聚对苯二甲酸乙二酯微流控芯片的制备和表面改性

高聚物微流控芯片具有制备简单、成本低、可批量生产等突出优点而有望成为一次性器件,近年来在国内外引起了同行们的兴趣.但是,高聚物表面的憎水性、对有机分子的强吸附性、电渗流的不稳定性等又成为高聚物芯片在微流控分析领域得以广泛应用的障碍.表面改性是改善高聚物芯片分析特性的有效途径.     

聚对苯二甲酸丁二酯/聚对苯二甲酸乙二酯固态缩聚的研究

研究了聚对苯二甲酸丁二酯(PBT)/聚对苯二甲酸乙二酯(PET)共混物的固态缩聚反应,从反应动力学过程的测定结果,表明与纯PET或PBT不同,其反应速度较快,并呈超加和的相对分子质量(以特性粘数[η]表征)增长。从反应发生在液相的基本观点出发,说明温度、共混等使液相增多,将加速反应的进行,加上共混物之间的相互缩聚和酯交换,生成嵌段共聚物的结果,导致超加和效应。     

聚对苯二甲酸乙二酯形态结构的光散射研究

在不同结晶条件下,聚对苯二甲酸乙二酯样品出现了三种不同的光散射图形(正常球晶、异常球晶和混合球晶散射图形)。并假定正常球晶的光轴方向与半径垂直;异常球晶的光轴方向与半径夹+45°角或-45°角;混合球晶则是正常球晶与异常球晶叠加的结果。基于这些假定,按照Clough的计算公式,用二维球晶模型分别对具有上述各种光轴取向的球晶进行了计算。结果表明,计算出的H_v、V_v散射图形与实验所得的散射图形符合得很好。偏光显微镜的观察结果也进一步证实了这些模型的假定。     

聚对苯二甲酸乙二酯的热降解和热氧化降解

阐明了聚对苯二甲酸乙二酯缩聚过程中热降解与羧基含量的关系.发现,钛酸四丁酯或草酸亚锡作为缩聚催化剂时,在整个高真空阶段羧基含量并不是一直增加的.采用三种方法(TGA、[η]和COOH)求热氧化降解速度常数,并对其结果进行了讨论.探讨了单一或复合稳定剂和缩聚催化剂对热氧化降解的影响.     

用光干涉法研究聚对苯二甲酸乙二酯非晶态薄膜的吸水性

<正> 高分子材料的吸水性已有很多研究,这是因为在它们的制造加工过程中,以及在用作防护涂层、薄膜和纤维时,尤其对强吸水性材料,吸水率是表征其性能的重要参数之一,具有很大的实际重要性。吸水率通常是用重量法、容量法和浮力法等基于吸水前后的重量变化的直接方法和通过红外吸收光谱、介电性质、NMR和DSC等间接方法测定的,最近有人提出了一种弯曲-悬臂法研究高分子材料的吸湿溶胀特性的新方法。     

聚对苯二甲酸乙二酯溶剂诱导结晶研究 Ⅲ．溶剂对聚对苯二甲酸乙二酯玻璃化转变温度的影响

应用动态力学方法测定了聚对苯二甲酸乙二酯ＰＥＴ／溶剂体系的粘弹谱，从实验上证实溶剂对ＰＥＴ进行增塑，使其玻璃化转变温度降低，导致ＰＥＴ在低于通常的结晶温度下结晶，甚至在室温便进行结晶，证明溶剂诱导结晶是由于玻璃化转变温度降低的机理是正确的，可接受的．     

非晶聚对苯二甲酸乙二酯的制备与表征

采用引入U-polymer的路线制备了非晶聚对苯二甲酸乙二酯(APET).用DSC和DMA等手段研究了APET的性能.结果表明,经改性后得到的APET无结晶,透明性得到改善,玻璃化转变温度和储能模量都较PET有一定程度提高.     

聚对苯二甲酸乙二酯光学特性的椭圆偏振光谱研究

概要介绍椭圆偏振光谱 (SE)的原理与特点 ,并用椭偏光谱测定了一组结晶度不同的无取向PET薄膜的光学常数谱 ,研究半结晶性高聚物PET不同结晶形态对其光学性能的影响 ,发现随结晶度的增加 ,其光学常数显著增大 ,并趋于晶态的光学常数 .光学性质的改变可能与微晶的尺寸有关     

取向非晶态聚对苯二甲酸乙二酯(PET)膜的结晶

采用小角和广角X-散射法比较了未拉和热拉PET膜在结晶性能方面的差别,热拉试样在分子链段的小尺度范围内基本上是无规取向,而在分子链的大尺度范围内却是高度取向的。研究结果表明:热拉PET膜的结晶诱导期较短,长周期发展得较快,结晶后小角X-线散射表现出明显的各向异性,在热处理过程中先出现显著的热收缩,随后又表现出结晶伸长现象,这些都和未拉试样有明显的差别。     

聚对苯二甲酸乙二酯/聚苯磷酸二苯砜酯体系的性能研究

混合热计算和FTIR分析表明，聚对苯二甲酸乙二酯（PET）与聚苯膦酸二苯砜酯（PSPPP）具有一定的相容性．不同PSPPP含量的PET均具有较高的热稳定性，PET／PSPPP体系的阻燃性随阻燃剂PSPPP含量的增加而提高，PSPPP重量百分含量为5％（下同）的阻燃PET体系的LOI值可达到30．1．由不同分子量的PSPPP构成的各种配比的PET体系，其表现粘度随切变速率的增大而降低，PSPPP的分子量较低的阻燃体系比分子量较高的体系具有更低的粘度，其差值随温度的升高而增大．     

疏水性聚丙烯酸酯人工晶状体的低温等离子体改性

通过低温等离子体表面改性技术对疏水性聚丙烯酸酯人工晶状体进行表面改性, 并对改性前后材料的表面结构、形貌和光学性能进行了表征. 静态水接触角结果显示, 经过氨等离子体处理后的人工晶状体亲水性效果最好, 同时最佳的改性时间为120 s, 改性功率为150 W. XPS分析结果进一步证实, 经等离子体处理后, 在人工晶状体表面引入了极性基团. 原子显微镜观察结果显示, 改性后材料表面更加凹凸不平, 粗糙度显著增加而透光率变化很小, 但过大功率改性的样品透光率明显下降. 时效性测试结果表明, 人工晶状体在改性14 d后疏水性恢复趋于稳定.     

微波等离子体对聚乙烯材料的表面改性

对高分子材料进行表面修饰,可以赋予材料表面新的物理和化学性能,提高材料的亲水性、粘结性、电镀和生物匹配性等．在表面改性方法中,新近发展的等离子体改性技术由于具有操作简单,工艺干法化,不影响材料本体结构和性能等优点而日益受到人们的重视［１,２］．微波等...     

Plasma Surface Modification of Fluoropolymers Studied by ToF-SIMS

Surface modification by plasma treatment is an efficient way of improving metal adhesion to polymers. Here, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is used to characterize the surfaces of Teflon PFA and Teflon AF1600 films, following plasma treatments in H₂, O₂ and N₂ gases. This work is complementary to our previous study using XPS, and is particularly directed toward the identification of incorporated hydrocarbons which could seriously affect metal adhesion. Plasma treatments strongly modify the surfaces of fluoropolymers, causing the ablation of a part of the fluorocarbon structure, with H₂ being the most effective gas. The hydrocarbon content of such surfaces is not negligible, and a comparison with hydrocarbon levels on untreated surfaces suggests that a substantial fraction of this material was incorporated on plasma treatment; this is particularly so in the case of H₂ plasma treatment. Due to expected strong matrix effects caused by significant changes in surface chemistry and structure following the various plasma treatments, the use of SIMS absolute intensity values is discussed in terms of data treatment artifacts. Moreover, due to the differences in secondary ion yields between characteristic hydrocarbon and fluorocarbon SIMS peaks, the use of peaks normalized to the total intensity is also impractical. Here, positive mode absolute intensities and negative mode peak intensity values, when normalized to I_tot - I(H^–) - I(F^–), give valuable information, as in the comparison of hydrocarbon and N incorporations.     

Surface Modification of Vapor-grown Carbon Nanofibers in Radio Frequency Plasma

"Vapor-grown carbon nanofibers (VGCNFs) were treated in radio frequency (RF) plasma to activate their surface and thus to improve the compatibility with the matrix in polymer composites. The surface of VGCNFs was modified in atmospheres containing different ratios of O2 and Ar. Fourier transform infrared spectroscopy and thermogravimetric measurement shows that when the O2 content in mixture gases was 5%, C-O and O-H functional groups were produced abundantly in the surface of the VGCNFs. When O2 content increased to 8%, most of the surface of carbon fibers was severely oxidized, resulting in defects in structures of the inner layers of VGCNFs."     

NafionTM膜表面改性用等离子体聚合方法提高膜的阳离子选择性

采用辉光放电等离子体聚合方法 ,以 C2 H4 和 NH3 为单体 ,在 Nafion TM膜表面沉积一层含氨基及酰氨基的类聚乙烯阴离子交换膜 ,提高了 Nafion TM膜对阳离子的选择性 ,同时不显著增加膜电阻 .由 SEM确定该等离子体聚合膜厚约 0 .5μm,用红外光谱及 X光电子能谱表征膜结构 .采用四电极法测量膜电阻 ,膜对质子的选择性由 Cu2 + 的迁移数 t Cu表征 ,用二室隔膜装置 (0 .2 5mol/L Cu Cl2 -0 .5mol/L HCl|等离子体处理膜 |1 mol/L HCl)测量 t Cu. O2 等离子体预处理 Nafion TM膜有利于沉积膜在 Nafion TM膜上的沉积并与 Nafion TM膜紧密结合 .经改性后的 Nafion TM膜电阻值仍然很小 ,在 1 mol/L HCl溶液中电阻小于 0 .5Ω· cm2     

辉光放电等离子体对聚丙烯纤维的表面改性

在对电晕、介质阻挡放电、γ射线辐射接枝对化纤改性的简要介绍基础上，重点论述了辉光放电等离子体对聚丙烯纤维的改性。并按等离子体技术的发展过程，对低压和常压辉光放电等离子体对聚丙烯纤维与织物改性的特点、原理及发展前景进行了扼要综述，指出常压辉光放电等离子体是一种很有潜力的表面改性技术。     

Surface Modification of Nitrile Rubber by Plasma Polymerization

Radio frequency plasma polymerization of vinylidene fluoride was used to modify the surface properties of nitrile rubber. The chemistry and frictional properties of the plasma films were characterized. FTIR transmission spectra and EDX analysis of plasma polymer films deposited on NaCl windows showed that the degree of fluorination of the plasma polymers increased as plasma power was increased from 25 to 50 W, and then decreased monotonically at higher powers. An estimation of the actual F/C ratio from EDX data indicated that the plasma polymer films contained approximately one fluorine atom for every 2–5 carbon atoms. Sliding friction tests on a Delrin countersurface showed that the coefficient of friction of the plasma treated rubbers was lower than untreated rubber, but slighly higher than rubber coated with silicone oil. Repetitive sliding friction testing showed that silicone oil treated samples had a longer lubricating lifetime than plasma treated samples. However, cyclic friction tests conducted with nitrile rubber o-rings yielded similar frictional behavior and lubricating lifetimes for silicone oil and plasma treatments. There was no correlation between chemical composition and the frictional and wear properties of the plasma films. Environmental scanning electron micrographs showed that the plasma films were brittle and tended to crack and flake off during wear testing.     

Two Atmospheric-pressure Plasma Sources for Polymer Surface Modification

Two atmospheric-pressure plasma sources were studied. One was a helium plasma generated by a RF discharge, and the other was an air plasma generated by a dielectric barrier discharge (DBD). The two plasma sources were characterized on electron density, emission spectrum, and ozone density. The modification of polyethyleneterephthalate (PET) surfaces by the two plasmas was investigated. PET strips were exposed to the plasma at the exit of the plasma source. Water contact angles were measured for surfaces modified with different processing parameters. The change in contact angles was monitored as a function of time. Modification mechanisms were also investigated.     

高强聚乙烯纤维的冷等离子体改进

高强聚乙烯纤维的冷等离子体改进金士九，倪亦斌，张佐光（中国科学院化学研究所北京１０００８０）（北京航空航天大学北京）关键词　高强聚乙烯纤维，等离子体，表面改性，界面性能由高强聚乙烯纤维制成的复合材料抗高速撞击（抗弹）性能远远优于芳纶纤维，广泛用作各种...     

二甲基甲酰胺在聚乙烯膜表面的等离子体聚合

通过二甲基甲酰胺的等离子体聚合作用，对聚乙烯膜进行表面改性。研究了等离子体工艺参数对聚合物膜沉积速度的影响，用ＦＴＩＲ、ＸＰＳ分析了聚合物膜的组成结构，测定了改性聚乙烯膜的接触角和表面。