微波辐射制备淀粉接枝共聚高吸水树脂研究进展？

综述了微波辐射下五种淀粉接枝共聚高吸水树脂的制备研究进展,包括淀粉接枝丙烯腈类高吸水树脂、淀粉接枝丙烯酸类高吸水树脂、淀粉接枝多元单体类高吸水树脂、淀粉系列互穿网络高吸水树脂、无机复合淀粉接枝高吸水树脂等;指出了微波辐射制备淀粉接枝共聚高吸水树脂的研究中,几个需要加强的研究方向：加强理论研究与实践研究的相互促进,开发新型无机矿物复合淀粉接枝共聚高吸水树脂等。     

改性淀粉在环境和生化工程中的应用

介绍了改性淀粉在环境工程和生物工程中的研究和应用,重点评述了酯化淀粉、醚化淀粉、接枝共聚淀粉、复合淀粉絮凝剂、淀粉微球等改性淀粉的应用研究进展,对今后的研究方向提出了一些建议。     

淀粉接枝共聚高吸水性树脂的研究进展

分别以化学引发法和辐射引发法阐述了淀粉接枝高吸水树脂的研究进展和生产情况。介绍了化学引发接枝聚合淀粉接枝丙烯腈类树脂、淀粉接枝丙烯酸类树脂、淀粉接枝多元单体类树脂、复合型淀粉接枝脂类树脂的研究现状,对化学引发的主要影响因素进行了评述。讨论了辐射引发淀粉接枝高吸水树脂中所应用的微波辐射引发、紫外光辐射引发和γ射线辐射引发的技术优势和应用现状。指出今后淀粉类高吸水性树脂的研究应该向多元接枝共聚、制备复合型树脂和抗盐性树脂、微波固相合成、简单工艺、高效引发剂和加强理论基础研究方向发展。     

淀粉基絮凝剂在染料废水处理中的应用进展

本文简要概述了淀粉基絮凝剂在染料废水处理中的应用研究现状,其中重点概述了阳离子化改性淀粉絮凝剂、两性淀粉絮凝剂和接枝共聚淀粉絮凝剂的研发情况及应用进展。     

淀粉接枝共聚改性研究进展

淀粉接枝共聚物是一类新型功能性材料,具有天然高分子材料和合成高分子材料的双重性能,近年来得到了研究者的广泛重视。从淀粉的预处理方法、复合引发剂和多元单体的应用、聚合过程动力学模型及反相乳液聚合方法应用等方面综述了淀粉接枝共聚改性的研究进展。展望了接枝淀粉的研究方向。     

淀粉反相乳液法三元接枝共聚改性研究与表征

以丙烯酰胺(AM)和丙烯酸(AA)为接枝单体,采用反相乳液聚合技术对木薯淀粉进行接枝共聚改性,生成淀粉-丙烯酰胺-丙烯酸三元接枝共聚物(St-g-AM/AA)。考察反应温度和时间、引发剂和单体浓度、单体配比等因素对淀粉三元接枝共聚反应过程的影响规律,并通过红外光谱等表征共聚物结构。实验结果显示:引发剂浓度、单体浓度和单体比、反应温度和时间等因素对三元接枝共聚改性反应影响显著;红外光谱和电镜扫描表征证明接枝共聚反应发生在淀粉颗粒表面,经三元接枝共聚反应淀粉已被AM和AA成功改性。     

淀粉接枝改性的研究进展

综述了淀粉接枝共聚改性的原理和工艺条件，着重评述了接枝淀粉在高分子降解材料、纺织上浆材料、造纸工业及水处理工业絮凝剂等方面应用的新进展，并对该领域的研究前景作了展望。     

绿色淀粉絮凝剂在废水处理中应用进展

淀粉絮凝剂具有绿色、无毒、价廉、易于生物降解等优点,称之为绿色絮凝剂。文章综述了阳离子改性淀粉絮凝剂、阴离子改性絮凝剂、两性絮凝剂以及交联、接枝共聚絮凝剂在废水处理方面的应用,并对今后淀粉絮凝剂的研究提出了展望。     

研究丙烯腈与淀粉在微波加热时的接枝共聚反应

通过微波加热,研究了以硝酸铈铵为引发剂,淀粉与丙烯腈的接枝共聚反应,探讨了引发剂浓度、单体浓度、反应时间和微波功率对接枝共聚的影响。     

淀粉接枝共聚物制备及应用研究综述

淀粉与乙烯基单体接枝共聚是淀粉改性的重要方法。淀粉接枝共聚物具有合成与天然高分子的优良性能,如塑化成膜性、超强吸水性、絮凝性、粘合性等。它在高吸水材料、生物降解塑料、造纸工业添加剂、环境废水处理等领域有着广泛的应用。综述了淀粉接枝共聚物的制备及应用研究,并从工业化的角度对科研开发工作提出了几点建议。     

高锰酸钾引发双水相中淀粉接枝丙烯酰胺共聚反应

在双水相中进行淀粉接枝丙烯酰胺共聚反应是一种新的聚合方法,对以聚乙二醇为分散介质、高锰酸钾为引发剂的双水相中淀粉接枝丙烯酰胺共聚反应进行了研究,考察了引发时间、引发剂浓度及配比对产品单体转化率、接枝率和接枝效率的影响。通过实验得到聚合反应的最佳工艺条件:引发时间为10 min,n(高锰酸钾)∶n(丙烯酰胺)=3.0×10-4∶1,n(高锰酸钾)∶n(H+)=1∶10,反应温度为50℃,反应时间7 h,此时得到的产品的单体转化率C为98.88%,接枝率G为144.53%,接枝效率GE为97.81%。最后通过红外光谱仪进行结构表征。     

纳米纤维素晶须表面接枝及其液晶性能研究进展

作为一种新兴的纳米生物材料,纳米纤维素日益受到各界的广泛关注,对其进行表面接枝改性并开发新的功能是十分必要的。本文综述了纳米纤维素晶须表面接枝的技术及研究进展,主要介绍了传统自由基聚合、离子和开环聚合及活性自由基聚合技术,包括氮氧自由基调控活性聚合、原子转移自由基聚合、可逆加成-断裂链转移聚合、单电子转移活性自由基聚合,讨论了各种接枝聚合方法的适用范围和优缺点。简述了点击化学在纳米纤维素晶须表面接枝的应用。通过各种聚合方法改性得到的纳米纤维素晶须接枝共聚物往往具有一些特殊的功能,某些接枝共聚物在适当的溶剂中可以形成液晶态,本文重点介绍了接枝改性的纳米纤维素晶须的液晶性能及其形成机理和影响因素等。     

化学引发合成玉米淀粉接枝共聚物的一种新方法

研究了以 ( NH4) 2 Ce( NO3 ) 6及 ( NH4) 2 S2 O8为引发剂条件下 ,玉米淀粉与丙烯酰胺在纯水溶剂中接枝共聚制备吸水性功能高分子材料的新方法。并从接枝共聚单体选择、淀粉预处理等六个方面讨论了影响接枝共聚物吸水速度的因素。通过对玉米淀粉和接枝共聚物红外光谱的解析 ,提出了一种新的反应机理     

淀粉絮凝剂的研究概况

对淀粉絮凝剂的接枝方法、共聚类型、引发剂的种类做了较为详细的叙述.在接枝方法部分主要讨论了化学法、辐射法及双螺杆挤出法等;在共聚类型部分主要讨论了淀粉与一元至四元乙烯基单体的共聚反应:在引发剂的种类部分主要讨论了化学引发和辐射引发等.另外,对如何做好淀粉絮凝剂提出了3点看法,尤其强调将开发研制与实际应用结合起来,进行技术转化.     

淀粉接枝丙烯酸聚合型絮凝剂的合成及絮凝性能研究

以可溶性淀粉为主要原料,以丙烯酸为接枝单体,硝酸铈铵和过硫酸钾为复合引发剂,采用溶液聚合的方法对糊化处理后的淀粉进行接枝聚合,合成出环保型淀粉衍生物水处理絮凝剂。通过对接枝聚合反应温度、反应时间、引发剂用量以及丙烯酸单体用量等因素对接枝率影响的研究,确定较佳的接枝产物合成条件：淀粉10g,单体丙烯酸用量10mL,硝酸铈铵和过硫酸钾（摩尔比1：1）复合引发体系用量2mmol,接枝反应温度50℃,接枝反应时间3h,接枝率达到43．2％。利用选煤后的废水对其产品絮凝性能进行实验研究,确定较佳的废水絮凝处理条件。     

Swelling and rheology of saponified starch–g–polyacrylonitrile copolymers. Effect of starch granule pretreatment and grafted chain length

A series of well-characterized starch–g–polyacrylonitrile (PAN) graft copolymers was prepared from corn starch which had been heated in water at temperatures up to 94°C to vary the extent of starch granule swelling and disruption. Graft polymerization onto gelatinized starch gave less frequent grafting of higher molecular weight PAN than comparable graft polymerizations onto ungelatinized starch. A graft copolymer was also prepared from gelatinized starch under high dilution conditions to give lower molecular weight grafted PAN and more frequent grafting. Graft copolymers were then saponified with sodium hydroxide to convert nitrile substituents to a mixture of carboxamide and sodium carboxylate. Saponified graft copolymers were only partially water soluble and consisted largely of highly swollen, insoluble gel, which was separated from solubles for the study of physical properties. Saponification mixtures were also dried to yield highly absorbent polymer films. With the exception of the graft copolymer prepared under high dilution conditions, the physical properties of saponified graft copolymers depended on whether or not the granules of starch were gelatinized before graft polymerization. Compared with saponified graft copolymers derived from ungelatinized starch, those prepared from gelatinized starch gave films that absorbed larger amounts of aqueous fluids. Also, the gel fractions from these saponified gelatinized polymers exhibited higher water swelling, lower shear modulus, and a lower reduced viscosity function (η/cQ). The saponified graft copolymer prepared from gelatinized starch under high dilution conditions more closely resembled those prepared from ungelatinized starch, suggesting that molecular weight of grafted PAN and the grafting frequency rather than starch granule pretreatment might be the most important factor which influences properties.     

超临界二氧化碳中丙烯酸乙酯/3-氯丙烯接枝天然橡胶的合成与表征

采用超临界二氧化碳溶胀聚合法,以丙烯酸乙酯（EA）/3-氯丙烯（AC）为单体对天然橡胶进行了接枝改性,合成了接枝共聚物NR-g-(EA/AC)。考察了压力和引发剂用量对接枝聚合反应的影响;对NR-g-( EA/AC)进行了红外光谱、力学性能、耐溶剂性、耐燃性、硬度的测试及接枝效率和接枝率的计算,并与溶液聚合法所得NR-g-( EA/AC)的性能进行了比较。结果发现,在接枝橡胶中成功的引入了—C=O和—Cl基团;接枝橡胶的弹性模量、拉伸强度、硬度、耐燃性和耐溶剂性较天然橡胶的有了显著提高。使用溶液法和超临界二氧化碳溶胀聚合法改性天然胶乳都获得了较高的转化率和接枝率,所得产品的机械力学性能相近,但溶液法所得产品的耐溶剂性能优于后一种方法。由于超临界二氧化碳的绿色溶剂性质,超临界二氧化碳溶胀聚合法有望取代溶液聚合法而发展成一种绿色的接枝改性天然橡胶方法。     

Kinetics and mechanism of free radical grafting of methyl acrylate onto sago starch

The graft copolymerization was carried out by methyl acrylate with sago starch in which ceric ammonium nitrate was used as an initiator. It has been found that the rates of graft polymerization and grafting efficiency were dependent upon the concentration of ceric ammonium nitrate (CAN), methyl acrylate (MA), sago starch (AGU, anhydro glucose unit), mineral acid (H₂SO₄), and as well as reaction temperature and period. A rate equation of polymerization was established from the proposed reaction mechanism, and the rate of polymerization (R_p) was the first‐order dependence of the MA monomer concentration and square root of the CAN concentration. A new kinetic model of the grafting reaction has been proposed, and a normal kinetics of methyl acrylate polymerization was observed. An equation of a predicted model relating the graft fraction of poly(methyl acrylate) with the sago starch has been derived, and validity of the predicted model was verified by the experimental results. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 784–791, 2000     

Chemical modification of starch by reactive extrusion

Processes for chemical transformation of starch by extrusion processing (reactive extrusion, REX) are reviewed with a focus on non-food applications. The scope, advantages, limitations and specificity of various REX processes for are examined in this context. The processes covered include: the grafting of monomers from starch as single units, such as ring-opening of epoxides, esterification (with lactones, anhydrides, acids, halides or vinyl esters) phosphorylation and silylation; graft polymerization from starch by radical-induced grafting or the ring-opening polymerization of lactones; reactive compatibilization with polyesters and polyolefins by grafting to or from starch; crosslinking of starch with epichlorohydrin or by phosphorylation; and the degradation of starch thermally or catalyzed by acid or enzymes.