首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
研究了EtOH-H2O,n-PrOH-H2O,i-PrOH-H2O体系在CS膜和PEO/CS共混膜中的渗透蒸发性能。讨论了料液温度、料液浓度、共混膜组成对分离性能的影响,结果发现PEO的掺入能大大提高cs膜的渗透通量;而分离因子下降。同时从膜材料的聚集态结构出发对相关的渗透蒸发行为进行了讨论。对于PEO/CS共混膜,膜内自由体积的大小是影响分离性能的主要因素,小分子在膜中的渗透蒸发行为主要是由扩散过程控制的。本文还研究了PEO的掺入对壳聚塘膜强度的影响以及利用DSC谱研究PEO掺入后壳聚糖膜聚集态结构的变化。  相似文献   

2.
研究了EtOH-H2O,n-PrOH-H2O,i-PrOh-H2O体系在CS膜和PEO/CS共混膜中的渗透蒸发性能。讨论了料液温度、料液浓度、共混膜组成对分离性能的影响,结果发现PEO的掺入能大大提高CS膜的渗透通量,而分离因子下降。同时从膜材料的聚集态结构出发对相关的渗透蒸发行为进行了讨论。对于PEO/CS共混膜,膜内自由体积的大小是影响分离性能的主要因素,小分子在膜中的渗透蒸发行全为主要是由扩  相似文献   

3.
LLDPE/LDPE共混体系的相容性与性能   总被引:3,自引:0,他引:3  
杨毓华  李喜 《应用化学》1996,13(5):88-90
LLDPE/LDPE共混体系的相容性与性能杨毓华,花荣,白春霞,于旻李三喜,葛铁军(中国科学院长春应用化学研究所长春130022)(沈阳化工学院高分子系沈阳)关键词DSC,WAXD,力学性能,LLDPE,LDPE,共混,相容性非晶-非晶-结晶共混体系...  相似文献   

4.
测定了聚氯乙烯(PVC)-丁腈橡胶(NBR-29)-氯丁橡胶(CR)三元共混物的冲击性能和应力-应变行为,用动态力学分析、扫描电镜和透射电镜研究了共混物的相容性和形态结构,结果表明,NBR-29对PVC,CR有良好的增容作用,三元共混物是部分相容的二相体系,具有良好的抗冲击性能。  相似文献   

5.
为了表明马来酸酐接枝聚烯烃后对聚酰胺的相容作用,本文研究了聚酰胺1010(PA1010)/聚乙烯-马来酸酐接枝共聚物(PE-g-MAH)共混物在不同MAH接枝量下的结晶性与力学性能。研究表明,MAH的存在导致PE-g-MAH-co-PA1010共聚物的形成,而该共聚物在标题共混物中起着相容剂的作用。共混物的结晶性能变化显示了共混组分间存在一定程度的混溶性。在一定的MAH含量内,标题共混物具有协同效应。  相似文献   

6.
聚氯乙烯—丁腈橡胶—氯丁橡胶三元共混物的研究   总被引:1,自引:0,他引:1  
测定了聚氯乙烯(PVC)-丁脯橡胶(NBR-29)-氯丁橡胶(CR)三元共混物的冲击性能和应力-应变行为,用动态力分析、扫描电和透射电镜研究了共混物的相容性和形态结构。结果表明,NBR-29对PVC,CR有良好的增容作用,三元共混物是部分相容的二相体系,具有良好的抗冲击性能。  相似文献   

7.
采用二甲基硅氧烷-b-乙二醇嵌段共聚物(DMS-b-OE)对聚二甲基硅氧烷/聚氨酯(PDMS/PU)共混体系的增容,重点研究了增容共混体系的微观形态结构和软科学性能之间的关系。扫描电子显微镜、动态力学分析和力学性能测试结果表明:DMS-b-OE对PDMS/PU具有优良的增容作用,改善了PDMS/PU共混体系的相容性,提高了该共混物的力学性能。其抗张强度由3.4MPa提高到7.6MPa。  相似文献   

8.
采用不同的共混方式-溶液法、熔融法Ⅰ(简单机械共混)和熔融法Ⅱ(存在酯-酰胺交换反应)将聚对苯二甲酸乙二酯(PET)与聚酰胺66(PA66)共混,研究了共混体的形态结构和流变性能,探讨了对甲苯磺酸(TsOH)催化下的酯-酰胺交换反应和PET/PA66共混体系的相容性.  相似文献   

9.
采用不同的共混方式-溶液法,熔融法I(简单机械共混)和熔融法Ⅱ(存在酯-酰胺交换反应)将聚对苯二甲酸乙二酯与聚酰胺66共混,研究了共混体的形态结构和流变性能,探讨了对甲苯磺酸催化下的酯-酰胺交换反应和PET/PA66共混体系的相容性。  相似文献   

10.
用DSC和WAXD方法研究了高密度聚乙烯/聚(乙烯丙烯辛烯-1)(HDPE/EPO)共混体系的结晶性能。共混物的DSC曲线皆呈单峰,表明共混体系形成了共晶。晶胞参数a及结晶度随共混物组成而变,进一步证明HDPE/EPO共混体系的相容性.  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

14.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

15.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号