Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl...Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction termi-nating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emul-sion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containingvarious concentrations of PEO-A was studied. In all cases stable emulsion coplymerizationsof MMA and BA were obtained. The stabilizing effect was found to be dependent on themolecular weight and the feed amount of the macromonomer.展开更多
Effects of branches on the crystallization kinetics of polypropylene-g-polystyrene （PP-g-PS） and polypropylene-g- poly（n-butyl acrylate） （PP-g-PnBA） graft copolymers with well-defined molecular structures were s...Effects of branches on the crystallization kinetics of polypropylene-g-polystyrene （PP-g-PS） and polypropylene-g- poly（n-butyl acrylate） （PP-g-PnBA） graft copolymers with well-defined molecular structures were systematically investigated by DSC. The Avrami equation was used to analyze the isothermal crystallization process, while the analysis of nonisothermal crystallization process was based on the Jeziorny-modified Avrami model and Mo model. The kinetics results of isothermal and nonisothermal crystallization verified the peculiar effects of branches on the crystallization process of PP backbones in PP-g-PS and PP-g-PnBA graft copolymers： on one hand, the interaction between branches （n-n interaction between PS branches, or dipole-dipole interaction between PnBA branches） restrained the mobility and reptation ability of the PP backbones, which hindered the crystallization process; on the other hand, the heterogeneous nucleation effect resulting from the branched structure and fluctuation-assisted nucleation mechanism （caused by microphase separation between the PS or PnBA rich phase and the PP rich phase） became more pronounced with increasing branch length, which facilitated the crystallization process.展开更多
Magnesium hydroxide(MH) whiskers were modified via in situ polymerization of n-butyl acrylate and maleic anhydride. Sodium dodecyl sulfonate was used as emulsifier. The modifying effect was evaluated by using contact ...Magnesium hydroxide(MH) whiskers were modified via in situ polymerization of n-butyl acrylate and maleic anhydride. Sodium dodecyl sulfonate was used as emulsifier. The modifying effect was evaluated by using contact angle and activation index. The thermal stability,functional groups, structure, morphology, phase composition and surface element valence of MH whiskers were characterized by thermogravimetry-differential scanning calorimetry(TG-DSC), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Results reveal that the contact angle and activation index of modified MH whiskers are 105°and 76.5%, the thermal stability shows little change, and the decomposition temperature ranges between 38 and419 ℃. The copolymer of n-butyl acrylate and maleic anhydride absorbed on the surface of MH whiskers leads to the increased diameter and makes the surface of whiskers be rougher. Furthermore, the absorption of element C on the surface of MH whiskers increases, and the diffraction intensity of C 1 s spectra increases; thus, the compatibility of whiskers in the organic phase can be improved significantly. Lastly, the surface molecular model of MH whiskers modified via in situ copolymerization of n-butyl acrylate and maleic anhydride is established.展开更多
AIM： To study the prevalence, predictors and control of bleeding following N-butyl 2 cyanoacrylate （NBC） sclerotherapy of gastric varix （GV）. METHODS： We analyzed case records of 1436 patients with portal hypert...AIM： To study the prevalence, predictors and control of bleeding following N-butyl 2 cyanoacrylate （NBC） sclerotherapy of gastric varix （GV）. METHODS： We analyzed case records of 1436 patients with portal hypertension, who underwent endoscopy during the past five years for variceal screening or upper gastrointestinal （GI） bleeding. Fifty patients with bleeding GV underwent sclerotherapy with a mean of 2 mL NBC for control of bleeding. Outcome parameters were primary hemostasis （bleeding control within the first 48 h）, recurrent bleeding （after 48 h of esophagogastro-duodenoscopy） and in-hospital mortality were analyzed. RESULTS： The prevalence of GV in patients with portal hypertension was 15% （220/1436） and the incidence of bleeding was 22.7% （50/220）. Out of the 50 bleeding GV patients, isolated gastric varices （IGV-Ⅰ） were seen in 22 （44%）, gastro-oesophageal varices （GOV） on lesser curvature （GOV-Ⅰ） in 16 （32%）, and GOV on greater curvature （GOV-Ⅱ） in 15 （30%）. IGV-Ⅰ was seen in 44% （22/50） patients who had bleeding as compared to 23% （39/170） who did not have bleeding （P 〈 0.003）. Primary hernostasis was achieved with NBC in all patients. Re-bleeding occurred in 7 （14%） patients after 48 h of initial sclerotherapy. Secondary hemostasis was achieved with repeat NBC sclerotherapy in 4/7 （57%）. Three patients died after repeat sclerotherapy, one during transjugular intrahepatic portosystemic stem shunt （TIPSS）, one during surgery and one due to uncontrolled bleeding. Treatment failure-related mortality rate was 6% （3/50）. CONCLUSION： GV can be seen in 15% of patients with portal hypertension and the incidence of bleeding is 22.7%. NBC is highly effective in controlling GV bleeding. In hospital mortality of patients with bleeding GV is 6%.展开更多
Background:To evaluate the safety and efficacy of percutaneous transcatheter super-selective renal arterial embolization(SRAE)with N-butyl cyanoacrylate(NBCA)for iatrogenic renal hemorrhage.Methods:Between January 201...Background:To evaluate the safety and efficacy of percutaneous transcatheter super-selective renal arterial embolization(SRAE)with N-butyl cyanoacrylate(NBCA)for iatrogenic renal hemorrhage.Methods:Between January 2014 and December 2019,45 patients(including 18 patients with coagulopathy),who underwent percutaneous transcatheter SRAE with NBCA for iatrogenic renal hemorrhage at our institution,were retrospectively reviewed.The technical success rate,clinical success rate,and embolization-related complications were analyzed.The values of estimated glomerular filtration rate(eGFR),serum creatinine(sCr),and serum urea(sUr)were analyzed at the time of pre-SRAE,post-SRAE,and last follow-up to evaluate the effects of NBCA-based SRAE on renal function.Results:Diagnostic renal arteriography revealed contrast extravasation in 18 patients and pseudoaneurysms in 27 patients.NBCA mixed with iodized oil in a 1:2–1:4 ratio was the sole embolic agent.No procedure-related mortality or major complications occurred.The technical and clinical success rates were both 100%.The values of eGFR,sCr and sUr were not found to be significantly different between pre-SRAE,post-SRAE and last follow-up(eGFR:91.52±21.17 vs.90.98±22.11 vs.92.14±23.51 mL/min/1.73 m^(2),p=0.729;sCr:74.73±11.08 vs.75.27±12.43 vs.73.95±10.14μmol/L,p=0.543;sUr:5.69±0.84 vs.5.71±0.96 vs.5.70±0.79,p=0.515,respectively).Conclusions:Percutaneous transcatheter SRAE with NBCA is a safe and effective treatment modality for iatrogenic renal hemorrhage with no deterioration of renal function.展开更多
Controlled radical photopolymerization of n-butyl methacrylate（n-BMA） mediated by 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy（HTEMPO） was carried out in bulk at ambient temperature. It was found that obtained n...Controlled radical photopolymerization of n-butyl methacrylate（n-BMA） mediated by 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy（HTEMPO） was carried out in bulk at ambient temperature. It was found that obtained n-BMA homopolymers exhibited narrow polydispersities of around 1.4, which was characterized by GPC. Plots of number-average molecular weight vs. conversion and Ln（[Mo]/[M]） vs. time were liner respectively, indicating that was a controlled photopolymerization.展开更多
The effects of oxygen on the chemical structure, morphology, hydrophilicity and drug release behavior of radio-frequency plasma poly n- butyl methacrylate （PPBMA） thin film were carded out for the first time. ATR-FT...The effects of oxygen on the chemical structure, morphology, hydrophilicity and drug release behavior of radio-frequency plasma poly n- butyl methacrylate （PPBMA） thin film were carded out for the first time. ATR-FTIR and XPS showed that oxygen had little influence on the chemical structure and composition of PPBMAs, which did not agree with the thought that the presence of oxygen gas would increase the oxidized carbon functionalities in the plasma polymer. SEM and static contact angle measurement indicated that in case of deposition with oxygen, the smoothness and hydrophilicity of PPBMA were dramatically improved. The drug release behavior showed that drug release from the PPBMA coating without oxygen was biphasic patterns, while from PPBMA coating with oxygen was Higuchi release. These results were helpful for the design and tailoring of the PPBMA polymer film and other of plasma polymers film, but could provide a new idea for the drug release controlled form.展开更多
AIM: To compare the efficacy and safety of bronchial artery embolization (BAE) with n-butyl cyanoacrylate (NBCA) and gelatin sponge particles (GSPs). METHODS: Six healthy female swine were divided into two groups to b...AIM: To compare the efficacy and safety of bronchial artery embolization (BAE) with n-butyl cyanoacrylate (NBCA) and gelatin sponge particles (GSPs). METHODS: Six healthy female swine were divided into two groups to be treated with BAE using NBCA-lipiodol (NBCA-Lp) and using GSPs. The occlusive durability, the presence of embolic materials, the response of the vessel wall, and damage to the bronchial wall and pulmonary parenchyma were compared. RESULTS: No animals experienced any major complication. Two days later, no recanalization of the bronchial artery was observed in the NBCA-Lp group, while partial recanalization was seen in the GSP group. Embolic materials were not found in the pulmonary artery or pulmonary vein. NBCA-Lp was present as a bubble-like space in bronchial branch arteries of 127-1240 μm, and GSPs as reticular amorphous substance of 107-853 μm. These arteries were in the adventitia outside the bronchial cartilage but not in the fine vessels inside the bronchial cartilage. No damage to the bronchial wall and pulmonary parenchyma was found in either group. Red cell thrombus, stripping of endothelial cells, and infiltration of inflammatory cells was observed in vessels embolized with NBCA-Lp or GSP. CONCLUSION: NBCA embolization is more potent than GSP with regard to bronchial artery occlusion, and both materials were present in bronchial branch arteries≥100 μm diameter.展开更多
Poly(ethylene glycol)-poly(n-butyl cyanoacrylate)(PEG-PBCA)is a remarkable drug delivery carrier for permeating blood-brain barrier.In this work,a novel high-gravity procedure was reported to intensify Knoevenagel con...Poly(ethylene glycol)-poly(n-butyl cyanoacrylate)(PEG-PBCA)is a remarkable drug delivery carrier for permeating blood-brain barrier.In this work,a novel high-gravity procedure was reported to intensify Knoevenagel condensation-Michael addition polymerization of PEG-PBCA.A series of PEG-PBCA containing different block ratios were synthesized with narrow molecular weight distribution of polydispersity indexes less than 1.1.Furthermore,the reaction time reduced 60%compared to conventional stirred tank reactor process.Chemical structures of as-prepared polymers were characterized.In vitro drug delivery performance was evaluated.The cytotoxicity of PEG-PBCA to brain microvessel endothelial cells(BMVEC)decreases with the extension of the PEG chain and the shortening of the PBCA chain.The polymer cellular uptake to BMVECs was better after improving hydrophilicity by PEG block.Results of bloodbrain barrier permeability demonstrated that medium length of PBCA chain and short PEG chain are favorable for hydrophobic Nile red permeation,while long PEG chain and short PBCA chain are beneficial to delivery water-soluble doxorubicin hydrochloride(Dox).The average apparent permeability coeffi-cient increased 1.7 and 0.25 times than that of raw Nile red and Dox,respectively.High-gravity intensi-fied condensation polymerization should have great potential in brain drug delivery system.展开更多
By means of initiation of the high temperature and shearing stress of an extruder,we synthesized the graft copolymer of starch with acrylate monomers based on the simple dry method.The eff...By means of initiation of the high temperature and shearing stress of an extruder,we synthesized the graft copolymer of starch with acrylate monomers based on the simple dry method.The effects of reaction conditions on graft copolymerization were discussed. Grafted starch used as a compatibilizer for the blend system of starch and polyethylene was further investigated. The results indicate that grafted starch as a compatibilizer can improve the mechanical properties and rheologic properties of the blend of starch and polyethylene.展开更多
Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolyme...Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolymerization. The variables affecting the degree of grafting, such as the time of UV （Ultraviolet-visible） irradiation and the concentrations of the methyl acrylate and photoinitiator, were investigated. The graft copolymer membranes were prepared by the phase inversion method. The chemical and morphological changes were characterized by attenuated total reflection-Fourier transform infrared spectroscopy （ATR/FT-IR）, scanning electron microscopy, and water contact angles measurements. Results revealed that methyl acrylate groups were present on the membranes and the graft degree of methyl acrylate had remarkable effect on the performance of membranes. Pure water contact angle on the membrane surface decreases with the increase of methyl acrylate graft degree, which indicated that the hydrophilicity of graft copolymer membranes was improved. The permeation fluxes of pure water and bovine serum albumin solution were measured to evaluate the antifouling property of graft copolymer membranes, the results of which have shown an enhancement of antifouling property for graft copolymer membranes.展开更多
In order to prepare hydrophobic waterborne polyurethane coatings with better performances, the silicon-containing waterborne polyurethane（SiWPU） with functional chain extender hydroxyethyl acrylate（HEA） was prepar...In order to prepare hydrophobic waterborne polyurethane coatings with better performances, the silicon-containing waterborne polyurethane（SiWPU） with functional chain extender hydroxyethyl acrylate（HEA） was prepared first, and then a series of silicon＆fluorine-containing polyurethane/acrylate（FSiPUA） emulsions were obtained with flourine containing acrylic monomer by seed emulsion polymerization, introducing micro-nano SiO2 into FSiPUA emulsion to make the final hybrid emulsion. The properties of Si WPU, FSiPUA and SiO2/FSiPUA were investigated by fourier transform infrared spectra（FTIR）, transmission electron microscope（TEM）, Scanning Electron Microscope（SEM） and some other analytical methods. The results revealed that FSiPUA emulsion particles possessed composite core-shell structure and FSiPUA films with suitable ratio performed better than Si WPU films in hardness, water resistance and solvent resistance. The SiO2/FSiPUA films with micro-nano dual roughness structure showed a water contact angle of 136° with good resistance to acid and alkali.展开更多
Unsaturated polyester resin （UPR）/acrylate-terminated polyurethane （ATPU）/organo-modified montmorillonite （OMMT） nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prep...Unsaturated polyester resin （UPR）/acrylate-terminated polyurethane （ATPU）/organo-modified montmorillonite （OMMT） nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prepared by the sequential mixing, i.e. mixture of the ATPU and styrene （S） and OMMT were prepared in the first step; UPR was then added to the pre-intercalates of ATPU/S/OMMT. Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT. Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites, but the tensile strength, flexural strength and heat resistance of the materials are obviously decreased. When the weight ratio between UPR, ATPU and OMMT were 82：15：3, the impact strength and heat distortion-temperature of nanocomposite were greatly improved, meanwhile there was little change for other properties of the nanocomposites. The synergistic enhancement effects of ATPU and OMMT on the composites were observed. The structures and morphology of the composites were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.展开更多
Two kinds of UV curable polyurethane acrylate oligomers （PUPA and PUCA） were synthesized via the addition reaction between isophorone diisocyanate （IPDI） and polyethylene glycol monoacrylate （PEA6） or polycaprol...Two kinds of UV curable polyurethane acrylate oligomers （PUPA and PUCA） were synthesized via the addition reaction between isophorone diisocyanate （IPDI） and polyethylene glycol monoacrylate （PEA6） or polycaprolactone modified hydroxyethyl acrylate （PCLA2）. The structures of PUPA and PUCA were characterized by Fourier transform infrared spectroscopy （FT-IR）, IH nuclear magnetic resonance （^H NMR）, gel permeation chromatography （GPC） and differential scanning calorimeter （DSC）, and the thermal stability and dynamic mechanical thermal properties of their cured films were measured by thermogravimetric analysis （TGA） and dynamic mechanical analysis （DMA）, respectively. The viscosity of the oligomers and mechanical properties of the cured films were also studied. The results show that both oligomers have narrow molecular weight distribution. The viscosity of PUPA is 2.310 Pa.s at 25 ℃, while that of PUCA is： up to 3.980 Pa-s. The UV cured PUPA and PUCA films have homogeneous phase structure, and the PUCA film shows higher glass transition temperature and storage modulus. Furthermore, the PUCA film possesses better mechanical properties than PUPA, while the latter shows better alkali resistance.展开更多
The dynamic mechanical properties of a new blend system consisting of phenol resin and polar polymer (acrylaterubber and/or chlorinated polypropylene) were investigated. It was found that the addition of phenol resin ...The dynamic mechanical properties of a new blend system consisting of phenol resin and polar polymer (acrylaterubber and/or chlorinated polypropylene) were investigated. It was found that the addition of phenol resin to acrylate rubberand its incompatible blend can cause a remarkable improvement in the temperature dependence of the loss tangent. As a result, the present blends are very good damping materials.展开更多
A novel ohthalazinone modified epoxy acrylate resin for the high temperature resistant ultravioet （UV） curable coating.was syn-thesized.The methacrylated epoxy resins obtained were utilized to UV radiation curing by...A novel ohthalazinone modified epoxy acrylate resin for the high temperature resistant ultravioet （UV） curable coating.was syn-thesized.The methacrylated epoxy resins obtained were utilized to UV radiation curing by taking 2.5% （wt%） of photoinitiator in combination with 20% （wt%） of diluent, and generated the interpenetraring polymer networks. The cured film had good thermal and chemical stability.展开更多
A novel UV-curable prepolymer polypropyleneglycol diglycidyl ether diacrylate （PPGGEA） was synthesized by utilizing polypropyleneglycol diglycidyl ether （PPGGE） and acrylic acid （AA） as starting materials, N, N-...A novel UV-curable prepolymer polypropyleneglycol diglycidyl ether diacrylate （PPGGEA） was synthesized by utilizing polypropyleneglycol diglycidyl ether （PPGGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were in the following： the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ~C, and the molar ratio of PPGGE to AA was 1：2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized PPGGEA to prepare a kind of UV-cured coating. The mechanical properties of the UV-cured films were determined, giving 29.99 MPa of tensile strength, 834.27 MPa of the Young＇s modulus and 5.66% of elongation at tear.展开更多
The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate ov...The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate over a calcium sulfate catalyst, with various promoters, has been carried out to identify potential catalyst/promoter combinations for acrylate production. The best catalyst for methyl acrylate formation in this study has been calcium sulfate, with cupric sulfate and phosphates as promoters. The optimal mass ratio of m（CaSOa） ： m（CuSOa） ： m（Na2HPO4） ： m（KH2PO4） is 150.0 ： 13.8 ： 2.5 ： 1.2. Effects of carrier gas, reaction temperature, feed concentration as well as contact time on the dehydration of methyl lactate have been investigated. With nitrogen as a carrier gas, a combined yield of acrylic acid and methyl acrylate is 63.9% from 60% （by mass） methyl lactate at 400℃ with 7.7 seconds contact time.展开更多
The PAL was synthesized with BA,MMA and some monomers containing carboxyl groups（for example,acrylic acid（AA） and methacrylic acid（MAA）） as co-monomers by semi-continuous seeded emulsion polymerization technique...The PAL was synthesized with BA,MMA and some monomers containing carboxyl groups（for example,acrylic acid（AA） and methacrylic acid（MAA）） as co-monomers by semi-continuous seeded emulsion polymerization technique.The influences of alkalinization temperature,the feeding manner of AA or MAA on the particles size,rheological properties and carboxyl distribution of the latex were discussed,and the rheological mechanism was analyzed.The experimental results show that the PAL system has preferable viscosity and particle size when the alkalinization temperature is 50 ℃.Different distribution of carboxyl group in the particles and different resultant rheological properties are obtained by different feeding manner of AA or MAA into the system.The TEM images show that the particle is a smooth globe with carboxyl group concentrating on the surface and stabilized with electric double layer and nonionic adsorbed layer.The concentration of carboxyl functional group on the surface of particles can be achieved by the specific polymerization technique.The rheologyical properties are determined by accretion of particle volume and variation of the two phase volume ratio resulted from the carboxyl group spreading layer.展开更多
Photoinitiated inverse emulsion polymerization of sodium acrylate(AANa)in kerosene was carried out at room orlower temperature,using 2,2-dimethoxy-2-phenylacetophenone(DMPA)as the initiator.Kinetic investigations indi...Photoinitiated inverse emulsion polymerization of sodium acrylate(AANa)in kerosene was carried out at room orlower temperature,using 2,2-dimethoxy-2-phenylacetophenone(DMPA)as the initiator.Kinetic investigations indicated thatthe polymerization could be completed in about 30 min and produce polymer with high molecular weight(10~6～10~7).It wasfound that monomer droplets are the main sites for the polymerization(nucleation).With the increase of DMPAconcentration,polymerization rate(R_p)reaches a maximum value while molecular weight of the produced polymer has anadverse result,but the dependence of R_p on incident light intensity is similar.Influences of other parameters such asmonomer concentration,emulsifier content and reaction temperature,etc.were also studied.At lower pH values of waterphase,R_p depends strongly on the pH due to the electrostatic interaction between the ionized radicals and the monomer.Athigher pH,R_p shows a slight dependence on pH.展开更多
文摘Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction termi-nating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emul-sion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containingvarious concentrations of PEO-A was studied. In all cases stable emulsion coplymerizationsof MMA and BA were obtained. The stabilizing effect was found to be dependent on themolecular weight and the feed amount of the macromonomer.
基金financially supported by the National Natural Science Foundation of China for the projects(Nos.51233005 and 51073149)
文摘Effects of branches on the crystallization kinetics of polypropylene-g-polystyrene （PP-g-PS） and polypropylene-g- poly（n-butyl acrylate） （PP-g-PnBA） graft copolymers with well-defined molecular structures were systematically investigated by DSC. The Avrami equation was used to analyze the isothermal crystallization process, while the analysis of nonisothermal crystallization process was based on the Jeziorny-modified Avrami model and Mo model. The kinetics results of isothermal and nonisothermal crystallization verified the peculiar effects of branches on the crystallization process of PP backbones in PP-g-PS and PP-g-PnBA graft copolymers： on one hand, the interaction between branches （n-n interaction between PS branches, or dipole-dipole interaction between PnBA branches） restrained the mobility and reptation ability of the PP backbones, which hindered the crystallization process; on the other hand, the heterogeneous nucleation effect resulting from the branched structure and fluctuation-assisted nucleation mechanism （caused by microphase separation between the PS or PnBA rich phase and the PP rich phase） became more pronounced with increasing branch length, which facilitated the crystallization process.
基金financially supported by the National Natural Science Foundation of China (No.51272163)
文摘Magnesium hydroxide(MH) whiskers were modified via in situ polymerization of n-butyl acrylate and maleic anhydride. Sodium dodecyl sulfonate was used as emulsifier. The modifying effect was evaluated by using contact angle and activation index. The thermal stability,functional groups, structure, morphology, phase composition and surface element valence of MH whiskers were characterized by thermogravimetry-differential scanning calorimetry(TG-DSC), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Results reveal that the contact angle and activation index of modified MH whiskers are 105°and 76.5%, the thermal stability shows little change, and the decomposition temperature ranges between 38 and419 ℃. The copolymer of n-butyl acrylate and maleic anhydride absorbed on the surface of MH whiskers leads to the increased diameter and makes the surface of whiskers be rougher. Furthermore, the absorption of element C on the surface of MH whiskers increases, and the diffraction intensity of C 1 s spectra increases; thus, the compatibility of whiskers in the organic phase can be improved significantly. Lastly, the surface molecular model of MH whiskers modified via in situ copolymerization of n-butyl acrylate and maleic anhydride is established.
文摘AIM： To study the prevalence, predictors and control of bleeding following N-butyl 2 cyanoacrylate （NBC） sclerotherapy of gastric varix （GV）. METHODS： We analyzed case records of 1436 patients with portal hypertension, who underwent endoscopy during the past five years for variceal screening or upper gastrointestinal （GI） bleeding. Fifty patients with bleeding GV underwent sclerotherapy with a mean of 2 mL NBC for control of bleeding. Outcome parameters were primary hemostasis （bleeding control within the first 48 h）, recurrent bleeding （after 48 h of esophagogastro-duodenoscopy） and in-hospital mortality were analyzed. RESULTS： The prevalence of GV in patients with portal hypertension was 15% （220/1436） and the incidence of bleeding was 22.7% （50/220）. Out of the 50 bleeding GV patients, isolated gastric varices （IGV-Ⅰ） were seen in 22 （44%）, gastro-oesophageal varices （GOV） on lesser curvature （GOV-Ⅰ） in 16 （32%）, and GOV on greater curvature （GOV-Ⅱ） in 15 （30%）. IGV-Ⅰ was seen in 44% （22/50） patients who had bleeding as compared to 23% （39/170） who did not have bleeding （P 〈 0.003）. Primary hernostasis was achieved with NBC in all patients. Re-bleeding occurred in 7 （14%） patients after 48 h of initial sclerotherapy. Secondary hemostasis was achieved with repeat NBC sclerotherapy in 4/7 （57%）. Three patients died after repeat sclerotherapy, one during transjugular intrahepatic portosystemic stem shunt （TIPSS）, one during surgery and one due to uncontrolled bleeding. Treatment failure-related mortality rate was 6% （3/50）. CONCLUSION： GV can be seen in 15% of patients with portal hypertension and the incidence of bleeding is 22.7%. NBC is highly effective in controlling GV bleeding. In hospital mortality of patients with bleeding GV is 6%.
文摘Background:To evaluate the safety and efficacy of percutaneous transcatheter super-selective renal arterial embolization(SRAE)with N-butyl cyanoacrylate(NBCA)for iatrogenic renal hemorrhage.Methods:Between January 2014 and December 2019,45 patients(including 18 patients with coagulopathy),who underwent percutaneous transcatheter SRAE with NBCA for iatrogenic renal hemorrhage at our institution,were retrospectively reviewed.The technical success rate,clinical success rate,and embolization-related complications were analyzed.The values of estimated glomerular filtration rate(eGFR),serum creatinine(sCr),and serum urea(sUr)were analyzed at the time of pre-SRAE,post-SRAE,and last follow-up to evaluate the effects of NBCA-based SRAE on renal function.Results:Diagnostic renal arteriography revealed contrast extravasation in 18 patients and pseudoaneurysms in 27 patients.NBCA mixed with iodized oil in a 1:2–1:4 ratio was the sole embolic agent.No procedure-related mortality or major complications occurred.The technical and clinical success rates were both 100%.The values of eGFR,sCr and sUr were not found to be significantly different between pre-SRAE,post-SRAE and last follow-up(eGFR:91.52±21.17 vs.90.98±22.11 vs.92.14±23.51 mL/min/1.73 m^(2),p=0.729;sCr:74.73±11.08 vs.75.27±12.43 vs.73.95±10.14μmol/L,p=0.543;sUr:5.69±0.84 vs.5.71±0.96 vs.5.70±0.79,p=0.515,respectively).Conclusions:Percutaneous transcatheter SRAE with NBCA is a safe and effective treatment modality for iatrogenic renal hemorrhage with no deterioration of renal function.
基金Financially supports from the National Natural Science Foundation of China(No.20274023 and 20474036)Guangdong Province Natural Science Foundation(No.021241)are gratefully acknowledged.
文摘Controlled radical photopolymerization of n-butyl methacrylate（n-BMA） mediated by 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy（HTEMPO） was carried out in bulk at ambient temperature. It was found that obtained n-BMA homopolymers exhibited narrow polydispersities of around 1.4, which was characterized by GPC. Plots of number-average molecular weight vs. conversion and Ln（[Mo]/[M]） vs. time were liner respectively, indicating that was a controlled photopolymerization.
文摘The effects of oxygen on the chemical structure, morphology, hydrophilicity and drug release behavior of radio-frequency plasma poly n- butyl methacrylate （PPBMA） thin film were carded out for the first time. ATR-FTIR and XPS showed that oxygen had little influence on the chemical structure and composition of PPBMAs, which did not agree with the thought that the presence of oxygen gas would increase the oxidized carbon functionalities in the plasma polymer. SEM and static contact angle measurement indicated that in case of deposition with oxygen, the smoothness and hydrophilicity of PPBMA were dramatically improved. The drug release behavior showed that drug release from the PPBMA coating without oxygen was biphasic patterns, while from PPBMA coating with oxygen was Higuchi release. These results were helpful for the design and tailoring of the PPBMA polymer film and other of plasma polymers film, but could provide a new idea for the drug release controlled form.
文摘AIM: To compare the efficacy and safety of bronchial artery embolization (BAE) with n-butyl cyanoacrylate (NBCA) and gelatin sponge particles (GSPs). METHODS: Six healthy female swine were divided into two groups to be treated with BAE using NBCA-lipiodol (NBCA-Lp) and using GSPs. The occlusive durability, the presence of embolic materials, the response of the vessel wall, and damage to the bronchial wall and pulmonary parenchyma were compared. RESULTS: No animals experienced any major complication. Two days later, no recanalization of the bronchial artery was observed in the NBCA-Lp group, while partial recanalization was seen in the GSP group. Embolic materials were not found in the pulmonary artery or pulmonary vein. NBCA-Lp was present as a bubble-like space in bronchial branch arteries of 127-1240 μm, and GSPs as reticular amorphous substance of 107-853 μm. These arteries were in the adventitia outside the bronchial cartilage but not in the fine vessels inside the bronchial cartilage. No damage to the bronchial wall and pulmonary parenchyma was found in either group. Red cell thrombus, stripping of endothelial cells, and infiltration of inflammatory cells was observed in vessels embolized with NBCA-Lp or GSP. CONCLUSION: NBCA embolization is more potent than GSP with regard to bronchial artery occlusion, and both materials were present in bronchial branch arteries≥100 μm diameter.
基金This work was supported by National Key Research and Development Program of China(2016YFA0201701).
文摘Poly(ethylene glycol)-poly(n-butyl cyanoacrylate)(PEG-PBCA)is a remarkable drug delivery carrier for permeating blood-brain barrier.In this work,a novel high-gravity procedure was reported to intensify Knoevenagel condensation-Michael addition polymerization of PEG-PBCA.A series of PEG-PBCA containing different block ratios were synthesized with narrow molecular weight distribution of polydispersity indexes less than 1.1.Furthermore,the reaction time reduced 60%compared to conventional stirred tank reactor process.Chemical structures of as-prepared polymers were characterized.In vitro drug delivery performance was evaluated.The cytotoxicity of PEG-PBCA to brain microvessel endothelial cells(BMVEC)decreases with the extension of the PEG chain and the shortening of the PBCA chain.The polymer cellular uptake to BMVECs was better after improving hydrophilicity by PEG block.Results of bloodbrain barrier permeability demonstrated that medium length of PBCA chain and short PEG chain are favorable for hydrophobic Nile red permeation,while long PEG chain and short PBCA chain are beneficial to delivery water-soluble doxorubicin hydrochloride(Dox).The average apparent permeability coeffi-cient increased 1.7 and 0.25 times than that of raw Nile red and Dox,respectively.High-gravity intensi-fied condensation polymerization should have great potential in brain drug delivery system.
文摘By means of initiation of the high temperature and shearing stress of an extruder,we synthesized the graft copolymer of starch with acrylate monomers based on the simple dry method.The effects of reaction conditions on graft copolymerization were discussed. Grafted starch used as a compatibilizer for the blend system of starch and polyethylene was further investigated. The results indicate that grafted starch as a compatibilizer can improve the mechanical properties and rheologic properties of the blend of starch and polyethylene.
文摘Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolymerization. The variables affecting the degree of grafting, such as the time of UV （Ultraviolet-visible） irradiation and the concentrations of the methyl acrylate and photoinitiator, were investigated. The graft copolymer membranes were prepared by the phase inversion method. The chemical and morphological changes were characterized by attenuated total reflection-Fourier transform infrared spectroscopy （ATR/FT-IR）, scanning electron microscopy, and water contact angles measurements. Results revealed that methyl acrylate groups were present on the membranes and the graft degree of methyl acrylate had remarkable effect on the performance of membranes. Pure water contact angle on the membrane surface decreases with the increase of methyl acrylate graft degree, which indicated that the hydrophilicity of graft copolymer membranes was improved. The permeation fluxes of pure water and bovine serum albumin solution were measured to evaluate the antifouling property of graft copolymer membranes, the results of which have shown an enhancement of antifouling property for graft copolymer membranes.
基金Funded by the National High Technology Research and Development Program("863"Program)(No.2003AA305071)
文摘In order to prepare hydrophobic waterborne polyurethane coatings with better performances, the silicon-containing waterborne polyurethane（SiWPU） with functional chain extender hydroxyethyl acrylate（HEA） was prepared first, and then a series of silicon＆fluorine-containing polyurethane/acrylate（FSiPUA） emulsions were obtained with flourine containing acrylic monomer by seed emulsion polymerization, introducing micro-nano SiO2 into FSiPUA emulsion to make the final hybrid emulsion. The properties of Si WPU, FSiPUA and SiO2/FSiPUA were investigated by fourier transform infrared spectra（FTIR）, transmission electron microscope（TEM）, Scanning Electron Microscope（SEM） and some other analytical methods. The results revealed that FSiPUA emulsion particles possessed composite core-shell structure and FSiPUA films with suitable ratio performed better than Si WPU films in hardness, water resistance and solvent resistance. The SiO2/FSiPUA films with micro-nano dual roughness structure showed a water contact angle of 136° with good resistance to acid and alkali.
基金This research was supported by the Science and Technology Key Project of Guangdong(A1070203).
文摘Unsaturated polyester resin （UPR）/acrylate-terminated polyurethane （ATPU）/organo-modified montmorillonite （OMMT） nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prepared by the sequential mixing, i.e. mixture of the ATPU and styrene （S） and OMMT were prepared in the first step; UPR was then added to the pre-intercalates of ATPU/S/OMMT. Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT. Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites, but the tensile strength, flexural strength and heat resistance of the materials are obviously decreased. When the weight ratio between UPR, ATPU and OMMT were 82：15：3, the impact strength and heat distortion-temperature of nanocomposite were greatly improved, meanwhile there was little change for other properties of the nanocomposites. The synergistic enhancement effects of ATPU and OMMT on the composites were observed. The structures and morphology of the composites were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.
基金Project(2007168303) supported by Guangdong-Hong Kong Technology Cooperation Funding
文摘Two kinds of UV curable polyurethane acrylate oligomers （PUPA and PUCA） were synthesized via the addition reaction between isophorone diisocyanate （IPDI） and polyethylene glycol monoacrylate （PEA6） or polycaprolactone modified hydroxyethyl acrylate （PCLA2）. The structures of PUPA and PUCA were characterized by Fourier transform infrared spectroscopy （FT-IR）, IH nuclear magnetic resonance （^H NMR）, gel permeation chromatography （GPC） and differential scanning calorimeter （DSC）, and the thermal stability and dynamic mechanical thermal properties of their cured films were measured by thermogravimetric analysis （TGA） and dynamic mechanical analysis （DMA）, respectively. The viscosity of the oligomers and mechanical properties of the cured films were also studied. The results show that both oligomers have narrow molecular weight distribution. The viscosity of PUPA is 2.310 Pa.s at 25 ℃, while that of PUCA is： up to 3.980 Pa-s. The UV cured PUPA and PUCA films have homogeneous phase structure, and the PUCA film shows higher glass transition temperature and storage modulus. Furthermore, the PUCA film possesses better mechanical properties than PUPA, while the latter shows better alkali resistance.
基金This work was supported by the "The National High Technology Research and Development Program" of Ministry of Science and Technology of China (No. 2002AA333020).
文摘The dynamic mechanical properties of a new blend system consisting of phenol resin and polar polymer (acrylaterubber and/or chlorinated polypropylene) were investigated. It was found that the addition of phenol resin to acrylate rubberand its incompatible blend can cause a remarkable improvement in the temperature dependence of the loss tangent. As a result, the present blends are very good damping materials.
文摘A novel ohthalazinone modified epoxy acrylate resin for the high temperature resistant ultravioet （UV） curable coating.was syn-thesized.The methacrylated epoxy resins obtained were utilized to UV radiation curing by taking 2.5% （wt%） of photoinitiator in combination with 20% （wt%） of diluent, and generated the interpenetraring polymer networks. The cured film had good thermal and chemical stability.
基金the Innovatory Group Program of the Natural Science Foundation of Hubei Province(No.2004ABC001)the National"863"Hi-tech Foundation of China(No.2002AA6Z3083)
文摘A novel UV-curable prepolymer polypropyleneglycol diglycidyl ether diacrylate （PPGGEA） was synthesized by utilizing polypropyleneglycol diglycidyl ether （PPGGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were in the following： the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ~C, and the molar ratio of PPGGE to AA was 1：2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized PPGGEA to prepare a kind of UV-cured coating. The mechanical properties of the UV-cured films were determined, giving 29.99 MPa of tensile strength, 834.27 MPa of the Young＇s modulus and 5.66% of elongation at tear.
基金he Special Foundation for State Major Basic Research Program of China(2007CB707805,2004CCA05500)
文摘The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate over a calcium sulfate catalyst, with various promoters, has been carried out to identify potential catalyst/promoter combinations for acrylate production. The best catalyst for methyl acrylate formation in this study has been calcium sulfate, with cupric sulfate and phosphates as promoters. The optimal mass ratio of m（CaSOa） ： m（CuSOa） ： m（Na2HPO4） ： m（KH2PO4） is 150.0 ： 13.8 ： 2.5 ： 1.2. Effects of carrier gas, reaction temperature, feed concentration as well as contact time on the dehydration of methyl lactate have been investigated. With nitrogen as a carrier gas, a combined yield of acrylic acid and methyl acrylate is 63.9% from 60% （by mass） methyl lactate at 400℃ with 7.7 seconds contact time.
基金Funded by the National Natural Science Foundation of China (No.50803017)
文摘The PAL was synthesized with BA,MMA and some monomers containing carboxyl groups（for example,acrylic acid（AA） and methacrylic acid（MAA）） as co-monomers by semi-continuous seeded emulsion polymerization technique.The influences of alkalinization temperature,the feeding manner of AA or MAA on the particles size,rheological properties and carboxyl distribution of the latex were discussed,and the rheological mechanism was analyzed.The experimental results show that the PAL system has preferable viscosity and particle size when the alkalinization temperature is 50 ℃.Different distribution of carboxyl group in the particles and different resultant rheological properties are obtained by different feeding manner of AA or MAA into the system.The TEM images show that the particle is a smooth globe with carboxyl group concentrating on the surface and stabilized with electric double layer and nonionic adsorbed layer.The concentration of carboxyl functional group on the surface of particles can be achieved by the specific polymerization technique.The rheologyical properties are determined by accretion of particle volume and variation of the two phase volume ratio resulted from the carboxyl group spreading layer.
基金This work was supported by the Scientific Research Foundation for Youth(No.QN0404).
文摘Photoinitiated inverse emulsion polymerization of sodium acrylate(AANa)in kerosene was carried out at room orlower temperature,using 2,2-dimethoxy-2-phenylacetophenone(DMPA)as the initiator.Kinetic investigations indicated thatthe polymerization could be completed in about 30 min and produce polymer with high molecular weight(10~6～10~7).It wasfound that monomer droplets are the main sites for the polymerization(nucleation).With the increase of DMPAconcentration,polymerization rate(R_p)reaches a maximum value while molecular weight of the produced polymer has anadverse result,but the dependence of R_p on incident light intensity is similar.Influences of other parameters such asmonomer concentration,emulsifier content and reaction temperature,etc.were also studied.At lower pH values of waterphase,R_p depends strongly on the pH due to the electrostatic interaction between the ionized radicals and the monomer.Athigher pH,R_p shows a slight dependence on pH.
