最新刊期
卷 36 ， 期 6 ， 2016
- 摘要：Dynamic 3D structures are capable of reversible shape morphing upon the application of external stimuli.Once formed,those structures are hard to be reconfigured.Moreover,their maintenance and low temperature resistance act as another two unaddressed but practical issues.Recently,those challenges are tackled by dispersing carbon nanotubes into liquid crystalline vitrimers.Various dynamic 3D structures can be made by just shining light on the polymer films of nanocomposites in minutes.Those structures can be easily reconfigured,repaired and can be used with an extremely low ambient temperature (e.g. -130℃).关键词：Three dimensional dynamic structure;Vitrimer;Liquid crystalline elastomer;Infrared light irradiation
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发布时间：2021-03-19
Research Highlights
- 摘要：Viscoelastic properties of entangled polymer fluids have been an important research area in polymer science and engineering.Unlike elastic solids or simple viscous liquids,entangled polymer fluids exhibit very complicated viscoelastic behavior in an external field,which indicates that the stress is a function of the whole deformation history rather than just of strain amplitude or of strain rate.In the recent half century,plenty of models and theories have been made to understand these viscoelastic properties.Some are based on the principles of continuum mechanics,such as the Maxwell model,the Voigt-Kelvin model,and the various constitutive models,all of which have parameters that are constant in space and time.An alternative model of polymer dynamics and rheology is modeled by a transient network where the entangled points are considered to act as temporary crosslinks and polymer chains are represented by beads and springs.The rheological behavior of the system depends on the kinetics of breakage and reformation of the network made of interacting polymer molecules.Others are microscopic theories for an entangled polymer fluids.One of the most famous and successful molecular theories is the tube theory.In this review article,we first introduce the basic concepts of the linear response of viscoelasticity and the Boltzmann's superposition principle.Then,we focused on the three classical phenomenological models,including the Maxwell model,the Voigt-Kelvin model,and the transient network model,which are still popularly employed in the field of entangled polymers and other viscoelastic materials.In particular,the detailed derivation and critical issues for these models are discussed.Microscopic theories of viscoelasticity will be detailedly and thoroughly introduced in other reviews.关键词：Viscoelasticity;Maxwell model;Voigt-Kelvin model;Transient network model;Boltzmann superposition principle
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发布时间：2021-03-19 - 摘要：Radiation grafting technique has become one of the important methods for modification of polymers. Compared with traditional chemical grafting method, radiation grafting technique has been widely applied in preparation of adsorption materials recently, due to its advantages of easy operation, easy control and without limitation of substrate and monomeretc. The adsorption materials with monomers distributing on the substrate surface prepared by radiation grafting technique, have the advantage of low dosage of monomer, low cost, fast adsorption/desorption rate, high utilization rate of functional groups and good selectivity. This review presented the latest research progress on the application of radiation grafting technique in preparation of selective adsorption materials in recent years, including their synthesis and applications of different pollutants such as heavy metals, radioactive nuclides, semi-metals, non-metals, rare earth metals, precious metals and dyes. The further development in this field is also predicated.关键词：Trunk polymer;Radiation grafting;Adsorption material;Grafting monomer;Functional group
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发布时间：2021-03-19
Reviews
- 摘要：N,N-Di-hydroxyethyl amine-3-propionic acid methyl ester was prepared in a nitrogen atmosphere.And SiO2-HBP-L was in situ synthesized by grafting from with the monomers and α-caprolactone.The structure and morphology were characterized by FTIR,XPS and TG analysis.The results show that the hyperbranched polyester is successfully grafted at the surface of nano-SiO2.Compared with the nano-SiO2,the SEM shows that the dispersion and compatibility of SiO2-HBP-L in the ethanol and rubber matrix is better.Then SiO2-HBP-L/SBR composites were prepared by using the direct mixing method.Vulcanization performance tests show that the curing time(T90) of the composites are much shorter and the composites' total crosslinking density is increased with respect to SiO2/SBR composites.When the composites with 30 phr SiO2-HBP-L,the T90 was reduced to 3.30 min.What is more,SiO2-HBP-L/SBR composites have a great improvement of mechanical properties and wear resistance.It shows that the tensile strength,elongation at break,tear strength and wear resistance of the composites are increasing with the increase of contents of SiO2-HBP-L.The tensile strength,elongation at break of the composites with 30 phr SiO2-HBP-L were 14.8 MPa and 22.2 kN/m2,and its wear resistance decreased to 289.4 mm3.Nano-SiO2 modified with long-subchain hyperbranched polyester (SiO2-HBP-L) was used in the preparation of SiO2-HBP-L/SBR composites.The results show that the performance of SiO2-HBP-L is better than that of nano-SiO2in the reinforcement of SBR.关键词：Nano-SiO2;Hyperbranched polyester;SiO2-HBP-L;SBR;Properties
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发布时间：2021-03-19 - 摘要：The acidified fullerene (C60) was doped into the polyaniline as a conducting dopant,then the poly-(L-lactic acid)/polyaniline/C60 (PLA/PANI/C60) was prepared by the method of emulsion polymerization-blending.The structure and properties of PLA/PANI/C60 were characterized.The PLA/PANI/C60 fiber films and fiber tubes were fabricated by the electrospinning-weaving technology.The morphology,hydrophilicity and electrical properties of PLA/PANI/C60 fibers were studied.The result indicated that the resistivity of PLA/PANI/C60 films reached to the grade of 104 Ω·cm,which was a semiconductor.An electrical stimulation device outputting the square pulse wave signals was designed and assembled according to the principle of the 555 Timer to be used for electrically stimulating the osteoblast cells on the PLA/PANI/C60fiber mats.The PLA/PANI/C60 fiber tube had stable shape and increasing hydrophilicity,so the PLA/PANI/C60fiber mat enhanced the adhesion,growth and proliferation of the osteoblast cells under the stimulation of 18 μA/1 Hz/500 ms signals when it was applied to be the electrical stimulation location material and the host matrix for the cell culture.C60 could promote the chain growth of aniline oligomers during the emulsion polymerization,and improve the polymerization degree of polyaniline.The PLA/PANI/C60 had the decreasing content of aniline oligomers and less poisonous effect on the osteoblast cells during the electrically stimulating.The appropriate electrical stimulation could enhance the differentiation of the growth factor to osteoblast and promote the growth and reproduction of osteoblasts with the PLA/PANI/C60 mats as the concentrating electrical stimulation material.关键词：Polyaniline;Poly (L-lactic acid);C60;Electrospinning;Electrical stimulation;Cell proliferation
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发布时间：2021-03-19 - 摘要：Heptaisobutyl polyhedral oligomeric silsesquioxane functionalized polystyrene (PS-POSS) was prepared by using styrene (PS) as monomers, POSS as terminator, n-BuLi as initiator, cyclohexane as solvent and tetrahydrofuran (THF) as structure modifier via anionic living polymerization. The PS-POSS was characterized by 1H-NMR,13C-NMR and GPC. The results of 1H-NMR and 13C-NMR clearly prove that the reaction of poly(styryl)lithium with Cl-POSS has been carried out and GPC chromatograms show that POSS incorporation into end of PS increased the molecular weight distribution of the PS-POSS. It is noteworthy that no obvious dimeric side-products are observed compared to conventional organic terminator. Then the effects of the species of initiator, the content of structure modifier, the molar ratio of POSS and Li, PS molecular weight, terminating reactive temperature and terminating reactive time on the functionalization efficiency were investigated. The results show that the functionalization efficiency reached the highest point when the molar ratio of THF and n-BuLi was more than 5, the molar ratio of terminator POSS and n-BuLi reached 1.1, the terminating temperature reached 60℃ and the terminating time reached 30 min. It is indicated that the reaction of poly(styryl)lithium with Cl-POSS was over when the terminating time reached 30 min. The highest functionalization efficiency is more than 80 percent. Finally, the functionalization efficiency decreased with DS molecular weight increasing as the other conditions kept unchanged.关键词：POSS;PS;Anion polymerization;End-functionalization;Functionalization efficiency
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发布时间：2021-03-19 - 摘要：A series of poly(amic acid)/polyacrylonitrile (PAA/PAN) blend fibers were prepared,and then stabilized in air in a temperature range of 200-280℃.After stabilization,the fibers were carbonized in nitrogen up to 1200℃ at different heating rates.The effects of heating rate on the chemical composition and structure of the resultant carbon fibers were investigated.Carbon fibers were characterized by scanning electron microscopy (SEM),laser Raman spectroscopy,X-ray diffraction (XRD),carbonization yield and elemental analysis (EA).The results showed that the heat treatment expelled impurites as volatile by-products leading to an increase of carbon content,which was more than 92% when the carbonization temperature was 1200℃.Longitudinal striations along the fiber axis were revealed for all the carbon fibers which were attributed to the wet spinning process.The carbonization yield increased with the increasing heating rate and the hightest yield was 52.36%.As the heating rate increased,the degree of graphitization and crystallite size increased first and then decreased.The carbon fiber prepared at a heating rate of 8 K/min was found to be optimal in terms of the low electrical resistivity and high graphitization parameters with Lc value of 1.445 nm as well as g value of 0.52.关键词：PAA/PAN blend fiber;PAA/PAN-based carbon fiber;Heating rate;Structure
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发布时间：2021-03-19 - 摘要：The differential scanning calorimetry (DSC),thermogravimetric analysis(TGA),polarizing optical microscopy (POM),X-ray diffraction (XRD),Fourier transform infrared spectroscopy (FTIR) were used to study the morphology evolution of an arylamide derivative TMB5 in different processing conditions and its effects on the β-crystal formation of iPP.The results show that TMB5 doesn't have a defined melting point but can melt gradually when heating to 200℃ or over.On cooling,the TMB5 dissolved in iPP recrystallizes in the form of thinner needles which is different from its original shape and affects significantly the subsequent morphology development of iPP and finally affects the content of β-form crystals in iPP.The compounding temperature is an important factor affecting the content of β-form crystals.When the compounding temperature is lower than the decomposition temperature of TMB5,the content of β-form crystals in iPP samples increases with increasing the compounding temperature.This can be explained by the formation of thinner needles and better dispersion of recrystallized TMB5.During the secondary processing procedure after compounding at a certain temperature,the lower melting temperature and cooling rate increase the content of β-form crystals in PP.关键词：β Nucleating agent;TMB5;Morphology evolution;β-Form crystals
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发布时间：2021-03-19 - 摘要：Lignin-based macroinitiator was synthesized by nucleophilic substitution reaction of lignin and 2-bromoisobutyryl bromide, which was used to initiate atom transfer radical polymerization of an azobenzene-containing monomer to obtain a series of lignin-graft photoresponsive liquid crystalline copolymers. The molecular structures and molecular weights of the graft copolymers were confirmed by 1H-NMR, FTIR and GPC. The thermal properties of lignin-graft azobenzene-containing copolymers showed improved behaviors superior to that of unmodified lignin by measurements of thermal gravimetric analyzer (TGA) and differential scanning calorimeter (DSC). Furthermore, the modified lignin-graft azo copolymers exhibited liquid crystalline behaviors once their average grafting ratio were higher than 72.8% and the molecular weights of lignin-graft azo copolymer were higher than 19500 correspondingly. The liquid crystalline phases of lignin-graft azobenzene copolymers were shown to be the smetic C phase and the layer spacing was 3.21 nm evaluated by small-angel X-ray scattering (SAXS) and polarizing optical micrograph (POM). Moreover, the photoresponsive properties of lignin-based liquid crystalline copolymers were investigated using UV-Vis absorption spectroscopy, and the lignin-graft liquid crystalline copolymers in solution were more sensitive than that of the as-cast films. Photochemical liquid crystal to isotropic phase transition of the copolymer was successfully obtained upon UV irradiation, and the reversible isotropic to liquid crystal phase transition was exhibited rapidly when it was exposed to visible light.关键词：Lignin;Liquid crystalline copolymer;Azobenzene;Photoresponse
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发布时间：2021-03-19 - 摘要：A series of fluorescent polymers composed of polydimethylsiloxane (PDMS) with a pyrene-terminated side chain were synthesized and characterized.The oxygen quenching of the fluorescence emission and the photophysics behaviors of the pressure sensitive paints (PSP) based on these polymers were investigated.The results showed that the side chain structure of the polymer not only affected significantly the emission intensity,oxygen quenching sensitivity and Stern-Volmer linearity,but also the storage stability of the PSP.The polymers with a longer alkylpyrene side chain terminated by pyrene chromosphere showed higher excimer emission intensity and oxygen quenching sensitivity.Otherwise,the crosslinker for the polymer filming also has some influence on the PSP properties.When tetraethyl orthosilicate (TEOS) was added for the polymer crosslinking,the storage stability of the PSP decreased obviously.But,when polyhydromethylsiloxane (PHMS A) was used,the PSP showed higher oxygen quenching sensitivity and storage stability.All of the data indicated that the pyrene-terminated alkyl side chain structure of the polymers is favorable to the stable aggregation in the condensed state,at the same time,inhibits the aggregation of the pyrene chromospheres,the PSP should have high emission intensity,oxygen quenching sensitivity,Stern-Volmer linearity and storage stability.关键词：Pressure sensitive paint;Polydimethylsiloxane;Pyrene-terminated side chain;Oxygen quenching of luminescence
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发布时间：2021-03-19 - 摘要：The silane coupling agent (KH550) was applied to modify the surface of MCM-41 and then the nitrogen absorption-desorption,Fourier transform infrared spectroscopy (FTIR) and small angel X-ray diffraction (XRD) were used to investigate the MCM-41 before and after modification.The results show that the KH550 molecules were introduced into the nanopores of MCM-41,and the -NH2 group was grafted on the nanopore surface of MCM-41 particles.Besides,the gel permeation chromatography (GPC) was used to measure the epoxy relative molecular mass.The in situ method was used to cure epoxy composite with different KH550 modified MCM-41 contents.After that,the MCM-41/EP composite was measured by different tests,including positron annihilation lifetime spectroscopy (PALS) which was applied to measure the composite free volume,and the TEM,dynamic mechanical analysis (DMA) and alternate current (AC) breakdown test were used to indicate the composite macroscopic propertes.The TEM result shows that MCM-41 could be dispersed well in epoxy at contents lower than 1.5% while agglomerate at 2.5% content.The PALS results show that the epoxy molecules were introduced into and partly occupied the mesoporous channels by the applied force and functional effect of KH550.Then,an organic-inorganic interpenetrating network nanocomposite system could be formed.Therefore the glass transition temperature (15.1%↑) and breakdown strength (22.6%↑) of the composites were improved at low MCM-41 contents.关键词：MCM-41;Epoxy;Organic-inorganic interpenetrating network;Free volume
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发布时间：2021-03-19 - 摘要：The main chain ester-containing poly(dimethylaminoethyl methacrylate)-based copolymers were successfully synthesized by the hybrid copolymerization of caprolactone (CL) and dimethylaminoethyl methacrylate (DMAEMA).The structure and properties of the resulting copolymers have been characterized by nuclear magnetic resonance spectroscopy (NMR),gel permeation chromatography (GPC),differential scanning calorimetry (DSC) and so on.The results showed that the phosphazene base 1-tert-butyl-4,4,4-tris-(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylidenamino]-2 Λ5,Λ5-catenadi-(phosphazene) (t-BuP4) displayed high activity for the copolymerization of CL and DMAEMA.The resulted copolymers consisting of CL and DMAEMA segments were random copolymers with only one glass transition temperature.The proportions of CL to DMAEMA in the copolymers were consistent with the feed ratios.The number average molecular weights of the resulted copolymers detected by GPC were in the range from 1.63×104 to 2.47×104,and the polydispersity (PDI) changed from 2.11 to 2.54.The introducing of hydrolytically cleavable ester endows the copolymer good degradability,but decreases the lower critical solution temperature (LCST) from 52.6℃ to 44.5℃.The TEM result showed that the amphiphilic polymers could form micelles around 60 nm in water.This reported method provides a facile approach for preparing stimuli-responsive degradable polymers under mild conditions,and will be useful in bio-related applications.关键词：Dimethylaminoethyl methacrylate;Caprolactone;Stimuli responsibility;Degradability.
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发布时间：2021-03-19 - 摘要：The cloudy points of acrylonitrile (AN) copolymerization with itaconic acid (IA), acrylamide (AM), methyl acrylate (MA) based on a series of different monomer composition ratios were determined by titration experiments. The various comonomers'influence on the stabilization of reactions and the relevance to the reactivity of PAN copolymerization systems were characterized by combining the methods of FTIR, DSC and TGA. The results showed that the introduction of comonomer helped to improve the cloudy point of polymerization system and the slope of cloudy point versus comonomer content lines was suggested for comparing the reactivity of copolymerization systems and the suitability of various copolymerization systems for carbon fiber precursor. The higher reactivity of AN and IA copolymerization system resulted in a preferably thermal stability performance of P(AN/IA) polymer with a lower CN fraction unreacted, the onset temperature, apparent activation energy and faster rate constant value of cyclization reaction, which was probably because the two carboxylic acid groups in the molecular structure and more priming activity points can initiate the ionic cyclization reaction, making PAN convert into more ladder structures at low temperatures.关键词：Acrylonitrile;Cloudy point;Itaconic acid;Thermal stability
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发布时间：2021-03-19 - 摘要：Polyethylene hollow spheres with diameters of 0.4-3 mm were synthesized by a two-step slurry polymerization in a single reactor with a spherical MgCl2-supported Ziegler-Natta catalyst activated by triisobutylaluminum (TIBA),in which the first step was prepolymerization with propylene under 0.1 MPa and the second step was ethylene copolymerization with small amount of propylene under 0.6 MPa at 65℃.The hollow spheres have rather smooth outer and inner surfaces and relatively uniform thickness of the shell layer.Under optimized conditions,the catalyst efficiency of the polymerization reached about 7.49 kg/g Ti·h·MPa(or 6.5 kg PE/g Cat.).The effects of amount of propylene comonomer,cocatalyst concentration (Al/Ti molar ratio) and type of cocatalyst on the particle morphology and polymerization kinetics were investigated.With increasing the Al/Ti molar ratio and the amount of added propylene,the catalytic activity was sharply increased and the particle morphology was further improved,meanwhile the kinetic curve changed from decay type to build-up type.When TEA or TEA/TIBA mixtures were used as the cocatalyst,the inner surface of the central void became rather irregular,though the whole particle was still spherical.The effects of cocatalyst on particle morphology were explained according to a diffusion controlled morphogenesis model based on the morphology of prepolymer particles.关键词：Ziegler-Natta catalyst;Polyethylene;Hollow sphere;Preparation
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发布时间：2021-03-19 - 摘要：The present work proposes a flexible replication method for bio-inspired polypropylene (PP) surfaces with microtopographies using microinjection compression molding (μ-ICM).A dual-level microstructure appears on the PP surfaces prepared via replicating the dual-level microstructure within a template.The microstructure on the PP surfaces exhibits micro ridges and high-aspect-ratio micropillars with conical top.When water is dropped onto the micropillars,the droplet penetrates into the upper part of the gap between the micropillars due to the relatively large gap,resulting in a mid-adhesive superhydrophobicity for the PP surfaces.The silica nanoparticles (SNPs) coated on the template are transferred to the viscous state-dominated melt during its filling in μ-ICM,and firmly adhered to the skin of the dual-level microstructure,endowing the surface with submicron-scale or micron-scale roughness and so forming hierarchical microstructures.On the microstructures coated with hydrophilic SNPs,the droplet wets the intermicropillar areas on the surface completely due to high surface free energy,and the prepared surface has a water contact angle (CA) of 161.9° and a roll-off angle of above 90°,exhibiting extremely high adhesion with superhydrophobicity (i.e.,petal effect); on the microstructures coated with hydrophobic SNPs,the water is repelled by the hydrophobic SNPs and so the adhesion to the surface is weak,and the prepared surface has a CA of 163.5° and a RA of 3.5°,exhibiting extremely low adhesion with superhydrophobicity (i.e.,lotus effect).关键词：Hierarchical microstructure;Wetting characteristics;Polypropylene;Silica nanoparticles;Microinjection compression molding
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发布时间：2021-03-19 - 摘要：This paper studied the influences of pH, salinity and additive agent (sodium dodecyl sulfonate (SLS)) on the properties of partially hydrolyzed hydrophobically modified polyacrylamide (HMHPAM) by dissipative particle dynamics (DPD) simulation combined with viscometry and AFM observations (atomic force microscopy). The effects of electrical shielding effect and water absorbing ability of salts and pH on the behavior of HMHPAM molecules were investigated through changing the interaction parameter between different beads. The conformation of polymer chains described by the root-mean-square (RMS) end-to-end distance and simulation snapshot was compared with the viscosity. It was found that, for the HMHPAM, the water absorbing effect of salts seriously reduced the viscosity of polymer solutions, but the influence of electrical shielding of salts was not obvious. The hydrolyzed groups of HMHPAM existed in the form of acrylic acid in acidic solutions and acrylic acid anion in alkaline solutions. The electrostatic repulsion between different acrylic acid anion groups can stretch the polymer chains and increase the solution viscosity, which results in the higher viscosity of HMHPAM solutions in alkaline environment than in alkaline environment. The environmental responsive behaviors of HMHPAM were studied to optimize the applied condition of flooding process. The added SLS can influence the interfacial phase properties and bulk phase properties of HMHPAM. It increased the viscosity of polymer solutions and reduced the oil/water interfacial tension of polymer systems. In the HMHPAM solution, the SLS can enter the hydrophobic domains of polymer chains through hydrophobic interaction, which can enlarge the polymer chains and increase the system viscosity. HMHPAM can be adsorbed onto the oil/water interface and reduce the oil/water interfacial tension of the system. The addition of SLS may reduce the interfacial tension obviously, which helps to broaden the potential application of HMHPAM.关键词：Partially hydrolyzed hydrophobically modified polyacrylamide;pH;Salinity;Sodium dodecyl sulfonate;DPD simulation
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发布时间：2021-03-19 - 摘要：The fly ash floating beads were covered by polyaniline (FAFB/PAn) by using in situ polymerization method.Sol gel-hydrothermal method was introduced to prepare FAFB/PAn/BaTiO3 composites.FAFB/PAn/BaTiO3 composites had core/shell structure with multilayer,which was composed of the core as hollow FAFB and the first shell as conductive layer PAn and the second one as insulating layer BaTiO3.The structure and performance of the composites were analyzed by FTIR,XRD,SEM,four point probe technique and LCR.The suspension and shear stress of electrorheological fluid were tested.The results of FTIR and XRD showed that PAn and BaTiO3 could successfully be coated on the surface of FAFB by this method.The results of conductivity showed that the value of FAFB/PAn/BaTiO3was 7.8×10-4 S·cm-1,and rose almost by two orders of magnitude in comparison with BaTiO3.It had better dielectric properties in the 1-2000 kHz frequency range.The max value of εr reached 598 if f = 1 kHz was provided and with the increase of frequency,the dielectric constant decreased correspondingly.The maximum of tanδ was 1.14 at f=1 kHz and its value decreased to 0.75 until 200 kHz.Comparison with the suspension stability of them,FAFB/PAn showed better suspension ratio as 88% than BaTiO3 and FAFB/PAn/BaTiO3 after 7 days,while the values of the latter two was similar as only 60%.FAFB/PAn/BaTiO3 based electrorheological fluid showed a significant ER effect and obvious higher capability of breakdown resistance under electric field.When the applied electric field was 4.0 kV/mm,the shear stress arrived at 631 Pa.关键词：Fly ash floating bead;BaTiO3;Polyaniline;Electrorheological property;Dielectric property
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发布时间：2021-03-19 - 摘要：The polyamide 6(PA6)/KCl composites were prepared by the melt blending method.The effect of KCl content on the crystallization behavior,as well as the rheological and mechanical properties of the composities was studied by differential scanning calorimeter (DSC),advanced rheometer (ARES-G2),Fourier fransform infrared spectrometer (IR) and universal testing machine.The mechanism of confined crystallization was also systematically investigated.The mechanical property results show that the tensile strength and notch impact strength increased first and decreased finally with the increase of KCl content.When the amount of KCl was 3 phr,the tensile strength and notch impact strength of the PA6/KCl composities reached the maximum values of 82.67 MPa and 7.34 kJ/m2,respectively,which presented 10.8% and 34.68% improvement compared to those of the pure PA6.The dynamic mechanical property measurement results demonstrated that the storage modulus of the composite materials was higher than that of pure PA6 in the measuring temperature range,and the storage modulus of the composites increased with the increase of KCl content.The crystallization behavior results reveal that with the addition of KCl content,the temperature of nucleation,the growth temperature of crystal,the melt temperature of crystal and the glass transition temperature of spherulites dramatically decreased.The density and the rate of nucleation also decreased gradually,the crystallization ability of PA6/KCl composites decreased and the crystallinity decreased from 20.30% to 19.34%,the crystallization induction time gradually increased.The rheological property results showed that with the increase of KCl content,the composites exhibited zero shear viscosity and pseudo plastic fluid behavior,and the phenomenon of shear thinning became more and more obvious,the changes in relaxation mechanism led to the gradually increase in the characteristic relaxation time τ1,τ2 and τ3.关键词：PA6;Blend;Crystallization;Rheology;Mechanical properties
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发布时间：2021-03-19 - 摘要：A carboxyl-terminated polyether polysiloxane (CPSA) was synthesized by the ring-opening reaction between polyether amino terminated polydimethylsiloxane (BPEAS) and maleic anhydride (MAn). In the isopropanol media, the novel supramolecular CPSA/QPEPS was prepared by electrostatic interactions of supramolecular self-assembly, which were formed between CPSA with negative charges and long carbon chain quaternary ammonium modified polyether polysiloxane QPEPS with positive charges. The chemical structures of the carboxyl-terminated polyether polysiloxane (CPSA) were characterized by FTIR,1H-NMR. Then, the application performances of CPSA/QPEPS were investigated by HY-BDY, contact angle, softness tester, microplate reader, X-ray photoelectron spectroscopy (XPS). Finally, the morphology of CPSA/QPEPS was observed by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM), respectively. The results indicated that, when the mass ratio of QPEPS to CPSA was 1:1, the bending rigidity (BR) and the softness of fabric treated by CPSA/QPEPS were decreased and increased, respectively. The wetting time of the treated fabric was only 4.39 s, moreover, the inhibition rate against bothE. coli and S. Aureus of the treated fabric reached 71%. Also, the CPSA/QPEPS exhibited a favorable film-forming properties. The surface of CPSA/QPEPS films shows a continuous mountain-like morphology and the root mean square roughness (Rq) of the CPSA/QPEPS film achieved 2.57 nm via 5 μm × 5 μm scanning field.关键词：Polyether-modified polysiloxane;Supermolecule;Film morphology;Textile;Antibacterial activity
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发布时间：2021-03-19
Research Article
- 摘要：3,3-Bis[4-(4-aminophenoxy)phenyl]phthalide (Ⅰ) and 3,3-bis[4-(4-amino-2-trifluoro-methylphenoxy)phenyl]phthalide (Ⅱ) were prepared through the nucleophilic substitution reaction of 4-nitrochlorobenzene and 2-chloro-5-nitrobenzotrifluoride with phenolphthalein in the presence of potassium carbonate to yield the intermediate dinitro compounds 3,3-bis[4-(4-nitrophenoxy) phenyl]phthalide and 3,3-bis[4-(4-nitro-2-trifluoromethylphenoxy) phenyl]phthalide, followed by catalytic reduction with hydrazine and Pd/C. Eight kinds of phthalide-containing polyimide (PI) films were prepared from diamines Ⅰ and Ⅱ and four kinds of dianhydrides 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-hexafluoroisopropylidinedi(phtalic anhydride) (6FDA)via thermal imidization of poly(amic acid)s separately. The chemical structure and properties of these PIs were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), ultraviolet-visible spectrophotometry (UV-Vis), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and solubility testing. These obtained experimental results showed that these PIs containing phthalide groups showed excellent thermal properties, optical properties and solubility. These PIs exhibited amorphous structure and showed good solubility in some aprotic polar organic solvents such as NMP, DMF, even soluble in weak polar solvent such as THF. They also exhibited excellent thermal properties, 10% thermal decomposition temperature above 498.9℃ and the glass transition temperature (Tg) above 258℃. The UV-Vis transmittance spectra showed that the PIs derived from CBDA, ODPA, 6FDA possessed optically colorless and transparent properties in the visible region.These obtained PIs containing phthalide groups could be expected to be used in the microelectronic and opto-electronic applications.关键词：Polyimides;Phthalide group;Solubility;Thermal property;Optical property
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发布时间：2021-03-19
Research Bulletin
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