最新刊期
卷 ， 期 7 ， 2013
- 摘要：Regarding to the interfacial diffusion studies strongly relating to the polymer processing,this article provides a review on the basic theories of mutual diffusion at polymer interfaces from the dynamics and thermodynamics viewpoints.Various conventional methods used to study the interfacial diffusion of polymer melts are systematically introduced according to the research progresses on polymer interfacial diffusion.In particular,rheology as a newly developed method to determine effectively the dynamic interfacial diffusion process of polymer melts,is emphasized in details in the aspects of its application principle and progress,which plays important roles in developing the polymer diffusion theories from the molecular dynamics viewpoint and helps design interfacial structures of polymers and improve performances of polymers in the processing.The prospects of studying the interfacial diffusion of polymer melts are proposed.关键词：Polymer;Interface;Diffusion;Rheology
- 57
- |
- 25
- |
- 1
发布时间：2021-03-19
Reviews
- 摘要：Silver/polyaniline (Ag/PANI) nanocomposites doped with nitric acid (HNO3),p-toluenesulfonic acid (TSA) and 5-sulfosalicylic acid (SSA),respectively,were synthesized in reversed micellar solutions, and the reaction was performed via in situ reduction of silver nitrate in aniline by photolysis.Reduction of the silver nitrate in aniline leads to the formation of silver nanoparticles which in turn catalyze oxidation of aniline to polyaniline.The structure and morphology of Ag/PANI nanocomposties doped with different acids were analyzed and characterized by ultraviolet-visible spectroscopy (UV-Vis),Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD) and scanning electron microscopy (SEM),respectively.The conductivity of Ag/PANI nanocomposites was measured with the four-probe method.UV-Vis and FTIR results indicate that the conductivity and the spectra of Ag/PANI nanocomposites doped with proton acids are affected by the counter anion of the dopants.The counter anions size of TSA is bigger than that of HNO3 and SSA,and its conductivity,shifting of FTIR and UV-Vis spectra are more stronger than the two others.A slightly broadened XRD pattern, indicating nano-sized particles,is achieved with cubic silver.The crystallinity of the PANI doped with TSA is higher than that of the PANI doped with the other two acids.SEM of the Ag/PANI nanocomposites shows that the Ag/PANI nancomposites with the core-shell structure formed with a smooth PANI shell around a core of silver nanoparticles are all achieved in different acids.Compared with the Ag/PANI nanocomposites synthesized by the other two acids,Ag/PANI nanocomposites doped with TSA exhibit the more outstanding conductivity,achieving 215.14 Scm-1.关键词：Reverse micelle;Polyaniline;Silver;Nanocomposites;Doping
- 33
- |
- 13
- |
- 7
发布时间：2021-03-19 - 摘要：The thermal degradation behavior and combustion of rigid polyurethane foams (RPUF) with expandable graphite (EG) and ammonium polyphosphate (APP) were investigated by thermal gravimetric analysis (TG),X-ray photoelectron spectroscopy (XPS),limiting oxygen index (LOI) and smoke density test.On this basis,the effect of EG/APP on the combustion of RPUF/tris(-chloroisopropyl)phosphate (TCPP) composites was studied by CONE calorimeter.The results showed that the interaction between EG and APP led to lower weight loss rate of EG/APP at high temperatures and a significant increase of char residue at 800℃.The char formation between EG/APP and RPUF could be mainly contributed by APP.Compared with RPUF,the LOI of RPUF/EG/APP increased from 19.8% to 35.4% and the smoke density changed little.Compared with the RPUF/EG,RPUF/APP and RPUF/EG/APP,the more the amount and the higher thermal oxidation resistance of char residue,the higher the LOI is;the more compact of the residue surface,the lower the smoke released is.It was found that the heat release,smoke production rate and CO release rate of RPUF/TCPP were decreased significantly by the addition of EG/APP.The results embodied the advantages of a combination of chemical and physical intumescent flame retardants in the EG/APP system.关键词：Rigid polyurethane foam;Intumescent flame retardancy;Thermal degradation;Expandable graphite;Ammonium polyphosphate
- 73
- |
- 31
- |
- 9
发布时间：2021-03-19 - 摘要：Three kinds of polyisopropylacrylamide hydrogels (HNB) with 5~80 m of pore size were prepared by using surfactants Brij 52/56/58 with same hydrophobic alkyl chain C16H33 and different hydrophilic poly(ethylene oxide) (PEO,(CH2CH2O)n=2,10,20) segments as template.The results show that the hydrophobicity increases with decreasing n values.The Brij aqueous solutions with different n values show clear liquid crystal texture at a concentration of 15 wt%.At t=4 and 7 min,the transmittance of HNB58 and HNB56 pre-polymerized liquids decreases to 3.3~3.5.However,the transmittance of HNB52 pre-polymerized liquid keeps at 3.5 throughout the reaction time.The HNB58 hydrogel using Brij 58(n=20) as template shows numerous pores,and the size is 5~10 m.The HNB52 hydrogel using Brij 52(n=2) as template shows layered pore structure,and the maximum swelling ratio is 6.9 g/g.The HNB56 hydrogel using Brij 56(n=10) as template presents honeycombed state,having largest pore size from 40 to 80 m.In addition,the maximum swelling ratios of HNB56 is 7.9 g/g,and water loss rate exceeds 80% at 37℃ and 20 min.Since the template action of Brij,the volume phase transition temperature (VPTT33℃) of HNB hydrogels keeps almost the same in spite of the difference of n value,but the endothermic peak area becomes wider with increasing n value.关键词：Hydrogel;N-isopropylacrylamide;Template;Surfactant;Temperature-sensitivity
- 16
- |
- 11
- |
- 2
发布时间：2021-03-19 - 摘要：SBA-15 was synthesized by hydrothermal method,and modified with silane coupling reagents vinyl triethoxylsilane (KH-151),-glycidylpropyltrimethoxysilane (KH-560) and -methacryloxypropyl- trimethoxysilane (KH-570),respectively.Then different types of modified mesoporous sieves (M-SBA-15) were used as microreactors which were loaded with methyl methacrylate and initiator in toluene.Mesoporous channels were covered by PMMA in the form of thin coating via solution polymerization.M-SBA-15,PMMA/M-SBA-15 composites and PMMA polymerized in the channels were characterized by X-Ray diffraction (XRD),N2 adsorption/desorption,gel permeation chromatography (GPC),1H-nuclear magnetism resonance spectrum (1H-NMR),Fourier transform infrared spectra (FTIR),thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC).The results showed that modified mesoporous sieves and parts of the composites still retained the basic features of order mesoporous materials.Compared with SBA-15,BET surface areas,pore size and pore volume of both the modified mesoporous sieves and corresponding polymer composites decreased obviously.This confirmed that PMMA was loaded into the mesoporous channels.Molecular weight of PMMA in the channels of the mesoporous sieves was ten times more than that of traditional PMMA via solution polymerization.In addition,thus prepared PMMA exhibited higher initial thermal temperature,and glass transition temperature (an increase of 9~11 K) due to the little weak bonds formation and higher molecular weight.Furthermore,KH-151 modified SBA-15 loaded the highest PMMA content,and the PMMA possessed the highest molecular weight and Tg.关键词：Mesoporous sieve;Composites;Microreactor;Silane coupling reagents;Solution polymerization
- 43
- |
- 16
- |
- 6
发布时间：2021-03-19 - 摘要：A novel strategy of jet technology is developed to prepare rubber composites filled with carbon black.The carbon black aggregates were first dispersed into water by ultrasonic effect.Then in the high speed jet flow field,the carbon black suspension was dispersed into natural rubber latex.The carbon black particles were dispersed microscopically in the natural rubber latex by the turbulent tensile and shear force.High performance of natural rubber/carbon black composites is gained by latex compounding technique.The results showed that carbon black particles were uniformly dispersed into natural rubber by jet technology.And the interaction between carbon black was weakened,and the carbon-rubber interaction was enhanced.Compared to the properites of composites prepared by dry method,the tear strength and rebound of the composites prepared by jet technology were increased by 78% and 20%,respectively.The DIN abrasion loss of the obtained composites was decreased by 33%.The dynamic mechanical properties showed that the composites prepared by jet technology had lower loss factor at about 60℃.关键词：Jet technology;Natural rubber latex;Carbon black;Composites
- 25
- |
- 17
- |
- 1
发布时间：2021-03-19 - 摘要：11-Bromo-1-undecene,benzo-15-crown-5,methyl gallate and other reagents were used as raw materials,a kind of supramolecular compound named 2-(1-methylhydroxymethyl) [1,4,7,10,13-pentaoxabenzocyclopentadecane]-3,4,5-tris-[4-(10-undecen-1-oxo)benzyloxy] benzoate was synthesized.It was then grafted onto the surface of polyacrylonitrile (PAN) micro porous membranes by UV irradiation for preparing a new alkali-cation transport composite membrane.The grafting volume is 3.025 mg/cm2.ATR-FTIR,SEM and AFM were used to test the surface and the cross-section structure of the ion transport membranes.The results showed that the supramolecular compound could form columnar structure by self-assembly on the surface of PAN membranes as a dense skin.The ion transport property of the membrane was detected by a self-designed equipment.By comparison of non-functional material (acrylic acid) grafted membrane (CG membrane) and supramolecular compound grafted membrane (EG membrane) in transport experiments,the data showed that the new ion transport membrane is able to identify alkali cations such as Li+,Na+ and K+ and the order of transport capacity is Na+ K+Li+.关键词：Crown ether;Alkali metal;UV grafting;Ion-transport membrane
- 26
- |
- 12
- |
- 0
发布时间：2021-03-19 - 摘要：Six conjugated donor-acceptor copolymers were designed by choosing benzo[1,2-c:4,5-c']bis [1,2,5]-thiadiazole or [1,2,5]thiadiazolo[3,4-g]quinoxaline as the acceptor and thiophene,thieno[3,2-b]thiophene or dithieno[2,3-b:2',3'-d]thiophene as the donor unit.The electronic structure and properties of the designed copolymers were investigated systematically using the hybrid density functional theory method.The properties of the donor and acceptor moieties,especially the properties of the electron-donating and the electron-accepting ability,play a very important role in the geometric and electronic structures for the D-A copolymers.The theoretical study shows that the bridge bond length decreases regularly with an increase in the electron-accepting ability of electron acceptor,and increases regularly with an increase in the electron-donating ability of electron donor.In addition,the intramolecular charge transfer between the donor and acceptor moieties increases with an increase in the electron-accepting ability of acceptor and the electron-donating ability of donor.It is found that the band gap of the D-A copolymers is mainly controlled by the bond-length alternation along the main chain.The energy gap decreases with decreasing bond-length alternation.Namely,the band gap is decreased systematically with the decrease of bond-length alternation in the main chain.Among the designed copolymers,polymer p-BBT-TT is a very good candidate for an electrically conductive material due to its very small band gap (0.48 eV),large bandwidth and small effective mass of holes and electrons.关键词：D-A copolymers;Electron donor;Electron acceptor;Conductivity property;Molecular design
- 39
- |
- 17
- |
- 1
发布时间：2021-03-19 - 摘要：The urea formaldehyde polymerization controlled by using glyoxal was investigated.The sizes of the resin microspheres were in the range of 1.0~14 m,and the size range was 6.5~9.0 m in the presence of glyoxal.Sizes and morphology of the resin microspheres could be adjusted or improved with altering the aldehyde amount or glyoxal ratio in the reaction.Addition of glyoxal or increment of its ratio in the reaction significantly extend the induction time of precipitation (more than 25% longer).Infrared and XRD analyses show that the increment of both the aldehydes or the formaldehyde proportion can reduce the crystallization characteristics of polymers.Glyoxal is able to adjust the nucleation of urea formaldehyde resin or the growth of the primary particles,it was considered that the glyoxal covered the polymer surface or the active sites,limiting the diffusion of urea formaldehyde.The average size of silica microspheres prepared under the presence of glyoxal is only 20% of that of their precursor hybrids.A radial silica content gradient in the hybrid microspheres was suggested,which might result from the rate differences between silica hybridization and urea formaldehyde resin polymerization.关键词：Urea formaldehyde resin;Microsphere;Glyoxal;Hybrid;Silica
- 34
- |
- 10
- |
- 1
发布时间：2021-03-19 - 摘要：The galactosylated chitosan (GC) was synthesized by the reaction of the amino group of chitosan and carboxyl group of lactobionic acid under the activation of 1ethyl3-(3dimethyllaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide sodium salt (NHS).Subsequently,thermo-sensitive galactosylated chitosan-graft-poly(N-isopropylacrylamide) (Gal-CS-g-PNIPAm) hydrogels were prepared via free radical polymerization method.The chemical composition and structure of the novel copolymer obtained were characterized by Fourier transform infrared spectroscopy (FTIR),X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM),respectively.Thermo-sensitive feature of the hydrogel was studied by measuring its swelling ratio and contact angle.The results showed that Gal-CS-g-PNIPAm hydrogels exhibited good temperature response.HL-7702 cell behaviors such as proliferation,detachment and cell transfer were carefully investigated via cell culture on the surface of Gal-CS-g-PNIPAAm hydrogels in vitro. The results indicated that Gal-CS-g-PNIPAAm hydrogel exhibited a good biocompatibility.HL-7702 cells cultured on this hydrogel surface proliferated better than on the PNIPAAm hydrogel.Besides,HL-7702 cells could spontaneously detach from the surface of the Gal-CS-g-PNIPAAm hydrogel by lowering the temperature below the LCST (32.5℃),and the detached cells showed less damage than those detached by enzymes from TCPS.Meanwhile,cells detached from Gal-CS-g-PNIPAAm hydrogel showed higher viability than those from the PNIPAAm hydrogel,suggesting that introduction of GC monomer to PNIPAAm hydrogel evidently improved the activity of the detached cells.
- 33
- |
- 17
- |
- 2
发布时间：2021-03-19 - 摘要：Microwave treatment was used to cut off the three-dimensional structure of waste rubber powder(WRP),which increased the swelling degree of WRP in organic solvent.Then WRP modified by microwave treatment was immersed in tetraethoxysilane.During hydrolysis and condensation reaction process,SiO2 network was in situ generated on the surface of WRP by sol-gel method,which prepared modified waste rubber powder(MWRP).Natural rubber (NR)/MWRP composites were prepared by NR blended with MWRP.The properties of NR/MWRP composites were investigated.Thermogravimetry,differential scanning calorimetry and mechanical properties analysis showed that the best microwave treatment time was 20 s.The NR/MWRP composite owned the good mechanical properties,due to the improvement of compatibility between NR and WRP after microwave treatment and the reinforcement effect of in situ generated SiO2 particles.Si69 which prevented SiO2 particles aggregation and improved the dispersion of SiO2 particles was added to the rubber matrix.With Si69 content increased,the mechanical properties of NR/MWRP composites further improved and the Payne effect decreased.The storage modulus increased with increasing frequency during frequency sweep.The result of temperature sweep showed that with temperature increased,the aggregation of SiO2 particles increased and NR/MWRP composites exhibited the aging phenomenon.To improve the aging resistance properties of NR/MWRP composites,N,N-m-phenylene bismaleimide (BMI) as an antioxidant was added.BMI compensated for the lost crosslinking bonds during rubber aging process and improved the interfacial compatibility between NR and WRP by Diels-Aider reaction,which increased the aging resistance properties of NR/MWRP composites.关键词：Modified waste rubber powder;Composite;Mechanical properties;Aging resistance properties
- 47
- |
- 12
- |
- 1
发布时间：2021-03-19 - 摘要：The feasibility of employing Diels-Alder reaction for improving the grafting efficiency and controllability of poly(ethylene glycol) (PEG) towards chitosan (CS) was evaluated.Diene-capped PEG (PEG-diene) was conveniently obtained through thio-acrylate reaction between furfuryl mercaptan and poly-(ethylene glycol) methyl ether methacrylate (PEGMEMA).By using sodium dodecyl sulphate-chitosan complex (SCC) as an organo-soluble precursor,the dienophile,(N-(2-carboxyethyl)maleimide),was regioselectively conjugated to the hydroxy groups of chitosan backbone through conventional coupling method.Sodium dodecyl sulphate (SDS) was then removed from the conjugate simply by precipitating the reaction solution into tris(hydroxymethyl)aminomethane(Tris) solution to give the chitosan intermediate carrying dienophile moieties (CS-dienophile).In situ 1H-NMR was further used for studying the Diels-Alder reactions between CS-dienophile and PEG-diene.It was found that PEG could be grafted onto chitosan backbone in aqueous media under mild conditions.In addition,the PEG grafts could be detached from the graft copolymers at high temperature through retro Diels-Alder reaction.关键词：Chitosan;Diels-Alder;Poly(ethylene glycol);In situ 1H-NMR spectroscopy
- 55
- |
- 21
- |
- 0
发布时间：2021-03-19 - 摘要：The styrene cationic polymerization with the CumOH/BF3 initiating system in presence of water was studied.The effects of concentrations of CumOH and water on monomer conversion,polymerization rate and molecular weight of polystyrene were also investigated.An exhaustive mechanistic study of the styrene cationic polymerization in presence of water was proposed by molecular simulation and analyzing terminal structure.It is found that cationic polymerization of styrene exhibits controlled characteristic when [H2O] 0.11 mol/L; the content of water in solvent has no significant influence on rate of polymerization reaction,the conversion of monomer and molecular weight.However,cationic polymerization cannot be processed under a high excess of water ([H2O] 0.11 mol/L).On the basis of calculation results of activation energy,CumOH/BF3 initiating reaction is easier to proceed comparing with CumOH/H2O initiating reaction,which is found to be in line with the experimental results.The initiation reaction of CumOH/BF3 proceeds via activation of CO bond of ComOH to give active spieces.The water may serve here as a reversible chain transfer agent not only providing control over the polymerization reaction,but also forming hydroxy terminal groups.关键词：Controlled cationic polymerization;Styrene;Water-tolerant initiating system;Molecular simulation
- 72
- |
- 18
- |
- 1
发布时间：2021-03-19 - 摘要：The freezing-thawing cyclic (FTC) treatment was applied to assist destroy the compacted crystal structure and hydrogen bonding interactions in chitin (CH).It finally made chitin instantly dissolved in 8 wt% NaOH/4 wt% urea aqueous solution,subsequently a transparent homogeneous alkaline chitin solution was successfully obtained.The alkaline chitin solution was directly mixed with the initiator (ammonium persulfate,APS),the water-soluble monomer (acrylic acid,AA) and the crosslinker (N,N'-methylenebisacrylamide,MBA),then synthesis of chitin-g-poly(acrylic acid) superabsorbent polymers (SAP) was carried out in a thermostatic water bath by static solution polymerization method.The SAP was simply prepared by grafting the sodium polyacrylate chain onto the chitin backbone.The variety of factors that may affect the water absorption capacity and the yield of products were investigated,including the amount of AA,NaOH,MBA and APS,the reaction temperature,as well as the reaction time.The yield of the polymer synthesized under the optimum conditions was 85%.It can absorb 1251,455,84 and 77 gg-1 distilled water,running water,normal saline and artificial urine,respectively.Furthermore,the samples were preliminary characterized by Fourier translation infrared spectroscopy (FTIR) and X-ray diffraction (XRD).Results showed that the graft copolymerization reaction occurred between chitin and acrylic acid,rather than a simple physical blending of chitin and sodium polyacrylate.关键词：Chitin;Graft copolymerization;Freezing-thawing-cyclic treatment;Three-dimensional net structure
- 47
- |
- 20
- |
- 6
发布时间：2021-03-19 - 摘要：Poly(lactic acid)/poly(acrylic acid) blends (PLA/PAA) were prepared by melt blending.The hydrogen-bonding between PLA and PAA was analyzed by Fourier transform infrared spectroscopy (FTIR).The rheological properties,thermal behaviors and the stability of PLA/PAA blends were also investigated by dynamical rheological test,differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).The FTIR results indicated that the hydrogen-bonding interaction was existed in PLA/PAA blends between the oxygen atom of carbonyl (C＝O) on PLA and the hydrogen atom of carboxyl acid groups (COOH) on PAA.The rheological behaviors and cold-crystallization behaviors of PLA/PAA blends were changed with the contents of PAA,because the formation of the hydrogen-bonding in PLA/PAA blends was influenced by the contents of PAA.Meanwhile,the hydrogen-bonding networks were also affected by the heating history that the blends underwent.When the content of PAA was lower than 5 wt%,PLA and PAA was partially miscible,which was favorable to the formation of hydrogen-bonding networks between PAA and PLA chains.And the formed hydrogen-bonding networks can partially decrease the effect of plastification of PAA on the viscosity of the blends.However,when the content of PAA was greater than 5 wt%,the phase separation of melt PAA and PLA became serious,which counteracted the formation of hydrogen-bonding.关键词：PLA;PAA;Hydrogen-bonding;Rheological behavior;Crystallization behavior
- 66
- |
- 24
- |
- 2
发布时间：2021-03-19 - 摘要：pH-responsive microgels are cross-linked polymer colloids that swell when the pH approaches the pKa of the particles.They have potential application for injectable gels for tissue repair.They can undergo volume phase transition as a function of pH and concentration.However,a major drawback of such materials is the lower mechanical strength.Pre-emulsion technology was used to prepare the pH-responsive poly(methyl methacrylate-co-methacrylic acid-co-2-hydroxyethyl mthacrylate) (P(MMA-co-MAA-co-HEMA) microgels.The morphology,particle size as well as the swelling ratio were investigated by transmission electron microscopy (TEM) and dynamic light scattering (DLS).The TEM data showed the number-average size of the microgel particles was about 90 nm when the mole fraction of MAA was 25%,numbered G(HEMA-25) or G(MAA-25).When keeping the mass of MMA and HEMA the same,the particle size increased with the increasing of the MAA content.The maximum swelling ratio (q) of G(MAA-25) can be up to 1371.The microgels exhibit good pH responsibility and swelling properties.Fluid-to-gel phase diagrams for the G(HEMA-25),G(HEMA-16) and G(HEMA-4.5) dispersions were determined as a function of concentration (cp) and pH using tube-inversion measurements.The results showed that the critical minimum concentration (cp,min) increased and the critical maximum pH (pHc,max) decreased when gelatinization occured.The storage modulus of the gelled dispersions was investigated by using rheometry.The results show that storage modulus of gels increases with the increasing of HEMA contents.Because hydrophilic hydroxyl groups of HEMA may increase the hydrogen bond sites,which not only improve mechanical properties of microgels,but also make the network structure more stable.The storage modulus also depends on the MAA content.The storage modulus increased when the MAA mole fraction increased from 4.5 mol% to 10 mol% and then decreased.The storage modulus decreased with increasing temperature.When the mole fraction of MAA was 25% based on the total monomer and the concentration of G(HEMA-25) was 15 wt%,the storage modulus of colloidal gel reached 20000 Pa at scanning frequency ()=100 rad/s.关键词：Pre-emulsion technology;pH-responsive microgel;Phase transition;Storage modulus
- 31
- |
- 11
- |
- 3
发布时间：2021-03-19 - 摘要：Based on a surface initiated graft-polymerization method,a novel surface- molecular imprinting technique is designed and founded.The coupling agent -aminopropyltrimethoxysilane (AMPS) was bond onto the surface of silica gel particles,and amino groups were introduced onto the surfaces of silica gel particles,obtaining the modified particles AMPS-SiO2.In aqueous solution,the molecules of the anionic monomer sodium styrene sulfonate (SSS) were first combined around pirimicarb molecule (a pesticide) as the template molecule by right of strong electrostatic interaction.A redox initiating system was constructed by the amino groups on AMPS-SiO2 and ammonium persulphate in the solution,and free radicals were produced on the surfaces of silica gel particles.These free radicals initiated the monomer SSS and the crosslinker N,N'-methylene bisacrylamide (MBA) to be graft-copolymerized and crosslinked,and the surface-imprinting of pirimicarb molecule was realized.After removing the template molecules,pirimicarb molecule surface-imprinted material MIP-PSSS/SiO2 was obtained.Propoxur,which is another pesticide and its chemical structure is similar to that of pirimicarb to a certain degree,was used as a contrasting substance,and both static and dynamic methods were adopted to study the molecular recognition character and the binding property of MIP-PSSS/SiO2 for pirimicarb molecule.The experiment results show that MIP-PSSS/SiO2 have specific recognition selectivity and excellent binding affinity for pirimicarb molecules, and its selectivity coefficients for pirimicarb molecules with respect of propoxur molecules is 9.373,displaying high molecular recognition selectivity and excellent combination ability for pirimicarb.关键词：Surface molecular imprinting;Surface-initiated graft-polymerization;Sodium p-styrenesulfonate;Pirimicarb;Molecular recognition
- 33
- |
- 11
- |
- 1
发布时间：2021-03-19
Research Article
- 摘要：Laponite/polyurethane nanocomposites were successfully prepared by following two steps:(1) solvent-exchange approach to efficiently exfoliate Laponite into N,N-dimethyl acetamide (DMAC) solvent; (2) under ultrasound insert Laponite into polyurethane macromolecules.The structure and properties of the resulting nanocomposites were characterized by transmission electron microscopy (TEM),atomic force microscopy (AFM),thermogravimeric analysis (TGA),differential scanning calorimetry (DSC),thermodynamic mechanical analysis (DMA) and tensile testing.The results of TEM and AFM indicated that the most of Laponite was fully exfoliated into individual layers and uniformly dispersed in the polyurethane matrix.The Laponite platelets preferentially reinforce the hard segments or micro-domains of polyurethane because of the similar characteristic dimensions of Laponite and hard micro-domains and the hydrogen bond interaction,which was also further confirmed by DMA and DSC.The tensile testing results showed that the incorporation of Laponite into PU gave rise to significant improvements in mechanical properties,including tensile modulus,tensile strength and ultimate elongation.The hierarchical order induced by the addition of discotic Laponite platelets creates a percolated network that significantly improves the stiffness and toughness of the nanocomposites without reducing their extensibility.关键词：Polyurethane;Laponite;Nanocomposites;Solvent-exchange approach;Ultrasound
- 44
- |
- 17
- |
- 3
发布时间：2021-03-19
Research Bulletin
- Postal code：100190
- Tel：010-62588927 Email：gfzxb@iccas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备05002797号-8
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0