THERMAL ANALYSIS OF POLYPROPYLENE-b-POLYETHYLENE DIBLOCK COPOLYMERS AND CORRESPONDING BLENDS

Difference in thermal behavior of presumed polypropylene-b-polyethylene block copolymers(PP-PE) and corresponding PP+PE blends was studied. Different views in the literature were unified in our observation that faster cooling rate yielded only one exothermal peak for the blends, while slower cooling rates revealed both PP and PE exothermal peaks. Further details on when a single or double exothermal peaks would appear are discussed. Melting and crystallization temperatures for both PP and PE in blends were found to be a few degrees higher than for PP and PE in block copolymers. Thus, thermal analysis can be used to identify PP-PE block copolymers. These phenomena and the lower △H_f-values of PP and PE in block copolymers than the △H_f-values of pure homo-PP and -PE (for PE even more so) are explained in terms of restricted block movement due to covalent bond between blocks and of crystallization processes in block copolymers. The presence of block structure in the PP-PE samples studied is inferred.     

SYNTHESIS AND CHARACTERIZATION OF A NOVEL BLUE LIGHT EMITTING ROD-COIL DIBLOCK OLIGOMER

Four new rod-coil diblock molecules, which had well-defined para-phenylene oligomers (PPP, from biphenyl toquinquephenyl) as rigid segments and poly(ethylene oxide) (PEO, M_w ca. 750) as flexible segments, were synhesized. Thechemical structure and the number of repeating unit in PEO coil and PPP rod were characterized by ~1H-NMR and MALDI-TOF mass spectromeny. The diblock oligomers showed good solubility in common organic solvents and aggregated in wateras characterized by a blue shift in UV-vis absorption spectra, a red shift in emission spectra, quenching of the fluorescenceand formation of the microfibrilla and fractal-like structures. The formation of different supramolecular structures meant thatthis effort might lead to commercial important highly organized functional materials.     

SYNTHESIS AND CHARACTERIZATION OF POLY（STYRENE—ETHYLENE OXIDE）DIBLOCK COPOLYMERS

Well-defined diblock copolymers of styrene(St) and ethylene oxide(EO) have been prepared by sequential living anionic polymerization of the two comonomers in THF.Diphenyl methyl potassum has been used as initiator.The block copolymers were characterized in detail by methods of size exclusion chromatography(SEC),^1H-NMR,FT-IR,dynamic mechanical analysis(DMA) and WAXD.     

INFLUENCE OF COMPOSITIONAL HETEROGENEITY ON MORPHOLOGY AND PROPERTIES OF SEGMENTED COPOLYMERS

Polyethylene terephthalate(PET)/polycaprolactone(PCL) segmented copolymers with different hard segment contents and a blend of two of them were studied by using DSC, WAXS, TEM and IR techniques and dynamic mechanical, stress-strain and isothermal crystallization measurements. Emphasis was laid on the studies of influence of compositional heterogeneity on the morphology and properties of these segmented copolymers. It was found that the solution cast specimens of the more heterogeneous sample exhibit better segregation of segments, high crystallinity and melting temperature. They have higher thermal stability of mechanical properties at small deformations. However, they are less stable against large deformations and may become softer than the more homogeneous ones.     

SYNTHESIS AND CHARACTERIZATION OF POLY(STYRENE - ETHYLENE OXIDE) DIBLOCK COPOLYMERS

1NTRODUCTIONSinceanionicpolymerizationhasthecharactersofnon--terminationandnon--chainstransferinallpolymersynthesisreactions,themolecularweightandmolecularweitghtdistributionofpolymerscanbecontrolledbyiteasily,soastopreparethepolymerswithexpectedfinestructures.Especially,theattentionisfocusedonthediblockcopolymersmanufacturedbythecomonomerswithdifferent.h....t.r.["ZJ,whichcancompatibilizethetwoincompatiblepolymersascompatibilizer['].InthesystemsofgelorlatexthediblockcOPolymerscanimprovet…     

THE INFLUENCE OF HEAT TREATMENT ON STRUCTURES OF THE AGGREGATED STATE OF POLYAMIDE-1010

The structural parameters of the aggregated state of polyamide (PA)-1010 annealedat various temperatures were computed by means of the desmearing intensity from SmallAngle X-ray Scattering (SAXS) measurements and by using the concept of the distance dis-tribution function. The results indicated that the structural parameters of the aggregatedstate were strongly dependent upon heat treatment conditions and the maximum valuesof the structural parameters were obtained for the samples annealed at T = 175℃. Theparticle size Z annealed at different temperature was ranged between 8.1--12.8nm, and thevalues of the distance distribution function P_(max)(Z) were obtained when Z = 4.0--6.8nm.Using one dimension electron density correlation function (1D EDCF) method long period(L) and thickness of the lamellar (d_0) were estimated and were found to increase with theincrease of the degree of crystallinity.     

RELAXATION IN DOMAINS:STRUCTURE AND SEGMENTAL DYNAMICS OF LC/I DIBLOCK COPOLYMERS

A series of block copolymers consisting of an isotropic (polystyrene) block and a side-chain liquid crystallineblock (LC) have been studied using small-angle X-ray scattering and dielectric spectroscopy. The triblock copolymer (PS-LC-PS) displays an order-to-order transition (OOT) together with the isotropic/nematic transition of the LC phase. The seriesof diblock copolymers show no clear OOT but the phase diagram differs from that of non-LC block copolymers. Thesegmental dynamics as measured with dielectric spectroscopy is dominated by the α and δ relaxation of the LC block. Bothdisplay a WLF like temperature dependence. The relaxation times are influenced by the constraints of the nanoscale domains.They are decreased for the LC confined in the domain as compared to the LC in the continuous matrix.     

INFLUENCE OF DOPING COMPONENT ON THE SOL-GEL PROCESS

ＩＮＦＬＵＥＮＣＥ ＯＦ ＤＯＰＩＮＧ ＣＯＭＰＯＮＥＮＴ ＯＮ ＴＨＥ ＳＯＬ－ＧＥＬ ＰＲＯＣＥＳＳ￥ＹｕｅＨｕａＣＨＥＮ；ＢａｃＦａｎｇＪＩＮ；ＰｉｎｇＷＡＮＧ；ＧｕｏＬｉｎＧＵＯ（ＤｅｐｏｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，Ｉｎｓｔｉｔｕｔｅ...     

THE INFLUENCE OF ACUTE AND CHRONIC HYPOXIA ON THE ELECTROENCEPHALOGRAM OF HUMAN BODY

This report deals with the study of electroencephalograms of 36 subjects who inhaled hypoxic mixture at the sea level (Po_2 is as that at 7000 m above sea level) or in a hypobaric chamber with rapid decompression (as that at 5000—7500 m above sea level) and of 46 subjects who reached high altitude area (5000—8600m) under chronic hypoxia. The characters of the EEGs at rest during photie stimulation, hyperventilation and convalescence after hypoxia were compared in two experiments. The result of experiments shows that in the same individual, the severer the hypoxia, the more obvious the changes on the EEGs. At the same altitude, acute hypoxia causes more obvious changes on the EEGs than chronic one does, but its speed of recovery is faster than that of chronic hypoxia. Under chronic hypoxia, the changes on the EEGs caused by hyperventilation are slighter than those under acute hypoxia. When photic stimulation is given, there is temporary appearance of a waves on the EEGs featuring slow waves under acute     

STUDIES ON GRAFT COPOLYMERIZATION OF DL—LACTIDE ON CORN STARCH AND BIODEGRADABILITY OF THE COPOLYMERS

The starch/D,L-lactide graft copolymers were synthesized by reacting D,L-lactide with corn starch in N,N-dimethylacetamide(DMAM)in the presence of triethylamine(NEt3)and anhydrous lithium chloride.The effect of reaction time and the molar ratio of D,L-lactide to glucose structural unit of starch on monomer conversion(C%),graft(G%)and graft efficiency(GE%)were studied,The C%,G%and GE% could approach 37.3% 179.7%and 68.0%,respectively when the molar ratio of D,L-lactide to glucose structuralunit of starch is 10:1 and the graft copolymerization was carried out at 80-85℃ for 4hr under nitrogen atmosphere.The Fourier transforms infra-red (FTIR) spectroscopy.differential scanning calorimetry(DSC)and X_ray diffraction (XRD) spectroscopy were used in order to characterize the graft copolymers.FTIR spectra show that absorption band at 1740cm^-1 confirmed the formation of ester bond,indicating the starch /D,L-lactide graft copolymers were produced,the DSC characteristic results show the melting temperature of the graft copolymer were elevated slightly as the molar ratio of D,L-lactide to glucose structural units of starch increased and the X-ray diffraction spectra show the synthesized graft copolymers were amorphous.The degradability of graft copolymer was tested with the aid of acid,alkali and microbe such as bacillus subtilis and staphylococcus aureus.The results of water rsistance show the graft copolymer produced can be used as a component of impermeable coating for cardboard.     

THE INFLUENCE OF AXIALLIGANDS ON THE ELECTRONIC ABSORPTION SPECTRA OF PHTHALOCYANINATOIRON(Ⅱ)

Axial ligation in solution by phthalocyaninatolron(Ⅱ)with a varicty of donor ligandshas been widely investigated by measuring the visible spectral changes.It has been foundthat the axial ligation does not influence the Q_ο-οband so much as the Ⅱ-band,the appearance and the red shift of the latter under the action of σ-donation of ligands could be attri-buted to the Charge transfer from the metal d-orbital toward e_σ(π)orbital of PC-ring:e_g(dπ)M→Cg(π)Pc.A linear relation was found to exist between the energy of Q_ο-οand that of Ⅱ-band of ligands containing the same donor atoms(O,N,S,).This may be corre-lated with the electronegativity of donoratoms.     

INFLUENCE OF BACKBONE RIGIDITY ON THE LIQUID CRYSTALLINITY OF MESOGEN-CONTAINING POLYACETYLENES

Two acetylene polymers containing cyanobiphenyl-based mesogens,poly { 10-[ ((4'- cyano-4-biphenylyl ) oxy ) carbonyl] - 1 -decyne } (PA8CN ), which has a relativelyfiexible polyalkyne backbone, and poly {[4-(((12-((4'-cyano-4-biphenylyl)oxy)dodecyl)oxy)carbonyl) phenyl]-acetylene} (PB12CN), which has a fairly rigid poly (phenylacetylene )backbone, were synthesized using respectively WCl_6 and [Rh(nbd)Cl]_2 as the catalysts.PA8CN exhibits enantiotropic interdigitated smectic A phase (S_(Ad)) over a temperaturerange as wide as ca. 100℃, whereas PB12CN is non-mesomorphic, demonstrating thatthe backbone rigidity plays an important role in determining the liquid crystallinity of thepolyacetylenes.     

THE INFLUENCE OF HEAT TREATMENT ON POLYAMIDE－1010 STRUCTURES OF THE AGGREGATED STATE

ＴＨＥＩＮＦＬＵＥＮＣＥＯＦＨＥＡＴＴＲＥＡＴＭＥＮＴＯＮＰＯＬＹＡＭＩＤＥ－１０１０ＳＴＲＵＣＴＵＲＥＳＯＦＴＨＥＡＧＧＲＥＧＡＴＥＤＳＴＡＴＥ￥ＨｏｎｇＦａｎｇＺＨＡＮＧ；ＢａｏＱｕａｎＹＡＮＧ；ＬｉＨｕａＺＨＡＮＧ；ＺｈｉｃｈｅｎＭＯ（Ｃｈａｎ...     

STUDY OF THE INFLUENCE OF HUMIC SUBSTANCES ON THE SORPTION OF RARE EARTH ELEMENTS AT THE KAOLINITE AND BENTONITE SURFACES

ＳＴＵＤＹＯＦＴＨＥＩＮＦＬＵＥＮＣＥＯＦＨＵＭＩＣＳＵＢＳＴＡＮＣＥＳＯＮＴＨＥＳＯＲＰＴＩＯＮＯＦＲＡＲＥＥＡＲＴＨＥＬＥＭＥＮＴＳＡＴＴＨＥＫＡＯＬＩＮＩＴＥＡＮＤＢＥＮＴＯＮＩＴＥＳＵＲＦＡＣＥＳＤＵＪｉｎｚｈｏｕ；ＹＡＮＧＹｏｎｇｐｉｎｇ；...     

STUDIES ON GRAFT COPOLYMERIZATION OF DL-LACTIDE ON CORN STARCH AND BIODEGRADABILITY OF THE COPOLYMERS

1.INTRODUCTIONItiswellknownthataliphaticpolyestershaveahighlevelofbiodegradabilityandstarchwasakindoftotallybiodegradablenaturalpolymermaterial[1,2].Thebiodegradabilityofthealiphaticpolyesters/starchgraftcopolymerswereinvestigatedextensively[3-6].Thepresentpaperrelatestoaprocedureforpreparingastarch/D,L-lactidegraftcopolymer,akindofhydrophobic,totallybiodegradableproducthavinggoodwater-resistanceandmechanicalproperties.ThegraftcopolymersweresynthesizedbyreactingD,L-lactidewithcornstarchi…     

INFLUENCE OF MOLYBDENUM ADDITIVE ONTO THE Co/CuLaZr CATALYSTS

ＩＮＦＬＵＥＮＣＥＯＦＭＯＬＹＢＤＥＮＵＭＡＤＤＩＴＩＶＥＯＮＴＯＴＨＥＣｏ／ＣｕＬａＺｒＣＡＴＡＬＹＳＴＳ￥ＷｅｉＣＨＵ；Ｒ．ＫＩＥＦＦＥＲ；Ａ．ＫＩＥＮＨＥＮＡＮＮ（ＬａｂｏｒａｔｏｉｒｅｄｅＣｈｉｍｉｅＯｒｇａｎｉｑｕｅＡｐｐｌｉｑｕｅｅ，ＵＡ...     

INFLUENCE OF FUNCTIONAL GROUP REACTIONS ON THE PORE STRUCTURE OF MACROPOROUS CROSSLINKED POLYSTYRENE RESINS

The change of the pore structure of styrene-divinylbenzene copolymer caused by the presenceof the functional group has been discribed in this paper. The result indicates that the average poreredius, pore volume and surface area were reduced after the introduction of the functional groups.However, the surfase area of the resin containing--NH_2 or --NHCH_3 group and treated with waterand isopropyl alcohol was inareased prominently in comparison with that of the matrix copolymer. When the strongly polar ion exchange resin absorbs water, its pore diameter increases sharply.But the pore diameter of the weakly polar ion exchange resin does not change very much when itabsorbs water gradually.     

STUDIES ON THE ALCOHOL CHAIN GROWTH AND INFLUENCE OF COBALT ADDITIVE

ＳＴＵＤＩＥＳＯＮＴＨＥＡＬＣＯＨＯＬＣＨＡＩＮＧＲＯＷＴＨＡＮＤＩＮＦＬＵＥＮＣＥＯＦＣＯＢＡＬＴＡＤＤＩＴＩＶＥＣｈｕＷｅｉ，ＸｉｏｎｇＧｕｏｘｉｎｇ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＣａｔａｌｙｓｉｓ，ＤａｌｉａｎＩｎｓｔｉｔｕｔｅｏｆ...     

IONIC SELF-ASSEMBLY AND HUMIDITY SENSITIVITY OF POLYELECTROLYTE MULTILAYERS

Multilayer thin films of alternately adsorbed layers of polyelectrolytes PDDA and PS-119 were formed on bothplanar silica substrates and optical fibers through the ionic self-assembly technique. Intrinsic Fabry-Perot cavities werefabricated by stepwise assembling the polyelectrolytes onto the ends of optical fibers for the purposes of fiber optical deviceand sensor development. Ionically assembled polyelectrolyte multilayer thin films, in which there are hydrophilic side groupswith strong affinity towards water molecules, are a category of humidity-sensitive functional materials. The polyelectrolytemultilayer thin film Fabry-Perot cavity-type fiber optical humidity sensor can work over a wide range from about 0% RH toabout 100% RH with a response time less than 1s.     

STUDIES ON THE REGULAR COPOLYMERS OF POLY (1, 4-PHENYLENETEREPHTHALAMIDE)

Two types of the regular copolymer of poly (1, 4-phenyleneterephthalamide) were synthesized by the low temperature solution polycondensation in NMP-CaCl_2 solvent system, using the piperazine or 2,5-dimethylpiperazine as the third components introduced in the main chain of poly (1, 4-phenyleneterephthalamide). The properties of copolymers were characterized by IR, SEM, X-RAY diffraction, polarizing microscopy, TGA and solubilities.Experimental results showed that the copolymers had good solubility and thermal stability, the concentrated sulfuric acid (～98% ) solution of regular PPTA copolymers had liquid crystalline proper-