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。     

纳米载体两亲性接枝共聚物及其在农药中的应用

两亲性接枝共聚物是纳米胶囊的主要组成部分, 在药物领域得到了广泛的关注。本文综述了两亲性接枝共聚物的研究现状, 重点阐述了两亲性接枝共聚物的制备、性质及其应用, 展望了两亲性接枝共聚物在农药领域中的应用前景。     

乙烯-乙酸乙烯酯共聚物接枝聚合物的合成、表征及应用新进展

乙烯-乙酸乙烯酯共聚物(EVA)以其优异的耐低温性、耐氧化性、耐环境应力开裂性和耐腐蚀性等性能,在很多领域得到了广泛应用。近年来,为了赋予其新的性能和功能,拓展其应用领域,对EVA的接枝改性及其应用研究受到广泛关注。文章首先介绍了利用熔融接枝法、溶液接枝法以及乳液接枝法合成EVA接枝聚合物的研究新进展,接着以EVA接枝马来酸酐聚合物为例分析了接枝反应机理,然后对EVA接枝聚合物的表征方法包括仪器法和化学滴定法及应用进行总结和评述。最后对EVA接枝聚合物的合成方法的优缺点、表征方法及其应用的发展前景进行了阐述,指出溶液接枝法是未来的发展趋势,共混相容剂、膜材料和原油降凝材料是其未来比较广泛的应用领域。     

用淀粉接枝聚醚共聚物合成高回弹性聚氨酯泡沫塑料

淀粉在交联剂、催化剂等作用下与聚醚接枝合成接枝共聚物。该接枝共聚物可用于制备高回弹性聚氨酯泡沫塑料(HRPU)。它能有效地提高HRPU泡沫塑料的承载能力和舒适性。通过对其合成工艺及性能的研究,找到了合成高回弹聚氨酯泡沫塑料的较佳工艺配方。其各项性能指标优于美国ASTM标准。     

ATRP法接枝卤胺分子制备纤维素共聚物抗菌材料

以氯化1-烯丙基-3-甲基咪唑（[AMIM]Cl）离子液体为溶剂,采用原子转移自由基聚合法（ATRP）在微晶纤维素上接枝功能单体N-羟甲基丙烯酰胺,制备了卤胺化合物中间体,应用卤化法将接枝共聚物中的N-H转化为N-Cl键获得具有抗菌性的共聚物材料,并对其抗菌性能进行研究。通过FT-IR、¹H NMR、SEM以及抗菌测试等分析手段表征分析了聚合物的结构、表面形貌和抗菌性能等。结果表明该工艺合成了纤维素接枝N-羟甲基丙烯酰胺共聚物,接枝后表面明显变得粗糙,有利于材料与细菌的接触进而充分发挥其抗菌性能,制备的材料对金黄色葡萄球菌和大肠杆菌均表现出良好抗菌性能,在抗菌材料领域具有较好的应用前景。     

功能化聚烯烃接枝共聚物的制备和应用研究新进展

介绍了制备功能化聚烯烃接枝共聚物的意义及近年来功能化聚烯烃接枝共聚物的设计与合成中的应用研究新进展,重点评述了制备功能化聚烯烃接枝共聚物时所采用的3种方法,I偶合接枝法;II引发接枝法:1阴离子聚合;2硼氧自由基存在下的控制自由基聚合;3原子转移自由基聚合(ATRP);4氮氧自由基存在下的控制自由基聚合(NMRP);5可逆加成-裂解链转移活性自由基聚合(RAFT);III直接接枝法,并对上述方法进行了简单的优缺点对比。随后介绍了功能化聚烯烃接枝共聚物的应用。最后对功能化聚烯烃接枝共聚物的未来发展趋势进行了展望,认为对新型、高效、实用的制备方法的探索以及实际应用将是功能化聚烯烃接枝共聚物领域的主要研究方向。     

MMA和BA接枝淀粉的制备

以硝酸铈铵与过硫酸钾为引发剂,甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为接枝单体,制备MMA和BA接枝淀粉的共聚物。研究了不同配比的淀粉与MMA,BA对接枝率及接枝效率的影响。利用傅里叶变换红外光谱、核磁共振氢谱、X射线衍射、热重分析对所制接枝共聚物进行表征。随着淀粉配比提高,共聚物接枝率降低,产率及接枝效率不断提高。MMA和BA接枝淀粉共聚物的耐化学溶剂性和热稳定性良好,在N2保护下,起始降解温度超过252.9℃,800℃的质量保持率为24.38%。接枝共聚物的拉伸性能良好。     

ATRP法接枝卤胺分子制备纤维素共聚物抗菌材料

以氯化1-烯丙基-3-甲基咪唑([AMIM]Cl)离子液体为溶剂,采用原子转移自由基聚合法(ATRP)在微晶纤维素上接枝功能单体N-羟甲基丙烯酰胺,制备了卤胺化合物中间体,应用卤化法将接枝共聚物中的N—H转化为N—Cl键获得具有抗菌性的共聚物材料,并对其抗菌性能进行研究。通过FT-IR、1H NMR、SEM以及抗菌测试等分析手段表征分析了聚合物的结构、表面形貌和抗菌性能等。结果表明该工艺合成了纤维素接枝N-羟甲基丙烯酰胺共聚物,接枝后表面明显变得粗糙,有利于材料与细菌的接触进而充分发挥其抗菌性能,制备的材料对金黄色葡萄球菌和大肠杆菌均表现出良好抗菌性能,在抗菌材料领域具有较好的应用前景。     

木钠接枝丙烯酸添加剂在水煤浆制备中的应用

通过木质素磺酸钠与丙烯酸的接枝共聚实验和该接枝共聚物在水煤浆中的应用研究 ,对其在水煤浆中的作用机理进行的初步探讨表明 ,木质素磺酸钠接枝丙烯酸后具有分散和稳定的双重效果。     

羧甲基甲壳素接枝甲基丙烯酸甲酯的制备及成膜性

通过高速搅拌,未使用乳化剂,制备了羧甲基甲壳素和甲基丙烯酸甲酯的接枝共聚物,避免了产物中引入乳化剂杂质。利用红外光谱对接枝共聚物进行了表征。考察了不同接枝率的产物在12种常见溶剂中的溶解性,结果表明,不同接枝率的接枝共聚物都有良好的水溶性,可以形成无色透明的膜,扩大了其实际应用价值。     

Physical properties of model graft copolymers and their use as blend compatibilizers

The present investigation pertains to the structure–property relationships of highly structured graft copolymers. The specific model graft copolymers are based on an elastomeric backbone, i.e., poly(ethyl acrylate), and monodisperse thermoplastic grafts, i.e., polystyrene. The synthesis of these graft copolymers is based on the free-radical polymerization of ethyl acrylate and an anionically polymerized polystyrene macromonomer. It is clearly demonstrated that grafts significantly enhance tensile properties. The level of improvement is directly related to the graft level, i.e., number of grafts/chain, and graft molecular weight. In addition, blending these graft copolymers into their respective homopolymer mixture results in a mechanical performance strikingly dependent on the molecular characteristics of the graft copolymer. For example, tensile strength is maximized at a level between one and two grafts per chain. This result parallels observations noted in blend compatibilization using diblock and triblock copolymers. It is also demonstrated that using mutually grafted copolymers produces an interesting variety of compatibilized ternary (or higher) component blends. © 1994 John Wiley & Sons, Inc.     

壳聚糖接枝共聚物的应用研究

以壳聚糖与甲基丙烯酸接枝共聚物为载体,采用直接压片法制得药物非诺落芬钙的缓释片剂.测定了缓释片剂中的非诺落芬钙的体外溶出速率,用红外光谱(FT-IR)表征了缓释片剂中非诺落芬钙与接枝共聚物形成的分子间氢键.     

Turbulent drag effectiveness and shear stability of xanthan-gum-based graft copolymers

A number of graft copolymers of xanthan gum and polyacrylamide have been synthesized by grafting acrylamide onto xanthan gum using the ceric-ion-initiated solution polymerization technique. The effects of various synthesis parameters such as amount of catalyst, reaction time, and ratio of xanthan and acrylamide on drag reduction effectiveness of the graft copolymers have been studied. The scaling up of grafting reaction has been accomplished in 40-L reactor. The drag reduction effectiveness of the graft copolymers is investigated over a wide range of concentrations and Reynolds numbers. It is shown that the maximum drag reduction obtainable in xanthan gum solutions above 300 ppm can be obtained in solutions of graft copolymers at concentrations of 100–150 ppm. The grafting also improves the shear stability at higher Reynolds numbers. The shear stability of the graft copolymers at constant wall stress has been found to be superior to polyacrylamide and the mixtures of polyacrylamide and xanthan gum. In general, the shear stability of graft copolymers and polyacrylamide is shown to increase with concentration. The drag reduction characteristics and shear stability have been discussed in terms of structural features of the graft copolymers. The drag reduction characteristics of the graft copolymers are found to be similar to those of flexible polymers.     

ESR studies of the photodegradation of cellulose graft copolymers

Ultraviolet light induced free radicals in cellulose and cellulose graft copolymers were studied by means of ESR spectroscopy. At least six kinds of free radicals were formed in cellulose when the polymer was irradiated with ultraviolet light. Polystyrene and poly(methyl methacrylate) are more resistant to ultraviolet light than cellulose; however, the cellulose graft copolymers of polystyrene and poly(methyl methacrylate) were degraded by ultraviolet light. ESR studies revealed that photoinduced free radicals in cellulose graft copolymers were formed at the grafting branches of the copolymers rather than the cellulose backbone. The mechanisms of light stabilization and energy transfer reactions of cellulose and cellulose graft copolymers are discussed.     

Analysis of the solid phase copolymerization grafting process

Solid phase grafting, which is an emerging process for the production of graft copolymers, was analyzed and reviewed as an environmentally friendly and inexpensive graft copolymerization process. The effect of the process variables; amount of initiator, catalyst, interfacial agent, monomer, reaction temperature and reaction time were examined. Two graft copolymers, produced by solid phase grafting, were used to show differences in graft percentage by changing the process conditions. The two graft copolymers used were maleic anhydride graft onto polypropylene and acrylic acid graft onto polystyrene. A proposed mechanism was given for each example and characteristic bonds proposed in the PP-g-MA mechanism was positively identified by NMR spectroscopy. Graft levels of 4 wt% PS-g-AAc and 9.6 wt% PP-g-MA were obtained providing comparable or superior graft levels to other grafting processes. Successful scale-up of the solid phase technique proved that this process is efficient and marketable.     

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.     

Ataktisches polypropylen als pfropfgrundlage für die monomeren vinylacetat und vinylchlorid. Herstellung undeigenschaften der pfropfprodukte

The possibility of the application of atactic polypropylene is investigated as graft base for the preparation of graft copolymers of vinyl acetate and vinyl chloride respectively graft copolymers from vinyl acetate onto polypropylene as graft base for the preparation of graft copolymers of vinyl chloride in relation to the composition of the original mixture. After compounding of the graft products with polyvinyl chloride or ABS/polyvinyl-chloride mixtures selected mechanical properties are presented in relation to the quantity and composition of the incorporated graft copolymers.     

Temperature-sensitive hydrogel prepared by graft polymerization of N-isopropylacrylamide onto macroradical Pluronic

A new series of thermo-responsive graft copolymers were prepared via consecutive Pluronic backbone-initiated by t-butylperoxybenzoate with N-isopropylacrylamide (NIPAAm) onto Pluronic by a radical-induced graft polymerization technique. The thermal characterizations of the graft copolymers were investigated by differential scanning calorimetry (DSC). The Pluronic-g-poly(NIPAAm) copolymers exhibited sol-to-gel transitions depending on chain length of the grafted poly(NIPAAm) onto Pluronic. The graft copolymers indicated that the hydrophobic–hydrophilic balance achieved by varying contents of NIPAAm was an important parameter in controlling the transition temperature of the graft copolymers in solution and stability of the resultant gels. The data suggest that graft copolymers may be attractive substrates for tissue engineering and drug delivery applications as the combination of mechanistically independent gelation techniques with regard to gelation kinetics.     

Crystallization and morphology of starch-g-poly(1,4-dioxan-2-one) copolymers

The thermal transition, crystallization and spherulitic morphology of starch-g-poly(1,4-dioxan-2-one) copolymers were studied by means of differential scanning calorimetry (DSC) and polarized optical micrographs (PM). It is found that the graft structures of copolymers have obvious effects on the thermal and crystallization behaviors. Because there were more defect sites in the crystalline phase originating from the short grafted chains of poly(1,4-dioxan-2-one) (PPDO), the crystal structure of the copolymers was much less perfect than that of PPDO. PM revealed that the spherulitic morphology of the graft copolymers depended on graft structures and crystallization temperatures. From the single polarized micrograph of the graft copolymers it was observed clearly that the starch segments acted as nucleation sites. The Avrami equation was used to analyze the overall isothermal crystallization of the graft copolymers. Avrami exponents were almost constant at crystallization temperatures T_c ranging from 45 to 60 °C. Both the PM observation and the DSC investigation (crystallization rate constant, K values) indicated that the graft copolymers crystallize faster than pure PPDO, especially at higher crystallization temperatures.