非晶颗粒态玉米淀粉的制备与物化性质

以玉米淀粉为原料,采用乙醇溶剂-高温加热法制备非晶颗粒态淀粉.研究了非晶化处理对玉米淀粉的偏光特性、颗粒形貌、结晶性质、流变学性质、溶解度、透明度、凝沉性等物化性质的影响.     

多孔性交联淀粉絮凝剂的制备研究

以玉米淀粉为原料,先用a-耐高温淀粉酶处理,制备多孔玉米淀粉,然后以环氧氯丙烷(ECH)为交联剂,合成具有多孔结构的颗粒态交联淀粉絮凝剂,并对交联工艺进行了初步优化。制备多孔交联淀粉的最佳条件为:25 g多孔淀粉,碱性硫酸钠溶液用量50 mL,环氧氯丙烷用量0.75mL,反应温度25℃,反应时间18 h。     

非晶颗粒态马铃薯淀粉不同条件下的酶降解活性

用光学显微镜分析测试方法,对非晶颗粒态马铃薯淀粉不同条件下酶降解活性进行了观察和研究,结果发现,α 中温淀粉酶对非晶颗粒态淀粉生物活性作用能力高,使用较少量的酶作用于非晶颗粒淀粉,在颗粒表面上可以观察到明显变化。非晶颗粒态淀粉颗粒由于存在爆裂口,所以酶对非晶淀粉作用均从爆裂口开始,逐渐由爆裂口开始均匀扩张,颗粒模糊,最后颗粒消失。不同时间、酶量、温度对酶降解作用均产生一定影响。其中温度可明显加快酶降解速度,酶量的增加同样对酶降解产生显著影响。时间的延长也可以使非晶颗粒态淀粉逐渐降解,但变化较慢。     

玉米淀粉的机械活化效果分析

采用搅拌球磨机对玉米淀粉进行机械活化,分别研究了机械活化对玉米淀粉结晶结构、溶解度、表观粘度、冻融稳定性的影响。结果表明:机械活化使得玉米淀粉颗粒结晶结构受到破坏,结晶程度降低,在3h内使玉米淀粉由多晶态转变成非晶态。同时机械活化对玉米淀粉的理化性质产生显著的影响,糊化温度降低,冷水溶解度提高;淀粉糊的表观粘度下降,并能降低玉米淀粉糊的剪切稀化现象;淀粉分子易于重结晶,析水率增加,冻融稳定性降低。     

非晶颗粒态马铃薯淀粉结构特征

用扫描电子显微镜、偏光显微镜、X -射线衍射法等分析测试方法 ,以原淀粉为参照 ,对非晶颗粒态马铃薯淀粉的颗粒形貌、颗粒大小和结晶程度进行了详尽观察 ,结果发现 ,在非晶化处理过程中发生了从内向外爆裂式膨胀而形成大小、深度、位置不同的爆裂孔 ,并有少量的淀粉颗粒碎片粘附在颗粒的表面上 ,非晶颗粒态淀粉仍然能够保持颗粒外形 ,颗粒大小比原淀粉有所增加 ,不再具有原淀粉颗粒结晶性 ,整个颗粒呈现无定形结构     

交联度对交联羧甲基淀粉性能的影响

以玉米淀粉为原料,以环氧氯丙烷为交联剂,制备交联淀粉(CS),以高、中、低三种交联度的CS为原料,以氯乙酸为醚化剂,制备不同取代度的交联羧甲基淀粉(CCMS),分析其理化性能、吸附性能。结果表明,交联度相同时,随着取代度的增大,CCMS的透明度、溶解度和膨胀力均增大,吸附量提高;取代度相同时,CCMS的透明度、溶解度和膨胀力随着交联度的增加而减小,吸附量呈上升趋势可以改善其再生性能。     

非晶颗粒态马铃薯淀粉微生物降解特性

用光学显微分析测试方法,以原马铃薯淀粉为参照,对非晶颗粒态马铃薯淀粉在微生物作用下的降解过程进行了观察和研究。结果发现,非晶淀粉颗粒松散的无定形结构以及形成的爆裂孔,大大提高了微生物降解反应活性。在微生物作用下,从淀粉颗粒的爆裂孔开始,沿着淀粉颗粒爆裂孔逐步深入,直至最后将淀粉颗粒完全降解,而原淀粉颗粒具有致密的结晶结构,淀粉颗粒表面没有明显的孔洞,因此在同样条件下的生物降解活性,要远远低于非晶颗粒态淀粉。     

丙烯腈接枝交联淀粉的制备及应用研究

以玉米交联淀粉为原料,环氧氯丙烷为交联剂,制备了交联接枝玉米淀粉;再以FeSO4-H2O2为引发剂,研究了丙烯腈接枝交联淀粉的制备工艺及其在处理生活污水方面的应用。结果表明,10g玉米交联淀粉、丙烯腈用量10mL、引发剂用量4mL、接枝时间1.5h、反应温度40℃,此条件下接枝率可达83.7%,接枝效率为116.3%,丙烯腈接枝交联淀粉处理过的污水透光率达96.5%。     

机械活化对玉米淀粉结晶结构与化学反应活性的影响

采用搅拌球磨机对玉米淀粉进行机械活化，用X射线衍射仪、差示扫描量热仪、扫描电子显微镜及粒度分析仪等考察了机械活化对玉米淀粉结晶结构、热特性、颗粒形貌及粒度变化的影响。并将不同活化时间的玉米淀粉在相同条件下与乙酸酐进行酯化反应及与丙烯酰胺进行接枝共聚反应，通过研究机械活化对酯化反应取代度、接枝共聚反应接枝率与接枝效率的影响规律来探讨机械活化对玉米淀粉化学反应活性的影响。结果表明，机械活化预处理能显著提高玉米淀粉酯化反应的取代度及接枝共聚反应的接枝率与接枝效率，说明机械活化能有效地提高玉米淀粉的化学反应活性。其原因是玉米淀粉在机械活化过程中其结晶结构与颗粒形貌均受到破坏，结晶度降低，最终由多晶态转变成非晶态。并随活化时间的延长，糊化温度及糊黏度下降，流动性增强，从而使反应试剂的扩散阻力下降，易于扩散到淀粉分子中参与反应。     

不同交联处理对玉米多孔淀粉颗粒结构的影响

对玉米淀粉进行醚化交联、酯化交联及醚化、酯化复合交联处理,再酶解为多孔淀粉,考察了不同交联处理方法对多孔淀粉的颗粒形貌、结晶结构、粒度分布、比表面积的影响,与多孔淀粉相比,交联处理后玉米多孔淀粉颗粒仍呈蜂窝状中空结构且晶型保持A型结构,但结晶度分别下降2.22%,1.59%,4.02%;平均粒径分别增加12.34%,10.72%,16.17%,粒径分布的均一度提高;比表面积分别减小15.9%,3.22%,25.89%;平均孔径分别增大7.45%,4.47%,24.25%;比孔容分别增大21.92%,36.46%,67.68%。结果表明,经交联后多孔淀粉的颗粒结构发生了明显变化,为多孔淀粉的进一步开发应用提供了参考。     

交联氧化淀粉胶黏剂的制备及性能研究

采用交联氧化法,先用高锰酸钾氧化可溶性淀粉制得低取代度氧化淀粉,再用戊二醛交联成交联氧化淀粉主剂,最后在高温无水条件下加入甲苯二异氰酸酯（TDI）得到氨基甲酸酯交联氧化淀粉胶黏剂。初步探讨了交联氧化机理,分析了交联氧化淀粉胶黏剂的影响因素,利用红Pb（IR）、扫描电镜（SEM）对其进行了表征,对产品的各项性能进行测试研究。结果表明,氧化程度影响其粘结性能,低取代度氧化淀粉粘结性好,且有利于淀粉进一步交联反应,交联提高淀粉耐水性,TDI能够显著提高氧化淀粉的耐水性和粘结强度。当淀粉浓度为10％,高锰酸钾用量为0．0290g,戊二醛用量为2mL,TDI用量为1mL时,制得的交联氧化淀粉胶黏剂的耐水时间为24d。     

Modification of starch–poly(methyl acrylate) graft copolymers by steam jet cooking

Starch-g-poly(methyl acrylate) containing 12.3, 31.9, 51.7, and 58.3% PMA, by weight, were prepared by ceric ammonium nitrate-initiated polymerization of methyl acrylate onto granular cornstarch. The granular structures of these graft copolymers were not disrupted by steam jet cooking at 140°C. At most, only 13% of the polymer was dissolved, and this soluble fraction was comprised largely of starch. The probability of crosslinking within these graft copolymer granules was considered. Physical properties of extruded ribbons depended upon whether or not granular graft copolymers were jet cooked prior to extrusion. Although tensile strengths were not greatly affected by steam jet cooking, cooked samples showed significant increases in both percent elongation and tear resistance. The effects of jet cooking upon the properties of extruded ribbons can be explained by gelatinization of starch within the grafted starch granules. Although jet-cooked granules still remain intact, gelatinization of the starch moiety causes these granules to be less rigid, more deformable, and more easily plasticized by small amounts of water. Loss of starch crystallinity after steam jet cooking was proved by both differential scanning calorimetry and X-ray diffraction. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1021–1029, 1997     

淀粉基聚乙烯醇完全生物降解塑料薄膜的结构与性能

通过优化工艺条件，制备了高淀粉填充量的淀粉／聚乙烯醇完全生物降解塑料薄膜，研究了提高淀粉用量对淀粉／聚乙烯醇（PVA）完全生物降解塑料薄膜的力学性能和耐水性影响；并分析了耐水改性助剂尿素用量对薄膜的吸水率和生物降解性能的影响。结果表明，通过先糊化、后共混、再交联的薄膜制备工艺过程，能够获得高淀粉填充量的淀粉／聚乙烯醇完全生物降解塑料薄膜；先糊化打破了淀粉颗粒的原有形态结构，促进了淀粉与聚乙烯醇的共混相容性，从而获得了优良的力学性能；耐水改性助剂尿素的使用，能够大幅度地降低材料的吸水率，同时提高材料的生物降解性和环境友好程度。     

Biodegradable and functionally superior starch–polyester nanocomposites from reactive extrusion

Biodegradable starch‐polyester polymer composites are useful in many applications ranging from numerous packaging end‐uses to tissue engineering. However the amount of starch that can form composites with polyesters without significant property deterioration is typically less than 25% because of thermodynamic immiscibility between the two polymers. We have developed a reactive extrusion process in which high amounts of starch (approx. 40 wt%) can be blended with a biodegradable polyester (polycaprolactone, PCL) resulting in tough nanocomposite blends with elongational properties approaching that of 100% PCL. We hypothesize that starch was oxidized and then crosslinked with PCL in the presence of an oxidizing/crosslinking agent and modified montmorillonite (MMT) organoclay, thus compatibilizing the two polymers. Starch, PCL, plasticizer, MMT organoclay, oxidizing/crosslinking agent and catalysts were extruded in a co‐rotating twin‐screw extruder and injection molded at 120° C. Elongational properties of reactively extruded starch‐PCL nanocomposite blends approached that of 100% PCL at 3 and 6 wt% organoclay. Strength and modulus remained the same as starch‐PCL composites prepared from simple physical mixing without any crosslinking. X‐ray diffraction results showed mainly intercalated flocculated behavior of clay at 1,3,6, and 9wt% organoclay. Scanning electron microscopy (SEM) showed that there was improved starch‐PCL interfacial adhesion in reactively extruded blends with crosslinking than in starch‐PCL composites without crosslinking. Dynamic mechanical analysis showed changes in primary α‐transition temperatures for both the starch and PCL fractions, reflecting crosslinking changes in the nanocomposite blends at different organoclay contents. Also starch‐polytetramethylene adipate‐co‐terephthalate (PAT) blends prepared by the above reactive extrusion process showed the same trend of elongational properties approaching that of 100% PAT. The reactive extrusion concept can be extended to other starch‐PCL like polymer blends with polymers like polyvinyl alcohol on one side and polybutylene succinate, polyhydroxy butyrate‐valerate and polylactic acid on the other to create cheap, novel and compatible biodegradable polymer blends with increased toughness. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1072–1082, 2005     

油田用延时性高黏凝胶制备方法研究

基于改性淀粉凝胶于调剖堵水、封堵、钻完井等方面优异的使用性能及应用前景。以淀粉、丙烯酰胺(AM)为原料,偶氮二异丁腈(AIBN)为引发剂,利用淀粉同烯类单体进行接枝共聚,通过交联剂来实现共价键交联,在实验室条件下合成一种适用于中、高温油藏,成胶时间延时至2 h内可控的高强度的改性淀粉凝胶。研究了引发剂的用量、交联剂的用量、反应温度、p H值对胶体成胶性能(体系黏度和成胶时间)的影响。结果表明:在引发剂质量分数介于0.04%~0.06%,交联剂质量分数在5.1%左右,反应温度为80℃,体系p H为10时所制得的聚合物胶体性能最佳,其体系黏度对应为1 950×103 m Pa·s。     

乳液交联法制备多孔淀粉及其吸附性能

以可溶性淀粉为原料,用环己烷为油相的油包水乳液,通过交联反应成功制备了多孔淀粉。通过实验,优化了环己烷的加入量。扫描电镜显示多孔淀粉的表面有大量微孔;红外光谱扫描表明交联成功,并且大量羟基仍然存在;X射线衍射光谱分析结晶度大大降低。多孔淀粉的比表面积为3.456m2/g,吸油率高达162%,对亚甲基蓝的最大饱和吸附量是145mg/g;相比酶解法制备的多孔淀粉,本文提出的乳液交联法制备的多孔淀粉的比表面积提高了1.6倍,吸油率提高了0.7倍,对亚甲基蓝的最大饱和吸附量提高了近4倍。多孔淀粉通过氢键作用吸附染料亚甲基蓝和碱性品红,且是一个快速平衡的过程。