Synthesis and characterization of butyl acrylate graft sodium salt of partially carboxymethylated starch

Graft copolymers were synthesized by graft copolymerization of butyl acrylate (BA) onto sodium salt of partially carboxymethylated starch (Na‐PCMS). Ceric ammonium nitrate (CAN), a redox initiator, was used for initiation of graft copolymerization reaction. All the experiments were run with Na‐PCMS having degree of substitution, DS = 0.35. The grafting reaction was characterized by parameters such as % total conversion (%Ct), % grafting (%G), % grafting efficiency (%GE), and % add‐on. Graft copolymers were characterized by infrared spectral analysis and scanning electron microscopy. Variables affecting graft copolymerization reaction such as nitric acid concentration, reaction time, reaction temperature, and ceric ion concentration were investigated. The results revealed that 0.3M CAN as initiator, 0.3M HNO₃, with reaction time 4–4.5 h at 25–30°C were found as suitable parameters for maximum yield of graft copolymerization reaction. © 2006 Wiley Periodicals, Inc. JAppl Polym Sci 102: 3334–3340, 2006     

面粉中的淀粉组分对面条蒸煮品质的影响

从面粉中提取淀粉、直链淀粉和支链淀粉,按不同的梯度添加到原面粉中制作面条.然后测定面条的蒸煮特性,寻找出淀粉、直链淀粉和支链淀粉对面条蒸煮品质影响的规律.实验表明:随着淀粉添加量的增加,面条的干物质吸水率、干物质损失率、蛋白质损失率都出现了上升的趋势;随着直链淀粉添加量的增加,面条的干物质吸水率出现了下降的趋势,而干物质损失率、蛋白质损失率都出现了上升的趋势;随着支链淀粉添加量的增加,面条的干物质吸水率出现了上升的趋势,而干物质损失率、蛋白质损失率都出现了下降的趋势.     

ST-T接枝淀粉的可生化量分析

通过可生化量即生化需氧量（BOD）与化学需氧量（COD）的比值对一种已在市场中得到应用的接枝淀粉（ST-T）进行生物降解性评价。测定结果表明ST-T的可生化量的平均值是0.340,是PVA的27-85倍,也比酸解淀粉的可生化量值略高,具有十分优异的生物降解性。     

双氧水氧化橡实淀粉的实验研究

以双氧水为氧化剂,Cu2+为催化剂制备橡实氧化淀粉,考察pH值、氧化剂用量、催化剂用量、反应温度及反应时间对橡实氧化淀粉的羰基和羧基质量分数的影响.结果表明,最佳反应条件为:反应温度45℃,反应时间3 h,pH=8,H2O2用量为20%(相对于淀粉干重质量,下同),在此条件下,当催化剂用量为0.052 4%(相对于淀粉干重的质量)时,制得羧基质量分数为0.914 0%的橡实氧化淀粉;在催化剂用量为0.124 4%时,制得羰基质量分数为0.918 3%的橡实氧化淀粉.     

Ozone: An Advanced Oxidation Technology for Starch Modification

ABSTRACT

Ozone processing is one of the encouraging non-thermal and bio-friendly techniques in the food processing sector. The applicability of ozone technology in food industry is increasing due to its antimicrobial action and modification of functional properties of the foods. The structural modifications of starches have major applications in the food and bakery industry for producing products with increased shelf life, improved texture, and retention of moisture content. The positive response of ozonation in carboxyl and carbonyl group alters the viscosity of starch molecules. Rheological characteristics like low viscosity even at an increased concentration, desirable binding properties, and film-forming ability have increased its use in the food processing industry. The influence of ozonation in the physicochemical properties is mainly retrogradation and cross-linking of amylose and amylopectin molecules and enzymatic modifications. Ozonation cause change in crystallinity, viscosity, expansion ratio, and gelatinization temperatures. Finally, ozonation induces many possible changes in native starches for the effective utilization in the processing sectors. In this review, starch modifications utilizing ozone and various research achievements and scientific reports focusing on the effect of ozonation in terms of physical, chemical, and thermal properties of native starches and on the possible modifications have been summarized and discussed. In conclusion, ozone is a green technology that can be effectively used as an alternative oxidation technique for starch modification.     

Rheological behavior of reactive blending of epoxidized natural rubber with cassava starch and epoxidized natural rubber with natural rubber and cassava starch

Epoxidized natural rubbers (ENR‐25 and ENR‐45) were prepared using the performic epoxidation method. Two‐component (ENR–cassava starch) and three‐component (ENR–NR–cassava starch) blends were prepared. ENR‐25 and ENR‐45 were blended with various quantities of gelatinized cassava starch in the latex state. The pure ENR exhibited lower shear stress and shear viscosity than those of the blends with cassava starch. Furthermore, the shear stress and shear viscosity were increased with an increase in the cassava starch concentration. The chemical interaction between the epoxide groups in the ENR and the hydroxyl groups in the cassava starch molecules might be the reason for the increasing trends of the shear stress and shear viscosity. The blends are classified as compatible blends because of the strong chemical bonding between different phases. SEM micrographs were used to clarify the compatibility. Power law behavior with pluglike flow profiles was observed for all sets of ENR–NR–cassava starch blends. Very low power law index values (<0.34) and highly pseudoplastic fluid behavior were also observed. The log additive rule was applied to plots of zero shear viscosity (consistency index) and the shear viscosity versus the concentration of ENR‐25. Positive deviation blending was observed, which indicates compatible blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1752–1762, 2004     

Interfacial adhesion reaction of polyethylene and starch blends using maleated polyethylene reactive compatibilizer

The interfacial reaction of the polyethylene (PE)/starch blend system containing the reactive compatibilizer maleated polyethylene (m‐PE) was directly characterized by Fourier transform infrared (FTIR) spectroscopy. A significant amount of anhydride groups on m‐PE existed as hydrolyzed forms, resulting in a large amount of carboxyl groups. Using a vacuum‐heating‐cell designed in the laboratory, the carboxyl groups were successfully transformed into the dehydrolyzed state (i.e., anhydride group). This result enabled the direct spectroscopic observation of chemical reaction occurring at the interface. For the PE/starch blend system containing m‐PE, the chemical reaction at the interface was verified by the evolution of ester and carboxyl groups in the FTIR spectra. The effect of the reactive compatibilizer on the interfacial morphology was also examined by scanning electron micrography (SEM). Enhanced interfacial adhesion was clearly observed for the blend system containing reactive compatibilizer. Tensile strengths of blend systems containing m‐PE also increased noticeably compared with the corresponding system without compatibilizer. A similar observation was made for the breaking elongation data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 767–776, 2002     

The use of wood pulp and radiation‐modified starch in wastewater treatment

Radiation‐induced graft copolymerization of maize starch/acrylic acid has been performed. Also, natural byproduct wood pulp was used after chemical treatment for the removal of metal ions from the investigated wastewater. The surface and structure morphology of the wood pulp and starch/acrylic acid were investigated by scanning electron microscopy and infrared spectroscopy. The physical parameters, such as swelling, gel percentage, and grafting efficiency (%) of starch/acrylic acid copolymer, were studied. The factors affecting the abilities of the prepared materials for removing heavy metal ions and dyes from aqueous solutions were studied. It was found that the maximum metal uptake is in the following sequence: Fe³⁺ > Cr³⁺ > Pb²⁺ > Cd²⁺. The adsorption capacity of such investigated metal ions increases with the increase of pH values. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Crystallization behavior of starch‐filled polypropylene

Starches of different granule sizes, including corn, rice, and amaranth starches, were used to prepare starch‐filled polypropylene (PP) and the effect of starch granule size on crystallization behavior PP was investigated. Differential scanning calorimetry and scanning electron microscopy were used to monitor the energy changes of the crystallization of the melt and to characterize the morphology of PP/starch composites, respectively. Little interaction was observed between starch and PP despite the difference in starch granule size. The crystallization temperature of PP decreased with the addition of starch and this decrease became more apparent with increasing starch granule size. During nonisothermal crystallization, the dependency of the relative degree of crystallinity on time was described by the Avrami equation. The addition of starch decreased the overall crystallization rate of PP, which was attributed to an increase in the activation energy of crystallization under nonisothermal conditions according to the Kissinger equation. An increase in starch granule size of starch would increase the crystallization activation energy of PP and consequently decrease its crystallization rate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 484–492, 2004     

PCRBSC材料的原位凝固成型制备

依据淀粉颗粒的水中润胀吸水，在加热时产生糊化的特性，实现了一种新的陶瓷原位凝固成型方法。在固相含量接近50％(体积分数)的SiC陶瓷料浆中引入约3％(质量分数)的淀粉，用水溶加热的方法可以原位凝固成型各种形态的SiC陶瓷部件，获得致密、均匀的PCRBSC和RBSC坯体。经真空渗硅，制备出微现结构均匀，性能良好的SiC材料。