Polypropylene-Clay Nanocomposites: Comparison of Different Layered Silicates

In former studies of the preparation of polypropylene(PP)-clay nanocomposites, different types of layered silicates were used. However, the obtained results were not comparable due to different preparation conditions and types of silicates. The aim of this work was the investigation of the influence of different layered silicates on the properties of the resulting nanocomposites. FT-IR-spectra, SAXS, TEM micrographs, elemental analysis, mechanical properties and surface tension measurements were used for the comparison of the four different layered silicates under investigation.     

Development of Carbazole and Bipyridine Copolymers as Novel Photovoltaic Materials

Summary: A novel acrylate polymer with a carbazole pendant group and bipyridine derivatives as side chains was synthesized, in which derivatives of bipyridine as electro-optic chromophores and carbazole as photoconductive moiety were covalently linked to the acrylate backbone. 2–(Carbazol-9-yl)ethyl methacrylate (CEM) and methacrylic 2-[5-(2-{5,5′-dimethyl-6′-[2-(5-pentylthiophen-2-yl)vinyl]-3,3′-bipyridin-6-yl}vinyl)thiophen-2-yl]ethyl methacrylate (BiPy) were synthesized and then copolymerized to give 99:1, 98:2, 92:8 (mol/mol) CEM/BiPy copolymers. Films of the copolymers blended with poly(3-octylthiophene) (P3OT) or poly(3-decylthiophene) (PDT) and sandwiched between the transparent ITO and Al electrode were examined for photovoltaic properties.     

聚合物存在下纳米银复合材料的制备与表征

以聚丙烯腈聚乙二醇嵌段共聚物PAN-b-PEG-b-PAN为稳定剂, 在超声辐照下成功地制备了分散性较好、尺寸均匀的纳米银颗粒. 用X射线衍射(XRD)、红外光谱(FTIR)、透射电镜(TEM)、紫外-可见吸收光谱(UV-Vis)和热分析(TGA)等对制备的纳米银复合材料进行了表征. 红外结果表明超声辐照并没有破坏聚合物的链结构. 聚合物的引入, 对纳米银颗粒起到了很好的分散保护作用. 用低浓度的硝酸银溶液, 得到粒径较小的纳米银颗粒; 随着硝酸银浓度增大, 纳米银颗粒粒径也增大. 而聚合物的浓度增大时, 所得银纳米颗粒粒径减小. 对银纳米颗粒的形成机理进行了讨论.     

Polymeric Nanocomposites of Polyurethane Block Copolymers and Functionalized Multi‐Walled Carbon Nanotubes as Crosslinkers

Summary: We report on a new route to synthesize polymeric carbon nanotube‐polyurethane (PU) nanocomposites. Multi‐walled carbon nanotubes (MWNTs) functionalized by chemical modification were incorporated as a crosslinker in prepolymer, which was prepared from a reaction of 4,4′‐methylene bis(phenylisocyanate) and poly(ε‐caprolactone)diol. The reinforcing effect of carbon nanotubes in crosslinked MWNT‐PU nanocomposites was more pronounced as compared to that in conventional MWNT‐PU nanocomposites. The optimum content of chemically modified MWNTs for crosslinking with polyurethane was determined to be approximately 4 wt.‐% in our samples, based on observation of a NCO peak in FT‐IR spectroscopy. MWNT‐crosslinked polyurethane containing 4 wt.‐% modified MWNTs showed the highest modulus and tensile strength among the composites and pure PU. The presence of functionalized MWNTs in the polymeric nanocomposite yielded enhancement in the thermal stability due to crosslinking of the MWNTs with PU.

Possible configuration for MWNT‐PU nanocomposite molecules and FT‐IR spectra of samples obtained during reaction of prepolymer with functionalized MWNTs (second step).     

Preparation of Novel Coumarin Cyclic Polymer/Montmorillonite Based Nanocomposites

In present study, the synthesis, characterization, and thermal properties of novel coumarin cyclic polymer poly(3-benzoyl coumarin-7-yl-methacrylate) polymer/montmorillonite based nanocomposites were performed. At the characterizations of nanomaterials FTIR, XRD, DSC and TGA techniques were used. It was determined from XRD measurements that the morphologies of nanocomposites were shifted from exfoliated type to intercalated type when the clay ratio in the coumarin polymer matrix was increased from 1 to 5% level. From DSC analysis, a partial increasing at the glass transition temperatures of nanocomposites was observed related to clay ratios. On the other hand, a positive correlation was observed between the clay ratio and thermal stability of nanomaterials from TGA analysis. Also, the increasing of decomposition temperatures of nanocomposites according to homopolymer was recorded to be 9–17°C.     

叶酸修饰星型端氨基PEG-PLGA纳米胶束的制备及肿瘤细胞靶向作用

合成了星型多臂端氨基聚乙二醇(PEG)/聚乳酸-羟基乙酸(PLGA)两亲性嵌段共聚物(4s-PLGA-PEG-NH₂), 并通过核磁共振和凝胶渗滤色谱法对其结构进行表征; 采用溶剂挥发法制备阿霉素载药纳米胶束, 利用EDC缩合法与叶酸偶联, 得到叶酸修饰的星型端氨基PEG-PLGA纳米胶束; 采用动态光散射、 紫外光谱及透射电镜等手段对纳米胶束进行了表征; 对载药纳米胶束在HeLa细胞中的摄取及细胞毒性进行了初步评价. 结果表明, 经叶酸修饰的星型多臂端氨基PEG-PLGA载药纳米胶束可有效提高HeLa细胞的摄取率以及对HeLa细胞的杀伤率, 表明其可作为一类新型的靶向抗肿瘤药物递送载体.     

新型以咔唑为主链的能量转移型发光聚合物

用Suzuki偶合反应合成了一系列以咔唑为主链，与不同的芳香环和杂环化合物 共聚的新型电致发光无规共聚物．这些共聚物溶于普通的有机溶剂，发较强的荧光 ．咔唑链段为共聚物提供了很好的空穴传输和空穴注入性能．与咔唑共聚的窄能隙 单体，如蒽(ANT)、噻吩(Th)、2，1，3-苯并噻二唑(BTDZ)、2，1，3—苯并硒二唑 (BseDZ)和4，7—二噻吩—2，1，3—苯并噻二唑(DBT)在聚合物中含量小于50％时 成为陷阱中心．还观察到极为有效的分子内能量转移．由于共聚单体的能隙不同， 这些电致发光共聚物的发光范围可覆盖整个可见光谱区．研究结果表明，用咔唑作 为宽带主体，与少量低带隙单体共聚，有可能成为一种合成同时兼有优异空穴注入 特性，又能广泛调节发光颜色的新的发光聚合物体系．     

Novel PEGylated Amphiphilic Copolymers as Nanocarriers for Drug Delivery: Synthesis,Characterization and Curcumin Encapsulation

Amphiphilic polymers can self assemble into micellar nano-particles and can be effectively used as nano carriers for drug delivery. A number of macromolecular delivery systems are under investigation to improve the efficacy of prospective drugs. In this study, seven new co-polymers were synthesized under mild reaction conditions in bulk (without solvent) by chemoenzymatic approach using Candida antarctica lipase (Novozyme 435) and molecular sieves, subsequently these polymers were treated with different long chain bromoalkanes and acid chlorides for attachment of the lipophilic moieties to the backbone polymer via an ether or an ester linkage, respectively in order to make them amphiphilic. These synthesized nano-particles demonstrated high drug loading capacity and have the potential to encapsulate hydrophobic drugs.     

Cuprous Oxide/Nitrogen-doped Graphene Nanocomposites as Electrochemical Sensors for Ofloxacin Determination

Cu₂O/nitrogen-doped grapheme(NG) nanocomposite material was prepared via a facile one step chemical reduction and characterized by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM). A new electrochemical sensor was then fabricated by coating Cu₂O/nitrogen-doped graphene nanocomposite with Nafion on glassy carbon electrode(Cu₂O/NG/Nafion/GCE). The electrochemical response of this modified electrode toward ofloxacin was examined by cyclic voltammetry. The results indicate that Cu₂O/NG/Nafion composite-modified electrode exhibits higher catalytic activity in the electrochemical oxidation of ofloxacin compared with glassy carbon electrode(GCE), Cu₂O/Nafion modified electrode(Cu₂O/Nafion/GCE), and N-doped graphene/Nafion modified electrode(NG/Nafion/GCE). Under optimal conditions, the peak current was found to be linearly proportional to the concentration of ofloxacin in the 0.5-27.5 μmol/L and 27.5-280 μmol/L ranges with a lower detection limit of 0.34 μmol/L, higher sensitivity of 39.32 μA·L·mmol^-1 and a shorter reaction time of less than 2 s. In addition, Nafion can enhance the stability of the modified electrode and prevent some negative species. Thus the modified electrode exhibits good selectivity and a long working life. The Cu₂O/NG/Nafion composite modified electrode shows promising application in electrochemical sensors, biosensors, and other related fields because of its excellent properties.     

基于血红蛋白-纳米磷酸钬复合材料的过氧化氢生物传感器

以Ho2O3为反应物,采用水热法制备了纳米磷酸钬(n-HoPO4),并利用场发射扫描电子显微镜(SEM)、能谱分析(EDS)对其进行形貌表征和元素组成分析.将n-HoPO4和血红蛋白(Hb)复合材料修饰于裸玻碳电极(GCE)表面构建生物传感器,实现了对H2O2的电化学检测.采用循环伏安(CV)和电化学交流阻抗(EIS)技术对修饰电极进行表征,结果表明,Hb/n-HoPO4/GCE对H2O2的还原具有良好的电化学催化效果;n-HoPO4具有良好的导电性和生物相容性,促进了Hb与工作电极间的直接电子转移.研究了不同pH值和电化学扫速对修饰电极响应电流的影响.在优化实验条件下,此生物传感器对H2O2在50 ～ 1000 μmol/L范围内表现出良好的线性关系,相关线性系数R=0.999,检出限为17 μmol/L(S/N=3).此生物传感器具有检测范围宽、稳定性和重现性好、抗干扰能力强等优点,可用于实际样品的检测.     

新型可溶性聚氨酯酰亚胺嵌段共聚物的合成

聚氨酯酰亚胺;多嵌段共聚物;合成;可溶性     

新型PLA-PVP两亲性共聚物的生物相容性

通过溶血试验、动态凝血试验、血小板吸附试验、细胞毒性试验,对新型PLA—PVP两亲性共聚物的生物相容性进行了研究,并考察了共聚物的组成对其生物相容性的影响。结果表明,共聚物的溶血率、凝血程度、血小板吸附和变形情况均符合生物材料生物学评价标准,并且,随单体投料比中亲水性单体NVP舍量增大,共聚物的血液相容性有所提高;细胞毒性试验结果显示共聚物对细胞无毒性,对其生长无明显抑制作用。共聚物中引入亲水性PVP链段后,与单一的PLA材料相比较,生物相容性得到改善。     

基于单壁碳纳米管/Nafion/铜纳米粒子复合材料的多巴胺传感器的研制

通过电沉积金属铜于单壁碳纳米管( SWNTs)/Nafion 修饰的玻碳电极表面构建了一种经济且制备简单的多巴胺传感器。该纳米材料的形貌和成分用扫描电镜和能谱仪表征。不同扫速和pH条件下,以其修饰玻碳电极构建的电化学体系受吸附控制。多巴胺在该电极表面的反应机理为两电子双质子的过程,电荷转移系数α=0.6,电子转移数n=2.67,异相电子转移速率ks=1.38 s-1。在优化条件下,用微分脉冲伏安法检测多巴胺的线性方程为Ipa(μA)=-0.054c(μmol/L)-3.82(R2=0.9988),线性范围5~100μmol/L,检出限为0.014μmol/L(S/N=3)。此传感器制备简单、成本低、灵敏性高、稳定性好、重现性好,检测人尿液中多巴胺的回收率为96.5%~100.4%,相对标准偏差为1.2%~2.4%。     

NiFe_2O_4/NiO纳米复合材料的制备及电催化水氧化性能

以镍铁水滑石为单一前驱体,通过高温焙烧制备了NiFe_2O_4/NiO纳米复合材料,对该纳米复合材料在碱性介质中电催化水的氧化性能进行了研究.结果表明,相比于化学共沉淀法制备的单独NiFe_2O_4、NiO及其物理混合物NiFe_2O_4+NiO,NiFe_2O_4/NiO纳米复合材料具有更高的电催化水氧化活性和更好的循环稳定性.电流密度为10 m A/cm2时过电位仅为364 m V.     

新型PA6/EP/SiO2纳米复合材料的制备

PA6;SiO2;环氧树脂;原位聚合;纳米复合材料     

Novel Nonenzymatic Hydrogen Peroxide Sensor Based on Ag/Cu2O Nanocomposites

The nanocomposites of Ag nanoparticles supported on Cu₂O were prepared and used for fabricating a novel nonenzymatic H₂O₂ sensor. The morphology and composition of the nanocomposites were characterized using the scanning electron microscope (SEM), transmission electron microscope (TEM), energy‐dispersive X‐ray spectrum (EDX) and X‐ray diffraction spectrum (XRD). The electrochemical investigations indicate that the sensor possesses an excellent performance toward H₂O₂. The linear range is estimated to be from 2.0 μM to 13.0 mM with a sensitivity of 88.9 μA mM^?1 cm^?2, a response time of 3 s and a low detection limit of 0.7 μM at a signal‐to‐noise ratio of 3. Additionally, the sensor exhibits good anti‐interference.     

Magnetic Nanocomposites of Coated Ferrites/MOF as Pesticide Adsorbents

Magnetic metal–organic frameworks (MMOFs) are gaining increased attention as emerging adsorbents/water remediation agents. Herein, a facile development of novel MMOFs comprised of coated ferrite nanoparticles (MNPs) and UiO-66 metal–organic framework is reported. In specific, coated Co- and Zn-doped ferrite magnetic nanoparticles were synthesized as building block while the metal–organic framework was grown in the presence of MNPs via a semi-self-assembly approach. The utilization of coated MNPs facilitated the conjugation and stands as a novel strategy for fabricating MMOFs with increased stability and an explicit structure. MMOFs were isolated with 13–25 nm crystallites sizes, 244–332 m²/g specific surface area (SSA) and 22–42 emu/g saturation magnetization values. Establishing the UiO-66 framework via the reported semi-self-assembly resulted in roughly 70% reduction in both magnetic properties and SSA, compared with the initial MNPs building blocks and UiO-66 framework, respectively. Nonetheless, the remaining 30% of the magnetization and SSA was adequate for successful and sufficient adsorption of two different pesticides, 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T), while the recovery with a commercial magnet and reuse were also found to be effective. Adsorption and kinetic studies for all three MMOFs and both pesticides were performed, and data were fitted to Langmuir–Freundlich isotherm models.     

Preparation and Properties of Layered Silicate Nanocomposites Based on Ethylene Vinyl Acetate Copolymers

(Nano)composites based on ethylene vinyl acetate copolymers (EVA) and montmorillonite modified by various alkylammonium cations were processed by mechanical kneading. Polymer intercalation and filler exfoliation were evidenced by X‐ray diffraction and transmission electron microscopy, respectively. Nanocomposites tensile properties showed that Young's modulus increases significantly even at very low content of the organo‐modified filler while preserving high ultimate elongation and tensile stress. The matrix thermal stability in air was increased by 40°C and, interestingly, the obtained nanocomposites present flame retardant properties.     

新型丙烯酸共聚物的合成与表征

以生物试剂磷酸烯醇式丙酮酸钾（PEPK）、丙烯酸（AA）为聚合单体,采用Na2S2O8-Na2S2O5氧化还原引发体系进行温和的水溶液聚合反应,通过平行合成得到了a、b、c 3个系列的PEPK-AA共聚物。通过红外光谱（FT-IR）、核磁共振（13C-NMR）以及共聚物分子量的测定,表征了PEPK-AA共聚物的化学结构...