SYNTHESIS OF POLYMERIC β-CYCLODEXTRIN SUPPORTED BY CROSSLINKED POLY(ACRYLAMIDE-co-VINYLAMINE)AND ITS CATALYSIS OF THE HYDROLYSIS OF p-NITROPHENYL ACETATE

Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA) was theninvestigated. The result showed that the polymer-supported β-CD could accelerate the hydrolytic reaction of p-NPA morequickly than β-CD itself and crosslinked poly(acrylamide-co-vinylamine) alone. The acceleration rate of the polymer-supported β-CD was about 10 times as fast as that of free β-CD in 0.01 mol/L phosphate buffer (pH 7.4) containing 32%DMSO at 37±0.1℃ when the molar amount of β-CD units in the polymer was equal to that of free β-CD in the experiments.The enhanced acceleration of thc polymer-supported β-CD should be ascribed to the cooperative contribution of theinclusion effect of β-CD ring and the nucleophilic effect of amino groups on the polymeric support.     

STUDIES ON THE PORE FORMATION MECHANISM OF β-CRYSTALLINE POLYPROPYLENE UNDER STRETCHING*

The pore formation mechanism of,β-crystalline polypropylene under stretching was investigated. The porosity of the samples increases rapidly with stretching, having a maximum at draw ratios around 2 and then decreases monotonically. An abrupt formation process of initial micropores at very low draw ratios was evidenced by in situ SAXS measurements. At the same time the phase transition from ,β-crystal to α-crystal proceeds slowly in the whole deformation process up to large draw ratios around 5. Comparative studies of α- and ,β-crystalline polypropylene samples before stretching indicate that in addition to difference in crystal forms the α- and β-crystalline polypropylene samples exhibit quite different morphological features. There are a lot of interfaces in ,β-crystalline polypropylene samples, which may have a lower density value and can be easily etched by argon ions and penetrated by small molecules. It was concluded from these experimental facts that the pore formation and crystal transition are two independent phenomena during the deformation of β-crystalline polypropylene samples, and phase transition from ,β-crystal to α-crystal could hardly be the origin of pore formation. A defect initiation mechanism was proposed to understand the pore formation behavior of β-crystalline polypropylenes.     

THE EFFECT OF POLAR ADDITIVES ON THE γ RADIATION INDUCED POLYMERIZATION OF STYRENE*

The γ induced polymerization of styrene in the presence of polar additives such as tributylphosphate, triethyl amine and ethanol was studied at dose rate of 5.0×10~(17) eV/ml. min. The re-sult shows that radiation induced polymerization of styrene was sensitized by the three kinds ofadditives at the approximate same rate and the experimental results were in agreement with thetheoretical calculation of WAS equation. The cause of sensitization is due to the proton transfer.     

STUDIES ON THE KINETICS OF PROPYLENE POLYMERIZATION WITH THE COMPLEXTYPE TiCl_3 CATALYST

The active center concentration C_p, the rate constant k_p, and the activation energy of chain propagation E_p in the polymerization of propylene with complex-type TiCl_3-(C_2H_5)_2AlCl catalyst system were studied. The Mn was corrected by (?) value determined by GPC. The values thus obtained for C_p, k_p, and E_p at 50℃were 3.01 mol/mol Ti, 6.27 1/mol·sec, and 5.10 Kcal/mol respectively.The kinetic parameters were compared with those obtained from conventional TiCl_3·AlCl_2 catalyst, showing that the higher activity of the complex-type catalyst over the conventional catalyst is not only due to the higher C_p of the former, but to a greater extent due to the increase of the k_p value.     

RING-OPENING POLYMERIZATION OF ε-CAPROLACTONE BY LANTHANOCENE CATALYSIS*

Ring-opening polymerization of ε-caprolactone (CL) catalyzed bylanthanocenes, O(C_2H_4C_5H_3CH_3)_2YCl (Cat-YCl) and Me_2Si[(CH_3)_3SiC_5H_3]_2NdCl(Cat-NdCl) has been carried out for the first time. It has been found that both yttroceneand neodymocene are very efficient to catalyze the polymerization of CL, giving high molec-ular weight poly (ε-caprolactone) (PCL ). The effects of [cat] / [ε- CL] molar ratio, polymeriza-tion temperature and time, as well as solvents were investigated and polymerization tem-perature is found to be the most important factor affecting the polymerization. The bulkpolymerization gives higher molecular weight PCL and higher conversion than that in solu-tion polymerization. NaBPh_4 was found to promote the polymerization of ε-caprolactone,and thus to increase both the polymerization conversion and MW of poly (ε- caprolactone ).     

A STUDY ON MECHANICAL PROPERTIES OF γ-RAY IRRADIATED HDPE FILLED WITH SERICITE-TRIDYMITE-CRISTOBALITE*

The effect of γ-ray irradiation on the mechanical properties of high densitypolyethylene(HDPE) filled with sericite-tridymite-cristobalite(STC) was studied. The ex-perimental results show that γ-ray irradiation can improve the affinity between HDPE andSTC, and the dispersion of STC in HDPE matrix. Compared with HDPE/STC (80/20)blend, the yield stress and impact strength of irradiated HDPE (10kGy)/STC (80/20) blendare increased from 22.8 MPa and 70J/m to 28.5 MPa and 144J/m. The yield stress andimpact strength of HDPE/irradiated HDPE/STC (48/32/20) are 27.8MPa and 210J/m,respectively.     

STUDIES OF THE INITIATION MECHANISM OF VINYL POLYMERIZATION WITH THE SYSTEM PERSULFATE/N-ALKYL SUBSTITUTED ETHYLENEDIAMINE DERIVATIVES

Effects of N-alkyi substituted ethylenediamine derivatives on vinyl polymerization using persulfate as initiator were studied. The apparent kinetic equations and overall activation energies of acrylamide polymerization were determined using the above mentioned system as initiator. The promoting activities of different diamine derivatives on vinyl polymerization are in the order of tertiary diamine>secondary diamine>primary diamine. Diamines having methyl groups as the substituent on their nitrogen atom possess higher promoting activity than that of having larger alkyl groups. The initial free radicals produced through the redox reaction of persuifate and diamines were studied by spin strapping technique and ESR spectroscopy. The results obtained confirm the fact that the initial free radicals of the diamine species can initiate vinyl polymerization and become the amino end group of the resulting polymers.     

SYNTHESIS OF γ-SUBSTITUTED-PROPYLCYCLOTETRASILOXANES AND THEIR EMULSION COPOLYMERIZATION WITH OCTAMETHYLCYCLOTETRASILOXANE*

Four γ-substituted-propylcyclotetrasiloxanes have been synthesized. Emulsion copolymerizations of these cyclosiloxanes with octamethylcyclotetrasiloxane have been carried out both in cationic and anionic emulsion systems. By way of these reactions, stable emulsions of organosilicon polymers which contain carbonfuctional groups such as γ-hydroxypropyl, γ-acetoxypropyl and γ-chloropropyi have been obtained.The effects of temperature, catalyst and the amount of γ-substituted-propylcyclotetrasiloxanes in emulsion copolymerizations have been studied.     

THE POLYMERIZATION OF d-ELEOSTEARIC ACID IN THE DIPALMITOYLPHOSPHATIDYLCHOLINE-α-ELEOSTEARIC ACID LIPOSOME*

The polymerization of α-eleostearic acid (α-ESA) in the dipalmitoylphosphatidylcholine (DPPC)-α-ESA liposome was studied. The polymerization was carried out by UV irradiation and was kineticfirst order. The rate constant depends on the ratio of DPPC to α-ESA in the liposome. A transitionpoint of reaction rate could be observed in the course of the polymerization, and it appearedearlier with elevated temperature. Before the transition point, the higher the DPPC to α-ESAratio the higher was the reaction rate; while after the transition point, the higher the DPPC to α-ESAratio the lower wa the reaction rate.     

RESEARCH ON THE POLYCONDENSATION KINETICS OF ω-AMINO-ACIDS*

In our previous report, it was discovered that the polycondensation of 9-amino-nonanoic acid follows second order from the beginning up to the extent of reaction, p, around 99%, and after which the reaction changes rapidly to third order. In this paper, we wish to report that this change of the reaction order from second to third occurred also in the polycondensation of 6-aminocaproic acid and 11-amino-undecanoic acid. The transition region lay again at p around 99%. It may be concluded that this is a general rule in the polycondensation of the ω-amino-acids (monomers of the A—B type), and the controversial results that appeared in the literature may be cleared up by our experiments.     

AROMATIC AND HETEROCYCLIC DINITRILES AND THEIR POLYMERS ⅪⅤ. STUDY ON THE CATALYSTS OF THE POLYMERIZATION OF AROMATIC NITRILES*

Various catalysts for the polymerization ot aromatic nitriles were investigated. It was found that Lewis acid-metal is a preferable catalyst system for the polymerization of aromatic nitriles, and the polymerization rate is about 10 times faster than Lewis acid alone. The polymerization rate of benzonitrile catalyzed by Lewis acid and different metals was measured, and the activity of metals was in the following decreasing order ,magnesium, zinc, sodium, calcium. Furthermore, the polymerization of benzonitrile catalyzed by different Lewis acid and zinc was also investigated.     

MULTIPLE MELTING BEHAVIOR OF β-CRYSTALLINE PHASE POLYPROPYLENE

Differential scanning calorimetry and X-ray diffraction experiments on β-nucleated polypropylene were made on the samples crystallized at different temperatures and processed by injection molding. The crystal perfection was shown to vary with crystallization temperature. The observed multiple peaks could be related to a ill-phase with defective inclination of the chains, a recrystallized or original β_2-phase of more perfect inclination, and the α-phase. Injection molded samples could be analyzed from the established DSC interpretation.     

STUDIES ON MISCIBILITY OF POLY (ε-CAPROLACTONE) AND ALIPHATIC POLYCARBONATE BLENDS AND DETERMINATION OF THEIR INTERACTION PARAMETER*

In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.     

POLYMERIZATION OF γ-STEARYL-α,l-GLUTAMATE N-CARBOXYANHYDRIDE USING RARE EARTH COORDINATION CATALYSTS*

A rare earth coordination system was first investigated as a new type of catalyst for the ring-openingpolymerization of α-amino acid N-carboxyanhydrides (NCAs). The results for the polymerization of γ-stearyl-α,L-glutamate(SLG) NCA using neodymium acetylacetonate (Nd(acac)_3)- or neodymium tris(2-ethylhexylphosphonate) (Nd(P_(204))_3)-triethylaluminum-water as catalysts were compared with those using conventional catalysts. It was found that the helicalpoly(γ-stearyl-L-glutamate) with high molecular weight as well as narrow molecular weight distribution can be obtained inthe presence of Nd(acac)_3/AlEt_3-1/2H_2O. The polymer obtained was characterized by IR and NMR spectroscopy.     

EFFECT OF SEQUENCE STRUCTURE ON THE THERMOTROPIC LIQUID CRYSTALLINE PROPERTIES OF POLYESTERAMIDES BASED ON DIMETHYLBENZIDINE, BISPHENOL-A AND ρ-TEREPHTHALYL CHLORIDE*

A series of thermotropic liquid crystalline polyesteramides with differ-ent sequence structure based on dimethylbenzidine (DMBD), bisphenol-A(BPA) and p-terephthalyl chloride (TPC) was synthesized by changing the feeding order of monomers inlow temperature solution polycondensation system. By means of NMR and a computer pro-gram the sequence structure parameters were measured. The effect of sequence structureon liquid crystalline phase transition temperature of PEAs obtained was investigated.     

THE STUDIES ON CHELATING FIBER—THE STUDIES ON THE AMIDOXIMATION OF POLYACRYLONITRILE FIBER

The amidoximation process of commercial polyacrylonitrile fiber was studied. The results showed that it is possible to prepare a chelating fiber, which present high adsorption capability to Au^3+ and reasonable mechanical property,by the amidoximation of PAN fiber,with the increase of reaction time or agent concentration,the coversion of CN group in PAN increases rapidly at first and then increases slowly.When the reaction temperature is higher than that at which the paracrystalline region in the fiber is destroyed, the conversion of CN group increases greatly,but the mechanical property of the fiber begins to be inferior.     

STUDIES ON THE REACTION OF d-ACETAMIDCCINNAMAMIDE WITH TRIS(DIETHYLAMINO)PHOSPHINE

d-Acetamidocinnamamide do not react with P(OMe)_3, with P(NEt_2)_3 they give rise to 2-methyl-4-hydroxy-5-d-[bis(diethylamino)phosphoryl] benzyl imidazole.The pathway is studied for the formation of Ⅰ. The two intermediates(Ⅱ) are isolated.The structures of Ⅰ and Ⅱ are confirmed by IR, ~1H NMR, ~(31)P NMR, Ms.     

TRANSESTERIFICATION OF POLY(ETHYLENE TEREPHTHALATE) WITH POLY(ε-CAPROLACTONE)*

Transesterification of poly(ethylene terephthalate) (PET) with poly(ε-caprolactone) (PCL) was investigated bymeans of NMR spectroscopy, extraction experiments, differential scanning calorimetry (DSC) and phase contrast microscopy(PCM). The ~1H-NMR results show that transesterification takes place in the melt blends and leads to the formation of thePET-PCL copolyester with a chemical structure similar to ethylene terephthalate-ε-caprolactonc copolycster (TCL)synthesized directly from monomers. However, even in the blend that has been transesterified for 8 h, the random PET-PCLcopolyester, PET-PCL copolyester with long PET or long PCL segments and the unreacted PET and PCL homopolymersmay coexist. Due to the low mobility of PET and PCL chains and the high viscosity of the two macromolecules, thetransesterification proceeds with difficulty. Furthermore, PET is incompatible with PCL, the transesterification can onlyoccur at the interface or in the interfacial region between two phases, and finally the reaction can only reach a localequilibrium. These results indicate that in fact the transesterification in the melt blend between two incompatiblehomopolymers could not lead to the formation of completely random or typical block copolyesters.     

STUDIES ON THE KINETICS AND INITIATION MECHANISM OF ACRYLAMIDE POLYMERIZATION USING CERIC/ACETOACETANILIDE SYSTEM AS INITIATOR

It is found that acetoacetanilide possesses very high promoting reactivity towards ceric ion in initiating polymerization of vinyl monomer. The kinetics of acrylamide polymerization and the activation energies were studied. The initiation mechanism of ceric/acetoacetanilide is proposed on the basis of experimental results of FT-IR and ESR.     

STUDIES ON THE INITIATION MECHANISM OF ORGANIC PEROXIDE AND N-METHACRYLOYLOXYETHYL-N-METHYL ANILINE IN METHYL METHACRYLATE POLYMERIZATION

The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied. The kinetics of polymerization of MMA and the ESR spectra of organic peroxide/MEMA system were determined. Based on the ESR study and the end-group analysis by UV spectra of the polymer formed, the initiation mechanism is proposed.