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21.
采用2,2,6,6-四甲基哌啶-1-氧基(TEMPO)/Na Br/Na Cl O氧化体系将纤维素膜C6位上的羟基氧化为羧基,再利用水溶性偶合试剂N-(3-二甲氨基丙基)-N'-乙基碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)将3-氨基苯硼酸与氧化纤维素膜以形成酰胺键的方式结合起来,从而制备出接枝有苯硼酸官能团的纤维素膜。文中对苯硼酸改性纤维素膜进行了结构表征与力学性能检测,并对改性过程中各因素的影响进行了讨论。结果表明,当TEMPO的用量为0.005 g,Na Br的用量为0.025 g,10%的Na Cl O溶液的用量为4 m L及氧化时间控制在60 min以内时,可以获得力学强度较好的纤维素膜。此外,该膜对含有多醇结构微粒的吸附与解吸过程可通过p H值控制来实现。鉴于苯硼酸结构对多醇类化合物具有的探针作用,所制得的改性纤维素膜在快速方便检测糖尿病等方面具有潜在的应用价值。  相似文献   
22.
Vanadium pentoxide nanoparticles were synthesized using a solvo-thermal method and were characterized via X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The ozonation of palm oil was performed by using vanadium pentoxide nanoparticles as catalysts to synthesize ethyl malonate. This procedure presented several advantages, such as simple operation for a precise ozonation, excellent yield, short reaction times and reusability because of the recyclability of palm oil. Ethyl malonate was synthesized via the one-step ozonolysis of palm oil and was spectroscopically characterized using gas chromatography-mass spectroscopy (GC-MS).  相似文献   
23.
Rubber seed oil having high free fatty acid content and high unsaturation was used to obtain high quality polyurethane resins through epoxidation and ring opening with methanol and free fatty acids. Two polyols prepared with free fatty acids and without were cured with modified methylene diphenyl diisocyanate to obtain strong, high modulus glassy polyurethanes. The effect of structure on thermal and mechanical properties was analyzed. This showed that the polyol with free fatty acid utilized to obtain a branched structure gave superior crosslinking density and mechanical properties. © 2016 Society of Chemical Industry  相似文献   
24.
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。  相似文献   
25.
The explosion of the palm oil industry in recent decades has transformed vast swathes of the Malaysian and Indonesian countryside. Milica Topalovic , Assistant Professor of Architecture and Territorial Planning at ETH Zurich, asserts that the resulting agro-industrial landscapes challenge the very concept of what is rural, and considers how such areas should be conceptualised.  相似文献   
26.
为了优化聚氨酯(PUR)包膜尿素控释性能,采用多亚甲基多苯基异氰酸酯分别与聚酯和聚醚多元醇按不同配比混合,依照不同次序先后喷涂在尿素颗粒表面制备聚酯型和聚醚型PUR互换层包膜尿素并利用分光光度法研究其控释性能。通过接触角、热重分析和扫描电子显微镜对膜材的润湿性、热稳定性和形貌进行了表征,并采用傅立叶变换红外光谱分析了尿素释放过程中膜层的结构变化。结果表明,聚酯型PUR的疏水性弱于聚醚型PUR,但热稳定性高于后者;两者的包覆次序影响PUR包膜尿素的控释效果,聚酯型PUR为外层、聚醚型PUR为内层时控释性能优良,当两者包覆比例(质量比)为1.5∶1.5时,释放期最长可达84 d。  相似文献   
27.
In this research a new heterogeneous catalyst has been prepared for biodiesel production. The catalyst was prepared by sulfonating industrial sugar waste. Unlike homogeneous catalysts, which require further purification and separation from the biodiesel production reaction media, this inexpensive synthetic catalyst does not need to go through an additional separation process. This advantage consequently minimizes the total application costs. The catalyst was prepared by partially carbonizing sugar beet pulp at 400 °C. The carbonization product was then sulfonated with concentrated H2SO4 vapor in order to produce a solid catalyst. The prepared catalyst was used in the esterification reaction between palm fatty acid distillate (PFAD) and methanol. The effects of the temperature, methanol/PFAD ratio, reaction time and catalyst dosage on the efficiency of the production were individually investigated. The optimum biodiesel production occurred at 85 °C, a reaction time of 300 min, catalyst dosage of 3 g and methanol/PFAD ratio of 5:1 (mol/mol), lowering the acid value from 198 to 13.1 (mg KOH/g oil) or the equivalent, with a fatty acid methyl ester yield of around 92 %. The results suggest that the synthesized inexpensive catalyst is useful for biodiesel production from PFAD.  相似文献   
28.
The impact of replacing three polyether polyols with different levels of a single palm olein‐based natural oil polyol (NOP) was systematically correlated with the changes in foaming reactivity, cell structure, physico‐mechanical properties, and morphology of viscoelastic (VE) foams. The data show that replacing the polyether polyols with the NOP slightly increased the rate of the foaming reactivity. Increasing the NOP content resulted in increased cell size and cells remained fully open. Increased NOP content contributed to higher load bearing properties of VE foam, which can be attributed to higher functionality of NOP compared to polyether polyols. Addition of the NOP slightly increased the resilience of the foams, however, the hysteresis which is the measure of energy absorption remained mostly unaffected. Age properties, characterized by dry and humid compression sets, were mostly unaffected by the replacement of the polyether polyol with the NOP. The addition of NOP did not impact the morphology of the VE foam polymer matrix, which appears to retain a low degree of hard and soft segment domain separation. Overall, the results demonstrate a feasibility that the NOP can be used to partially replace the polyether polyols in VE polyurethane foams without significant impact on the functional performance.  相似文献   
29.
高耐候、耐磨型聚氨酯风电叶片涂料的研究   总被引:1,自引:0,他引:1  
采用丙烯酸树脂和聚酯多元醇树脂拼用的方法制备了高耐候、耐磨型聚氨酯风电叶片涂料。通过改变丙烯酸树脂与聚酯多元醇树脂质量比设计了5个不同配方,分别对其涂膜性能进行表征并与某进口样品对比。试验表明,随着丙烯酸树脂用量的增加,涂膜的耐候性能随之变好;而增加聚酯多元醇用量时,则产品的耐冲击性能、附着力及耐磨性变优。所研制产品的耐磨性和附着力要优于某进口产品,且耐候性能与某进口产品相当。  相似文献   
30.
通过大量实验寻找出简易、有效制备PIPA多元醇的工艺,并通过红外测试证实了产物的合理性。还探讨了温度、固含量、异氰酸酯指数、水的量等因素对反应体系的影响,并指出了合成过程中,以上因素的合理用量。如果在制备PIPA多元醇时加入少许稳定剂,则可以很好地提高PIPA多元醇的稳定性。  相似文献   
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