A single-component anionic polyurethane emulsion has been prepared from polyepoxyglycol, tolylene diisocyanate, dimethoxypropionic acid and ethylene diamine via prepolymeration route. The effects of the molecular weig...A single-component anionic polyurethane emulsion has been prepared from polyepoxyglycol, tolylene diisocyanate, dimethoxypropionic acid and ethylene diamine via prepolymeration route. The effects of the molecular weight of polyether polyol, the ratio of isocyanate group to hydroxy group and the amount of dimethylolpropionic acid on the property of the PU film and its physical property have been investigated.展开更多
With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysi...With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.展开更多
A nanomicelle(denoted as TPGS/Ppa)was fabricated via the coassembly of the amphiphilic D-α-tocopheryl polyethylene glycol 1000 succinate(TPGS)and the hydrophobic photosensitizer pyropheophorbide a(Ppa)for photodynami...A nanomicelle(denoted as TPGS/Ppa)was fabricated via the coassembly of the amphiphilic D-α-tocopheryl polyethylene glycol 1000 succinate(TPGS)and the hydrophobic photosensitizer pyropheophorbide a(Ppa)for photodynamic therapy(PDT).The obtained nanomicelle possessed a spherical structure with a diameter of(18.0±2.2)nm and a zeta potential of approximately -18 mV.Besides,the nanomicelle exhibited excellent photostability,biocompatibility,and phototoxicity,and could effectively reach the tumor region via the enhanced permeability and retention effect.Additionally,it could be found that the TPGS/Ppa nanomicelle exhibited higher phototoxicity against 4T1 murine mammary cancer cells than free Ppa.In the 4T1 tumor-bearing mouse model,the nanomicelle showed an excellent antitumor therapeutic effect.This study develops a new type of photodynamic nanomicelle TPGS/Ppa,which can increase the accumulation of drugs and prolong their tumor retention time,providing a feasible strategy for realizing the delivery of small-molecule hydrophobic drugs and tumor PDT.展开更多
Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized...Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.展开更多
文摘A single-component anionic polyurethane emulsion has been prepared from polyepoxyglycol, tolylene diisocyanate, dimethoxypropionic acid and ethylene diamine via prepolymeration route. The effects of the molecular weight of polyether polyol, the ratio of isocyanate group to hydroxy group and the amount of dimethylolpropionic acid on the property of the PU film and its physical property have been investigated.
文摘With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.
文摘A nanomicelle(denoted as TPGS/Ppa)was fabricated via the coassembly of the amphiphilic D-α-tocopheryl polyethylene glycol 1000 succinate(TPGS)and the hydrophobic photosensitizer pyropheophorbide a(Ppa)for photodynamic therapy(PDT).The obtained nanomicelle possessed a spherical structure with a diameter of(18.0±2.2)nm and a zeta potential of approximately -18 mV.Besides,the nanomicelle exhibited excellent photostability,biocompatibility,and phototoxicity,and could effectively reach the tumor region via the enhanced permeability and retention effect.Additionally,it could be found that the TPGS/Ppa nanomicelle exhibited higher phototoxicity against 4T1 murine mammary cancer cells than free Ppa.In the 4T1 tumor-bearing mouse model,the nanomicelle showed an excellent antitumor therapeutic effect.This study develops a new type of photodynamic nanomicelle TPGS/Ppa,which can increase the accumulation of drugs and prolong their tumor retention time,providing a feasible strategy for realizing the delivery of small-molecule hydrophobic drugs and tumor PDT.
基金Supported by the Program of Jiangsu Development & Reform Commission(2005)the Industrial-ization Boosting Program of College Scientific Reserach Achievements of the Education Department of Jiangsu Province(JHB06-03)~~
文摘Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.
