纳晶纤维素的功能化及应用

纳晶纤维素(NCC)是一种由价廉的可再生原料制备得到的棒状纳米材料。NCC表面存在的羟基使其可直接进行化学修饰,也可作为生物模板组装负载无机纳米粒子,这赋予了NCC更多的功能。本文对NCC表面组装负载无机纳米粒子的研究进行了重点归纳。NCC具有独特的尺寸结构,优异的强度性质和物理化学性质,毒性较低,没有明显的环境问题,在众多领域有重要的应用价值。本文全面阐述了NCC在复合增强、绿色催化、光电材料、酶固定化、抗菌和医用材料、生物传感器、荧光探针和药物释放等方面的应用,并对其稳定性、相容性和毒性等实际应用性能进行了相应的探讨。     

纳米晶纤维素手性向列型液晶相结构的形成、调控及应用

手性材料作为一种新型功能材料,尤其是其特殊的光学性能以及在传感器、对映体分离领域的潜在应用,已经引起众多科学研究者的广泛关注。纳米晶纤维素(NCC)基手性材料以其丰富的来源、简单的合成工艺、独特的光学性质以及良好的稳定性等成为当前手性材料研究的热点。本文综述了NCC及其手性向列型液晶相的形成机制,重点介绍了NCC手性结构的调控方法,包括NCC性质、环境条件以及添加剂对其手性结构的影响。最后,总结了近几年NCC手性结构在光电材料和模板剂方面的应用研究进展。     

超支化聚合物的合成和自组装研究

超支化聚合物作为树形聚合物的一种,具有独特的结构和性能,受到了科学界和工业界的广泛关注.本文简要总结了研究者们在超支化聚合物的合成、组装及应用方面的部分工作成果.主要包括以下3方面的内容:第一部分介绍了超支化聚合物的合成方法;第二部分介绍了超支化聚合物多维多尺度的自组装结构和组装机理,包括纳米球形胶束,纳米、微米级囊泡,大的复合囊泡,纳米纤维,纳米、微米及宏观管和多孔膜等;第三部分介绍了超支化聚合物在生物医药、细胞模拟及纳米粒子模拟制备等方面的应用.     

全共轭型二茂铁基聚合物

由于二茂铁独特的夹心结构使含二茂铁基聚合物具有独特的电、磁、催化以及氧化还原性能。全共轭型二茂铁基聚合物由于其特殊的π-π电子结构,使其在电学、光学等方面的表现出优越的性质。本文从3个方面（主链型、侧链型和超支化型）介绍了近年来含有二茂铁基团全共轭聚合物的合成及其性能方面的研究进展,讨论了聚合物的结构对溶解性、氧化还原性等方面的影响,并探讨了这一领域存在的问题及可能的发展方向。     

笼型倍半硅氧烷及其在阻燃聚合物中的应用

笼型倍半硅氧烷(POSS)是一种新型的有机-无机杂化材料,是基于化学键作用形成的分子内杂化结构。由于其独特的分子结构,与聚合物复配后形成的杂化材料不但能够明显改善聚合物基体的力学性能、加工性能和光电性能,同时能够显著提高聚合物的耐热性能和燃烧性能。本文简要综述了POSS单体的结构特点及几种在阻燃聚合物中常用到的带有特种结构官能团POSS的合成方法,分析了POSS的加入对聚合物阻燃机理的影响,重点介绍了近年来POSS在阻燃聚合物中的应用研究进展,并展望了今后的研究方向和重点。     

含多面低聚倍半硅氧烷新型杂化聚合物的合成

基于多面低聚倍半硅氧烷（POSS）的杂化聚合物是近年发展起来的一类新型有机/无机杂化材料，性能独特，应用前景广阔。本文综述了含POSS新型杂化聚合物的合成研究进展，涉及自由基溶液聚合、可控活性聚合、开环易位聚合、缩聚和配位聚合。     

SiO2/聚合物核壳型杂化粒子及其空心结构的制备

SiO2/聚合物核壳型杂化粒子及其空心结构以其独特的形貌在药物控制释放、催化剂载体、生物医药等领域应用前景广阔,引起了人们的广泛关注。本文着重从乳液聚合法、仿生矿化法等制备方法角度阐述了SiO2/聚合物核壳型杂化粒子及其空心结构的研究进展。乳液聚合制备SiO2/聚合物核壳型杂化粒子简单易行,一般需要预先合成SiO2纳米粒子,其合成过程通常需要一些非理想的条件,如高温高压、极端pH、昂贵或有毒的有机试剂等,而且预先合成的SiO2粒子无法与聚合物实现100%匹配,即总有纯的聚合物粒子存在。相比之下,原位仿生矿化法制备SiO2杂化粒子不仅在环境条件下可进行,而且能够精确控制其纳米尺度的形态及分级有序结构。目前对材料科学家来讲,要使人工合成SiO2/聚合物杂化粒子实现像自然生物硅那样优异的性能,仍然是很大的挑战。     

超支化聚(酯-酰胺)的合成与流变改性研究

近十几年来 ,超支化聚合物因具有独特的结构和特殊的性能而受到普遍关注[1] .超支化聚合物具有低的熔体粘度 ,与线性聚合物共混可显著改善其加工流变性 ,具有商业应用潜力 .关于超支化聚合物在流变改性方面的应用已有文献报道[2～ 6] ,但目前文献中的大多数单体合成较繁琐且收率不高 ,这已成为制约超支化聚合物应用的瓶颈 ,如何以简便的途径合成超支化聚合物已成为当前研究的重点 .本文设计一条新的合成路线 ,即以 1 ,2 ,4 苯三酸酐、乙醇胺及乙酸酐为原料 ,以高的收率得到了单体N ( 2 乙酰氧基乙基 ) N ( 2′ ,4′ 二羧基苯甲酰基 )胺 (…     

脂肪型超支化聚酯的端基改性研究

近年来 ,超支化聚合物以其独特的结构和性能而受到广泛的重视 ,已成为 2 1世纪高分子科学研究的重要方向[1～ 4 ] .超支化聚合物通常是通过 AB2 型单体的缩聚来合成的 ,由于超支化聚酯的单体容易合成 ,因此 ,有关超支化聚酯的研究最为深入 .目前所报道的脂肪型超支化聚酯都是以 2 ,2 -二甲醇基丙酸为原料来合成的 ,Malstrom等 [5～ 7]系统研究了该聚合物的合成及结构 .最近 ,Johansson[8]采用丙烯酰氯对该聚合物端基改性 ,获得了可用于紫外光固化的涂料 ,但是所采用的合成及提纯方法都很复杂 ,并且需要很长的反应时间 .本文采用一种新的…     

可交联含氟聚醚醚酮的合成

聚醚醚酮 (PEEK)是一种耐热等级高、耐化学药品、耐辐射并有优异的电性能及机械性能的特种工程塑料 .由于其综合性能优异 ,PEEK在航空航天、通信、电子和机械化工等领域获得成功应用 [1] .含氟芳香聚合物以其独特的性能而成为低介电常数微电子和低损耗光波导器件极具潜力的材料 [2 ] .聚合物良好的溶解性虽对光电集成电路的加工十分重要 ,但也要满足多层化操作过程 ,还要考虑器件成型后的抗化学药品性 .因而 ,在聚合物中引入可交联组分是必要和可行的方法 .另外 ,交联后的聚合物将有更高的玻璃化转变温度 (Tg)、更好的尺寸稳定性和防开…     

Dispersions of nanocrystalline cellulose in aqueous polymer solutions: structure formation of colloidal rods

The steady-state shear and linear viscoelastic deformations of semidilute suspensions of rod-shaped nanocrystalline cellulose (NCC) particles in 1.0% hydroxyethyl cellulose and carboxymethyl cellulose solutions were investigated. Addition of NCC at the onset of semidilute suspension concentration significantly altered the rheological and linear viscoelastic properties of semidilute polymer solutions. The low-shear viscosity values of polymers solutions were increased 20-490 times (depending on polymer molecular weight and functional groups) by the presence of NCC. NCC suspensions in polymer solutions exhibited yield stresses up to 7.12 Pa. Viscoelasticity measurements also showed that NCC suspended polymer solutions had higher linear elastic moduli than the loss moduli. All of those results revealed the gel formation of NCC particles and presence of internal structures. The formation of a weak gel structure was due to the nonadsorbing macromolecules which caused the depletion-induced interaction among NCC particles. A simple interaction energy model was used to show successfully the flocculation of NCC particles in the presence of nonadsorbing polymers. The model is based on the incorporation of the depletion interaction term between two parallel plates into the DLVO theory for cubic prismatic rod shaped NCC particles.     

金属纳米粒子/聚合物体系的稳定性及其机理

金属纳米粒子由于其小的尺寸和大的比表面积等特点，使其具有独特的热性能、电性能、磁性能和光性能，以及很强的团聚趋势。因此金属纳米粒子是否被稳定在纳米尺度内，是它们能否表现出独特性能的关键。本文综述了非离子聚合物、聚电解质、两亲聚合物、双亲水聚合物、树状聚合物对金属纳米粒子的稳定作用及其稳定机理的研究进展。     

金属纳米粒子/聚合物体系的稳定性及其机理

金属纳米粒子由于其小的尺寸和大的比表面积等特点,使其具有独特的热性能、电性能、磁性能和光性能,以及很强的团聚趋势。因此金属纳米粒子是否被稳定在纳米尺度内,是它们能否表现出独特性能的关键。本文综述了非离子聚合物、聚电解质、两亲聚合物、双亲水聚合物、树状聚合物对金属纳米粒子的稳定作用及其稳定机理的研究进展。     

Flexible and iridescent chiral nematic mesoporous organosilica films

Nanocrystalline cellulose (NCC) has been used to template ethylene-bridged mesoporous organosilica films with long-range chirality and photonic properties. The structural color of the organosilica films results from their chiral nematic ordering, can be varied across the entire visible spectrum, and responds to the presence of chemicals within the mesopores. To synthesize these materials, acid hydrolysis was used to remove the NCC template without disrupting the organosilica framework. The resulting mesoporous organosilica films are much more flexible than brittle mesoporous silica films templated by NCC. These materials are the first of a novel family of chiral mesoporous organosilicas with photonic properties.     

Insertion of nano-crystalline cellulose into epoxy resin via resilin to construct a novel elastic adhesive

Development of high-performance bio-nanocomposite adhesives is of high interest due to their environmentally friendly nature and superior mechanical properties in outdoor environments. Nano-crystalline cellulose (NCC) and resilin are among the most promising bio-nanofillers, providing strength and elasticity, respectively. A novel bio-nanocomposite comprised of NCC and resilin fused to a cellulose binding domain (Res.-CBD) is presented. As a case study, commercial epoxy adhesive was chosen as a matrix for the bio-nanocomposite adhesive. Insertion of hydrophilic NCC into hydrophobic resins, such as epoxy, is typically performed using solvent exchange, chemical modification, emulsifier addition or mixing with water-borne resins, techniques which either limit the material’s application range or which are considered environmentally unfriendly. The unique approach presented here employed Res.-CBD as a surfactant-like agent supportive of the direct insertion of water-suspended NCC into an epoxy resin. The presented approach involves binding of Res.-CBD to NCC through its CBD domain and a chemical reaction between the resin epoxide groups and Res.-CBD amine moieties. The resulting bio-nano material shows a 50 % increase in the Young’s modulus and a 20 % decrease in the tan(δ), compared to pristine epoxy. This novel epoxy adhesive can be advantageous in applications where higher elasticity and Young’s modulus are required.     

Nanocrystalline cellulose/β-casein conjugated nanoparticles prepared by click chemistry

Functionalized nanoparticles are promising building blocks for well-defined nanomaterials with unique properties. Site-specific or regio-selective functionalization of those nanoparticles and organization into high-order assemblies is a major challenge in materials research. Here, we demonstrate site-specific immobilization of a model protein at one tip of nanocrystalline cellulose (NCC), single-crystalline rod-like shaped nanoparticles that are isolated by acid hydrolysis of bulk cellulose. Click reaction between reducing end functionalized NCC bearing azide groups and β-casein micelles bearing acetylene groups results in mushroom-like conjugated nanoparticles in different arrangements. The strategy developed here to design hybrid polysaccharide–protein nanoparticles could be useful for building novel functional self-assembled nanobiomaterials and have potential in nanomedicine, immunoassay and drug delivery applications.     

低维度碳纳米填料诱导聚合物结晶

低维度纳米填料(LDCN)具有优异的物理机械性能.研究发现LDCN与聚合物复合,可显著提高复合材料的力学性能或者增加功能,并且LDCN可诱导多种聚合物结晶.LDCN不仅可作为异相成核剂,提高聚合物的结晶温度和结晶速率,而且可诱导聚合物形成特殊的晶体形貌.研究LDCN对聚合物结晶的影响,进而调控聚合物的结晶度和晶体形态,...     

共轭聚合物在传感器上的应用

由于其特殊的光学和电子性质,共轭聚合物受到人们的广泛关注.共轭聚合物可以在各种传感器件中用作活性材料,例如:生物传感器;气体、湿度传感器;离子传感器;压力、温度传感器等.本文综述了共轭聚合物在传感器应用方面的一些新的进展.     

Synthesis, structure, and optoelectronic properties of phosphafluorene copolymers

Copolymers of phosphafluorenes are obtained through Suzuki copolymerization. The phosphorus-containing copolymers show unique optical, electrochemical, and optoelectronic properties. Blue and white electroluminescence can be observed, depending on the modifications of the phosphorus atoms. It is the first time that conjugated polymers containing phosphafluorene have been prepared and used in PLEDs. Phosphafluorenes are new building blocks for conjugated oligomers and polymers.     

Nano‐Star‐Shaped Polymers for Drug Delivery Applications

With the advancement of polymer engineering, complex star‐shaped polymer architectures can be synthesized with ease, bringing about a host of unique properties and applications. The polymer arms can be functionalized with different chemical groups to fine‐tune the response behavior or be endowed with targeting ligands or stimuli responsive moieties to control its physicochemical behavior and self‐organization in solution. Rheological properties of these solutions can be modulated, which also facilitates the control of the diffusion of the drug from these star‐based nanocarriers. However, these star‐shaped polymers designed for drug delivery are still in a very early stage of development. Due to the sheer diversity of macromolecules that can take on the star architectures and the various combinations of functional groups that can be cross‐linked together, there remain many structure–property relationships which have yet to be fully established. This review aims to provide an introductory perspective on the basic synthetic methods of star‐shaped polymers, the properties which can be controlled by the unique architecture, and also recent advances in drug delivery applications related to these star candidates.