最新刊期
卷 ， 期 10 ， 2013
- 摘要：Cellulose naphthoate (CNp) and its synthesis were first reported in this work.Using ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as the reaction medium,homogeneous acelytion of cellulose with naphthoyl chloride was carried out under the mild reaction conditions,and a series of CNps with the degree of substitution (DS) in a range of 0.85~2.61 were synthesized.The DS values of CNps could be controlled by adjusting the reaction temperature,the reaction time and the molar ratio of naphthoyl chloride/anhydroglucose unit (AGU) in cellulose.The chemical structure and thermal properties of CNps were characterized by means of FTIR,NMR,DSC and TGA.With the increase of the DS,the glass transition temperature of CNp decreased.The synthesized CNps exhibited improved solubility in some organic solvents,and CNp films could be easily prepared by solution casting.The CNp exhibited strong ultraviolet absorption peaks at 323.2 nm,300.4 nm and 243.8 nm,which was similar to naphthalene.Meanwhile,the CNp also showed good fluorescence property in the range of 320~600 nm.Therefore,the synthesized CNp may have some potential applications in packing,gas separation membrane,coating,as well as some functional materials.关键词：Cellulose;Cellulose naphthoate;Ionic liquid;Synthesis
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发布时间：2021-03-19 - 摘要：A methyl acrylate monomer MAMIS with ureidopyrimidinone (UPy) unit was synthesized.The molecular structure of MAMIS was confirmed by 1H nuclear magnetic resonance (1H-NMR) spectrum,Fourier-transform infrared (FTIR) spectrum,electrospray ionization-mass (ESI-MS) spectrum and elemental analysis.A kind of organogel with UPy units (defined as UPy-gel) was prepared through traditional radical copolymerization of MAMIS and other acrylate monomers in DMSO.The chemical composition and morphology of the UPy-gel were characterized by elemental analysis,FT-IR,and scanning electron microscopy (SEM).The glass transition temperature (Tg) of the gels was measured by using a differential scanning calorimeter (DSC).Compared with the oganogels without UPy units,the UPy-gel displays similar microscopic morphology and an increased Tg.The macroscopic assembly of the gels under the driving of UPy quadruple hydrogen bonding was further investigated.The results indicated that the UPy-gel pieces aggregated together in toluene,and the aggregated UPy-gels gradually separated in DMSO.This process could be repeated for many times.As increasing the content of UPy units in the gels or by using a solvent with lower polarity,the aggregation strength of the gels became higher,demonstrating the solvent-sensitivity of the gels.Driven by quadruple hydrogen bonding,the macroscopic assembly of the gels enabled the transmission of dye molecules from dyed gels to undyed ones.关键词：Macroscopic self-assembly;UPy unit;Quadruple hydrogen bond;Organogel
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发布时间：2021-03-19
Rapid Communications
- 摘要：The poly(vinyl alcohol)/nano-hydroxyapatite (mPVA/n-HA) composites were prepared by thermal processing of PVA,and the solid state shear milling technology(S3M) developed in SKLPME was adopted to improve the dispersion of n-HA in PVA matrix.The structure and properties of the composites were also studied.The results showed that the hydrogen bonds or [HO]Ca2+[OH] between n-HA and PVA were enhanced under the strong effects of mixture,dispersion and activation of pan-milling equipment,which could effectively improve the interfacial strength between n-HA and PVA,and increased the dispersion of n-HA particles in PVA matrix.The strong interactions between n-HA and PVA largely increased the initial thermal decomposition temperature of PVA,and endowed the composites with large thermal processing windows.These interactions could also act as the physical crosslinking points in system,thus inhibited the penetration of water into the composites,and shortened the time to the equilibrium swelling,i.e.the water resistance of the composites was improved.The well dispersion of n-HA particles in matrix could efficiently exert their reinforcement effect on PVA,thus improved the tensile strength and elongation of the composites at break,e.g.,the tensile strength and elongation of the composite with 20 wt% n-HA were 27.7 MPa and 569.7%,respectively increased by 110% and 76% compared with mPVA.关键词：Poly(vinyl alcohol);Nano-hydroxyapatite;Thermal processing;Structure and properties
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发布时间：2021-03-19 - 摘要：The poly(butylene succinate) (PBS) and aminopropylisobutyl polyhedral oligomeric silsesquioxanes (POSS) nanocomposites were prepared by solution-casting method.The effects of POSS on the microstructure,crystal structure,crystallization behavior,spherulitic morphology and spherulite grow rate,mechanical properties and thermal stability of PBS/POSS nanocomposites were investigated with various techniques.Scanning electron microscope measurements revealed that POSS particles were well-dispersed uniformly on the nanoscale in the PBS matrix and had a good interfacial interaction with PBS chains.Wide-angle X-ray diffraction patterns showed that the POSS molecules are able to crystallize in PBS matrix,but do not affect the crystalline structure of PBS matrix.Differential scanning calorimetry results indicated that the incorporation of POSS particles into PBS matrix,unexpectedly,decreased the crystallization temperature during nonisothermal melt crystallization and prolonged the crystallization time during isothermal crystallization.The nucleation effect of such POSS on the crystallization of PBS is extraordinary limited; furthermore,it hindered the motion of PBS chains and decelerated the spherulite growth rate,as confirmed by polarized optical microscopy.Mechanical properties were evaluated by Instron and dynamic mechanical analysis.The Young's modules and storage modules of the nanocomposites were enhanced relative to PBS by the addition of POSS,however,the tensile strength was not much improved and the elongation at break was reduced for the nanocomposites.Glass transition temperature (Tg) of the PBS/POSS nanocomposites increased slightly with increasing POSS content,which indicated that the molecular mobility of amorphous PBS chains was constrained in the nanocomposites.The above results indicated that the retarded crystallization of PBS and the variation of mechanical properties of the nanocomposites in the presence of POSS were ascribed the stronger hydrogen-bonding interactions between the POSS molecules and the PBS matrix as well as the network formation based on the POSS physical crosslinking points in the PBS/POSS nanocomposites.关键词：Poly(butylene succinate);Polyhedral oligomeric silsesquioxanes;Nanocomposites;Retarded crystallization
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发布时间：2021-03-19 - 摘要：The surfaces of glass fiber were coated with ethylene-maleic anhydride copolymer or/and multiwalled carbon nanotube through electrostatic absorption method,thus GF-EMA,GF-MWCNT and GF-EMA-MWCNT hybrid reinforcements were prepared.Nylon 6 and nylon 6/carbon nanotube based composites reinforced with as-prepared hybrid reinforcements were fabricated by melt mixing.The results have shown that the acid anhydride groups of the EMA copolymer can react with the amino groups of the PA6 resin to form cross-linked structures.Meanwhile,the EMA on the glass fiber surfaces can significantly improve the interfacial adhesion between GF and PA6 matrix,thus enhance the mechanical properties of the GF-EMA reinforced composites.Compared to PA/GF composites,the measured tensile strength,flexural strength and modulus of PA/GF-EMA composites increased by 11.4%,21.5% and 28.9%,respectively.The incorporation of GF-MWCNT reinforcements effectively enhanced the electrical properties of PA6/CNT composites due to the compact and well-dispersed MWCNT conductive network formed on the fiber surfaces.The surface electrical resistivity of GF-MWCNT reinforced PA6/CNT composites was reduced by about 2 orders of magnitude compared to that of the PA6/GF/CNT composites.The GF-EMA-MWCNT hybrid structures can combine the modification effect of GF-EMA and GF-MWCNT structures,thus the GF-EMA-MWCNT reinforced composites exhibited improvements of mechanical and electrical properties at the same time.关键词：Electrostatic absorption;Hybrid reinforcement;Nylon 6;Ethylene-maleic anhydride copolymer;Carbon nanotube
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发布时间：2021-03-19 - 摘要：Surface modification of commercial ZnO nanoparticles (ZnO NPs,300 nm in diameter) was carried out by using polymethylacrylic acid (PMAA) chains.And by using the modifed-ZnO NPs (mZnO NPs) and N,N'-methylene-bis-propanamide (BIS) as physical and chemical cross-linkers,respectively,novel antibacterial mZnO/PAAm nanocomposite hydrogels with physical/chemical double cross-linked structure were prepared via redox initiated polymerization.FTIR,TGA and SEM were used to study the surface modification of ZnO NPs and the prepared mZnO/PAAm nanocomposite hydrogels.Mechanical properties,swelling behavior and antibacterial test of these hydrogels were also investigated.Results show that mZnO NPs dispersed uniformly in both aqueous solution and hydrogels' network through hydrogen bond interactions between OH groups on the surface of mZnO NPs and COOH groups on covered PMAA chains (the cover ratio was 3.64 wt%) and served as a physical cross-linker.It was also revealed that in correspondence with the content of physical and/or chemical cross-linkers,the mechanical properties and swelling behavior (swelling ratio) of these hydrogels could be controlled within 140~800 kPa and 55%~170%,respectively.Further the antibacterial test illustrated such ZnO NPs implanted hydrogels inhibit the growth of several kinds of oral anaerobes.These hydrogels may provided a simple approach to achieve the integration of structure and function.关键词：ZnO nanoparticles;Surface modification;mZnO/PAAm nanocoposite hydrogel;Physical/chemical double crosslinking structure;Antibacterial hydrogels
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发布时间：2021-03-19 - 摘要：Self-assembly of linear,asymmetric ABA triblock copolymers is investigated using a simulated annealing method,in which the copolymers are anchored regularly onto a planar surface through one end of the A-blocks with an equal space and immersed in a selective solvent that is good for the middle B-blocks but poor for the tethered and outer A-blocks.For systems with different lengths of the middle B-blocks,the influence of the asymmetry of the copolymer chains on the morphologies of the end-anchored triblock copolymers is studied,and phase diagrams for different systems are constructed.Snapshots,polymer density profiles,fraction of the folded chains and typical chain conformations are used to provide detailed information about the system.The simulation results show that the copolymers can self-assemble to form a variety of morphologies,such as structures with one A-rich layer including semispherical pinned micelles,wormlike micelles,stripe structures,connected stripe structures and perforated layered structures,and structures with two A-rich layers including semispheres-spheres,wormlike micelles-spheres and stripes-spheres.It is found that morphological transitions from structures with one A-rich layer to structures with two A-rich layers can be induced by increasing the length of the outer A-blocks or/and the length of the B-blocks as well as by decreasing the length of the anchored A-blocks.These morphological transitions are illustrated based on an analysis of the average contact number between different species in the system.Our simulation results were compared with the available experimental studies.关键词：Asymmetric triblock copolymers;Simulated annealing;Anchored triblock copolymers;Self-assembly
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发布时间：2021-03-19 - 摘要：Microstructures in the dual- and three-level hierarchical templates are replicated on the surfaces of large-sized polypropylene (PP) samples using microinjection-compression molding (-ICM) in a single step.Results indicate that the single- and dual-level structured surfaces can be molded via the former template under lower and higher compression forces,respectively.The single-level micro blade structure yields an increase in static contact angle (CA) from the intrinsic value of the PP (85.0) to 134.2 on the molded surface.The dual-level structure involving micro blades and micro pyramids results in the lotus-leaf effect (CA150,rolling angle RA5) on the surface.The 250 m diameter micro columns,the top surfaces of which show the aforementioned dual-level microstructure,are uniformly distributed on the three-level hierarchical surface molded via the later template.The CA and RA values on this surface are 164.5 and above 90,respectively.Thus a functional surface displaying the petal effect is obtained.The high level of RA is resulted from the localized noncomposite wetting state near the upper edge of micro columns.This work gives an insight into the design,manipulation and mass production of superhydrophobic surface.关键词：Microinjection-compression molding;Superhydrophobic;Lotus-leaf effect;Petal effect;Hierarchical structure
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发布时间：2021-03-19 - 摘要：Azobenzene-terminated PNIPAM (PNIPAM-AZO) with temperature and light dual-sensitive properties was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) with azobenzene-containing trithiocarbonate (TTC-AZO) RAFT reagent,and the structure was confirmed by UV-Vis,FTIR and 1H-NMR spectroscopy.The thermosensitivity and photosensitivity of PNIPAM-AZO aqueous solutions were investigated.The results show that PNIPAM-AZO aqueous solutions have rapid and reversible trans-cis photoisomerization properties.The lower critical solution temperature (LCST) of PNIPAM-AZO is lower than that of poly(N-isopropylacrylamide) (PNIPAM),and the LCST of PNIPAM-AZO decreases with the increase of both polymer number molecular weight and aqueous solution concentration,and increases as the molecular weight distribution broadens.The LCST of PNIPAM-AZO aqueous solutions of higher concentrations first decreases and then increases when the addition amount of -cyclodextrin (-CD) increases.However,for lower concentrations of PNIPAM-AZO aqueous solutions,the LCST first increases and then remains fairly constant.When subjected to ultraviolet (UV) and visible light irradiation alternately,the LCST of PNIPAM-AZO aqueous solution increases and decreases reversibly with a temperature amplitude of 0.7 K,which shows light-tunable thermosensitivity.关键词：Poly(N-isopropylacrylamide);Thermosensitivity;Photosensitivity;Azobenzene;Molecular recognition
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发布时间：2021-03-19 - 摘要：Blending type ABS resin with different polybutadiene rubber (PB) and polyacrylonitrile (AN) contents is prepared by melt blending,and used in preparing PC/ABS (70/30) blends.The effects of the PB and AN contents in SAN phase and the PC molecular weight on the structure and properties of blending PC/ABS systems are investigated.The results show that:when the AN contents were fixed,samples with 6.3 wt% of PB content exhibited the best tensile properties; while the PB contents were fixed,increasing AN contents led to the better tensile properties of PC/ABS (70/30) blends,although its effect on the structure and properties of PC/ABS blends was not as significant as that of PB contents.And basic law in the tensile properties of PC/ABS blends with the PB content changes does not change fundamentally with the AN contents change.Dynamic mechanical analysis and scanning electron microscopy give exactly the same trends of thermodynamic compatibility (PC-ABS) and phase morphology with PB and AN contents.Therefore,the influences of PB and AN contents on the tensile properties of PC/ABS blends can be well understood.The changes on thermal stability of PC/ABS blends with the PB contents and AN contents change are not obvious.The tensile properties of PC/ABS blends have a significant dependence on the PC molecular weight,and when the PC molecular weight increased from 1.5104 to 2.5104 its tensile strength and elongation at break were increased by 35% and 98%,respectively.关键词：Polycarbonate;Blending ABS resin;PB content;AN content
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发布时间：2021-03-19 - 摘要：Samples were taken every half an hour during reaction of the resole phenolic-paraformaldehyde resin reaction process,strongly cooled to block any further reaction.The relative molecular mass and distribution of the synthetic reaction process of the phenolic-paraformaldehyde resin were determined both by gel-permeation chromatography (GPC) and field desorption mass spectrometry (FD-MS).The GPC was used to analyze quantitatively the composition contents with the synthetic reaction process.The FD-MS was used to give the molecular ion peak of the every phenol unit without fragment ion peaks.The real molecular mass and the structures of every composition can be determined by FD-MS.The structural transformation during the synthetic reaction process of the phenolic-paraformaldehyde resin can be spread out clearly by combining GPC method with FD-MS method.The results show,the free phenol decreased from 70% to 7% with time.The free phenol decreased fast at the beginning with the rapid addition reaction and slowly near the end.For the two monohydroxymethylphenols (2-HMP and 4-HMP),2-HMP had the maximum value at the beginning and then decreased with time,4-HMP increased first,had the maximum value after 120 min and then decreased quickly.The two dialcohols (2,4-DHMP and 2,6-DHMP) increased first,had the maximum value at about 210~240 min and then decreased quickly.The trialcohol (2,4,6-THMP) also increased first and then decreased,it had the maximum value after 180 min.The two-ring and the three-ring compounds increased with time.They increased slowly at the beginning and fast with the rapid condensation reaction near the end.关键词：Phenolic resin;Paraformaldehyde;Field desorption mass spectrometry (FD-MS);Gel-permeation chromatography (GPC);Synthetic reaction process
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发布时间：2021-03-19 - 摘要：PLLA/CA composites porous ultrafine fibers with diameters of 0.89~1.21 m and mesopores of 61~123 nm were prepared by electrospinning using DMF/DCM or acetone/DCM as solvent.The effects of composition of solvent,ratio of solvent,concentration and environment humidity on the diameter and porosity of PLLA/CA composites porous ultrafine fibers were investigated.The fiber diameter and surface morphology were studied using scanning electron microscopy (SEM),and specific surface area was calculated by N2 adsorption/desorption isotherms.The PLLA/CA composites porous ultrafine fibers electrospun from acetone/DCM showed smaller pore diameter and larger specific surface area compared with those from DMF/DCM solvent.This was attributed to the boiling point of acetone/DCM was lower than that of DMF/DCM,the more decrease of polymer temperature when solvent was volatized,the sharper thermal induced phase separation,so the density of pore was increased.Moreover,with increasing of DCM content,the density of pore and specific surface area of PLLA/CA composites porous ultrafine fibers were increased.With increasing of polymer concentration from 3% to 15%,the morphology was transformed from porous particle to bead on the string,and finally forming uniform porous fibers.The characteristic PLLA/CA porous fibers was formed by thermal induced phase separation (TIPS) mechanisms,because of the sharp temperature drop caused by the quick solvent evaporation in the electrospinning process.Moreover,because the interconnected porous structure was formed,the phase separation took place in a spinodal decomposition mechanism in this system.关键词：Electrospinning;Poly(L-lactic acid);Cellulose acetate;Porous fiber
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发布时间：2021-03-19 - 摘要：Based on the strong adhesive behavior of polydopamine on solid surface,PP film were modified via dispersing in a dopamine solution at room temperature.The properties of modified films were mainly characterized by contact angle measurements (CA) and scanning electron microscopy (SEM).The peeling strength was measured using a T-peel test performed on an electronic universal testing machine.The results of CA showed that the hydrophilic properties of the film could be controlled by adjusting pH value,dopamine concentration and reaction time.The effects of polydopamine on film surface morphologies were investigated by SEM.The contact angle reduced from 105 to about 63 under the reaction conditions of pH 8.5,the concentration at 2.0 g/L for 24 h,which meant the hydrophilicity of PP films was significantly improved by the attachment of polydopamine.The durability of the modified layer was also investigated.The results indicate that the modified surface could retain its hydrophilic properties after immersing in water at 60 ℃ for 48 h or in a solutions of pH values between 1.0 and 10.0.There was no polydopamine dreg evidently split away from the PP film after durability test.Moreover,the peeling strength between polydopamine and PP film was about (25.33.0) N/m.关键词：Polydopamine;Polypropylene;Surface modification
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发布时间：2021-03-19 - 摘要：Studies on viscoelastic properties of two types of isotactic polypropylene (iPP-1 and iPP-2) and their composites filled with carbon nanotubes (CNTs) (CNTs/iPP composites) were carried out by using rheometer.The influences of viscoelastic properties on the melt extrusion behaviors of iPPs and CNTs/iPP composites were further investigated by using capillary rheometer.The rheological results demonstrate that at 200 ℃ the viscosity and storage modulus G' for iPP-1 are obviously lower than that for iPP-2.The appearance of frequency-independent plateau of G' at low frequencies and solid-like elastic behaviors for the CNTs/iPP composites containing CNT mass fraction of 5 wt% indicate the formation of entangled CNT networks in the composites.Both iPPs and CNTs/iPP composites exhibit prominent shear-thinning behaviors and the composites exhibit relatively higher viscosities and shear stresses than their iPP counterparts.The extrudate distortion and die swell for CNTs/iPP composite melts decrease compared with iPPs due to the formation of CNT networks in the composites.Although the die swell can still be observed at the high applied shear rates for the CNTs/iPP composite with the relatively high viscoelastic iPP-2 as the matrix,an appreciable phenomenon of die shrinkage rather than the common die swell at the low applied shear rates is observed for this CNTs/iPP composite.More interesting,the particular die shrinkage phenomenon is observed at all the applied shear rates for the CNTs/iPP composite with the relatively low viscoelastic iPP-1 as the matrix.The above results can be explained by that the CNT networks in the composites under shear might be able to restrict the deformation and elastic relaxation of iPP chains,which have the relatively low viscoelastic properties.关键词：Polypropylene;Carbon nanotubes;Networks;Rheology;Die shrinkage
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发布时间：2021-03-19 - 摘要：Carbon nanotube film (CNTF) interlayer toughened carbon fiber (CF) reinforced epoxy resin (EP) hybrid composites were fabricated via resin transfer molding (RTM) processing in this paper.Multi-walled carbon nanotubes were prepared by chemical vapour deposition,and carbon nanobute films were prepared through vacuum filtration.Model I interlaminar fracture toughness GIC of laminates and model II interlaminar fracture toughness GIIC of laminates are used to characterize the fracture toughness of the RTM laminates.Furthermore,the toughening mechanism is discussed through microstructure of the fracture surface combining mechanical properties.The compact degree of the carbon nanotube films was influenced by the ratio of the multi-walled carbon nanotubes,which led to different impregnation of the carbon nanobute films to the epoxy resin.Experimental results indicated that the carbon nanotube films from carbon nanotubes of large aspect ratios exhibited better impregnation effect than those films from carbon nanotubes of small aspect ratios.The carbon nanotube films intercalated in the interlayer of the composites between the carbon fiber and the matrix resin as a whole laminated structure,and they still kept a continuous grid structure in the CNTF/CF/EP hybrid composites.As to the model I interlaminar fracture toughness GIC of laminates,the carbon nanotube films have no obvious improvement on the GIC value.However,the carbon nanotube films laid between the carbon fiber layers changed the failure mode of the CF/EP composites,leading to increased initial failure load and breaking load.As to model Ⅱ interlaminar fracture toughness GIIC of laminates,experimental results exhibited that the reinforcing efficacy on the sliding mode shear failure was remarkably increased for the CNTF/CF/EP hybrid composites.Model II interlaminar fracture toughness GIIC of laminates has increased from 1292 J/m2 of the CF/EP to 2869 J/m2 of the CNTF/CF/EP hybrid composites.There is 120% amplification in GIIC testing value.Microstructures of the CF/EP composites and the CNTF/CF/EP hybrid composites were characterized through scanning electron microscope (SEM) for understanding the prominent improvement on the toughening properties.SEM pictures showed that there was strong shear history of the carbon nanotube films via the sliding mode failure.The carbon nanotubes absorbed a great deal of energy through shear sliding and hindered crack growth,leading to increase of the GIIC value outstandingly.关键词：Composites;Carbon nanotube film;Interlaminar toughening;Resin transfer molding
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发布时间：2021-03-19 - 摘要：Poly(ethylene oxide) (PEO) with different molecular weight (PEO10k,PEO4k,PEO2k) was modified by octadecyl end groups.The end group tethering density on the folding surface was tuned by changing the molecular weight of PEO.The crystallization and melting behavior of modified PEO were studied by differential scanning calorimetry (DSC),polarized optical microscopy (POM) and atomic force microscopy (AFM).DSC results show that the PEOs tend to form nonintegral-folding (NIF) crystals after end-group modification.For PEO with molecular weight of 104,octadecyl end groups significantly hinder the nucleation of PEO and cause a slight increase of free energy of folding surface.However,it has very little effect on the equilibrium melting temperature.For PEO4k and PEO2k after end-group modification,the equilibrium melting temperatures greatly depressed.The octadecyl end group hampers the transformation of PEO4k IF(1) crystal to IF(0) crystal.In situ AFM observation shows the stability of PEO2k NIF crystals increases greatly and the chain length arranged in the IF(0) crystal is also shortened after introducing the octadecyl end groups.The thickening of lamellae will increase the tethering density of octadecyl end groups on the lamella surface,while the tendency of the octadecyl chains to adopt maximum conformation entropy requests the tethering density to be decreased.The competition between these two processes leads to the above changes of crystallization and melting behaviors.关键词：Poly(ethylene oxide);End group effect;Confined crystallization;Tethering density
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发布时间：2021-03-19 - 摘要：Microstructure and rheological properties of ferrocene modied branched poly(ethylene imine)(Fc-BPEI) in aqueous solutions were investigated through dynamic light scattering,transmission electron microscopy (TEM) and rheometry.The influences of shear,concentration and temperature on microstructure and rheological behavior of Fc-BPEI aqueous solutions were also explored.Compared with pure BPEI,the molecule size of Fc-BPEI obviously increases.It is found that the dominate association in aqueous solutions transfers from intramolecular to intermolecular association with the increase of concentration and intermolecular associations are formed,inducing a considerable increase in viscosity of Fc-BPEI aqueous solutions.However,these Fc-BPEI aqueous solutions represent a typical rheological behavior of Newtonian fluid.After undergoing continuous heating-cooling treatments,the viscosities of Fc-BPEI aqueous solutions increase significantly.Furthermore,the increment of viscosity gradually decreases as the heating-cooling treatment repeats.The dynamic rheological results indicate that heating-cooling treatment could lead to the changes in macromolecular association and resulting microstructure of polymers.Some Fc-BPEI macromolecules could simultaneously participate in multiple intermolecular association structures and consequently a large structure of macroscopic network-like forms.Fc-BPEI aqueous solutions present obvious shear-thinning due to the occurrence of associative network after thermal treatments and anti-shear ability of high concentration solutions of Fc-BPEI remarkably improves.关键词：Branched poly(ethylene imine);Hydrophobic modification;Rheological behavior;Association
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发布时间：2021-03-19
Research Article
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