最新刊期
卷 ， 期 4 ， 2014
- 摘要：For the first time,a water-swellable rubber,poly(natural rubber-g -acrylamide),was prepared quickly by frontal polymerization.Compared with batch polymerization,the front polymerization process was studied and the polymers were characterized.The frontal polymerization reaction is ignited after the system temperature is higher than 45 ℃ approximately.As important process parameters,the frontal temperature is about 112 ℃ while the front velocity is between 0.3 cmmin-1 and 1.0 cmmin-1.The grafting efficiency of frontal polymerization is 51.8% which is 2.8 times as much as that of batch polymerization.The maximum water absorption of products prepared via FP was calculated as 7.66 gg-1 which is 60% higher than that of the batch polymerization.While the reaction time of frontal polymerization is an eighth of the reaction time of batch polymerization.The microstructure of water-swellable rubber synthesized by frontal polymerization was studied.The relatively uniform hollows,at a size range from 4 m to 10 m,can improve the swelling ability while keep the good strength and elasticity.While the batch polymerization polymers have a lots of holes less than 2 m and sporadic linear holes near 1 mm.关键词：Frontal polymerization;Natural rubber;Water-swellable rubber;Grafting
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发布时间：2021-03-19
Rapid Communications
- 摘要：Polyamide is an important kind of polymer material used as engineering plastics and fibers.It is very important and necessary for polyamide materials to improve their antistatic properties with chemical or physical methods.Polyaniline material is considered as the most promising conductive polymer because of its easily obtained raw material,simple synthesis process,unique doping phenomenon,high conductivity and good stability in air.But polyaniline is difficult to be melted or to dissolve in solution due to its unique molecular chain structure and strong intermolecular force,and that limits its application.Usually polyaniline is used as an antistatic agent in polyamide-polyaniline composites to improve the antistatic property of polyamide fabrics,coatings,oil pipelines and other polyamide products,as well as the processing property of polyaniline.Based on compounding characteristics of different composite systems,the preparation methods,research progress and application areas of polyamide-polyaniline composite fibers,composite films,composite powders and three-phase composite material systems were reviewed.关键词：Polyamide;Polyaniline;Conductive composites;Preparation methods
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发布时间：2021-03-19
Reviews
- 摘要：Amphiphilic dendrigraft -caprolactone copolymers were prepared via the grafting reaction of polyethylene glycol chloroformate on the side and terminal hydroxyl groups of the dendrigraft poly(-caprolactone)s.The copolymers were characterized by 1H-NMR and GPC.1H-NMR analysis revealed that the graft rate was approximately 50%.GPC analysis showed that the molecular weight of the amphiphilic copolymers had a relatively narrow unimodal distribution.Their molecular weights were apparently increased comparing to the raw dendrigraft poly(-caprolactone)s.The amphiphilic copolymers were able to disperse directly in water forming micelles.The diameters of the micelles were measured by DLS to be in the range of 16 to 31 nm with moderate PDI of 0.25 to 0.39.The morphology of the micelles was observed by transmission electron microscopy (TEM).The micelle particles with an irregular globular shape were composed of smaller particles whose size is in accordance with the size of a single polymer molecule.In water,there might be an equilibrium between the unimolecular micelles and assembled multimolecular micelles.The amphiphilic copolymers showed high drug-loading capacity and drug encapsulation rate to hydrophobic antitumor drug pachitaxel,owing to the nano-sized cavities inside the dendrigraft structures.关键词：Dendrigraft polymer;Poly(-caprolactone);Amphiphilic copolymer;Drug carrier
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发布时间：2021-03-19 - 摘要：Negatively-charged DNA and positively-charged polyethylenimine (PEI) were selected to form layer-by-layer self-assembly films on different substrates.The changes of film morphologies and surface roughness during the assembly processes were observed and measured in detail by AFM at a molecule level.The influences of DNA concentration,ion concentration,substrate and modification method on the self-assembly films were analyzed in detail in order to understand the interaction between DNA and PEI.The results show that all the above factors affect the surface morphologies and roughness of the DNA/PEI films.It was found when the DNA/PEI film was self-assembled on mica surface modified by PEI,the increase of surface roughness followed a zigzag pattern with increasing the number of layers.The study may help us understand the molecular mechanism of layer-by-layer self-assembly.关键词：Deoxyribose nucleic acid (DNA);Polyethylenimine (PEI);Layer-by-layer self-assembly;Atomic force microscope (AFM)
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发布时间：2021-03-19 - 摘要：The melting behavior,crystallizing characteristics and tensile properties of biaxially oriented polypropylene (PP homopolymer for BOPP film (h-BOPP) and PP-PE copolymer for BOPP film (c-BOPP)) were investigated by differential scanning calorimetry (DSC),optical microscopy (OM),tensile test and wide angle X-ray diffraction (WAXD).The results showed that compared with h-BOPP,the isotacticity and crystallization rate of c-BOPP were lower,and its half crystallization time was longer at the same crystallization temperature.For h-BOPP and c-BOPP samples without annealing,the elongation at break was higher.However,after annealing at 140 ℃ for 2 h,the elongation at break of both h-BOPP and c-BOPP decreased a lot,as the more perfect crystallites formed.It was believed that crystals of higher perfection had less ability to rearrange themselves under stretching and therefore could not sustain large extensional deformation.Since there are many ethylene segments in the molecular chains that could inhibit the nucleation and crystallization,the crystallization rate of c-BOPP was low,resulting in lower perfect crystallites after annealing.So the elongation at break of c-BOPP was a little more than that of h-BOPP.In addition,the crystalline structure was proven to be partially destroyed under the extensional deformation,and the oriented noncrystalline molecular chains could be easily reorganized into more perfect crystals in the post heating runs.Due to the ethylene segments in the molecular chains of h-BOPP,the oriented noncrystalline molecular chains of h-BOPP could be easier reorganized.This paper explained the mechanism related to the differences between the tensile properties and crystallization behavior of BOPP with different molecular chains.关键词：BOPP;Homopolymer and copolymer;Melting and crystallization;Tensile behavior;Deformation mechanism
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发布时间：2021-03-19 - 摘要：A new kind of organic-inorganic poly(aluminum chloride)-poly(dimethyl diallyl ammonium chloride) (PAC-PDMDAAC) hybrid polymer flocculant was synthesized using ammonium persulfate as initiator,tetrasodium EDTA(Na4EDTA)as the agent and nitrogen as protective agent.The effects of monomer dimethyl diallyl ammonium chloride (DMDAAC) mass fraction,initiator mass fraction,reaction temperature and reaction time on the intrinsic viscosity of hybrid polymers were examined.Results show that the optimum reaction conditions are as follows:the monomer mass fraction 30%,mass fraction of initiator 0.7%,temperature 60 ℃,reaction time 5 h.The hybrid polymer was characterized by Fourier transform infrared spectroscopy (FTIR),thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) methods,and it is implied that the SO42- ion existed at the chain end of PDMDAAC.The hydroxyl aluminum particles with positive charge are bonded with PDMDAAC through SO42- ion.That made PAC and PDMDAAC form a new kind of long chain polymer material.SEM results showed that the hybrid flocculant possessed irregular surface shape and large specific surface area,which made it easier to play the roles as a bridge and adsorption.The distribution of aluminum form in flocculants was studied by Al-Ferron complexation timed spectrophotometric method.Results show that Alc part increases significantly in hybrid flocculant.The PAC,composite PAC-PDMDAAC and hybrid PAC-PDMDAAC were used in humic acid kaolin simulated water samples and Yangtze river water respectively.It is manifested that the hybrid flocculant has advantage of turbidity and UV254 removal rate over the other two.关键词：Organic-inorganic hybrid;Poly aluminum chloride;Dimethyl diallyl ammonium chloride;Flocculants
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发布时间：2021-03-19 - 摘要：Alkali lignin was used as raw material to prepare sulfomethylated alkali lignin (SAL).SAL was then further incubated by horseradish peroxidase (HRP) to obtain the products (HPSAL) with high degree of sulfonation and high molecular weight.The gel permeation chromatography (GPC),infrared spectroscopy (IR),nuclear magnetic resonance (NMR),ultra violet-visible spectrum (UV-Vis) and headspace gas chromatography (HS-GC) were used to investigate the structural characteristics of HPSAL.Compared with SAL,the molecular weight (Mw) and the sulfonation degree of HPSAL increased by above 20-fold and 30% after HRP incubation,respectively.It was also indicated that the carboxyl content increased while the phenolic and methoxyl groups decreased after HRP incubation.HRP incubation could oxidize phenolic group to form phenoxyl radicals.The free electron of the phenoxyl radicals could transfer to the ortho-,para-positions of phenolic groups and C of SAL side chains,inducing the increase of sulfonation reactivity.On the other hand,the increase of sulfonic group content was beneficial to the polymerization of SAL by HRP incubation.The polymerization was achieved by radicals coupling,including -O-4',-',-1' and -5' linkages.The results of molecular simulation indicated that the chances of -O-4' linkage increased significantly due to the decrease of methoxyl content and increase of sulfonic group content.关键词：Horseradish peroxidase;Sulfomethylated alkali lignin;Polymerization;Reactivity
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发布时间：2021-03-19 - 摘要：With a vane extruder,poly(butylenes succinate) (PBS)/lignin biocomposites were prepared.The effects of vane extruder processing temperature (130,135,140,145 ℃) and rotating speed (10,20,30,40 r/min) on residence time,apparent quality and mechanical properties of composites were investigated,as well as the morphology properties with scanning electron microscope (SEM).The results showed that the residence time of materials gradually decreased with the rising of rotating speed,as well as the rising of processing temperature; the apparent quality of composites slightly changed with the rising of processing temperature,but dramatically changed with the rising of rotating speed; the mechanical properties of composites also slightly changed with the rising of processing temperature,but each mechanical property of composites had a different effect of the rising of rotating speed.In addition,the morphology of composites fracture sections slightly changed with different processing temperatures,but significantly changed with processing rotating speed.These results were related to the structural and conveying characteristics of the vane extruder,positive displacement conveying and plastic energy dissipation of materials are generated in elongational flow,which improve the efficiency of mass transfer and strengthen the mechanism of interaction between components of composites.For the performance and economic costs of the PBS/lignin composites,the susgested processing conditions of vane extruder are as follows,the segments temperatures of vane extruder are 115,125,135,125 ℃ and the rotating speed is 20 r/min.关键词：Vane Extruder;PBS;Lignin;Processability;Mechanical performance
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发布时间：2021-03-19 - 摘要：Regenerated cellulose microspheres were prepared by means of electrospraying technology from environmental-friendly NaOH/urea aqueous system.The effects of processing parameters including surface tension,electrostatic force,solution viscosity and flow rate on the morphology and size of cellulose microspheres were investigated.The properties of microspheres were characterized by SEM,FTIR and XRD.The results indicate that microspheres with small particle size were prepared from cellulose solutions with low value of surface tension.The particle size is related to the homogeneity of solution and the volatility of solvent system.There is an obvious decrease in the particle size with an increase in the electrostatic force,while the particle size increases with increasing flow rate.The shape of microspheres depends on solution viscosity significantly.With decreasing solution viscosity,the shape of particles may change from sphere to wedge and even strip.Meanwhile,the particle size decreases and size distribution increases.In addition,the regenerated cellulose microspheres have good porosity.The molecular structure of cellulose remains but the crystal structure changes from cellulose I into cellulose Ⅱ in the process of dissolving and regenerating.关键词：Electrospray;NaOH/urea aqueous system;Cellulose microspheres;Surface tension;Electrostatic force;Solution viscosity
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发布时间：2021-03-19 - 摘要：Based upon 1,1,1-trimethanol propane (TMP) as core and 2,2-bis(hydroxymethyl)propionic acid (DMPA) as branched monomer,the first to the fifth generation of hydroxyl-terminated aliphatic hyperbranched polyesters were synthesized through melt polycondensation.The effect of hydrogen bonding interaction on rheological properties of hydroxyl-terminated hyperbranched polyesters was studied by rotational rheometer.The results showed that the onset of nonlinear viscoelastic region occurred at lower strains for hydroxyl-terminated hyperbranched polyesters of lower generations compared with those of higher generations in the dynamic strain sweep experiments.Relaxation times calculated from dynamic rheological parameters indicated that the lower generations relaxed much slower than their higher generation counterparts.Hydroxyl-terminated hyperbranched polyesters of the first and the second generations showed shear-thinning behavior of pseudoplastic fluid but the third to the fifth generations of hyperbranched polyesters showed Newtonian fluid behavior in both oscillatory and steady shears within the deformation rates investigated.The Cox-Merz rule was found to be not obeyed by all the polymers studied.The degree of crystallinity was higher for low generations compared with high generations detected by temperature sweep experiments.These phenomena appeared in the rheological experiments are closely related to intermolecular hydrogen bonding interaction.关键词：Hyperbranched polyesters;Hydroxyl-terminated;Hydrogen bonding interaction;Rheological property
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发布时间：2021-03-19 - 摘要：In order to avoid the corrosion,pollution,and the serious break of carbon nanotubes (CNTs),Diels-Alder (DA) ［4 + 2］ cycloadditions on the sp2 carbons of CNTs are used for the introduction of functional groups that allow the attachment of potential initiator moieties of ATRP.The multi-walled carbon nanotubes (MWNTs) based initiator of ATRP was synthetized by using a DA reaction between MWNTs and furfuryl-2-bromoisobutyrate obtained via esterification reaction.The MWNTs-initiator (MWNTs-Br) with controlled grafted content by changing the conditions of the DA reaction was used to initiate the polymerization of acrylate-POSS on the MWNT surface.The thickness of acrylate-POSS coated onto MWNTs can be changed by controlling the grafted degree of MWNTs-Br.Finally,a core-shell structure with MWNT at the center was obtained successfully and the thickness of shell can be adjusted from about 5,10,to 15 nm through choosing different initiators.The multifunctional molecules coated MWNTs have better compatibility with other polymer matrix and it provides a potential application for the preparation of composite materials based on CNT chemistry.关键词：Carbon nanotubes;Polyhedral oligomeric silsesquioxane (POSS);Diels-Alder reaction;ATRP reaction
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发布时间：2021-03-19 - 摘要：Dissipative particle dynamics are used to investigate the self-assembly behavior of coil-rod-coil (CRC) triblock copolymers in selective solvents.In coil-selective solvent case,the morphological transitions of CRC solutions are induced by varying the rod length Lr and the coil length Lc.The increase of rod length makes the contact area between rods and solvents larger,and the interface energy enhanced.To reduce the contact area and interface energy,rod blocks tend toward aggregation.With increasing coil length,the coil stretching conformational entropy is increased,which results in the distribution of rod block aggregates more scattered.Two kinds of interesting phase structures (spherical phase and micellar phase) are observed by varying the solvent preference (aCS) and rod length Lr.With the solvent preference aCS varied from coil-selective to neutral and then to rod-selective,the rod-rich-domains in spherical micelle move from the interior to the surface and the number of rod-rich-domain layers is changed.Also,the rod length influences the internal structure of the spherical phase and induces the phase transition between the different spherical phases.The micellar phase includes segmented smectic micelle and rod helices-like micelle,where the rod blocks are arranged in the liquid crystal structure due to the anisotropy of the long rods.关键词：Dissipative particle dynamics;Coil-rod-coil;Selective solvent;Self-assembly;Interface energy
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发布时间：2021-03-19 - 摘要：A novel kind of PAN/CP/PA nanofiltration (NF) composite membranes was fabricated by interfacial polymerization,while piperazine (PIP) was used as aqueous phase monomer and trimesoyl chloride (TMC) was chosen as organic phase monomer to prepare a polypiperazine-amide (PA) barrier layer based on polyacrylonitrile (PAN) nanofibrous substrate modified by carbopol (CP) gel (a bionic adhesive).FTIR results showed that hydrogen bonds were formed between carboxyl groups (COOH) of CP and cyano groups (CN) of PAN,while ionic bonds of carboxylic acid ammonium salt (COO-H2N+) were obtained by neutralization reaction between carboxyl groups of CP and secondary amine groups of PIP.Then interactions of each layer in composite membranes were enhanced.PAN/PA composite membranes and PAN/CP/PA composite membranes were prepared by the same interfacial polymerization process based on PAN and PAN/CP nanofibrous substrates,respectively.Tensile test results indicated that the PAN substrate and PA barrier layer of composite membranes were firmly bonded together by CP gel to form an integrated structure of composite membranes.The resulting tensile strength of composite membranes was increased from 15.1 MPa to 24.2 MPa.Compared with PAN/PA composite membranes,PAN/CP/PA membranes had similar water flux but possessed better rejection rates for different kinds of nitrate salts and MgCl2,which may be attributed to that the PAN/CP/PA composite membrane was strongly negative-charged according to a great amount of carboxyl groups of CP.关键词：Nanofiltration;Composite membrane;Interfacial polymerization;Carbopol;Structure stability
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发布时间：2021-03-19 - 摘要：2,2'-[1,1'-biphenyl］- 4,4'-diylbis(oxy)］bis［6-fluoro-benzonitrile］ monomer was synthesized from 4,4'-biphenol (BP) and 2,6-difluorobenzonitrile (DFBN) through pseudo high dilution,then reacted with the bisphenol-like monomer,4-(4-hydroxyphenyl)-phthlazin-1(2H)-one (DHPZ) to obtain alternate-like copolymer (a-PPEBN) by nucleophilic substitution.Random copolymer (r-PPBEN) was synthesized from BP,DFBN and DHPZ through a one-step procedure.Gel permeation chromatography (GPC) test showed that the two methods could both obtain a high molecular-weight polymer with average number molecular weight of 2.4 104 for r-PPBEN and of 3.4 104 for a-PPEBN.Intrinsic viscosity of a-PPBEN was 0.96 dL/g in chloroform at 25℃ and that of r-PPBEN was 0.94 dL/g.The structure of the monomers and polymers were confirmed by Fourier transform infrared spectroscopy (FTIR),nuclear magnetic resonance (NMR),mass spectrum (MS) and element analysis.The tests showed that the two kinds of copolymer displayed different crystallization properties and thernostability in spite of having the same chemical composition.Thermogravimetric analysis (TGA),differential scanning calorimetry (DSC),dynamic mechanical thermal analysis (DMA) tests demonstrated that a-PPBEN had better thermal stability,higher glass transition temperature (Tg) and storage modulus than r-PPBEN.Tg of a-PPBEN was almost 10 K higher than that of r-PPBEN,suggesting that a-PPBEN possessed more regular rigid structure than r-PPBEN.Spherocrystal patterns of r-PPBEN under polarizing microscope indicated that some micro blocks of PBEN segments were derived from the reaction of BP and DFBN.Wide-angle X-ray diffraction (WAXD) tests also proved the indication.The copolymers all showed good solubility by virtue of introducing twisted,non-coplanar phthalazinone moieties into the backbone of the polymers.At room temperature,the two kinds of copolymers were soluble in a variety of aprotic polar solvents,such as N-methyl-2-pyrrolidinone (NMP),chloroform N,N-dimethylacetamide (DMAc) etc.关键词：Copoly(arylene ether nitrile)s;Alternate copolymer;Random copolymer;Structure;Properties
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发布时间：2021-03-19 - 摘要：In order to improve mechanical properties of the foams made by acrylated epoxidized soybean oil (AESO),AESO was further modified with maleic anhydride (MA) to yield another polymerizable resin (MA-AESO) in this work.Accordingly,more double bonds were attached to triglycerides of the soybean oil.Then,the MA-AESO resin was copolymerized with diluent monomer styrene (St) to produce biodegradable MA-AESO foams.Meanwhile,cell structure and compressive properties of the foams prepared at different ratios of MA-AESO/St and curing conditions were characterized.In addition,biodegradability of the forms was investigated by soil burial test.It was found that the foams had higher compressive property than AESO foams,because the former contained more double bonds in triglycerides of the soybean oil,which increased cross-linking density of the foams.Thus,environmental-friendly foams with mechanical performance comparable to traditional petroleum based stiff unsaturated polyester foam plastics can be obtained even at high proportions of the vegetable oil component.In spite of having high cross-linking density,weight loss due to soil burial biodegradation of MA-AESO foams was higher than that of AESO foams,which may be related to the increased amount of ester groups in MA-AESO molecules.关键词：Epoxidized soybean oil;Modification with maleic anhydride and acrylic acid;Plastic foam;Mechanical properties;Biodegradability
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发布时间：2021-03-19 - 摘要：Polyaniline (PANI) nanostructures with a high conductivity (10-2~10-1 S/cm) were synthesized by template-free method in the presence of different kinds of ferric salts,such as FeCl3,Fe(NO3)3,Fe2(SO4)3,FePO4 as oxidants.The ferric salts,acting as strong acidic salts,will produce protons via hydrolysis,which could be used as dopant for PANI.The nanostructures characterized by FTIR,UV-Visible absorption and XRD spectra are identical to the emeraldine salt state of PANI.This method is more simple and cheap because ferric salts could act as both oxidant and dopant at the same time,resulting in omitting external dopant.Moreover,the resulting nanostructures show thinner diameter and higher crystallinity than those of the nanofiers oxidized by ammonium persulfate (APS) perhaps due to the low redox potential of ferric salts.It is found that the ratios of oxidant to aniline affected strongly the morphology and conductivity of PANI.The counter-anions have some influences on the PANI morphology,however have little effects on the structure and properties of PANI.关键词：Polyaniline;Nanostructures;Ferric salt;Dopant-free;Template-free
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发布时间：2021-03-19 - 摘要：High-infrared emissitivity and high-electrical conductivity polyaniline (PANI) films were prepared by electrochemical deposition of aniline in aqueous solution of camphorsufonated acid (CSA) in the presence of additives such as the inorganic salt or maltodextrin,etc.The roughness and emissivity of PANI films can be adjusted by addition of a suitable additive.When small size inorganic salts like NaCl or LiCl were used as additives,the roughness of PANI films was enhanced accompanied with 0.16~0.26 increase in infrared emissivity.Large size organic molecules such as maltodextrin can significantly enhance the roughness of PANI films,and infrared emissivity can reach 0.84 with an increment of 0.53.The increasing emissivity of PANI films may be attributed to the particular surface morphology,where deep-cave structure exists,accompanied by hill-like and ridge-like patterns.The particular surface morphology of PANI films formed by the maltodextrin molecules with different molecular weight and size was beneficial for the absorption of infrared radiation with different wavelengths,and thereby the emissivity of films increased.Considering that high concentrations of maltodextrin may destroy the intactness of films rendering films fracture and low electrical conductivity,polyacrylic acid was chosen as the second additive.In an electrolyte consisting of 1 mol/L maltodextrin and 0.310-3 mol/L polyacrylic acid,intact PANI film with emissivity of 0.84 and conductivity of up to 109 S/cm can be prepared.关键词：Electrochemical polymerization;Polyaniline;Emissivity;Conductivity;Additive
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发布时间：2021-03-19
Research Article
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