聚己内酯-聚丙交酯-聚醚三元共聚高分子微粒及其降解的研究

用乳化－ 溶剂蒸发法制备了聚己内酯－ 聚丙交酯－ 聚醚三元无规共聚物微粒，且与用相同方法制备的聚己内酯（ＰＣＬ） 和聚己内酯－ 聚醚嵌段共聚物微粒的形态进行了比较，讨论了材料的亲水性，以及三元无规共聚物中亲水性聚醚链段的长度及含量对所形成微粒形态的影响。研究结果表明，随着聚合物由疏水性向亲水性转变，所生成微粒的形态则从光滑、多孔、到不规则变化。证明了三元无规共聚物多孔微粒的形成是由于亲水的聚醚链段向水相取向所致。在３７ ℃、ｐＨ７ ．４ 的缓冲液中进行了三元无规共聚物微粒的降解，结果表明，随着降解时间的延长， 三元无规共聚物的分子量逐渐下降，且其中的聚醚链段含量有明显的降低。

环氧树脂与蒙脱土的插层复合研究

报导了一种新型的环氧树脂／蒙脱土插层复合材料。通过阳离子交换的方法将蒙脱土进行有机化处理，使蒙脱土的片层间距从原来的１．３１ｎｍ增加到２．０１ｎｍ。分别用熔融法、溶剂超声法制备了环氧树脂／蒙脱土的插层复合材料，并用ＳＲＤ方法及ＳＥＭ、ＴＥＭ对体系进行了表征。结果表明，环氧树脂／蒙脱土插层体系具有一定的触变性。７．５份蒙脱土插层改性的环氧树脂体系其屈服应力为６３Ｐａ。

聚己内酯微粒的生物降解行为

Spheric polycaprolactone ( P C L) microparticles were prepared by P C L polymerwith an emulsification solvent evaporation technique . Effects of various stabilizers,such asgelatin ,hydrophobically modified polyacrylamide derivative ( P A M) and poly(vinyl alcohol)( P V A) on the morphology and particle size distribution of the P C L microparticles werestudied. The degradation behaviors of the P C L microparticles were compared with andwithoutlipase under p H7 .4 at 37 ±1 ℃. Theresultsshowed thatin the case of using gelatinas a stabilizerthe diameter of the P C L microparticles was in a range of 13 .4 ±4 .7μm . Thefactthat the degradation rate of the P C L microparticles was accelerated in the presence ofenzyme———lipase was evidenced by S E M and G P C measurements. On the other hand ,according to S E M,interference contrast microscopy and X ray diffraction techniques,it wasevidenced that the degradation ofthe P C Lmicroparticlesstarted in theamorphous area ofthe P C L microparticles.

SYNTHESIS OF POLYMER-STABILIZED RUTHENIUM COLLOIDS BY LOW BOILING POINT ALCOHOL REDUCTION

Stable and well-dispersed poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloidal clusters wereprepaxed via the reduction of ruthenium(III) chloride by refluxing with low boiling point alcohols. Investigation of the size ofRu colloids by transmission electron microscopy (TEM) indicated that the average diametes could be controlled in the rangeof 1.2-1.6 nm with relative standard deviations of less than 0.33 by changing the molar ratio of PVP to Ru. The X-rayphotoelectron spectroscopy (XPS) characterization verified the formation of elemental ruthenium colloids.

PREPARATION OF POLYIMIDE-BaTiO3 HYBRID FILMS BY A DISPERSION PROCESS AND THEIR MICROSTRUCTURE

Barium titanate (BaTiO3) powders with particle sizes of 30 similar to 50 nm were prepared from barium stearate, titanium alkoxides and stearic acid by stearic acid-gel method. Dispersing the agglomerate of BaTiO3 nanoparticles into poly(amic acid) solution followed by curing led to the formation of polyimide hybrid films. The hybrid films were transparent and well distributed with BaTiO3 nanoparticles when the BaTiO3 content was less than 1 wt%. Highly loaded hybrid film containing 30 wit % BaTiO3 was tough, had a smooth surface and possessed much higher dielectric and piezoelectric constants than the parent polyimide.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL REACTIVE LADDER-LIKE POLYSILSESQUIOXANE WITH LATERAL BROMOPHENYL GROUPS

A novel soluble, reactive ladder-like polysilsesquioxane (L) with lateral bromophenyl groups was synthesized successfully by stepwise coupling polymerization (SCP) method including preaminolysis, hydrolysis and polycondensation steps. The monomer 3-trichlorosilylpropoxy-4-bromobenzene (M) was first prepared via hydrosilylation reaction catalyzed by dicyclopentadienylplatinum dichloride (Cp2PtCl2). The title polymer (L) was characterized by 1H-NMR, 29Si-NMR, FTIR, X-ray diffraction (XRD), DSC and vapor pressure osmometry (VPO). The experimental results indicate that the polymer (L) possesses a typical ladder-like structure.

CATALYTIC PROPERTIES OF POLYMER-STABILIZED COLLOIDAL METAL NANOPARTICLES SYNTHESIZED BY MICROWAVE IRRADIATION

Catalytic properties of polymer-stabilized colloidal metal nanoparticles synthesized by microwave irradiationwere studied in the selective hydrogenation of unsaturated aldehydes,o-chloronitrobenzene and the hydrogenationof alkenes.The results show that nanosized metal particles synthesized by microwave irradiation have similar catalyticperformance in selective hydrogenation of unsaturated aldehydes,better selectivity to o-chloroaniline in hydrogenation ofo-chloronitrobenzene and higher catalytic activities in hydrogenation of alkenes,compared with metal clusters prepared byconventional heating.The same apparent activation energy(E_a=29 kJ mol^(-(?)) for hydrogenation of (?)-heptene catalyzed withplatinum nanoparticles prepared by both heating modes implied that the reaction followed the same mechanism.

CONCERTED H-BONDING TEMPLATE SYNTHESIS OF AN ORDERED LADDER POLYSILSESQUIOXANE

A novel soluble regular ladder poly（benzoyl-3-aminopropyl） silsesquioxane （LPBAS） was facilely prepared under effective assistance of concerted H-bonding self-assembly of amido groups of side chains and silanol groups, respectively, of a new template monomer [1,3-bis（benzoyl-3-aminopropyl）-1,1,3,3-tetraethoxydisiloxane] （M）. The ordered ladder structure of LPBAS is manifested in： （1） the presence of two Bragg peaks representing the ladder width （d） and ladder thickness （t） in X-ray diffraction （XRD） pattern; （2） narrow base-line width （w = 6） of resonance absorption for -CH2SiO3/2 moiety in 29Si-NMR and （3） high glass transition temperature Tg = 1 12℃ in differential scanning calorimetry （DSC） analysis.

SYNTHESIS AND CHARACTERIZATION OF NOVEL REACTIVE POLYORGANOSILOXANE CONTAINING NITRO GROUPS

A novel reactive polyorganosiloxane containing nitro groups was first prepared by acid-catalyzed equilibration polymerization. The monomer, 3-(4-nitrophenoxy)propylmethyldichlorosilane (NPPMS), was synthesized by hydrosilylation reaction with dicyciopentadienylplatinum(II) chloride (Cp2PtCl2) catalyst in high yield. The synthesized polynitroorganosiloxane, which has potential application as a precursor for synthesizing advanced functional polymers, was characterized by FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, vapor pressure osmometry (VPO) and gel permeation chromatography(GPC).

Modification of Metal Complex on the StereoselectiveHydrogenation of 2,3-Butanedione

The modification of some metal complexes on Pt/Al2O3 clusters leads to remarkable increases in both the activity and the selectivity for meso-2,3-butanediol in the stereoselectivity hydrogenation of 2,3-butanedione.

A NOVEL SUPRAMOLECULAR CLATHRATE OF RODLIKE p-BUTOXYBENZYLIDENE-p′-DODECOXYANILINE TRAPPED WITHIN POLYORGANOSILOXANE PORE

A novel supramolecular polysiloxane clathrate, POS/C, has been preparedby in-situ encapsulating rodlike p-butoxybenzylidene-p ' - dodecoxyaniline (BBDA ) , one kindof Schiff base liquid crystal molecule, within the pore of polyorganosiloxane (POS) whichis prepared by hydrosilylation coupling reaction of polyvinylsilsesquioxane (Vi- T ) withtetramethyldisiloxane (H-MM). Investigation by polarized light microscopy (PLM), differ-ential scanning calorimetry (DSC), infrared spectroscopy (IR), atomic force microscopy(AFM) and molecular simulation gives a preliminary support to the existence of the titlesupramolecular clathrate.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL ALCOHOL-SOLUBLE POLYORGANOSILOXANE CONTAINING AMINO SIDE GROUPS

A novel alcohol-soluble polyorganosiroxane containing amino side groups, poly[3-(4-aminophenoxy)-aminophenoxy) propylmethylsiloxane] (2), was first prepared by the reduction of nitro groups on 4-nitrophenoxypropyl side chains of poly[3-(4-nitrophenoxy)propylmethylsiloxane] (1). The reaction proceeded easily with nearly 100% conversion. The synthesized alcohol-soluble polymer 2, which has potential application as a precursor for preparing advanced functional polymers, was characterized by FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, VPO and GPC, respectively.

POLYMERIZATION MECHANISM OF N-VINYLCARBAZOLE WITH CHIRALLY ORGANIC SALT AS CATALYST

The polymerization mechanism is described by the conductance change with the time during the polymerization. The mechanism can be explained by the equilibrium feature (i.e. main ion-pairs) between the free ions and the ion-pairs dissociated by the organic salt (-) Sp*(+)(+) CSA*(-) (An asterisk represents the chirality) and the scheme of the polymerization process is described mainly by the charge transfer complexes having chiral induction power.

TEMPERATURE DEPENDENCE OF THE FLUORESCENCE SPECTRA OF LADDERLIKE POLYPHENYLSILSESQUIOXANE AND LADDERLIKE 1,4-PHENYLENE-BRIDGED POLYVINYLSILOXANE

Fluorescence spectra of ladderlike polyphenylsilsesquioxane (LPPS) and ladderlike 1,4-phenylene-bridged polyvinylsiloxane (LPPVS) have been measured as a function of temperature (4-55 degreesC), in dilute tetrahydrofuran solution. The excimer (IF) to monomer (I-M) intensity ratio (I-E/I-M) of LPPS dilute solution shows a double linear Arrhenius plot with a break point ascribable to a transition temperature Tt. This behavior has not been found for single chain polyorganosiloxanes. When In/(E) of LPPS was plotted against 1/T, it also gave a double linear plot with one break point, which was found in single chain polyorganosiloxanes. The different behaviors between LPPS and single chain polyorganosiloxanes may be mainly attributed to the relatively rigid double-chain macromolecular backbone of LPPS. However, the 1n(I-E/I-M) of dilute LPPVS solution versus 1/T shows a simple linear variation with a positive slope which confirms our proposition. The difference between the fluorescence results of LPPS and those of LPPVS may possibly derive from their structure differences and cooperative motion in backbone chain bonds.

THE HYDROSILATION REACTION OF LADDERLIKE POLYALLYLSILSESQUIOXANE(ALLYL-T)AND POLYHYDROSILSESQUIOXANE(H-T)

The one plus one (1 + 1) mode of hydrosilation reaction of ladderlike cis-isotatic polyallylsilsesquioxane (Allyl-T) and polyhydrosilsesquioxane (H-T) using dicyclopentadienylplatinumdichloride (Cp2PtCl2) as the catalyst leads to the formation of a new polyorganosiloxane (POS). The presence of nanoscale tubular structure in the product POS was preliminarily proved by IR, H-1-NMR, differential scanning calorimetry (DSC), X-ray diffraction (XRD), gel permeation chromatography (GPC), atomic force microscopy (AFM) and molecular simulation.

Resolution of 3,3'-Dioxo-1,1'(3H,3(H)spirobi[isobenzofuran] -5,6,5'6'-tetracarboxylic acid and Optically active Polyimides thereof

3,3`-Dioxo-1,1'(3H,3'H)spirobi[isobenzofuran]-5,6,5',6'-tetracarboxylic acid 1 was resolved successfully and the corresponding optically active polyimides PI were synthesized. The properties of the optically active PI and the racemic one were investigated. The results showed that the specific rotation of (-)-PI was about two times to that of the (+)-PI, and the regularity of the optically active PI was higher than that of the racemic one.

STRUCTURE AND PROPERTIES OF POLY (N-VINYLCARBAZOLE) OBTAINED VIA ASYMMETRICALLY STEREOSELECTIVE POLYMERIZATION

The structure and properties of poly(N-vinylcarbazole) (PVCZ) obtained via asymmetrically stereoselective polymerization have been studied by using **1H NMR spectra, UV spectra, DSC analysis and GPC. The steric microstructure i.e. the content of isotactic sequences was found to be increased by using AIBN to ( minus )Sp***** plus ( plus )CSA***** minus as the initiators or catalysts and the mole extinction coefficient to be decreased. Bimodal molecular weight distribution (MWD)s of the obtained PVCZs were caused by two propagating species of the free ions and the ion-pairs associated with the organic salts during polymerization. (Author abstract) 19 Refs.

THE HYDROSILYLATION REACTION OF LADDERLIKE POLYVINYLSILSESQUIOXANE WITH 1, 1, 3, 3-TETRAMETHYLDISILOXANE

The hydrosilylation reaction of ladderlike polyvinylsilsesquioxane (Vi-T) with 1, 1, 3, 3-tetramethyldisiloxane (H-MM) catalyzed by dicyclopentadienyl-dichloroplatinium (Cp2PtCl2) was carried out well in tetrahydrofuran (THF) to produce a soluble white solid. This product was characterized by IR, H-1-NMR, C-13-NMR, Si-29-NMR, DSC, X-ray diffraction method, gel permeation chromatography (GPC), vapour pressure osmometry (VPO), atomic force microscopy (AFM) and molecular simulation. These results prove that the product contains nanoscale tubular structure.

SYNTHESIS AND CHARACTERIZATION OF A SOLUBLE LADDERLIKE POLYSILSESQUIOXANE CONTAINING REACTIVE ESTER GROUPS

A novel soluble ladderlike polysilsesquioxane containing reactive ester groups (Ester-T) was synthesized for the first time by stepwise coupling polymerization including preammonolysis, controlled hydrolysis and polycondensation. The monomer, 3-trichlorosilylpropoxy 4-acetoxybenzoate (M), was synthesized by hydrosilylation of allyloxy 4-acetoxybenzoate with trichlorosilane in the presence of dicyclopentadienylplatinum (II) chloride (Cp2PtCl2) catalyst. Combination of FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, XRD, DSC, TGA and VPO methods was used to demonstrate that the polymer obtained has an ordered ladderlike structure. The synthesized Ester-T may have promising applications as a precursor of advanced functional polymers.

SYNTHESIS AND CHARACERIZATION OF LADDER-LIKE POLYDECYLSILSESQUIOXANE

Ladder-like polydecylsilsesquioxane (LPDS) was synthesized by a preamminolysis reaction ofdecyltrichlorosilane with ethylene diamine, followed by hydrolysis and polycondensation reaction. LPDS issoluble in a nonpolar solvent such as heptane and insoluble in a high polar solvent such as methanol. It wascharaterized by IR, ~1H-NMR, ^(29)Si-NMR, GPC and X-ray diffraction.