焦磷酸络锰三价离子引发淀粉-丙烯酰胺的接枝共聚合

将带有极性基团的乙烯类单体通过化学接枝到淀粉或纤维素之类的天然多糖上,可作为絮凝剂、脱除剂和粘接剂^[1～3],近来已发展为高吸水性材料和石油分离剂^[4]。用Ce⁴⁺引发乙烯类单体接枝到淀粉和纤维素类已有报道^[5]。Rayonier用Mn³⁺的焦磷酸盐络合物引发接枝乙烯类单体至纤维素及其衍生物上^[6];Cenita等用Mn³⁺引发MMA、AN接枝淀粉^[7]。本文以焦磷酸络锰离子(Mn³⁺)作引发剂、丙烯酰胺(AM)为单体、淀粉为接枝基体进行接枝共聚,这一工作目前在国内外尚未见报道。     

Studies on Mechanical Properties of Full-Biodegradable Starch-PVA-Polyester Films

A kind of full-biodegradable film material is discussed in this article.The film material is composed of starch,PVA,degradable polyesters(PHB,PHB-V,PCL) with built plasticizer,a cross-linking reinforcing agent and a wet strengthening agent.It contains a high percentage of starch.costs cheap and is excellent in weather fastness,temperature resistance and waterproof and it could be completely biodegraded.The present paper deals minly with a new technical route using a new type of electromagnetic dynamic blow molding extruder and some effects on mechanical properties of the system.     

红外光谱法研究交联淀粉的退化行为

用红外光谱研究了交联淀粉的退化过程, 结果表明, 交联淀粉具有与原淀粉大分子类似的退化过程, 即淀粉大分子临近的链段间形成双螺旋局部有序化结构, 再进一步规则地排列成结晶有序的结构. 由于交联键的限制, 交联淀粉的有序化过程相对较慢、 程度较低, 而且当交联度过高时无法形成结晶结构.     

交联淀粉囊材对含羧基类除草剂的缓释性能研究

以淀粉或变性淀粉为囊材,对囊化农药进行控释或缓释,可延长药效、避免药害、减少浪费和防止污染^[1-4]。 然而,水溶胀程度大导致淀粉胶囊制品耐水性差。目前,降低其水溶胀程度的措施有淀粉黄原酸酯化后的交联囊化法^[5]、淀粉－钙加合物法^[6]和淀粉－硼酸络合物法^[7,8]。但由于含羧基类农药的水溶性对碱敏感,上述方法中淀粉的糊化、化学改性和交联所必须的强碱性条件会使含羰基类农药呈现水溶性,致使它们在水环境条件下会以更大的速度从淀粉囊材中释放出来。可 见,含羧基类农药不能用这几种方法来改善其缓释性能。本文以甲醛为交联剂,在淀粉囊化农药过程中对淀粉囊材进行交联,能够有效地降低淀粉胶囊制品的水溶胀程度的和所囊药剂的释放速度,延长有效控释时间,较大幅度地提高其缓释性能和耐水性。该囊化方法解决了一些碱敏感性农药在淀粉中的囊化问题。     

PREPARATION OF STARCH SUCCINATE WITH INTERMEDIATE DS BY AQUEOUS SLURRY REACTION

The succinylation of cornstarch by slurry reaction has been studied using sodium hydroxide as catalyst.Several reaction parameters affecting the succinylation were investigated including the concentration of starch in water,the ratio of succinic anhydride to starch,the reaction time and the reaction temperature,The favorable conditions for an intermediate degree of substitution(DS) and reasonably high reaction efficiency(RE) are pH 8.5-9.0,50% starch by weight to water.succinic anhydride to starch 1/1(w/w),reaction time 4h,reaction temperature 30℃ .Under these conditions,the DS of 0.45 and RE of 28% were achieved.The addition of an adequate amount of crosslinking agent imparted starch succinate water absorbency.     

高吸水性树脂的合成与应用

综述了高吸水性树脂的研究、发展状况。并指出了高吸水性树脂研究中存在的问题。     

CuO NPs@Starch as a novel chemotherapeutic drug for the treatment of several types of gastrointestinal system cancers including gastric,pancreatic, and colon cancers

Copper oxide nanoparticles were successfully synthesized through a simple and ‘green’ route using starch as a capping and stabilizing agent under ultrasonic irradiation in alkaline medium. Unique reaction condition was prepared by ultrasonic irradiation, releasing the stored energy in the collapsed bubbles and heats the bubble contents that leads to Cu(II) reduction in the presence of starch. The obtained nanoparticle (CuO NPs@Starch) was characterized by advanced physical and chemical techniques like Transmission Electron Microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), Uv–Vis spectroscopy, scanning electron microscopy (SEM), X-ray Diffraction (XRD) and energy-dispersive X-ray analysis (EDX). The properties of CuO NPs@Starch against gastric cancer (AGS and KATO III), pancreatic cancer (AsPC-1 and MIA PaCa-2), and colon cancer (HCT 116 and HCT-8) were evaluated. The viability of malignant cancer cell lines reduced dose-dependently in the presence of CuO NPs@Starch. After clinical study, CuO NPs@Starch can be utilized as an efficient drug in the treatment of gastric, pancreatic, and colon cancers in humans.     

Effect of ultrasound on structural and physicochemical properties of sweetpotato and wheat flours

Ultrasound technologies are increasingly used for modification of physicochemical properties of food systems. Effects of ultrasound (20 kHz, 750 W) up to 20 h on physicochemical properties of two varieties of sweetpotato flour were studied and compared with those of commercial wheat flour. Ultrasound induced structural modifications on starch granules mainly in the morphological changes of granules and reduction of the crystallinity. Longer treatment significantly decreased enthalpy change of gelatinization, pasting viscosities, gelling capacity, while increasing in vitro starch digestibility of raw flour. Besides, prolonged treatment reduced total phenolic contents and in vitro antioxidant activities of sweetpotato flours, mainly due to pyrolysis and release of hydroxyl radicals caused by cavitation. The extents of these changes were seen to depend on the treatment time and indicated degradation and modifications of the chemical components (e.g., starch and polyphenol) of flours. This study suggests that ultrasound processing as a non-thermal and energy-saving technique has potential to modify flour functionalities.     

Barrier property enhancement of starch citrate bioplastic film by an ammonium-thiourea complex modification

Although citric acid modification of starch biopolymers gives a more thermodynamically stable starch citrate, the barrier properties of the product is relatively poor. This paper reports a novel modification process which significantly improved the barrier properties of starch citrate by treating it with a complex formed from ammonium acetate and thiourea in the presence of a polysorbate catalyst. The barrier characteristics which were investigated include percentage moisture absorption, percentage reflectance, and water vapour release study. FTIR, SEM and TGA were employed to characterize the starch citrate biofilms before and after ammonium-thiourea complex modifications.     

2-(p -toluidino)-6-naphthalene sulfonate as a fluorescent probe for flocculation studies of cationic potato amylopectin and nanosized silica particles. 2. Flocculation by binding of nanosized silica particles

2-(p-toluidino)-6-naphthalene sulfonate (TNS) is a probe that fluoresces strongly when bound to certain proteins and polymers, but weakly in aqueous solutions. The reversible association of TNS is used to monitor the binding of anionic nanosized silica particles (NSP) to cationic potato amylopectin starch (CApS) through the decreasing fluorescence emission as TNS is competitively released by the particle binding. Steady-state fluorescence measurements at different mixing ratios of CApS and NSP provide data on the equilibrium binding. The isotherm derived is used to establish the fact that the most efficient flocculation between CApS and NSP occurs when the polymer coils are nearly saturated by NSP, but still have positively charged parts left. This supports a patch-flocculation mechanism. Stopped-flow experiments show that NSP binding to CApS occurs within a few milli seconds. This observation allows turbidity changes which occur on longer timescales to be ascribed to particle-decorated polymers undergoing changes in the conformation or aggregation. Received: 14 August 1998 Accepted in revised form: 4 December 1998