磷酸酯-碳酸酯共聚物的合成及其微球释药性能研究

在光气、二氯磷酸溴乙酯和双酚A反应后,用三甲胺季铵化侧链,得到了4种两亲性磷酸酯-碳酸酯共聚物.用IR、¹HNMR及元素分析表征了共聚物,测量了水接触角和Mn,研究了其在pH为7.4磷酸盐缓冲溶液中的降解性能.制得了共聚物微球,并研究了微球的形态、粒径及其对抗肿瘤药物5-Fu的释放性能.     

含环氧端基酚酞聚芳醚腈的合成及表征

环氧树脂（ＥＲ）的冲击韧性和耐开裂性较差,因此,提高其抗冲强度而不显著影响力学性能和耐热性能是重要的研究课题．对于ＥＲ的增韧,以前主要采用液态橡胶．近年来,人们开始研究使用高性能热塑性树脂增韧ＥＲ［１～３］．聚醚腈（ＰＣＥ）是目前机械强度最高的热塑性...     

Polycarbonate synthesis by the melt phase carbonate-ester interchange reaction of bisphenol-A diacetate with dimethyl carbonate

The molecular weight of polycarbonate formed by the carbonate-ester interchange reaction of bisphenol-A diacetate (BPAC₂) and dimethyl carbonate (DMC) was found to depend on the composition of the oligomer formed in its first stage. At a [DMC] : [BPAC₂] ratio of 2, an oligomer with relatively higher acetate end group concentration was formed. This upon further polycondensation yielded a polycarbonate of inherent viscosity, 0.2-0.25 dL/g. Upon addition of DMC at a later stage in the oligomer-forming reaction, an oligomer containing relatively higher carbonate end groups could be obtained. These oligomers gave polycarbonates higher inherent viscosity, 0.4-0.5 dL/g. It is therefore proposed that oligomers having carbonate end groups are more reactive in self-polycondensation than those containing acetate end groups. © 1995 John Wiley & Sons, Inc.     

Studies on molecular weight distribution of carbon fiber polymer precursors synthesized using mixed solvents

The molecular weight distributions were estimated for carbon fiber polymer precursors such as poly（acrylonitrile-co -itaconic acid） synthesized by semi batch solution polymerization in mixed solvents media with the azonitrile compounds as initiator under the different ratios of solvent and non solvent from 0.75 to 2.5 in weight.The copolymer was characterized by using Fourier transform infrared spectroscopy（FTIR） and nuclear magnetic resonance（¹H-NMR） analyses.The molecular weight distributions were evaluated by M_v/M_n ratios estimated from viscosity and osmotic measurements,and M_w/M_n estimated from size exclusion chromatography.The molecular weight distributions of these polymers as determined from M_v/M_n and M_w/M_n are 2.9 to 3.2 and 2.0 to 2.5 respectively.The molecular distributions were close to a narrow distribution of 2.0 when the solvent/non-solvent ratio was varied between 1.4 and 2.0.Intrinsic viscosity[?]as a function of molecular weight of poly（acrylonitrile-co-itaconic acid） was evaluated by means of low angle laser light scattering with size exclusion chromatography（SEC-LALLS） and viscometry with SEC（SEC-VISCO）.The relationship between[?]and M_w for poly（acrylonitrile-co-itaconic acid） in DMF at 50℃was[?]= 1.1×10^-5M_w^0.79,where[?]is obtained in dL/g.     

香菇多糖的成分及其分子量研究

从香菇子实体中用0.9%NaCl水溶液、85%乙醇、热水、1%草酸铵、5%NaOH/0.05%NaBH₄和2%NaOH/2%尿素分别提取出四种杂多糖(L-FⅠ-L-FⅣn)和两种葡聚糖(L-FⅤ和L-FⅥn).红外光谱和高效液相色谱分析结果表明杂多糖主要由葡萄糖、葡萄糖醛酸、木糖、甘露糖、半乳糖和鼠李糖组成,而且按照分离过程的进行多糖中葡萄糖含量递增.由光散射和膜渗透压法研究了多糖的重均分子量Mw、均方根旋转半径2>^1/2、第二维利系数A₂及数均分子量M_n.L-FⅡ、L-FⅢ、L-FⅤ及L-FⅥn的M_w值依次为19.7×10⁴、192.3×10⁴、136.4×10⁴和136.7×10⁴,它们的多分散系数-Mw/-Mn在3～5范围.     

The effects of catalyst composition on the catalytic production of dimethyl carbonate

The synthesis of dimethyl carbonate (DMC) by oxidative carbonylation of MeOH has been studied in the presence of various catalyst systems. The effect of catalyst composition on the catalytic activity and product composition is investigated. A three-component catalyst system composed of PdCl₂(PPh₃)₂, Cu(OMe)₂ and Me₄NCl shows synergy effects in terms of the MeOH conversion (26%) and DMC selectivity (95%). The reaction performed in the presence of a single-component catalyst PdCl₂(PPh₃)₂ produces dimethoxy methane (DMM) as a major product with selectivity over 90%, while the addition of Me₄NCl or Cu(OMe)₂ to PdCl₂(PPh₃)₂ results in the increase of DMC selectivity from 2% to 60%.     

Aliphatic Segmented Poly(ether ester amide)s Synthesized from Hexanediamine,Sebacic Acid and Poly(ethylene glycol)s

High molecular weight aliphatic segmented poly(ether ester amide)s(PEEAs) were synthesized via melt polycondensation and chain extension. An oligomeric polyamide(PA) terminated mainly with -COOH groups(HOOC-PA-COOH) was prepared from the reaction of nylon 610 salt with sebacic acid. Melt polycondensation of HOOC-PA-COOH with polyethylene glycol(PEG), such as PEG400, PEG600, PEG1000 and PEG1500, was conducted at 200℃, and several segmented PEEA prepolymers(PrePEEAs) were prepared. Chain extension of PrePEEAs was carried out at 190℃ using 2,2'-(1,4-phenylene)-bis(2-oxazoline) and adipoyl biscaprolactamate as combination chain extenders. Chain extended PEEAs(ExtPEEAs) were characterized by gel permeation chromatography(GPC), Fourier transform infrared spectrophotometer(FTIR), proton nuclear magnetic resonance(¹H NMR), differential scanning calorimetry(DSC), wide angle X-ray scattering(WAXS), thermogravimetry analysis(TGA), and tensile test. The ExtPEEAs exhibited M_n up to 98700, T_m from 164.2℃ to 176.1℃, initial decomposition temperature above 320.6℃, tensile strength up to 34.80 MPa, and strain at break from 111.92% to 353.12%. Aliphatic segmented PEEAs with good thermal and mechanical properties were prepared.     

聚甲基丙烯酸己磺酸钠特性粘数与数均分子量关系

前文已报导了具有较好抗凝血性能的新型聚电解质,聚甲基丙烯酸己磺酸钠(PSSH-MA)的合成,用统计方法对盐存在时PSSHMA溶液的粘性研究及用小角激光光散射法测定的PSSHMA体系的特性粘数和重均分子量的关系。本文进一步用KNAUER膜渗透计测定了该体系的特性粘数与数均分子量的关系^[6],并进一步探讨聚电解质水溶液渗透压测定中的一些问题。     

Efficient synthesis of hydroxyl functioned polyesters from natural polyols and sebacic acid

Amphiphilic hydroxyl functioned polyester（HFP） can be used as compatibilizers for blends of starch and resins.We developed a synthetic method for effective preparation of HFPs.Water was removed by high flow rate N₂ rather than high vacuum during polycondensation of sebacic acid with xylitol,sorbitol,or mannitol in the presence of dehydrative condensation catalyst and the product is with[η]of 27.2 mL/g,M_n of 1903,M_w of 167,693,T_g of -30.5℃,T_m of 44.0℃.Weight loss is 1.73%under 200℃. The integral distributions of molecular weight are 43.6 wt%and 63.8 wt%over 10,000 and 3000,respectively.The results indicated that higher molecular weight HFP was economically synthesized.     

FEC 基电解液对高压正极材料 Li2CoPO4F 电化学性能的影响

本文研究了以氟代碳酸乙烯酯FEC（fluoroethylene carbonate）为共溶剂的电解液对高压正极材料 Li₂CoPO₄F 电化学性能的影响,与碳酸酯基电解液1 mol·L^-1 LiPF₆ EC/DMC=1:1（m:m）相比,1 mol·L^-1 LiPF₆ FEC/DMC=1:1（m:m）可显著提高Li₂CoPO₄F的循环稳定性. 通过线性扫描伏安法（LSV）、扫描电镜（SEM）、X射线光电子能谱（XPS）、X射线衍射（XRD）结合电化学阻抗（EIS）对 FEC 改善 Li₂CoPO₄F 材料循环稳定性的机理进行了探索,结果表明与传统碳酸酯基电解液相比,FEC 基电解液在高压下有着优异的抗氧化性,能够有效抑制电解液的氧化分解. 同时,FEC 基电解液中形成的表面膜具有更高的稳定性,能够抑制电极/电解液界面副反应的发生,提高循环过程中电极材料结构稳定性,从而有益于提高 Li₂CoPO₄F 材料的电化学性能.     

Interventional Radionuclide Therapy of Hepatocellular Carcinoma:Assessment of Intratumoral Retention of HPMA Copolymers

To develop new radiopharmaceuticals for the interventional radionuclide therapy of recurrent hepatocellular carcinoma, poly(HPMA)-APMA-DTPA[HPMA=N-(2-hydroxypropyl) methacrylamide; APMA=N-(3-aminopro-pyl)methacrylamide; DTPA=diethylenetriaminepentaacetic acid] was synthesized by free radical precipitation polymerization in acetone/dimethylsulfoxide with N,N′-azobis(isobutyronitrile) as the initiator. The copolymers were characterized with nuclear magnetic resonance(NMR) spectroscopy and gel permeation chromatography(GPC, M_n=2.2×10⁴, M_w/M_n=1.38). Subsequently, poly(HPMA)-APMA-DTPA was conjugated with ^99mTc radionuclide. Prolonged retention of poly(HPMA)-APMA-DTPA conjugate within the tumor tissues was demonstrated by single-photon emission computed tomography computed tomography(SPECT-CT) at 1, 2, 4 and 24 h following intra-tumoral injection of the conjugate to hepatocellular carcinoma xenografts in mice. DTPA-^99mTc was also synthesized and characterized for comparison. The data suggest that the poly(HPMA)-APMA-DTPA conjugates might be useful for the interventional radionuclide therapy of recurrent hepatocellular carcinoma in humans.     

金属氧化物和盐催化剂上尿素与甲醇合成碳酸二甲酯

在高压釜中采用金属氧化物和盐作为催化剂由尿素与甲醇合成碳酸二甲酯。结果表明,含有结晶水的金属盐比无结晶水金属盐和金属氧化物具有更好的催化活性。采用羟基化合物与硝酸锌组成的二元催化剂,其催化活性显著高于单一催化剂;羟基与硝酸锌之间具有协同催化作用。其中,硝酸锌与SiO2组成的二元催化剂活性最高;硝酸锌与SiO2的质量比为2时,DMC收率可达4.5%。     

侧链含卤素基团聚芳醚酮的合成及性能

通过分子设计, 合成了新型含碘基苯基的双酚单体4-碘苯基对苯二酚(I-Ph-HQ), 利用上述单体与含氟双酚单体(3-三氟甲基)苯基对苯二酚和氟酮通过亲核取代缩聚反应合成了一系列侧链含卤素基团的聚芳醚酮共聚物(PEEK-CF₃-I). 通过FTIR和 ¹H NMR等测试手段, 表征了共聚物的化学结构. 研究了所合成的PEEK-CF₃-I共聚物的介电性能、热性能和机械性能, 探讨了共聚物中含碘侧基和含氟侧基含量的变化及对材料各项性能的影响. 研究表明, 共聚物中含碘侧基含量的增加能够显著提升共聚物的玻璃化转变温度, 其中共聚物材料PEEK-CF₃-I-10%的玻璃化转变温度为153 ℃, 同时材料依然能够保持优异的机械性能和较低的介电常数.     

溶剂对SBS溶液浇铸膜形态结构及性能影响

聚苯乙烯 聚丁二烯 聚苯乙烯 (ＳＢＳ)嵌段共聚物所兼具的高弹性与热塑性来源于其独特的微观相分离结构 ,其形态结构与性能的关系长期以来一直倍受人们的关注 .对于这种微相分离体系 ,除了传统意义上的良溶剂 (对两种嵌段均具有良好的溶解性 ,又称非选择性溶剂 )与不良溶剂外 ,还存在着对两种嵌段中的一种溶解性较好 ,对另一种溶解性较差的选择性溶剂[1,2 ].在溶液浇铸成膜过程中 ,不同溶剂与组成共聚物的两种嵌段的相互作用参数的差异将导致溶液中大分子构象的差异以及微观相分离过程的差异 ,从而影响浇铸膜的形态以及性能[3].本文首先利用…     

Liquid crystalline comb-like polyimides with biphenyl-based side groups

We have synthesized series of comb-like polyimides with mesogenic units in their side groups. Such comb-like polyimides were obtained by polycondensation of aromatic diamines bearing biphenyl-based mesogenic moieties with bicyclo[2,2,2]oct-7-ene 2,3,5,6-tetracarboxylic dianhydride (BCDA). The different diamines, with two lengths of spacer (with 6 and 11 methylene groups), were synthesized in three steps using as mesogenic groups: biphenyl, 4-cyanobiphenyl and 4-(2-methyl-1-butoxy)biphenyl. The synthesis of the polyimides was performed in two steps: polycondensation of a dianhydride with a diamine in N-methyl-2-pyrrolidone at room temperature giving the corresponding polyamic acid, followed by thermal cyclization into the corresponding polyimide. The comb-like polyimides were studied by X-ray diffraction between room temperature and 250°C. Two types of smectic structure were established: SmA₁ for the long spacer and SmC₁ for the short spacer.     

Oxidative Dehydrogenation of 1-Butene to 1,3-Butadiene Using CO2 over Cr-SiO2 Catalysts Prepared by Sol-gel Method

A series of Cr-SiO₂ catalysts with a Cr content(mass fraction) ranging from 0.5% to 9% was prepared by a sol-gel method. The catalysts were characterized by XRD, N₂ adsorption, EDX elemental mapping, Raman spectroscopy, UV-Vis spectroscopy, XPS and H₂-TPR, and their catalytic behavior in the dehydrogenation of 1-butene to 1,3-butadiene(BD) using CO₂ as a soft oxidant was studied. The initial BD yield is well correlated with the amount of Cr⁶⁺ in the fresh catalysts. The highest BD yield of ca. 34% is achieved on the catalysts with 5%-9% Cr at 600℃ and weight hourly space velocity(WHSV) of 4.5 g·g_cat^-1·h^-1. The promoting effect of CO₂ on the BD yield was observed, which can be attributed to the reaction coupling between a simple dehydrogenation of 1-butene and the reverse water-gas shift reaction as well as regaining the oxidation state(lattice oxygen) of reduced Cr³⁺ species due to the mild oxidation ability of CO₂. The Cr-SiO₂ catalyst exhibits higher BD yield than the Cr catalyst supported on SBA-15, which is attributed to the higher amount of Cr⁶⁺ present on the former catalyst.     

不同分子量软链段的聚己内酯型聚氨酯扩链反应动力学研究

合成了一系列不同分子量的聚己内酯,进而制备异氰酸根封端的聚己内酯预聚体,用傅里叶变换红外光谱研究了不同分子量的聚己内酯预聚体与二元醇的扩链反应.扩链反应动力学研究结果表明:聚己内酯预聚体与二元醇的扩链反应均为二级反应;随着软链段反应物料分子量的增加,反应速率常数显著降低,但当分子量超过某一范围后,其对反应速率的影响逐渐减小,趋于不变.对于不同硬链段反应物料含量的扩链反应体系,硬链段反应物料含量越高,软链段反应物料分子量对反应速率的影响越明显,而且,当软链段反应物料分子量超过某一范围后,不同体系的反应速率常数间的差值趋于不变.Arrhenius方程中的指前因子(B)随软链段反应物料分子量的变化关系与速率常数对分子量的依赖关系相同;从反应速率常数对温度的依赖关系可见:表观活化能的直线斜率基本相同,扩链反应的活化能主要与官能团的反应活性相关.     

对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯共缩聚反应及醚键形成的研究

监测了对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯(PET)共缩聚反应过程中1HNMR图谱及特性粘度的变化,对乙酰氧基酯交换反应及乙酰脂肪酯的反应活性进行了研究。并研究了以低分子量PET或对苯二甲酸二乙二醇酯为原料时反应中醚键的形成及其进入共聚酯链的规律性。     

聚苯撑醚砜缩聚过程的研究

本文报导了聚苯撑醚砜碱法缩聚动力学的研究。首先合成了有关的单体及二聚体的模拟化合物,然后进行了反应速率常数的测定。其结果是:(1)两组带有取代基的苯衍生物相互作用时,其反应速率常数等于不带取代基的苯衍生物和带取代基的反应速率常数以及取代基组成相反的另一组速率常数的乘积。(2)对于聚苯撑醚砜缩聚反应必须采用多个反应速率常数来计算动力学过程。     

Polycondensation of benzyl chloride over Ga- and In-modified ZSM-5 type zeolites and Si-MCM-41 or Montmorillonite-K10 supported GaCl3 and InCl3 catalysts

Performance of In- and Ga-modified ZSM-5 type zeolites (namely, In₂O₃/H-ZSM-5, Ga₂O₃/H-ZSM-5, H-GaMFI and H-GaAlMFI) and InCl₃ or GaCl₃ supported on high silica mesoporous MCM-41 or on Mont.-K10 in the liquid phase polycondensation of benzyl chloride to polybenzyl has been investigated. Influence of solvent (namely, dichloroethane, n-heptane and ethanol) and temperature on the rate of polycondensation of benzyl chloride over the catalyst (InCl₃/Si-MCM-41) showing highest polycondensation activity has also been studied. The In- and Ga-containing solid catalysts show good or high activity in the polycondensation reaction at the reaction condition normally employed in the benzylation of aromatic compounds by benzyl chloride. However, the polycondensation is strongly influenced by the solubility of the polybenzyl polymer in the reaction medium and consequently by the solvent used as the reaction medium.