Synthesis and Microbiological Stability of Graft Copolymers of N-Vinylpyrrolidone and Chitosan

The kinetics of homogeneous graft polymerization of N-vinylpyrrolidone on chitosan, initiated by ammonium peroxodisulfate, was studied in relation to the reactant concentrations. The reaction orders with respect to the monomer, initiator, and matrix polymer were determined. The compositional nonuniformity and microbiological stability of the copolymer were evaluated.     

Synthesis and Properties of Ruthenium-Coordinated Block Copolymers of 2-Vinylpyridine and Carbazole Derivatives

ABA triblock copolymers consisting of different carbazole-containing blocks and ruthenium complexes were designed with respect to their energy-transfer behavior. The number of 2-vinylpyridine (2VP) units in a polymer chain was tailored from 0 to 20 to observe the size effect of the metal complex as a luminophore or as a luminescence quencher. Photoluminescence and optical absorption measurements as well as the intermolecular energy transfer in the block copolymers were studied. Evidence is provided for a fast energy transfer from carbazole to the ruthenium-coordinated 2VP.     

基于聚乙烯的无规和嵌段接枝共聚物的制备

采用乙烯配位聚合和巯基-烯点击化学相结合的方法制备了羟基封端的线性聚乙烯,末端羟基含量接近100%;利用酰氯与羟基的高效反应,将羟基封端的聚乙烯转化为降冰片烯封端的聚乙烯大单体(PE-NB).使用Grubbs II代催化剂,将大分子单体与降冰片烯(NB)单体进行开环易位共聚,通过调整单体的投料比和加料方式制备了分子量和组成可控的聚降冰片烯-g-聚乙烯(PNB-g-PE)接枝共聚物.其中,无规共聚时,大单体的转化率接近100%,所得无规接枝共聚物的重均分子量为1.79×10~4~3.14×10~4,分子量分布指数为2.09~2.60,聚乙烯链段的质量分数为4.6%~16.8%;而嵌段共聚时,由于空间位阻原因,大单体的转化率约为80%.热分析研究发现,由于空间位阻,接枝共聚物的结晶度较聚乙烯前驱体略有下降,且接枝度越大,结晶能力下降得越多.     

Adsorbent of Noble Metals,Based on Copolymers of Divinyl Sulfide and 4-Vinylpyridine

Russian Journal of Applied Chemistry - Radical copolymerization of divinyl sulfide and 4-vinylpyridine was used to synthesize 3D copolymers having in their structure “pyridine” nitrogen...     

Copolymers of N-Vinylpyrrolidone with N-(p-Acetoxy)phenylmaleimide and Its Oxime: Synthesis and Sorption Properties

Russian Journal of Applied Chemistry - Radical copolymerization of N-vinylpyrrolidone with N-(p-acetoxy)phenylmaleimide and its oxime in the bulk and in a dimethylformamide solution was studied....     

Micellization and Adsorption Parameters of Poly(Propylene Oxide)/Poly(Ethylene Glycol) Block and Graft Copolymers in Aqueous Medium

This work aims to measure the adsorption and micellization parameters of new water soluble nonionic amphiphilic block and graft copolymers based on hydrophilic poly (ethylene glycol) (PEG) and hydrophobic poly (propylene oxide) (PPO) at ambient temperature and normal atmospheric pressure. The chemical composition and molecular weights of the prepared copolymers were determined from ¹H NMR analyses. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The surface tension, critical micelle concentration, and surface activities were determined at different temperatures. Surface parameters such as surface excess concentration, the area per molecule at interface and the effectiveness of surface tension reduction were determined from the adsorption isotherms of the prepared surfactants. Some thermodynamic data for the adsorption and micellization process were calculated and are discussed.     

嵌段共聚物sPS-b-Poly(S-co-E)的合成与表征

用主催化剂茂基三苄氧基钛和茂基三呋喃甲氧基钛与助催化剂甲基铝氧烷(MAO)组成的催化体系研究了先预聚苯乙烯(S)再引入乙烯(E)进行的嵌段共聚合反应,发现总的催化效率随苯乙烯预聚合时间的延长而增加.对嵌段共聚合产物用丁酮、四氢呋喃和氯仿进行顺序萃取分离,得到四氢呋喃中的可溶级分即嵌段共聚物sPS-b-Poly(S-co-E),占总嵌段共聚合产物的30%～50%,其中乙烯链节的含量占总嵌段共聚物的9%～14%.对嵌段共聚物用DSC、WAXD、FTIR、13CNMR和偏光显微等方法进行了表征.     

苯乙烯和乙烯基三甲氧基硅烷嵌段共聚物的制备及表征

以苯乙烯(St)为单体,二硫代萘甲酸异丁腈酯(CPDN)为可逆-加成断裂链转移聚合(RAFT)试剂,合成大分子链转移剂,再加入不同质量的乙烯基三甲氧基硅烷(A171),得到嵌段比不同的共聚物P(St-b-A171)。通过核磁共振谱仪1 H-NMR、凝胶渗透色谱GPC、动态力学分析仪DMA和接触角等方法对P(St-b-A171)结构进行了表征。结果表明:随着nSt/nA171嵌段比从1∶0.15增加到1∶0.45,P(St-b-A71)数均分子量从10400增加到14000,PDI指数从1.42增加到1.58;聚合物成膜后接触角由78.4°增加到89.6°。通过以上分析得出结论,RAFT合成嵌段共聚物的嵌段比对P(St-b-A171)性能有较大影响。     

含聚氧乙烯链段的两亲嵌段共聚物及接枝共聚物的分子设计,合成及性能

论述了由聚烯链段与聚苯乙烯或聚（甲基）丙烯酸酯链段组成的各种嵌段或接枝共聚物（包括二嵌段、两种三嵌段、星型嵌段、多嵌段、二种规整接枝共聚物等）的分子设计及合成,并总结了其两亲性质、络合碱金属离子性及微观相分离等特性。     

Oxidation of 1-(4-nitrophenyl)-2-formylpyrrole

Pyrrole aldehydes interact with oxidizing agents to yield products which are oxidized to different degrees. Pyrrolecarboxylic acids are formed under the influence of silver oxides, an alkaline solution of permanganate, and 2–10% sulfuric acid [1–3]. With peroxidation of hydrogen, 5-unsubstituted pyrrole aldehydes convert to pyrrolone [4], and pyrrol-2-aldehyde converts to succinimide [5]. Chromacetate and chromium sulfuric acids oxidize pyrrole aldehydes to maleinimides [3].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 495–499, April, 1982.     

聚(苯乙烯-b-2-甲基-2-（口恶）唑啉)嵌段共聚物的合成

核磁、离子色谱等测试方法证明 ,以烯丙基型卤代烷烃为引发剂引发的过渡金属催化的活性自由基聚合 ,所得聚合物的端基为卤素[13].由于Ｃ—Ｘ(Ｘ =Ｃｌ,Ｂｒ)键容易断裂 ,因此卤素端基的存在会影响聚合产物的热稳定性 .但由于Ｃ—Ｘ键易于进行各种反应 ,含卤素端基的聚合物可以作为大分子引发剂用于引发其它合适单体反应 ,从而使卤素端基转化为其它基团 ,或合成新型结构的共聚物 .环状单体 2 甲基 2 唑啉 (Ｍｅ ＯＸＺ)亲核性较强 ,可以直接由烯丙基型卤代物引发剂引发活性开环聚合[4 6 ],因此可望以含卤端基的活性聚合产物作为Ｍｅ ＯＸ…     

Graft Copolymerization of 4-Vinylpyridine Onto Partially Carboxymethylated Cellulose. the Degree of Substitution Effect

The graft copolymerization of 4-vinylpyridine (4-VP) onto partially car-boxymethylated cotton (PCMC), having different carboxymethyl contents, was investigated. Under similar reaction conditions, both the graft yield and eerie ion consumption increased by increasing the degree of substitution of carboxymethyl groups of PCMC up to a value of 0.11, beyond which grafting and Ce(IV) consumption decreased. Proof for grafting onto PCMC was provided through IR analysis. the eerie salt-initiated polymerization of 4-VP in the absence of PCMC was also studied. Three series of homo-polymerization reactions of 4-VP directly initiated by eerie ammonium nitrate were carried out with varying reaction times. Each series was run at a different nitric acid concentration. Both conversion and eerie ion consumption, as well as molecular weight, increased with reaction time. Increasing the nitric acid concentration increased both conversion and eerie ion consumption while the molecular weight decreased.     

On the clathratogenic properties of the Ni (NCS)2 (4-Vinylpyridine)4 host

The crystal structure of the non-clathrated -Ni(NCS)₂ (4-Vinylpyridine)₄ complex was solved and refined to R=0.056 (crystal data: a=11.27(3), b=16.86(1), c=32.06(1) Z=8, V=6092 ų;Pbca; d_x=1.30 g. cm^–3). The complex molecule adopts an asymmetric, windmill conformation of the four pyridine ligands. The -phase was used as a solid substrate for clathration of liquid o-, m- and p-xylene, at 25°C. The composition of the products, the enthalpies of clathration and kinetic course of the processes were investigated. The clathration enthalpies, per mole of the host, are equal to 17.07, 14.1 and 21.77 kJ and correspond to the 1.05, 1.11 and 1.30 guest/host molar ratios for, respectively, ortho, meta and para-xylene. The clathration rates follow the order para>ortho>meta. The results are discussed from the structural point of view.     

Simultaneous Dual Living Polymerizations: A Novel One-Step Approach to Block and Graft Copolymers

Just one step is required for the synthesis of block copolymers by simultaneous “living”/controlled ring-opening and radical polymerization initiated by a difunctional (A–B) compound (shown schematically on the right).     

共轭/非共轭嵌段聚苯撑乙烯(PPV)类共聚物的合成与性能

用活性中间体直接引发共轭/非共轭单体聚合的新方法合成了3种PPV嵌段共聚物;用核磁共振谱和FTIR光谱确定了共聚物的结构.引入非共轭片段PS缩短了PPV共轭链的长度,改善了聚合物的溶解性和可加工性.荧光光谱结果表明,嵌段聚合物可使发射峰蓝移,发光的量子效率明显提高,进而调节了发光颜色.     

Synthesis and Characterization of Block Copolymers of Poly(Butylenes Terephthalate-Co-Adipate)

The block copolyesters of poly(butylene terephthalate)(PBT) and poly(butylene adipate)(PBA) were prepared by a novel two-stage method. In the first stage, high molecular weight PBT and PBA were melt mixed in the presence of 1,4-butanediol at 275 °C. In the second stage, vacuum was applied to raise the molecular weight. The extent of transesterification was controlled by the proportion of 1,4-butanediol. The sequence distribution and the thermal properties of the block copolyesters were characterized by NMR and DSC respectively.     

Cell Engineering with Functional Poly(oxanorbornene) Block Copolymers

Cell‐based therapies are gaining prominence in treating a wide variety of diseases and using synthetic polymers to manipulate these cells provides an opportunity to impart function that could not be achieved using solely genetic means. Herein, we describe the utility of functional block copolymers synthesized by ring‐opening metathesis polymerization (ROMP) that can insert directly into the cell membrane via the incorporation of long alkyl chains into a short polymer block leading to non‐covalent, hydrophobic interactions with the lipid bilayer. Furthermore, we demonstrate that these polymers can be imbued with advanced functionalities. A photosensitizer was incorporated into these polymers to enable spatially controlled cell death by the localized generation of ¹O₂ at the cell surface in response to red‐light irradiation. In a broader context, we believe our polymer insertion strategy could be used as a general methodology to impart functionality onto cell‐surfaces.     

Optically Active Alkylvinylpyridines: Synthesis of (+)-(S)-6-(1-Methylpropyl)-2-Vinylpyridine

A generalizable procedure for the preparation of optically active 6-alkyl-2-vinylpyridines from chiral 2-alkylpyridines without loss of optical purity is reported.