最新刊期
卷 ， 期 2 ， 2004
- 摘要：It is proposed that the overall free energy of a polymer solution has three fundamentally different types of contributions,i．e．the translational,the configurational and the thermal correction paris The second and the third pans have the additive properties for segments and can be calculated by path integral method with the introduction of a new concept of effective concentration．Taking the volume fraction as the effective concentration,one obtains the Li- Zhao theory of polymer solutions reposed previously．The results calculated by the present theory match the spinodals data of PS/cyelohexane systems with different molecular weights much better than those based on the Flory-Huggins theory．
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发布时间：2021-03-19 - 摘要：Nanocomposites based on ethylene-propylene-diene rubber(EPDM) and montmorillonite have been prepared via a melt process by using two vulcanization systems：a sulfur-accelerator system and a peroxide curing agent DBPH The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that,the rubber molecules were found to be intercalated into the galleries of the organophilie montmorillonite (OMMT),and the silicate layers were exfoliated and dispersed uniformly in the rubber matrix of the nanocomposite cured bv the sulfur-accelerator system,but the silicate layers were stacked and existed in the form of intercatated structure in the nanocomposite cured by the peroxide agent DBPH The exfoliated nanoeompesites were was opaque and had better mechanical properties than the intercalated ones which were semi-transparent The two kinds of curing systems had different curing behavior evaluated by the Flory-Rehner equation The vulcanization time (t90) was prolonged,and the maximum-minimum torque (MH-ML) decreased with increasing of OMMT content．and the EPDM become less erosslinked in the presence of OMMT for nanocomposites cured by sulfur curing system However,the corresponding values of the nanoeomposite cured by peroxide agent DBPH did not change obviously with the OMMT content.
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发布时间：2021-03-19 - 摘要：Electrochemical polymerization of the N-substituted pyrrole monomer,methyl (S)-(+)-2-(1H-pyrrol-yl) propionate in a chiral medium with (S)-(+)-camphor-10-sulfonic acid ((S)-(+)-CSA) or (R)-(-)-camphor-10-sulfonic acid ((R)-(-)-CSA) The obtained polymer films were characterized by cyclic voltammograms (CV),X-ray photoelectron spectroscopy (XPS),infrared,Raman,circular dichroism (CD) spectroscopies and scanning electron microscopy (SEM) The enantioselective recognition properties of polymer were also investigated in the presence of enantiomers of eamphorsulfonic acid as supporting electrolyte and doping agent Chiral alkyl N-substituted polypyrrole micro-ribbons were generated electrochemically and stand upright on the working electrode surface．The ribbons have alength of 100～200μm．a width of 20～50μm and athickness of 3～5μm．
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发布时间：2021-03-19 - 摘要：Polystyrenes (PS) with α-bromoethyl groups (PS-CH(CH3) Br) and bromobenzyl groups(PS-CH(Ph) Cl) have been successfully prepared and the former with low substitute degree was used to initiate ATRP of n-butyl aculate (MA)．In order to avoid the crosslinking reaction during the preparation,the following steps were adopted：the acetylation of PS with acetyl chloride,the reduction of acetylated polystyrene(PS-COCH3) with NaBH4, the esterification of α-hydroethylated polystyrene (PS-CH(CH3)OH) with acetyl anhydride and the bromination of α-acetoxylethylated polystyrene(PS-CH(CH3)OCOCH3) with HBr.As for PS-CH(Ph)Cl,PS-CH(Ph)OH was directly chlorinated with SOCl2 Haloalky polystyrenes and the intermediates were characterized by FTIR,1H-NMR,13C-NMR and GPC and their substitution degrees were determined from the integral height of phenyl protons at δ6.54 and that of the corresponding characteristic proton．All the results indicated a complete conversion of different substitute groups in the preparation process Graft polymerization of butyl acrylate (BA) was carried out and gave out poly (styrene-g-butyl acrylate) successfully using PS-CH(CH3) Br with low substitution degree as the ATRP macroinitiator in conjugation with CuBr and bipyridine at low monomer conversion．
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发布时间：2021-03-19 - 摘要：Two kinds of β-cyclodextrin(β-CD)-acrylic monomers,β-CD-3-A and β-CD-6-A,carrying the acryl groups were synthesized relying on their reactivity of different hydroxyl groups in cyclodextrin. 13C-NMR spectra indicated that,for β-CD-3-A,acylation occurs at C-2 and C-3 positions of β-CD,and for β-CD-6-A,the acylation occurs at its C-2 and C-6 positions．Two functional hydrogels were synthesized by copolymerization of β-CD-3-A and β-CD-6-A with N,N-dimethylaminoethyl methacrylate (DMAEMA) using a redox initiator svstem in aqueous solutions．The hydrogels were characterized by FTIR and elementary analysis．The equilibrium swelling experiments show that the hydrogels possess pH-,ionic strength and thermo-sensitivities．However,due to the difference of monomer structures,the physical properties of the two hydmgels．especially their swelling behavior in response to the extemal stimuli,exhibit certain difference It is reasonable to assume that the structure of β-CD-3-A in its hydrogel is more favorable to initiate hydrophobic interactions between dimethylaminoethyl segments and hydmphobic caves in β-CD,as a result,reducing the hydmgel’s transition points．It can also be observed that the transition regions for both hydrogels shift to lower temperatures with the increase in contents of β-CD-3-A or β-CD-6-A．
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发布时间：2021-03-19 - 摘要：The influence of suflace grafting nlodified nano-silica on the isothermal and non-isothermal crystallization kinetics of isotaetic polypropylene (IPP) was investigated by DSC The silica panicles were pre-grafted with styrene,methyl methacrylate,ethyl acrylate and butyl acrylate,respectively．The experimental results show that the addition of nano-silica into PP has an obvious nucleating effect on the crystallization of PP,resulting in higher crystallization temperature and lnehing point,as well as higher crystallinity and the overall rate of crystallization,but lower crystalline regularity．The surface grafting treatment of the nanopartieles promotes the nucleating effect due to the increased miscibility between the particle and the matrix The nucleating effect of the particles is also related with their dispersion state in the polymer matrix．The melting behavior of neat PP is different to that of the PP filled with nano-siliea．The later has a more uniform crystal structure because the fillers act as nucleates．However,a faster isothermal crystallization process of the PP filled with nano-silica results in a lower equilibrium melting point．implying that the crystalline structure is less perfect in this ease．
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发布时间：2021-03-19 - 摘要：pH-sensitive hydrogels based on carboxymethylchitosan (CMCTS) were synthesized by using glutaraldehyde as cross-link agenl The effects of the degree of deacetylation of CMCTS and the dosage of erosslinker on the swelling behaviors of hydrogels have been studied The results show that the two factors related above regulate their swelling behavior At pH=3.0,the hydmgel shfinked most while swelled at pH：1 0,5．0,7．4,9 0．In general,the swelling ratio (SR) of this hydrogel in alkaline solution is much larger than that in acidic solution．The release behavior of salicylic acid(SA)entrapped in the hydrogels was of distinctly difference with the changes of pH value of loading medium and the semidiameter of the hydrogels．The release of salicylic acid in CMCT hydmgel in the medium of pH=1.0 was much quickerin pH=7.4,12.0,andtherelease speed and release ratioincrease with the partical size．
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发布时间：2021-03-19 - 摘要：Copolymer latex containing perfluorooctylethyl methacrylate was prepared by emulsion polymerization using sodium dodecyl sulfate SDS and OP-10 as emulsifier The copolymer was characterized by using DSC、FT-IR and 1H-NMR techniques Surface properties of the copolymer film were measured by contact angle measurements (JZHY-180) The results show that the surface free energies of copolymer films decrease drastically with increasing the concentration of FMA8．and can reach 19.74 mJ/m2 when the concentration of FMA8 used in copolymerization increases to 25 wt％．X-ray photoelectron spectroscopy (XPS) was used to investigate the atomic compositions of the surface of eopolymers．It was found that the content of fluorine on the surface of copolymers is higher than the value calculated according to the feeds．Our investigation verified that groups containing fluorine tend to enrich at the copolymer-air interface．Through annealing treatment,the content of fluorine on the surface nf copolymers was found to increase,which resulted in fudher decrease of surface free energies．
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发布时间：2021-03-19 - 摘要：Most materials will shrink or expand laterally when stretched or compassed,i. e．they have positive Pnisson ratios,but materials with negative Poisson ratios will undergo lateral expansion when stretched longitudinally and become thinner when compressed．And materials exhibiting this novel and counterintuitive behavior,now known as auxetic materials,have been successfully fabricated with many new applications Currently,molecular auxeties,namely auxetic materials at the molecular level,have become the most exciting endeavor in the development of auxetic materials．In this paper,as new alternatives to the making of molecular auxetics,several typos of centipede- like linear polymem both with single and double legs on the side chain,single-arrow-like,double-arrow-like organic compounds were designed as building blocks for self-assembling into auxetic network structures through hydrogen bonds．The second derivative method is used to cateulate Poisson ratios after doing molecular mechanics (MM) optimization The results show that all these self-assembly networks can be arranged as inverted honey-comb like streetures and their Poisson’s ratios in at least one plane are negative and even the self assembly of small molecules with special architecture may achieve auxeticity in some cases．Compared with many approaches proposed so far．that of the self-assembly of both single polymem and single small molecules into molecular auxetics reported here is quite novel．It provides a new route to synthesize molecular auxetics,which should be much easier than that for synthesizing two-dimensional cross-linked auxetic networks．Yet its successful realization requires great experimental efforts.
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发布时间：2021-03-19 - 摘要：In the curing reaction processing of BOZ-A/vermiculite nanocomposites intercalated with polybenzoxazine (bisphenol A type) precursor (BOZ-A),the acidic onium poton on the organophilic vermiculite surface has not emerged catalytic effect on the ring-opening polymerization of BOZ-A．It may be indicated that different retarding effects took place while different kinds of dispersed status(“intercalation”and/or“exfoliation”) of vermiculite layers were forming,which were correlative with the content of vermiculite in resin matrix As the content ol vermiculite is about 3 wt％,the curing retardance is serious,compared with that of pristine BOZ-A,the i>tgel and the curing activation energy (Ea) of BOZ-A in the nanocomposites increased 7min and 8 kJ/mol,respectively,and the curing enthalpy (△Hd) decreased by 14J/g．As a result,the cure-degree of rsin decreased by 7％～10％．With the increase of vermicalite content,the curing retardance becomes not obvious．
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发布时间：2021-03-19 - 摘要：Gas chromatograph-mass spectrograph was used to analyze the decomposition products of a new type of cyclic triperoxy initiator(3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane,TETMTPA) in ethyl benzene．The major compounds before ethyl benzene are carbon dioxide and aliphatie compounds,such as ethane,propane,butane,ethanol,acetic acid,methyl ethyl ketone,methyl acetate and ethyl acetate,while the compounds after ethyl benzene are all aromatic,such as styrene,isopmpyl benzene,isobutyl benzene,2-phenyl ethanol,methyl phenyl ketone and 2,3-diphenyl butane The decomposition mechanism of TETMTPA was proposed from the structure of these compounds．It is considered that there are three pathways for the decomposition of the initiator：the main one is the homolysis of O一O bond．and the other two are the cleavage of C—C and C一O bonds due to the effect of p-electron on the adjacent radical．In considering the cage effect,it is proposed that the aliphatic compounds from the coupling of free radicals in the cage,while the aromatic compounds form via the chain transfer of the radicals to ethyl benzene outside the cage．In comparison with di-tert-butyl poroxide as a reference initiator．the polymerization rate of styrene initiated by TETMTPA is slower owing to its lower decomposition rate constant and initiator efficiency in the case of same equivalent of peroxy group,but the molecular weight of polystyrene initiated by TETMTPA is higher due to the propagation via di-radical The mechanism of initiation is validated through 1H-NMR spentra and DSC analysis of PS initiated by TETMTPA Based on these principles,polystyrene with hisher molecular weight and considerable polymerization rate may be prepared commercially by using muhifunetional initiators．
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发布时间：2021-03-19 - 摘要：By using X-ray photoelectron spectroscopy and IR spectroscopy．a series of coordination units of methyl acrylate (M) and 2-vinyl pyridine(V) copolymer rhodium complexes were studied in comparison with those of methyl acrylate (M) and 4-vinyl pyfidine(V’) copolymer rhodium complexes．The influence of the micmstmctures of their active centers and reaction temperature on their catalytic activity for methanol carbonylation was investigated by well-directed experiments．It has been found that the complexes containing methyl acrylate (M) and 2-vinyl pyridine (V) copolymer ligands exhibit much higher catalytic activity than those of methyl acrylate (M) and 4-vinyl pyridine (V’) copolymer rhodium complexes on carbonylation of methanol．It is suggested that the 2-substituted vinyl pyridine possesses the favored catalytic mierostructure for such reactions．These experimental observations provided theoretical and practical incentive to fuaher investigation．
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发布时间：2021-03-19 - 摘要：γ-Benzyl-L-glutamate was synthesized by the reaction of L-glutamate and benzyl alcohol．N-Carboxy-γ-Benzyl-L-glutamate anhydride (NCA) was synthesized from γ-benzyl-L-glutamate and tfiphosgen．MPEG was used to prepare amine-terminated poly(ethylene glycol) monomethyl ether(MPEG-NH2),which was used to initiate NCA ring opening polymerization and produce poly (ethylene glycol) monomethyl ether/poly(γ-benzyl-L-glutamate) (PMBG) diblock copolymers with various block contents and molecular weights．The structural characteristics of copolymers were attested by means of IR、1H-NMR、DSC and GPC measurements．The results showedthat products of NCA ring opening polymerization initiated by MPEG-NH2 were block copolymers．Their block contents and number-average molecular weights were calculated from 1H-NMR．The hydrophilicity of homopolymer poly(γ-benzyl-L- glutamate was improved by adding hydrophilie MPEG blocks．
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发布时间：2021-03-19 - 摘要：Copolymer of 1,1-dihydroperfluorooetyl acrylate (FOA) and acrylic acid (AA) was obtained in supercritical CO2(SC-CO2) Compared with the traditional methods,the yield ratio of FOA using SC-CO2 is increased at lower temperature,the reaction time is shortened from 24 h to only 4 h,and the products are easier to be treated．At the same time it was found that temperature played an important role in these reactions．The FOA monomer is more active than the AA monomer in low temperature(TT> 60.0℃) the activity of AA monomer improved greatly The viscosity of aqueous solutions of the copolylmers rises up dramatically with the increase of fluorocarbon content, and the viscosity of the eopolymets versus pH values shows a peak,both of results evidenced the hydmphobic association of macmmoleeules in solutions．
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发布时间：2021-03-19 - 摘要：A new emulsion polymerization process,in which water acted as the dispersed phase and the mixture of methyl methacrylate (MMA) and cyclohexane as the continuous phase,was applied to prepare PMMA resin．It showed that porous PMMA particles composed of aggregated primary particles were prepared by the new polymerization process．The size of these primary particles was smaller than that of the primary particles of PMMA resin prepared by MMA suspension polymerization in the presence of cyclohexane．According to the phase structure of the initial polymerization system．the solubility of PMMA in the mixture of MMA and cyclohexane and the variations of particle size distribution and morphology of PMMA resin,a particle formation mechanism of the new polymerization was pmposed,covering the formation and grouth of primary particles and their coagulation in the dispersed water droplets．
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发布时间：2021-03-19 - 摘要：Atomic transfer radical polymerization (ATRP) was used for the preparation of an amphiphilic di-block copolymer——polystyrene-b-poly(acrylic acid) (PS-b-PAA)．The structure and composition of the copolymer have been characterized carefully by 1H-NMR,IR and GPC In order to determine the critical concentration of polymeric micell formation (CMC) a dimethyl amino flavone derivative was used as a fluorescence probe for detection of the critical concentration of the copolymer in solutions．The morphology of polymeric micen formed was studied by electronic microscope．A clear transformation from nano-spherical to nano-wire has been observed．
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发布时间：2021-03-19 - 摘要：The main disadvantages of thermoplastic starch(TPS) are their retmgradation and unsatisfactory mechanical properties particularly under wet or dry environments．Formamide was used as an individual plasticizer to prepare thermoplastic starch (TPS) to overcome the facile retmgradation of polyols-plasticized TPS with good mechanical properties or the poor mechanical properties of urea-plasticized TPS with good retrogradation resistance By using scanning electron microscope (SEM) the native cornstarch granules wele proved to transfer to a continuous phase with out crystallinity after plasticization with formamide By theology tests,it was shown that formanfide made TPS less temperature sensitive than glycerol did in the processing temperature range of formamide-plasticized TPS (FPTPS) from 110℃ to 150℃ Thermal analysis reveals that glycerol-plasticized TPS (GPTPS) exhibits better thermal stability and FPTPS has a slightly lower glass transition temperature The effect of water contents on the mechanical properties of FPTPS and GPTPS was also studied．and FPTPS showed good ductility at water contents of 13％～35％．The maximal failure stress and strain were 3.9 MPa and 95％．respectively．At three typical environment conditions of RH=0.50％ and 100％,the influence of formamide and glycerol on the retrogradation of TPS was studied using X-ray diffractometry．It was found that compared to glycerol,formamide could effectively restrain the retmgradation at various humidities The property improvement of TPS by using formamide was ascribed to the formation of more stable hydrogen bonds between plasticizer molecules and the hydroxy groups of the starch．
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发布时间：2021-03-19 - 摘要：Polycarbosilane (PCS) is the precursor of SiC ceramic fibers,and oxidation-curing process of PCS fibers is an essential step of making Nicalon style SiC fibers．The oxygen introduced into PCS fibers seriously affects the mechanical proporties of SiC fibers at high temperature．In this paper,the probability whether PCS fibers can be thermal-cured without oxygen was investigated．It was found that a minimal degree of oxidation-curing of PCS fibers was necessary for their further thermal curing Under these conditions the oxygen content of fibers decreases,and their pmperties can be improved．The mechanism of thermal-curing of low degree oxidation-curing PCS fibers and the function of oxygen were investigated Results showed that the minimal degree of oxidation-curing was corresponding to a 9％ weight gain of PCS fibers．During the thermal-curing process,the Si-H of bonds PCS were mostly consumed and Si—CH2一Si structure Was formed；Si一OH was formed when a little oxygen was introduced into PCS fibers in the oxidation-curing process and may form Si—O—Si structure during further thermal-curing,making a protective layer on the surface of PCS fibers．
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发布时间：2021-03-19 - 摘要：Orientation of azo chromophores in electrostatic self-assembled multilayer films of four side-chain azo polyelectrolytes that contain azobenzene derivatives with different p-substituents was investigated by using polarized UV-Vis absorption spectroscopy．Influences of substituents on the orientation of the azo chmmophoms were discussed in detail The structural characteristics of these self-assembled films were further investigated．It was found that the homogeneous oriention tendency of azobenzene was a common phenomenon in the self-assembled films fabriemed by electrostatic layer-by-layer dipping process of the side-chain azo polyeleetrolytes and poly (diallyldimethyl armnonium chloride)：suhstituents that link to azobenzene have influences on the orientmion of azobenzene in self-assembled films,which could be attributed to charge interaction and dipolar interaction between the ehromophores and the polycation substrates．For those self-assembled muhilayers with H-aggregation．the effect of substituents on the orientation of azobenzene was also influenced by the H-aggregation．The results indicate that the orientation of azobenzene in self-assembled films can be effectively adjusted by selecting polyelectmlytes containing azobenzenes with different p-substituents．
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发布时间：2021-03-19 - 摘要：Thermal imidization of the polyamic acid derived from BPADA and BAPS was investigated mainly by GPC and FTIR equipped with an in-situ hot cell．The non-isothermal imidization was carried out in the temperature range from 100℃ to 300℃ with a multi-step heating program．Resalts indicated an initial dissociation of the amide bonds,producing anhydride and amine end groups,and the reduction in molecular weight and the embrittlement of the film．As the temperature was increased further,the above terminal functional groups recombined to increase the chain length and molecular weight．resulting in the toughness recovery of the film．The isothermal imidization included two steps of different reaction rates,afast stepfollowed by a slow one．Thatisto say a kineticinterrupttook place．A two-step first-order kinetics model was applied to the isothermal imidization,and the relevant parameters,such as k．E．and A,were obtained In addition,as the isothermal imidization was concemed,a new empirical formula was pmposed to correlate the degree of imidization at the kinetic interrupt point with the curing temperature,which sbowed a good agreement with the experimental date Moreover,the kinetic interrupt was explained based on both the conformation change and the effeet of free volume.
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发布时间：2021-03-19 - 摘要：The benzylated wood was liquefied using HCL as a catalyst and a mixed dibasic ester (DBE) as a novel liquefaction reagent,which has been applied extensively in coating industry because of its higher solubility and less toxicitv．Then the solution obtained reacted with different isoeyanates．Bv FT-IR and 13C-NMR analysis of the polyurethane resins prepared from liquefied benzylated cellulose．it was proved that the wood solution could be used as the polyols component to prepare polyurethane materials On the other hand,by measunng the free NCO content in each system of polyurethanes from the wood solution,the changes of active hydroxy numbers in the wood solution can be calculated in the presence of different isocyanates The results showed that isocyanates greatly stimulated the release of hydroxyl in wood,but the different structure and activity of isocyanates led to the different changes of hydroxyl in an order as follows：IPDI>HDI>TDI．In order to guarantee the resultant properties of polyurethanes materials．TDI and IPDI should be selected as the isocyanate component in the preparation of polyurethanes using wood wastes.
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发布时间：2021-03-19 - 摘要：In the process of preparing electrophoretic ink microcapsules by in-situ polymerization,oligomers instead of traditional prepolymers (hydmxymethyl urea and dihydmxymethyl Hrea) of urea,formaldehyde were used as monomers of reaction,because oligomers ale more likely to be adsorbed on the surface of oil phase droplets．The general problems of in-situ polymerization such as coagulating,sticking,coarse surface,low productivity eyc．have been solved The properties of viscosity and surface activity of urea-formaldehyde oligomers were studied,as well as their relationship with the encapsulation efficiency of mierocapsules．The electmphoretic ink micmcapsules were prepared successfully by this method．
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发布时间：2021-03-19 - 摘要：Effective interresidue contact energies for proteins in solutions are estimated from the number of residue-residue contacts observed in crystal structures of globular proteins(http：//www．rcsb．org/) by means of the Miyazawa-Jemiganm (MJ) interaction matrix．It is found that residues can be classified into three groups according tothe contact energles：hydrophobic residues (H),neutral residues (N),and hydrophilic residues (P) Here we develop a modified HP lattice model,i．e．a HNP lattice model．In this model,the contact Hanfiltonian is simply written asH=-∑iEsi-sjδ(rij,l)(Si=H,or N,or P) (4)Where EH-R=-5 59RT,EH-N=-3.68RT,EEH-P=-3.07RT,EN-N=-2.23RT,EN-P=-1.78RT,EN-P=一1.37RT,and rij is the distance between residues i and j. We first calculate the conformational properties of the native states of shon Drotein chains using 2-dimensional HNP lattice model and enumeration calculation method The distributions of various types of residue-residue contacts and three types of residues of the native states are discussed We also investigate the folding of the protein with a sequence of HHNHNPNHPPHPNPPHPHPPHHPHNH using the modified HP lattice model Here the sequence is selected at random The folded conformation is obtained in square lattice,and the folding energy is -64.89RT．Our calculation shows that the HNP lattice model may be more reasonable for simulation of the folding behavior of real proteins.
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发布时间：2021-03-19 - 摘要：The miscibility of blends of poly (acrylonitrile-vinylphenol)[P(An-VPh)],in which hydroxyls were introduced to tbe opposites sites of pbenolie rings of poly (acrylonilrile-styrene)[P(An-S)],with bisphenol-A pdycarbonate (PC) and tetramethyl bisphenol-A polycarbonate(TMPC) was studied．As a consequence．auseible svsteins could be obtained under the combination of the“intermolecular special interation”and the“intramolecular repulsive interaction”,due to the existing of hydroxyl groups in the copolymer of the blend system．The miscible blends were obtained only when the An eontem in the copolymer was between 12.3％ and 49.5％ mol in the fist pair．and O～58.9％ mol in the second pair The theoretical calculation and simulation based on the Flory-Huggins mean field theory were made,and the results agreed well with the experimental ones,from which χTMPC-VPh=一0.19 was obtained.
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发布时间：2021-03-19 - 摘要：An online,non-destructive test system,based on small angle light scattering (SALS) measurements,was presented and applied to the phase-size investigation of polyethylene/polyamide 1010(PE/PAl010) immiscible blends along the extruder during twin-screw extrusion At the same time,some specimens were sampled online and analyzed by use of scanning electron microscopy (SEM)．From SALS analysis．the phase size was characterized by the correlation length α,average chord length Lscatt and average diameter of dispersed phase,Dscatt according to the Debye theory Because the correlation length αc is related to the average particle size and the volume fraction both,αc is only suitable for representing particle size among blends with the same composition．Average diameter of dispersed phase Dscatt is suitable for representing the size of dispersed phase for discrete systems．Average chord length Lscatt,however,could represent the phase size for discrete or co-continuous systems among blends with the same or different compositions From SEM analysis the average chord length LSEM and average diameter of dispersed phase DSEM were also calculated according to their definition．The results of SALS and SEM ale in good agreement, which show that SALS online system can be a powerful method to investigate the phase size during twin-screw extrusion Both SALS and SEM show that the dispersed particle size becomes progressively smaller Moag the screw length．For the ukimate morphology of PE/PA1010 blends with different components (PA1010≤50％,volume fraction),the size of dispersed phases increases and the size of continuous phase decreases with the increase of the PA1010 component．At the composisions(PE/DA1010) of 60140 and 70/30,co-continuous phases occur．
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发布时间：2021-03-19 - 摘要：Theophylline crystal imprinted polymem capable of inducing theophylline crystallization in aqueous media were prepared by a photo-initiating approach with methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EDMA) as the cross-linker．SEM studies showed that the surface of the theophylline-imprinted polymer,after a thoroughly washing procedure with 0.1 mol/L HCl solutions,could well induce theophyiline crystallization process,when it was immersed in a saturated theophyHine solution for 24 h．On the contrary,the caffeine-imprinted polymer failed to show the same result under the given conditions．The subtle distinction in their molecular structures related to the imidazole ring might be one of the major reasons responsible to the observed results．The theophylline molecule could interact with the carboxyl of methacrylie acid via its imidazole ring as well as the neighboring carbonyl group in its pyrimidine part by hydrogen bonding and/or electrostatic interactions,while the caffeine molecule could not form the same bonds with the methacrylic acid due to the existence of its methyl displaced imidazole ring．
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发布时间：2021-03-19
Research Article
- 摘要：The grafting of maleic anhydride onto a granular polypropylene (PP) using supercritical CO2 as a solvent and swelling agent was studied to prepare granular PP-g-MAH polymers The factors affecting the graft degree of PP,such as the monomer content,initiator content,reaction temperature and reaction pressure were discussed The maximum graft degree of PP with MAH in supercritical CO2 medium was 5.23％ under the optimal reaction conditions at 125℃ and 15 MPa for 5 h．By using the superefitical CO2 technique the operation of grafting reaction and separation of products became simple and easy to deal with．The formation of PP-g-MAH grafting copolymer was evidenced by FTIR measurements An absorption peak at 1720.6 cm-1 assigned to the stretching vibration of carbonyl groups was observed．DSC results indicated that the grafting gave almost no influence of Tg values,but may increase the crystallinity of PP.
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发布时间：2021-03-19 - 摘要：A novel method for the patterning deposition of conducting polyaniline (PAn) on a transparency substrate was presented．A picture or a drawing was printed on a transparent film by a standard laser printer．and PAn was in-situ polymerized on it for three times．Then the transparency was souicated in toluene or benzene for 20s,the printed part was removed and a dupe reverse pattern appeared．In order to investigate the capability of patterning deposition,a dupe reversal of a laser printed photo Was produced,which was more difficult than line patterning (LP)．It showed that the detmlsofthe original photo werereproduced．althoughthe contrast was not so perfect duetothetransparence of the PAn film．It meant that the in-sau polymerization of PAn could produce rather complicated and delicate patterns,and was prospective to apply in the manufacturing of organic electronics,especially for some disposable plastics/papor electronics．The effect of HClO4,HCl and toluenesuffonate dopants on the quality of PAn film was studied．
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发布时间：2021-03-19 - 摘要：A novel polyelectrolyte PNANT functionalized with electron donor-aceeptor type azobenzene chromophores has been synthesized through post-polymerization azo coupling reaction and characterized by 1H-NMR．FTIR and UV-Vis spectroscopy．The degree of funetionalization (DF) of PNANT was 20％ measured by elemental analysis The degree of polymerization and its distribution were determined by GPC to be Xn=251 with a polydispersion index 1.53．A glass transition temperature of 119℃ was observed from DSC thermogram H-aggregation of azo chromophores of PNANT in spin-coated film and self-assembled film were detected from UV-Vis spectra,and the degree of H-aggregation of PNANT in the self-assembled film was found to be higher than that in the spin-coated film．Dichmism was optically induced in the spin-coated film and self-assembled film upon the irradiation of a polarized Ar+ laser beam at 488 nm．The orientational order parameter obtained was 0.15 for spin- coated film and 0.07 for the self-assembled film．The resulting dichroism detected by UV-Vis spectra exhibited long-terra stability．
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发布时间：2021-03-19 - 摘要：An azyl group of ethylene dianfine was protected by N-tert-butoxyearbonyl．The remaining azyl group then successively reacted with methyl acrylate,ethylene diamine and methyl acrylate again to afford the compound Boc-NH2-(B-COOCH3)4 3(AB4)．The ester groups and the Boc-end group of 3 were transferred to carboxylate 4 and azyl group 5 via hydrolyzation and deprotection respectively．The fan-shape dendron molecules with 16 exterior groups 6 were obtained by condensation of 4 and 5 in the presence of DCC The dumbbell-like dendrimer molecules 7 could expediently prepared by coupling the dendrons with two functional groups of hexanedioyl chloride The paper describes the synthesis procedures,reports the characterization results of FTIR、1H-NMR、13C-NMR and MALDI-TOF Comparing with the PAMAM dendrimers from the divergent method,the synthesized compounds possess accurate structures and few defections.
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发布时间：2021-03-19 - 摘要：Hyperbranched poly (ester-amine) with terminal amine groups was synthesized by Michael addition reaction between trimethylolpropanetriacrylate (B3 monomer) and pizine (A2 monomer) under molar ratio of 6:13 via a one-step procedure．It was further modified by stearyl chloride to form an amphiphilic hyperbranched polymer．The structures of these polymers were characterized by FT-IR．1H-NMR,DSC and GPC analyses．Due to the existence of interior secondary amines,the modified polymer can be used as phase transferring agent to extract methylic orange from water layer to CHCl3 layer．Both higher transferring capability and higher transferring rate were achieved at lower pH of the water phase The extracted dye in the organic layer can be further released to the water layer under a basic condition．A possible mechanism for extracting dye by amphiphilic hyperbranched polymer was suggested.
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发布时间：2021-03-19
Research Bulletin
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