最新刊期
卷 ， 期 6 ， 2002
- 摘要：The aim of this study is to prepare low loading electrical conductive polymer composites of polypropylene／graphite. The PP／graphite compounding powders were successfully prepared by pan-milling at ambient temperature．Their structure and properties were characterized by particle size analysis,SEM and XRD．The results showed that pan-milling realized pulverizing,dispersion and compounding of PP and graphite．Through 25 cycles pan-milling,PP and graphite powders imbedded each other and made into uniform PP／graphite compounding powders．PP／graphite powders were observed as strips through SEM. XDR spectra showed that pan-milling decreased crystallinity of PP from 56.16％ to 26.38％,and reduced crystallite dimension of PP and graphite,increased the interspaces of crystal face．The prepared PP／graphite compounding powders can be used for conductive composites．When graphite content is 10 wt％,the electrical conductivity of PP／YEP250 composites reaches 6.3×10-3 S·m-1,much higher than 7.1×10-16 S·m-1 of PP．Pan-milling is an effective way to prepare functional polymer based composites．
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发布时间：2021-03-19 - 摘要：Amphiphilic block copolymers have many unique physical and chemical properties,especially the strong self-assembling ability,because of the amphiphilic properties and microphase separation of their molecules. In this investigation,the amphiphilic block copolymers of acrylamide(AM) and styrene(St) were prepared in microemulsion medium．Two series of copolymers PAM-b-PSt were synthesized,one of them had variable composition,but an approximately constant molecular weight,and the other one had different molecular weight with an approximately constant composition．The composition of the copolymers was determined by ultraviolet spectrophotometry method,and the intrinsic viscosity of the copolymers from which the molecular weight of copolymers can be estimated relatively was determined by using an Ubbelohde viscometer．The association behavior of molecular chains of the amphiphilic block copolymer PAM-b-PSt in aqueous solution,its surface activity and solubilization ability were emphatically studied,and the effect of molecular composition and molecular weight on these properties was also investigated．The experimental result shows that the amphiphilic block copolymers PAM-b-PSt synthesized in microemulsion medium display some behavior of polymer surfacants．For example,because of the hydrophobic property of PSt blocks the molecular chains of PAM-b-PSt can form surface absorption on the surface layer of solutions resulting in an decreased surface tension of aqueous solutions,under hydrophobic interreaction the styrene blocks of PAM-b-PSt can form intermolecular and intramolecular micells in solution and the critical micell concentration of PAM-b-PSt is small．These micells can solubilize alkane substances,namely,the aqueous solution of PAM-b-PSt possesses solubilization ability for alkane substances．The higher the content of hydrophobic block sections is,the better the surface activity and solubilization ability of the copolymers are,and the smaller the molecular weight is,the better the surface activity and solubilization ability of the copolymers are．Obviously,because of the hydrophobic properties of PSt blocks the amphiphilic block copolymers synthesized in microemulsion medium have potential application prospects in enhanced oil recovery.
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发布时间：2021-03-19 - 摘要：The crystallization and morphology of poly(ethylene 2,6-naphthalate) (PEN) containing soium benzoate (SB) were investigated by means of differential scanning calorimetry (DSC),polarized optical microscopy (POM) and small angle light scattering (SALS)．It was revealed that SB may act as a chemical nucleating agent of PEN．It can decrease the surface free energy barrier toward nucleation and accelerate the crystallization rate of PEN at high temperature．Meanwhile,SB can improve the mobility of PEN chain,so the crystallization rate of PEN can also be increased at low temperature．The size of hedrites and spherulites,corresponding to the crystal morphology of PEN samples crystallized at high or low temperature,respectivdy,is reduced in the presence of SB．It is indicated that the nucleation rate of PEN is enhanced by SB．Furthermore,the obtained PEN spherulites become less perfect with the addition of SB.
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发布时间：2021-03-19 - 摘要：Dimethyl 2,6-naphthalate (DMN) and sodium of o-chlorobenzoate (SOCB) were used as model compounds to simulate the chemical reaction between poly(ethylene naphathalate) (PEN) and carboxylic acid alkali salt；and the reaction was studied by using DSC,polarized optical microscopy with a hot-stage (HPOM),Fourier transform infrared spectrometry(FTIR) and high performance liquid hromatograpby (HPLC)．By means of DSC and HPOM,the reaction between PEN and SOCB was also proved at high temperature．Therefore,the chemical nucleation mechanism of carboxylic acid alkali salts in PEN was proposed．Carboxylic acid alkali salt reacts with the ester linkages of PEN at high temperature and PEN ionic chain-ends were produced．The ionic chain-ends act as a true nucleating agent to improve the crystallization rate of PEN．
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发布时间：2021-03-19 - 摘要：Binding of cationic derivative of pyrene,pyrenemethylamine hydrochloride (PyMeA·HCl) to a polyanion,poly(2-(acrylamido)-2-methylpropanesulfonic acid) (PAMPS) in aqueous solutions was probed by the excimer fluorescence and simulated with a competitive binding equilibrium model．The relative emission intensity IE／IM of excimer to monomer displays a maximum with increasing PyMeA·HCl concentration and the binding stoichiometry for saturation binding is determined from the concentrations of PAMPS and PyMeA·HCl at the maximum．IE／IM obviously decreases with adding sodium chloride of about 10-4 mol／L into the solution due to the competitive binding of sodium and probe cations．In our binding equilibrium model,the binding of different cations on anionic polymer is considered as an equilibrated reversible process governed by the equilibrium constant．IE and IM are assumed to be proportional to the probe concentrations forming excimer and remaining individually,respectively．Calculated bound probe concentration cDL increases with total probe concentration cDO before binding saturation and the increasing rate becomes higher with higher value of the equilibrium constant．The simulated IE／IM,as the above probe concentration ratio,also shows a maximum with increasing cDO the same position as experimentally observed．By assuming a comparable binding equilibrium constant for the cation of added salt,the abrupt decrease in IE／IM observed with adding salt is reproduced by the simulation．These results indicate that the competitive binding of ionic pyrene probe on polyelectrolyte can be reasonably described by the binding equilibrium model.
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发布时间：2021-03-19 - 摘要：4,4′-Dicarboxy-1,6-diphenoxy hesane was synthesized,having a m．P．of 303.0℃,and its hydrogen bending associated complex with equal molar 4,4′-bipyridine exhibited thermally stable supramolecular liquid crystal behavior evidenced by DSC,polarized optical microscopy (POM) and FTIR studies．The DSC transition peak temperatures were 209.5,234.6,246.2℃ in the 2nd heating and 243.2,211.9,173.9℃ in the 1st cooling respectively,and the transition peak temperatures were reproducible during different thermal cycles except a little difference in the first heating．By comparison with the building blocks,the FTIR measurements indicated clearly the formation of strong hydrogen bonding between the carboxyl and pyridyl groups in the complex．The two broad bands at 1883.2 cm-1 and 2441.7 cm-1 were assigned to the stretching vibration of O-H group of the carboxylic acid in the hydrogen-bonded state of carboxyl-pyridyl units．The carbonyl peak of the carboxylic dimer at 1675.1 cm-1 shifted to 1682.9 cm-1 in the spectrum of the complex,and the two peaks 2543.5 cm-1 and 2659.5 cm-1 which were assigned to the Fermi resonance of the cathoxylic dimer disappeared．
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发布时间：2021-03-19 - 摘要：The effect of nano-CaCO3 with mean size of 30 nm and CPE on microstructure and properties of PVC blends was investigated．Nanoparticles of CaCO3 were prepared in a novel rotating packed bed reactor and modified by the selected surface modifiers．Then they were mixed with polyvinyl chloride,chlorinated polyethylene and the other reagents in high-speed stirrer and the mixtures were extruded by means of single-screw extrusion．The results showed that the CaCO3 nano particles toughen PVC／CPE blends significantly when the CPE content reached a certain value．The rigidity and the tensile strength of the blends were also increased．The notched impact strength of the PVC blend can reach 81.1 kJ／m2,which is 7.3 times higher than that of the blends without nano-CaCO3．The morphology of the fracture surfaces of blends was observed by SEM．The fracture microstructure of blends implied the mechanism that the toughness of PVC／CPE was remarkably improved by the addition of CaCO3 nano particles．And the microstructure of dispersed calcium carbonate nanoparticles in the matrix was observed by TEM．It was found that CaCO3 nanoparticles were well-dispersed in PVC matrix at nano-scale．It is confirmed that calcium carbonate nanoparticles after properly surface-treated can be used as a new functional material．When they are well-dispersed in PVC matrix,the PVC blend is toughened remarkably．The rheological property of PVC／CPE／nano-CaCO3 blends was also investigated．The final torque of PVC／CPE／nano-CaCO3 blend in Brabender tests was higher than that of the blend without CaCO3 nano particles．
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发布时间：2021-03-19 - 摘要：A new monomer,4-hexanoxyl-4′-undecylene-[10]-acyloxyazobenzene was synthesized using the main materials：phenol,underlenic acid,1-bromo-n-hexane,p-nitrophenol,thionyl chloride,by the substitution,reduction,couping and diazotization methods．A new polymer was prepared by hydrosilation reaction of poly (methylhy-drosiloxane) with the monomer．The chemical structure of the monomer and the polymer was confirmed by 1H-NMR and IR measurements and the full hydrosilation reaction of the polymer was confirmed．The liquid crystalline properties of the monomer and the polymer were investigated by using different scanning calorimetry (DSC) and polarized optical microscopy(POM),and their liquid crystallinity was evidenced．
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发布时间：2021-03-19 - 摘要：According to a new cluster theory for the concentration-dependence of polymer solution viscosity proposed recently,the concept‘ideal polymer mixture’was re-investigated and defined as one in which there does not exist any net attractive interaction between unlike polymers which could result in inter-chain association between unlike polymers．Based on the new definition,a new viscometric criterion for polymer-polymer miscibility was suggested．Namely,if the overall apparent association constant obtained experimentally (〈Km〉exp) of a mixture solution deviates positively from the weight-averaged value of the two components’ apparent association constants,the mixture could be judged as miscible．It was found that the new criterion agrees well with experimental data．
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发布时间：2021-03-19 - 摘要：The expanding behavior of vinylidene chloride(VDC)-acylonitrile(AN)-styrene(St) terpolymer particles containing 1-fluoro-1,1-dichloroethane(HCFC-141b) was monitored on line by a microscope equipped with a heating apparatus and an automatically photographing system．Effects of the factors such as copolymer composition,expanding temperature,concentration of blowing agent and particle size on the expanding behavior were investigated．It was found that an increase of AN or St units in VDC-AN-St terpolymer led to a decrease of expanding rate of particles．The expanding rate of VDC-AN-St copolymer particles increased with the increase of temperature and concentration of blowing agent,and decreased with the increase of the size of VDC terpolymer particles due to the loss of blowing agent to the surroundings. An “overshoot” phenomenon of particle growth was observed at high expanding rate,which may be attributed to the existence of inertia growth in free expansion of polymer particles．
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发布时间：2021-03-19 - 摘要：Carboxymethyl cellulose (CMC) is one of the most useful cellulose derivatives．However,it is difficult to obtain CMC with higher degree of substitution (DS),and CMC with lower DS often exhibits a poor solubility in water．In order to improve the degree of substitution of earboxymethyl cellulose,acrylic amide (AAm) was grafted onto cellulose,and the sodium carboxymethyl cellulose with AAm groups (AAm-CMC-Na) was synthesized．In the present work,a novel modified CMC hydrogel based on AAm-CMC-Na aqueous solution was obtained by using gamma irradiation under appropriate conditions．The swelling behavior,crosslinking kinetics of AAm-CMC-Na hydrogels and the effects of temperature,pH value and inorganic salt concentration on the swelling ratio of hydrogel were studied in detail．Experimental results showed that,when the concentration of AAm-CMC-Na aqueous solutions is above 12.5％,hydrogels could be prepared by gamma irradiation．However,comparing with radiation prepared CMC-Na hydrogels,the novel AAm-CMC-Na hydrogel could be produced at lower dose and lower concentration．Degradation is the predominant reaction in gamma irradiation for these two hydrogels．The swelling ratio of AAm-CMC-Na hydrogel in water was improved with the increase of temperature and had a maximum value in the range of pH=6～8,moreover,the swelling ratio decreased with the increasing of inorganic salt concentration and absorbed dose. The effect of CaCl2 solution on swelling behavior of AAm-CMC-Na hydrogel was more remarkable than that of NaCl solution．The irradiation prepared AAm-CMC-Na hydrogels showed good sensibility to temperature and pH value,which implied this novel hydrogel is expected to be a water absorption material and water preserver．
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发布时间：2021-03-19 - 摘要：The microbial polyesters have attracted attention as an biodegradable materials for a wide range of agricultural,marine and medical applications．It is important to investigate the biodegradation behavior and kinetics of the biodegradable reaction．Traditional Michaelis-Menten kinetics was originally derived for homogeneous reactions in which both the enzyme and the substrate are soluble．The enzymatic degradation of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is a heterogeneous reaction,because PHBV is an insoluble substrate,and the kinetic relation needs to be altered to fit it．In this paper,the kinetics of the enzymatic degradation behavior of PHBV was studied．It is well known that the enzymatic hydrolysis of water-insoluble film of PHB by depolymerases produces water-soluble products composed of monomers and dimers of R-3-hydroxybutyric acid．The rates of degradation were determined by the titrimetric methods,which are quantitative by directly measuring the acid groups formed as a result of ester bend hydrolysis．The degradation of PHA samples with different shapes and morphology was studied．The kinetic analysis revealed that the degradation reaction exponentials of PHBV powder,solution-casting film and solution-casting-leaching porous film were different,which were inconsistent with classical enzymatic kinetics．The variations of kinetics curves depended on the concentration of enzyme and PHA．A heterogeneous kinetics treatment was derived to describe the relationship of degradation rates with enzyme concentrations and substrates．The influence of PHBV physical morphology on their degradation was also investigated．The results show that the specific surface area and the shape of PHA samples effect the adsorption and combination of enzyme to substrates and finally conduce to the changes of enzymatic degradation process and the rate of degradation of PHBV．
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发布时间：2021-03-19 - 摘要：Polyethylene with broad molecular weight distribution can be obtained by using catalytic systems consisting of two or more catalyst components．An asymmetrically bridged metallocene compound [(CH3)2C(η-C5H4)(η-C9H6,)]ZrCl2 and different unbridged metallocene compounds(＼／Cp)2ZrCl2,(Cp)2ZrCl2 and (CP)2ZrCl2 were used to constitute three catalytic systems cocatalyzed with MAO for ethylene oolymerization．Polyethylene with short chain branch and broad molecular weight distribution was obtained．By changing the molar ratio of two-component metallocene catalysts and polymerization temperature,the activity of the ethylene polymerization and the molecular weight and molecular weight distribution of the resultant polyethylene were investigated．The molecular weight and molecular weight distribution of polyethylene were determined by viscometry and GPC．The melt point and crystailinity of polyethylene samples were determined by DSC．The results showed that the molar ratio and polymerization temperature had important effect on the activity and molecular weight．The results indicated that it was possible to tailor molecular weight and molecular weight distribution by changing the molar ratio of the two-component metallocene catalysts and polymerization temperature in ethylene polymerization with two-component metallocene catalyst systems．
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发布时间：2021-03-19 - 摘要：A soluble fluoropolymer poly(perfluoroctanoyloxyl-propyl methylacrylate) (PFPMA) was prepared using free radical polymerization．The structure and thormo-properties of PFPMA were characterized using FTIR,XRD,XPS,DSC and TG／DTA analyses．The surface properties of PFPMA films were determined by contact angle measurements and the surface free energy was calculated by using the data of contact angles．The results show that the surface free energy of the PFPMA film is as low as l4.2mN／m,and its contact angles are ll5。and 75。for water and hexadecane,respectively．
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发布时间：2021-03-19 - 摘要：Polymer electrolytes were prepared with hyperbranched polyurethane and linear polyurethane as the host polymer and LiClO4 as the ion source．FTIR spectra was used to analyze the bending degree of Li+ with carbonyl and ether groups．It Was found that Li+ preferred bonding with the ether group,and bonded with the carbonyl group when the salt concentration reached a certain level．The bending degree of Li+ with ether groups and the carbonyl groups both reached a saturated state at a salt concentration of EO／Li+=4．Raman spectra was applied to analyze the aggregation degree of anions ClO-4. The fraction of contact-ion pairs increased with increasing salt concentration．When the salt concentration increased to EO／Li+=4,the salt aggregates appeared,but the area fraction of aggregates was merely 1.2％．This indicated that the hyperbranched polyurethane could function as a” solvent” for the lithium salt．Conductivity analysis indicated that the conductivity kept increasing with increasing concentration of HPU and the conductivity maximum of the present system appeared at a higher salt concentration (EO／Li+=4) which could be attributed to the high solvating capability of the hyperbranehed polymer．The ionic conductivity of all samples was apparently enhanced with increasing temperature,and the Arrhenius phenomenological relationship could be used to describe the conductivity behavior.
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发布时间：2021-03-19 - 摘要：N-Isopropylacrylamide (NIPAAm) was introduced onto the surface of polypropylene (PP) films to form a layer of poly(N-isopropylacrylamide) (PNIPAAm) by UV-induced surface photograft polymerization reaction．Improvement on UV intensity and reaction temperature favored the increase of the grafting yield,yet it went through a maximum as monomer concentration was increased．Two photograft techniques,the xanthen-9-one pre-dipping method and dormant radical method,were tried and higher grafting yields were achieved by the latter．The existence of PNIPAAm grafted polymer layer was confirmed by FTIR,ESCA and SEM measurements．The acrylamide band Ⅰand Ⅱ in FTIR spectra of the grafted polymer shifted as the temperature changed,which revealed the temperature sensitivity of the grafted films．Moreover,a special sphere-like surface morphology of the NIPAAm layers due to the temperature-responsive behaviors was observed by SEM．
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发布时间：2021-03-19 - 摘要：A series of all-aromatic polyesters with high molecular weight derived from m-phthalic acid,4,4′-dihydroxybenzophenone,hydroquinone,and p-hydroxybenzoic acid were synthesized by direct polycondensation method in sulfonyl chloride (BsCI),dimethylforamide (DMF) and pyridine (Py) at various bisphenols ratios．The liquid crystalline behaviors and thermal properties of the all-aromatic polyesters have been characterized by polarized light microscopy (PLM),wide angle X-ray diffraction (WAXD),thermogravimetric analysis and differential scanning calorimetry (DSC)．The results show that the all-aromatic polyesters with high molecular weight can be synthesized in an easily controlled mild condition as compared with the usual ester exchange reaction．Under polarizing optical microscope,all the synthesized polyesters with different ratios of bisphenols show a very high degree of birefringence with threaded nematic texture in the molten state and strip texture after shearing from the melt．Comparing the polyesters with those synthesized by melt ester exchange reaction,the polyesters have a good crystallinity from the result of WAXD studies．All the polymers show high thermal stability and the decomposition temperature range for 5％ weight loss is from 427℃ to 476℃,hut there is no significant difference between their temperature of maximum decomposition．The results of DSC show that the glass transition can not be obtained in the first heating process,and can be observed in the cooling and second heating processes．In the first heating run,there exist two evident endothermal transitions in ca．200℃ and 270℃,and in the second run,only one in ca．270℃．The polyesters have excellent fiber-forming capability with a potential for melt spinning.
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发布时间：2021-03-19 - 摘要：The influence of supermolecular structures on the axial compressional behavior of poly(vinyl alcohol) (PVA) fibers was investigated．Two kinds of PVA fibers with different the morphological structure of molecular chains,PVA-H fiber and PVA-B fiber were studied．PVA-H fiber with a long-period structure that is made up of stacked folded-chain crystals has a homogeneous appearance,while PVA-B fiber with extended-chain crystals has a characteristic banded structure．The axial deformation behavior of PVA-B fibers was quite different from that of PVA-H fibers．When the PVA-B fibers were axially compressed,the PVA molecules in the banded structure were considerably kinked in zigzag fashion from band to band to form deep “crease”．Finally,all banded structures in the fiber were destroyed．It is suggested that (101)[010] slip plays an important role in the deformation of the PVA-B fibers.
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发布时间：2021-03-19 - 摘要：The micro-structure of silk fibroin and the structural difference between silk surface and bulk were studied using a range of analytical techniques,microscopy,Fourier transform infra-red spectroscopy in ATR mode,analysis of amino acids composition and FuLin reagent analysis；The compositions and distribution of the amino acids in silk fibroin,especially the main aromatic amino acids (tyrosine) which plays an important role on the structure and properties of silk fibroin was studied,in order to reveal the relationship between silk structure and the intrinsic defect of silk fabrics such as yellowing,easy-crease,and color fastness．The results show that there is multiple-layers structure in natural silk fibroin,with higher crystallinity in the in-layer than out-layer；The acids with large side-chain such as Lys,His,Cys,Arg,Asp,Phe,Leu,Glu,Tyr are richer in the outer-layer,and the amino acids with small side-chain such as Gly．Ala and Ser are richer in the inner-layer of silk fibrions．
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发布时间：2021-03-19 - 摘要：The interfacial tension on coarsening process of the polymer blend thin film on substrate was studied by using a phase contrast microscope and computer image analyzer．The ethylene vinyl acetate copolymers (EVAc) with different contents of VAc were blended with polyproplyene (PP),and a series of PP／EVAc blends with differene interfacial tension was obtained．It was found that the coarsening process of the polymer blend 2D thin film on glass substrate was always accelerated when the interfacial tension is larger than a threshold value to be about 0.48·10-5 N／cm．When the interfacial tension of the blends is less than the threshold value,the coarsening process of the polymer blend thin film on glass substrate is as same as the bulk of the blend；i．e．no occurrence the phenomenon of the substrate induced coarsening process is．This result corresponds to our previous research results．Using substrates with various surface tensions,the coarsening processes of the polymer blend was found to be similar．In other words,the accelerated coarsening processes exist in all cases．The particle coarsening process only depends on the interfacial tension of the blend and the existing of the substrate,does not depend on the character of the substrate.
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发布时间：2021-03-19 - 摘要：Chitosan (CS),an N-deacetylation product of chitin,consists of glucosamine and N-acetylglucosamine units linked through 1～4 glycosidic bends．CS rod is selected as a potential material for bone fracture internal fixation of human being due to its biodegradability and inherent wound healing．Incorporation of hydroxyapatite (HA),the mineral component of bone,could improve the bioactivity and the bone-bending ability．A HA filled CS rod was prepared by in-situ precipitation．The mechanical properties were characterized and evaluated for suitability as a bone graft substitute．X-Ray Diffraction (XRD) was performed to determine the change of the structure of HA in the before and after processing．Scanning electron microscopy (SEM) was carried out to investigate the microstructure of CS／HA composite．Effect of HA content on the mechanical properties and water absorption of CS／HA composite were also investigated．It was observed that the mechanical properties of the composite in the dry condition improved as the percentage of CS content increased．Mechanical properties of such CS／HA composite rod are much better than that prepared via traditional method．Bending strength,bending modulus,double shear strength and compress strength of CS／HA composite are 67.8 MPa,3.3 GPa,21.2 MPa and 47.8 MPa,respectively．All of these material properties are twice or three times stronger compared with that of nature bone of human being,indicating that such a novel bioabsorbable CS／HA composite could be used as internal fixation of bone fracture．Furthermore,the water absorption of CS／HA composite decreased when addition of HA powders into CS matrix,which contributes to postponing the attenuation of mechanical properties of CS／HA composite under moisture condition．
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发布时间：2021-03-19
Research Article
- 摘要：Ambient curable hydrophobic coatings received considerable attention during the past decade．In this study,a series of fluoropolymers with hydroxylic groups and an acid anhydride content polymer were synthesized by solution copolymerization under refluxing toluene．Their structures were characterized by FT-IR and DSC. In the presence of triethylamine,these two kinds of polymers were crosslinked with each other under ambient condition to form a coating with crosslinking degree up to 77％．With increasing the content of fluoromonomer in the feeding composition,the corresponding cured coating showed higher hardness and higher contact angle for water connected with other good properties in all instances．The contact angles were dependent to some extend on the structure of the fluoromonomers used and the hydrophobicity of the substrates．The present hydrophobic coating was further applied to copper surface．Compared with the uncoated one,the coated copper showed an improved performance for preventing the formation of frost on its surface.
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发布时间：2021-03-19 - 摘要：Carboxy containing colloidal particles were prepared from emulsion copolymerization of styrene-acrylic acid-butyl acrylate．The particle size and the size distribution were determined on mica by atomic force microscopy after evaporating the water of the diluted emulsion．A sandwich structure covalently attached between the layers and particles has been fabricated from nitro-substituted diazoresin (NDR) and carboxy containing colloidal particles by the self-assembly combining UV irradiation technique．The ionic bonds between the layers and particles convert to covalent bends under UV irradiation and the stable sandwich structure was achieved successfully．The assembly process,Ihe stability of the film toward DMF etching and the morphology of the films were also reported.
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发布时间：2021-03-19 - 摘要：A new biphenol-like monomer,4,4′-methylenebis [4-(1,4-phenylene)-phthalazin-1(2H)-one] was synthesized from phthalic anhydride and diphenylmethane in two steps．In the first step,Friedel-Crafts reaction was carried out in 1,2-dichloroethane between diphenylmethane and phthalic anhydride．The obtained product was used in the second step with hydrazine monohydrate added into its solution,followed by recrystallization in acetic acid．The melting point showed by differential scanning calorimetry of the bis(phthalazinone) monomer was 338.1℃．The overall yield of the biphenol-like monomer was 60％．A new polyphthalazinone was prepared from 4,4′-difluorodiphenylketone(DFK) and 4,4′-methylenebis [4-(1,4-phenylene)-phthalazin-1 (2H)-one] by solution polycondensation in N-methyl-2-pyrrolidone (NMP) with anhydrous K2CO3 as a catalyst．High molecular weight polymer was formed in 8 h at 190℃．The polymer was refined by precipitation from its 15％ NMP solution with methanol as the precipitating agent．The powder of the polymer was dried in a vacuum oven under l20℃ for 48 h and then under 200℃ for 4 h．The intrinsic viscosity of the polymer was 0.58 dL／g in NMP at 25℃．The polymer showed high glass transition temperature (Tg) at 258℃ by DSC．The decomposition temporature for 5％ weight loss (Td5) in nitrogen measured by thermogravimetric analysis occurred at 431℃．The solubility of the polymer was investigated at room temperature．The polymer was soluble in NMP,m-cresol and partially soluble in chloroform,and insoluble in N．N-dimethylacetamide (DMAc) and dimethyl sulfoxide (DMSO)．The methylene group and bis-(phthalazinone) structure in the backbone of the polymer contribute much to the good solubility,and the rigid structure of bis(phthalazinone) retains its good thermal properties．
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发布时间：2021-03-19 - 摘要：Poly(A-PTHF) can not be obtained from the conventional free radical polymerization,or atom transfer radical polymerization or reversible addition-fragmentation chain transfer polymerization of A-PTHF,due to low conversion and low degree of polymerization of poly (A-PTHF)．Thus,the homo-polymerization of A-PTHF macromonomer was performed under 60Co γ-irradiation with EPDTB(1-(ethoxycarbonyl)prop-1-yl dithiobenzoate) as initiator．After precipitated from methanol,pure poly(A-PTHF) was obtained．The block copolymerization of St was performed using Poly(A-PTHF) as the transfer agent and DCP(dicumy peroxide) as the initiator．Both of the homo-polymerization and the following copolymerization are controllable．The evidences are the linear relationship between In([M]0／[M]) and polymerization time,the linear evolution of Mn with conversion and the narrower polydispersities．The molecular structures of the poly(A-PTHF) and the block copolymer PSt-b-P(A-PTHF) were characterized by 1H-NMR as well as gel permeation chromatography(GPC)．The polymerization mechanism of the homo-polymerization of(A-PTHF) and the copolymerization of poly(A-PTHF)with St were discussed respectively．
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发布时间：2021-03-19 - 摘要：Monodisperse core-shell (polystyrene/DAAM-EA-AM) emulsions were prepared by two-step seed polymerization,and crosslinked films were obtained by ambient drying the copolymerization emulsions accompanying a interfacial crosslinking between DAAM／ADDH．The crosslinking degree increased with thermal treatment temperature and time. After alkaline hydrolysis of ester and amide groups resulting carboxylic groups,the films were transformed to be mesostructured hydrogels．The chemical composition and ordered morphologies were experimentally confirmed by FT-IR,SEM and POM．Water uptake of the hydrogels decreased with the thermal treatment time of the films,implying the crosslinking degree also increased．
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发布时间：2021-03-19
Research Bulletin
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