13C spin-lattice relaxation times (T1) of a conjugated polymer MEH-PPV in polymer/ layered silicate nanocomposites together with the steady state fluorescence emission and transient fluorescence decay measurements hav...13C spin-lattice relaxation times (T1) of a conjugated polymer MEH-PPV in polymer/ layered silicate nanocomposites together with the steady state fluorescence emission and transient fluorescence decay measurements have been investigated. The T1 values of the conjugated carbons decrease dramatically according to the reduction of polymer concentration in the nano composites, while the fluorescence life times (τ) show a linear prolonging tendency. The results are explained from the point of view of molecular dynamics.展开更多
(a)NCA polymerization initiated by LiHMDS or other initiators in THF,initiator i)n-hexylamine,ii)HMDS,iii)bipyNi(COD);(b)LiHMDS-initiated open vessel polymerization of BLGNCA at 26 mg and 2 g scale;(c)GPC traces of po...(a)NCA polymerization initiated by LiHMDS or other initiators in THF,initiator i)n-hexylamine,ii)HMDS,iii)bipyNi(COD);(b)LiHMDS-initiated open vessel polymerization of BLGNCA at 26 mg and 2 g scale;(c)GPC traces of poly-BLG at variable DP;(d)Reaction rates of LiHMDS and hexylamine initiated BLGNCA polymerization in THF with NCA:initiator ratio of 100∶1 and initial NCA concentration at 0.2 mol/L;(e)CD spectra of poly-BLG at variable DP prepared from LiHMDS-initiated NCA polymerization.展开更多
A series of cyclic (arylene phosphonate) oligomers were prepared by reaction of phenylphosphonic dichloride (PPD) with various bisphenols under pseudo-high dilution conditions via interfacial polycondensation. The yie...A series of cyclic (arylene phosphonate) oligomers were prepared by reaction of phenylphosphonic dichloride (PPD) with various bisphenols under pseudo-high dilution conditions via interfacial polycondensation. The yield of cyclic (arylene phosphonate) oligomers is over 85% by using hexadecyltrimethylammoniun bromide as phase transfer catalyst (PTC) at 0 "C . The structures of the cyclic oligomers were confirmed by a combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and IR analysis. These cyclic oligomers undergo facile ring-opening polymerization in the melt by using potassium 4,4’-biphenoxide as the initiator to give linear polyphosphonate. Free-radical ring-opening polymerization of cyclic(arylene phosphonate) oligomers containing sulfur linkages was also performed in the melt using 2,2’-dithiobis(benzothiazole) (DTB) as the initiator at 270 °C and the resulting polymer had a Mw, of 8 × 103 with a molecular weight distribution of 4. Ring-opening copolymerization of these cyclic oligomers with cyclic carbonate oligomers was also achieved. The average molecular weight of the resulting copolymer is higher than the corresponding homopolymer and the thermal stability of the copolymer is better than the corresponding homopolymer.展开更多
Mesoporous silica(MS),3-aminopropyltriethoxysilane(APTES) modified mesoporous silica(AMS),bis(3- trimethoxysilylpropyl)amine modified mesoporous silica(BAMS) and APTES modified solid spherical silica(AS) were prepared...Mesoporous silica(MS),3-aminopropyltriethoxysilane(APTES) modified mesoporous silica(AMS),bis(3- trimethoxysilylpropyl)amine modified mesoporous silica(BAMS) and APTES modified solid spherical silica(AS) were prepared and used to immobilize metallocene catalysts for ethylene polymerization.Gel permeation chromatography results showed that polyethylenes(PEs) catalyzed by AMS(or BAMS) supported metallocene catalysts at the molar ratios of Al/Zr =100,300 and 500 were of bimodal molecular weight distribution(BMWD);while PEs catalyzed by the above catalysts at the molar ratios of Al/Zr≥800 were of monomodal molecular weight distribution(MMWD).However,MS(or AS) supported metallocene catalysts could only produce PEs with MMWD in spite of the molar ratio of Al/Zr.It was because that AMS(or BAMS) supported catalysts possessed two active sites for ethylene polymerization at low molar ratios of Al/Zr due to the combination effects of mesopore geometrical constraint and amino groups of the supports,which was confirmed by X-ray photoelectron spectroscopy.This brings forward a novel and easy method for the synthesis of polyolefin with BMWD.展开更多
A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The su...A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The surface property of the copolymer films was subsequently characterized. The contact angle measurements and energy dispersive analysis of X-ray (EDAX) show that the length and content of perfluoroalkyl side chains in the copolymers are crucial for the preparation of the film with low surface energy. At a given content of fluorinated monomers in the copolymers, the longer the perfluoroalkyl side chain, the larger the water contact angle of the copolymer films will be. On the other hand, the higher the content of fluorinated monomers, the lower the surface energy is. The water contact angle increases with the increase of the fluorinated monomer content and reaches a plateau at 3 wt% of fluorinated monomer content.展开更多
Compared to regular conjugated polymers,the random conjugated terpolymers are usually not beneficial to achieve highly efficient non-fullerene(NF)-based polymer solar cells(PSCs)due to their disordered chemical struct...Compared to regular conjugated polymers,the random conjugated terpolymers are usually not beneficial to achieve highly efficient non-fullerene(NF)-based polymer solar cells(PSCs)due to their disordered chemical structures.In this work,we report two random terpolymer donors(PBNB80 and PBNB50)by tuning the molar ratio of electron-accepting units of 1,3-di(thiophen-2-yl)naphtho[2,3-c]thiophene-4,9-dione(NTD)and 1,3-bis(4-chlorothiophen-2-yl)-4 H,8 H-benzo[1,2-c:4,5-c’]dithiophene-4,8-dione(ClBDD),at the same time,the parent polymers(PBNB100 and PBNB00)are also compared to study.These four polymer donors exhibit similar optical bandgaps and gradually deepen highest occupied molecular orbital levels.Importantly,aggregation and self-organization properties of the random terpolymer donors are optimized,which result in the better morphology and crystal coherence length after blending with NF acceptor of BO-4 Cl.Particularly,a PBNB80:BO-4 Cl blend forms an optimal nanoscale phase-separation morphology,thereby producing an outstanding power conversion efficiency of 16.0%,which is much higher than those(12.8%and 10.7%)of their parent binary polymer donor-based devices.This work demonstrates that rational using terpolymerization strategy to prepare random terpolymer is a very important method to achieve highly efficient NF-PSCs.展开更多
The possibility of mesoporous acid solid as a carrier for metallocene catalyst in ethylene polymerization and catalyst for polyethylene (PE) catalytic degradation was investigated. Here, HMCM-41 and A1MCM-41, and meso...The possibility of mesoporous acid solid as a carrier for metallocene catalyst in ethylene polymerization and catalyst for polyethylene (PE) catalytic degradation was investigated. Here, HMCM-41 and A1MCM-41, and mesoporous silicoaluminophosphate molecular sieves (SAPO1 and SAPO2) were synthesized and used as acid solid. Much more gases were produced during catalytic degradation in PE/acid solid mixtures via in situ polymerization than those via physical mixing. The particle size distribution results exhibited that the particle size of SAPO1 in the PE/SAPO1 mixture via in situ polymerization was about 1/14 times of that of the original SAPO1 or SAPO1-supported metallocene catalyst. This work shows a novel technology for chemical recycling of polyolefin.展开更多
An enantiopure helical coordination polymer AgPF6·(R)-3 as crystalline solid was synthesized by the self-assembly of chiral binaphthyl-based ligand(R)-6,6'-di[6-(2,2'-bipyridyl)]-2,2'-diethoxyl-1,1...An enantiopure helical coordination polymer AgPF6·(R)-3 as crystalline solid was synthesized by the self-assembly of chiral binaphthyl-based ligand(R)-6,6'-di[6-(2,2'-bipyridyl)]-2,2'-diethoxyl-1,1'-binaphthalene [(R)-3] and Ag+ ion.The single crystal structural analysis indicates that this polymer exhibits an infinite cylindric single-stranded M-helical structure with local Λ configuration at each tetrahedral metal center.However,the extended structure is dissociated into some oligomeric fragments in solution.The 1H NMR spectra of complex AgPF6·(R)-3 show that the ligand possesses a good C2 symmetry,and the chemical shifts of the protons depend on the concentration and temperature.In addition,there are rapid dynamic exchanges among some oligonuclear fragments in the solution of AgPF6·(R)-3.展开更多
The miscibility and structure ofA-B copolymer/C homopolymer blends with special interactions were studied by a Monte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, w...The miscibility and structure ofA-B copolymer/C homopolymer blends with special interactions were studied by a Monte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, whereas it was attractive between segment B and segment C. In order to study the effect of copolymer chain structure on the morphology and structure of A-B copolymer/C homopolymer blends, the alternating, random and block A-B copolymers were introduced into the blends, respectively. The simulation results indicated that the miscibility of A-B block copolymer/C homopolymer blends depended on the chain structure of the A-B copolymer. Compared with. alternating or random copolymer, the block copolymer, especially the diblock copolymer, could lead to a poor miscibility of A-B copolymer/C homopolymer blends.Moreover, for diblock A-B copolymer/C homopolymer blends, obvious self-organized core-shell structure was observed in the segment B composition region from 20% to 60%. However, if diblock copolymer composition in the blends is less than 40%, obvious self-organized core-shell structure could be formed in the B-segment component region from 10 to 90%.Furthermore, computer statistical analysis for the simulation results showed that the core sizes tended to increase continuously and their distribution became wider with decreasing B-segment component.展开更多
Chloro(5,10,15,20-tetraphenyl-porphyrinato)-aluminum/tetraethylammonium bromide(Et4NBr)in combination with bulky Lewis acid was used for the copolymerization of CO_2 and cyclohexene oxide(CHO).Bulky Lewis acid having ...Chloro(5,10,15,20-tetraphenyl-porphyrinato)-aluminum/tetraethylammonium bromide(Et4NBr)in combination with bulky Lewis acid was used for the copolymerization of CO_2 and cyclohexene oxide(CHO).Bulky Lewis acid having substituents at the ortho positions of the phenolate ligands,like methylaluminum bis(2,6-di-tert-butyl-4-methylphenolate), significantly shortened the induction period and raised the catalytic activity,the corresponding turnover frequency reached 44.9 h^(-1)in 9 h,which was 23.8% higher than...展开更多
Films obtained via drying a polymeric latex dispersion are normally colloidal crystalline where latex particles are packed into a face centered cubic (fcc) structure.Different from conventional atomic crystallites or ...Films obtained via drying a polymeric latex dispersion are normally colloidal crystalline where latex particles are packed into a face centered cubic (fcc) structure.Different from conventional atomic crystallites or hard sphere colloidal crystallites,the crystalline structure of these films is normally deformable due to the low glass transition temperature of the latex particles.Upon tensile deformation,depending on the drawing direction with respect to the normal of specific crystallographic plane,one ...展开更多
Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-san...Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.展开更多
In this paper,melt blends of poly(propylene carbonate)(PPC)with poly(butylene succinate)(PBS)were characterized by dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),tensile testing,wide-angle X-r...In this paper,melt blends of poly(propylene carbonate)(PPC)with poly(butylene succinate)(PBS)were characterized by dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),tensile testing,wide-angle X-ray diffraction(WAXD),polarized optical microscopy and thermogravimetric analysis(TGA).The results indicated that the glass transition temperature of PPC in the 90/10 PPC/PBS blend was decreased by about 11K comparing with that of pure PPC.The presence of 10% PBS was partially miscible with PPC.The 90/10 PPC/PBS blend had better impact ==========and tensile strength than those of the other PPC/PBS blends.The glass transition temperature of PPC in the 80/20,70/30,and 60/40 PPC/PBS blends was improved by about 4.9 K,4.2 K,and 13 K comparing with that of pure PPC,respectively;which indicated the immiscibility between PPC and PBS.The DSC results indicated that the crystallization of PBS became more difficult when the PPC content increased.The matrix of PPC hindered the crystallization process of PBS.While the content of PBS was above 20%,significant crystallization-induced phase separation was observed by polarized optical microscopy. It was found from the WAXD analysis that the crystal structure of PBS did not change,and the degree of crystallinity increased with increasing PBS content in the PPC/PBS blends.展开更多
The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates to synthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane por...The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates to synthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and the layer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm the methodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results.展开更多
Enhanced permeation and retention(EPR) targeting effect of rhodamine B labeled PEG-b-P(LA-co-DHP) [PEG:poly(ethylene glycol);LA:L-lactide;DHP:2,2-dihydroxylmethyl-propylene carbonate] micelles(RhB-micelles) was observ...Enhanced permeation and retention(EPR) targeting effect of rhodamine B labeled PEG-b-P(LA-co-DHP) [PEG:poly(ethylene glycol);LA:L-lactide;DHP:2,2-dihydroxylmethyl-propylene carbonate] micelles(RhB-micelles) was observed in H22 liver cancer bearing mice.The RhB-micelles were prepared by conjugating rhodamine B with the DHP units of amphiphilic block copolymer PEG-b-P(LA-co-DHP) followed by subsequent self-assembling of the conjugate.The parent copolymer PEG-b-P(LA-co-DHP) was synthesized by ring-opening copolymerization of LA and DHP with PEG as macroinitiator and diethyl zinc(ZnEt2) as catalyst.The micelles have a spherical shape and the average diameter is ca.50 nm by TEM(transmission electron microscope) or 80 nm by DLS(dynamic light scattering).Their in vitro cell uptake experiment by CLSM(confocal laser scanning microscopy) and flow cytometry showed preferential internalization of micelles by MCF-7 human breast cancer cells to free RhB.The in vivo tests by live animal imaging and ex vivo excised organ imaging showed that after vena tail injection,free RhB molecules were distributed in the whole body through the circulation system and then gradually metabolized and excreted and there was no preferential partition in tumor bed from the beginning to the end.But the RhB-micelles were preferentially distributed to the tumor bed so that their concentration(fluorescent intensity) in tumor bed got the level of the liver at a certain time point between 1 and 6 h and reached a maximum relative intensity at around 12 h,indicating an obvious EPR effect of RhB-micelles in H22 liver cancer.展开更多
Two kinds of paclitaxel(PTX) conjugate micelles,of which one contained 25%(mass fraction) PTX [M(PTX)] and the other contained 22.5%(mass fraction) of PTX and 1.4%(mass fraction) of folate(FA)[FA-M(PTX)],were prepared...Two kinds of paclitaxel(PTX) conjugate micelles,of which one contained 25%(mass fraction) PTX [M(PTX)] and the other contained 22.5%(mass fraction) of PTX and 1.4%(mass fraction) of folate(FA)[FA-M(PTX)],were prepared for cell apoptosis and anti-tumor activity evaluation on U14 cervical cancer mouse models in comparison with 0.9%(mass fraction) saline(control) and equivalent Taxol.Seven days after tail intravenous injection of the drugs,the mice were sacrificed to measure the tumor masses.The average tumor masses were 4.26,2.89,2.63,and 2.17 g for the control,Taxol,M(PTX) and FA-M(PTX) groups,respectively.The inhibition rates of tumor growth calculated for the three drug groups were 32%,38% and 49%,respectively.Flow cytometry(FC) analysis and terminal deoxynucleotidyl transferase(TdT)-mediated deoxyuridine triphosphate(dUTP) nick end labeling(TUNEL) assay were conducted on the cancer tissues.The cell apoptosis rates based on the FC data and the TUNEL data were 20%,31%,37%,42%,and 10%,22%,26%,34%,respectively,both showing statistically significant differences(P<0.05) between three drug groups and the control group,and between the FA-M(PTX) group and the other two drug groups.In conclusion,the composite FA-M(PTX) micelles can be used for U14 cervical cancer treatment.展开更多
A degradable poly(lactic-co-glycolic acid, LA:GA=80:20)(PLGA) urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyd...A degradable poly(lactic-co-glycolic acid, LA:GA=80:20)(PLGA) urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyde. The structure and properties of the crosslinked scaffolds were investigated by the mechanical property testing, scanning electron microscopy(SEM), degradability test in vitro and 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-diphenytetrazo- liumromide(MTT). The results show that the scaffold has the nano-structure. The pore size and the porosity are suitable for cell seeding, growth and extracellular matrix production. Although influenced by the crosslinking slightly, the pore size and the porosity could still support cell proliferation and tissuse formation. The mechanical properties are remarkably increased by the crosslinking of glutaraldehyde, and it could meet the demands of a urethral stent. The scaffold could completely collapse within 70 d. The results of the biocompatibility test show that the PLGA scaffold had no cytotoxicity.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.20023003).
文摘13C spin-lattice relaxation times (T1) of a conjugated polymer MEH-PPV in polymer/ layered silicate nanocomposites together with the steady state fluorescence emission and transient fluorescence decay measurements have been investigated. The T1 values of the conjugated carbons decrease dramatically according to the reduction of polymer concentration in the nano composites, while the fluorescence life times (τ) show a linear prolonging tendency. The results are explained from the point of view of molecular dynamics.
文摘(a)NCA polymerization initiated by LiHMDS or other initiators in THF,initiator i)n-hexylamine,ii)HMDS,iii)bipyNi(COD);(b)LiHMDS-initiated open vessel polymerization of BLGNCA at 26 mg and 2 g scale;(c)GPC traces of poly-BLG at variable DP;(d)Reaction rates of LiHMDS and hexylamine initiated BLGNCA polymerization in THF with NCA:initiator ratio of 100∶1 and initial NCA concentration at 0.2 mol/L;(e)CD spectra of poly-BLG at variable DP prepared from LiHMDS-initiated NCA polymerization.
基金This project was supported by the National Natural Science Foundation of China (No. 20084001).
文摘A series of cyclic (arylene phosphonate) oligomers were prepared by reaction of phenylphosphonic dichloride (PPD) with various bisphenols under pseudo-high dilution conditions via interfacial polycondensation. The yield of cyclic (arylene phosphonate) oligomers is over 85% by using hexadecyltrimethylammoniun bromide as phase transfer catalyst (PTC) at 0 "C . The structures of the cyclic oligomers were confirmed by a combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and IR analysis. These cyclic oligomers undergo facile ring-opening polymerization in the melt by using potassium 4,4’-biphenoxide as the initiator to give linear polyphosphonate. Free-radical ring-opening polymerization of cyclic(arylene phosphonate) oligomers containing sulfur linkages was also performed in the melt using 2,2’-dithiobis(benzothiazole) (DTB) as the initiator at 270 °C and the resulting polymer had a Mw, of 8 × 103 with a molecular weight distribution of 4. Ring-opening copolymerization of these cyclic oligomers with cyclic carbonate oligomers was also achieved. The average molecular weight of the resulting copolymer is higher than the corresponding homopolymer and the thermal stability of the copolymer is better than the corresponding homopolymer.
基金supported by the National Natural Science Foundation of China(Nos.50525311,20734006 and 50621302)
文摘Mesoporous silica(MS),3-aminopropyltriethoxysilane(APTES) modified mesoporous silica(AMS),bis(3- trimethoxysilylpropyl)amine modified mesoporous silica(BAMS) and APTES modified solid spherical silica(AS) were prepared and used to immobilize metallocene catalysts for ethylene polymerization.Gel permeation chromatography results showed that polyethylenes(PEs) catalyzed by AMS(or BAMS) supported metallocene catalysts at the molar ratios of Al/Zr =100,300 and 500 were of bimodal molecular weight distribution(BMWD);while PEs catalyzed by the above catalysts at the molar ratios of Al/Zr≥800 were of monomodal molecular weight distribution(MMWD).However,MS(or AS) supported metallocene catalysts could only produce PEs with MMWD in spite of the molar ratio of Al/Zr.It was because that AMS(or BAMS) supported catalysts possessed two active sites for ethylene polymerization at low molar ratios of Al/Zr due to the combination effects of mesopore geometrical constraint and amino groups of the supports,which was confirmed by X-ray photoelectron spectroscopy.This brings forward a novel and easy method for the synthesis of polyolefin with BMWD.
基金This work was partly supported by the National Natural Science Foundation of China (No. 50273008)Qingdao Municipal Science and Technology Commission.
文摘A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The surface property of the copolymer films was subsequently characterized. The contact angle measurements and energy dispersive analysis of X-ray (EDAX) show that the length and content of perfluoroalkyl side chains in the copolymers are crucial for the preparation of the film with low surface energy. At a given content of fluorinated monomers in the copolymers, the longer the perfluoroalkyl side chain, the larger the water contact angle of the copolymer films will be. On the other hand, the higher the content of fluorinated monomers, the lower the surface energy is. The water contact angle increases with the increase of the fluorinated monomer content and reaches a plateau at 3 wt% of fluorinated monomer content.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.51703228,51673201,21835006)Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-201903)。
文摘Compared to regular conjugated polymers,the random conjugated terpolymers are usually not beneficial to achieve highly efficient non-fullerene(NF)-based polymer solar cells(PSCs)due to their disordered chemical structures.In this work,we report two random terpolymer donors(PBNB80 and PBNB50)by tuning the molar ratio of electron-accepting units of 1,3-di(thiophen-2-yl)naphtho[2,3-c]thiophene-4,9-dione(NTD)and 1,3-bis(4-chlorothiophen-2-yl)-4 H,8 H-benzo[1,2-c:4,5-c’]dithiophene-4,8-dione(ClBDD),at the same time,the parent polymers(PBNB100 and PBNB00)are also compared to study.These four polymer donors exhibit similar optical bandgaps and gradually deepen highest occupied molecular orbital levels.Importantly,aggregation and self-organization properties of the random terpolymer donors are optimized,which result in the better morphology and crystal coherence length after blending with NF acceptor of BO-4 Cl.Particularly,a PBNB80:BO-4 Cl blend forms an optimal nanoscale phase-separation morphology,thereby producing an outstanding power conversion efficiency of 16.0%,which is much higher than those(12.8%and 10.7%)of their parent binary polymer donor-based devices.This work demonstrates that rational using terpolymerization strategy to prepare random terpolymer is a very important method to achieve highly efficient NF-PSCs.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51325303, 51273193 and 21334006, and the National Basic Research Program of China under Grant No 2014CB643504.
基金the support of the National Natural Science Foundation of China （No. 20174039） the Ministry of Science and Technology of China （No. 2005CB623800）.
文摘The possibility of mesoporous acid solid as a carrier for metallocene catalyst in ethylene polymerization and catalyst for polyethylene (PE) catalytic degradation was investigated. Here, HMCM-41 and A1MCM-41, and mesoporous silicoaluminophosphate molecular sieves (SAPO1 and SAPO2) were synthesized and used as acid solid. Much more gases were produced during catalytic degradation in PE/acid solid mixtures via in situ polymerization than those via physical mixing. The particle size distribution results exhibited that the particle size of SAPO1 in the PE/SAPO1 mixture via in situ polymerization was about 1/14 times of that of the original SAPO1 or SAPO1-supported metallocene catalyst. This work shows a novel technology for chemical recycling of polyolefin.
基金Supported by the National Natural Science Foundation of China(No.20502024)
文摘An enantiopure helical coordination polymer AgPF6·(R)-3 as crystalline solid was synthesized by the self-assembly of chiral binaphthyl-based ligand(R)-6,6'-di[6-(2,2'-bipyridyl)]-2,2'-diethoxyl-1,1'-binaphthalene [(R)-3] and Ag+ ion.The single crystal structural analysis indicates that this polymer exhibits an infinite cylindric single-stranded M-helical structure with local Λ configuration at each tetrahedral metal center.However,the extended structure is dissociated into some oligomeric fragments in solution.The 1H NMR spectra of complex AgPF6·(R)-3 show that the ligand possesses a good C2 symmetry,and the chemical shifts of the protons depend on the concentration and temperature.In addition,there are rapid dynamic exchanges among some oligonuclear fragments in the solution of AgPF6·(R)-3.
基金This work was supported by the National Natural Science Foundation of China (20023003, 50027001, 29704008, 20074037, 50073023 and 50290090) and subsidized by the Special Funds for Major Basic Research projects (G1999064800) and the Special Pre-Funds for
文摘The miscibility and structure ofA-B copolymer/C homopolymer blends with special interactions were studied by a Monte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, whereas it was attractive between segment B and segment C. In order to study the effect of copolymer chain structure on the morphology and structure of A-B copolymer/C homopolymer blends, the alternating, random and block A-B copolymers were introduced into the blends, respectively. The simulation results indicated that the miscibility of A-B block copolymer/C homopolymer blends depended on the chain structure of the A-B copolymer. Compared with. alternating or random copolymer, the block copolymer, especially the diblock copolymer, could lead to a poor miscibility of A-B copolymer/C homopolymer blends.Moreover, for diblock A-B copolymer/C homopolymer blends, obvious self-organized core-shell structure was observed in the segment B composition region from 20% to 60%. However, if diblock copolymer composition in the blends is less than 40%, obvious self-organized core-shell structure could be formed in the B-segment component region from 10 to 90%.Furthermore, computer statistical analysis for the simulation results showed that the core sizes tended to increase continuously and their distribution became wider with decreasing B-segment component.
基金The work was financially supported by the National Natural Science Foundation of China(No.20634040).
文摘Chloro(5,10,15,20-tetraphenyl-porphyrinato)-aluminum/tetraethylammonium bromide(Et4NBr)in combination with bulky Lewis acid was used for the copolymerization of CO_2 and cyclohexene oxide(CHO).Bulky Lewis acid having substituents at the ortho positions of the phenolate ligands,like methylaluminum bis(2,6-di-tert-butyl-4-methylphenolate), significantly shortened the induction period and raised the catalytic activity,the corresponding turnover frequency reached 44.9 h^(-1)in 9 h,which was 23.8% higher than...
基金supported by the"Hundred Talents Project"of the Chinese Academy of Sciences,the National Basic Research Program of China (No.2005CB623800)National Science Foundation of China (No.50621302)HASYLAB projectⅡ-20052011.
文摘Films obtained via drying a polymeric latex dispersion are normally colloidal crystalline where latex particles are packed into a face centered cubic (fcc) structure.Different from conventional atomic crystallites or hard sphere colloidal crystallites,the crystalline structure of these films is normally deformable due to the low glass transition temperature of the latex particles.Upon tensile deformation,depending on the drawing direction with respect to the normal of specific crystallographic plane,one ...
基金financially supported by the open research fund program of Science and Technology on Aerospace Chemical Power Laboratory (No. STACPL120221B03)the National Natural Science Foundation of China (Nos. s22175059,52073275 and U21A20279)。
文摘Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.
基金This work was supported by the National Natural Science Foundation of China(Nos.270274049 and 220374051).
文摘In this paper,melt blends of poly(propylene carbonate)(PPC)with poly(butylene succinate)(PBS)were characterized by dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),tensile testing,wide-angle X-ray diffraction(WAXD),polarized optical microscopy and thermogravimetric analysis(TGA).The results indicated that the glass transition temperature of PPC in the 90/10 PPC/PBS blend was decreased by about 11K comparing with that of pure PPC.The presence of 10% PBS was partially miscible with PPC.The 90/10 PPC/PBS blend had better impact ==========and tensile strength than those of the other PPC/PBS blends.The glass transition temperature of PPC in the 80/20,70/30,and 60/40 PPC/PBS blends was improved by about 4.9 K,4.2 K,and 13 K comparing with that of pure PPC,respectively;which indicated the immiscibility between PPC and PBS.The DSC results indicated that the crystallization of PBS became more difficult when the PPC content increased.The matrix of PPC hindered the crystallization process of PBS.While the content of PBS was above 20%,significant crystallization-induced phase separation was observed by polarized optical microscopy. It was found from the WAXD analysis that the crystal structure of PBS did not change,and the degree of crystallinity increased with increasing PBS content in the PPC/PBS blends.
基金This work was supported by the National Natural Science Foundation of China (No. 20023003 and 20128004).
文摘The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates to synthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and the layer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm the methodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results.
基金Supported by the National Basic Research Program of China(No.2009CB930102)the National High Technology Research and Development Program of China(No.2007AA03Z535)+3 种基金the National Natural Science Foundation of China(No.21004062)the China-Japan-Korea Foresight Program(No.20621140369)"100 Talents Program" of the Chinese Academy of Sciences(No.KGCX2- YW-802) the Project of Jilin Provincial Science & Technology Department,China(No.200705110)
文摘Enhanced permeation and retention(EPR) targeting effect of rhodamine B labeled PEG-b-P(LA-co-DHP) [PEG:poly(ethylene glycol);LA:L-lactide;DHP:2,2-dihydroxylmethyl-propylene carbonate] micelles(RhB-micelles) was observed in H22 liver cancer bearing mice.The RhB-micelles were prepared by conjugating rhodamine B with the DHP units of amphiphilic block copolymer PEG-b-P(LA-co-DHP) followed by subsequent self-assembling of the conjugate.The parent copolymer PEG-b-P(LA-co-DHP) was synthesized by ring-opening copolymerization of LA and DHP with PEG as macroinitiator and diethyl zinc(ZnEt2) as catalyst.The micelles have a spherical shape and the average diameter is ca.50 nm by TEM(transmission electron microscope) or 80 nm by DLS(dynamic light scattering).Their in vitro cell uptake experiment by CLSM(confocal laser scanning microscopy) and flow cytometry showed preferential internalization of micelles by MCF-7 human breast cancer cells to free RhB.The in vivo tests by live animal imaging and ex vivo excised organ imaging showed that after vena tail injection,free RhB molecules were distributed in the whole body through the circulation system and then gradually metabolized and excreted and there was no preferential partition in tumor bed from the beginning to the end.But the RhB-micelles were preferentially distributed to the tumor bed so that their concentration(fluorescent intensity) in tumor bed got the level of the liver at a certain time point between 1 and 6 h and reached a maximum relative intensity at around 12 h,indicating an obvious EPR effect of RhB-micelles in H22 liver cancer.
基金Supported by the National Natural Science Foundation of China(Nos.20674084,21004062,51103148)the National Basic Research Program of China(No.2009CB930102)the National High-Tech Research and Development Program of China(No.2007AA03Z535)
文摘Two kinds of paclitaxel(PTX) conjugate micelles,of which one contained 25%(mass fraction) PTX [M(PTX)] and the other contained 22.5%(mass fraction) of PTX and 1.4%(mass fraction) of folate(FA)[FA-M(PTX)],were prepared for cell apoptosis and anti-tumor activity evaluation on U14 cervical cancer mouse models in comparison with 0.9%(mass fraction) saline(control) and equivalent Taxol.Seven days after tail intravenous injection of the drugs,the mice were sacrificed to measure the tumor masses.The average tumor masses were 4.26,2.89,2.63,and 2.17 g for the control,Taxol,M(PTX) and FA-M(PTX) groups,respectively.The inhibition rates of tumor growth calculated for the three drug groups were 32%,38% and 49%,respectively.Flow cytometry(FC) analysis and terminal deoxynucleotidyl transferase(TdT)-mediated deoxyuridine triphosphate(dUTP) nick end labeling(TUNEL) assay were conducted on the cancer tissues.The cell apoptosis rates based on the FC data and the TUNEL data were 20%,31%,37%,42%,and 10%,22%,26%,34%,respectively,both showing statistically significant differences(P<0.05) between three drug groups and the control group,and between the FA-M(PTX) group and the other two drug groups.In conclusion,the composite FA-M(PTX) micelles can be used for U14 cervical cancer treatment.
基金supported by NSFC (29774036200174048) and National 863 Project (NO. 2001AA334060) aswell as SKLPPC Foundation Joint Laboratory of Polymer Sciences & Materials
基金Supported by the National Natural Science Foundation of China(No. 50973043)
文摘A degradable poly(lactic-co-glycolic acid, LA:GA=80:20)(PLGA) urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyde. The structure and properties of the crosslinked scaffolds were investigated by the mechanical property testing, scanning electron microscopy(SEM), degradability test in vitro and 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-diphenytetrazo- liumromide(MTT). The results show that the scaffold has the nano-structure. The pore size and the porosity are suitable for cell seeding, growth and extracellular matrix production. Although influenced by the crosslinking slightly, the pore size and the porosity could still support cell proliferation and tissuse formation. The mechanical properties are remarkably increased by the crosslinking of glutaraldehyde, and it could meet the demands of a urethral stent. The scaffold could completely collapse within 70 d. The results of the biocompatibility test show that the PLGA scaffold had no cytotoxicity.
