evident that the incorporation of linear or cyclohexane‐based diol repeating units changed the thermal properties of the PIC.
基金financially supported by National Natural Science Foundation of China(No.20874109)National High Technology Research and Development Program of China(No.2009AA033601) and the Chinese Academy of Sciences
文摘The master curves of a series of aliphatic polycarbonates （APCs） with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements. The plateau modulus and entanglement molecular weight were determined and cross-checked by different methods. Though having distinct difference in chemical structure of repeat units, both APCs and bisphenol-A polycarbonates have the similar entanglement weight and entanglement spacing. On the other side, the plateau modulus decreases with increasing the length of the side group of aliphatic polycarbonates with different side-chain lengths in the literature. The packing length model can explain the relationship between chain structure and entanglements.
基金Projects(2006GG2203007) supported by the Scientific Research Project of Shandong Province,China
文摘Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as catalyst.The aqueous solutions of thermo-responsive polycarbonates were investigated by rheological measurements.Steady-state shear measurements reveal that the polycarbonate solutions exhibit shear-thinning behavior and the hydrophilic content has a pronounced effect on the flow behavior of the polycarbonates aqueous solutions.The shear viscosity decreases with increasing poly(ethylene oxide)(PEO) composition.The increase of viscosity with increasing concentration is probably attributed to the formation of stronger network owing to interchain entanglement of PEO block at higher concentration.When the flow curves are fitted to the power law model,flow index is obtained to be less than 1,as exhibiting typical pesudoplastic fluid.The viscoelastic properties of the system also show close dependence on the composition of polycarbonates.Temperature sweep confirms that the multiblock polycarbonates exhibit thermo-responsive properties.For 7% aqueous solution of polycarbonate with composition ratio of EO to PO of 1/1,the sol-gel transition occurs at 37 ℃,which makes the system suitable as an injectable drug delivery system.
基金sponsored by the Natural Science Foundation of Liaoning Province(Nos.2022-YGJC-69,2021-BS-110)the support program for excellent young scholars of China Medical University.
文摘In this study,a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method,among which,progestin levonorgestrel(LNG)was used as a model drug.Photo-cross-linked aliphatic polycarbonates(APCs),namely,poly(trimethylene carbonate-co-2,2′-dimethyltrimethylene carbonate)[P(TMC-co-DTC)]elastomers,were used as the drug delivery matrix.The results obtained from the degradation experiments carried out in Sprague-Dawley(SD)rats showed that the cross-linked elastomer had the degradation characteristics of the surface erosion degradation mechanism,with no generation of acid degradation products,and excellent form-stability,which met the performance requirements of the matrix for a long-acting sustained-release delivery system.The in vitro cytotoxicity tests and histological and immunohistochemical evaluations showed good biocompatibility and biosafety of the elastomer matrix material and contraceptive implants.Subsequently,the implant formulations were screened by in vitro release experiments,and their release kinetics were explored.Finally,in the evaluation study of the in vivo anti-fertility effect,the implants exhibited excellent dimensional stability and were degraded by a surface erosion mechanism.LNG achieved a stable and sustained release in female SD rats,maintaining a long-acting contraceptive duration of up to 4 months.The contraceptive implants obtained in this study could be used to address the limitations of currently available formulations,which required secondary surgical removal and a single means of regulating drug release kinetics.Therefore,these implants could provide a new option for birth control needs and may be of significance in reducing the incidence of induced abortion and protecting female fertility.
基金financial supports from the National Natural Science Foundation of China (Nos. 21373035, 21673027 and 21603022)the Fundamental Research Funds for the Central Universities in China (Nos. DUT16RC(3)002 and DUT17TD04)
文摘CO2-based stereocomplexed polycarbonates derived from the intermolecularly interlocked interaction between the enantiopure polymers with the opposite configuration exhibit high crystallinity, excellent thermal and mechanical stabilities. Deep insights into the mechanism of stereocomplexation are of particular importance to the design and manufacture of new promising and sustainable polycarbonates with enhanced physicochemical properties. Our solid-state NMR experiments linking with DFT computations clearly reveal the specific chain-chain interactions in a typical stereocomplexed poly（4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0] octane carbonate）（PCXC）.13C CP/MAS NMR,1H DUMBO MAS NMR and 13C/1H relaxation-time measurements indicate that the formation of stereocomplex reduces the local mobilities of carbonyl, methine and methylene groups in each chain of PCXC significantly. Through a combination of two-dimensional 1H-13C HETCOR NMR and DFT calculation analysis, the cis-/trans-conformations and packing models of PCXC chains in the amorphous, enantionpure isotactic and stereocomplexed polycarbonates are identified. The splitting of 13C and 1H NMR chemical shifts of methine groups in the backbone carbon region demonstrates the ordered interlock interactions between the R-and S-chain in the stereocomplexed PCXC.
基金support of the National Natural Science Foundation of China(Grant No.20104005)
文摘A new six-membered cyclic carbonate monomer, 5-allyloxytrimethylene carbonate （ATMC）, was synthesized starting from glycerol, and the corresponding polycarbonates, poly（5-allyloxytrimethylene carbonate）（PATMC） were further synthesized by ring-opening polymerization in bulk at 150℃ using stannous octanoate as an initiator. The structures of the monomer and the polymers were confirmed by IR, IH-NMR, 13C-NMR, and GPC analysis.
文摘Amphiphilic block copolymers of poly（5-benzyloxy trimethylene carbonate） （PBTMC） and poly（ethylene glycol） （PEG） were synthesized through enzymatic polymerization using immobilized porcine pancreas lipase （IPPL）. The obtained copolymers with different compositions were characterized by GPC and IH NMR. The copolymer composition was in agreement with the feed ratio. The molecular weight of the copolymers showed an increasing trend with the decrease of PEG contents. MiceUes of the copolymers were formed by dialysis procedure, and characterized by transmission electron microscopy （TEM）.
基金financially supported by the National Natural Science Foundation of China(Nos.52403117,52173083,51991355,and 52173082)the 2024 Ningbo Yongjiang Talent Programme,the Natural Science Foundation of Zhejiang Province(No.LY24E030007)the Australian Research Council(No.DE230100616).
文摘A series of transparent,intrinsically flame-retardant,and impact-resistant poly(carbonates-b-siloxanes)were synthesized by incorporating Schiff-base modified polysiloxanes(DMS-Schiff)and naphthalene-sulfonate units into the polycarbonate(PC)chain.In addition to high transparency,the resultant copolymers(SS-co-PC5,SS-co-PC9,SS-co-PC14,and SS-co-PC20)exhibited remarkable improvements in fire safety and mechanical performance.Compared to pure PC,these copolymers demonstrated significantly enhanced limiting oxygen index(LOI,up to 34.5%)and a UL-94 V-0 rating under a thickness of only 1.6 mm.The incorporation of the polysiloxane blocks not only improved flame retardancy but also enhanced the impact strength,with SS-co-PC9 showing a 48%increase in elongation at break and a 38%rise in impact toughness compared to pure PC.In addition,SS-co-PC9 presented high mechanical strength.The synergistic effects between the naphthalene-sulfonate and polysiloxane blocks,along with the well-controlled polysiloxane phase separation(sulfonate units enabled lower processing viscosity of copolymers),led to superior comprehensive performance.These findings provide a promising pathway to create high-performance copolycarbonates for real-world applications.
