利用Ostwald熟化作用合成空心碳纳米材料

以淀粉等易获得的生物质为碳前驱物, 亚铁盐为添加剂, 采用水热法制备了碳材料. 实验发现, 在反应过程中, 首先生成了被无定形碳包裹的铁氧化物纳米棒, 形成碳/铁氧化物的核/壳结构. 在进一步的反应中, 铁氧化物核自发溶解, 最终得到了空心的碳纳米棒. 讨论了铁氧化物自发溶解的原因, 认为空心碳纳米棒的形成是由Ostwald熟化现象造成的. 当以葡萄糖或环糊精为碳前驱物时, 得到的是空心碳球, 这可能与各种碳前驱物不同的表面活性剂作用有关.     

Interfacial phenomena in starch/fumed silica at varied hydration levels

Hydrated powders of non-gelatinised starch and hydrogels of gelatinised starch alone or with addition of modified nanosilica (with grafted aminopropylmethylsilyl groups substituting one-third of surface silanols) were studied using broadband dielectric relaxation spectroscopy (DRS), thermally stimulated depolarisation current (TSDC) method and ¹H NMR spectroscopy with layer-by-layer freezing-out of bulk and interfacial waters. The ¹H NMR and TSDC techniques with the use of Gibbs–Thomson relation for the freezing point depression allow us to calculate: (i) the thermodynamic parameters of interfacial water weakly and strongly bound to polymer molecules and nanoparticles; (ii) size distributions of pores filled by structured water; (iii) surface area and volume of micro-, meso- and macropores. The DRS and TSDC results for hydrogels and hydrated powders with starch/modified fumed silica show that the β- and γ-relaxations of starch are strongly affected by water and functionalised silica nanoparticles which slow down both low- and high-frequency and low- and high-temperature relaxations.     

离子液体增塑改性玉米淀粉/聚丁二酸丁二醇酯共混材料的结构与性能

为考察离子液体对淀粉/聚丁二酸丁二醇酯(PBS)的作用效果,降低淀粉/PBS的脆性,以离子液体(1-丁基-3-甲基咪唑氯盐[BMIM]Cl)作为增塑改性剂通过熔融共混法制备了玉米淀粉/聚丁二酸丁二醇酯(PBS)共混材料,采用红外光谱(FTIR)、扫描电镜(SEM)、热重分析(TGA)、X射线衍射分析(XRD)及力学性能测试方法研究了[BMIM]Cl对淀粉/PBS共混材料结构和性能的影响.结果表明,[BMIM]Cl能与淀粉/PBS分子发生强相互作用,破坏淀粉/PBS共混物中原有的氢键与结晶结构,增强界面相互作用,改善相容性,进而改变淀粉/PBS共混材料的结构与性能;[BMIM]Cl的加入不影响淀粉/PBS的热稳定性,可使材料玻璃化转变温度(Tg)、结晶温度(Tc)、冷结晶温度(Tcc)及结晶度(Xc)降低.[BMIM]Cl具有显著降低淀粉/PBS脆性的作用,使其断裂伸长率大幅度增加,拉伸强度和弹性模量降低.     

Mechanical and anti-pathogenic characterization of starch-based materials

Food products are susceptible to the growth of pathogenic microbes, such as Escherichia coli. Smart packaging is an effective non-invasive route to reducing food pathogens. Some lactic acid bacteria such as Lactobacillus plantarum inhibit the growth of pathogens. We report here the incorporation of L. plantarum within a starch matrix using sucrose as a protectant and glycerol as a plasticizer. The anti-pathogenic and mechanical characteristics of the films produced were tested. The properties of the films varied depending on their composition, with tensile strengths ranging from 6.8 – 8.7 MPa and maximum tensile stress relaxation from 4 – 13%. Antimicrobial activity (agar disk diffusion) assays showed that films incorporating L. plantarum inhibited E. coli moderately, and when assisted with starch-degrading α-amylase, E. coli growth was reduced significantly. These findings demonstrate the potential of this natural anti-pathogenic film to be applied as an edible coating for food and as a second layer with traditional synthetic thermoplastics to improve food shelf-life.     

淀粉基聚合物胶束用作药物载体

两亲性聚合物能通过亲疏水作用自组装为核-壳结构,而这独特的优势已使其成为在肿瘤靶向药物缓释方面具有很好发展前景的药物载体.淀粉原材料来源丰富,价格低廉,同时具有良好的生物相容性和生物可降解性,故基于淀粉的两亲性聚合物胶束正引起越来越多研究者极大的关注.作为药物载体,淀粉基聚合物胶束不仅可以提高药物的水溶性、延长药物在体内的循环时间、降低副作用和通过增强渗透与滞留(EPR)效应提高药物在靶向部位的优先累积,还可以在淀粉骨架上引入一些刺激响应型的官能团实现胶束快速靶向释药的功能.因此,淀粉基聚合物胶束在用作药物载体方面有着广阔的发展潜力.本文结合本课题组目前的研究工作和近几年的相关报道对淀粉基聚合物胶束作为药物载体的最新研究进展做简要综述.     

Effect of a natural polyphenolic extract on the properties of a biodegradable starch-based polymer

A polyphenol-containing extract from winery bio-waste (EP) has been used as an additive for a starch-based polymer (Mater-Bi). EP was used to tailor Mater-Bi properties, thus avoiding the use of synthetic polymer additives. It was found that EP was able to efficiently modulate the processing, mechanical, thermal and biodegradation properties. The observed decrease in melt viscosity showed that EP could improve productivity in polymer processing. Owing to the plasticizing activity of the additive, larger values of elongation at break were found. Moreover, the Mater-Bi crosslinking, which occurs upon thermal aging, was delayed in the presence of EP. Finally, the bio-disintegration rate of doped Mater-Bi decreased, thus suggesting that EP acted as an antimicrobial agent by interfering with the bio-digestion of the polymer films.     

Physical and degradation properties of binary or ternary blends composed of poly (lactic acid), thermoplastic starch and GMA grafted POE

Binary and ternary blends composed of poly (lactic acid) (PLA), thermoplastic starch (TPS) and glycidyl methacrylate grafted poly (ethylene octane) (GPOE) were prepared using Haake Mixer. The mechanical morphology, thermal properties, water absorption, and degradation properties of the blends were also investigated. The elongation at break and impact strength of the ternary blends were greatly increased by the filling of GPOE. Compared to non-GPOE binary blends, the morphology of ternary blends with GPOE indicated that starch granules melted and there was good compatibility between PLA matrix and TPS. The mechanism and schematic diagram of the reactions in PLA, TPS, and GPOE were proposed and proved by testing and observing the morphology. Moreover, the biodegradation and thermal decomposition were studied through compost testing and thermal gravimetric analysis, respectively. Biodegradation results indicated that the blends have the excellent biodegrade ability.     

THERMAL CHARACTERIZATIONS OF WOOD FLOUR/STARCH CELLULOSE ACETATE COMPOUNDS

Thermogravity analysis (TGA) and differential scanning calorimetric (DSC) analysis, as well as dynamic thermal analysis (DMA), were carried out to study the interfacial interaction between wood flour (WF) and starch/cellulose acetate (SCA) blend. It was found that the main components in the compounds, namely, starch, cellulose, and cellulose acetate, started to decompose at around 330°C, a characteristic temperature for breaking glycoside-linked glucose units. Complexation of lignin in WF with amylose in SCA occurred during compounding, which gave rise to new crystallites that have a melting point of around 160°C. Hydrogen bonding is believed to play a key role in the crystallization. With increasing WF content, both the glass transition temperature and softening temperature increase as a result of the restricted molecular chain mobility imposed by rigid cellulose filaments. In addition, the DMA data revealed that amylose can occur as linkages in the crystallites. All these observations indicated that the interfacial adhesion between SCA and WF is relatively strong, even in absence of a coupling agent.     

微波灰化-氢化物发生-原子荧光光谱法测定出口小麦淀粉中痕量铅

建立了微波灰化,断续流动-氢化物发生-双道原子荧光光度计测定小麦淀粉中痕量铅的方法,解决了小麦淀粉前处理难的问题,研究了加入硝酸后对铅测定的影响,探讨了酸度、还原剂浓度、基体效应对氢化物发生的影响。铅的线性范围为1.00-200.0μg/L,方法检出限为0.57μg/L,回收率为88.50%-103.3%,精密度为2.54%-4.82%。     

蒽酮比色法测定马铃薯淀粉深加工工艺废液总糖含量的研究

研究了葡萄糖、果糖、蔗糖、马铃薯淀粉标准液、马铃薯粉渣和马铃薯淀粉深加工工艺废液,确定了蒽酮比色法测定马铃薯淀粉深加工废液总糖含量的最佳实验条件。在马铃薯淀粉深加工废液中加入盐酸,在105℃消煮120min,用活性碳脱色,过滤,滤液加入蒽酮,沸水浴中加热12min,显色体系在620nm处的吸光度达到最佳值,糖的浓度在1—100μg/mL范围内符合比耳定律,线性相关系数为0.9997。用所拟方法对凉山洲盐源世富农业科技公司马铃薯淀粉深加工工艺废液总糖进行测定,相对误差在5%以内,加标回收率在96.42%—103.16%之间,结果满意。