Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interfac...Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interface anchoring,and inorganic particles have gained extensive attention recently owing to their large interfacial desorption energy,while their low affinity to bulk components is a drawback.In this study,an interfacial atom transfer radical polymerization(ATRP)technique was employed to grow polystyrene(PS)and poly(2-hydroxyethyl methacrylate)(PHEMA)simultaneously on different hemispheres of Br-functionalized SiO_(2) nanoparticles to stabilize a Pickering emulsion,whereby a brush-type Janus nanoparticle(SiO_(2)@JNP)was developed.The polymer brushes were well-characterized,and the Janus feature was validated by transmission electron microscope(TEM)observation of the sole hemisphere grafting of SiO_(2)-PS as a control sample.SiO_(2)@JNP was demonstrated to be an efficient compatibilizer for a PS/poly(methyl methacrylate)(PMMA)immiscible blend,and the droplet-matrix morphology was significantly refined.The mechanical strength and toughness of the blend were synchronously enhanced at a low content SiO_(2)@JNP optimized~0.9 wt%,with the tensile strength,elongation at break and impact strength increased by 17.7%,26.6%and 19.6%,respectively.This enhancement may be attributed to the entanglements between the grafted polymer brushes and individual components that improve the particle-bulk phase affinity and enforce interfacial adhesion.展开更多
The rising prevalence of drug-resistant Gram-positive pathogens,particularly methicillin-resistant Staphy-lococcus aureus(MRSA)and vancomycin-resistant Enterococci(VRE),poses a substantial clinical challenge.Biofilm-a...The rising prevalence of drug-resistant Gram-positive pathogens,particularly methicillin-resistant Staphy-lococcus aureus(MRSA)and vancomycin-resistant Enterococci(VRE),poses a substantial clinical challenge.Biofilm-associated infections exacerbate this problem due to their inherent antibiotic resistance and complex structure.Current antibiotic treatments struggle to penetrate biofilms and eradicate persister cells,leading to prolonged antibiotic use and increased resistance.Host defense peptides(HDPs)have shown promise,but their clinical application is limited by factors such as enzymatic degradation and difficulty in largescale preparation.Synthetic HDP mimics,such as poly(2-oxazoline),have emerged as effective alter-natives.Herein,we found that the poly(2-oxazoline),Gly-POX_(20),demonstrated rapid and potent activity against clinically isolated multidrug-resistant Gram-positive strains.Gly-POX_(20) showed greater stability under physiological conditions compared to natural peptides,including resistance to protease degradation.Importantly,Gly-POX_(20) inhibited biofilm formation and eradicated mature biofilm and demonstrated superior in vivo therapeutic efficacy to vancomycin in a MRSA biofilm-associated mouse keratitis model,suggesting its potential as a novel antimicrobial agent against drug-resistant Gram-positive bacteria,especially biofilm-associated infections.展开更多
Silk was grafted using 2-hydroxyethyl methacrylate(HEMA)by atom transfer radical polymerization(ATRP)method.The amino groups and hydroxyl groups on the side chains of the silk fibroin was reacted with 2-bromoisobutyry...Silk was grafted using 2-hydroxyethyl methacrylate(HEMA)by atom transfer radical polymerization(ATRP)method.The amino groups and hydroxyl groups on the side chains of the silk fibroin was reacted with 2-bromoisobutyryl bromide(BriB-Br)to obtain efficient macroinitiator for ATRP.And the macroinitiator was grafted with HEMA in water aqueous using CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine(PMDETA)as catalyst system.The effects of monomer concentration,the proportion of CuBr and PMDETA,grafting temperature and time on the silk grafting were discussed,and the optimal grafting technology was obtained.FT-IR characterization of the grafted silk showed a peak corresponding to HEMA,which indicated that HEMA was grafted onto the surface of silk.ATRP method could be applied on the silk modification and this technique provided a new way for silk grafting.展开更多
This work aimed at effectively utilizing the chemically depolymerized waste poly（ethylene terephthalate）（PET） fibers into useful products for the textile industry.PET fibers were glycolytically degraded by excess ...This work aimed at effectively utilizing the chemically depolymerized waste poly（ethylene terephthalate）（PET） fibers into useful products for the textile industry.PET fibers were glycolytically degraded by excess ethylene glycol as depolymerizing agent and zinc acetate dihydrate as catalyst.The glycolysis product,bis（2-hydroxyethyl） terephthalate（BHET）,was purified through repeated crystallization to get an average yield above 80%.Then,BHET was nitrated,reduced,and azotized to get diazonium salt.Finally,the produced diazonium salt was coupled with 1-（4-sulfophenyl）-3-methyl-5-pyrazolone to get azo dyestuff.The structures of BHET and azo dyestuff were identified by FT1 R and ^1H NMR spectra and elemental analysis.Nylon filaments dyed by the synthesized azo dyestuff with the dye bath pH from 4.14 to 5.88 showed bright yellow color.The performances of the dyestuff were described with dye uptake,color fastness,K/S,L^＊,a^＊,b^＊.and △E^＊ values.展开更多
This paper describes the fabrication, characterization and properties of a novel hybrid poly（ethylene glycol） （PEG） based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical red...This paper describes the fabrication, characterization and properties of a novel hybrid poly（ethylene glycol） （PEG） based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate （APS） and N, N, N/, NCtetramethylethylenediamine （TEMED） as initiators and N, NCmethylene bisacrylamide （BIS） as cross-linker at 60~C. To create a hybrid hydrogel, 0.2% （mass fraction） of MgA1 layered double hydroxide （LDH） was added to the aqueous solution by ultrasonic disper- sion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared （FTIR） spectroscopy, thermal gravimetric analysis （TGA） and scanning electron microscopy （SEM）, while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%--125% with a gel mass fraction of 83%--91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% （based on glycol）. The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.展开更多
目的:探究多聚胞嘧啶结合蛋白2[poly(C)-binding protein 2,PCBP2]如何通过调节铁死亡参与大别班达病毒(Dabie Banda virus,DBV)感染后的致病过程及其作用机制。方法:以人单核细胞系THP-1为模型,采用qRT-PCR和Western blot技术检测DBV...目的:探究多聚胞嘧啶结合蛋白2[poly(C)-binding protein 2,PCBP2]如何通过调节铁死亡参与大别班达病毒(Dabie Banda virus,DBV)感染后的致病过程及其作用机制。方法:以人单核细胞系THP-1为模型,采用qRT-PCR和Western blot技术检测DBV感染的THP-1细胞中PCBP2的mRNA及蛋白表达水平。通过透射电镜观察病毒感染下的线粒体结构变化,在THP-1细胞中构建了慢病毒介导的PCBP2过表达和敲低稳转细胞系。FerroOrange荧光探针检测Fe^(2+)水平,2,7-二氯荧光素二乙酸酯(2,7-dichlorofluorescein diacetate,DCFH-DA)探针测定活性氧(reactive oxygen species,ROS)水平,Western blot检测铁死亡相关溶质载体家族7成员11(solute carrier family 7 member 11,SLC7A11)和谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)蛋白表达,以评估PCBP2调控对铁死亡的影响。使用铁死亡诱导剂(RSL3、erastin)和抑制剂(Fer-1、Lip-1)处理细胞,qRT-PCR和免疫荧光检测病毒复制水平变化,探索PCBP2是否可以通过调控铁死亡影响DBV复制。结果:在DBV感染的细胞模型中,PCBP2的mRNA和蛋白表达水平显著下调,DBV感染诱导典型铁死亡特征(线粒体嵴减少、肿胀)。通过qRT-PCR和Western blot验证,PCBP2敲低和过表达的THP-1细胞系构建成功,PCBP2敲低下调了铁死亡相关基因SLC7A11和GPX4的表达,导致ROS和Fe^(2+)水平升高;相反,PCBP2过表达使得SLC7A11和GPX4的表达水平升高,ROS和Fe^(2+)的水平降低。半数组织培养感染剂量与蛋白水平的检测进一步证实:铁死亡诱导剂可部分抵消PCBP2过表达促病毒复制的效应,铁死亡抑制剂可部分逆转PCBP2敲低抑制病毒复制的效应。结论:研究发现PCBP2可以通过维持SLC7A11/GPX4系统功能抑制铁死亡,从而限制DBV复制。这不仅阐明了PCBP2在DBV感染中的调控作用,为发热伴血小板减少综合征(severe fever with thrombocytope-nia syndrome,SFTS)的发病机制提供了新见解,同时靶向PCBP2-铁死亡通路可能成为SFTS治疗的潜在策略,为抗病毒药物的研发提供新思路。展开更多
Multiarm star block copolymers hyperbranched polyethylenimine-b-poly（2-hydroxyethyl methacrylate） （HPEI-b- PHEMA） with average 28 PHEMA arms have been prepared by atom transfer radical polymerization （ATRP） of H...Multiarm star block copolymers hyperbranched polyethylenimine-b-poly（2-hydroxyethyl methacrylate） （HPEI-b- PHEMA） with average 28 PHEMA arms have been prepared by atom transfer radical polymerization （ATRP） of HEMA in a mixed solvent of methanol and water using a core-first strategy. The hyperbranched macroinitiator employed was prepared on the basis of well-defined hyperbranched polyethylenimine with Mw/Mn of 1.04 by amidation with 2-bromo-isobutyryl bromide. The polymerization condition was optimized to prepare star copolymers with narrow dispersity, and the variables included the volume ratio of methanol to water, the molar ratio of initiating site to CuC1 and the molar ratio of [CuCl]：[CuBr2]. Under the optimized polymerization condition, the lowest Mw/Mn value of the obtained star copolymers was around 1.3. Kinetic analysis showed that an induction period existed in the polymerization of HEMA. After this induction period, a linear dependence of ln（[M]0/[M]t） on time was observed. The obtained HPEI-b-PHEMA could adsorb hydrophilic molecules. The comparison with the star copolymer with hydrophobic core and hydrophilic PHEMA shell verified that both the hydrophilic core and shell could host the hydrophilic vips, but the amidated HPEI core was more effective than the PHEMA shell.展开更多
Poly(ethylene 2,5-furandicarboxylate)(PEF),a bioplastic synthesized via the polymerization of 2,5-furandicarboxylic acid(FDCA)with ethylene glycol,can be served as a substitute to petroleum-based polyethylene terephth...Poly(ethylene 2,5-furandicarboxylate)(PEF),a bioplastic synthesized via the polymerization of 2,5-furandicarboxylic acid(FDCA)with ethylene glycol,can be served as a substitute to petroleum-based polyethylene terephthalate(PET)due to its enhanced material properties.However,the fabrication of PEF with stable and desirable properties is still a challenge,largely due to the impurities in FDCA.In this study,a highly efficient purification strategy for FDCA was proposed,utilizing a dioxane/H_(2)O binary solvent system for effective crystallization.Furthermore,PEFs were synthesized from FDCA with varying impurity and the effects of these impurities were systematically characterized.The results revealed that impurities in FDCA could result in PEFs with relatively poor thermal properties.This study provides crucial insights for the impact of impurities on PEF properties and FDCA purification.展开更多
In the context of peaking carbon dioxide emissions and carbon neutrality,development of feasible methods for converting CO_(2)into high value-added chemicals stands out as a hot subject.In this study,P[D+COO^(−)][Br^(...In the context of peaking carbon dioxide emissions and carbon neutrality,development of feasible methods for converting CO_(2)into high value-added chemicals stands out as a hot subject.In this study,P[D+COO^(−)][Br^(−)][DBUH^(+)],a series of novel heterogeneous dual-ionic poly(ionic liquid)s(PILs)were synthesized readily from 2-(dimethylamino)ethyl methacrylate(DMAEMA),bromo-substituted aliphatic acids,organic bases and divinylbenzene(DVB).The structures,compositions and morphologies were characterized or determined by nuclear magnetic resonance(NMR),thermal gravimetric analysis(TGA),infrared spectroscopy(IR),scanning electron microscopes(SEM),and Brunauer-Emmett-Teller analysis(BET),etc.Application of the P[D+COO^(−)][Br^(−)][DBUH^(+)]series as catalysts in converting CO_(2)into cyclic carbonates showed that P[D+COO^(−)][Br^(−)][DBUH^(+)]-2/1/0.6was able to catalyze epiclorohydrin-CO_(2)cycloaddition the most efficiently.This afforded chloropropylene carbonate(CPC)in 98.4%yield with≥99%selectivity in 24 hr under solvent-and additive-free conditions at atmospheric pressure.Reusability experiments showed that recycling of the catalyst 6 times only resulted in a slight decline in the catalytic performance.In addition,it could be used for the synthesis of a variety of differently substituted cyclic carbonates in good to excellent yields.Finally,key catalytic active sites were probed,and a reasonable mechanism was proposed accordingly.In summary,this work poses an efficient strategy for heterogenization of dual-ionic PILs and provides amild and environmentally benign approach to the fixation and utilization of carbon dioxide.展开更多
A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The sa...A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The samples obtained from the synthesis were characterized by Fourier Transform-Infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (<sup>1</sup>H NMR), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The results show that the synthesis of the polymers is more feasible under neat conditions rather than solvent directed reaction. Moreover, the DSC data shows that the polystyrene obtained is amorphous in nature and therefore displayed only a glass transition signal rather than crystallization and melting peaks. In addition, this study indicates that homolopolymerization of styrene via free radical polymerization tends to be preferable in less polar solvents like THF than in non-polar solvents like benzene. Benzene might destabilize the formation of the reactive radicals leading to the formation of the products. In summary, the homolpolymerization of styrene is more feasible than the homopolymerization 2-hydroxyethyl methacrylate under the experimental setup used. Styrene is more reactive than 2-hydroxyethyl methacrylate than free radical polymerization reaction due in part of the generation of the benzylic radical intermediate which is more stable leading to the formation of products than alkyl radical which are less stable. Furthermore, polymerization of styrene under neat conditions is preferable in solvent-assisted environments. The choice of solvent for the synthesis of these polymers is crucial and therefore the selection of solvent that leads to the formation of a more stable reaction intermediate is more favorable. It is worth noting that the structure of the proposed copolymer consists of a highly polar and hydrophilic monomer, 2-hydroxyethyl methacrylate and a highly non-polar and hydrophobic monomer, styrene. These functionalities constitute an amphiphilic copolymer with diverse characteristics. A plausible explanation underlying our observations is that the reaction conditions employed in the synthesis of these copolymers might not be the right route required under free radical polymerization.展开更多
The preparation of TiO2/poly（L-lactide-co-ε-caprolactone）（PLCL） nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone（ε-CL）...The preparation of TiO2/poly（L-lactide-co-ε-caprolactone）（PLCL） nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone（ε-CL）.The resulting poly（ε-caprolactone）-grafted TiO2（g-TiO2） was characterized by Fourier transform infrared spectroscopy（FTIR）,thermogravimetric analysis（TGA） and transmission electron microscopy（TEM）.The g-TiO2can be uniformly dispersed in chloroform and the g-TiO2/PLCL nanocomposites were successfully fabricated through solvent-casting method.The effects of the content of g-TiO2nanoparticles on tensile properties and shape memory properties were investigated.A significant improvement in the tensile properties of the 5% g-TiO2/PLCL mass fraction nanocomposite is obtained：an increase of 113% in the tensile strength and an increase of 11% in the elongation at break over pure PLCL polymer.The g-TiO2/PLCL nanocomposites with a certain amount of g-TiO2content have better shape memory properties than pure PLCL polymer.The g-TiO2nanoparticles play an additional physical crosslinks which are contributed to improvement of the shape memory properties.展开更多
In oil and gas field, the application of kinetic hydrate inhibitors （KHIs） independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the c...In oil and gas field, the application of kinetic hydrate inhibitors （KHIs） independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly（N-vinyl-2-pyrrolidone-co-2-vinyl pyridine）s （HGs） is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran （THF） hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.展开更多
The living cationic polymerization of 4-[2-(tert-butyldimethylsiloxy)ethyl]styrene (TBDMES) was studied in methylcyclohexane (MeChx)/methylchloride (MeCl) (50/50 V/V) solvent mixture at -80 degrees C. The initiator 1,...The living cationic polymerization of 4-[2-(tert-butyldimethylsiloxy)ethyl]styrene (TBDMES) was studied in methylcyclohexane (MeChx)/methylchloride (MeCl) (50/50 V/V) solvent mixture at -80 degrees C. The initiator 1,1-diphenylethylene (DPE) capped 2-chloro-2,4,4-trimethylpentane (TMPCl) was formed in situ in conjunction with titanium tetrachloride (TiCl(4)). The Lewis acidity of TiCl(4) was decreased by the addition of titanium(IV) isopropoxide (Ti(OiPr)(4)) to accomplish living polymerization of TBDMES. Hydrolysis of poly(TBDMES) in the presence of tetra-butylammonium fluoride yielded poly[4-(2-hydroxyethyl)styrene] (poly(HOES)). FT-IR, NMR and DSC demonstrated the hydrolysis was complete.展开更多
PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline(Ani)with 2-ethyl aniline(EA)at diverse[EA]/[Ani+EA]molar ratios,by employing...PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline(Ani)with 2-ethyl aniline(EA)at diverse[EA]/[Ani+EA]molar ratios,by employing ammonium persulfate as an oxidant.The results revealed that the poly(aniline-co-2-ethyl aniline)(PANI-EA)copolymer micro/nanostructures exhibited satisfactory anticorrosion performance for carbon steel,and the corrosion protection efficiency increased with the increase of water repellent property.Poly(2-ethyl aniline)(PEA)showed the largest contact angle(CA=145°)and show the best corrosion protection for the carbon steel(h=87.29%).It is found that the superior anticorrosion property of PEA is attributed to its high hydrophobicity,low conductivity and low porosity.展开更多
Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical p...Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical polymerization of ethyl 2-bromoacrylate. The obtained comblike polymers were characterized by GPC and 1H NMR.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22172028,21903015,and 22403017)Natural Science Foundation of Fujian Province of China(No.2022J05041)。
文摘Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interface anchoring,and inorganic particles have gained extensive attention recently owing to their large interfacial desorption energy,while their low affinity to bulk components is a drawback.In this study,an interfacial atom transfer radical polymerization(ATRP)technique was employed to grow polystyrene(PS)and poly(2-hydroxyethyl methacrylate)(PHEMA)simultaneously on different hemispheres of Br-functionalized SiO_(2) nanoparticles to stabilize a Pickering emulsion,whereby a brush-type Janus nanoparticle(SiO_(2)@JNP)was developed.The polymer brushes were well-characterized,and the Janus feature was validated by transmission electron microscope(TEM)observation of the sole hemisphere grafting of SiO_(2)-PS as a control sample.SiO_(2)@JNP was demonstrated to be an efficient compatibilizer for a PS/poly(methyl methacrylate)(PMMA)immiscible blend,and the droplet-matrix morphology was significantly refined.The mechanical strength and toughness of the blend were synchronously enhanced at a low content SiO_(2)@JNP optimized~0.9 wt%,with the tensile strength,elongation at break and impact strength increased by 17.7%,26.6%and 19.6%,respectively.This enhancement may be attributed to the entanglements between the grafted polymer brushes and individual components that improve the particle-bulk phase affinity and enforce interfacial adhesion.
基金financially supported by the National Key Research and Development Program of China(no.2022YFC2303100)National Natural Science Foundation of China(nos.T2325010,22305082,52203162,and 22075078)+1 种基金Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism(Shanghai Municipal Education Commission),the Fundamental Research Funds for the Central Universities(nos.JKVD1241029 and JKD01241701)Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry(Changchun Institute of Applied Chemistry,Chinese Academy of Sciences),the Open Project of Engineering Research Center of Dairy Quality and Safety Control Technology(Ministry of Education,no.R202201).
文摘The rising prevalence of drug-resistant Gram-positive pathogens,particularly methicillin-resistant Staphy-lococcus aureus(MRSA)and vancomycin-resistant Enterococci(VRE),poses a substantial clinical challenge.Biofilm-associated infections exacerbate this problem due to their inherent antibiotic resistance and complex structure.Current antibiotic treatments struggle to penetrate biofilms and eradicate persister cells,leading to prolonged antibiotic use and increased resistance.Host defense peptides(HDPs)have shown promise,but their clinical application is limited by factors such as enzymatic degradation and difficulty in largescale preparation.Synthetic HDP mimics,such as poly(2-oxazoline),have emerged as effective alter-natives.Herein,we found that the poly(2-oxazoline),Gly-POX_(20),demonstrated rapid and potent activity against clinically isolated multidrug-resistant Gram-positive strains.Gly-POX_(20) showed greater stability under physiological conditions compared to natural peptides,including resistance to protease degradation.Importantly,Gly-POX_(20) inhibited biofilm formation and eradicated mature biofilm and demonstrated superior in vivo therapeutic efficacy to vancomycin in a MRSA biofilm-associated mouse keratitis model,suggesting its potential as a novel antimicrobial agent against drug-resistant Gram-positive bacteria,especially biofilm-associated infections.
基金National Natural Science Foundation of China(No.50673071,No.50973079)Natural Science Fund for Colleges and Universities in Jiangsu Province,China(No.07KJD540188,No.09KJA540001)
文摘Silk was grafted using 2-hydroxyethyl methacrylate(HEMA)by atom transfer radical polymerization(ATRP)method.The amino groups and hydroxyl groups on the side chains of the silk fibroin was reacted with 2-bromoisobutyryl bromide(BriB-Br)to obtain efficient macroinitiator for ATRP.And the macroinitiator was grafted with HEMA in water aqueous using CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine(PMDETA)as catalyst system.The effects of monomer concentration,the proportion of CuBr and PMDETA,grafting temperature and time on the silk grafting were discussed,and the optimal grafting technology was obtained.FT-IR characterization of the grafted silk showed a peak corresponding to HEMA,which indicated that HEMA was grafted onto the surface of silk.ATRP method could be applied on the silk modification and this technique provided a new way for silk grafting.
基金financially supported by the National High-tech R&D Program of China(863 Program,No.2012AA030313)the Open Project Program of Key Laboratory of Eco-Textiles(Jiangnan University),Ministry of Education,China(No.KLET1115)+1 种基金the Fundamental Research Funds for the Central Universities(No. JUSRP11201)the Cooperative Innovation Fund-Prospective Project of Jiangsu Province,China(No.BY2012060)
文摘This work aimed at effectively utilizing the chemically depolymerized waste poly（ethylene terephthalate）（PET） fibers into useful products for the textile industry.PET fibers were glycolytically degraded by excess ethylene glycol as depolymerizing agent and zinc acetate dihydrate as catalyst.The glycolysis product,bis（2-hydroxyethyl） terephthalate（BHET）,was purified through repeated crystallization to get an average yield above 80%.Then,BHET was nitrated,reduced,and azotized to get diazonium salt.Finally,the produced diazonium salt was coupled with 1-（4-sulfophenyl）-3-methyl-5-pyrazolone to get azo dyestuff.The structures of BHET and azo dyestuff were identified by FT1 R and ^1H NMR spectra and elemental analysis.Nylon filaments dyed by the synthesized azo dyestuff with the dye bath pH from 4.14 to 5.88 showed bright yellow color.The performances of the dyestuff were described with dye uptake,color fastness,K/S,L^＊,a^＊,b^＊.and △E^＊ values.
基金the National Natural Science Foundation of China(No.31000427)the China Postdoctoral Science Foundation(No.20100481214)the Fundamental Research Funds for the Central Universities of China(Nos.2012QN052 and 2012TD013)
文摘This paper describes the fabrication, characterization and properties of a novel hybrid poly（ethylene glycol） （PEG） based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate （APS） and N, N, N/, NCtetramethylethylenediamine （TEMED） as initiators and N, NCmethylene bisacrylamide （BIS） as cross-linker at 60~C. To create a hybrid hydrogel, 0.2% （mass fraction） of MgA1 layered double hydroxide （LDH） was added to the aqueous solution by ultrasonic disper- sion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared （FTIR） spectroscopy, thermal gravimetric analysis （TGA） and scanning electron microscopy （SEM）, while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%--125% with a gel mass fraction of 83%--91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% （based on glycol）. The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.
文摘目的:探究多聚胞嘧啶结合蛋白2[poly(C)-binding protein 2,PCBP2]如何通过调节铁死亡参与大别班达病毒(Dabie Banda virus,DBV)感染后的致病过程及其作用机制。方法:以人单核细胞系THP-1为模型,采用qRT-PCR和Western blot技术检测DBV感染的THP-1细胞中PCBP2的mRNA及蛋白表达水平。通过透射电镜观察病毒感染下的线粒体结构变化,在THP-1细胞中构建了慢病毒介导的PCBP2过表达和敲低稳转细胞系。FerroOrange荧光探针检测Fe^(2+)水平,2,7-二氯荧光素二乙酸酯(2,7-dichlorofluorescein diacetate,DCFH-DA)探针测定活性氧(reactive oxygen species,ROS)水平,Western blot检测铁死亡相关溶质载体家族7成员11(solute carrier family 7 member 11,SLC7A11)和谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)蛋白表达,以评估PCBP2调控对铁死亡的影响。使用铁死亡诱导剂(RSL3、erastin)和抑制剂(Fer-1、Lip-1)处理细胞,qRT-PCR和免疫荧光检测病毒复制水平变化,探索PCBP2是否可以通过调控铁死亡影响DBV复制。结果:在DBV感染的细胞模型中,PCBP2的mRNA和蛋白表达水平显著下调,DBV感染诱导典型铁死亡特征(线粒体嵴减少、肿胀)。通过qRT-PCR和Western blot验证,PCBP2敲低和过表达的THP-1细胞系构建成功,PCBP2敲低下调了铁死亡相关基因SLC7A11和GPX4的表达,导致ROS和Fe^(2+)水平升高;相反,PCBP2过表达使得SLC7A11和GPX4的表达水平升高,ROS和Fe^(2+)的水平降低。半数组织培养感染剂量与蛋白水平的检测进一步证实:铁死亡诱导剂可部分抵消PCBP2过表达促病毒复制的效应,铁死亡抑制剂可部分逆转PCBP2敲低抑制病毒复制的效应。结论:研究发现PCBP2可以通过维持SLC7A11/GPX4系统功能抑制铁死亡,从而限制DBV复制。这不仅阐明了PCBP2在DBV感染中的调控作用,为发热伴血小板减少综合征(severe fever with thrombocytope-nia syndrome,SFTS)的发病机制提供了新见解,同时靶向PCBP2-铁死亡通路可能成为SFTS治疗的潜在策略,为抗病毒药物的研发提供新思路。
基金financially supported by the Program for New Century Excellent Talents in Universitiesthe National Natural Science Foundation of China (Nos. 21074088, 31201426)
文摘Multiarm star block copolymers hyperbranched polyethylenimine-b-poly（2-hydroxyethyl methacrylate） （HPEI-b- PHEMA） with average 28 PHEMA arms have been prepared by atom transfer radical polymerization （ATRP） of HEMA in a mixed solvent of methanol and water using a core-first strategy. The hyperbranched macroinitiator employed was prepared on the basis of well-defined hyperbranched polyethylenimine with Mw/Mn of 1.04 by amidation with 2-bromo-isobutyryl bromide. The polymerization condition was optimized to prepare star copolymers with narrow dispersity, and the variables included the volume ratio of methanol to water, the molar ratio of initiating site to CuC1 and the molar ratio of [CuCl]：[CuBr2]. Under the optimized polymerization condition, the lowest Mw/Mn value of the obtained star copolymers was around 1.3. Kinetic analysis showed that an induction period existed in the polymerization of HEMA. After this induction period, a linear dependence of ln（[M]0/[M]t） on time was observed. The obtained HPEI-b-PHEMA could adsorb hydrophilic molecules. The comparison with the star copolymer with hydrophobic core and hydrophilic PHEMA shell verified that both the hydrophilic core and shell could host the hydrophilic vips, but the amidated HPEI core was more effective than the PHEMA shell.
基金supported by the National Natural Science Foundation of China(22378338,U22A20421)the Project for Science and Technology Plan of Fujian Province of China(2024H4007)。
文摘Poly(ethylene 2,5-furandicarboxylate)(PEF),a bioplastic synthesized via the polymerization of 2,5-furandicarboxylic acid(FDCA)with ethylene glycol,can be served as a substitute to petroleum-based polyethylene terephthalate(PET)due to its enhanced material properties.However,the fabrication of PEF with stable and desirable properties is still a challenge,largely due to the impurities in FDCA.In this study,a highly efficient purification strategy for FDCA was proposed,utilizing a dioxane/H_(2)O binary solvent system for effective crystallization.Furthermore,PEFs were synthesized from FDCA with varying impurity and the effects of these impurities were systematically characterized.The results revealed that impurities in FDCA could result in PEFs with relatively poor thermal properties.This study provides crucial insights for the impact of impurities on PEF properties and FDCA purification.
基金supported by the Applied Basic Research Foundation of Guangdong Province(No.2019A1515110551)the Science Foundation for Distinguished Scholars of Dongguan University of Technology(No.196100041051).
文摘In the context of peaking carbon dioxide emissions and carbon neutrality,development of feasible methods for converting CO_(2)into high value-added chemicals stands out as a hot subject.In this study,P[D+COO^(−)][Br^(−)][DBUH^(+)],a series of novel heterogeneous dual-ionic poly(ionic liquid)s(PILs)were synthesized readily from 2-(dimethylamino)ethyl methacrylate(DMAEMA),bromo-substituted aliphatic acids,organic bases and divinylbenzene(DVB).The structures,compositions and morphologies were characterized or determined by nuclear magnetic resonance(NMR),thermal gravimetric analysis(TGA),infrared spectroscopy(IR),scanning electron microscopes(SEM),and Brunauer-Emmett-Teller analysis(BET),etc.Application of the P[D+COO^(−)][Br^(−)][DBUH^(+)]series as catalysts in converting CO_(2)into cyclic carbonates showed that P[D+COO^(−)][Br^(−)][DBUH^(+)]-2/1/0.6was able to catalyze epiclorohydrin-CO_(2)cycloaddition the most efficiently.This afforded chloropropylene carbonate(CPC)in 98.4%yield with≥99%selectivity in 24 hr under solvent-and additive-free conditions at atmospheric pressure.Reusability experiments showed that recycling of the catalyst 6 times only resulted in a slight decline in the catalytic performance.In addition,it could be used for the synthesis of a variety of differently substituted cyclic carbonates in good to excellent yields.Finally,key catalytic active sites were probed,and a reasonable mechanism was proposed accordingly.In summary,this work poses an efficient strategy for heterogenization of dual-ionic PILs and provides amild and environmentally benign approach to the fixation and utilization of carbon dioxide.
文摘A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The samples obtained from the synthesis were characterized by Fourier Transform-Infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (<sup>1</sup>H NMR), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The results show that the synthesis of the polymers is more feasible under neat conditions rather than solvent directed reaction. Moreover, the DSC data shows that the polystyrene obtained is amorphous in nature and therefore displayed only a glass transition signal rather than crystallization and melting peaks. In addition, this study indicates that homolopolymerization of styrene via free radical polymerization tends to be preferable in less polar solvents like THF than in non-polar solvents like benzene. Benzene might destabilize the formation of the reactive radicals leading to the formation of the products. In summary, the homolpolymerization of styrene is more feasible than the homopolymerization 2-hydroxyethyl methacrylate under the experimental setup used. Styrene is more reactive than 2-hydroxyethyl methacrylate than free radical polymerization reaction due in part of the generation of the benzylic radical intermediate which is more stable leading to the formation of products than alkyl radical which are less stable. Furthermore, polymerization of styrene under neat conditions is preferable in solvent-assisted environments. The choice of solvent for the synthesis of these polymers is crucial and therefore the selection of solvent that leads to the formation of a more stable reaction intermediate is more favorable. It is worth noting that the structure of the proposed copolymer consists of a highly polar and hydrophilic monomer, 2-hydroxyethyl methacrylate and a highly non-polar and hydrophobic monomer, styrene. These functionalities constitute an amphiphilic copolymer with diverse characteristics. A plausible explanation underlying our observations is that the reaction conditions employed in the synthesis of these copolymers might not be the right route required under free radical polymerization.
基金Project(50903023) supported by the National Natural Science Foundation of ChinaProject(HEUCF201210005) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2010RFQXG037) supported by Harbin Special Fund for Innovation Talents of Science and Technology,China
文摘The preparation of TiO2/poly（L-lactide-co-ε-caprolactone）（PLCL） nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone（ε-CL）.The resulting poly（ε-caprolactone）-grafted TiO2（g-TiO2） was characterized by Fourier transform infrared spectroscopy（FTIR）,thermogravimetric analysis（TGA） and transmission electron microscopy（TEM）.The g-TiO2can be uniformly dispersed in chloroform and the g-TiO2/PLCL nanocomposites were successfully fabricated through solvent-casting method.The effects of the content of g-TiO2nanoparticles on tensile properties and shape memory properties were investigated.A significant improvement in the tensile properties of the 5% g-TiO2/PLCL mass fraction nanocomposite is obtained：an increase of 113% in the tensile strength and an increase of 11% in the elongation at break over pure PLCL polymer.The g-TiO2/PLCL nanocomposites with a certain amount of g-TiO2content have better shape memory properties than pure PLCL polymer.The g-TiO2nanoparticles play an additional physical crosslinks which are contributed to improvement of the shape memory properties.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2009CB219504-03)the National Natural Science Foundation of China (Grant No 51106054)the Colleges and Universities High-level Talents Program of Guangdong
文摘In oil and gas field, the application of kinetic hydrate inhibitors （KHIs） independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly（N-vinyl-2-pyrrolidone-co-2-vinyl pyridine）s （HGs） is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran （THF） hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.
基金supported by the Beijing Municipal Project for Developing Advanced Human Resources for Higher Education(Elastomers and Biomaterials).
文摘The living cationic polymerization of 4-[2-(tert-butyldimethylsiloxy)ethyl]styrene (TBDMES) was studied in methylcyclohexane (MeChx)/methylchloride (MeCl) (50/50 V/V) solvent mixture at -80 degrees C. The initiator 1,1-diphenylethylene (DPE) capped 2-chloro-2,4,4-trimethylpentane (TMPCl) was formed in situ in conjunction with titanium tetrachloride (TiCl(4)). The Lewis acidity of TiCl(4) was decreased by the addition of titanium(IV) isopropoxide (Ti(OiPr)(4)) to accomplish living polymerization of TBDMES. Hydrolysis of poly(TBDMES) in the presence of tetra-butylammonium fluoride yielded poly[4-(2-hydroxyethyl)styrene] (poly(HOES)). FT-IR, NMR and DSC demonstrated the hydrolysis was complete.
基金financial supports of the National Natural Science Foundation of China (No. 41476059)the Natural Science Foundation of Hebei Province (No. E2018108011)
文摘PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline(Ani)with 2-ethyl aniline(EA)at diverse[EA]/[Ani+EA]molar ratios,by employing ammonium persulfate as an oxidant.The results revealed that the poly(aniline-co-2-ethyl aniline)(PANI-EA)copolymer micro/nanostructures exhibited satisfactory anticorrosion performance for carbon steel,and the corrosion protection efficiency increased with the increase of water repellent property.Poly(2-ethyl aniline)(PEA)showed the largest contact angle(CA=145°)and show the best corrosion protection for the carbon steel(h=87.29%).It is found that the superior anticorrosion property of PEA is attributed to its high hydrophobicity,low conductivity and low porosity.
文摘Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical polymerization of ethyl 2-bromoacrylate. The obtained comblike polymers were characterized by GPC and 1H NMR.
