交联辛烯基琥珀酸淀粉酯亲核取代机理与结构表征

以木薯淀粉为原料,环氧氯丙烷和辛烯基琥珀酸酐为变性剂,选用水相法工艺制备交联辛烯基琥珀酸淀粉酯。采用红外光谱、电镜扫描、X射线衍射和差示扫描量热等手段对产物进行结构分析和合成机理研究。结果表明:在pH为7.0～8.5的范围内,产物取代度随着pH值的增大而增大,说明交联酯化符合亲核取代反应机理;红外光谱图中,1718.72cm-1和1570.33cm-1处产生了新的吸收峰,证实在淀粉中引入了辛烯基琥珀酸基团,930.97cm-1处吸收峰强度加强,说明淀粉分子间形成了醚化交联键;淀粉经交联酯化双重变性后受侵蚀的颗粒增多,部分颗粒表面变粗糙,并出现凹陷;交联酯化反应主要发生在淀粉颗粒的非结晶区,对结晶区破坏不明显;交联酯化提高了淀粉的糊化温度和热稳定性。结构分析证明了交联辛烯基琥珀酸淀粉酯兼具交联与酯化双重结构特征,有望能广泛应用于食品及医药行业中。     

高取代度酯化淀粉的制备与工艺研究

采用有机溶剂法制备高取代度淀粉琥珀酸酯。以琥珀酸酐为酯化剂,对淀粉进行酯化改性。经单因素试验法得到淀粉琥珀酸酯的制备条件,采用正交试验法研究淀粉琥珀酸酯制备的最佳工艺条件：反应温度50℃,反应时间5 h,每克活化淀粉催化剂用量1 m L,活化淀粉与酸酐分子的摩尔比为1∶3。在最佳制备条件下,制得取代度为0.40的淀粉琥珀酸酯。     

非晶交联辛烯基琥珀酸淀粉酯的制备与结构表征

以木薯淀粉为原料,三偏磷酸钠(STMP)和辛烯基琥珀酸酐(OSA)为变性剂,用乙醇溶剂法合成非晶交联辛烯基琥珀酸淀粉酯(N-COSAS)。以结合磷含量(CP)、取代度(DS)、黏度(η)为评价指标,探讨STMP用量(占淀粉干基的质量分数),交联时间、交联温度、交联p H值和酯化时间、酯化温度、酯化p H值等因素对CP或DS和η的影响。通过单因素和正交试验,得出制备低黏度N-COSAS的较佳工艺条件:在加入STMP 1.5%时,交联反应的时间、温度和p H值分别为4 h,45℃和10.0,酯化反应的时间、温度和p H值分别为3 h、35℃和8.5。扫描电镜观察显示N-COSAS颗粒表面有明显裂痕,表面被卷起;X射线衍射图谱显示,N-COSAS的相对结晶度为8.24%,晶型属于V型;红外光谱显示,N-COSAS在1570.06 cm–1处出现新的吸收峰,在929.69 cm–1处峰的强度增加,证明在淀粉分子中引入了辛烯基琥珀酸基团和交联键。     

低取代度碎米淀粉辛烯基琥珀酸酯的工艺分析

碎米淀粉与辛烯基琥珀酸酐酯化生成辛烯基琥珀酸淀粉酯,其是典型的慢消化淀粉,低取代度时可任意比例加入食品。试验分析反应时间、pH、温度、淀粉浓度及辛烯基琥珀酸酐加入量对酯化淀粉取代度的影响;从单因素及工业生产考虑,分别在反应时间3 h、pH 8. 5、反应温度35℃、淀粉乳浓度35%及辛烯基琥珀酸酐用量2%时,酯化取代度较为合适。     

交联酯化作用对木薯淀粉表面活性的影响

以木薯淀粉（NS）为原料,环氧氯丙烷为交联剂,辛烯基琥珀酸酐为酯化剂,利用湿法工艺合成了交联淀粉（CS）、辛烯基琥珀酸淀粉酯（OSAS）及交联辛烯基琥珀酸淀粉酯（COSAS）,并用实验方法测定了NS、CS、OSAS和COSAS的基本表面活性：对钙离子的容忍度,临界溶解温度（Krafft点）,起泡性和泡沫稳定性,对植物油脂和矿物油的乳化活性。结果表明：这4种淀粉对钙离子容忍度次序为：N4种淀粉㈣点均在70℃左右：4种淀粉起泡性及泡沫稳定性顺序为：OSAS〉COSAS〉NS〉CS：4种淀粉乳化性能大小顺序为oSAS〉COSAS〉CS〉NS。     

离子液体介质中OSAS的制备与表征及乳化性质分析

以玉米淀粉（CS）为原料,辛烯基琥珀酸酐（OSA）为酯化剂,在无催化剂条件下,在1-烯丙基-3-甲基氯化咪唑离子液体（AMIMCl）介质中,通过均相酯化反应制备辛烯基琥珀酸淀粉酯（OSAS）。利用红外光谱（FTIR）、X射线衍射（XRD）、扫描电镜（SEM）、热重-红外联用仪（TGA-FTIR）、凝胶渗透色谱（GPC）和偏光显微镜（POM）对产物结构、热特性、相对分子质量及乳化性质进行分析。结果表明,制备OSAS的较佳工艺条件为：时间2h,温度90℃,淀粉质量分数6%,OSA与淀粉脱水葡萄糖单元（AGU）摩尔比可根据所需产品的取代度在0.03～0.24范围内选取。FTIR分析表明,CS已成功发生了酯化反应;XRD与SEM证明所得OSAS为无定形形态的细小颗粒聚结物;TGA-FTIR测试表明,在氮气环境中,OSAS中所接入的辛烯基琥珀酸酯基团能稳定至200℃;GPC与POM证明AMIMCl介质中制备的OSAS是优良的大分子乳化剂。     

机械活化对木薯淀粉醋酸酯化反应的强化作用

采用搅拌球磨机对木薯淀粉进行机械活化,以不同活化时间的木薯淀粉为原料,以醋酸酐为酯化试剂、甲磺酸为催化剂制备淀粉醋酸酯,并以取代度为评价指标,分别研究了机械活化时间、反应时间、反应温度、催化剂用量及醋酸酐用量对木薯淀粉醋酸酯化反应的影响. 结果表明,机械活化对木薯淀粉酯化反应有显著的强化作用,活化时间越长,取代度越高. 主要原因是机械活化使木薯淀粉紧密的颗粒表面和结晶结构受到破坏,降低了结晶度,酯化试剂更容易渗透到颗粒内部使淀粉醋酸酯化. 其他因素对淀粉酯化反应的影响规律受活化时间的制约,活化时间越长,酯化反应对反应温度、催化剂及醋酸酐浓度的依赖性越低. 并利用红外光谱对木薯淀粉、活化淀粉及高取代度淀粉醋酸酯的结构进行了表征.     

非晶交联辛烯基琥珀酸淀粉酯的一步法合成及其性能

以非晶木薯淀粉(N-NS)为原料,三偏磷酸钠(STMP)和辛烯基琥珀酸酐(OSA)为变性剂,采用一步法合成非晶交联辛烯基琥珀酸淀粉酯(N-1-COSAS),测定产物的取代度、结合磷含量、透明度、表观黏度、特性黏度和蓝值,并与三步法合成的非晶交联辛烯基琥珀酸淀粉酯(N-3-COSAS)作对比。同时采用傅里叶红外光谱仪(FT-IR)、扫描电镜(SEM)、X射线衍射仪(XRD)和差示扫描量热仪(DSC)对产物的官能团、形貌、结晶结构和热稳定性进行表征。结果表明,N-1-COSAS的取代度、结合磷含量、特性黏度要比N-3-COSAS的大,糊化温度比N-3-COSAS的低;N-1-COSAS与N-3-COSAS在1600 cm–1附近都出现了辛烯基C=C特征吸收峰,表明酯化反应的发生;N-1-COSAS与N-3-COSAS的结晶度均比原淀粉低,峰的弥散程度与N-NS相似;N-1-COSAS与N-3-COSAS颗粒表面比N-NS更加粗糙,且这二者的热稳定性优于N-NS。     

辛烯基琥珀酸淀粉酯研究现状

辛烯基琥珀酸淀粉酯是淀粉经辛烯基琥珀酸酯化改性后得到的一类酯化淀粉,具有亲水亲油的优良品质,常被用作乳化剂、增稠剂、微胶囊壁材等,应用前景广阔,近年来受到人们的广泛关注。因此,本文对辛烯基琥珀酸淀粉酯的反应机理、理化性质、研究现状等进行综述,以期为辛烯基琥珀酸淀粉酯的进一步研究提供参考。     

疏水改性籽粒苋淀粉颗粒稳定的Pickering乳液

利用碱提法从籽粒苋种子中提取了籽粒苋淀粉(St)颗粒,使用辛烯基琥珀酸酐(OSA)对提取的淀粉颗粒进行疏水改性,得到了两亲性的辛烯基琥珀酸淀粉酯(OSA starch)颗粒。通过红外光谱(FTIR)及X射线衍射仪(XRD)对其结构进行了表征。随着改性淀粉颗粒取代度的增加,其疏水性增强。以液体石蜡作为油相,将改性淀粉颗粒作为单一的乳化剂应用于Pickering乳液的制备。当油水体积比为1∶1时,取代度为0.089的改性淀粉颗粒的质量分数为0.5%以上,即可得到优异稳定性的乳液。随着改性淀粉颗粒用量的增加,乳液液滴粒径变小,乳液稳定性增强。     

Kinetic study of the nonthermal effect of the esterification of octenyl succinic anhydride modified starch treated by microwave radiation

With cassava starch as a raw material and octenyl succinic anhydride as an esterifying agent, octenyl succinic anhydride modified starch (OSA–starch) was prepared in an aqueous medium and treated by water‐bath heating and microwave radiation at a certain temperature, respectively. The reaction kinetics of esterification were studied. The structural analysis and synthesis mechanism of OSA–starch were investigated by means of scanning electron microscopy and Fourier transform infrared spectroscopy. The differences in the esterification reaction kinetics between starches treated with water‐bath heating and microwave radiation were observed. Under the condition of water‐bath heating, the apparent activation energy of the esterification reaction was 52.22 ± 1.21 kJ/mol, and the pre‐exponential factor was 9018.20/min^?1. Under the condition of microwave radiation, the apparent activation energy of the esterification reaction was 50.13 ± 1.16 kJ/mol, and the pre‐exponential factor was 4510.21/min^?1. We found that microwave radiation could reduce both the activation energy of the reaction and the pre‐exponential factor. The lowering effect of the apparent activation energy was greater than that of the pre‐exponential factor under the condition of microwave radiation, and this resulted in increased reaction rates. The change in the esterification reaction kinetics was a nonthermal effect of microwave radiation on the esterification of cassava starch. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43909.     

环己烷辅助超临界CO2流体制备淀粉酯

利用环己烷等助剂辅助超临界CO₂流体制备辛烯基琥珀酸淀粉酯,研究助剂辅助效果,优化超临界酯化反应条件,并采用NMR、SEM和XRD等进行结构表征。结果表明：环己烷有助于改善超临界CO₂对酯化剂的溶解性能,酯化反应效率约为无助剂时的3.0倍;反应温度、压力、时间及酯化剂用量等对反应也有重要影响,当温度90℃、压力12 MPa、酯化剂用量2%、时间3 h时,反应效率高达83%以上;酯化剂用量为4%时,取代度为0.0191,反应效率可达61%。结构表征发现淀粉分子中引入了酯化基团,产品依然保持淀粉颗粒特征和A型结晶结构,但颗粒表面遭到局部破坏,结晶度降低。以上结果说明,环己烷提高了超临界淀粉酯化反应效率,改善了酯化反应条件。     

Effect of surface esterification with octenyl succinic anhydride on hydrophilicity of corn starch films

Surface of corn starch films was modified through esterification using octenyl succinic anhydride as reactant. Physical properties of the films, moisture absorption, and water contact angle were measured to characterize the effect of the surface esterification modification. The influences of the concentration of alkaline aqueous solution for activating starch, reaction temperature, and time were investigated. It was found that the pretreatments with 1.0% or 2.0% NaOH aqueous solution and reacting at 35°C for 6 h gave rise to films possessing higher water contact angle, lower equilibrium moisture content, and moisture absorption rate at 95% relative humidity (RH). After the surface esterification modification, the equilibrium moisture content of the starch film decreased up to 29% at 95% RH and the surface water contact angle of the film increased up to 83%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Modified tapioca starch as a rheology modifier in acrylic dispersion system

Tapioca starch was modified by esterification reaction using octenylsuccinic anhydride (OSA) to use as a rheological modifier. Effect of degree of substitution (DS = 0.01–0.04) of octenyl side chain on rheological properties of modified starch in acrylic dispersion system (ASD) was investigated. At low starch to dry acrylic ratio (0.2:100), shear viscosity at low shear rate of OSA-starch containing ASD system increased when the DS of OSA-starch increased. Thickening ability and thixotropic behavior of modified starches in acrylic dispersion system were studied at various modified starches to dry acrylic ratios (0.1–4:100). The results showed that modified starches provided good thickening efficiency. Moreover, an optimum concentration of modified starches, giving the highest thickening efficiency decreased as the DS increased. Results of rheological behavior illustrated that associative networks were formed by hydrophobic interaction between octenyl side chains and acrylic particles in acrylic dispersion system. The rheological properties of modified starches prepared in this study showed a potential in using as an associative thickener in water-based coating system.     

氧化-酯化-MMA接枝复合变性木薯淀粉的合成与表征

以木薯淀粉为主要原料,经双氧水氧化、邻苯二甲酸酐酯化,再与甲基丙烯酸甲酯进行接枝合成出复合变性淀粉。实验得到较佳的反应条件为:氧化反应时间为2h,温度为40℃,氧化剂用量为5mL,酯化反应时间为4.5h,温度为45℃,催化剂用量为4%;接枝反应的接枝时间为4.0h,温度为40℃,投料比(MMA∶酯化淀粉)为1.75∶1,引发剂浓度为0.05mol/L。用红外光谱(FTIR)、扫描电镜(SEM)对原料和复合变性薯淀粉的结构进行了表征。