二苯醚—对苯二甲酰氯—4,4‘—二苯氧基二苯砜三元共聚物的合成与性能

以无水ＡｌＣｌ３／ＣｌＣＨ２ＣＨ２Ｃｌ／ＮＭＰ为催化剂／溶剂体系，通过缩聚反应，由二苯醚，对苯二甲酰氯和４，４－二苯氧基二苯砜合成了聚醚酮酮和聚醚砜醚酮酮共聚物（ＰＥＫＫ／ＰＥＳＥＫＫ）．考察了单体浓度、反应时间对聚合物分子量的影响，并对其进行了ＩＲ、ＤＳＣ、ＷＡＸＤ等分析表征．结果表明，共聚物具有优异的耐热性，随着共聚物中ＰＥＳＥＫＫ单元含量的增加，其玻璃化温度逐渐升高，而熔融温度和结晶度逐渐降低．与聚醚酮酮（ＰＥＫＫ）相比，共聚物的断裂伸长率明显提高，而拉伸强度和拉伸模量却有所下降，但仍具有良好的力学性能．     

新型间位聚醚酮醚酮酮的合成与结晶

聚醚醚酮(ＰＥＥＫ)自八十年代初由英国ＩＣＩ公司开发并工业化以来,由于其优异的性能已在机械、航天等领域得到广泛应用.但ＰＥＥＫ的Ｔｇ只有143℃,影响了使用范围.因此其它聚芳醚酮类聚合物相继被开发出来.但这些聚芳醚酮的主链结构大都为全对位连接,使其熔点较高以至加工难度增大.因此,高Ｔｇ和低Ｔｍ的聚芳醚酮的合成是一项很有意义的工作.如果在聚合物的主链结构中引入间位结构,则可在对Ｔｇ影响较小的情况下降低熔点来改善加工条件[1,2].新型间位聚醚酮醚酮酮(ＰＥＫＥＫＫ(Ｔ/Ｉ))也是其中一种.本文主要研究ＰＥＫＥＫＫ(Ｔ/Ｉ)的合…     

PPEKK/PEI共混物的相容性及拉伸性能

作为相容体系 ,聚芳醚酮与聚醚酰亚胺 (ＰＥＩ)共混物体系的研究受到了研究者的重视[1～ 4] .由于现在已商品化的聚芳醚酮基本上都是半结晶型聚合物 ,所以有有关无定型聚芳醚酮与聚醚酰亚胺共混物的研究鲜见报道 .含二氮杂萘酮结构聚芳醚酮酮 (ＰＰＥＫＫ)是一种新型耐高温聚合物 ,相比于已经商品化的各种聚芳醚酮 ,ＰＰＥＫＫ除具有优异的综合性能外 ,它最大的特点表现在以下两方面 ,ＰＰＥＫＫ耐热性突出 ,玻璃化转变温度 (Ｔｇ)为 2 4 5℃左右 ,远高于各种商品化的聚芳醚酮 ;ＰＰＥＫＫ为无定型聚合物 ,易溶于多种有机极性溶剂 ,大大的扩…     

酞侧基聚芳醚砜和聚芳醚酮共混物的高温流变行为

用锥板粘度计测试了酞侧基聚芳醚砜（ＰＥＳ－Ｃ）和酞侧基聚芳醚酮（ＰＥＫ－Ｃ）及其共混物的熔体流变行为．试样的流动活化能分别为１４５、１３３和１１２ＫＪ／ｍｏｌ．共混物的熔体粘度显著低于ＰＥＳ－Ｃ和ＰＥＫ－Ｃ粘度的对数加和值．并证明试样的熔体流动性和加工稳定性都已达到注射成型工艺的要求．     

Williamson法合成两亲性聚醚砜酮-聚乙二醇接枝共聚物

含二氮杂萘酮结构的聚醚砜酮(PPESK)是一种新型的耐热可溶解工程塑料,其玻璃化温度高达263~305℃,可用来制造耐高温气体分离、超滤和纳滤膜,表现出优异的综合性能[1~4].然而,膜材料本身的疏水特性使PPESK膜在过滤操作中易遭受膜污染,导致膜性能下降,对膜材料进行亲水化改性以抑     

含间位取代苯基聚醚酮酮的结晶与晶体结构研究

通过差示扫描法（ＤＳＣ）及广角Ｘ 射线衍射（ＷＡＸＤ）技术研究了含间位取代苯基聚醚酮酮（ＰＥＫｍＫ）的结晶行为与晶体结构．Ｘ 射线结果表明，从熔融态及玻璃态结晶时，ＰＥＫｍＫ只有一种晶型，其晶胞参数为：ａ＝０７６７２ｎｍ，ｂ＝０６１４９ｎｍ，ｃ＝１５９９ｎｍ．ＤＳＣ结果表明，ＰＥＫｍＫ热分析曲线都出现了熔融双峰，低熔融峰（ＤＯＷｎ）热焓占总热焓４～７％，它源于初始结晶形成的同一晶型不同厚度片晶．低熔融峰在２５０℃以上结晶转化成高熔融峰（Ｉ），ＰＥＫｍＫ平衡熔点为２９５℃     

含磺酸钠基的杂萘联苯聚芳醚砜酮的合成与表征

对4,4'-二氯二苯砜进行磺化改性制得磺化二氯二苯砜,不同比例的4,4'-二氯二苯砜和磺化二氯二苯砜与含二氮杂萘酮结构的类双酚单体(DHPZ)及4,4'-二氟二苯酮共聚合制得不同磺化度的磺化聚醚砜酮.对磺化单体及聚合物进行了IR和¹HNMR表征,并研究了聚合物的溶解性和成膜性能.     

几种热塑性特种工程塑料的热分析研究

聚芳醚和聚芳硫醚两类聚合物都为热塑性的耐高温特种高分子材料 ,由于它们的加工性好、加工成型效率高 ,受到了世界各国的高度重视。这两类聚合物在结构上有许多相似之处 ,如它们的主链都含苯环、酮基或砜基 ,而聚芳醚类聚合物的柔性基团为醚键 ,聚芳硫醚类聚合物的柔性基团为硫醚键 ,但由于氧和硫在元素周期表中属于同一族元素 ,原子结构仍然相似 ,因而在某些方面具有一定的可比性。研究它们的性能差异对于改进聚合物性能以及进行进一步的结构设计将有一定的帮助。在这两类聚合物中 ,国内已商品化生产的品种有ＰＥＥＫ、ＰＥＳ和ＰＰＳ ,有…     

稀土元素与NEB二元配合物的pH电位法分析

氨三乙氧基三苯甲酸(ＮＥＢ)(ＮＥＢ·ＨＣｌ的分子结构式见下图)作为有立体选择性的配体,它与铀酰离子ＵＯ2(Ⅱ)配位作用已有报导[1]。在对ＮＥＢ质子化常数及二元体系Ｍ(Ⅱ)-ＮＥＢ·ＨＣｌ(Ｍ=Ｃｄ、Ｃｏ、Ｎｉ、Ｃｕ和Ｚｎ)配合物的稳定常数测定的基础上[2],本文在25℃及离子强度为0 2ｍｏｌ/ＬＫＮＯ3的条件下,用精密ｐＨ电位法考察二元体系ＲＥ(ＩＩＩ)—ＮＥＢ(ＲＥ=Ｌａ→Ｎｄ,Ｓｍ→Ｌｕ,Ｙ)中存在的配合物物种及其稳定常数。ＮＥＢ·ＨＣｌ结构式1　实验部分1 1　试剂和仪器ＮＥＢ·ＨＣｌ(Ｈ3Ｌ·ＨＣｌ,Ｌ3-=Ｃ27Ｈ24ＮＯ9)…     

聚乙二醇-聚二氧六环酮嵌段共聚物的合成及表征

用辛酸亚锡［Ｓｎ（Ｏｃｔ）２］作催化剂，进行了端羟基聚乙二醇（ＰＥＧ）和１，４ 二氧六环酮（ＤＯＮ）的共聚反应，得到嵌段共聚物ＰＤＯＮ ｂ ＰＥＧ ｂ ＰＤＯＮ．根据１Ｈ ＮＭＲ谱图计算结果表明共聚物组成随两组分投料比而改变．共聚物的ＤＳＣ结果表明嵌段共聚物中ＰＤＯＮ的熔点和结晶度的变化相对较小，而ＰＥＧ的熔点及结晶度均有较大降低．将ＰＥＧ引入可大大提高材料的吸水率．     

连续纤维增强含二氮杂萘酮联苯结构聚芳醚砜酮树脂基复合材料的界面

利用射频感性耦合冷等离子体(ICP)处理技术改性连续纤维表面,分别采用X射线光电子能谱(XPS)、原子力显微镜(AFM)及动态接触角分析(DCA)系统研究了等离子体处理时间、放电气压、放电功率等工艺参数对连续碳纤维、芳纶纤维和对亚苯基苯并二噁唑(PBO)纤维的表面化学成分、表面形貌、表面粗糙度及表面自由能的影响.研究结...     

Improvement of PBO fiber surface and PBO/PPESK composite interface properties with air DBD plasma treatment

The interface of fibrous composites is a key factor to the whole properties of the composites. In this study, the effects of air dielectric barrier discharge (DBD) plasma discharge power density on surface properties of poly(p‐phenylene benzobisoxazole) (PBO) fiber and the interfacial adhesion of PBO fiber reinforced poly(phthalazinone ether sulfone ketone) (PPESK) composite were investigated by several characterization methods, including XPS, SEM, signal fiber tensile strength, interlaminar shear strength, and water absorption. After the air DBD plasma treatment at a power density of 41.4 W/cm³, XPS analysis showed that some polar functional groups were introduced on the PBO fiber surface, especially the emergence of a new oxygen‐containing group (?O–C = O group). SEM observations revealed that the air DBD plasma treatment had a great influence on surface morphologies of the PBO fiber, while the signal fiber tensile strength results showed only a small decline of 5.9% for the plasma‐treated fiber. Meanwhile, interlaminar shear strength value of PBO/PPESK composite was increased to 44.71 MPa by 34.5% and water absorption of the composite decreased from 0.46% for the untreated specimen to 0.27%. The results showed that the air DBD plasma treatment can effectively improve the properties of the PBO fiber surface and the PBO/PPESK composite interface. Results obtained from the above analyses also showed that both the fiber surface and the composite interface performance would be reduced when an undue plasma discharge power density was applied. Copyright © 2011 John Wiley & Sons, Ltd.     

Plasma Treatment of Glass Surfaces Using Diffuse Coplanar Surface Barrier Discharge in Ambient Air

We report a study on the treatment of flat glass surfaces by ambient air atmospheric pressure plasma, generated by a dielectric barrier discharge of coplanar arrangement of the electrode system—the diffuse coplanar surface barrier discharge (DCSBD). The plasma treatment of glass was performed in both static and dynamic modes. With respect to wettability of the glass surface, treatment in static mode resulted in non-uniform surface properties, whereas dynamic mode provided a fully uniform treatment. A water contact angle measurement was used to determine the efficiency of plasma treatments in dynamic mode and also to investigate a hydrophobic recovery of plasma treated glass surfaces. The X-ray photoelectron spectroscopy measurements showed a decrease of overall carbon concentrations after plasma treatment. A deconvolution of C1s peak, showed that a short plasma treatment led to decrease of C–C bonds concentration and increases of C–O and O–C=O bond concentrations. An enhancing influence of the glass surface itself on DCSBD diffuse plasma was observed and explained by different discharge onsets and changes in the electric field distribution.     

Tailoring wettability change on aligned and patterned carbon nanotube films for selective assembly

The effects of oxygen reactive ion etching (RIE) on the surface wettability of aligned carbon nanotube (CNT) films have been systematically investigated. It was found that 3 s of RIE treatment could change the surface of CNT films from hydrophobic to more hydrophilic. The degree of modification in the surface wettability of the film could be controlled by the flow rate of O2 gas during the RIE process. It is proposed that such a surface hydrophobicity change is related to the opened structure and functionalized tip of as-treated CNTs by oxygen reactive ions. More importantly, after the RIE treatment, focused laser pruning was utilized to trim the surface layer of treated CNTs and revert them back to a hydrophobic surface. Combined with the laser pruning technique and O2 RIE treatment, CNT templates with interlaced wettability surfaces in a stripe pattern have been fabricated. It has been demonstrated that this interlaced and structured wettability pattern can be used to selectively assemble microspheres or quantum dots on the aligned CNT films with desired patterns.     

Surface modification of plasma‐pretreated expanded poly (tetrafluroethylene) films by graft copolymerization

A two‐step process based on a low‐pressure helium plasma treatment followed by acrylic acid‐grafting copolymerization was used for the surface modification of expanded polytetrafluoroethylene (ePTFE) films. The effects of plasma treatment power and treatment time on the hydrophilicity of the film surface were investigated. The wettability of the ePTFE film surface was characterized by water contact angle, and the surface compositions of the untreated and treated ePTFE samples were evaluated by atomic force microscopy and XPS. Contact angle measurements revealed that the hydrophilicity of the ePTFE film surface was greatly enhanced by the combined actions of the plasma treatment and acrylic acid grafting, and the contact angle decreased from 145° to 66°. Atomic force microscopy analyses showed that the surface roughness increased after the plasma treatment. XPS analyses showed substantial increase in the concentration of carbon and oxygen atoms and a decrease in the concentration of fluorine atoms at the film surface. T‐peel strength showed an improved bonding strength between the film and an adhesive tape after the treatment. Copyright © 2012 John Wiley & Sons, Ltd.     

Modification of Polyimide in Barrier Discharge Air-Plasmas: Chemical and Morphological Effects

Chemical and physical modifications of polyimide (PI) surfaces caused by an air plasma have been studied. The plasma-induced surface changes of PI were investigated by using a local dielectric barrier discharge (DBD) in air at atmospheric pressure and room temperature as a function of the plasma exposure time and plasma power, while the excitation frequency was kept constant at about 130 kHz. The first results obtained in this work suggest that DBDs operating in air at atmospheric pressure can be an efficient alternative plasma source for surface treatment of polymers: a short time air plasma treatment of few seconds leads to chemical and physical changes including the rise of wettability, surface oxidation, and enhancement of surface roughness. Therefore, this simple kind of dry surface treatment seems to be an effective, low cost method for production of well-adhering subsequent layers such as metal films, paints, glues, etc. on DBD pretreated polymers.     

GRAFT COPOLYMERIZATION OF ACRYLAMIDE ONTO POLYPROPYLENE FILMS BY PLASMA TECHNIQUE

The graft copolymerization of acrylamide onto polypropylene (PP) Film was carried out by using a capacitively coupled rf plasma apparatus with external plate electrodes. The relationship between the surface structure of the Ar plasma-treated PP films and the extent of grafting of acrylamide on the films was studied through observing the effects of discharge power and exposure time on the relative content of free-radical on the film surface. Meanwhile, the wettability and surface energy of the PP film were measured.     

Improvement of interfacial adhesion for plasma‐treated aramid fiber‐reinforced poly(phthalazinone ether sulfone ketone) composite and fiber surface aging effects

Interfacial adhesion between the fiber and the matrix in a composite is a primary factor for stress transfer from the matrix to the fiber. In this study, oxygen plasma treatment method was applied to modify the fiber surface for improving interfacial adhesion of aramid fiber‐reinforced poly(phthalazinone ether sulfone ketone) (PPESK) composite. Composite interfacial adhesion properties were determined by interlaminar shear strength (ILSS) using a short‐beam bending test. The composite interfacial adhesion mechanism was discussed by SEM. The changes of chemical composition and wettability for plasma‐treated fiber surfaces stored in air as long as 10 days were investigated by XPS and dynamic contact angle analysis (DCAA), respectively. Results indicated that oxygen plasma treatment was an effective method for improving interfacial adhesion; plasma‐treated fiber surface suffered aging effects during storage in air. Copyright © 2008 John Wiley & Sons, Ltd.     

Enhancement of wettability in low density polyethylene films using low pressure glow discharge N2 plasma

Low pressure glow discharge nitrogen plasma has been used to improve wettability in a low density polyethylene (LDPE) film for technical applications. The plasma treatment was carried out at a power of 300 W for different exposure times in the 1–20 min range. Wettability changes were analyzed using contact angle measurements. In addition to this, plasma‐treated samples were subjected to an aging process to determine the durability of the plasma treatment. X‐ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy were used for surface characterization. The nitrogen plasma treatment considerably reduced contact angle values thus indicating an increase in surface wettability. The spectroscopic study showed presence of oxygen‐based species on the plasma‐treated samples, which are mainly generated after the plasma treatment as a consequence of air exposure. These polar species contribute to improve surface functionalization, but this is almost lost during aging due to the hydrophobic recovery process. Microscopic studies revealed that also small changes in surface roughness occurred during the plasma treatment but these are very low compared to surface activation. The results confirmed that low pressure nitrogen can be considered as an environmentally efficient process to improve wettability in low density polyethylene films. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2390–2399, 2007     

The effect of surface wettability on induction and growth of neurites from the PC-12 cell on a polymer surface

Surface properties of polymeric devices that are used to regenerate nervous damage are a point to be considered for axon regeneration in nerve system. In our previous studies, we prepared a wettability gradient on polyethylene (PE) surfaces using a corona discharge treatment from a knife-type electrode whose power increases gradually along the sample length. The PE surfaces were oxidized gradually with increasing power. The effect of surface wettability on the different types of cells has an important role for cell adhesion and proliferation. The purpose of this study is to investigate neurite formation on polymer surfaces with different wettability. Induction and growth of neurites from the rat pheochromocytoma (PC-12) cells attached on the polymer surfaces with different hydrophilicity were investigated using the wettability gradient PE surfaces prepared by a corona discharge treatment. Neurites were investigated for number and length of neurites in terms of surface wettability. It was observed that neurite formation of PC-12 cells was increased more onto the positions with moderate hydrophilicity of the wettability gradient surface than onto the more hydrophobic or hydrophilic positions. From those results, it could be assumed that initial adhesion of PC-12 cells was caused by more calf serum (CS) protein than nerve growth factor (NGF), whereas the neurite formation of PC-12 cells was caused by more NGF than CS protein. It follows from what has been said thus far that PC-12 cells are a differentiated neuronal phenotype with a long neurite at around the position 2.5 cm (water contact angle of about 55 deg). In conclusion, surface wettability plays an important role for neurite formation on the polymer surfaces for axon regeneration.