最新刊期
卷 ， 期 3 ， 1995
- 摘要：he results of compatibilization in blends of similarly-charged ionomers are presented.The blends of SVp/BmaVp (Poly(styrene-co-4-vinyl pyridine))with Vp as a minor component were treated with a series of metal acetates and carboxylic acids, respectively. Based on the coordinated complexation between pyridine rings and the ions and proton-transfer from the the carboxylic acid to pyridine rings. both SVp and BmaVp are charged with positive ions.DSC results show an apparent compatiblization effect of the blends by introducing the ions into the polymer chains,and the level of the effect depends on the nature and amount of the metal ions and the acids.
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发布时间：2021-03-19 - 摘要：WAXD and SAXS were used to study the morphology structure of a new type polyether-polyester-polyurea cast elastomer.The WAXD result shows that the crystallinity in its hard segments is in the order of HDI M MDI M TDI by using three different diisocyanates.As for the mixd synthesis series of HDI and MDI,three phases morphology are formed due to the quite different reaction rates with "polamine".The SAXS result shows that the increasment of "polamine" molecular weight is favourable for the phase separation of soft and hard segments. For dif-ferent diisocyanates, the degree of phase separation is also in the order of HDI>MDI>TDI.
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发布时间：2021-03-19 - 摘要：The polyesteramide (PEA) is synthesized by two methods.One of them is two-step method,firstly BAET and BHET are synthesized from the reactions of DMT (dimethyl therephthalate) with EA (ethanolamine) and TPA(terephthalic acid) with EG (ethylene glycol),reapectively;then BAET and BHET are condensation copolymerized.The chemical structure of the BAET is characterized by IR,IH--NMR and GC--MS.Another is one--step method that is synthesized by copolycondensation of DMT,EG and EA directly.All of the copolymers are characterized by the determination of nitrogen content, IR and NMR, The cha\emical reactions procssaes are discussed.
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发布时间：2021-03-19 - 摘要：series of polyalkylenebenzimidazole were synthesized by solution polycondensation and polymeric membranes were cast from formic acid solution at low pressure and room temperature. The relationship between gas permselectivity and chemical structure of polyalkylenebenzimidazole was discussed.It was found that the permeability order of hydrogen;carbon dioxide;oxygen;nitrogen;and methane is fit for ordinary glass polymers.The polymers that have longer flexible polymeric chain have higher gas permeability,but lower selectivity than the polymer that have shorter flexible chain. Gas permeability rises and selectivity reduces if temperature of transport gas increases. It reveals that the gas permeability will rise,if flexible segment is introduced in to rigid backbone for some aromatic polymers.
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发布时间：2021-03-19 - 摘要：The mechanism of crystallization and liquid crystallization of an aromatic thermotropic polymer-thermotropic poly (octamethylene p, p'-bibenzoate) were investigated detailedly with DSC and hot-polarized microscope and the surface fre energy and temperature coefficient of these phase transitions were determined and estimated. The results suggest that liquid crystallization process of the polymer is heterogeneous in two-dimentional nucleation and linear growth in twodimensional with a value of Avrami exponent n to be 2.7, while the crystallization process is heterogeneous in two-dimentional nucleation and linear growth in three-dime-nsional with a value of n to be 4.2-4.5. From the analysis of surface free energy and temperature coefficient of liquid crystallization and crystallization processes,it is found that liquid crystallization process is much faster than the crystallization process, and the liquid crystallization is more temperature sensitive than the crystal-lization.
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发布时间：2021-03-19 - 摘要：Flow properties for concentrated solution of chitosan were described in 50%HCOOH,50%CH3COOH, 0.2mol/l HCl and 0.1mol/l CH3COOH+0.1mol/l CH3COONa under the concentration from 2 to 5g/100ml solvent. Flow equations presented in literature,such as Ferry equation,Cross equation and Ballauff equation,were tested from the point of view of the extrapolating method for evaluating the zero shear viscosities.The results of extrapolation were compared with the values measured by falling-ball method. It was shown that the method based on Cross eq-uation gave relatively good results.
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发布时间：2021-03-19 - 摘要：hrough heterophasic adduction between the hydroxyl group of poly (vinyl alcohol)(PVA) and ethylene oxide (EO),hydroxyethyl poly (vinyl alcohol) (HEPVA) with different contents of combined EO were obtained. The relationship between tacticity of PVA and its ethoxylation reactivity was discussed based on structural characterization of HEPVA by 13C-NMR and IR Spectroscopy.The different rates of increase on the content of polyoxyethylene chain in different reaction stages were also disscused.
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发布时间：2021-03-19 - 摘要：The solution-prepared blends of thermotrotropic Liquid crystal copolyester (HTH10) and Nylon-1010 have been investigated by using PLM, DSC and WAXD. It was found that cross polarized micrographs of the blends are as same as the micrographs of HTH10 when the content of HTH10 was over 30%.The crystallinity of Nylon-1010 increased first and then decreased with the increse of HTH10 composition, but the crystallization temperature of Nylon-1010 decreased monotonically. There was a marked derivation of △ Hm from the calculated values when the HTH10 content reached to 30% The results of wide angle X-ray diffraction on the blends demonstrated that the structure of Nylon-1010 was influ-enced significantly at the weight rate of 30/70 for the HTH10 and Nylon-1010 blends.
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发布时间：2021-03-19 - 摘要：Vinyl acetate (VAc) and butyl acrylate (BuA) copolymers were prepared by batch and semi-continuous emulsion polymerization．The microstructure of final copolymers．as well as a binary homopolymer blend obtained by mixing homopoly-mar iatexes．was analysed using 13C-NMR．As expected，the homopolymer blend is characterized by the presence of resonance spectra representing VAc and BuA hom-osequences，no heterosequence resonance spectre representing copolymer chains is observed．The semi-continuous (SC) copolymer is characterized by abundant hetero-equence appearance．which indicates that a true copolymer is formed while in the batch copolymers，the presence of homosequences of both monomers are predomina-nt over heterosequences．13C-NMR measurement of batch copolymers withdrawn at different conversions was then carried out．It clearly shows that in this process，a BuA-rich copolymer is firstly formed with very few VAc units, and a quasx-pure PVAc is yielded at end of copolymerization after BuA exhausted．It is found，how-ever，that VAc polymerized with BuA at beginning of polymerization is presented as mono-and dyad homosequences inserted into long BuA chais．This seems disagr-eeing with the popular VAc homogeneous nucleation mechanism in emulsion polym-erization．which assumes that at beginning of reaction VAc is mainly polymerized in aqueOUs phase due to its large water solubility，and thus to form VAc oligomers．The glass transition temperature (Tg) measurement confirms well the 13C-NMR res-ults．Like homopolymer blend，batch copolymer manifests 2 well separated Tg’s，one is close to that of PBuA．but obviously different from it，which is considered as evidence of the presence of BuA-rich copolymer；another appears at nearly the same temperature as PVAc，and observed only on the samples withdrawn after BuA being completely exhausted as regard to semi-continuous copolymers，only one Tg is observed, which is situated between those of homopolymers．
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发布时间：2021-03-19 - 摘要：Thermotropic liquid crystal poly (4,4'-oxyazoxybenzene ester) (PAB)series with different number of methylene group in flexible unit have been synthesized.The odd-even effect of phase transition temperature has been obviously observed by DSC measurement. The nature and the main factor of odd-even effect have been investigated by dynamic FTIR. The effect of symmetric structure of mesogenic unit in main chain on the phase transition temperature of liquid crystal polymer has been discussed by comparing with poly (2,2'-dimethyl,4,4'-oxyazoxybenzene ester) series.
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发布时间：2021-03-19 - 摘要：Poly-N-Alkyl acrylamide temperature-sensitive hydrogels (poly-N-isopropylamide,poly-N-isopropylacrylamide/methylacrylamide copolymer, poly-N, N-die-thylacrylamide,poly-N,N-diethylacrylamide/N-tert-butylactyamide copolymer and poly-N-n-propylamide) have been prepared.The temperature sensibilities,phase -transition as well as swelling-collapsing properties of the gels are discussed. Based on the performances of poly-N-isopropylacrylamide,the gel-extraction separation is examined to be an effective process for concentration of protein solutions.
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发布时间：2021-03-19 - 摘要：he isothermal and non-isothermal crystallization behaviors of blends o f thermotropic liquid crystalline polyester (LCP) and PET have been studied.The crystallization rate and crytallinity of PET in The blends were signifcantly higher than that of pure PET, which suggests that LCP component acts as a nucleating agent for crystallization of PET. The most efficient nucleation is found at a low content of LCP component (about 2 wt%LCP), implying that the microdomain or aggregating segments of LCP would be the nuclei for PET.
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发布时间：2021-03-19 - 摘要：he concepts of two concentrations,namely segmental and molecular concentrations for polymer blends has been proposed.The former is equivalent to the ordinary volume fraction and the latter is defined as the number of the chain heads in the unit volume for every polymer component.The entropy part of the Flory-Huggins free energy should be represented by the molecular concentration, and the mixing heat part should be represented by the segmental concentration.The two concentrations will be correlated each other by the conformational function of the said polymer chain. When neglecting the conformational fluctuation and ocnsidering only the influence of the molecular concentration fluctuation, the de Gennes scatte-ring function for polymer binary blends has been deducedon the basis of the gene-ral thermodynamical fluctuation theory.
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发布时间：2021-03-19 - 摘要：he structure of Optically active Copolymers of triphenylmethyl methacrylate (TrMA) with methyl methacrylate (MMA) has been studied by 13C-NMR.IR, UV and WAXS. The Compositional heterogenity of the Optically active copolymers having one-handed helicity was found and the Change of specific rotation of Copolymers with TrMA unit Content in Copolymers Showed a S-curve relationship.
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发布时间：2021-03-19 - 摘要：A conventional calibration of size exclusion chromatography (SEC) requires a set of narrowly distributed polymer standards with different molecular weights (M)．In this study，a novel method was proposed，wherein the intrinsic co-nnection between the measured retention volume (V) in SEC and the diffusion coe-fficient (D) in dynamic laser light scattering (LLS)，i.e.，both v and D are related to the same hydrodynamic volume．is utilized to calibrate both SEC and DLS in a single process by using only ONE broadly distributed polymer sample．One broadly distributed polymer standard (NBS706) was used in this study to verify this propo-sed method．The calibration between v and M from this method is fairly comparable to that from the conventional method，and the calibration between D and M is also in agreement with the literature values． With these two calibrations，both of the conversions from the retention volume distribution in SEC and diffusion coefficient distribution inG(D) to molecular weight distribution have been accomplished．This novel method will enable US to use SEC to characterize special polymers where the conventional SEC calibration is not applicable．
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发布时间：2021-03-19 - 摘要：sing SPAN-OP composite emulsifier and K2S2O8-Na2SO3 redox initiator, the inverse emulsion copolymerization of diallyldimethyl ammoniumchloride (DADMAC) and acrylamide (AM) was developed. The monomer reactivity ratios are γDADMAC=0.14±0.11,γAM=5.05±0.66; Under the conditions of total concentration of monomer being 25-45%, initiator concentration being 0.06-0.1%, emulsifier concentration being 5-9% and polymerization temperature being 303K, the kinetic equation of copolymerization can be expressed: Rp=k[M]0.68[I]1.31[E]0.73. In this paper, above results are explained.
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发布时间：2021-03-19
Research Article
- 摘要：hermotropic liquid crystalline copolyesters were synthsized from his(4-hydroxyphenyl) methanone (BHP), tereplithalic acid (TPA), p-hydroxybenzoic acid (PHB) and dihydroxydiphenyl sulfone(DPS). The properties of the copolyesters were characterized by polarized microscope with a hot stage, wide angle X-ray diffraction and differential scanning calorimetry. The results show that the copolyesters containing the BHP exhibit nematic liquid crystallinity.
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发布时间：2021-03-19 - 摘要：A study of the complexes of BM350 with four different alkali metal salts: LIClO4, NaClO4, LiBF4 and LiCF3SO3 by mid-IR and XPS is presented. The results of mid-IR shows that the coordination of canon to polymer makes the C-O-C band become broader and shift slightly. XPS analysis shows that the O atom of two situations can coordinate to Li+(or Na+) and also that this coordination results in the reduction of the electron orbit binding energy of Cl, F and S.
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发布时间：2021-03-19 - 摘要：A complex ionic conductor was prepared by solution complexation of lithium methoxy oligo (oxyethylene) sulfonate (SOL8, where & is the repeating unit of oxyethylene) with comblike copolyether poly [methoxy oligo (oxyethylene)methacrylate-co-acrylamide] [P(MEO16-AM)]. The composition dependences of glass transition temperature,crystallinity as well as conducti-vity of the complex were investigated. DC polarization showed that the complex shows a stable polarization characteristic. Polarization reversing method confirmed that the complex has a cati-onic transference number of 0.99.
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发布时间：2021-03-19 - 摘要：The photopolymerization of acrylamide (AAm) was studied by using N-methacrylyl-N'-pyrimidinopip (MPMP) as sensitizer under UV irradiation.The photopolymerition rate of AAm in water with MPMP as sensitizer is proportional to 0.36th power of MPMP comcentration and 0.88th power of AAm concentration. The overall activation energy for the polymerization is determined to be 5.02Kcal/mol. A super-high MW (107) of PAAm are obtained. The MW is decreased with both the increasing of MPMP concentration and the raising of polymerizat-ion temperature,and inereased with the increase of AAm concentration. Fluoresce-nt analysis indicates that MPMP not only initiates the photopolymerization of vinyl monomers,but also enters into the polymer chains.
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发布时间：2021-03-19 - 摘要：Dimethylaminocthyl methylacrylate (DMAEMA) and its polymer exhibit thermo-sensitive response. The phase separation of their aqueous solution occurs abfruptly when the raising temperature reachs certain degrees. Thus, the temperature of phase separation of 10%,5.0%,2.5%,1.0%(DMAEMA) solution are 40.2,42.5,44.5,52.4℃ respectively. The thermosensitive phase separation also depends on the acidity of solution. The temperature and pH dependence swelling behavior o f slightly crosslinked P(DMAEMA) in water was studied. The adsorption of met-hyl orange for P(DMAEMA) at different temperature was investigated. P(DMAEMA) can he expected as a functional material with thermal and pH-response.
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发布时间：2021-03-19 - 摘要：he acrylamide microemulsion with the mixture of Span 20 and Tween 80 was initiated with γ ray. The polymerization kinetics were derived:R ∝[E]-1.32[D]0.55 [AM]1.14;Mn∝[E]-0.70[D]-0.70[AM]1.34. There is a constant rate period in microemulsion polymerization. In comparsion with the kinetics in other systems, it is known that it is easier to get partly crosslinked polymacrylamide at higher absorbed dose rate and higher monomer conent.
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发布时间：2021-03-19 -
EFFECT OF CONCENTRATION ON THE CRAZE MORPHOLOGY FOR SOLUTION CASTED POLY (METHYL METHACRYLATE) FILMS
摘要：The Morphology of crazes in ultrathin film of poly (methyl methacrylate) prepared by evaporation from different concentration solutions has been observed by TEM. The craze morphology was affected strongly by casting concentrations.When concentration was either too low or too high, only homogeneous deformation zones (DZs) were observed, whose microstructure with their inner microvoids were different from each other. When concentration was within the proper range, both crazes and DZs were observed. With the concentration increasing, the mechanical properties of film were improved. It could also be concluded that fibrillar ceazes initiated in the deformation zones,and the microfibril breakdown took place in the middle of its fibril.- 3
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发布时间：2021-03-19
Research Bulletin
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