可生物降解聚酯酰胺的合成及其对药物缓释作用的研究

通过酰胺二元醇、1，4－丁二醇、己二酸的无规共聚得到了富含酯链段的可生物降解聚酯酰胺。以对硝基苯胺为模型药物，初步研究了不同载药量时的释药行为及分子量对药物释放的影响。     

含有添加剂及LiClO_4的接枝聚酯网络的离子导电性能研究

研究了碳酸丙烯酯（添加量５％）与γ－丁内酯（添加量１０％）对由数均分子量为８００的聚氧化乙烯（ＰＥＯ８００）大单体交联不饱和聚酯（含ＬｉＣｌＯ４）形成的接枝聚酯网络的离子导电性能影响，发现其电导率主要取决于体系中的ＬｉＣｌＯ４浓度．当［ＥＯ链节］／［Ｌｉ＋］＝３０时，室温电导率达最大值，σ２９８Ｋ＝（４．０—４．５）×１０－５Ｓｃｍ－１．这类接枝聚酯网络的玻璃化转变温度（Ｔｇ）同样取决于盐类浓度，而与网络的交联程度无关．网络中的极性添加剂并不显著影响其交联程度与Ｔｇ，但较大幅度提高离子导电性能，这可能与极性添加剂加速载荷离子在导电通道中的迁移性有关．若在上述接枝网络中引入环氧树脂网络，形成接枝聚合物互穿网络，则成膜后的机械强度有进一步提高，同时具有优良的室温电导率，σ２９８Ｋ＝２．４×１０－５Ｓｃｍ－１。     

淀粉与聚丁二酸己二醇酯的反应及其生物降解性研究

合成了一种新型的完全生物降解型材料－淀粉－聚丁己二醇酯共聚物，对影响聚丁二酸己二醇酯的分子量及淀粉与聚丁二酸己二醇酯反应接枝率的主要因素进行了研究，当聚丁二酸己二醇酯酰氯化物与淀粉投料重量比为４：１时，聚酯的接枝率达到３８．２０％，接枝共聚物用枯草芽孢杆菌和金黄色葡萄球菌降解４０ｄ，其失重率达８９．６０％，在土壤中堆埋９０ｄ，接枝共聚物基本完全被降解。     

接枝共聚物结构的理论分析

<正> 在非交联型聚合物中,接枝共聚物的分子结构最为复杂,它既取决于整个共聚物的分子量分布和平均分子量,又与骨架和接枝链的链长分布和平均链长紧密相关。此外,接枝产物的接枝数分布、平均接枝数、接枝点间链段的平均分子量及其分子量分布等都是描述这类共聚物的重要参数。因此,接枝共聚物分子结构的精确表征,是一个尚待解决的研究     

表面接枝聚甲基丙烯酸二甲氨乙酯的pH响应型纤维素纸基材料

使用电子转移再生引发剂原子转移自由基聚合(ARGET ATRP)在滤纸表面接枝聚甲基丙烯酸二甲胺乙酯(PDMAEMA),成功制备了具有p H响应性能的新型纤维素纸基材料.分别在苯甲醚和甲醇中进行该接枝聚合反应,发现在甲醇中接枝效率更高.通过游离引发剂生成的均聚物研究了滤纸表面聚合物侧链的分子量及分子量分布.均聚物的GPC曲线表明聚合物分子量随反应时间增加而增加,分子量分布为1.4~1.6.通过FTIR、SEM及接枝率的测量对改性滤纸进行表征,结果表明PDMAEMA在滤纸表面的接枝聚合具有可控性,通过控制反应时间可控制聚合物在滤纸表面的接枝量.在不同p H条件下对改性滤纸进行静态水接触角的测量,发现其疏水性随p H升高而增大,体现出该纸基材料的p H响应特性.     

生物可降解聚磷腈接枝聚酯共聚物的合成和表征

初步探索了利用酯交换方法制备聚磷腈接枝聚酯共聚物的可能性 .实验发现 ,利用聚酯的端羟基与甘氨酸乙酯全取代的聚磷腈进行酯交换反应 ,是可以获得聚磷腈接枝聚酯共聚物的 .但这种制备过程 ,不仅要求聚酯材料的热稳定性相对较好 ,以及融体粘度较低 ,还要求氨基酸酯取代聚磷腈的热稳定性较好 ,才能获得比较满意的结果 .因此此法更适宜于制备聚磷腈接枝聚己内酯共聚物 ,而且聚己内酯的分子量不宜超过 80 0 0 .     

聚己内酯接枝淀粉纳米晶的制备

通过异氰酸酯与端羟基聚己内酯反应制备端异氰酸酯基预聚体,再接枝到淀粉纳米晶表面,制备了端基分子量可控的聚己内酯接枝淀粉纳米晶。分别用FTIR和1H NMR对所制备的聚己内酯接枝淀粉纳米晶进行表征,结果表明,有少量聚己内酯接枝到淀粉纳米晶表面。XRD结果表明,接枝了少量聚己内酯后的淀粉纳米晶的晶型和结晶度与未接枝的淀粉纳米晶基本一致。聚己内酯接枝淀粉纳米晶的熔融温度由115℃左右提高到122℃左右,并且温度范围变宽。浸润性实验表明,聚己内酯接枝淀粉纳米晶与水不浸润,其表面已具有疏水性。聚己内酯仅接枝在淀粉纳米晶的表面,改善了淀粉纳米晶表面的疏水性能和与聚酯类聚合物的界面相容性。聚己内酯接枝淀粉纳米晶有望用于可降解聚酯类高分子材料,如聚乳酸(PLA)、聚己内酯(PCL)、聚丁二酸丁二醇酯(PBS)等,改善其力学性能和生物降解性能等。     

Fe-Zn双金属氰化物催化环氧丙烷开环聚合的研究

用Fe Zn双金属氰化物 (DMC)催化剂合成了数均分子量 30 0 0～ 12 0 0 0的聚氧化丙烯二元醇 .着重考察了聚合反应的温度、加料方式等对聚合物分子量及分布的影响 ,并初步探讨了Fe Zn双金属氰化物催化环氧丙烷开环聚合的反应特征 .实验发现 ,采用Fe ZnDMC催化剂 ,聚合物分子量可控 ;在较高温度下聚合所得的聚合物分子量分布呈双峰形 ,显示反应体系中至少存在两类活性中心 ,这可能与催化剂中存在两种价态的络合物有关 ,当降低聚合温度时 ,聚合物分子量分布呈单峰形 ,可能是一类活性中心没有引发 ;实验中还发现单体分批加料时聚合物分子量分布较窄 ,而一步加料法所得聚合物分子量分布则很宽     

聚合物接枝反应的动力学分析

<正> 偶联接枝反应,例如阴离子活性聚合物与聚对卤代甲基苯乙烯的接枝反应,以及阳离子活性聚四氢呋喃与聚乙烯基吡啶的接枝反应,近年常见报道。本工作对上述反应进行动力学分析,求得了分子量分布函数、平均分子量、接枝分布、接枝度和接枝率等公式。然后,又将所得公式作适当修正,使之进一步适用于其它类型的接枝反应。     

端羧基酯交换法合成高分子量大豆油基聚酯

以大豆油为原料可高效合成大豆油基二元醇(SOD),通过与二元酸的熔融缩聚获得大豆油基聚酯.然而传统的酯化和酯交换机理无法获得高分子量的聚酯产物,其原因在于反应过程中醇酸单元摩尔比偏离达到高分子量所需的等摩尔比条件.本研究采用一种新型的端羧基酯交换(CET)机理成功合成了高分子量的大豆油基聚酯,首先以过量的可升华二元酸与SOD酯化生成羧基封端预聚物,再通过CET在高真空下脱除过量的二元酸,动态地逼近醇酸等摩尔比条件,从而获得了黏均分子量可达123 kDa的高分子量大豆油基聚酯.该聚酯具有良好的热稳定性和高透明性,其黏附性能可达压敏胶黏剂的商用标准.这种含不饱和脂肪族侧链的聚酯还可通过巯-烯"点击"反应引入季铵盐基团,获得抗菌型大豆油基聚酯.     

Synthesis of high molecular weight polystyrene using AGET ATRP under high pressure

High molecular weight polystyrene (PS) was synthesized by ATRP. Under atmospheric pressure (1 bar), PS with M_n up to 200,000 was prepared using either ARGET or ICAR ATRP. Under high pressure (6 kbar), higher molecular weight PS could be obtained due to accelerated radical propagation and diminished radical termination in polymerization of styrene. Therefore, it was possible to synthesize PS with M_n > 1,000,000 and M_w/M_n < 1.25 using AGET ATRP under a pressure of 6 kbar at room temperature. This is the highest molecular weight linear PS prepared by a controlled radical polymerization.     

Syntheses and characterization of statistical and block fluorinated copolymers with linear and star-like architectures via ATRP

The synthesis of a fluorinated macroinitiator for copper-catalyzed atom transfer radical polymerization (ATRP) is reported, as well as its use for the controlled living polymerization of poly(propylene glycol) methacrylate (PPGM) in MEK at 80 °C. The ATRP system used was efficient for polymerization of the functionalized monomer and the molecular weight of the polymer estimated by NMR spectroscopy was in close agreement with the theoretical molecular weight, as expected for controlled processes. The statistical copolymerization of PPGM or methyl ether poly(ethylene glycol) methacrylate (MPEGMA) with a perfluoroalkyl ethyl methacrylate by copper-mediated ATRP was also investigated and led to copolymers with essentially random incorporation of monomers. The syntheses and characterization of star-like homopolymers of MPEGMA or the fluorinated monomer via ATRP are also reported, as well as an amphiphilic star-like block copolymer containing ethyleneglycol units as the core and fluorinated moieties in the shell. The micellar behavior of this copolymer was investigated as a function of the external environment.     

A Facile Synthesis of Cleavable Block Copolymers via Tandem Polymerizations of NMRP and ATRP

A functionalized compound, 4‐(2‐bromoisobutyryl)‐2,2,6,6‐tetra‐methylpiperidine‐1‐oxyl (Br‐TEMPO), was synthesized and used to synthesize block copolymers through tandem nitroxide‐mediated radical polymerization (NMRP) and atom transfer radical polymerization (ATRP). First, Br‐TEMPO was used to mediate the polymerization of styrene. The kinetics of polymerization proved a typical “living” nature of the reaction and the effectiveness in the mediation of polymerization of Br‐TEMPO. Then the PS‐Br macroinitiator was used to initiate atom transfer radical polymerization (ATRP). A series of acrylates were initiated by PS‐Br macroinitiators in typical ATRP processes at various conditions. The controlled polymerization of ATRP was also confirmed by molecular weight and kinetic analysis. Several cleavable block copolymers of PS‐b‐P(t‐BA), PS‐b‐P(n‐BA), and PS‐b‐PMA, with different molecular weights, were synthesized via this strategy. Relatively low polydispersities (<1.5) were observed and the molecular weights were in agreement with the theoretical ones. Hydrolysis of PS‐b‐P(t‐BA) was carried out, giving amphiphilic block copolymer PS‐b‐PAA without the cleavage of C‐ON bond or ester bond. All the block copolymers have two T_gs as demonstrated by DSC. A typical cleavable block copolymer of PS‐b‐PMA was cleaved by adding phenylhydrazine at 120°C to produce homopolymers in situ.     

Interfacial living radical copolymerization of oil‐ and water‐soluble comonomers to form composite polymer capsules

The suspension copolymerization of methyl methacrylate with hydroxy‐functional poly(ethylene glycol) monomethacrylate (PEGMA) by atom transfer radical polymerization (ATRP) yielded soluble, controlled‐molecular‐weight amphiphilic copolymers (weight‐average molecular weight/number‐average molecular weight <1.3). Despite extensive partitioning of PEGMA into the water phase, copolymers containing up to 24 mol % PEGMA were formed in the oil phase, from comonomer feeds containing 30 mol % PEGMA. Conversions by suspension polymerization were comparable to those obtained by solution polymerization, at over 70%. Suspension copolymers with high PEGMA contents contained high‐molecular‐weight polymer formed by uncontrolled polymerization, unless poly(vinyl pyrrolidone) was added to displace the growing polymer from the interface. The addition of diethylene glycol dimethacrylate gave capsules at 17 mol % PEGMA with ATRP, whereas conventional free‐radical polymerization required 24 mol % PEGMA to form capsules. The lower PEGMA level required for capsule formation with ATRP was attributed to the lower rates of propagation and crosslinking and to improved incorporation of PEGMA into the final gels. Suspension ATRP with 24 mol % PEGMA in the feed gave two‐layer capsule walls consisting of an inner layer visible by transmission electron microscopy and an outer layer visible by both transmission electron microscopy and environmental scanning electron microscopy, which indicated a compositional gradient across the capsule wall. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 156–171, 2006     

Dynamic Monte Carlo Simulation of Graft Copolymers Made with ATRP and Metallocene Catalysts

The synthesis of polyolefin graft copolymers made with coordination polymerization was studied by dynamic Monte Carlo simulation. Narrow molecular weight distribution macromonomers, containing terminal vinyl groups made with atom-transfer radical polymerization (ATRP), were incorporated randomly into the polyolefin backbone. In addition to average molecular weights and polydispersity index, the model predicts the complete molecular weight distribution (MWD) and branching density of the graft copolymer. The effect of the concentration of macromonomers on the grafting efficiency was also studied.     

Atom transfer radical polymerization of ionic liquid monomer: The influence of salt/counterion on polymerization

Understanding the influence of salt/counterion on atom transfer radical polymerization (ATRP) is important to optimize the conditions for ATRP of ionic monomers, such as ionic liquid monomer. This article reports the results of a systematical investigation of the variables associated with ATRP in the presence of different types and amounts of salts, solvents, ligands, and monomers. A series of control ATRP experiments were conducted under various polymerization conditions. The kinetics of the polymerizations, the molecular weight, and molecular weight distribution of the formed polymers were studied by nuclear magnetic resonance and gel permeation chromatography. The results indicated that all of the studied variables influenced the ATRP process to different degrees. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2175–2184     

甲基丙烯酸缩水甘油酯的常温原子转移自由基活性聚合

甲基丙烯酸缩水甘油酯的常温原子转移自由基活性聚合     

Atom Transfer Radical Polymerization of Butadiene Initiated by Benzyl Chloride/MoCl5 Substituted by 1-octanol/PPh3

A novel initiator system, benzyl chloride/MoCl₅ substituted by 1-octanol/triphenyl phosphine (PPh₃), was applied to the atom transfer radical polymerization (ATRP) of butadiene. The characterization revealed the linear increase of the number average molecular weight with the monomer conversion and the rather wide molecular weight distributions of the polymerization products. The microstructure of the butadiene was detected by IR and ¹H-NMR. The chlorine atom at ω –end group of the polymer and the change of valence states of molybdenum detected by UV–Vis spectra revealed that the polymerization accorded primarily with the mechanism of ATRP.     

Synthesis of poly(2‐hydroxyethyl methacrylate) in protic media through atom transfer radical polymerization using activators generated by electron transfer

Atom transfer radical polymerization (ATRP) using activators generated by electron transfer (AGET) was investigated for the controlled polymerization of 2‐hydroxyethyl methacrylate (HEMA) in a protic solvent, a 3/2 (v/v) mixture of methyl ethyl ketone and methanol. The AGET process enabled ATRP to be started with an air‐stable Cu(II) complex that was reduced in situ by tin(II) 2‐ethylhexanoate. The reaction temperature, Cu catalysts with different ligands, and variation of the initial concentration ratio of HEMA to the initiator were examined for the synthesis of well‐controlled poly(2‐hydroxyethyl methacrylate) and a poly(methyl methacrylate)‐b‐poly(2‐hydroxyethyl methacrylate) block copolymer. The level of control in AGET ATRP was similar to that in normal ATRP in protic solvents, and this resulted in a linear increase in the molecular weight with the conversion and a narrow molecular weight distribution (weight‐average molecular weight/number‐average molecular weight < 1.3). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3787–3796, 2006     

梳型接枝共聚物的合成（IV）-氯乙酸降冰片烯甲酯引发苯乙烯、甲基丙烯酸甲酯原子转移自由基聚合的研究

首次报道以自制氯乙酸降冰片烯甲酯（NMCA）为引发剂的苯乙烯、甲基丙烯酸 甲酯的原子转移自由基（ATRP）本体聚合。详细考察了单体转化与反应时间、产物 分子量及分子量分布间的关系。研究发现,此引发引发甲基丙烯酸甲酯ATRP反应所 得聚合物的分子量分布较宽（PDI = 1.80～2.45),且实测值（GPC）与理论值偏差 较大。而NMCA引发的苯乙烯的ATRP反应可得分子量分布较窄（PDI = 1.54)、实验 值（GPC）与理论值基本吻合的产物。单体转化率随反应时间的变化及产物分子量 随单体转化率变化研究证明这一聚合反应具有活性聚合反应特征。产物的NMR分析 证明所合成产物分子中降冰片烯环上双键未参与聚合反应。