最新刊期
卷 ， 期 4 ， 2004
- 摘要：The crystallization kinetics has been investigated by differential scanning calorimetry for polyamide 1218,a novel even-even nylon with long allkyl segments．Avrami equation and Ozawa approach have been adopted to study both the isothermal and non-isothermal processes．It is shown that the Avrami equation is applicable for isothermal crystallization very well,and the calculated Avrami index n is 3,which demonstrates that the crystallization of nylon 1218 is growing with global tridimensional crystals in this situation. As for the non-iosthermal crystallization,the Ozawa methed only fits at fast cooling rates,and the calculated Ozawa index m is 4,which indicates nylon 1218,in non-isothermal terms,may crytallize by a way of homogeneous nucleation and tridimensional growth. In addition,the activation energies for isothermal and non-isothermal crystallization have been determined according to the Arrhenius and Kissenger methods,respectively. A comparison of the activation energy values of nylon 1218 with those of nylon 1012 and nylon 11 indicates that at same conditions an increase of the alkyl segment length in the nylon molecules is beneficial to their crystallization,and the even-even nylons with long alkyl segments are easier to crystallize than the single nylons.
- 2
- |
- 11
- |
- 14
发布时间：2021-03-19 - 摘要：Studies on the adsorption thermodynamics and kinetics of 2-thiopheneacetic acid by XAD-4,NDA-100 and ND-90 resins were carried out through static experiments. The results showed that the adsorption of 2-thiopheneacetic acid on XAD-4 resin was a Langmuir monolayer type one,and the adsorption rate implied a first order kinetics. The adsorption data of 2-thiopheneacetic acid on NDA-100 and ND-90 resins were also discribed well by the Langmuir isotherm,which was caused by the capillary condensation and the volume filling of micropores besides the monolayer adsorption．The adsorption of 2-thiopheneacetic acid on NDA-100 and ND-90 resins is carried out in two regions the macropore／mesopore region and the micropore one．The adsorption rates in the two regions both fulfill the first order kinetics.
- 2
- |
- 8
- |
- 17
发布时间：2021-03-19 - 摘要：The tensile behavior,noteched Izod impact strength and the morphology of the impact fracture surfaces of ternary PS blends(PS／SBS／CaCO3) were investigated. Two kinds of CaCO3 fillers with micrometer and nanometer sizes were used．Its was found that the CaCO3 of micrometer sizes was a better toughness modifier than that of nanometer sizes,while the latter gave more improvement in the stiffness of the system．The toughness of the PS blends increases apparently with the increase of the SBS／CaCO3 content．A brittle-ductile transition was observed with increasing the SBS／CaCO3 content. All the results including the impact and tensile tests and morphological observations indicated the transition in the same content region of 31.0 wt％～37.5 wt％.
- 35
- |
- 10
- |
- 7
发布时间：2021-03-19 - 摘要：The main disadvantages of the conventional thermoplastic starch (TPS) are the retrogradation,poor water resistance and unsatisfactory mechanical properties particularly under wet or dry environments．In this paper,formamide and urea were used as a mixed plasticizer to prepare urea／formamide-plasticized TPS(UFPTPS) with both the good mechanical properties and the good retrogradation resistance. FTIR analysis indicated that the micro-environments of the chemical groups in formamide-plasticized TPS(FPTPS) changed less than in glycerolplasticized TPS(GPTPS) during a period of 70 days. This was related to the fomation of more stable hydrogen bonds between formamide and starch. By Scanning Electron Microscope(SEM) the native cornstarch granules were proved to transfer to a continuous phase with the destruction of all crystallinity．The effect of water contents on the mechanical properties of UFPTPS was also studied,and UFPTPS had good ductility at water contents of 9％～34％．After being stored for one week at RH=33％,the tensile strength,elongation and energy at break of this TPS reached 4.83 MPa,104.6％ and 2.17 N·m,respectively. The influence of formamide and urea on the retrogradation of TPS was studied using X-ray diffractometry. It was found that the mixture of formamide and urea could effectively restrain the retrogradation and prevent urea from crystallization. On the other hand,both the thermal stability and water resistance of UFPTPS was better than those of TPS plasticized by each single plasticizer (including glycerol)．The TPS properties mentioned in this paper were ameliorated by the mixture of formamide and urea(10％／20％ weight based on starch),mainly for it could form more strong and stable hydrogen bonds with starch hydroxy groups than glycerol could. As a novel plasticizer,the mixture of formamide and urea would be potential in extending the application scopes of TPS.
- 2
- |
- 8
- |
- 19
发布时间：2021-03-19 - 摘要：Dynamical vulcanization process was successfully applied to the PP／epoxy blends．The compatibility of two components,dynamical cure of the epoxy resin and mechanical properties of the blends were studied．Since the epoxy resin and PP are immiscible,maleic anhydride-grafted polypropylene (PP-g-MAH) was used as a compatibilizer．The dynamically cured PP／epoxy blends with the structure of epoxy resin particles finely dispersed in the PP matrix were obtalned．The tensile strength and flexural modulus of the dynamically cured PP／epoxy blend containing 5％ epoxy resin increase by 30％ and 50％,the impact strength increases by 15％ compared to PP,but the elongation at break decreases dramatically．With further increasing the epoxy resin content,the flexural modulus and tensile strength increase slowly and the impact strength varies slightly,while the elongation at break decreases rapidly．Dynamic mechanical thermal analysis (DMTA) shows that the dynamically cured PP／epexy blends have higher storage modulus (E′) compared to PP．
- 14
- |
- 12
- |
- 3
发布时间：2021-03-19 - 摘要：A polystyrene (PSt)／nano-SiO2 nanocomposite was prepared through emulsion polymerization of styrene in the presence of SiO2,and the mechanism and process of the redispersion of the aggregated nano-SiO2 particles during emulsion polymerization were studied．It was found that the commercial nano-SiO2 particles were usually in the state of aggregation according to TEM and SEM results,and their diameter was over the range of nanometer. With the increase of the polymerization time,the conversion of styrene gradually increased and the latex diameter of the PSt／SiO2 microcapsule decreased．When the polymerization time reached 120 min,the conversion and the latex diameter tended to be constant．The TEM photograph also showed that the PSt／SiO2 microcapsule had the sea-island structure and the size of SiO2 particles was in the range of nanometer,which suggested that the aggregated nano-SiO2 particles were gradually redispersed during emulsion polymerization．FTIR studies approved that in addition to the formation of homopolymer the grafted polystyrene had also been produced on the SiO2 surface,which improved the interfacial compatibility between polystyrene and nano-SiO2．The released heat during the polymerization and the shear force were the main reasons causing the redispersion of the aggregated nano-SiO2．
- 4
- |
- 10
- |
- 7
发布时间：2021-03-19 - 摘要：Ultra-fine polyhydroxybutyrate-valerate(PHBV) fibers were prepared via electrospinning technique. The structure and morphology of the electrospun fibers were determined by scanning electron microscope(SEM),thermal analysis(DSC),wide angle X-ray diffraction (WAXD) and FT-IR．The effects of concentration,electrical potential and the distance between the spinning tip and the collector upon the morphology of electrospun fibers were also discussed．The results show that electrospinning occurs only when electrical potential exceed a critical value which is related with solution properties．When solution concentration in creases,the average diameter of electrospun fibers increases．And the increase of electrical potential may result in decline in average diameter. With the increase in distance between the tip and the collector,the diameter also experiences a slight growth．It is also found that electrospinning process promotes the crystallation of PHBV,which may be caused by the orientation of molecule chains due to electrical force stretching.
- 2
- |
- 8
- |
- 16
发布时间：2021-03-19 - 摘要：Bisoxazolines have been recently applied as chemical chain extenders of some polymers．The reaction behaviors of bisoxazolines,as adding-type chain extenders,have been studied to evaluate their coupling effects as the chain extenders for polyaimde1010 (PA1010)．2,2′-bis-(2-oxazoline) (BOZ) and 1,4-bis-(4,5-dihydro-2-oxazolyl)benzene (PBO) were tested,the former of which gave the better results．It had been shown that the torque of PA1010 melt increased dramatically with reaction time after the addition of chain extender．However,a slow decrease of torque could be found in the later stage of the chain extension reaction,probably due to degradation of chain-extended products at high temperature. There existed an optimal dosage of the chain extender,lack of which caused deficiency of chain extension and excess of which led to more blocking reaction．The end carboxyl group concentration of polyamide1010 decreased dramatically after chain extension．The effect of temperature on the chain extension reaction rate accorded with the Arrhenius exponential formula．The intrinsic viscosity of chain-extended products was much higher than that of the virgin PA,indicating that the molecular weight had been obviously enhanced.
- 3
- |
- 10
- |
- 9
发布时间：2021-03-19 - 摘要：The kinetic model of chain extension reaction between bisoxazoline and carboxyl group was founded and modified to fit the real experimental results. By the Runge-Kutta numerical method,not only has the change of reaction conversion with time been clearly revealed,but also the key factors that mainly influence the chain extension have been easily tested．The ideal linear model of chain extension accords to a large extent with the former period of the reaction. However,it cannot illustrate the “degradation” in the latter period due to the thermal unstability of products．Modified linear model gives more congruent results．During the whole period of the reaction,the reaction rate constant k and ratio of both reactants r are the key factors. The changes of reaction conditions,such as temperature and chain extender dosage,are simulated easily by varying the value of k and r．Considering the diffusibility in the polymer melt with high viscosity,the distinction of coupling effect of BOZ and PBO can be explained．No other than the same reason,the analysis could only be kept in the qualitative stage at present．
- 4
- |
- 10
- |
- 4
发布时间：2021-03-19 - 摘要：A new side chain liquid crystalline polymer based on the backbone of polymethacrylate containing triphenyl which was connected with ester bond as side chain mesogenic moiety,and its flexible spacer was two methylenes was prepared．FT-IR,1H-NMR,POM with hot stage,DSC and WAXD were used to study the structure,phase behavior and mesophase texture of this polymer and monomer．The monomer shows nematic and semectic phases and the polymer is nematic over a wide temperature range. The solidification-induced band texture can be observted in nematic phase of the side chain liquid crystalline polymer．
- 4
- |
- 8
- |
- 2
发布时间：2021-03-19 - 摘要：It has been reported that flexible polymers,such as polybutadiene (PB),can be introduced as fillers into oil absorbing resins to improve the tight network structure,low oil absorption ratio and irreversible oil-releasing properties of these resins which are prepared usually only by chemical crosslinking．However,the double-bond of PB can react with the monomers to introduce additional chemical crosslinks．In order to compare the synthesis and properties of high oil absorption resins filled with various materials,paraffin,is used as a filler without any double-bond in the suspension copolymerization of dodecyl methacrylate,styrene and ethylene glycol dimethacrylate initiated by benzoyl peroxide．The effects of monomer recipe,concentration of fillers and chemical crosslinks on the oil absorption capacity and gel fraction of copolymers obtained are studied．It is found that the high oil absorption resin filled with PB has physical crosslinks,while the resin filled with paraffin has none．The oil absorption capacity as well as the gel fraction of the former increase with the increasing of PB amount,and its controlled release properties are also affected．Meanwhile,the oil absorption capacity of the latter also increase,but its gel fraction does not change with the increasing of paraffin content．
- 4
- |
- 8
- |
- 5
发布时间：2021-03-19 - 摘要：A novel soluble π-conjugated polymer,poly [(3-acetyl) pyrrole-2,5-diyl(p-nitrobenzylidene)] (PAPNBE) is synthesized by condensation of 3-acetylpyrrole with p-nitrobenzaldehyde．The chemical structure and properties of the intermediates,the precursor,poly[(3-acetyl)pyrrole-2,5-diyl(p-nitrobenzylidane)] (PAPNBA),and PAPNBE are characterized by 1H-NMR,FT-IR and UV-Vis spectroscopy．The results show that the pyrrole rings in PAPNBA and PAPNBE mainly exist in the aromatic state and the quinonoid state,respectively．The solubility of PAPNBE in dimethyl sulphoxide (DMSO),dimethyl fomamide (DMF) and N-methyl pyrrolidone (NMP) is 0.13～0.15 g／mL,0.34～0.37 g／mL and 0.41～0.45 g／mL,respectively．The result shows that PAPNBE can be easily solved in polar solvents．The conductivity of PAPNBE doped with concentrated sulfuric acid is 2.7×10-6 S/cm．The energy bandgap of PAPNBE is about 1.78～1.94 eV．
- 3
- |
- 8
- |
- 3
发布时间：2021-03-19 - 摘要：The effects of maleic anhydride grafted thermoplastic elastomer (TPEg) as a compatilizer on the compatibility,morphology and performance of polypropylene／polyamide6 blends were studied．The results showed that TPEg greatly improved the compatibility of the blends. With an increase in TPEg content in the blend,the size of minor component domains decreased greatly and the notched Izod impact strength and elongation at break of the final blends improved obviously. The non-isothermal crystallization behaviors of PP and PA6 in the blends were different from those in their pure polymers. The crystallization temperature of PP was promoted by the PA6 component due to its nucleating effect. While a fractionated crystallization was detected for PA6 when TPEg was used,the first crystallization occurred at a temperature slightly lower than the Tc of pure PA6,and was reduced with increasing TPEg content in the blends；the second crystallization happened coincidently with the crystallization of PP．The strong interactions between PP or PA6 and TPEg at the interface increased the Tg of the both the PP and PA6 domains in the blends,Based on these observations,a microstructure schematic model was proposed for the PP／PA6／TPEg and PP/PA6/TPE blends.
- 7
- |
- 11
- |
- 13
发布时间：2021-03-19 - 摘要：The polymerization of MMA and EMA by using a catalyst of Fe(acac)3-Al(i-Bu)3-8-hydroxy quinoline was investigated．The structure of the polymers is characterized by using NMR and IR techniques. The polymers obtained have mainly isotactic and syndiotactic structures．Molecular weight and its distribution were studied by GPC. The polymerization can be realized in solvents such as aromatic hydrocarbon and alkane. The yield is higher in alkane then in the others. The suitable Fe／8-hydroxy quinoline molar ratio is unity．The suitable Al／Fe molar ratio is eight. The suitable concentration of catalysts is [Fe] =8.0×10-3～ 1.2×10-2 mol／L．The increasing reaction temperature causes an increase of the polymer yield．The suggested temperature range is 70～90℃. Kinetic studies show that the MMA and EMA polymerization are reactions of first order with respect to the monomer concentration. The apparent activation energies of MMA and EMA polymerization are 36.3 kJ／mol and 46.4 kJ／mol,respectively.
- 2
- |
- 8
- |
- 2
发布时间：2021-03-19 - 摘要：A novel method was developed to polymerize acrylamide in an opaque inverse emulsion system by UV light initiation,which was usually used in a transparent system or semi-transparent system,such as solution systems and micro-emulsion systems．Using 2,2-Dimethoxy-2-phenylacetophenone (DMPA) as an initiator,Span80+OP10 as a blend emulsifier,the inverse emulsion polymerization of acrylamide in kerosene could be completed in about 20 min with exposure under a medium pressure mercury lamp and proper mixing,and the molecular weight of the produced polymer was as high as 107. No constant polymerization rate period was observed throughout the whole polymerization process,and there was no dramatic difference between the size of the initial monomer droplets and the size of the final inverse latexes according to scanning electron microscope observation,indicating that the polymerization was nucleated inside the monomer droplets．The influences of the type and concentration of photoinitiator,monomer concentration,emulsifier percentage and reaction temperature on polymerization were investigated．The initiating activity of photoinitiators is in an order of Irgacure 2959 ＞ (ITX+EDAB) ＞ BDK．When the concentration of photoinitiator increases,the reaction rate increases at first,then begins to decrease after the reaction rate reaches a maximum value．Both the reaction rate and the molecular weight increase when the monomer concentration increases．With the increase of the emulsifier percent age the reaction rate increases,while no dramatic change displays in the molecular weight．The overall activation energy of polymerization was measured as 13.34 kJ／mol.
- 34
- |
- 8
- |
- 10
发布时间：2021-03-19 - 摘要：Ring-opening copolymerization of phthalic anhydride (PA) with propylene oxide (PO) was successfully carried out by using double-metal cyanide (DMC). The characteristics of the copolymerization were presented and discussed．The structure of the copolymer was characterized with IR and 1H-NMR. The number-average molecular weight (Mn) and molecular weight distribution of the copolymer were measured by GPC. The results showed that DMC was a highly active catalyst for the copolymerization of PA and PO,giving high yield with a rate much higher than that of PO homopolymerization with the same catalyst at a low catalyst level of 60 mg／kg．This copolymerization can be also carried out in many organic solvents,and it was easier to be carried out in polar solvents such as THF and acetone than in non-polar solvents such as ether and cyclohexane．The proper temperature for reactions carried out in solutions was in the range of 90 ～ 100℃. That was lower than the temperature range for bulk-copolymerization．The Mn was affected by the catalyst level,reaction temperature and trace water．Mn was in a range of 2500～4000 under firm polymerization conditions by removing trace water and other impurities．The kinetics of the copolymerization was also studied．The results indicated a first order relationship between the copolymerization rate and the monomer concentration.
- 40
- |
- 10
- |
- 3
发布时间：2021-03-19 - 摘要：The blend membranes of silk fibroin (SF) and hydroxypropyl methylcellulose (HPMC) were made．The effect of HPMC on the conformation transition of silk fibroin membranes was analyzed by Fourier transform infrared spectrum,X-ray diffraction,and Differential scanning calorimetry．The results demonstrated that the content of blending HPMC had a great influence on the conformation of silk fibroin membranes．The conformational change from a random coil or Silk I to β-sheet structure occurred when blending 3％～10％ HPMC and the β-sheet content was maximal when HPMC content was 7％．This result is due to the formation of intermolecular hydrogen bonds when some content HPMC was mixed with fibroin．The result of water-solubility showed the blend film was almost insoluble when HPMC content was 7％.
- 4
- |
- 9
- |
- 0
发布时间：2021-03-19 - 摘要：Waterborne epoxy resin／silica sol hybrid dispersions were prepared by in-situ dispersion of graft epoxy resin with both the silica sol and water simultaneously. The hybrid interaction between the graft epoxy resin and the silica sol with different particle sizes was observed through the measurements of FT-IR spectra and ζ potential．Compared with the graft epoxy resin water dispersion,the hybrid dispersions exhibited lower viscosity and smaller particle size. In this case,a mechanism of forming the hybrid water dispersion was proposed and discussed．Some surface properties of films prepared from these hybrid water dispersions were measured．The higher hardness and better water resistance for such surfaces of films were observed,resulting from the enrichment of silica sols on the surfaces of the hybrid films．
- 3
- |
- 9
- |
- 9
发布时间：2021-03-19 - 摘要：A new kind of functional cellulose fibre grafted β-cyclodextrin (β-CD) with epichlorohydrin was synthesized in alkaline solution．The fibre not only kept the original characterization of β-CD to form inclusion complexes,but also contained more hydroxyl group(—OH) with could coordinate to inorganic heavy metal ions. The effects of factors such as temperature,concentration of solution,pH value,etc. on the enrichment properties were investigated. The results showed that the process of isothermal enrichment fits the Langmuir equation．The enrichment velocity is controlled by liquid film diffusion．The enrichment capabilitie of the fibre for inorganic heavy metal ions (Pb2+,Cu2+,Cd2+) were investigated and the enrichment contents of fiber for the above-mentioned metal ions were 0.25,0.30 and 0.34 mmol／g,respectively,the enrichment mole ratio：nCu2+／nβ-CD=2.9:1,nPb2+／nβ-CD=3.9:1,nCd2+／nβ-CD=4.3:1．
- 40
- |
- 10
- |
- 8
发布时间：2021-03-19 - 摘要：Temperature sensitive polymers,poly-N-isopropyl acrylamides (PNIPAAm) with different molecular weights,were prepared by radical polymerization．The molecular weight distribution and lower critical solution temperature of these polymers were deter mined by GPC and spectrophotometry．The feasibility of the polymer in assisting the refolding of denatured lysozyme was examined,by directly diluting the denatured lysozyme into refolding buffer containing PNIPAAm of different molecular weight．PNIPAAm with the mean molecular weight of 22,000 (M_ PNIPAAm) showed the best function of assisting lysozyme refolding,as indicated by the recovery of lysozyme activity from the denatured lysozyme sample．The molecular interaction of PNIPAAm with lysozyme and its implication on the structure change of lysozyme were investigated by fluorescence emission spectroscopy．The effects of lysozyme concentration and temperature on the lysozyme refolding were examined and the synergy of urea and M_ PNIPAAm on lysozyme refolding was identified．The suitable temperature for lysozyme refolding was chosen according to the temperature responsive behavior of PNIPAAm. The results shown by present study showed the high potential of temperature sensitive polymers in high concentration protein refolding in vitro in large scale．
- 38
- |
- 10
- |
- 7
发布时间：2021-03-19 - 摘要：The control of particle size and its distribution has become more and more important both in theory and in practice in emulsion polymerization field．In this study,emulsion polymerization of methyl methacrylate (MMA),ethyl acrylate (EA) and acrylic acid (AA) was carried out in the absence of emulsifier,and the influences of ingredients and conditions on polymerization,latex particle size and its distribution were investigated,and latex particles with narrow size distribution as well as with carboxyl groups on their surface were synthesized．The results showed that the high monomer conversion and narrow latex particle size distribution were obtained when large amount of initiator (APS) was introduced into the polymerization system at the beginning in three-step addition process. With the increase of APS and AA,the particle size decreased and the monomer conversion increased,and a similar result was also observed with the temperature increase．It was found that NH4HCO3 is a key material for the control of particle diameter (Dp). Dp increased with the increase of amount of NH4HCO3,and the Dp of monodispersed P(MMA-EA-AA) latex particles can be well controlled in the range from 300 to 600 nm by adjusting the amount of NH4HCO3 used．Moreover,latexes with high monomer conversion and narrow particle size distribution can be obtained when a moderate stirring rate of 300 r／min was selected．
- 39
- |
- 10
- |
- 9
发布时间：2021-03-19 - 摘要：Three Semi-interpenetrating polymer networks (Semi-IPNs) composed of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA),and poly (ethylene oxide),PEO,were synthesized by γ-radiation technology. The optimum synthesizing conditions have been found in the work．The equilibrium swelling ratio,EDS,of the Semi-IPNs was effected by the weight ratio between PEO and DMAEMA. When there was a little PEO (～3 wt％) in the Semi-IPNs,the EDS of Semi-IPNs was much larger than that of PDMAEMA,as the weight ratio of PEO in Semi-IPNs increased the EDS of Semi-IPNs decreased gradually and tended to be stable．The Semi-IPNs showed obvious electric-responsiveness,and the effect was dependent on the weight ratio of PEO in the Semi-IPNs．The electric-responsiveness was the most remarkable when the weight ratio of PEO was 5％ in Semi-IPNs. The Semi-IPNs were used successfully in entraping and electric field controled release of a Chinese traditional medicine,saponins．
- 32
- |
- 8
- |
- 3
发布时间：2021-03-19 - 摘要：Conjugated copolymers were obtained by the polymerization of 2,5-bis(4-bromo-benzene)-1,3,4-oxadiazole (M-Ⅰ) and 1,4-divinyl-2,5-dibutoxybenzene (M- Ⅱ) through Pd-catalyzed Heck reaction．Bothmonomers and polymer were characterized by NMR,MS,FT-IR,UV,fluorescent spectroscopy,GPC,elemental analysis and thermal analysis. The 1,3,4-oxadiazole unit is a chromophore,having good hole-transporting property and oxygen and heat stability. The polymer can emit very strong green fluorescence．It is expected to be used as polymer materials with electro-optical properties．
- 9
- |
- 10
- |
- 10
发布时间：2021-03-19 - 摘要：A series of crosslinkers(polyethylene glycol diacrylate,PEGDA) with different molecular weights were synthesized through end-capping of PEG by acryloyl chloride．The structures of the PEGDAs were characterized by FTIR．The water-absorbency of sodium polyacrylate crosslinked with PEGDAs was determined. In the experiments of water-swelling in deionized water,it was revealed that when the molecular weight of the crosslinker increased,the maximum of equilibrium water-absorbability of the synthesized superabsorbents was enhanced and the rate of water-swelling increased too,but the relative rate of water-swelling decreased．The relationship between the network structure of the superabsorbents and the water-absorbency was also discussed．Comparing PEGDA and MBA,the superabsorbents crosslinked with the former had much stronger water-absorbability,fewer residual monomers and less dissoluble linear polymers than the one crosslinked with the latter．
- 33
- |
- 8
- |
- 7
发布时间：2021-03-19 - 摘要：A Series of photo-sensitive macromonomers FAnC(n=1～4) were synthesized by using caprolactone-modified acrylates,FAn and cinnamyl choride,and copolymers PMFAnC were synthesized by free radical copolymerization of FAnC with MAA in DMF using 2,2′-azobisisobutyronitrile as initiator．The structures of copolymers were characterized by using GPC,DSC,IR and 1H-MNR techniques．The copolymers form spherical micelles in aqueous solutions with PFAnC chains as the core,and PMAA chains as the corona．The stable nanospheres were prepared by photo-crosslinking of the cores of the micelles．These micelles were characterized by DLS and TEM．The results showed that PMFAnC could self-assemble into nanometer micelles with narrow size distribution,and the hydrodynamic radius Rh of the crosslinked micelles was smaller than that of the uncrosslinked ones．The critical aggregation concentratio of micelle formation and the Rh value both decreased with increase of the n value of the copolymers．
- 3
- |
- 8
- |
- 8
发布时间：2021-03-19 - 摘要：In aqueous solutions,orderly polyelectrolyte-surfactant complex precipitates can been formed through electrostatic interaction．During complexing process,the conductivity of polyelectrolyte aqueous solution increases with adding of surfactant because of release of small inorganic electrolyte ions which have high conductivity. When polyelectrolyte and surfactant react according to equivalence and their concentrations are lower,the conductivity is distinctly turned．So the conductometric titration method can be used for measuring the composition of water-soluble copolymer containing ion monomer through complex reaction between polyelectrolyte and surfactant．In this investigation,the composition of copolymer P(AM-co-NaAMPS) of acrylamide (AM) and 2-acrylamido-2-methyl-propanesulfonate sodium (NaAMPS) has been determined with the aqueous solution of cetyl trimethyl ammonium bromide (CTAB) as titrant at a concentration of 0.001 mol·L-1 by conductometric titration method．The results obtained were compared with the results of element analysis,and were very satisfactory．It can be expected that the contents of ionic groups in water-soluble macromolecules can all be measured by using above complex reaction conductometric titration method．
- 3
- |
- 10
- |
- 8
发布时间：2021-03-19
Research Article
- 摘要：Molecularly imprinted polymers (MIPs) were prepared by using acrylic derivatives as the functional monomers,ethylene glycol dimethacrylate (EDMA) as the cross-linker,bovine serum albumin (BSA) as the template．In order to obtain qualified protein imprinted polymers,detailed studies were carried out over the polymer compositions,chemical reagent adding sequence,UV radiation time and synthetic conditions．The experimental data showed that the BSA imprinted polymers,compared to their blank counterpart,exhibited desired adsorption affinities and selectivity to the BSA molecule,and the amounts of adsorption were obviously higher than that of the blank polymer．
- 2
- |
- 11
- |
- 2
发布时间：2021-03-19 - 摘要：There has been much interest in polymerization catalyzed by enzymes (“enzymatic polymerization”) as a new methodology of polymer syntheses．Recently,enzymatic synthesis of polyaromatics has been developed. Peroxidase-catalyzed polymerization of phenol and its various derivatives proceeded to give polymers with a complicated structure,which is hard to synthesize by conventional oxidative polymerizations．As a p-diphenol oxidase,laccase could be used to catalyze the oxidative reaction and macromolecule synthesis．The polymerization of 4-phenylphenol was carried out in the mixture of buffer (pH 4) and organic (15:85,vol％) catalyzed by a laccase,produced from white rot fungus,at 35℃ for 48 h to form a polymer,2,6-poly (4-phenylphenol) with molecular weight above 80,000,which was determined by GPC．The polymer was analyzed by DSC to show that the glass transition temperature is 168.84℃ and the decomposition of this polymer took place at 301℃．The structure of this polymer is characterized by IR,H-NMR and 13C-NMR spectra．It’s reasonable to conclude that polyphenol with phenol hydroxy groups on the molecular chains are formed through laccase enzymatic polymerization．
- 13
- |
- 9
- |
- 9
发布时间：2021-03-19 - 摘要：With interfering illumination of Ar+ laser beams (488 nm),surface relief gratings (SRGs) were photo-inscribed on epoxy-based azo polymer (BP-AZ-CN) films．The modulation depth was about 160 nm and the spatial period was about 670 nm．The quartz slides covered with SRG films were assembled to liquid crystal (LC) cell to study the LC alignment behavior．Homogeneous liquid crystal alignment was observed in the surface relief gratings regions of the LC cell. Alignment of LC molecules was monitored by measuring the transmittance passing through the cell between crossed polarizers as a function of the angle of the cell rotating around the experiment optical axis．The transmittance changed periodically with a regular 90。separation of the rotational angle and the pretilt angle of the cell Was found to be 3.2。．This alignment technique could have useful applications in the future LC displays.
- 2
- |
- 9
- |
- 2
发布时间：2021-03-19 - 摘要：It is reported report herein the synthesis and characterization of a new mesogen-jacketed polymer containing an electron deficient oxadiazole unit——poly{2,5-bis[(5-tert-butylphenyl)-1,3,4-oxadiazole] styrene}(BBPOS)．BBPOS can be dissolved in THE,CHCl3,xylene,and DMSO．The structure of the monomer and the polymer was confirmed by elemental analysis,NMR,MS and GPC．The optical and electronic properties of the polymer were investigated by UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The results show that the polymer films emit greenish-blue light (λmax=390 nm) upon UV excitation．Thermo-analysis showed that the glass-transition temperature of the polymer is at 117℃．Moreover,its weight loss was less than 5％ on heating to about 349℃ under nitrogen atmosphere．
- 4
- |
- 10
- |
- 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