微波技术在生物可降解聚合物合成中的研究进展

阐述了微波合成技术及微波化学仪器的发展历史,综述了微波辐射技术在生物可降解聚合物合成中的特点和优势,并针对其在直接缩聚法、开环聚合法以及共聚合成可生物降解聚合物中的应用和研究成果做了重点介绍。研究发现微波辐射技术具有大大降低聚合反应的时间和能耗,提高反应聚合速率、收率,且具有一定选择性的特性。而作为一种新型高效的加热方式,微波辐射技术为生物可降解聚合物合成甚至更多高分子材料的合成提供了新的思路。     

微波辐射用于聚酰亚胺的研究进展

聚酰亚胺因具有优良的综合性能而得到广泛的研究.微波辐射在高分子化学研究领域中的应用越来越广泛,效果也十分明显.与常规加热方式相比,微波辐射具有内部加热、缩短反应时间、提高反应产率、节省能耗、无温度梯度、制得产物性能好等优点.近年来,微波辐射用于聚酰亚胺的研究越来越多.因此本文对微波辐射在聚酰亚胺的合成、三阶非线性光学、聚酰亚胺复合材料以及稀土-聚酰亚胺配合物等方面的应用进行了综述.     

微波辐射在壳聚糖高分子材料中的应用

简述了微波促进有机反应的机理和特点，并对近年来微波辐射技术在壳聚糖高分子材料中的应用进展作一综述。     

高分子材料的微波辅助合成研究进展

微波加热以其省时、高效、清洁环保的显著优势而使微波辅助合成成为一种广受欢迎的合成技术。高分子材料的传统合成反应时间长、耗能大。将微波辐射应用于高分子材料的合成可缩短反应时间、降低反应能耗,已成为有机合成领域的研究热点。本文简要综述了微波辅助合成技术在工程材料高分子聚酰胺、聚酰亚胺、聚丙烯酸苄基酯以及在医用功能高分子、吸附功能高分子、导电功能高分子和光学功能高分子合成中的研究进展,并展望了微波辅助合成在高分子材料合成中的发展前景。     

原子转移自由基聚合与高分子构筑

活性聚合反应是目前高分子合成研究最为活跃的领域之一，原子转移自由基聚合反应（ATRP）是实现活性聚合的一种有效途径，可实现多种单体的活性聚合和可控自由基聚合。本文介绍了原子转移自由基聚合反应机理，重点综述了原子转移自由基聚合在高分子合成中的应用。     

我国高分子化学的研究现状和基金的管理导向

高分子化学是高分子科学的三大分支领域(高分子化学、高分子物理、高分子工程)之一,它的学科领域覆盖了聚合反应研究、高分子合成及高分子改性.由于高分子化学肩负着为高分子学科提供新高分子化合物的首要任务,因此是高分子科学的基础.我国从事高分子化学研究的科研人员,约占全部从事高分子研究人员的65%,因引高分子化学研究也是我国高分子科学研究队伍的主流(见表1).我国的高分子化学研究涉及新聚合反应及新聚合方法研究、聚合反应动力学研究、功能高分子的分子设计和     

超临界二氧化碳中的高分子合成

近年来,超临界二氧化碳（sc-CO2）在聚合反应中的应用受到了越来越多的关注。本文主要综述了以sc-CO2为反应介质的自由基聚合、阳离子聚合、过渡金属催化聚合、热致开环聚合、溶胶-凝胶聚合以及氧化耦合聚合的研究概况。一系列研究结果表明sc-CO2是非常有前途的反应溶剂,在高分子合成领域将会有更加广阔的应用前景。     

微波加热三氯化钕助染羊毛酸性染料染色研究

微波辐射技术在 70年代以后发展到化学领域 ,并得到广泛应用[1] 。利用微波辐射 ,常可大大加快反应速度 ,极大缩短反应时间。而稀土在毛纤维染色和鞣革中的应用已逐渐推广[2～ 5] ,但以微波辐射进行纤维染色的应用和研究鲜见报道 ,三氯化钕助染羊毛酸性染料也未见系统研究。本文研究酸性大红ＧＲ、酸性大红 3Ｒ在微波辐射下的染料稳定性、染羊毛时的上染率 ,对耐洗色牢度、耐熨烫色牢度、耐摩擦色牢度、耐汗渍色牢度进行了测定 ,并分析了微波染色的工艺条件。1　实验部分1 1　试剂材料色牢度专用羊毛布 (上海市纺织工业技术监督所 ) ;三氯…     

植物纤维微波辐射预处理的研究进展

综述了微波辐射预处理技术在植物纤维发酵、纸浆生产、木材加工三个化学加工中的应用研究进展。结果表明,微波辐射预处理能有效地提高植物纤维的化学反应和加工性能,而且预处理作用深度大,具有缩短反应时间,提高生产效率,降低生产能耗等优点。并且指出了微波辐射预处理植物纤维的不足:应用范围有限,其工业化研究处于探索阶段;升温快,反应过程不易控制。最后提出未来研究的重点:微波辐射预处理植物纤维加速反应机理、温度的控制和检测方法等方面。     

有机小分子催化ε-己内酯开环聚合反应

聚己内酯(PCL)是一种生物可降解高分子材料,具有良好的环境、生物相容性,广泛应用于生物医学、包装等领域。有机小分子催化ε-己内酯单体开环聚合反应是制备聚己内酯的主要方式之一。与传统的金属催化相比,有机催化不仅反应条件温和、聚合可控,而且还可解决聚合物中金属残留问题,是目前高分子合成化学的研究热点。本文按照催化体系的不同活化方式,讨论了近年来有机催化在ε-己内酯开环聚合反应中的研究进展,归纳总结了不同催化体系的优缺点,并在此基础上展望了有机小分子催化剂在ε-己内酯开环聚合反应中的发展趋势和应用前景。     

Microwave Assisted Synthesis of Poly(ether sulfone) – An Efficient Synthetic Route to Control Polymer Chain Structure

A novel synthetic process for the efficient control over molecular weight of the poly(ether sulfone) has been studied. The application of microwave irradiation for the condensation polymerization to synthesize poly(ether sulfone) is demonstrated. Microwave assisted polymerization results in significant reduction of reaction time. Microwave based process is also feasible at lower temperature for the synthesis of poly(ether sulfone). Polymers synthesized have been characterized using NMR and FTIR spectroscopy. Polymer film morphology and surface composition have been studied using SEM and EDX. An increase in the molecular weight is observed with increasing microwave irradiation time.     

Microwave Effects Due to Anionic or Cationic Initiators in Emulsion Polymerization Reactions

Summary: Emulsion polymerization reactions were performed under microwave irradiation and conventional heating using anionic or cationic initiators and surfactants. Microwave irradiation promoted higher reaction rates for both initiators and surfactants, in comparison with the conventional heating. The effect of high power microwave irradiation was studied using a method of cycles of heating and cooling, where rapid polymerization reactions were obtained. In the reactions with anionic initiator and surfactant, a decrease in the particle diameters was observed with microwave heating, and even smaller particles were obtained using high power microwave irradiation. Moreover, the decrease in the particle size was acompanied by an increase in the polymer molecular weight. On the other hand, these effects were not observed for reactions with cationic initiator and surfactant.     

微波技术在催化剂制备中的应用

微波作为一种独特的加热手段在化学领域已得到广泛应用。本文综述了微波技术在催化剂的合成、活性组分的负载等方面的研究应用,重点探讨了在分子筛催化剂的合成中微波技术所表现出的优越性,对微波合成催化剂的作用机理及影响因素作了评述,并展望了微波技术在催化领域的发展前景。     

Microwaves in organic synthesis. Thermal and non-thermal microwave effects

Microwave irradiation has been successfully applied in organic chemistry. Spectacular accelerations, higher yields under milder reaction conditions and higher product purities have all been reported. Indeed, a number of authors have described success in reactions that do not occur by conventional heating and even modifications of selectivity (chemo-, regio- and stereoselectivity). The effect of microwave irradiation in organic synthesis is a combination of thermal effects, arising from the heating rate, superheating or "hot spots" and the selective absorption of radiation by polar substances. Such phenomena are not usually accessible by classical heating and the existence of non-thermal effects of highly polarizing radiation--the "specific microwave effect"--is still a controversial topic. An overview of the thermal effects and the current state of non-thermal microwave effects is presented in this critical review along with a view on how these phenomena can be effectively used in organic synthesis.     

Cross-metathesis assisted by microwave irradiation

Microwave irradiation effectively accelerates cross-coupling metathesis reactions between deactivated olefins. Reactions have been carried out with the phosphine-free Hoveyda-Grubbs catalyst and the "second generation Grubbs' catalyst." While there have been reports that a "microwave effect" is observed in various transformations, the accelerations we observe are due to the efficient and rapid heating and increased pressure in the microwave apparatus.     

Hot or not—the influence of elevated temperature and microwave irradiation on the solid phase synthesis of an affibody

Despite the advances of solid phase peptide synthesis (SPPS) the synthesis of long peptides is still challenging. Microwave irradiation and conventional heating are considered to improve the efficiency of SPPS. It has been shown that conventional heating and heating by microwave irradiation improves the efficiency of solid phase synthesis of peptides that are prone to aggregation as compared to the synthesis at room temperature. In this Letter, the influence of elevated temperature and microwave irradiation on the homogeneity of the synthesis product of a 58-mer peptide affibody has been compared. A detailed analysis by high resolution HPLC and LC-MS mass spectrometry using a high-mass resolution Orbitrap Exactive mass spectrometer was performed. This study revealed that neither thermal heating nor microwave heating improves the yield and purity of the crude product as compared to the synthesis at room temperature. In contrast, the formation of undesirable side products rather increased by microwave irradiation. These results indicate that neither heating nor microwave enhancement of solid phase synthesis does allow a significant improvement of peptide sequences with a low aggregation potential.     

Microwave-assisted reactions in heterocyclic compounds with applications in medicinal and supramolecular chemistry

Microwave irradiation has been successfully applied in organic chemistry. Spectacular accelerations, higher yields under milder reaction conditions and higher product purities have all been reported. Indeed, a number of authors have described success in reactions that do not occur under conventional heating and modifications in selectivity (chemo-, regio- and stereoselectivity) have even been reported. Recent advances in microwave-assisted combinatorial chemistry include high-speed solid-phase and polymer-supported organic synthesis, rapid parallel synthesis of compound libraries, and library generation by automated sequential microwave irradiation. In addition, new instrumentation for high-throughput microwave-assisted synthesis continues to be developed at a steady pace. The impressive speed combined with the unmatched control over reaction parameters justifies the growing interest in this application of microwave heating. In this review we highlight our recent advances in this area, with a particular emphasis on cycloaddition reactions of heterocyclic compounds both with and without supports, applications in supramolecular chemistry and the reproducibility and scalability of organic reactions involving the use of microwave irradiation techniques.     

A Novel Production Route for Nylon-6: Aspects of Microwave-Enhanced Catalysis

Summary: Microwave irradiation was used for the amidation of a nitrile with an amine with a freshly prepared zirconium-based heterogeneous catalyst. Microwave irradiation selectively heats the catalyst which enhances its activity as compared to conventional heating. The difference between microwave heating and conventional heating disappears when Zr(OH)₄ is used instead of ZrO₂, indicating a microwave-induced shift in the hydrolysis equilibrium, i.e. the distribution of ZrO₂, ZrO(OH)₂ and Zr(OH)₄, of the zirconium-based catalyst. The catalyst efficiently catalyzes the amidation of valeronitrile with n-hexylamine with conventional as well as with microwave heating. Zr(OH)₄ was also used for the polymerization of 6-aminocapronitrile using conventional and microwave heating. With both heating methods a relatively low molecular weight polymer with a M_n of 4000 g/mol was obtained in a sealed vessel, due to the presence of water and ammonia. A post-polymerization step under microwave irradiation, with active removal of water and ammonia shifts M_n to 10000 g/mol. Pressure decrease to facilitate water removal resulted in products with higher molecular weights. A pressure reduction to 50 Pa and operation in an argon atmosphere at 230 °C resulted in nylon-6 with a M_n of 65000 in rather short reaction times. Lower pressures led to end-biting and evaporation of the volatile ε-caprolactam at 230 °C. As a consequence the resulting product has than a much lower molecular weight. The combination of a heterogeneous zirconium based catalyst and microwave heating is promising for process intensification for nylon-6 production.     

液相微波介电加热法制备纳米粒子的研究进展

随着纳米科技的飞速发展,合成纳米材料的新方法层出不穷。在这些新方法当中,液相微波介电加热法近年来得到了飞速的发展,引起了科学界越来越多的关注。本文介绍了近年来液相微波介电加热法制备纳米粒子的一些研究进展,主要是该方法在制备金属、过渡金属氧化物和金属硫族化合物纳米粒子中的应用,并且对该领域未来的发展作了一些展望。