CURE CHARACTERISTICS OF HYDROXYL TERMINATED POLYBUTADIENE PREPOLYMER WITH BLOCKED TOLUENE DIISOCYANATE-Ⅰ

Controlled release of TDI and hence the cure characteristics of several blocked TDI with HTPB are reported. The reactions were followed through viscosity measurements as a function of time and temperature under the catalytic influence of triethylamine. The effect of nature of substituents present on the end capping substrate, temperature, solvent, basicity of catalyst and kinetics thereon have been studied.     

CHARACTERISTICS OF STRUCTURE OF IMPACT COPOLYMERS OF POLYPROPYLENE WITH LOW ETHYLENE CONTENTS

In the present work, the structure and impact properties of copolymers of polypropylenewith low ethylene contents have been investigated. Based on the results of ~(13)C--NMR, FTIR,WAXD, DSC, PLM and SEM, the relationship between impact properties and morphology of thecopolymers has been discussed. The high impact properties of copolymer ICP2 may attribute tothe relatively higher ethylene content and homogeneous ethylene unit distribution. The size andits distribution of spherulite in the copolymers and cycloid cavities dispersed in polypropylenecontinue phase may also be two important factors which affect the impact properties of these materials.     

IONIC CONDUCTIVITY OF METHYLSILOXANE TERMINATED POLYETHYLENE OXIDE WITH LITHIUM PERCHLORATE NETWORK FILMS

Complex films of crosslinked poly(methylsiloxane-co-ethylene oxide) and lithium perchlorate were prepared. These solid state polymeric electrolytes show a markedly higher ionic conductivity, and excellent flexibility. The ionic conductivity of the network films closed to 10~(-5) Scm~(-1) at room temperature. The effects of Li~+ content, species and contents of crosslinking agents, molecular weight of poly(ethylene oxide) and temperature on the ionic conductivity of the network films were also investigated.     

CURE OF A MICROGEL-EPOXY RESIN TWO-PHASE POLYMER WITH ETHYLENE DIAMINE

The curing of a microgel-epoxy resin two phase polymer prepared by in situ copolymerization of unsaturated polyester with acrylic monomer was studied. The unsaturated unit reacted with N—H during the cure of the resin with ethylene diamine. The Michael type reaction was ten times more rapid than the addition of N—H to epoxide.This was accounted for the lower apparent activation energy of the curing of the two phase resin.     

IR STUDIES OF THE SIDE CHAIN ALKYLATION OF TOLUENE WITH METHANOL ON ZEOLITE CATALYSTS

Surface species resulting from the decomposition of methanol on Na—、K—、Rb—、Cs—、BCs—、KCs— and KBCs—X zeolite at 420℃,and the relationship between sur-face species and the side chain alkylation selectivity from toluene with methanol have beenstudied by infrared and gas chromatographic methods.     

OXIDATIVE METHYLATION OF TOLUENE WITH METHANE OVER BASIC ZEOLITE CATALYSTS PROMOTED WITH ALKALI METAL OXIDES

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STUDY ON SYNTHESIS OF HIGH VINYL POLYBUTADIENE WITH TETRAVALENT MOLYBDENUM CATALYST SYSTEM

In this paper the catalytic behaviour of tetravalent molybdenum catalyst system in polymeriza-tion of butadiene is dealt with. The effects of the variety of apions combined with molybdenumatom, the pattern of the substituent R in (i-Bu)_2AlOR and the polymerization conditions on thebutadiene conversion, the molecular weight and its distribution and the microstructure of the polymeralso are studied. It has been found that the catalyst system is significantly active when anions com-bined with the molybdenum atom are acetoxy (CH_3COO-),or ethoxy (C_2H_5O-). Obviously, thevariety of substituent R in (i-Bu)_2 AlOR has a great influence on the catalytic activity. The catalystsystem is inactive if the R group is--COR' (R'is alkyl or aromatic group) or alkyl, whereas the activityof the catalyst system increases if the R group is phenyl or tolyl. With the rise of polymerizationtemperature the polymer molecular weight decreases, the distribution index of molecular weight in-creases and the content of 1,2-unit in polybutadiene reduces.     

CHARACTERISTICS OF CATION—CONDUCTIVE BLENDS PLASTICIZED WITH PROPYLENE CARBONATE

The cation—conductive blends plasticized with propylene carbonate were prepared. The blends exhibited good mechanical strength and single—cation conduction over a wide range of plasticizer composition. The plasticizer not only increases the conductivity of the blends but also decreases the electrochemical interface resistance between the blend and lithium electrode. The carrier in the blends obviously grows in number.     

THE MECHANISM OF CURE REACTION OF 4,4''''-DIAMINODIPHENYL METHANE WITH TETRAGLYCIDYL 4,4''''-DIAMINODIPHENYL METHANE EPOXY

The cure reaction of tetraglycidyl 4,4'-diaminodiphenyl methane (TGDDM) epoxy resin with 4,4'-diaminodiphenyl methane (DDM) has been studied by using DSC. Instead of one exothermic peak, two exothermic peaks, indicative of a complex reaction mechanism, are shown in the DSC curve of TGDDM-DDM mixtures in nonisothermal cure experiments when the content of DDM is lower than stoichiometric ratio. The result of the kinetic analysis of the cure reaction shows that the activation energy of the lower temperature exotherm peak is about 56 kJ/mol and that of the higher temperature exotherm peak is about 136 kJ/mol. The lower temperature cure reaction peak can be attributed to the primary amine-epoxide and secondary amine-epoxide reactions, and the higher temperature cure reaction peak can be attributed to the epoxide-hydroxy reaction under catalysis of tertiary amine in the TGDDM epoxy resin. Because the network density of the cured epoxy resin is determined by these two reactions, the content of DDM has little effect on the glass transition temperature of cured epoxy resin.     

CRYSTALLIZATION CHARACTERISTICS OF β-PHASE CRYSTALS IN COPOLYMERS OF POLYPROPYLENE WITH LOW ETHYLENE CONTENT

Polypropylene copolymers (CPP) containing β-nucleating agent were investigated by differential scanningcalorimetry (DSC), wide-angle X-ray diffraction (WAXD) and polarizing light microscopy (PLM). The results show thathigh content of β-phase crystals can also be formed for CPPs. Like PP homopolymers, the CPPs also have a most favorabletemperature near 132℃ for β-phase crystal growth. The crystallization rate of CPPs containing β-nucleating agent (β-CPP) ismuch greater than that of PP homopolymer containing β-nucleating agent (β-PP homopolymer). The observation ofspherulite morphology of β-CPP and β-PP homopolymer shows that the spherulites of β-CPP are more imperfect than thoseof β-PP homopolymer.     

CRYSTALLIZATION AND MELTING OF POLY（ETHYLENE OXIDE） CONFINED IN NANOSTRUCTURED PARTICLES WITH CROSS-LINKED SHELLS OF POLYBUTADIENE

Small fixed aggregates of a poly(ethylene oxide)-block-polybutadiene diblock copolymer(PEO-b-PB)in THFsolution were obtained by adding a selective solvent for PB blocks,followed by cross-linking the PB shells.Themorphologies of the nanostructured particles with a cross-linked shell were investigated by atomic force microscopy andtransmission electron microscopy.The average behaviors of the PEO crystallization and melting confined within thenanostructured particles were studied by using differential scanning calorimetry experiments.For the deeply cross-linkedsample(SCL-1),the crystallization of the PEO blocks was fully confined.The individual nanoparticles only crystallized atvery low crystallization temperatures(T_cs),wherein the homogenous primary nucleation determined the overallcrystallization rate.For the lightly cross-linked sample(SCL-2),the confinement effect was T_c dependent.At T_c(?)42℃,thecrystallization and melting behaviors of SCL-2 were similar to those of the pure PEO-b-PB diblock copolymer.At T_c>42℃,SCL-2 could form PEO lamellae thicker than those of the pure PEO-b-PB crystallized at the same T_c.     

A STUDY OF LOW-TEMPERATURE CRYSTALLIZATION BEHAVIOR THE cis-1,4 POLYBUTADIENE PREPARED WITH RARE-EARTH CATALYST SYSTEM

The effects of molecular weight and temperature on crystallization processes at low tempera-ture for cis-1,4 polybutadiene prepared with rare-earth catalyst (Ln-PB) have been studied by WAXDmethod. In the range of molecular weight from     

MECHANICAL MODEL FOR TWO-PHASE POLYMER BLEND SYSTEMS WITH THE CHARACTERISTICS OF PHASE INVERSION

For two-phase polymer blend systems, the phase inversion will take place as the blendcomposition is changed. In this paper a mechanical model has been proposed to describe themodulus-composition relation in the phase inversion region. The application of the mechanicalmodel to two polyurethane blend systems has been studied. It was found that the theoreticalprediction for the modulus-composition relation is quite consistent with the experimentalresults. Furthermore, the characteristics of the phase inversion can be determined uniquelyby the parameters involved in the mechanical model.     

INFLUENCE OF MOLECULAR STRUCTURES OF SECONDARY AMINE TERMINATED POLY（ESTER-AMINE）S ON THE CURING PERFORMANCE WITH EPOXY RESIN

Five secondary amine terminated poly(ester-amine)s(defined as PEA)with controlled molecular structures were synthesized through reacting excessive piperazine with phthalicdiglycol diacrylate(PDDA)and 1,1,1-trimethylolpropane triacrylate(TMPTA)at a constant secondary amine/acrylate group ratio of 1.5/1 and at different PDDA/TMPTA molar ratios. Both IR and ~(?)H-NMR spectra indicated that all acrylate groups were consumed in the reaction,based on which the structural parameters were calculated from the ~(?)H-NMR spectra.With decreasing PDDA/TMPTA ratio,the content of secondary amine,degree of branching,molecular weight,T_g and T_d increased accordingly.These polymers were further used as both crosslinkers and flexibilizers for a linear epoxy resin E51 to form cured films under ambient condition.The gel content, relative hardness and T_g of the resulting films increased as PEA molecules changed from linear to highly branching structures.Due to the flexibility of PEA molecules,all the films possessed excellent mechanical performance.     

HYDROBORATION OF ALKYNES WITH DICHLOROBORANE-DIMETHYL SULFIDE——SYNTHESES AND SPECTROSCOPIC CHARACTERISTICS OF gem-DIBORON AND ALKENYLBORON COMPOUNDS

The reactions of alkynes with dichloroborane-dimethyl sulfide (HBCl_2·SMe_2) in the presence of boron trichtoride in pentane have been investigated.Both internal and terminal alkynes react with HBCl_2·SMe_2 in the molar ratio 1:2 at 0℃ to give dihydroborating products, gem-bis (dichloroboryl)alkanes, in good yield. Since the dihydroboration of alkynes is suppressed considerably at lower temperature, the internal alkynes and HBCl_2·SMe_2 react quantitatively in the molar ratio 1.4:1 at-20℃ or -30℃ to give the expected alkenyldichloroboranes.Under the same conditions,the terminal alkynes, however, undergo both monohydroboration and chloroboration.When terminal alkynes react with boron trichloride in the molar ratio 1 :1.1 in pentane, the chloroborating products, 2-chloro-1-alkenyldichloroboranes have been obtained in high yield.All dichloroboranes are readily converted by alcoholysis into the corresponding boronic esters.The resulting compounds have been characterized by IR, ~1H,~(11)B, and ~(13)C N     

ADSORPTION CHARACTERISTICS OF CHLOROPHENOLS FROM AQUATIC SYSTEMS BY HYPERCROSSLINKED RESINS MODIFIED WITH BENZOYL GROUP

A hypercrosslinked polymeric adsorbent （ZH-03） for adsorbing and removing chlorophenolic compounds from their aqueous solutions was studied, including the static adsorption. The equilibrium adsorption data were fit to Freundlich adsorption isothermic models to evaluate the model parameters. Thermodynamic studies on the adsorption of chlorophenolic compounds on ZH-03 indicated that there were chemisorption transitions for 2,4,6-trichlorophenol and physical adsorption processes for 2-chlorophenol and 2,6-chlorophenol, and ZH-03 showed the homogeneous nature of the adsorbent surface. Column adsorption for chlorophenols wastewater shows the advantages of the ZH-03 adsorbent for adsorbing the following chlorophenolic compounds as 2-chlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol. Sodium hydroxide was used for desorpting chlorophenols from ZH-03 and showed excellent performance.     

A CONVENIENT SYNTHESIS OF NEW HYDROXYL CYCLIC AZA COMPOUNDS

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THE SYNTHESIS AND CHARACTERISTICS OF THE COORDINATION COMPOUNDS OF 2-MERCAPTOPYRIDINE-1-OXIDE WITH THE FIPST TRANSITION SERIES METALS

The stability of the coordination compounds of the first transitionseries metal ions(Mn(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ)and Zn(Ⅱ))with 2-mercaptopyridine-1-oxide is reported.A coordination compound CoL_2 is synthesized and characterizedfor the first time.     

MAIN FACTORS STUDY OF THE CONTROLLING GEOCHEMICAL CHARACTERISTICS OF FERROMANGANESE NODULES (Ⅰ)——GEOCHEMICAL CHARACTERISTICS OF FERROMANGANESE NODULES

The geochemical characteristics of ferromanganese nodules have been described in detail by the information study of major elements, trace elements, rare earth elements and infrared spectrophotometer, X-ray diffraction, electronic probing, electronic microscope analysis in 57 ferromanganese nodules of different types from the South China Sea and the Northern Central Pacific Basin. The result shows that (ⅰ) the different types of ferromanganese nodules have different geochemical characteristics; (ⅱ) there is a close relationship between Mn/Fe in ferromanganese nodules and their element content, mineral composition, nodule abundance, tenor (Cu+Co+Ni)%, growth Speed and sedimentary environment. It has suggested that Mn/Fe in nodules can be an indicator of classifying ferromanganese nodule types.     

A METHOD OF PREPARING SPHERICAL NANO-CRYSTAL CELLULOSE WITH MIXED CRYSTALLINE FORMS OF CELLULOSE Ⅰ AND Ⅱ

A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are preparedfrom natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose I and II. The preparationconditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products arealso strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, theultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gelpermeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy(TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the panicle.