聚天冬氨酸的合成

以马来酸酐和碳酸铵为原料,合成了高纯度的聚天冬氨酸(PASP),其结构经IR,TG-DTA等表征。优化反应条件为:马来酸酐200 mmol,n(马来酸酐)∶n(碳酸铵)=1.0∶1.2,于180℃反应1.0 h,收率98.11%,PASP的分子量为8 600。     

化妆品级聚天冬氨酸钠的制备

以L-天冬氨酸为起始原料通过缩合聚合合成了化妆品级的聚天冬氨酸钠(PASP)。 详细考察了聚合温度、聚合时间及催化剂用量对聚合反应的影响,筛选出最优的聚合条件。 利用核磁共振波谱仪(NMR)及凝胶渗透色谱(GPC)对PASP的结构及相对分子质量进行表征,同时也对其耐酸碱性、耐温性及兼容性进行了评估。 结果表明,所制备的PASP颜色浅、气味小、杂质少、品质高并具有良好的耐酸碱性、耐温性及兼容性,达到了化妆品的使用标准,可作为保湿剂添加到化妆品中。     

聚天冬氨酸的合成

缓蚀阻垢;热稳定性;水解稳定性;生物降解性;聚天冬氨酸的合成     

聚天冬氨酸-亚氨基二乙酸聚合物的合成及阻垢性能研究

绿色高效阻垢剂的合成是目前工业循环水领域中的研究热点.以聚琥珀酰亚胺(Polysuccinimide, PSI)、亚氨基二乙酸(Iminodiacetic Acid, IA)为原料,采用接枝共聚法合成了高效水处理剂聚天冬氨酸-亚氨基二乙酸聚合物.利用核磁共振波谱仪和傅立叶变换红外光谱对该聚合物的结构进行表征.通过静态阻垢法测定了聚天冬氨酸-亚氨基二乙酸聚合物在工业循环水中的阻垢性能.结果表明,该聚合物浓度为10 mg/L时,阻CaCO_3垢效率比PASP增加了48%;在15 mg/L时PASP-IA的阻CaSO_4效率已接近100%,显示出了优异的阻垢性能.     

聚天冬氨酸铂的合成与表征

铂类化合物中顺铂、卡铂等目前已经应用于卵巢癌、睾丸癌等肿瘤疾患的治疗,然而这类药物在低剂量下也存在严重的毒副作用[1,2,3].     

聚天冬氨酸钙的合成与表征

螯合的有机酸钙,属于现今钙营养强化剂中的新一代产品[1]。这类钙剂进入血液不是立即解离成钙离子,而是持续离出钙离子供机体利用,从而避免血清中钙离子浓度过高出现高血钙,保证钙元素充分吸收和利用[2,3]。聚天冬氨酸钙具有多肽的化学结构,被人体吸收利用的速度相对要慢、代谢     

聚天门冬氨酸合成过程中的水解反应

L-天门冬氨酸;;聚天门冬氨酸钠盐;聚丁二酰亚胺;水处理;阻垢作用;聚天门冬氨酸合成过程中的水解反应     

改性聚天冬氨酸阻垢剂研究进展

聚天冬氨酸因其具有可生物降解的肽键结构以及优秀的阻垢性能,成为国际公认的环境友好型水处理剂,关于聚天冬氨酸的改性研究也得到了国内外学者的广泛关注.本文综述了近年来聚天冬氨酸改性研究的相关进展,总结了羧基、羟基、磺酸基和酰胺基的引入对聚天冬氨酸性能的影响.     

绿色阻垢剂聚天冬氨酸阻垢性能的实验研究

采用静态与动态实验方法,对聚天冬氨酸的阻垢性能进行了实验研究．静态实验研究表明,在溶液低于60℃的情况下,聚天冬氨酸具有优良的阻垢性能,硬度为600mg／L的溶液添加3mg／L聚天冬氨酸,阻垢率即可超过90％．在800mg／L硬度的情况下,在溶液温度30℃时添加6mg／L聚天冬氨酸,在溶液温度60℃时添加12mg／L聚天冬氨酸,阻垢率均可达到90％以上．CaCO3晶体的扫描电子显微镜结果表明,加入阻垢剂使CaCO3由质地坚硬的柱状晶体转变为松软的不定型体,容易被水冲走而不是沉积在换热表面．动态实验研究表明,成垢溶液添加阻垢剂之后,污垢热阻明显减小,换热表面基本不结垢．     

聚天冬氨酸铁(Ⅱ)、聚天冬氨酸锰(Ⅱ)配合物合成与清除O2(·-)作用

以聚天冬氨酸为配体与不同二价金属离子，在水溶液中制备了聚天冬氨酸铁和聚天冬氨酸锰配合物。通过元素分析、红外光谱对配合物的化学组成与结构进行了初步表征，并利用改进的氮蓝四唑(NBT)光照法测定了其催化O2^.-歧化反应的SOD样活性。所合成的物质具有较高的SOD样活性，且分子量适中、水溶性好、无毒，有广阔的应用前景。     

Synthesis of poly(succinimide) by bulk polycondensation of L‐aspartic acid with an acid catalyst

The bulk polycondensation of L ‐aspartic acid (ASP) with an acid catalyst under batch and continuous conditions was established as a preparative method for producing poly(succinimide) (PSI). Although sulfuric acid, p‐toluenesulfonic acid, and methanesulfonic acid were effective at producing PSI in a high conversion of ASP, o‐phosphoric acid was the most suitable catalyst for yielding PSI with a high weight‐average molecular weight (M_w) in a quantitative conversion; that is, the M_w value was 24,000. For the continuous process using a twin‐screw extruder at 3.0 kg · h⁻¹ of the ASP feed rate, the conversion was greater than 99%, and the M_w value was 23,000 for the polycondensation with 10 wt % o‐phosphoric acid at 260°C. Sodium polyaspartate (PASP‐Na) originating from the acid‐catalyzed polycondensation exhibited high biodegradability and calcium‐ion‐chelating ability. The total organic carbon value was 86 ∼ 88%, and 100 g of PASP‐Na chelated with 5.5 ∼ 5.6 g of calcium ion, which was similar to the value for PASP‐Na from the acid‐catalyzed polycondensation with a mixed solvent © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 117–122, 2000     

Polycondensation Kinetics of Lactic Acid

The direct polycondensation of D ,L ‐lactic acid in the absence and presence of different catalysts at various temperatures has been studied experimentally. Two types of reactions were carried out, one under closed conditions to estimate the equilibrium constant and the other under flow of nitrogen to estimate the polymerization rate constant. A mathematical model was developed based on a suitable kinetic scheme for polycondensation reaction accounting for the rate of water removal. The effects of different operating conditions (temperature and pressure) on the average molecular weight of the polymer have been explored through experiments and model simulations.

     

直接缩聚合成生物可降解材料聚苹果酸研究进展

聚苹果酸是一种具有生物降解性和生物相容性的新型水溶性高分子.合成聚苹果酸的化学方法主要有开环聚合法与直接聚合法.作者综述了直接聚合法合成聚苹果酸的方法、反应机理及性质,并展望了直接聚合法合成聚苹果酸的前景.     

Synthesis of Heterotelechelic Poly(ethylene glycol)-block-poly(succinimide) Possessing Both Acetal and Tert-Butoxycarbonyl-amino Terminals with Narrow Molecular Weight Distribution

A novel heterotelechelic linear block copolymer of poly(ethylene glycol) (PEG) and poly(succinimide) (PSI) possessing both acetal and tert-butoxycarbonyl-amino (Boc-NH) terminals (Acetal-PEG-b-PSI-NH-Boc) with a narrow molecular weight distribution (MWD) was successfully prepared by the nucleophilic attack of triethylamine (TEA) to the poly(β-benzyl L-aspartate) (PBLA) segment of Acetal-PEG-b-PBLA-NH-Boc. Acetal-PEG-b-PBLA-NH-Boc with MWD of 1.07 was prepared by living anionic ring-opening polymerization of β-benzyl L-aspartate N-carboxy-anhydride with α-acetal-ω-amino PEG as a macroinitiator, followed by Boc protection. The subsequent conversion of PBLA segment to PSI was successfully carried out by reacting with the catalytic amount of TEA. The characterization by ¹H NMR, GPC and IR demonstrates that the formation of poly(succinimide) proceeded completely without any remarkable side reactions. Acetal-PEG-b-PSI-NH-Boc thus obtained may have a potential utility as a targetable drug carrier in the field of drug delivery system.     

1H and 13C NMR Analysis of Poly(succinimide) Prepared by Microwave-Enhanced Polycondensation of L-Aspartic Acid

Poly(succinimide) (PSI) is a polymer of aspartic acid with interesting properties and numerous possible uses. Application areas include agriculture, cleaning agents, metallurgy, the building industry, wastewater treatment, medicine, pharmaceuticals, bioengineering, and many more. Therefore, the particular structure analysis is crucial for these purposes, especially considering possible reactions between monomer and solvent used in the polycondensation process. Moreover, utilization of microwave irradiation in such synthesis is conducive to reducing reaction time and improving yield. In this article, the detailed structure analysis of PSI prepared under microwave irradiation conditions as well as a comparison study with thermally synthesized PSI are presented.     

Fabrication of Gene Carrier via Self-assembly of Poly[(dimethylamino)ethyl Methacrylate] and Poly(aspartic acid)-grafted-Poly(ethylene glycol)

A biocompatible complex has been prepared as gene carrier via electrostatic interaction, which is composed of a polycation, that is, poly[(dimethylamino)ethyl methacrylate] end-capped with cholesterol moiety (Chol-PDMAEMA₃₀), along with a polyanion named poly(aspartic acid)-grafted-poly(ethylene glycol) (PASP-g-PEG). The complexes have less cytotoxicity compared to the case of alone Chol-PDMAEMA₃₀ or branched polyethylenimine (PEI) system.

In the present study, biocompatible complexes have been prepared as gene carrier via electrostatic interaction, which is composed of a polycation, that is, poly[(dimethylamino)ethyl methacrylate] end-capped with cholesterol moiety (Chol-PDMAEMA₃₀), along with a polyanion named poly(aspartic acid)-grafted-poly(ethylene glycol) (PASP-g-PEG). We first synthesized polysuccinimide (PSI) via condensation polymerization of aspartic acid, and then used PEG-NH₂ to react with the partial pentacyclic rings of PSI to yield a kind of graft copolymer polysuccinimide-grafted-poly(ethylene glycol) (PSI-g-PEG). After hydrolysis of the residual succinimide units, a new biodegradable and biocompatible graft copolymer PASP-g-PEG was prepared successfully. Chol-PDMAEMA₃₀ was synthesized via oxyanion-initiated polymerization, as reported in our previous literature. We investigated the interactions between every pair among calf thymus DNA, Chol-PDMAEMA₃₀, and PASP-g-PEG by agarose gel retardation assay. The results indicate that the prepared complexes could completely bind DNA and may become more stable during systemic circulation. The complexes have less cytotoxicity compared to the case of alone Chol-PDMAEMA₃₀ or branched polyethylenimine (PEI) system. Furthermore, the physicochemical properties of the complexes were also investigated by zeta potential, transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements. These biodegradable and biocompatible polymeric carriers have potential applications in gene delivery.     

开环聚合-固相缩聚法制备立体嵌段聚乳酸

首先,采用乳酸为引发剂,辛酸亚锡为催化剂,引发丙交酯开环聚合制得具有缩聚活性的L-聚乳酸和D-聚乳酸;然后,将两者熔融共混后进行固相缩聚,合成了一系列立体嵌段聚乳酸。采用核磁共振(NMR)、凝胶渗透色谱(GPC)及差示扫描量热仪(DSC)分析了产物的链结构、重均分子量、热性能,并探讨了均相晶体和立体复合晶体共存情况下的固相缩聚机理。结果表明,固相缩聚产物分子量增长的适宜反应条件为:反应时间30h,较低的催化剂含量,L-聚乳酸质量分数为80%。L-聚乳酸和D-聚乳酸共混物较低的初始立体复合晶体结晶度有利于后续固相缩聚过程中产物分子量的增长;固相缩聚不仅发生在异链之间,而且也发生在同链之间。     

聚丙烯酸/聚丙烯酰胺水溶液复合特性的研究

通过酸度、电导率、粘度、接触角的测定,研究了聚丙烯酸 (PAA) /聚丙烯酰胺 (PAM) 水溶液复合物及复合物膜的结构和性能。结果表明,酸度、温度、浓度和复合比影响PAA/PAM的复合水溶液中大分子链的构象和流体力学体积,适度的氢键作用可以形成均相的复合溶液。经过热处理和未经热处理的聚合物膜表现出了不同的亲水性能。     

Preparation of Highly Fluorinated Poly(ether sulfone)s under Mild Polycondensation Conditions Using Molecular Sieves

Highly fluorinated poly(ether sulfone)s were prepared by a modified polycondensation technique, using a molecular sieve dehydrating apparatus in order to efficiently remove water under mild conditions. Consequently, side reactions were minimized, which resulted in the formation of polymers free of microgels. This reaction was also used to introduce pentafluorostyrene moieties into the polymer to provide crosslinking functionalities.     

SYNTHESIS AND CHARACTERIZATION OF POLY(ASPARTIC ACID) AND ITS DERIVATIVES AS BIODEGRADABLE MATERIALS

ABSTRACT

Three types of modified poly(aspartic acid)s, such as poly(aspartic acid-co-aminocarboxylic acid) (4), alkylamine modified poly(aspartic acid) (5) and crosslinked poly(aspartic acid) (6), were synthesized and calcium-ion chelating ability, hygroscopicity and water absorption were evaluated. The calcium-ion chelating ability of 4 depended on the kind of aminocarboxylic acids and the content of aminocarboxylic acid in the copolymer. The highest value was 3 times higher than that of poly(acrylic acid) with a M_w of 14000. The highly modified PASP, e.g., 50 mol% lauryl amine modified poly(aspartic acid), showed the highest by grogroscopicity among homopoly(aspartic acid)s and modified poly(aspartic acid)s. The maximum swelling of poly(aspartic acid) hydrogel prepared by the γ-irradiation of homopoly(as-partic acid) was 3400 g-deionized water/g-dry hydrogel.