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 105 毫秒
1.
环氧树脂/玻璃纤维复合界面的电子能谱化学分析   总被引:1,自引:0,他引:1  
姚映钦  赵斌元  陈品华  王典芬 《分析化学》1999,27(10):1175-1178
采用化学分析用电子能谱技术分别对机械剥离后的玻璃纤维布和短切玻璃纤维增强环氧树脂试样的玻璃纤维面作了对比分析,发现树脂残留物表面上有富裕的环氧基,证明剥离不是发生在树脂/玻璃纤维(布)粘结界面上,而是发生在粘结界面附近的树脂层里;环氧树脂/玻璃纤维布界面比环氧树脂/短切玻璃纤维界面有更强的界面增强效应。  相似文献   

2.
DAIP树脂及其复合材料的性能研究   总被引:3,自引:2,他引:1  
加入热固性丁苯树脂可降低DAIP树脂的酯键密度,提高其耐水性,在该体系中加入适量的偶联剂,可改善树脂与玻璃纤维的界面,提高复合材料的耐水性和介电性能。  相似文献   

3.
用MonteCarlo方法对两嵌段共聚高分子在固液界面的吸附进行模拟,获得了固液界面区吸附链节的分布和吸附构型大小分布等微观信息.考察了吸附性链节的吸附能εAa和两嵌段共聚高分子中吸附性链节比例f对固液界面区高分子链节的分布和各种吸附构型大小的影响.结果表明,吸附层厚度主要由两嵌段共聚高分子中非吸附性链段的长度决定.  相似文献   

4.
竹纤维具有密度低、强度高、价格低和可再生等优点,是工程结构材料中的理想增强材料。以竹纤维增强聚丙烯是目前制备高性能聚丙烯复合材料的研究热点,也是可持续发展的重要方向之一。为得到高性能的复合材料,需要对竹纤维和聚丙烯基体界面进行处理。本文综述了改善竹纤维与聚丙烯基体界面相容性的三种方法,包括竹纤维的表面改性、聚丙烯基体的改性和添加第三组分,指出了三种方法的优缺点,并展望了提高竹纤维/聚丙烯复合材料界面相容性的研究方向。  相似文献   

5.
采用电感耦合射频等离子体(ICP)和介质阻挡放电(DBD)低温等离子体对高性能连续纤维表面进行改性,分别采用X光电子能谱(XPS)、原子力显微镜(AFM)和动态接触角测定仪(DCA)等分析测试手段系统地研究了等离子体处理时间、放电功率、放电气压等对连续碳纤维、聚苯并二噁唑(PBO)纤维改性处理前后,纤维表面状态、表面组成、表面形貌、浸润性能的变化规律以及经等离子体处理前后纤维增强双马树脂基复合材料界面结构与性能的影响关系及变化规律、复合材料界面粘结和破坏机理.研究结果表明,经过等离子体处理后,纤维表面接枝上了大量的含羧基、羟基等极性官能团,表面粗糙度增加,表面自由能增加,纤维浸润性能得到明显改善,导致纤维与双马树脂基体界面层间剪切强度(ILSS)明显提高,复合材料的破坏模式由未处理的界面脱粘破坏转变为等离子体处理后的树脂基体破坏.最后,对纤维表面时效性及其对纤维增强双马树脂基复合材料界面性能的影响关系也进行了论述.  相似文献   

6.
聚丙烯-聚乙烯嵌段共聚物的分子结构及性能的研究   总被引:5,自引:1,他引:5  
本工作用核磁共振(~(13)C-NMR)、示差扫描量热(DSC)、动态力学分析(DMA)和扫描电子显微镜(SEM)等技术研究了将丙烯、乙烯单体两步分段共聚、预期为聚丙烯-聚乙烯嵌段共聚物的合成物(简称为聚丙烯-聚乙烯嵌段共聚物或嵌段共聚物)。结果表明,在嵌段共聚物中含有一定量的、能为正庚烷抽提出来的乙丙无规共聚物(EPR);分段共聚的产物并非预想的PP-b-PE两嵌段共聚物,而是含有多种组分的共混物;形态表征的结果表明了嵌段共聚物为多相体系,EPR和PE形成分散相以球形无规分布于PP基体中。  相似文献   

7.
用Monte Carlo方法对两嵌段共聚高分子在固液界面的吸附进行模拟,获得了固液界面区吸附链节的分布和吸附构型大小分布等微观信息。考察了吸附性链节的吸附能εAa和两嵌段共聚高分子中吸附性链节比例f对固液界面区高分子链节的分布和各种吸附构型大小的影响。结果表明,吸附层厚度主要由两嵌段共聚高分子中非吸附性链段的长度决定。  相似文献   

8.
碳纤维表面改性研究进展   总被引:2,自引:0,他引:2  
碳纤维因其优异的综合性能常被用作树脂基体的增强材料.然而由于碳纤维与树脂基体之间的界面结合性能较差,其增强的复合材料的力学性能往往与理论值相差甚远,因此必须对碳纤维进行表面改性,以提高其与聚合物基体的界面粘结性能.本文作者综述了国内外关于碳纤维表面改性技术的研究进展,概述了涂层法、氧化法、高能辐射法等改性方法对碳纤维增强复合材料界面强度的改性效果.  相似文献   

9.
<正> 近年出现的用冷等离子体处理填料的方法被认为是偶联剂技术的一个新发展。它是通过等离子体作用,使填料表面产生有利于与基体树脂相容的结构变化,从而实现改善填充体系使用和加工性能的目的。这种处理方法具有作用强度大而穿透力小、效率高,无公害等特点。与采用硅烷、钛酸酯偶联剂等较成熟的处理方法不同,等离子体处理的研究尚在起步阶段,基本局限于对处理效果的探讨,有关处理对填充体系结构影响的研究尚不多见。本文以经乙烯等离子体处理的云母为填料,初步研究了填料与HDPE、IDPE及PS界面的水扩散特性、界面极化特性,以及基体的松弛转变行为。  相似文献   

10.
介绍了PBO(聚对苯撑苯并双噁唑)纤维的结构与性能,并针对该纤维作为复合材料增强体与树脂界面粘结性差的特点,评述了PBO纤维表面改性技术中的化学法、共聚改性、偶联剂处理、等离子处理、电晕处理和辐射处理法的研究进展,并比较了各种方法的改性效果及各自优缺点。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。  相似文献   

16.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

17.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

18.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

19.
袁丽秋 《化学教育》2006,27(5):8-10
面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。  相似文献   

20.
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