环保型透明双组分改性聚氨酯胶黏剂的研究

报道了一种无溶剂、双组分、透明环氧改性聚氨酯胶黏剂,利用红外光谱法跟踪探讨了合成机理,分析了各基团之间的化学反应及其产物随时间的变化。结果表明:改性后聚氨酯的许多性能得到改进;在最佳原料配比及适宜的实验条件下,产品黏度适中,流动性好,性能稳定,储存期长;在m(合成环氧改性聚氨酯)∶m(固化剂)=5∶3的条件下,室温表干时间约45 min,剪切强度大于19 MPa,产品为韧性,耐溶剂、耐温性优良,固化过程中不起泡,用于粘接及灌封时美观。     

我国固体火箭发动机衬层成型技术进展

衬层是推进剂与绝热层或壳体之间的高分子弹性体涂层，衬层成型是固体火箭发动机生产中的一种特种工序。我国固体火箭发动机衬层成型工艺如离心成型、刷涂、拉涂、喷涂等工艺不断向前发展。综述我国固体火箭发动机衬层成型工艺的现状和发展，介绍了无溶剂高固体份衬层抛涂成型新技术的试验结果。     

Optimization of citrus peels D-limonene extraction using solvent-free microwave green technology

Attention is presently drawn to the development of a new and green alternative technique for the extraction of essential oil from citrus plant materials. This study was aimed at the extracting essential oil from orange and lemon peels using solvent-free microwave method. This process uses microwave-assisted hydro-diffusion technique to extract essential oil from citrus peels. Response surface methodology was used to investigate the effect of microwave power (200–1,000?W) and extraction time (10–40?min) on the essential oil yield. The oil extracted was characterized using Fourier transform infrared radiation (FTIR) and Gas chromatography–mass spectrometry analysis to determine the functional groups and chemical components present, respectively. The optimum yield of extract from orange and lemon peels were 3.7 and 2.0%, respectively at corresponding power of 1,000?W and time of 10?min. The analysis of variance results showed that the resulting models for both orange and lemon peels were significant and microwave power had greater influence on the extraction processes at both linear and quadratic levels. The FTIR analysis revealed prominent functional groups of alkenes that majorly constitute limonene compound at 1,642 and 1,643?cm^?1 for orange and lemon peels, respectively. The present process permits fast and efficient extraction, avoids water and solvent consumption, and allows substantial energy savings.     

软包装用无溶剂型聚氨酯复膜胶的发展概况

综述了国内外软包装用无溶剂型聚氨酯(PU)复膜胶的发展概况,并针对其面临的主要问题提出了今后的发展方向。随着人们对环保要求日趋严格,绿色环保的无溶剂型复膜胶必将在复合软包装行业中得到迅速而广泛的应用。     

无溶剂型双组分有机硅改性PU胶粘剂的制备与性能研究

以聚醚二元醇(DL-1000)、4,4′-二苯基甲烷二异氰酸酯(MDI)为主要原料合成端-NCO基PU(聚氨酯)预聚体;然后以γ-氨丙基三乙氧基硅烷(KH-550)对其进行嵌段共聚改性,并以3,3′-二氯-4,4′-二氨基二苯基甲烷(MOCA)/蓖麻油作为复合固化剂,制备出无溶剂型双组分有机硅改性PU胶粘剂。研究结果表明:硅烷键已引入PU胶粘剂中;随着KH-550含量的不断增加,胶粘剂的黏度增大、固化时间缩短、室温剪切强度下降且耐热性增强;通过调节不同KH-550含量,可制备出不同性能要求的胶粘剂;该胶粘剂的玻璃化转变温度(-45.9℃)相对较低,说明其耐寒性相对较好。     

Extraction of Essential Oil from Laurel Leaves by Using Microwaves

Abstract

The effects of microwave power and time in solvent-free microwave extraction (SFME) on the yield and composition of the essential oil obtained from laurel (Laurus nobilis L.) leaves were studied. The extraction was also performed by hydrodistillation as a control. Specific gravities and refractive indices of the essential oils obtained by different methods and at various conditions were also examined. The main constituent of laurel essential oil was 1,8-cineole (630–730 mg/mL). Essential oils obtained by SFME and hydrodistillation were comparable with respect to both yield and composition while the process time was reduced by 55–60% when SFME was used.     

无溶剂水性聚氨酯乳液的研制

采用预聚体法合成无溶剂水性聚氨酯。探讨了扩链剂的添加顺序,nNCO/nOH比例、二羟甲基丙酸(DMP))含量等因素对水性聚氨酯乳液性能的影响。结果表明:当nNCO/nOH比例为1.3左右,DMPA用量为6%,先添加亲水性扩链剂DMPA时,乳液的综合性能最佳。     

Nanosilica Supported Dual Acidic Ionic Liquid as a Recyclable Catalyst for the Rapid and Green Synthesis of Polycyclic Phenolic Compounds

Generally ionic liquids have gained increasing attention in organic synthesis as catalyst and solvent. However, there are some drawbacks, including the difficulties in the product purification, ionic liquid recycling, and use of excess amounts of the expensive ionic liquid when the ionic liquid is used in the organic reactions. In addition, the high viscosity of ionic liquids can lead to mass transfer limitations in fast chemical reactions. These problems can be overcome by the use of supported ionic liquid phases. In this article, a simple, efficient and green method has been developed for the synthesis of bisphenolic antioxidants by the reaction of 2-tert-butyl-4-methylphenol and aldehydes in the presence of nanosilica supported dual acidic ionic liquid (NSSDAIL) as robust and reusable catalyst under solvent-free conditions. Three different NSSDAILs were synthesized and characterized using SEM, BET, IR, and XRD techniques. High yields of the products, short reaction times, use of a non corrosive, non toxic and reusable catalyst, and use of solvent-free condition are the worthwhile advantages of the current method.     

无溶剂萃取技术在食品中农药残留分析的研究进展

无溶剂萃取技术是一种先进的样品制备与前处理技术,常用的有气相萃取、超临界流体萃取、固相萃取、固相微萃取等方法。本文综述了无溶剂萃取技术的基本原理及在食品中农药残留的研究应用进展。     

水滑石高效催化缺电子烯与胺类的共轭加成反应

The novel efficient procedure has been developed for the conjugate addition of amines to electron deficient alkenes. A series of hydrotalcite-like materials were synthesized as catalyst for the conjugate addition of amines and alkenes. After optimizing the reaction conditions, ZnAl-LDHs (3︰1) was chosen as the best catalyst for the reaction. The results showed that the catalyst worked very well for the conjugate addition of amines to electron deficient alkenes with the excellent yields in several minutes. Operational simplicity, no solvent, low cost of the catalyst, high yields, reusability, excellent chemoselectivity, wide applicability are the key features of this method.