聚合物多元醇对PU-RIM材料的耐热性影响研究

对高活性聚合物多元醇在PU-RIM材料中的应用进行了研究,考察了聚合物多元醇对材料生产工艺性能与耐热性的影响.结果表明:该类多元醇由于含有大量苯环、丙烯腈等极性基团,可减小材料的热下垂,改善材料的动态热力学性能.     

低成本湿法合成革用聚酯型耐水解聚氨酯树脂的合成

以苯酐聚酯二元醇(PS)、聚己内酯多元醇(PCL)、1,4-丁二醇(BDO)、二苯甲烷二异氰酸酯(MDI)等为原料,合成了湿法革用聚氨酯树脂.分别研究了PS相对分子质量、PCL用量、硬段含量等对聚氨酯树脂膜的模量及其耐水解性能的影响.结果表明,PS和PCL复配可以制得耐水解性能优异,且成本较低的湿法合成革用聚氨酯树脂.     

气雾剂单组份聚氨酯泡沫塑料的研制

根据聚氨酯泡沫塑料的发展趋势,研制气雾剂形式的单组份聚氨酯泡沫。通过研究分析聚醚多元醇和多异氰酸酯的反应原理以及与烃类抛射剂等相关特性,把以上材料以不同的比例,方式灌装于马口铁气雾罐中进行开发,研究。经过一系列的试验,该产品开发配方通过了相关应用测试及稳定性试验。具有广阔的市场前景。     

新型聚酯多元醇水分散体的制备

先采用间苯二甲酸-5-磺酸钠(5-SSIPA)与新戊二醇(NPG)反应制得聚酯中间体,再将一定量的聚酯中间体与多元羧酸和多元醇进行反应,同时引入叔碳酸缩水甘油酯(CARDURAE-10),制备了聚酯多元醇水分散体.用红外光谱(FT-IR)和激光粒度分析仪对产物结构及其稳定性进行了表征;并考察了5-SSIPA/NPG对聚酯中间体的影响及合成工艺、催化剂、聚酯中间体用量、叔碳酸缩水甘油酯对反应体系的影响.结果表明:选择合适的合成工艺或加入催化剂可明显缩短反应时间;聚酯中间体用量约为单体总质量的12%时,得到的产物稳定性较好;叔碳酸缩水甘油酯的引入能有效降低树脂的黏度、减小水分散体粒径,并提高涂膜最终的耐酸、耐碱及耐水性能.     

多元醇法制备银纳米棒的放大试验影响因素研究

采用银晶种为引导剂,以高浓度硝酸银溶液为银源,乙二醇为还原剂,聚乙烯吡咯烷酮为盖帽剂,大规模制备银纳米棒。用扫描电镜,元素分析和X射线衍射对银纳米棒进行表征。结果表明,通过预加银晶种的方式替代添加金属盐类,最佳的反应条件为:搅拌速度为350 r/min,反应温度为160℃,硝酸银浓度不高于0.50 mol/L,采取体积放大6倍高浓度硝酸银制备银纳米棒时,需要提高银晶种的浓度为9.81 mmol/L,PVP/AgNO3摩尔比为1.3,该方法利用银晶种的引导作用,调控硝酸银的还原速度使之与银纳米棒的生长速度相匹配。     

废旧聚酯改性漆包线绝缘漆的性能研究

采用溶胶凝胶法制备Al2O3溶胶,以废旧聚酯塑料瓶和Al2O3溶胶为原料制备聚酯多元醇溶液,然后将聚酯多元醇溶液与氨基树脂、环烷酸锌混合制成聚酯漆包线漆。通过红外光谱和X射线衍射分析对聚酯漆包线漆进行分子结构和物相表征。测试改性聚酯漆包线漆的热冲击、耐电压、介质损耗等性能。结果表明:Al2O3掺杂质量分数为10%时,制得的改性聚酯漆包线漆的性能最佳,介质损耗曲线的拐点温度可达到179℃,耐热性能明显提高。     

Controlled synthesis and properties of palladium nanoparticles

In our research, the preparation processes of Pd nanoparticles (Pd NPs) with different methods by adding a certain amount of silver nitrate, iron chloride or sodium iodide are presented in order to control their size and morphology. Various sizes and shapes of Pd NPs are observed by alcohol reduction. The results show the size and morphology control of Pd NPs with chemical reductions of Pd salts by ethanol and ethylene glycol (EG) that have very different reduction processes. The modified polyol method with the gradual addition of Pd and polyvinylpyrollidone precursors in EG at 160°C has led to control their size and morphology in the 10?nm range using 0.02?M AgNO₃. It is observed that the Pd nanorod is also formed. The main factors that will control the shapes of Pd NPs have been presented to explain their growth and formation mechanisms in a control process.     

Preparation of semirigid polyurethane foam with liquefied bamboo residues

Bamboo residues were liquefied by using a solvent mixture consisting of polyethylene glycol 400 and crude glycerol (4/1, w/w) with 98% sulfuric acid as catalyst at 160°C for 120 min. The liquefied bamboo had hydroxyl values from 178 to 200 mg KOH/g and viscosities from 507 to 2201 mPa S. The obtained bamboo‐based polyols were reacted with various amounts of polyaryl polymethylene isocyanate (PAPI), using distilled water as blowing agent, silicone as surfactant, and triethylenediamine and dibutyltine dilaurate as cocatalyst to produce semirigid polyurethane (PU) foams. The [NCO]/[OH] ratio was found to be an important factor to control the mechanical properties of PU foams. At a fixed [NCO]/[OH] ratio, both density and compressive strength of PU foams decreased with the increase of bamboo content. The microstructure of PU foams indicates that [NCO]/[OH] ratios are important for cell formation and chemical reactions. The uniformity and cell structure of the foams are comparable to their corresponding compressive strengths. Moreover, the thermogravimetry analysis showed that all the semirigid PU foams had approximately the same degradation temperature of about 250 to 440°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of support type and synthesis conditions on the oxygen reduction activity of RuxSey catalyst prepared by the microwave polyol method

Ru_xSe_y nanoparticles supported on different carbon substrates were synthesized by microwave heating of ethylene glycol solutions of Ru(III) chloride and sodium selenite at different pH and Ru/Se mole ratios. The resulting catalysts were used for the electrochemical oxygen reduction reaction (ORR) in acidic solution. The electrochemical activity was highest for the supported catalyst synthesized at pH 8. Increasing the Se concentration of the catalyst up to 15 mol% increased the catalytic activity for the ORR; at this Se concentration, the activity of the catalyst was considerably higher than that observed for pure Ru catalyst synthesized at exactly the same conditions. The influence of the type of carbon support on the activity of the electrocatalyst was also investigated. Among the different supports, including carbon black (Vulcan XC-72R) (C1), and nanoporous carbons synthesized from resorcinol- (C2) and phloroglucinol-formaldehyde (C3) resins, the Ru_xSe_y catalyst supported on C3 exhibited highest activity for ORR.     

橡胶籽油基多元醇的制备与表征

以环氧橡胶籽油（ERSO）为原料,甲醇和异丙醇为开环试剂,氟硼酸为催化剂,制备橡胶籽油基多元醇,以产物羟值为指标对制备工艺进行了优化,并对产物进行了表征。研究结果表明,橡胶籽油基多元醇的最佳制备条件为反应时间30min,反应温度70℃,醇与ERSO的质量比为4：1,氟硼酸用量为ERSO质量的1%,异丙醇与甲醇质量比为1：1。通过验证实验可知,在此条件下制备的橡胶籽油基多元醇酸值为2.68mg/g,羟值为219.32mg/g,平均相对分子质量为870.21,含水量为0.08%,黏度为4791mPa·s。同时,通过FT-IR、¹H NMR和¹³C NMR分析表征了橡胶籽油基多元醇的化学结构,结果表明,ERSO中的环氧基发生了开环反应,生成了多元醇。