Solid dispersions of nifedipine(NDP), a poorly water-soluble drug, and amino methacrylate copolymer(AMCP) with aid of adsorbent, that is, fumed silica, talcum, calcium carbonate,titanium dioxide, and mesoporous silica...Solid dispersions of nifedipine(NDP), a poorly water-soluble drug, and amino methacrylate copolymer(AMCP) with aid of adsorbent, that is, fumed silica, talcum, calcium carbonate,titanium dioxide, and mesoporous silica from rice husks(SRH), were prepared by solvent method. The physicochemical properties of solid dispersions, compared to their physical mixtures, were determined using powder X-ray diffractometry(PXRD) and differential scanning calorimetry(DSC). The surface morphology of the prepared solid dispersions was examined by scanning electron microscopy(SEM). The dissolution of NDP from solid dispersions was compared to NDP powders. The effect of adsorbent type on NDP dissolution was also examined. The dissolution of NDP increased with the ratio of NDP:AMCP:adsorbent of 1:4:1 when compared to the other formulations. As indicated from PXRD patterns, DSC thermograms and SEM images, NDP was molecularly dispersed within polymer carrier or in an amorphous form, which confirmed the better dissolution of solid dispersions. Solid dispersions containing SRH provided the highest NDP dissolution, due to a porous nature of SRH, allowing dissolved drug to fill in the pores and consequently dissolve in the medium.The results suggested that solid dispersions containing adsorbents(SRH in particular) demonstrated improved dissolution of poorly water-soluble drug when compared to NDP powder.展开更多
The main objective of the present study is to develop a selfmicellizing solid dispersion(SMSD)system of cyclosporine A(CsA)using an amphiphilic copolymer,poly[MPC-co-BMA](pMB)to improve the biopharmaceutical propertie...The main objective of the present study is to develop a selfmicellizing solid dispersion(SMSD)system of cyclosporine A(CsA)using an amphiphilic copolymer,poly[MPC-co-BMA](pMB)to improve the biopharmaceutical properties of CsA(Fig.1A).Unlike conventional carrier compounds,pMB would perform the bifunctional ability as both polymeric carrier of solid dispersion system and solubilizer derived from a high micellizing property,which could be considered beneficial for the production of highly water soluble formulation of poorly water soluble compound[1].Improvement in the aqueous solubility has been believed to be a key consideration for acquiring potent pharmacological effects of BCS class II drug like CsA.展开更多
A stable silica sol with 3-5 nm in diameter, which can form homogeneous film without crack, was prepared and characterized. Then, the inorganic-organic hybrid aqueous dispersion composed of such a silica sol and an em...A stable silica sol with 3-5 nm in diameter, which can form homogeneous film without crack, was prepared and characterized. Then, the inorganic-organic hybrid aqueous dispersion composed of such a silica sol and an emulsion of styrene （St） and acrylate （Ac） copolymer was prepared and the hybrid effect between the silica sol and poly（St-co-Ac） was observed by Fourier transform infra-red （FT-IR） spectroscope. The toughness of the film prepared by this kind of hybrid aqueous dispersion was excellent, as it was enhanced appreciably by commixing with a small amount of poly（St-co-Ac） emulsion. Some amino-polysiloxane modified hybrid aqueous dispersions were also prepared and the properties of the modified dispersions and their films were investigated. The experimental results showed that the film prepared with such an amino-polysiloxane modified hybrid dispersion exhibited excellent hydrophobicity and low surface energy after heat treatment for 1.5 h, during which the formation of the graft copolymer was observed. The surface energy of this film decreases as a result of the enrichment of siloxane segments on the film surface.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
Here,we demonstrate the use of branched macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agents in RAFT dispersion polymerization,to access branched block copolymers as well as well-defined...Here,we demonstrate the use of branched macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agents in RAFT dispersion polymerization,to access branched block copolymers as well as well-defined branched block copolymer assemblies.Two types of branched macro-RAFT agents were first synthesized by using either a monofunctional chain transfer monomer or a difunctional chain transfer monomer in RAFT polymerization,and subsequently utilized in RAFT dispersion polymerization.It was found that only branched macro-RAFT agents synthesized from the difunctional chain transfer monomer could lead to colloidally stable assemblies with well-defined morphologies.Reaction conditions including monomer concentration,degree of polymerization (DP) of the core-forming block,and DP of the solvophilic segment on morphologies of branched block copolymer assemblies were investigated in detail.Size exclusion chromatography (SEC) analysis further confirmed the successful formation of branched block copolymers by using branched macro-RAFT agents.This work on the synthesis of branched block copolymer assemblies by RAFT dispersion polymerization offers new opportunities for the rational design of polymer assemblies with well-defined structures.展开更多
A novel multifunctional macromolecular organolithium initiator （PD-Sn-（RLi）3） was prepared via living anionic polymerization and used for the synthesis of miktoarm star copolymers in cyclohexane. The average molec...A novel multifunctional macromolecular organolithium initiator （PD-Sn-（RLi）3） was prepared via living anionic polymerization and used for the synthesis of miktoarm star copolymers in cyclohexane. The average molecular weight, polydispersity index, microstructure and unit composition of the miktoarm star copolymers were characterized with GPC and 1H-NMR. Performances of the miktoarm star styrene-butadiene rubbers were investigated in comparison with those of the blend rubbers such as the tin-coupled star-shaped random copolymers of styrene-butadiene rubber（S-SBR）/natural rubber （NR） blend rubber and S-SBR/Cis-1, 4-polybutadiene rubber （Cis-BR） blend rubber.展开更多
A series of new-type nanometer TiO2 modified polyacrylic copolymer sizing agent were synthesized from acrylic acid, ethyl acrylate, nanometer TiO2, oleic acid etc. by orthogonal design method. Results of the studies s...A series of new-type nanometer TiO2 modified polyacrylic copolymer sizing agent were synthesized from acrylic acid, ethyl acrylate, nanometer TiO2, oleic acid etc. by orthogonal design method. Results of the studies show that the synthetic method used in this paper was a new way and had never been found in the synthesis of acrylate sizing agent, and that the properties of those new-type size-agent were be improved, which had potential for substituting PVA (polyvinyl alcohol) sizing agent. The technology for solving the problem of nano-scale powder agglomeration and dispersion were also studied. The transmission electron microscope (TEM) observation showed that nano-TiO2had good dispersion and stability in aqueous solution and in sizing agent solution.展开更多
The purpose of this study was to investigate the change in the physical and mechanical properties of styrene-butadiene copolymer(SB)dispersion-modified calcium sulfoaluminate(CSA)cement mortar as it aged from 28 to 36...The purpose of this study was to investigate the change in the physical and mechanical properties of styrene-butadiene copolymer(SB)dispersion-modified calcium sulfoaluminate(CSA)cement mortar as it aged from 28 to 360 d,and cured at different temperatures and relative humidities.The results show that the mechanical properties of reference mortar(RM)of CSA cement,including its flexural,compressive,and tensile bond strength,showed a reduction after a certain time,but its water capillary absorption was hardly affected by age.When SB dispersion was added,there was no reduction in mechanical strength.The amount of SB added did matter.Addition of 5% SB had a negative effect on most properties compared with RM,except for tensile bond strength.However,the properties of SB-modified mortar(SBMM)were enhanced significantly as the amount of SB was increased from 5% to 20%.Temperature change had different effects on the properties of RM and SBMM.High temperature was beneficial to early flexural and compressive strength development of RM,but caused serious strength reduction at later stages.High temperature enhanced the development of tensile bond strength of RM.Increasing temperature enhanced properties of SBMM,including flexural,compressive,and tensile bond strength.Higher relative humidity improved all measured properties of all mortars.Scanning electron microscope(SEM)observations of the morphology of RM and SBMM at 360 d cured under different conditions accounted well for the changes in mechanical properties.展开更多
We reported an approach to reconstruct the complex phase morphology of impact polypropylene copolymer （IPC） with core-shell dispersed particles and to optimize its toughness in approximate shear condition. The molte...We reported an approach to reconstruct the complex phase morphology of impact polypropylene copolymer （IPC） with core-shell dispersed particles and to optimize its toughness in approximate shear condition. The molten-state annealing results indicate that the phase structure with core-shell dispersed particles is unstable and could be completely destroyed by static annealing, resulting in the degradation of impact strength. By using a co-rotating twin screw extruder, we found that the dispersed particle with core-shell structure could be rebuilt in appropriate condition with the recovery of excellent impact strength due to both the huge interfacial tension during solidification and the great difference in viscosity of components. Results reveal that almost all the extruded IPCs show the impact strength 60%-90% higher than that of annealed IPCs at room temperature. And the twice-extruded IPC shows the highest impact strength, 446% higher than that of IPC annealed for 30 min. As for low temperature tests, the impact strength of extruded IPCs also increases by 33%-58%. According to adjusting the processing conditions including extrusion speed, extrusion frequency and temperature, an optimization of toughness was well established.展开更多
文摘Solid dispersions of nifedipine(NDP), a poorly water-soluble drug, and amino methacrylate copolymer(AMCP) with aid of adsorbent, that is, fumed silica, talcum, calcium carbonate,titanium dioxide, and mesoporous silica from rice husks(SRH), were prepared by solvent method. The physicochemical properties of solid dispersions, compared to their physical mixtures, were determined using powder X-ray diffractometry(PXRD) and differential scanning calorimetry(DSC). The surface morphology of the prepared solid dispersions was examined by scanning electron microscopy(SEM). The dissolution of NDP from solid dispersions was compared to NDP powders. The effect of adsorbent type on NDP dissolution was also examined. The dissolution of NDP increased with the ratio of NDP:AMCP:adsorbent of 1:4:1 when compared to the other formulations. As indicated from PXRD patterns, DSC thermograms and SEM images, NDP was molecularly dispersed within polymer carrier or in an amorphous form, which confirmed the better dissolution of solid dispersions. Solid dispersions containing SRH provided the highest NDP dissolution, due to a porous nature of SRH, allowing dissolved drug to fill in the pores and consequently dissolve in the medium.The results suggested that solid dispersions containing adsorbents(SRH in particular) demonstrated improved dissolution of poorly water-soluble drug when compared to NDP powder.
文摘The main objective of the present study is to develop a selfmicellizing solid dispersion(SMSD)system of cyclosporine A(CsA)using an amphiphilic copolymer,poly[MPC-co-BMA](pMB)to improve the biopharmaceutical properties of CsA(Fig.1A).Unlike conventional carrier compounds,pMB would perform the bifunctional ability as both polymeric carrier of solid dispersion system and solubilizer derived from a high micellizing property,which could be considered beneficial for the production of highly water soluble formulation of poorly water soluble compound[1].Improvement in the aqueous solubility has been believed to be a key consideration for acquiring potent pharmacological effects of BCS class II drug like CsA.
基金Supported by Science and Technology Commission of Shanghai Municipality (No. 0212nm008).
文摘A stable silica sol with 3-5 nm in diameter, which can form homogeneous film without crack, was prepared and characterized. Then, the inorganic-organic hybrid aqueous dispersion composed of such a silica sol and an emulsion of styrene （St） and acrylate （Ac） copolymer was prepared and the hybrid effect between the silica sol and poly（St-co-Ac） was observed by Fourier transform infra-red （FT-IR） spectroscope. The toughness of the film prepared by this kind of hybrid aqueous dispersion was excellent, as it was enhanced appreciably by commixing with a small amount of poly（St-co-Ac） emulsion. Some amino-polysiloxane modified hybrid aqueous dispersions were also prepared and the properties of the modified dispersions and their films were investigated. The experimental results showed that the film prepared with such an amino-polysiloxane modified hybrid dispersion exhibited excellent hydrophobicity and low surface energy after heat treatment for 1.5 h, during which the formation of the graft copolymer was observed. The surface energy of this film decreases as a result of the enrichment of siloxane segments on the film surface.
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support from the National Natural Science Foundation of China(Grant 52222301,21971047,and 22171055)the Guangdong Natural Science Foundation for Distinguished Young Scholar(Grant 2022B1515020078)the Science and Technology Program of Guangzhou(Grant 202102020631).
文摘Here,we demonstrate the use of branched macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agents in RAFT dispersion polymerization,to access branched block copolymers as well as well-defined branched block copolymer assemblies.Two types of branched macro-RAFT agents were first synthesized by using either a monofunctional chain transfer monomer or a difunctional chain transfer monomer in RAFT polymerization,and subsequently utilized in RAFT dispersion polymerization.It was found that only branched macro-RAFT agents synthesized from the difunctional chain transfer monomer could lead to colloidally stable assemblies with well-defined morphologies.Reaction conditions including monomer concentration,degree of polymerization (DP) of the core-forming block,and DP of the solvophilic segment on morphologies of branched block copolymer assemblies were investigated in detail.Size exclusion chromatography (SEC) analysis further confirmed the successful formation of branched block copolymers by using branched macro-RAFT agents.This work on the synthesis of branched block copolymer assemblies by RAFT dispersion polymerization offers new opportunities for the rational design of polymer assemblies with well-defined structures.
基金Supported by the National Natural Science Foundation of China(50573005)
文摘A novel multifunctional macromolecular organolithium initiator （PD-Sn-（RLi）3） was prepared via living anionic polymerization and used for the synthesis of miktoarm star copolymers in cyclohexane. The average molecular weight, polydispersity index, microstructure and unit composition of the miktoarm star copolymers were characterized with GPC and 1H-NMR. Performances of the miktoarm star styrene-butadiene rubbers were investigated in comparison with those of the blend rubbers such as the tin-coupled star-shaped random copolymers of styrene-butadiene rubber（S-SBR）/natural rubber （NR） blend rubber and S-SBR/Cis-1, 4-polybutadiene rubber （Cis-BR） blend rubber.
基金Science and Technology Bureau of Nangtong in Jiangsu Province,China(No.A5035)Depart ment of Education,Jiangsu Province,China(No.J HZD06-30)
文摘A series of new-type nanometer TiO2 modified polyacrylic copolymer sizing agent were synthesized from acrylic acid, ethyl acrylate, nanometer TiO2, oleic acid etc. by orthogonal design method. Results of the studies show that the synthetic method used in this paper was a new way and had never been found in the synthesis of acrylate sizing agent, and that the properties of those new-type size-agent were be improved, which had potential for substituting PVA (polyvinyl alcohol) sizing agent. The technology for solving the problem of nano-scale powder agglomeration and dispersion were also studied. The transmission electron microscope (TEM) observation showed that nano-TiO2had good dispersion and stability in aqueous solution and in sizing agent solution.
基金Project supported by the National Natural Science Foundation of China(Nos.51872203 and 51572196)。
文摘The purpose of this study was to investigate the change in the physical and mechanical properties of styrene-butadiene copolymer(SB)dispersion-modified calcium sulfoaluminate(CSA)cement mortar as it aged from 28 to 360 d,and cured at different temperatures and relative humidities.The results show that the mechanical properties of reference mortar(RM)of CSA cement,including its flexural,compressive,and tensile bond strength,showed a reduction after a certain time,but its water capillary absorption was hardly affected by age.When SB dispersion was added,there was no reduction in mechanical strength.The amount of SB added did matter.Addition of 5% SB had a negative effect on most properties compared with RM,except for tensile bond strength.However,the properties of SB-modified mortar(SBMM)were enhanced significantly as the amount of SB was increased from 5% to 20%.Temperature change had different effects on the properties of RM and SBMM.High temperature was beneficial to early flexural and compressive strength development of RM,but caused serious strength reduction at later stages.High temperature enhanced the development of tensile bond strength of RM.Increasing temperature enhanced properties of SBMM,including flexural,compressive,and tensile bond strength.Higher relative humidity improved all measured properties of all mortars.Scanning electron microscope(SEM)observations of the morphology of RM and SBMM at 360 d cured under different conditions accounted well for the changes in mechanical properties.
基金financially supported by the National Natural Science Foundation of China(Nos.51173157 and 51173165)the Fundamental Research Funds for the Central Universities(No.2013QNA4048)
文摘We reported an approach to reconstruct the complex phase morphology of impact polypropylene copolymer （IPC） with core-shell dispersed particles and to optimize its toughness in approximate shear condition. The molten-state annealing results indicate that the phase structure with core-shell dispersed particles is unstable and could be completely destroyed by static annealing, resulting in the degradation of impact strength. By using a co-rotating twin screw extruder, we found that the dispersed particle with core-shell structure could be rebuilt in appropriate condition with the recovery of excellent impact strength due to both the huge interfacial tension during solidification and the great difference in viscosity of components. Results reveal that almost all the extruded IPCs show the impact strength 60%-90% higher than that of annealed IPCs at room temperature. And the twice-extruded IPC shows the highest impact strength, 446% higher than that of IPC annealed for 30 min. As for low temperature tests, the impact strength of extruded IPCs also increases by 33%-58%. According to adjusting the processing conditions including extrusion speed, extrusion frequency and temperature, an optimization of toughness was well established.
