最新刊期
卷 ， 期 9 ， 2014
- 摘要：Recently,glucose-responsive polymeric materials have attracted great interest for their potential applications in diabetes diagnosis and therapy.Among them,phenylboronic acid (PBA) based polymers hold advantages such as high stability and reversible response as they are totally synthetic materials.This article reviewed the advances of PBA-based polymeric materials for self-regulated insulin delivery and continuous glucose monitoring.Self-regulated insulin delivery systems mainly include glucose-responsive micro/nanogels,polymeric micelles and vesicles.Their component and morphology have great effect on the glucose sensibility,repeated on-off release and insulin encapsulation.On the other hand,PBA-based systems for continuous glucose monitoring contain fluorescent sensors and colorimetric sensors.Since these polymeric materials are gradually optimized,they would show more potential for further practical applications.关键词：Phenylboronic acid;Glucose-responsive;Polymer;Insulin delivery;Glucose monitoring
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发布时间：2021-03-19 - 摘要：Dewetting process of polymer films is a hot research and application field in surface and interface science.Hole-growing dynamics is an important part of the dewetting dynamics,further research on it not only can contribute to our understanding of the dewetting process,but also provide theoretical guidance for the design of polymer patterned surfaces and interfaces.The richness of the properties about the hole-growing dynamics has been the subject of extensive theoretical,experimental and simulation studies and lots of great progresses have been made in recent years.In this paper,our central work is focused on three main problems,including reviewing these most important works,elucidating the difference between theoretical predictions and experimental or simulation results,and proposing the corresponding problems.关键词：Polymer thin films;Hole-growing dynamics;Dewetting;Nucleation and growth
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发布时间：2021-03-19 - 摘要：Polypeptides and their hybrid copolymers have aroused much attention in biomedical fields due to their excellent biocompatibility and biodegradability.N-Carboxyanhydrides (NCA) can be polymerized into polypeptides and their hybrid copolymers via ring-opening polymerization with high efficiency and high yield.Also,polymers synthesized by this method have controlled chain length and molecular weight distribution.In this review,we have summarized the mechanism of NCA ring-opening polymerization,the methods for synthesizing NCA monomers,syntheses of polypeptides and polypeptide-based copolymers,and their applications in hydrogel, membranes, adhesives, antimicrobial vesicles and self-assembly,etc.We also highlight the solution behaviors of polypeptide-based copolymers which can form many functional nanostructures such as antibacterial polymer vesicles for anticancer drug delivery.Finally,we put forward the perspective on the research of polypeptide and polypeptide hybrids.关键词：Amino acid;N-Carboxyanhydrides;Ring-opening polymerization;Vesicles;Self-assembly
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发布时间：2021-03-19
Reviews
- 摘要：The pressure-volume-temperature(P-V-T) properties of natural rubber(NR) composites with different antioxidants were studied.The parameters of Tait equation was calculated and compared with experiments.The results showed that the P-V-T relationship calculated by Tait equation agreed well with the observation results,the residual means between theoretical calculation and experimental values were all less than 0.01 which indicated that the Tait equation can be used to describe the P-V-T relationship of the natural rubber composites.Thermal expansion coefficients () and isothermal compressibility () of nature rubber were evaluated by Tait equations.It's showed that decreases with the increase of pressure,but nearly doesn't change with temperature increasing. will decrease when pressure becomes high and increases with the increase of temperature.This is well explained by molecular simulation that high temperature or low pressure will lead to an expansion on free volume of the system,so that the activity of the molecular chain is enhanced.When there is only one kind of antioxidant in the composites,the values of both and are large,but when these antioxidants are used together,the values of both and are small,and the composite has the best size stability.Furthermore,the cohesive energy density (CED) obtained from molecular simulation shows that the intermolecular interaction force of nature rubber with two kinds of antioxidants is high,so it is hard for or to change.Through accurate description of the changes of and with different pressures and temperatures for the composites,a method with the function of guiding processing and application research was attempted.关键词：Natural rubber;Antioxidants;P-V-T properties;Thermal expansion coefficients;Isothermal compressibility;Molecular dynamic simulation
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发布时间：2021-03-19 - 摘要：Polyisoprene (PI) with high 3,4-structure content (78.76%) was synthesized by anionic polymerization using n-BuLi as the initiator and tetrahydrofuran/cyclohexane as the mixed solvent.P-complex was also introduced into the system to improve the controllability of the polymerization.The molecular structure was characterized by 1H-NMR.Results indicated that when n-BuLi was used as the initiator,the polymerization rate and molecular structure of the products were determined by the channel space between the ion pairs.When the channel space was compatible with the requirement for inserting of the monomers,the polymerization rate would be maximum.The channel space required for 3,4 polymerization of isoprene is the smallest.P-complex with same lithium atom as initiator and large steric hindrance can adjust the channel space between the cation-anion pairs.P-complex can partially block the channel space.Therefore,the introduction of a small dosage of P-complex could not only accelerate 3,4 polymerization,inhibit 1,2 and 1,4 polymerization effectively,but also increase the content of 3,4-PI.On the contrary, with the increase of the temperature,the channel space expanded,resulting in the decrease of 3,4-PI content and the increase of 1,4-PI content.The higher the temperature was,the more content of trans-1,4-PI would be.关键词：Anionic polymerization;Isoprene;Polymerization mechanism;Microstructure
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发布时间：2021-03-19 - 摘要：Poly(ether ether ketone) (PEEK) was synthesized by the aromatic nucleophilic polycondensation reaction of 4,4'-difluorobenzophenone,bisphenol A and 2-methylhydroquinone.Double-arm PEEK macroinitiator containing isopropyl bromide end groups was obtained by bromination with NBS,hydroxylation with dimethylol propionate sodium and esterification reaction with bromo-2-methylpropionyl bromide.Comb-like PEEK-g-DMAEMA (poly(2-(dimethylamino) ethyl methacrylate)) was successfully synthesized via atom transfer radical polymerization (ATRP) using double-arm PEEK as the macroinitiator.The membranes of PEEK-g-DMAEMA were prepared by solution cast.The mixture solvent of water and NMP was used to design the membrane morphology.The structure and morphology of PEEK-g-DMAEMA membranes were characterized by FTIR,1H-NMR,TG and scanning electron microscopy (SEM).The synthesized PEEK-g-DMAEMA is found to improve hydrophilic/hydrophobic phase separation.The weight loss of PEEK-g-DMAEMA membranes occurs at 230 ℃ due to tertiary amine group decomposition.IR results showed that new absorption band at 1728 cm-1 was assigned to the stretching vibration of carbonyl (C=O) groups.The band at 2770 cm-1 was ascribed to the NC stretching of tertiary amino groups linkage compared to original PEEK.With the increase in the DMAEMA grafting degree,the ion exchange capacity (IEC) and water content increase from 1.49 to 2.07 mmolg-1 and 46.91% to 84.19%,respectively.The OH- permeability of copolymer membranes enhances with the increase of IEC,reaching a value of 0.15 mol/L at 2 h.They display reasonably high OH- permeability due to the abundant DMAEMA side chains and the large interchain space,which is available for water occupation.关键词：Atom transfer radical polymerization;Poly(ether ether ketone);2-(Dimethylamino) ethyl methacrylate;Anion exchange membrane
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发布时间：2021-03-19 - 摘要：The cyclopolymerization of non-conjugated ,-dienes such as 1,4-pentadiene,1,5-hexadiene,1,6-heptadiene,1,7-octadiene and 1,9-decadiene and their copolymerization with ethylene by scandium complex [(C5Me4SiMe3)Sc(CH2C6H4NMe2-o)2/[Ph3C]B(C6F5)4]] have been examined.Polymerization conditions and the structure of non-conjugated ,-dienes have an important influence on the catalytic activity and selectivity,polymer products molecular weight and molecular weight distribution. Except for 1,9-decadiene homopolymer which is an insoluble cross-linked polymer,the homopolymerization of 1,5-hexadiene,1,6-heptadiene,and 1,7-octadiene has been achieved to affords soluble cyclopolymers materials.Under the optimum conditions,the homopolymerization of 1,5-hexadiene affords cyclopolymers containing methylene-1,3-cyclopentane (MCPN,83%) units and 3-vinyltetramethylene (VTM,17%) units.In the case of 1,6-heptadiene homopolymerization,a soluble cyclopolyolefin containing both six-member ring methylene-1,3-cyclohexane (MCHX,91%) units and five-member ring ethylene-1,2-cyclopentane (ECPN,9%) units is obtained.However,the homopolymerization of 1,7-octadiene afford a homopolymer containing seven-member ring methylene-1,3-cycloheptane (MCHP,57%) units and non-cyclic pendent double bond units (HEB,43%).By use of this scandium catalyst,the copolymerization of non-conjugated ,-dienes such as 1,5-hexadiene,1,6-heptadiene,1,7-octadiene and 1,9-decadiene with ethylene (1.01105 Pa) has also been achieved to afford relatively high molecular weight novel cyclocopolymer materials that contain polyethylene units,cyclic structure units or non-cyclic pendent double bond units.In the same copolymerization conditions,1,5-hexadiene and 1,6-heptadiene polymerization form cyclic structure units,while the 1,7-octadiene and 1,9-decadiene polymerization form non-cyclic pendent double bond units.The incorporation of 1,5-hexadiene or 1,6-heptadiene in the corresponding copolymer is higher than that of 1,7-octadiene or 1,9-decadiene.关键词：Scandium;Non-conjugated Dienes;Ethylene;Polymerization
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发布时间：2021-03-19 - 摘要：Bacterial cellulose (BC) nanogel-supported polyaniline (PANI) conducting polymer composite gel-membranes with different water contents have been synthesized via in situ polymerization of aniline onto bacterial cellulose scaffold.Preparation conditions such as water content and reaction time,were systematically employed to achieve high conductivity.The effects of water content and reaction time on the composites' properties were intensively studied.The resultant high water content bacterial cellulose/polyaniline (HBC/PANI) and low water content bacterial cellulose/polyaniline (LBC/PANI) composite gel-membranes were fully characterized in terms of structure and morphology.The morphology of HBC/PANI and LBC/PANI composite gel-membranes was observed using a field-emission gun scanning electron microscope (FE-SEM),which demonstrated the PANI were polymerized in the network of BC.Four-probe conductivity tests showed that the best reaction time was 90 min,and samples with low water contents exhibited conductivity as high as 1.7210-2 S/cm,which increased by 57.8% compared to that of HBC/PANI,but complete drying displayed poor conductivity.Alternating-current (AC) impedance measurements proved that ionic conductivity of BC/PANI composites with lower water content was improved.The ionic conductivity of HBC/PANI is 1.4410-4 S/cm and that of LBC/PANI is 1.4910-4 S/cm.The mechanical property tests indicated the obtained BC/PANI composites possessed good mechanical properties,with tensile strength of 0.21 MPa.Besides,low water content could remain good mechanical property.Furthermore,the growth mechanism of BC/PANI composite gel-membranes may be interpreted as first aniline dispersion onto BC nano-fiber network with the hydrochloric acid,and secondly in situ polymerization of aniline with oxidant ammonium persulfate (APS).关键词：Bacterial cellulose;Polyaniline;Water content;Conductivity;AC impedance;Mechanical property
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发布时间：2021-03-19 - 摘要：A coaxial tri-capillary electrospray and template removal method was proposed to produce nanosized core-shell particles for encapsulating of proteins.Polyethylene glycol (PEG) and poly(D,L-lactide-co-glycolide) (PLGA) were used as corona and shell materials,while Bovine serum albumin (BSA),as a model protein,was entrapped in the core.Microparticles with smooth surfaces and distinct core-shell-corona structures were obtained by coaxial tri-capillary electrospray and nanoparticles with diameter about 100 nm were achieved by removing the corona PEG template from core-shell-corona microparticles.Moreover,the nanoparticle size could be modulated by adjusting the feed rate of shell fluid,and the diameter of nanoparticles could be reduced to (688) nm when the shell fluid feed rate was decreased to 0.5 mL/h.The drug loading content and entrapment efficiency of BSA were 3.7% and 78.3%,respectively.It was also found that BSA released from nanoparticles in a typical bi-phased release profile and the process may last for 60 h.The second order structure of BSA released from particles was monitored with circular dichroism spectrum.The results showed that the electrospray process didn't affect the second order structure of proteins,implying that the denaturation of the protein didn't occur during the process of electrospraying encapsulation.关键词：Coaxial electrospray;Nanoparticle;Core-shell;Protein;Drug delivery
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发布时间：2021-03-19 - 摘要：To apply polyaniline thin films in electrochromic devices and optimize their performance,sulfuric acid(H2SO4) and sulfosalicylic acid(SSA) co-doped electrochromic films based on polyaniline were prepared by potentiostatic method on flexible PET-ITO films.The physical properties of the films were studied by scanning electron microscopy(SEM),infrared emissivity tester,FTIR spectroscopy,four-probe meter and UV-Vis spectrophotometer.The influences of electrolyte concentration ratio and temperature on the performance of PANI films were particularly discussed.To study the infrared emission characteristics of polyanline thin films and find key factors for emissivity changing in deposition process,resistance-emissivity curves (R-E curves) were given and their relationship with emissivity variability was discussed.Based on emissivity variance,electrochromic performance in visible lights were observed.R-E curves confirmed that the relationship between infrared emissivity and resistance follows logarithmic function depending on the effective thickness of the films and the conducting structure of the polymer,which can strongly affect the emissivity variability of polyaniline thin films.With the increase of original emissivity (E0),the variability E first increased,and reached the highest value when E0 was 0.71.After that E reduced.The results of UV-Vis spectra confirmed that the films could realize good emissivity variability and at the same time get high contrast of visible lights (T%) between coloring and bleaching.When E0 is 0.71,the T% at average of visible light wavelength is 43.8%.关键词：Polyaniline;Electrochromism;Infrared emissivity;Electrochemical polymerization
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发布时间：2021-03-19 - 摘要：To further explore the high-performance magnetic materials,poly[bis(ethoxycarboxy)methyl acrylate] and its three complexes PEOCMA-Ni2+,PEOCMA-Nd3+,PEOCMA-Gd3+ were synthesized using diethyl bromomalonate as the basic raw material.The synthesis of poly[bis(ethoxycarboxy)methyl acrylate] and its three complexes PEOCMA-Ni2+,PEOCMA-Nd3+,PEOCMA-Gd3+ were described.These polymer-metal complexes were first prepared by the reaction of PEOCMA with Ni2+,Nd3+ and Gd3+.Their structures were determined by FTIR,1H-NMR and GPC,while their metal contents were measured by IPC.The temperature dependence of magnetization at an applied field 3.98106 A/m and the applied field dependence of magnetization at 5 K for the PEOCMA-Mn+ complexes were measured by PPMS(physical property measurement system).The saturation values of magnetization of PEOCMA-Ni2+,PEOCMA-Nd3+ and PEOCMA-Gd3+were 13.2 Am2/kg,9.5 Am2/kg and 38.2 Am2/kg,and the coercive force values of the complexes were 9634 A/m and 1544 A/m,respectively.These results showed the presence of the three kinds of polymer-metal complex magnetic interactions at a low temperature.The magnetic properties of polymer-metal complexes had a great relationship with the type of metal.It was found that although the content of Nd3+ in the complex was higher than that of Gd3+,its saturation magnetization was lower with its inferior magnetic property.关键词：Polymer-metal complex;Bis(ethoxycarboxy)methyl acrylate;Magnetic material
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发布时间：2021-03-19 - 摘要：A novel kind of composite membranes for oil/water separation were prepared via the combination of polypropylene non-woven meshes and superhydrophilic CaCO3-based mineral layer inspired by biomineralization.Poly(acrylic acid) brushes,which are negatively charged and can induce nucleation of CaCO3,were first tethered on the fiber surface of polypropylene non-woven meshes by UV-induced graft polymerization.The mineral layer was then fabricated on the mesh surface by an alternative soaking process.Results from measurements of static and dynamic oil contact angles reveal that the rigid mineral layer traps abundant water and forms a stable oil-repellent interface,which endows the membranes with underwater superoleophobicity (CA150) and low oil-adhesion (SA5) for various kinds of oils.Moreover,the mineral-coated meshes exhibit low transmembrane pressure for water (gravity-driven filtration) and relatively high critical oil breakthrough pressure (10 kPa) due to the unique multiple interconnected pores and overall high porosity of the non-woven structure.Model oil-in-water emulsion filtration experiments further show that the mineralized meshes have high rejection rate towards oil droplets whose particle sizes are larger than 2 m,thus making these composite non-woven meshes promising in the treatment of some industrial oil/water mixtures.关键词：Polypropylene non-woven mesh;Biomimetic mineralization;Calcium carbonate;Underwater superoleophobicity;Oil/water separation
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发布时间：2021-03-19 - 摘要：In this study,the stereocomplex micelles derived from nonlinear poly(ethylene glycol)-polylactide (PEG-PLA) enantiomeric copolymers were designed and prepared for drug delivery.First,the 4-armed PEG-PLA enantiomeric copolymers were synthesized through the ring-opening polymerization of D-lactide (DLA) and L-lactide (LLA) with 4-armed PEG as macroinitiator and stannous octoate as catalyst.4-Armed PEG-b-PDLA micelle(PDM),4-armed PEG-b-PLLA micelle(PLM) and 4-armed PEG-b-PDLA/4-armed PEG-b-PLLA stereocomplex micelle (SCM) were prepared through nanoprecipitation,and the morphologies,sizes and stereocomplex mechanisms of micelles were systemically characterized.It was found that the SCM showed more compact structure,smallert dynamic diameter and critical micellization concentration in contrast to PDM and PLM.Doxorubicin (DOX),a model antitumor drug,was loaded into micelles,and SCM exhibited the best drug loading capability compared with PDM and PLM.In addition,the DOX-loaded 4-armed PEG-PLA micelles,especially SCM,showed more efficient and durable capabilities for malignant cellular proliferation inhibition (e.g.,HepG2 cells,a human hepatoma cell line),and exhibited less toxicities toward normal cells(e.g.,L929 cells,a mouse fibroblast cell line),which revealed the great prospect of SCM for potential antitumor drug delivery.关键词：Malignancy therapy;Controlled release;Stereocomplex micelle;Polylactide;Nanoprecipitation
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发布时间：2021-03-19 - 摘要：Polyglycolide (PGA),poly(L-lactide) (PLLA) and poly(L-lactide-co-glycolide)(PLGA) were prepared by bulk ring-opening polymerization at high temperature and high vacuum using stannous octoate as catalyst and 1,4-butanediol as initiator.The chemical structures of the polymers were characterized by infrared spectroscopy (IR) and H nuclear magnetic resonance (1H-NMR),and their properties were studied by gel permeation chromatography (GPC),differential scanning calorimetry (DSC),thermo gravimetric analysis (TGA),X-ray diffraction (XRD) and rheometry.The results of GPC showed that PLGA and PLLA had high molecular weight and narrow molecular weight distribution.The results of TGA showed that PGA,PLLA and PLGA had high thermal stability and the decomposition temperature increased slowly with increasing units of PGA in PLGA.PGA directly obtained with bulk polymerization was not dissolved in various organic solvents,while the solubility of PGA in hexafluoroisopropanol (HFIP) increased obviously after recrystallization from dimethyl sulfoxide (DMSO).PGA and PLLA had higher crystallinity while PLGA was amorphous,PGA crystallized from DMSO had lower crystallinity.The melts of PGA,PLLA and PLGA were shear-thinning fluids,while PGA and PLLA had higher storage modulus and PLGA had higher loss modulus.Amorphous PLGA was much more easily purified and processed than PGA and PLLA having higher crystallinity,thus PLGA was more suitable to be used as biodegradable material.关键词：Polyglycolide;Poly(L-lactide);Poly(L-lactide-co-glycolide);Ring-opening polymerization;Properties
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发布时间：2021-03-19 - 摘要：The influences of hydroxyl groups on the compactness of lignin adsorption layer and the mechanism were studied when lignin was adsorbed on the solid-liquid interface.By the acetylized modification of alkali lignin (AL),the acetylized alkali lignin (ACAL) was obtained,of which the quantity of hydroxyl groups got a significant reduction from 1.80 to 0.06 mmol/g.The compactness differences between the AL and ACAL monolayer adsorption films on the gold in solution conditions were studied by the quartz crystal microbalance with dissipation (QCM-D),and the differences of the multilayer adsorption films built up with poly-(diallydimethyl ammoniumchloride) (PDAC) in dryness condition were studied by the combination of UV-Vis spectroscopy (UV) and atomic force microscopy (AFM).Both the monolayer and multilayer adsorption results show that the hydroxyl groups can reduce the compactness of the lignin adsorption layer.The infrared spectroscopy (IR) shows that the main aromatic peak of AL shifts to lower wave numbers in ACAL,which provides direct evidence for the enhancement of - interactions between the aromatic nucleus.It can be explained that the existence of the hydroxyl groups goes against the coplanar formation of the aromatic nucleus in lignin.The reduction of the hydroxyl groups can enhance the coplanarity of the aromatic nucleus,which makes a contribution to the increase of the compactness of lignin adsorption layers.关键词：Lignin;Hydroxyl group;Adsorption layer;Compactness
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发布时间：2021-03-19 - 摘要：The organic montmorillonite (OMMT) modified urea-formaldehyde (UF) resin adhesives were prepared by base-acid-base synthetical technology and adding OMMT to the different stage of the synthesis.The technical characteristics of adhesives were tested.The structure of the sample was characterized by X-ray diffraction,infrared spectroscope and scanning electron microscope.The thermal property was measured by thermogravimetric analysis.The results indicated that with the addition of OMMT,the free formaldehyde content in adhesives decreased and the bonding strength increased.And the OMMT added had obviously decreasing aldehyde effect at the first stage and obviously reinforcing effect at the second stage.The SEM results indicated that the sheet structure of the OMMT in the modified adhesive showed a curled shape due to the matrix covered or squeezed.The XRD results indicated that the crystallinity of OMMT/UF adhesives was lower than that of UF adhesives,which suggested that the arrangement regularity of the carbonyl and amino groups in UF resin adhesives was destroyed because of the introduction of the OMMT.The FTIR results indicated that there were a lot of free urea and low content of free formaldehyde in the modified UF resin adhesive.The TG results indicated that the TG curve of the modified resin adhesive moved to higher temperatures,and the thermal decomposition temperature increased.关键词：Urea-formaldehyde;Organic montmorillonite;Preparation;Structure
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发布时间：2021-03-19 -
Molecular Dynamics Investigation of the Compression and Stretching of Polymer Nano-composite Systems
摘要：The tensile,compressive and equilibrium-state properties of polymer nano-composites (PNC) are studied using molecular dynamics (MD) with coarse-grained polymer-nanoparticle model.The influence of the size and the mass loading of the nanoparticles on PNC's mechanical properties,and the microscopic change of the cross-linked networks of PNC systems are investigated by the tensile and the compression tests of the PNC MD simulations.We find that nanoparticles of relatively smaller size reinforce the mechanical property more,when the surface area or the mass loading of nanoparticles of different sizes are kept still.Secondly,the mechanical property of PNC system increases while the increment becomes smaller,as the mass loading of nanoparticles increases; and there exists an optimised value of the mass loading of nanoparticles for enhancing the tensile property of PNC system.Most important,the microscopic polymer-polymer and polymer-NP cross-linked networks existing in PNC systems compete with each other,and affect the tensile and compression stress with different microscopic mechanisms.Additionally,the equilibration-state MD simulations of varying mass loading of nanoparticles illustrate that the ratio of respective microscopic cross-linked networks determines the mechanical properties of PNC systems,and the aggregation of the nanoparticles induced by overloading weakens such effects.关键词：Polymer nano-composites;Mechanical property;Molecular dynamics;Microscopic cross-linked network- 30
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发布时间：2021-03-19
Research Article
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