最新刊期
卷 ， 期 10 ， 2014
- 摘要：The strong and tough nacre holds a fine brick motarstructure of an alternate arrangement of inorganic sheets and organic macromolecules.This structure has inspired the design and fabrication of inorganic-organic composite materials for decades.Graphene,with excellent mechanical,electrical,thermal and single atomic layer structure,is the ideal building block for nacre-mimetic materials.Recent progress of graphene-based nacre-mimetic layered materials was highlighted.The main assembling methods are layer by layer assembly,solution casting,filtration and liquid crystal wet-spinning.The main interlayer forces are van der Waals forces,hydrogen bonding,ionic coordination and covalent crosslinking.Graphene-based nacre-mimetic layered materials show much better mechanical properties than nacres.The strength and toughness can reach more than 5 times and 10 times those of nacres,respectively.The composite materials also shows multifunctions,such as electrical conductivity and chemical resistance.关键词：Graphene;Nacre-mimetic;Brick motar;Composite materials;Liquid crystal spinning
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发布时间：2021-03-19 - 摘要：Since the monolayer stability of graphene was reperted,scientists and researchers have never reduced the study enthusiasm with it,especially in the field of polymer composites.Two-dimensional graphene with its incredible performance is considered to be an ideal material to improve polymer materials' performance.Now,graphene is often used to enhance electricity,thermal and mechanical properties of polymers.Compared to other common modified systems,polymer/graphene composites exhibited excellent and comprehensive performance.In this paper,graphene and its polymer matrix composites were introduced and classificed,several main preparation methods of graphene/polymer composite materials and their industrialization application researches were emphasized,at the same time,we reviewed the latest progress in the studies on polymer/graphene composites.关键词：Graphene;Polymeric composites;Industrialization
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发布时间：2021-03-19 - 摘要：Graphene is very popular in recent years,due to its unique electrical,thermal,mechanical,optical and electrochemical properties.With these useful advantages,graphene has been used as a substance to incorporate various kinds of functional materials.Among them,graphene/conducting polymer composites have attracted a great deal of interest owing to their new properties or enhanced performance during the past few years,because conducting polymers have been widely used for electronic,optical and electrochemical applications thanks to their low cost,good environmental stability,interesting electroactivity,high pseudocapacitance and unusual doping/dedoping chemical characters.This review discusses the current development of graphene/conducting polymer composites.After introduction of the properties of graphene and conducting polymers.This review summarizes various methods to synthesize graphene/conducting polymer composites,as well as their enhanced properties.Finally,the applications of graphene/conducting polymer composites,such as supercapacitors,sensing platforms,fuel cells,solar cells,electrochromic devices,lithium ion batteries and so on,are also described.关键词：Graphene/conducting polymer composites;Preparation;Function;Properties;Applications
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发布时间：2021-03-19
Reviews
- 摘要：Nanocomposite hybrid hydrogels (NC-Gels) are a topic of intense interest at present because they combine the advantages of the organic component and the inorganic component into one material.The NC-Gels offer prospects for application in diverse fields including mechanical device,drug delivery,tissue engineering,etc. We have been focusing on constructing NC-Gels with tailored functionalities by controlling over the cross-linking agents,polymer components and hydrogel network structure.A series of NC-Gels were developed with surprising mechanical properties,multiple functionalities and even smart sensitivity.More recently,a facile approach was proposed to fabricate organic cross-linked hydrogels (OC-Gels)and hybrid hydrogels (H-Gels) by using photoactive polystyrene (PS) nanoparticles and functional hybrid particles (H-Gels) as the cross-linking agents,respectively,which provides a platform in building up complex systems for the smart hydrogels.The applications of these hydrogels were also explored in area of the biomedical and smart sensor.关键词：Organic/inorganic hybrid;Nanocomposite hydrogels;High mechanical properties;Functionalities;Multi-responsiveness
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发布时间：2021-03-19
Feature Articles
- 摘要：Polypropylene (PP)/intumescent flame retardant (IFR) filled PP (PPFR) alternating multilayered composites with different layer numbers (2,4,16 and 64) were fabricated through a layer-multiplying coextrusion technology.The influence of the number of layers on the flame-retarding and mechanical properties of the multilayered specimens was investigated.Polarized light micrographs displayed that PP and PPFR layers were distributed alternatively along the thickness direction of the multilayered specimen,and interfaces between PP and PPFR layers were enriched with increasing the number of layers.The non-isothermal crystallization curve of the specimen with more layers tended to become similar to that of the conventional IFR-filled system,which was ascribed to the heterogeneous crystallization of PP layers induced by IFR particles located around interfaces.This suggested that the distribution of IFRs could be controlled by changing the number of layers.The results of vertical burning test,LOI and MCC showed that increasing the number of layers could play a positive role in accelerating the self-extinguishment of an ignited specimen and decreasing its heat release rate.Compared with that of the 2-layer specimen,the LOI of 64-layer specimen was increased from 19.5 to 25.Tensile properties displayed that increasing the number of layers little influenced the tensile strength of multilayered specimens,while induced a significant increase of the elongation at break.It was considered that the multilayered distribution of IFRs could not only promote the formation of continuous char layers,but also retard the propagation of crazes in the whole composites.Thus,it would be a novel route to fabricate polymer composites with both excellent flame retardancy and mechanical properties.关键词：Polypropylene;Flame retardants;Multilayered distribution;Flame retardancy;Mechanical properties
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发布时间：2021-03-19 - 摘要：Poly(1-butene) was modified with rare earth -nucleating agents which were introduced in situ during bulk polymerization of 1-butene.The influence of nucleating agent amount on the molecular weight,melting temperature (Tm),degree of crystallinity (c),and crystallization behavior of resulting poly(1-butene) was investigated in detail by gel permeation chromatography (GPC),differential scanning calorimeter (DSC),polarizing microscopy (POM),and wide angle X-ray diffraction (WAXD).The results show that with the increase of nucleating agent content the isotacticity of poly(1-butene) was slightly increased,the number-average molecular weight (Mn) was obviously improved and the molecular weight distribution was narrowed while the activity of Ziegler-Natta catalyst was somewhat decreased.The addition of rare earth -nucleating agents changed the crystallization behavior of polymers,the spherulite size of nucleated poly(1-butene) dramatically decreased compared with that of pure poly(1-butene) and tends to homogenization with the increasing of nucleating agents content,the c of poly(1-butene) is improved,especially when the addition of -nucleating agents is 300 mg,but dropped dramatically after this point.In addition,the rare earth -nucleating agents not only play an positive role in improving Tm by changing the proportion of forms Ⅰ' and Ⅲ,but also speed up the transformation of crystalline form from Ⅱ to Ⅰ,shorten the crystal transformation period.关键词：Ziegler-Natta catalyst;Poly(1-butene);Rare earth -nucleating agents;Crystallization
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发布时间：2021-03-19 - 摘要：The nanocrystalline Co0.7Cu0.1Zn0.2Fe2O4 ferrites and the polypyrrol(PPy)-Co0.7Cu0.1Zn0.2Fe2O4 nanocomposites were prepared by self-propagating combustion method and an in situ polymerization method,respectively.The structure and morphology of the synthesized materials were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM) and Fourier transform infrared spectrometry (FTIR),and the dielectric,microwave absorbing and magnetic capability of the two materials were studied by wave-guide method and vibrating sample magnetometer (VSM),respectively.The results show that the pure spinel Co0.7Cu0.1Zn0.2Fe2O4 ferrites are obtained and a small amount Co2+ ions of the octahedron ferrites are replaced by Cu2+ ions,which results in the reduce of lattice constant of the Co0.7Cu0.1Zn0.2Fe2O4 ferrites.The two powders both have good dispersity and the average size of the two kinds of particles is about 15 nm and 50 nm,respectively.In the measuring frequency range of 5.0~20.0 GHz,the reflection loss of PPy-Co0.7Cu0.1Zn0.2Fe2O4 composites is between -16.25 and -20.27 dB,and the reflection loss maximum value is about -20.27 dB at 18.0 GHz with a bandwidth of 2.0 GHz (full frequency width at about a half of the peak response),which is obviously higher than that of the Co0.7Cu0.1Zn0.2Fe2O4 ferrites.The saturation magnetization (Ms) and remanent magnetization (Mr) of the PPy-Co0.7Cu0.1Zn0.2Fe2O4 composites are 1.29 emu/g and 0.429 emu/g,respectively,which are smaller than those of the Co0.7Cu0.1Zn0.2Fe2O4 ferrite.But the coercive force (Hc) of the PPy-Co0.7Cu0.1Zn0.2Fe2O4 composites,which is 38.96 KA/m,is greater than that of the Co0.7Cu0.1Zn0.2Fe2O4 ferrite.关键词：Composites;Ferrite;Dielectric properties;Magnetic properties
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发布时间：2021-03-19 - 摘要：Weak polarity solvent aliphatic polyurethane (PU) resins with PBGA as soft segment and IPDI,BDO,IPDA as hard segment were prepared by different organo-metallic catalysts (stannous octoate,dibutyltin dilaurate,MB 20,BiCAT Zn,zirconium acetylacetonate,nickel acetylacetonate,neodymium neodecanoate,cerium neodecanoate).The synthesized aliphatic PU resins were studied by FTIR and GPC.And,the mechanical properties of elastomeric films formed by aliphatic PU resins were tested.In addition,the effects of organo-metallic catalysts on the storage stability of aliphatic PU resins were investigated by storage at high temperature,and the influence mechanism was characterized by FTIR,GPC and 1H-NMR.The researches show that different metal ions had obvious influence on the synthesis and the storage stability of aliphatic PU resins.The significant decreases of viscosity,molecular weight and mechanical properties were caused by the alcoholysis of ester groups of the PU chain during storage at high temperature,especially for the aliphatic PU resins catalyzed by BiCAT Zn and dibutyltin dilaurate.关键词：Organo-metallic catalyst;Weak polarity solvent;Aliphatic polyurethane resin;Storage stability;Alcoholysis
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发布时间：2021-03-19 - 摘要：A hydrophilic block copolymer poly(ethylene glycol)-block-poly(dimethylaminoethyl methacrylate) (PEG-b-PDMAEMA) was prepared via atom transfer radical polymerization (ATRP).Then a further side-chain-grafting of PDMAEMA blocks using a series of monosaccharide through the formation of the quaternary ammonium resulted in the copolymer PEG-b-P(DMAEMA-co-DMAEMA-Sac).The degree of grafting was determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy.Furthermore,the self-assembly behavior of 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (TPPS) with PEG-b-P(DMAEMA-co-DMAEMA-Sac) in pH 1.0 acidic aqueous solution was deeply studied.The ultraviolet-visible spectrum (UV-Vis) indicated that TPPS existed as J-aggregates in the core of PEG-b-P(DMAEMA-co-DMAEMA-Sac)/TPPS complex micelles.Moreover,the supramolecular chirality and its formation mechanism were studied by circular dichroism (CD) and 2D NOESY.It was revealed by CD spectrum that the chiral feature was resulting from asymmetric arrangement of TPPS in the J-aggregates and the signal amplitude increased along with the rise of monosaccharide grafting degree.At the same time,the 2D NOESY spectrum implied weak interaction between TPPS and the grafted monosaccharide.It can figure out that the interaction site of grafted monosaccharide is H-C(4) and H-C(5).Different kinds of monosaccharide were used for contrast tests.It was worth noting that the direction of Cotton spilt signal is associated with the configuration of C(4) and C(5).As a result,the monosaccharide with (4S,5R) configuration led to a positive Cotton signal at 424 nm and a negative one at 490 nm.On the contrary,the monosaccharide with (4R,5R) configuration led to a negative Cotton signal at 424 nm and a positive one at 490 nm.It would be possible that the supramolecular chirality may come from the hydrogen bond interaction between TPPS and hydroxyl on monosaccharide.关键词：Self-assembly;Supramolecular chirality;J-aggregates;Hydrogen bond
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发布时间：2021-03-19 - 摘要：Novel flexible P(VDF-CTFE)/PA11-g-GMA ferroelectric polymer films with high energy density,were prepared via melt extrusion in a twin screw extruder and thermal stretching.The preparation protocol including two steps:(1) as an interface compatilizer,GMA was introduced into nylon11 (PA11) for preparing blended films; (2) based on stretch processing,the s-P(VDF-CTFE)/PA11-g-GMA films were obtained.The crystal configuration and micromorphology of the films were characterized by x-ray powder diffraction (XRD) and scanning electron microscopy (SEM).The electric energy storage and discharge behaviors in the films were studied by electric displacement (D)-electric field (E) loop measurements.It was found that the interface cohesive ability between P(VDF-CTFE) and PA11 was improved because of the strong polar effect of GMA,which is responsible for the increasing of the dipoles and high polarization under the applied fields,clearly observed in the dielectric spectra of the copolymer films.It is also demonstrated that PVDF segments in uniaxially stretched P(VDF-CTFE)/PA11-g-GMA films form large amount of -crystal.That is to say,if the crystalline morphology with a high -crystal content can be further modified to help the discharge process,a polymer capacitor film with high energy densities and low dielectric loss can be achieved.In this paper,the breakdown strength and energy density of the flexible s-P(VDF-CTFE)/PA11-g-GMA films are 275 MV/m and 8.09 J/cm3,respectively.It shows a great potential of a new class of polymer films with high energy density for flexible capacitors.关键词：P(VDF-CTFE);PA11-g-GMA;Copolymer films;High energy density
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发布时间：2021-03-19 - 摘要：A series of (P^N^P)cobalt(Ⅱ) complexes were prepared by the reaction of N-containing diphosphine ligands and anhydrous cobalt dichloride and their catalytic performance in the polymerization of styrene were also investigated.Upon activation with ethylaluminum sesquichloride (EASC),all these cobalt complexes showed high catalytic activities up to 5.44105 g(PS) mol-1(Co) h-1 for the solution polymerization of styrene in toluene.The reaction parameters,such as styrene concentration (2~4 mL),Al/Co molar ratio (20~160),reaction temperature (0~70 ℃) and ligand structure of cobalt complexes were employed in order to study their influences on the polymerization of styrene and the properties of the resulting polymers.The molecular weight,molecular weight distribution and microstructure of the resulting polymers were characterized by GPC and 13C-NMR spectra.The GPC results indicated that all the polystyrenes obtained had low molecular weight (Mn=2000~5900) and narrow molecular weight distribution (1.75~2.05).The 13C-NMR spectra demonstrated that the microstructure of polystyrenes obtained was atactic.关键词：Cobalt complexes;N-containing diphosphine ligands;Styrene;Polymerization
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发布时间：2021-03-19 - 摘要：Herein,the synthesis of an -nlinear-hyperbranched supramolecular block copolymer was reported.First,a linear polymer PMMA-AZO composed of poly(methyl methacrylate) with an azobenzene group at the end was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization.Secondly,a hyperbranched polymer CD-g-HPG composed of hyperbranched polyglycerol with a -cyclodextrin group at the focal point was synthesized by ring-opening multibranching polymerization (ROMBP).Then,the linear PMMA-AZO and hyperbranched CD-g-HPG were conjugated together through the specific CD/AZO host-guest interactions,leading to the formation of amphiphilic linear-hyperbranched supramolecular block copolymer PMMA-b-HPG.The supramolecular polymer of PMMA-b-HPG can be grafted onto gold surface to form self-assembled monolayer through SAu bond generated from the end of trithiocarbonate group,which is introduced into PMMA-AZO by chain transfer agent used in RAFT polymerization.As a result,the modified surface exhibits a hydrophilic feature.When exposed to UV light,however,the hydrophilic CD-g-HPG polymers are dropped off from the surface because of the dissociation of AZO/CD complex,and then the surface turns into hydrophobic.Further immersing the gold surface into CD-g-HPG solution,a hydrophilic surface can be restored.In this way,a modified gold surface which can be tuned reversibly between hydrophilic and hydrophobic under light stimuli was prepared.关键词：Supramolecular block copolymers;Linear-hyperbranched;Host-guest interactions;Surface modification;Hydrophilic-hydrophobic transition
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发布时间：2021-03-19 - 摘要：A photo-rheometer with a UV-cure monitoring accessory was used to measure the gelation time and volume shrinkage of acrylate/liquid crystal syrups during photopolymerization,and the volume shrinkage data were compared with those obtained from density approaches.The experimental results show that gelation times of these syrups are shorter than 10 s and the volume shrinkages are alomost the same via the different test approaches,which implies the photo-rheology (P-Rheology) technique is an accurate and easy method to measure online photopolymerization volume shrinkage of acrylate/liquid crystal systems.Two types of polyhedral oligomeric silsesquioxane (POSS),methacrylisobutyl polyhedral oligomeric silsesquioxane (MI-POSS) and methacryl polyhedral oligomeric silsesquioxane (MA-POSS),were added to acrylate/liquid crystal syrups in order to reduce their volume shrinkage during photopolymerization.P-Rheology and photo-differential scanning calorimetry(P-DSC) were used to investigate the effects of POSS content and type on volume shrinkage and double-bond conversion of acrylate/liquid crystal syrups,respectively.The results indicate that MA-POSS slightly decreases the double-bond conversion while does not bring obvious effect on the volume shrinkage.Adding 10 wt% MA-POSS only declines the photopolymerizion volume shrinkage by 12%.However,MI-POSS does not change the double bond conversion while can reduce markedly the volume shrinkage.The photopolymerizion volume shrinkage of acrylate/liquid crystal syrups is decreased by 29% with adding 10 wt% MI-POSS.关键词：Acrylate/liquid crystal syrups;Polyhedral oligomeric silsesquioxane (POSS);Volume shrinkage;Photopolymerization;Photo-rheology
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发布时间：2021-03-19 - 摘要：The monomer 2-methacrylate-1-methyl pyridine (MAMP) was synthesized by using acryloyl chloride and 2-pyridine methanol.Then,poly(2-methacrylate-1-methyl pyridine) (PMAMP) with different molecular weights was prepared by free radical polymerization of MAMP.PMAMP was further reacted with methyl iodide to give poly(2-methacrylate-1-methyl pyridinium iodide) (PMAMPI) of various cationic degrees.1H-NMR was used to analyze the structure of monomers.The structure of polymer,molecular weight and distribution,cationic degree and heat resistance of PMAMPI were tested using Fourier transform infrared spectroscopy (FTIR),Gel permeation chromatography (GPC),electrical conductivity test,and thermal gravimetric analysis (TG) respectively.The precipitation experiment and mass spectrometry (ESI-MS) tests were performed and it was proven that PMAMPI was hydrolyzed under alkaline conditions.The produced PMAMPI was applied to the salt-free reactive dyeing of cotton fabrics by cold pad batch method to achieve better dyeing properties.The influence of molecular weight and cationic degree of polymers on dyeing performance was studied.The results showed that the influence of molecular weight on color yields was diminished within the testing range due to the broad molecular weight distribution.The deepest color yield of dyed fabric was found at 35% of cationic degree of the polymer.The color yields and colorfastness properties (wash fastness,rubbing fastness and light fastness) of dyed fabrics by using cold pad batch salt-free dyeing method with PMAMPI pretreatment of cotton fabrics were closed to,or even better than,those using conventional salt dyeing method.There was no significant difference in the resulting breaking strength,moisture permeability and air permeability between the salt dyeing method and the studied salt-free dyeing method.It is concluded that the PMAMPI can be used as a salt-free auxiliary in reactive dyeing on cotton fabrics.关键词：Cationic polymer;Synthesis;Characterization;Cationic degree;Reactive dyes;Salt-free dyeing
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发布时间：2021-03-19 - 摘要：Six half-sandwich rare earth catalysts Cp'LnR2(THF)n (Cp'=C5H5,C5Me4SiMe3; R=CH2C6H4NMe2-o,CH2SiMe3; Ln=Sc,Y,Lu; n=0 or 1) have been synthesized for polymerization of butadiene activated with [Ph3C]B(C6F5)4] in toluene.The polymerization activity,stereoselectivity,catalyst efficiency,molecular weight and molecular weight distribution have been studied with these catalysts.The obtained polybutadiene was characterized by 1H-NMR,13C-NMR,FTIR,GPC and DSC.The results revealed that catalyst (C5H5)Sc(CH2C6H4NMe2-o)2 shown the highest activity (up to 9600 kg-polymer/mol-Sc h),better catalyst efficiency (45%),high cis-1,4 selectivity (cis-1,4 content 96%) and narrow molecular weight distribution (PDI ca. 1.3).The polymerization activity was high when the polymerization was carried out in toluene or chlorobenzene and decreased with the polymerization temperature reduction.Solvents and polymerization temperature have no obviously effects on the structure of polybutadiene.When the [Bd]/[Sc] molar ratio ranged from 500 to 3000,the molecular weight of polybutadiene has increased linearly (up to 44.6104) with the constant low molecular weight distribution.The results indicated that the molecular weight and molecular weight distribution of polybutadiene could be well controlled.The glass transition temperature of polybutadiene was -107 ℃,and there are also two distinct peaks at -63 ℃ and -8 ℃ shown in DSC curves at a heating/cooling rate of 10 K/min,corresponding to the cold crystallization and melting behavior of polybutadiene.关键词：Rare earth catalyst;Scandium;High cis-1;4 polybutadiene;Butadiene
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发布时间：2021-03-19 - 摘要：Amorphous calcium phosphate (ACP) has excellent biocompatibility,osteoconduction and biodegradability.However,as it can be transformed easily to a more thermal stable phase,i.e.HAP,ACP shows poor stability in solution.As a soluble and biocompatible additive,regenerated silk fibroin (RSF) can mediate the growth of inorganic crystals.If the RSF is capable of inducing and stabilizing of the ACP,it will be desirable to expand its application to the field of bone repair.The pH value of the mineralization solution increased slowly when the ammonia gas diffused into the solution,leading to the precipitation of calcium phosphate.The morphology and polymorph of calcium phosphates were characterized by SEM,TEM,SAED,XRD and FTIR.Generally,the spherical particles were ACP and the aggregated sheets were HAP in our work.The results also showed that ACP could be obtained by adjusting the mineralization time,the weight concentration of RSF,the molar concentrations of calcium ion and phosphate ion.When the RSF and Ca2+/PO43- concentrations were fixed to 0.5% and 2 mmol/L,respectively,only ACP could be obtained after 1 h; however,both ACP and HAP could be produced when the duration of mineralization was increased to 3 h.Moreover,all the ACP would be transformed to HAP when the time was increased to 24 h.On the other side,when the Ca2+/PO43- concentrations increased,a higher RSF concentration would be needed to induce the growth of ACP.For example,ACP could be produced under a certain condition that the mineralization time and the RSF concentration were 1 h and 1% respectively,supplemental with 3 mmol/L Ca2+/PO43- concentrations,but ACP couldnt be obtained at any concentration of RSF when the ion concentration was reached to 5 mmol/L.Furthermore,it was found that RSF with higher molecular weight could induce the growth of ACP in a lower concentration under the same condition.The stable ACP/RSF hybrid may have the great potential in the bone repairing.关键词：Amorphous calcium phosphate;Silk fibroin;Biomineralization
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发布时间：2021-03-19
Research Article
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