废弃天然高分子基功能材料

从废弃高分子角度对废弃生物质的高附加值再利用进行综述,阐述了废弃生物质中天然高分子的类型以及废弃生物质中包含的大量天然高分子具有官能团丰富、可降解、生物相容、无毒无害等优异的性能,归纳了废弃生物质的传统处理方法及作为材料使用的再利用途径,介绍了废弃天然高分子用作复合材料、吸附材料、载体材料、能源材料、医用高分子材料、智能高分子材料等的研究进展,并对废弃天然高分子的资源化利用进行了展望。     

基于天然高分子的导电材料制备及其在柔性传感器件中的应用

天然高分子材料具有来源广泛、化学成分多样、生物相容性和生物降解性良好等优势,是一类绿色可持续再生资源.近年来,基于天然高分子的绿色柔性传感器件研究受到了国内外学者的广泛关注,并取得了长足的进展.本文以天然高分子导电材料为主线,总结了基于天然高分子制备导电材料的模板法和掺杂法.模板法直接以天然高分子材料的天然骨架结构作为基质,而掺杂法以天然高分子材料处理后的产物或衍生物作为基质.归纳了基于天然高分子的柔性导电材料在湿度、温度、应变、气流/气体、光、生物传感器件中应用的研究进展,最后展望了基于天然高分子的柔性导电材料在设计和组装柔性传感器方面的前景,为高效发展绿色柔性电子和天然高分子材料的高值化利用提供新思路.     

药物微胶囊壁材研究进展

药物微胶囊在药物的缓控释放等方面有着广阔的应用前景,因而近年来正成为农药、医药新剂型领域研究的热点之一。开发有竞争力的微胶囊壁材是当前药物微胶囊研究领域的一个重要课题。本文从天然高分子材料、全合成高分子材料、半合成高分子材料及无机材料4个方面综述了药物微胶囊壁材研究与应用的最新进展,着重阐述了明胶-阿拉伯胶、壳聚糖-海藻酸钠、环糊精及其衍生物、聚乳酸及其共聚物、脂肪族聚碳酸酯等生物可降解高分子材料作为药物微胶囊壁材的研究进展。     

天然高分子细胞培养基质的研究进展

天然高分子材料如壳聚糖、丝素蛋白和胶原蛋白等具有异体抗原性弱、生物相容性好、可生物降解且能促进细胞粘附、生长和增殖等优点。同人工合成高分子材料相比,天然高分子几乎不含有机溶剂和引发剂等物质,生物安全性高,是细胞培养基质的首选原材料。近年来,随着生物科技的发展,其新功能也不断被发现并受到学术界的广泛重视。本文综述了天然多糖类和天然蛋白质类高分子材料的理化性质及在细胞培养基质领域中的应用,对目前所存在的一些问题进行了描述并预测其发展动向。     

高分子物理学系统讲演

1.高分子性貭的特点 人类使用高分子物貭的历史已經很久,例如蚕絲早在古代就开始使用,然而对它的物理性质和化学性貭却很少研究。近几十年来,高分子的应用迅速增长并遍及許多方面。现在所使用的高分子,在天然产物中,除蚕絲外,尚有棉花、麻、羊毛、橡胶、皮革、胶等,也有从人工合成制得的材料,如人造纤維、人造皮革、人造橡胶等可以用来代替天然产物,此外高分子物貭的溶液还可以用来做油漆、胶等。仅从上面所列举的材料而言,高分子物貭的重要性已是不必多說的了,何况組成动物組織单元的蛋白貭也是高分子,因此高分子不仅与化学与工业有关,而且     

木质素活化改性制备酚醛树脂胶黏剂研究进展

木质素由于化学结构与苯酚相似,通过活化改性可部分替代苯酚制备木质素改性酚醛树脂胶黏剂。既可降低成本、达到生物质资源高效利用的目的,并且制备的木质素改性酚醛树脂胶黏剂有毒残余较低,具有环保意义,是合成制备生物质高分子材料的重要途径。本文综述了国内外研究人员在木质素活化改性制备酚醛树脂胶黏剂研究领域的最新进展,重点介绍了化学改性、物理改性、生物改性等木质素活化改性方法,比较了不同改性产物制备酚醛树脂胶黏剂的性能,并对影响木质素活化改性制备酚醛树脂胶黏剂实现工业化应用的主要因素进行了分析。     

米根霉细胞壁结构性多糖与丙烯酸接枝共聚反应研究

化学改性天然高分子絮凝剂是利用天然高分子物质进行化学改性而成的。与人工合成的有机高分子絮凝剂相比,它具有选择性大、无毒、价廉、易降解等优点,因此将会有广阔的应用前景,近几年,将乙烯基单体接枝到生物高分子上的工作引起了人们的兴趣,这种天然高分子与合成高分子的结合有可能得到理想的性能,获得新的材料：如生物降解塑料、絮凝剂、离子交换剂等,目前这方面的研究主要中在纤维素、淀粉和壳聚糖的接枝共聚上。     

玉米醇溶蛋白高分子材料的制备与应用进展

作为一种天然高分子,玉米醇溶蛋白(Zein)具有疏水性、可降解性、抗菌性等特点。本文在介绍Zein结构、组成及性质的基础上,首先介绍了Zein的提取与脱色方法;然后,总结了通过小分子与高分子改性制备Zein基高分子材料的方法;最后,综述了基于Zein的高分子材料在食品、生物医药、纤维、粘合剂以及其他行业的应用研究进展。作为一类生物相容与生物可降解的天然高分子材料,Zein基材料在药物载体、食品包装、粘合剂等领域将具有更广泛的发展前景。     

基于玉米醇溶蛋白高分子材料的制备与应用进展

作为一种天然高分子,玉米醇溶蛋白(Zein)具有疏水性、可降解性、抗菌性等特点。本文在介绍Zein结构、组成及性质的基础上,首先介绍了Zein的提取与脱色方法;然后,总结了通过小分子与高分子改性制备Zein基高分子材料的方法;最后,综述了基于Zein的高分子材料在食品、生物医药、纤维、粘合剂以及其他行业的应用研究进展。作为一类生物相容与生物可降解的天然高分子材料,Zein基材料在药物载体、食品包装、粘合剂等领域将具有更广泛的发展前景。     

高分子载体材料对青霉素酰化酶的固定化作用

介绍了天然高分子材料和合成高分子材料对青霉素酰化酶的固定化作用,着重讨论了高分子材料的制备、性质及其表面修饰对固定化酶活性和使用稳定性的影响。     

Mixed Polymer‐Coated Magnetic Nanoparticles as Forward Osmosis Draw Agents of Tuned Hydrophilicity

We recently reported a polymer‐coated magnetic nanoparticle (MNP) draw agent for the forward osmosis (FO) water desalination process. The water flux was found to increase when the polymer poly(sodium acrylate) (PSA) was anchored to the MNP surface as compared to the polymer (or polyelectrolyte solution) alone, due to the polymer chains being stretched out and most of the hydrophilic groups on the polymer contributing to water flux. We herein report the use of a secondary polymer poly(N‐isopropylacrylamide) PNIPAM to manipulate the PSA polymer conformation and influence inter‐ and intrachain interactions to enhance the efficiency of the FO draw agent. These PSA–PNIPAM‐coated MNPs generated a much higher water flux of ～11.66 LMH when compared to the 100 % PSA‐coated MNPs featuring a value of ～5.32 LMH under identical FO conditions. The osmotic pressure and water flux driven by the mixed polymer‐coated MNPs were found to be a strong function of the net polymer coverage on MNPs, that is, net available hydrophilic groups. Our new draw agent demonstrates potential for use in the water industry due to its improved efficiency and cost effectiveness as it uses only ～0.062 % (w/v) of the draw agent solution.     

Antiseptic Nanocapsule Formation via Controlling Polymer Deposition onto Water-in-Oil Miniemulsion Droplets

The stable nanodroplet was prepared by inverse miniemulsion with an aqueous antiseptic solution dispersed in an organic medium of solvent/nonsolvent mixture containing an oil-soluble surfactant and the polymer for shell formation. The change in gradient of the solvent/nonsolvent mixture, obtained by heating at 50 °C, led to the precipitation of the polymer in the organic phase and deposition onto the large interphase of the aqueous miniemulsion droplets. The monodisperse polymer nanocapsule, with the size range of 80–240 nm, dispersed in cyclohexane phase was achieved as a function of surfactant concentration. By variation of polymer content, molecular weight and type, an encapsulation efficiency of 20–100% was obtained as detected by proton-nuclear magnetic resonance spectroscopy measurement. The nanocapsule could be easily transferred into water as continuous phase resulting in aqueous dispersion with nanocapsule containing the antiseptic agent as an aqueous core. The encapsulated amount of the antiseptic agent was evaluated to indicate the durability of the nanocapsule's wall. Additionally, the different types of polymer having glass transition temperature ranging from −60 to 100°C have been successfully used. Currently, the research work on the incorporation of nanocapsules onto natural rubber (NR) latex in order to prepare NR latex glove containing the antiseptic agent nanocapsules is carried out. By using the simple and versatile layer-by-layer (LbL) technique based mainly on an electrostatic interaction between oppositely charged species, the deposition of nanocapsules onto NR latex film has successfully been fulfilled.     

The influence of non-rubber constituents on performance of silica reinforced natural rubber compounds

An in-rubber study of the interaction of silica with proteins present in natural rubber show that the latter compete with the silane coupling agent during the silanisation reaction; the presence of proteins makes the silane less efficient for improving dispersion and filler–polymer coupling, and thus influences the final properties of the rubber negatively. Furthermore, the protein content influences the rheological properties as well as filler–filler and filler–polymer interactions. Stress strain properties also vary with protein content, as do dynamic properties. With high amounts of proteins present in natural rubber, the interactions between proteins and silica are able to disrupt the silica–silica network and improve silica dispersion. High amounts of proteins reduce the thermal sensitivity of the filler–polymer network formation. The effect of proteins is most pronounced when no silane is used, but they are not able to replace a coupling agent.     

双亲性光敏感遥爪聚合物C-PNIPAAm的合成与性能

以7-羟基-4-甲基香豆素为原料,依次与环氧氯丙烷、二硫化钠反应得一含香豆素基元的二硫化物(C-S-S-C),并以其与三丁基膦复合体系为链转移剂,偶氮二异丁腈(AIBN)为引发剂,N-异丙基丙烯酰胺(NIPAAm)为单体制备了末端为香豆素光响应基元的双亲性遥爪聚合物(C-PNIPAAm).用傅里叶变换红外(FT-IR)光谱、凝胶渗透色谱(GPC)、氢核磁共振(1H-NMR)等对该聚合物进行了结构表征.研究显示该双亲性遥爪聚合物可在水中直接形成胶束,并以荧光素为疏水性客体考察了聚合物胶束的光控释放行为.在波长大于310 nm的紫外光照射下,聚合物链末端的香豆素单元可进行光二聚,胶束结构随之改变,因而所负载的荧光素可得到逐步有效释放.动态激光光散射(DLS)检测显示,光二聚反应使聚合物胶束平均粒径从56.6 nm增大至101.0 nm.     

Swelling and Reswelling Characteristics of Cross-Linked Poly(vinyl alcohol)/Chitosan Hydrogel Film

Poly(vinyl alcohol) (PVA), hydrogel was prepared by using glutaraldehyde as a cross-linking agent. The blend semi-synthetic hydrogel film, consisting of PVA and chitosan, was prepared from a solvent-casting technique and characterized for their intermolecular interactions using infrared method. The swelling and reswelling behaviors, as well as mechanical properties of the synthetic and semi-synthetic gels were examined by weighing and tensile testing, respectively. Cross-linking the two types of polymer with glutaraldehyde produces a film with lower crystallinity and smaller swelling and reswelling degrees, but having improved mechanical properties. Also, the two types of films show a pH-dependent swelling characteristic. It was found that, the reswelling properties of synthetic hydrogels can be improved by blending PVA with certain ratio of natural polymer. This blending film, can be improve sandy soil properties for cultivation, such as, controlled release of water.     

Natural superabsorbent plastic materials based on a functionalized soy protein

A natural superabsorbent polymer (SAP) material based on an acylated soy protein was studied as a green alternative to non-biodegradable SAP. In order to obtain the natural SAPs, different amounts of succinic anhydride were used as acylating agent. Once the functionalized protein was obtained, it was mixed thoroughly with glycerol and then molded through a lab-scale injection molding device. Water uptake of samples obtained reached values much higher than those based on unacylated protein. Moreover, a greater extent of the acylation reaction led to higher water uptake values for the corresponding SAPs, probably related to their higher hydrophilic character. Water imbibing capacity measurements and thermogravimetrical analysis (TGA) seemed to confirm this. The presence of larger porous regions in acylated samples observed in SEM images could also play a role in their higher water uptake values.Furthermore, an increase in the extent of acylation reaction led to plastics with lower Young's modulus and higher extensibility.     

Studies on addition polymerization in mixed solvent system. Part I. Chain transfer of water in polymerization of methyl methacrylate

The role of water as a chain-transfer agent in addition polymerization of methyl methacrylate and acrylamide in a mixed solvent system was studied. Water does not have any transfer with the growing polymer radical. The degree of polymerization is found to increase with increasing water concentration. This is probably due to a reduced termination rate resulting from coiling of the polymer chain in the presence of a nonsolvent like water.     

Water‐compatible halloysite‐imprinted polymer by Pickering emulsion polymerization for the selective recognition of herbicides

A water‐compatible molecularly imprinted polymer was prepared by Pickering emulsion polymerization using halloysite nanotubes as stabilized solid particles. During polymerization, we used 4‐vinylpyridine as monomer, divinylbenzene as cross‐linking agent, toluene as porogen, 2,2‐azobisisobutyronitrile as initiator, 2,4‐dichlorophenoxyacetic acid as template to form the oil phase, and Triton X‐100 aqueous solution to form the water phase. The halloysite nanotubes molecularly imprinted polymer was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Kinetic and equilibrium bindings were also employed to evaluate the adsorption properties of the imprinted polymer. The imprinted polymer showed better selectivity, more rapid kinetic binding (60 min) for 2,4‐dichlorophenoxyacetic acid in pure water compared with rebinding in toluene. The imprinted polymer was used as a sorbent to enrich and separate 2,4‐dichlorophenoxyacetic acid from water, and was detected by high‐performance liquid chromatography with UV detection.     

Effect of a new hydrophobically modified polyampholyte on the formation of inverse microemulsions and the preparation of gold nanoparticles

A new regular polyampholyte, namely poly-(N,N-dially-N,N-dimethylammonium-alt-N-octyl-maleamic carboxylate), was synthesized by alternating free radical copolymerization. The influence of the added polymer on the range of the inverse micellar region (L(2) phase) of a SDS-based system was investigated. The phase behavior as well as conductivity measurements indicate that the polymer, which forms hydrophobic microdomains, is located more in the water core of the microemulsion droplets rather than at the interface of the surfactant film. The polyampholyte proved to be an efficient reducing and stabilizing agent for the formation of gold colloids. The process of nanoparticle formation was investigated in the absence of any other reducing agent, in water as well as in the microemulsion template phase. In both cases, nanoscalic gold particles can be synthesized, while the adsorption of the polymer on the particle surface prevents their aggregation due to electrosteric stabilization.     

Preparation of a novel molecularly imprinted polymer using a water-soluble crosslinking agent

A molecularly imprinted polymer was prepared using a water-soluble crosslinking agent. An ionic complex was utilized as the assembly for the template molecule and the functional monomer, and water as porogenic solvent during preparation of the imprinted polymer. The results of chromatographic evaluations for the prepared polymer suggested that the polymer had much lower hydrophobicity compared with usual octadecyl group bonded silica or the usual molecular imprinted polymer prepared from ethyleneglycol dimethacrylate, and the selective recognition ability for template molecule in the completely aqueous condition.