最新刊期
卷 ， 期 5 ， 2016
- 摘要：Recently,the development of green and recyclable oil-sorbents with high efficiency attracted considerable attentions from domestic and foreign scholars.Cellulose-based aerogels combine the large specific area and high porosity characteristics of aerogel-type materials with natural and renewable advantages of cellulose.After surface hydrophobic treatment,cellulose-based aerogels are very promising environmentally friendly oil-sorbents.In this work,research progress in the regenerated cellulose based aerogel-type oil sorbents,natural cellulose based aerogel-type ones,and bacterial cellulose based aerogel-type ones were systematically reviewed,respectively.Their preparation methods and oil-sorption performance were summarized.The existing problems in the cellulose based aerogel-type oil sorbents' studies and the perspectives in their future research directions were also discussed.关键词：Regenerated cellulose;Nanocellulose;Aerogels;Hydrophobization;Oil-sorbents
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发布时间：2021-03-19
Reviews
- 摘要：The effect of structure and constituent of side groups on unperturbed dimension and polarity is investigated for typical vinyl-polymers,including poly(methyl vinyl ketone)s (PVMK),poly(tert-butyl vinyl ketone) (PTBVK),poly(itaconate) (PI) and 1,2-polybutadiene(1,2-PBD) with various large substituents.Based the unified expressions of primary quantities deduced by an improved method of configurational- conformational statistics,the characteristic ratios of mean-square radius of gyration of atactic PVMK,PI,PTBVK and 1,2-PBD are obtained to be 3.09,2.96,1.72 and 1.11,respectively,and the characteristic ratios of mean-square dipole moments of atactic PI,PVMK and PTBVK are 1.57,0.79 and 0.45,respectively.From comparing the intrinsic viscosity,the characteristic ratios,the temperature coefficient and the differential values of conformational energies,it is found that the dependence of physical properties of PVMK on the configuration and chain length is changeable obviously.From contrasting the characteristic curves of PI and PTBVK,it is observed that there are quite characteristic differences between mean-square dipole moment and mean-square radius of gyration,the difference of their differential values of energies for PTBVK chain is reached to 20.1210-2 mol/J for instance.However,the characteristic curves of PI and 1,2-PBD are smooth relatively,it is explained that their side groups,even with different structures,have similar physical effects.Therefore,it suggests that the comparative study of chain feature based on the relevant structure model of side groups is necessary.关键词：Poly(methyl vinyl ketone)s;Poly(tert-butyl vinyl ketone);Poly(itaconate);Characteristic ratios;Temperature coefficient;Intrinsic viscosity
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发布时间：2021-03-19 - 摘要：Cylindrical polymer brushes with densely grafted cyclic side-chains are synthesized via the grafting-onto method.The structure and composition of the polymers are well characterized.Linear polynorbornylene derivative (l-PND) backbones containing alkynyl groups are prepared by ring opening metathesis polymerization (ROMP),and cyclic poly(tert-butyl acrylate) side-chains (c-PtBA) containing azide groups are synthesized by the combination of atom transfer radical polymerization (ATRP) and copper catalyzed azide-alkyne cycloaddition (CuAAC) reaction.Then,the cyclic side-chains are grafted densely onto the backbone by CuAAC reaction to form a cylindrical polymer brush.The structures of the polymers were characterized by 1H-NMR,gel permeation chromatography (GPC) and infrared (IR) spectroscopy.The obtained polymer brush has a long backbone of 400 degree of polymerization.The densely grafted side-chains lead to extension of the backbone.A single molecule of the polymer brush shows a wormlike (cylindrical) morphology observed by the atomic force microscopy (AFM).The length of the polymer brush is 200 nm,and the diameter is 30 nm.The polymer brush with cyclic side-chains is observed as a wormlike molecule for the first time,which has great reference value to study the influence of the topological structure (backbone and side-chains) on the morphology of the polymer brushes.关键词：Controlled polymerization;CuAAC;Cyclic polymer;Cylindrical polymer brush
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发布时间：2021-03-19 - 摘要：In order to gain proton exchange membranes with high proton conductivity and stability,a series of side-chain type sulfonated fluorinated poly(aryl ether) copolymers (sSPFAEs) are prepared by attaching di-sulfonated naphthanoyl pendants to the fluoro-containing poly(aryl ether) backbone,subsequently solution cast into sSPFAE membranes and characterized.The obtained membranes with ion exchange capacity of 1.42~2.03 mmol/g are transparent and ductile,exhibiting Young's modulus higher than 1.0 GPa and elongations at break of 66%~105%.Water absorbing and swelling behavior tests indicate that the obtained sSPFAE membranes have rather low water uptakes and good dimensional stability.In the testing temperature range of 30~90℃,their water uptakes are about 21%~51% while the swelling ratios less than 7%.They also show considerably good thermal and oxidative stability,the weight losses are no more than 5% at 320~360℃ in TGA tests and below 2% after the Fenton's tests at 80℃ for 1 h,respectively.Moreover,the obtained sSPFAE membranes have fairly high proton conductivity,for example,the proton conductivity reaches 217 mS/cm at 80℃ for the membrane of sSPFAE-0.8 (IEC=2.03 mmol/g).关键词：Fuel cell;Proton exchange membrane;Sulfonated poly(aryl ether);Fluorinated polymers;Side-chain sulfonation
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发布时间：2021-03-19 - 摘要：With hydroxyl multi-walled carbon nanotubes(MWCNTs-OH) as carbonous fillers the high performance PVDF hollow fiber ultrafiltration membranes modified by MWCNTs-OH were prepared by the nonsolvent induced phase inversion process.Adding MWCNTs-OH into N,N-dimethyl acetamide (DMAC) solvent with ultrasonic treatment could strengthen their dispersion,and produce uniform casting membrane solution.The morphology and performances of modified membranes were characterized by scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD),dynamic contact angle (DCA) and mechanical properties tests.The effects of MWCNTs-OH on the water flux and rejection as well as mechanical properties of the resulted hollow fiber membranes were investigated.The results showed that the water flux increased from 376.4 L/m2h to 510.9 L/m2h,while the rejection stabilized around 95.0% as the MWCNTs-OH loading increased from 0 to 0.09 wt%.The tensile strength and elongation at break increased from 1.68 to 2.42 MPa and 44.18% to 79.18%,respectively.The SEM and TEM images indicated that MWCNTs-OH were easy to reunite in the matrix along with the increase of contents of MWCNTs over 0.09 wt%,resulting in the decrease of the membrane tensile strength and water flux.The crystal form of the hollow fiber membranes changed little with the addition of MWCNTs-OH which was evidenced by the analysis of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction.关键词：PVDF;Hydroxyl multi-walled carbon nanotubes (MWCNTs-OH);Hollow fiber;Ultrafiltration membranes
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发布时间：2021-03-19 - 摘要：Sustainable rosin polymer grafted cellulose copolymers (cellulose-g-PMAEDA) were prepared by ATRP using microcrystalline cellulose as raw material in homogeneous media.In particular,the microcrystalline cellulose was transformed into 2-bromoisobutyryl-functionalizaed cellulose in LiCl/DMAc homogeneous media,subsequently,the renewable and hydrophobic monomer,(2-methacryloyloxy)ethyl ester of dehydroabietic acid (MAEDA),was used for the ATRP polymerization of side chains of the amphiphilic cellulose-g-PMAEDA under the catalysis system of CuBr/PMDETA.Kinetic studies indicated the polymerization process was controlled and living.The successful formation of copolymers was confirmed by Fourier transform infrared spectroscopy (FTIR),1H nuclear magnetic resonance (1H-NMR),gel permeation chromatography (GPC) and X-Ray diffraction (XRD).Owing to the introduction of PMAEDA side chains,the cellulose-g-PMAEDA graft copolymers showed enhanced thermal stability which was confirmed by thermal gravity analysis (TGA).The UV absorption spectrograph and water contact angle measurement were employed to investigate the UV absorption ability and hydrophobicity of the prepared cellulose-g-PMAEDA graft copolymers.The results showed that the attachment of rosin based polymer side chains imparted the excellent UV absorption ability and good hydrophobicity to the cellulose-g-PMAEDA graft copolymers.The self-assembly behavior of the cellulose-g-PMAEDA graft copolymers was also studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM).The DLS results showed that the cellulose-g-PMAEDA graft copolymers could form micelles with Z-average size of 200 nm and PDI of 0.195; the TEM results further illustrated that cellulose-g-PMAEDA graft copolymers could form spherical micelles with the core-shell structure and the diameters of micelles were around 200 nm,which could be used in drug delivery.关键词：Cellulose;Dehydroabietic acid;Amphiphilic;Atom transfer radical polymerization
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发布时间：2021-03-19 - 摘要：An (aniline oligomer-b-polyethylene glycol)3 star-shaped rod-coil block copolymer was designed,in which aniline oligomer possesses electrochromic property and polyethylene glycol (PEG) has ion conductive property.This star-shaped rod-coil block copolymer could be used in electrochromic devices,which would be much more compatible and processable compared with traditional electrochromic devices fabricated by polyaniline and PEG separately.Three synthetic strategies,that is,oxidative coupling strategy A,arm-first condensation strategy B,and core-first condensation strategy C,were designed to obtain (aniline oligomer-b-PEG)3 star-shaped rod-coil block copolymer.All related products prepared by the three strategies were characterized using FTIR,1H-NMR and MALDI-MS.The advantage and disadvantage of strategies A and B were discussed as well.And it was found that strategy C was a simple and efficient method for synthesizing the ideal (aniline oligomer-b-PEG)3 star-shaped rod-coil block copolymer.In strategy C,trimesoyl chloride was firstly reacted with amino/carboxyl-capped tetraaniline via an acylation reaction to give mono-dispersed star-shaped intermediate M03,which was then reacted with poly(ethylene glycol methyl ether) via polycondensation to give (tetraaniline-b-PEG)3 star-shaped rod-coil block copolymer (S03).The results suggested that ideal (tetraaniline-b-PEG)3 product was synthesized successfully based on the synthetic strategy C.关键词：Aniline oligomer;Polyethylene glycol;Star-shaped block copolymer;Synthesis and characterization
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发布时间：2021-03-19 - 摘要：Thermally conductive composites based on Al2O3-filled poly(butylene terephthalate)/bisphenol-A polycarbonate (PBT/PC) blends were prepared with a melting mix technique by use of twin screw extruding.Triphenylphosphite (TPPi) as an inhibitor was used to suppress the transesterification between PBT and PC.The transesterification,thermally conductive property,phase structure,crystallization parameters and mechanical properties of the materials were characterized by Fourier transform infrared spectroscopy (FTIR),laserflash thermal analysis,scanning electron microscopy (SEM),differential scanning calorimetry (DSC) and mechanical properties tester,respectively.Experimental results show that TPPi can effectively suppress the transesterification; by this,the phase structure of the blend changed and the distribution of the fillers was also influenced.With 1.0 wt% of TPPi loading in PBT/PC (1/1),the co-continuous phase structure formed and the thermal conductivity of the blend improved effectively.After adding 60 wt% of Al2O3 filler in the blend system with 1.0 wt% TPPi,the thermal conductivity of the composite reached to 0.89 W/(mK),which improved by 13% than that of the system with no TPPi.关键词：Thermal conductivity;Polybutylene terephthalate (PBT);Bisphenol-A polycarbonate(PC);Transesterification
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发布时间：2021-03-19 - 摘要：A series of modified poly(vinyl chloride) (PVC) with n-octadecanethiol,denoted as PVCS18,have been prepared through a nucleophilic substitution reaction,where the different substitution degrees (DS) are realized.The structure,phase change properties and thermal stability of PVCS18 comb-like polymers are systematically characterized by Fourier transform infrared spectroscopy (FTIR),hydrogen nuclear magnetic resonance spectroscopy (1H-NMR),differential scanning calorimertry (DSC),thermogravimetric analysis (TG) and wide-angle X-ray diffraction (WAXD).The results demonstrate that the DS has a big influence on the structure and properties of PVCS18 comb-like polymers.With increasing the DS of C18 alkyl side chains,PVCS18 exhibits an interesting variation for phase transition and thermal performance,contributed from the grafted C18 side chains along PVC backbones.With DS increasing from 8.5% to 50.2%,the phase transition temperature changed from 61.7℃ to 66.3℃,the melting enthalpy increased from 5.3 kJ/mol to 50.9 kJ/mol,and the crystallizable number of carbon atoms also increased from 1.4 to 13.8,accompanied with the enhanced crystallinity of C18 alkyl side chains.The chemical junction between the main-chain and side-chains has an important effect on the crystallizable number of carbon atom per side chain,and the smaller the polarity and size of chemical junction,the higher the crystallization ability of side alkyl group is.In addition,PVCS18 comb-like polymer shows a similar thermals stability with that of pristine PVC,demonstrating that the incorporated alkyl side chains do not alter the thermal stability of PVC,showing a promising application perspective.关键词：Comb-like polymer;Side alkyl chains;Poly(vinyl chloride);Crystallization
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发布时间：2021-03-19 - 摘要：The hydrophobic association and polyelectrolyte effect of hydrophobically associated water-soluble polymers (HAWSP) were eliminated in solvents containing 50%(volume percent concentration)1,3-propylene glycol,0.2 mol/L NaCl and water that could make molecules of HAWSP disperse in dilute solutions.Then the polymers of different molecular weights were split through the microporous membrane equipment with different aperture microporous membranes according to the principle of membrane aperture separation.The cumulative percentage of each fraction was calculated through the quantity of each fraction polymer solution which was measured by the curve of percolate quantity-filtration time fitted with a quadratic equation,and the concentration of each fraction polymer solution was measured by spectrophotometry.The Mark-Houwink equation[]=0.182M0.586 of HAWSP which was used to accurately determine the molecular weight of each HAWSP fraction,was calibrated through the static light scattering and capillary tube viscosity methods.The molecular weight distribution curve was determined according to the molecular weight (M) and cumulative percentage (W) of each fraction by using the 4-parameter equation curve.The method of microporous membrane grading to determine the molecular weight distribution of HAWSP was compared with the method of dynamic light scattering for measurement of particle size,the results of the two methods were consistent with each other.关键词：Hydrophobically associated water-soluble polymers;Molecular weight distribution;Molecular weight;4-Parameter equation;Microporous membrane
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发布时间：2021-03-19 -
Simultaneous Synthesis of Poly(ethylene succinate) and Dimethyl Carbonate Using Zn-MOFs as Catalysts
摘要：Three Zn-MOFs have been synthesized via solvothermal and direct mixing methods separately,and then the Zn-MOFs were used as catalysts for the synthesis of poly(ethylene succinate)(PES) and dimethyl carbonate (DMC) by the coupling reaction of ethylene carbonate (EC) and dimethyl succinate (DMSu).The Zn-MOFs were characterized using a variety of different techniques,including X-ray powder diffraction (XRD),scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FTIR),atomic emission spectrophotometry (AES) and others,PES was characterized by FTIR and 1H-NMR.The results showed that the Zn-MOF-L had the best catalytic activity.The MOF-5 and ZnO particles present in the MOF-L-300 contribute to the overall catalytic activity.The optimum conditions of the reaction were as follows:the reaction time,reaction temperature,n(EC)/n(DMSu) and the catalyst dosage were 4 h,215℃,2 and 1 wt% (N2 protection),respectively,in the standard atmosphere pre-polymerization step.The reaction time,reaction pressure and reaction temperature were 2 h, 300 Pa and 220℃, respectively,in the vacuum condensation step.Under these conditions,the yield of DMC was 65.08%,the intrinsic viscosity[] of PES was 0.572 dL/g,the Mn of PES was 21000 and the polydispersity index of PES was 2.21.关键词：Metal organic Frameworks;Ethylene carbonate;Dimethyl succinate;Dimethyl Carbonate;Poly(ethylene succinate)- 67
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发布时间：2021-03-19 - 摘要：A series of homopolymers and copolymers,based on 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and tertbutyl acrylate (tBA),were synthesized by atom transfer radical polymerization (ATRP) using CuBr/(N,N,N',N,N-Pentamethyldiethylenetriamine) (PMDETA) as a catalyst system and 2-bromo ethyl isobutyrate (EBiB) as an initiator in a first step.The homopolymer of MEO2MA exhibited the lower critical solution temperature (LCST) at around 28℃.In a second step,the tert-butyl groups of tBA were hydrolysed with trifluoroacetic acid to form the corresponging block copolymers of MEO2MA and acrylic acid (AA) (PMEO2MA-b-PAA),which exhibited both temperature and pH responsive behaviour.Transmittance (500 nm) measurements were used to obtain the cloud point (CP) of PMEO2MA and PMEO2MA-b-PAA.The CP of PMEO2MA-b-PAA aqueous solution (1 mg/mL) was raised from 26.0℃ to 31.1℃,when the pH value of solutions was increased from 2 to 12.At 28℃,the transformation pH value of PMEO2MA-b-PAA aqueous solutions (1 mg/mL) was around 6.When the concentration increased,the CP decreased.Stimulus-responsive polymer modified silk was obtained through condensation reaction between the amino groups on silk surface and the carboxyl groups of PMEO2MA-b-PAA.Contact angle and moisture regain measurements indicated that the modified silk exhibited both temperature and pH-responsive behaviour.When the pH value of modified silk surface is 2,the conformation of modified silk changed at around 28℃.When the pH value is 6,the transition temperature increased to about 32℃.Smart silk textiles with temperature and pH responsive behaviour could be obtained by a simple and costless process.关键词：Temperature sensitivity;pH sensitivity;ATRP;LCST;Smart textile
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发布时间：2021-03-19 - 摘要：The reptation processes of polymer chains embedded in post arrays are studied by using Monte Carlo algorithm.The simulation results show that the post array with small array spacing can suppress the contour length fluctuation of the polymer chains efficiently so that the relaxation times of the polymer chains coincide with the scaling law given by the reptation theory.However,it can be shown that the reptation in post arrays is slightly different from that in polymer melt by comparing the end-to-end correlation function obtained in simulation with the prediction of reptation theory.The end-to-end correlation functions are underestimated by the reptation theory since the original tube regime can not be fully eliminated by the motion of chain ends in post arrays.The reptation process in post arrays can be perfectly described by the two-dimensional self-avoiding lattice model proposed in this paper.关键词：Polymer chain;Reptation;Post array
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发布时间：2021-03-19 - 摘要：An amphiphilic random copolypeptide,poly(-benzyl-L-glutamate-co-N-(2-hydroxyethyl)-L-glutamine](PBHG),was modified from hydrophobic poly(-benzyl-L-glutamate)(PBLG) to improve hydrophilicity and applied to electrospin into ultrafine fibers.The molecular structure was confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (1H-NMR).The effects of solvent type and PBHG concentration on the properties of spinning solutions were investigated by measuring surface tension,viscosity and conductivity of the solutions.The morphologies of electrospun fibers were observed by scanning electron microscope.The hydrophilicity and cell proliferation ability of PBHG electrospun fibrous mats were also evaluated by water immersion and MTT assay,respectively.It was found that PBHG takes rigid -helix conformation and tends to self-orientate in trichloromethane (TCM) and tetrahydrofuran (THF) from which micron or submicron fibers could be electrospun.The fibers electrospun from PBHG/TCM solutions have poor quality due to large surface tension,high viscosity and low conductivity of the solutions,whereas those obtained from PBHG/THF solutions have smooth surface and homogeneous diameter.In trifluoroacetic acid (TFA),PBHG molecules take random coil conformation and physically entangle with each other.The low surface tension,low viscosity and high conductivity of PBHG/TFA solutions are beneficial for electrispinning nano-fibers,but the low volatility of TFA leads to fiber adhesion.It can be alleviated by using TFA/TCM binary mixtures with suitable TFA content as solvent.PBHG electrospun fibers proved to be more hydrophilic than that of PBLG,and could maintain the skeleton in the water without further crosslinking.MTT results confirmed that PBHG fibers are non-cytotoxic and can promote the cell proliferation.关键词：Electrospinning;Poly(-benzyl-L-glutamate);Poly[N-(2-hydroxyethyl)-L-glutamine];Solution property;Conformation
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发布时间：2021-03-19 - 摘要：This work provides a novel approach to improve the separation performance of PVDF membranes.Poly(vinylidene fluoride)-graft-poly(methyl methacrylate) (PVDF-g-PMMA) copolymers were synthesized via grafting methyl methacrylate (MMA) onto PVDF.Benzoyl peroxide (BPO) was the initiator,and the PVDF was initially modified by tetraethyl ammonium hydroxide (TEAH) in the liquid phase.The copolymer was cast into a flat membrane via immersion phase inversion.The structure and performance of as-prepared membranes were characterized by FTIR,SEM and filtration experiments.Simultaneously,the effects of the concentration of TEAH and the modifying time on surface contact angle were examined.The results indicate that the PVDF formed C C double bonds following dehydrofluorination by TEAH.MMA was grafted onto the modified PVDF backbones,forming a homogeneous pore distribution in the interior and exterior of the membrane.The water contact angle of PVDF-g-PMMA membranes decreased with increasing the TEAH concentration and modifying time.The hydrophilicity of the modified PVDF was the best with 2.0 wt% of TEAH solution at 50℃ for 20 min,under these conditions the grafting degree of membrane was 27.1%,the porosity and mean pore size were 71.6% and 78.9 nm,respectively; the contact angle was 55.9 and decreased to 0 within 50 s; the water flux increased to 665.34 L/(m2h) and the rejection ratio and flux recovery ratio were up to 95.6% and 90.1%,respectively.The separation performance of the PVDF-g-PMMA membrane was significant improvement compared to that of the pure PVDF membrane.关键词：Oil/water separation membrane;Poly(vinylidene fluoride);Bulk modification;Tetraethyl ammonium hydroxide;Methyl methacrylate
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发布时间：2021-03-19 - 摘要：A series of new diblock copolymers bearing rigid liquid crystal cholesterol grafts denoted as PHEMAChol-b-PBLG were designed and sucessfully prepared via a combination of reversible addition-fragmentation chain transfer polymerization (RAFT),ring opening polymerization (ROP) and click chemistry,and their molecular structures were further characterized by NMR,FTIR,GPC and static light scattering (SLS).Then,liquid crystal (LC) phase structures and their transitions as well as thermal stabilities were characterized by differential scanning calorimetry (DSC),polarized optical microscopy (POM) and thermo gravimetric analysis (TGA),and secondary structures of the PBLG blocks were analyzed by FTIR,X-ray diffraction (XRD) and solid-state 13C CP/MAS NMR techniques.Moreover,their secondary molecular structures in THF were analyzed by circular dichroism spectrum (CD),and self-aggregate morphologies in THF/DMF mixed solution were investigated by transmission electron microscopy (TEM).The results demonstrated predominant -helix secondary structures of PBLG blocks for the resulted PHEMAChol-b-PBLG in solid state,and the longer PBLG blocks led to more well-defined -helix structures,and PBLG secondary structures in solution could be tuned by their block lengths and the TFA volume fraction.关键词：Diblock copolymer;Cholesteryl mesogen;Poly(benzyl glutamate);Secondary structure;Self-assembly
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发布时间：2021-03-19
Research Article
- 摘要：To investigate the influence of the branch structure of four-arm poly(L-lactide) (4A-PLLA) on the crystallization behavior of linear poly(L-lactide) (linear PLLA),a series of non-isothermal programs were carried out on a differential scanning calorimeter (DSC) and a polarized light microscope (PLM) equipped with a hot stage.The samples were heated to 200℃/180℃/170℃/160℃ to obtain totally-melting and partially-melting status.According to PLM images after cooling to room temperature,it was proved that the branch structure of 4A-PLLA could promote the crystallization at a cooling rate of 10 K/min when the content of 4A-PLLA exceeded 3 wt% after totally-melting at 180℃ and higher.On the other hand,partially-melting 4A-PLLA and linear PLLA could both act as the nucleating agents in the aforementioned cooling program after melting at 170℃ and lower to promote the crystallization of the blends.Partially-melting samples displayed stronger crystallization and weaker cold crystallization in the cooling and the 2nd heating programs,while the PLM images illustrated more crystalline regions with smaller size for blends with higher 4A-PLLA contents after cooling to the room temperature.The second heating curves of samples showed higher high-melting temperatures as 4A-PLLA contents increased,which was attributed to the crystallization perfection effect of 4A-PLLA and its proportion rising in the crystals of the 4A-PLLA/linear PLLA blends.关键词：Four-armed poly(L-lactide)(4A-PLLA);Branch;Crystallization;Nucleation
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发布时间：2021-03-19
Research Bulletin
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