电子束辐射接枝丙烯酸改性聚四氟乙烯

采用电子束辐射接枝工艺,在保持本体强度的前提下实现了对聚四氟乙烯(PTFE)板材的表面丙烯酸接枝改性。傅里叶变换红外扫描测试表明丙烯酸成功接枝到PTFE板材表面。通过单因素分析法研究了辐射接枝工艺参数对接枝量的影响,并择优选出最佳的辐射接枝工艺条件:吸收剂量为18 kGy,丙烯酸浓度为60%,反应温度为70℃。表面接触角测试表明,接枝改性后PTFE板材表面浸润性较改性前大幅提高,水接触角由120°下降到60°。黏接性能测试结果表明,辐射接枝改性可显著提高PTFE的黏接强度,达到23 N/cm~2。     

羊毛辐射接枝甲基丙烯酸缩水甘油脂研究

对甲醇溶液中甲基丙烯酸缩水甘油脂在羊毛纤维上的γ射线辐射接枝反应作了系统研究。考察了气氛、剂量、剂量率、单体浓度等实验条件对接枝反应的影响，发现气氛对接枝反应的影响很小，而接枝率随辐照剂量和单体浓度的增大而提高，接枝效率则随单体浓度的增大而减小。在剂量大于11kGy后接枝率达到平稳状态。用红外吸收谱仪(IR)和扫描电镜(SEM)分析发现单体均匀地接枝在羊毛上。     

微粒聚四氟乙烯-苯乙烯辐射接枝物的红外光谱定量测定法

本文叙述粉末状材料辐射接枝工艺中测定接枝单体含量的红外光谱方法。在粉末聚四氟乙烯—苯乙烯接枝体系中使用同种材料制备具有不同接枝率的薄膜作为标准物质,选择1493cm~(-1)和2362cm~(-1)谱带作为组分的分析谱带,利用最小二乘法计算了二谱带的吸光度比对接枝率(g)的回归方程。此方法对难以称量求得接枝率的微粒接枝共聚物的定量测定具有准确、方便的优点。     

氧化镁辐射接枝烯类单体的研究

本文研究了氧化镁辐射接枝苯乙烯及甲基丙烯酸甲酯。用红外光谱、X线衍射、裂解色谱等方法表征接技反应结果表明,MgO-g-MMA接技共聚物与MgO-PMMA共混物,在1380cm~(-1),1430～1480cm~(-1)处有不同的红外吸收峰,而且MgO-g-MMA接技共聚物在裂解色谱图上出现明显的4号峰,在X线衍射图上出现MgO的五个晶相峰外还出现另外五个晶相峰,它们的晶面间距分别为4.7702A、2.3618A、1.7926A、1.5703A、1.3084A,这说明由于MgO晶格影响MMA聚合生成某些规整的聚合物。证明辐射接枝聚合物是以化学键联结在无机物上的,而不是无机物和均聚物的混合物。接枝共聚物的分子量要比均聚物的分子量大,但分子量分布则较宽。辐射接枝后氧化镁和聚乙烯的亲和力有所增加。     

预辐射接枝法制备FEP-g-PSSA/AA膜

采用γ射线预辐射接枝方法制备了FEP—g—PSSA／AA膜，反应制得的接枝膜是一种含氟磺酸型质子交换膜。系统研究了影响接枝反应的阻聚剂用量、膜的厚度、单体摩尔比及总摩尔浓度变化等因素。结果表明，丙烯酸（Acrylic acid，AA）与苯乙烯磺酸钠（Sodium styrene sulfonate，SSS）对全氟乙丙烯（Polytetranuoroethyleneco-hexanuoropropylene，FEP）的接枝率几乎不受膜厚度变化的影响，而且全氟乙丙烯（FEP）辐照后放置三个月再进行接枝反应，接枝率也几乎没有变化。     

预辐射聚丙烯纤维接枝苯乙烯的研究

采用预辐射接枝法，对聚丙烯纤维分别采用电子束和＾６０Ｃｏγ射线在空气和氮气氛下进行辐照，然后将样品置于苯乙烯－甲醇溶液体系中进行接枝反应。研究了吸收剂量、反应温度、反应时间、苯乙烯浓度等对接枝率的影响以及预辐照样品的存放时间，存放条件等对接枝率的影响，并比较了两种不同辐射源在预辐射接枝中的差别。     

聚四氟乙烯-苯乙烯-反丁烯二酸辐射接枝共聚合—表面结构和粘结性能的关系

本文用偏光显微镜和扫描电子显微镜研究了聚四氟乙烯—苯乙烯—反丁烯二酸接枝共聚物的表面和断面结构。在实验温度19～40℃范围内,辐照剂量率高于临界辐照剂量率,接枝发生在薄膜表面,反之低于临界辐照剂量率,接枝在薄膜整体内进行。在表面接枝的条件下,接枝共聚物表面形成大大小小有规则的球状结构。接枝的表面层是由聚四氟乙烯—苯乙烯—反丁烯二酸接枝共聚物的内层和苯乙烯—反丁烯二酸均聚物的外层所组成,它们之间以化学键相联。粘结性能的主要贡献是外层。根据单体的扩散和渗透讨论了接枝过程和机理,及其对表面结构的影响。凡为表面接枝,其粘结强度均大于100kg/cm~2,反之整体接枝的粘结强度均好40kg/cm~2以下。     

棉纤维素预辐射接枝苯乙烯的研究

研究了棉纤维素预辐射接枝苯乙烯的接枝率与辐射剂量、剂量率，接枝反应时间，反应温度的关系，以及它们的数学表达式，并由此计算出反应的活化能。对此类预辐射接枝反应动力学研究做了初步分析。     

Variations in surface and electrical properties of polytetrafluoroethylene film after plasma-induced grafting of acrylic acid

Polytetrafluoroethylene(PTFE) film was graftpolymerized with acrylic acid(AAc) via a low-temperature plasma technique.The effect of plasma treatment parameters(radio-frequency power and treatment time) on the spin number of free radicals in PTFE film was examined.Attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy,X-ray photoelectron spectroscopy,scanning electron microscopy,and atomic force microscopy were employed to characterize the chemical structure,surface composition,and microstructure of the original PTFE and PTFE-g-PAAc films,respectively,in order to verify the successful graft polymerization of AAc onto a PTFE film surface.Thermogravimetric analysis illustrated that the thermal stability of bulk PTFE film remains unchanged after graft modification.Water contact angle measurements confirmed that the hydrophilicity of PTFE-g-PAAc film was effectively improved as compared to the original PTFE film.The dielectric constant(ε_r) of PTFE-g-PAAc(GD =218 μg/cm~2) film remained invariable,compared to that of the unmodified PTFE film.Nevertheless,the dielectric loss(tanδ) of PTFE film increased considerably,from 0.0002(GD = 0μg/cm~2) to 0.0073(GD = 218 μg/cm~2),which might be due to the increase in surface polarity and moisture resulting from AAc graft modification.In addition,the surface electrical resistance(R_s) of PTFE film decreased slightly,from 131.89(GD = 0 μg/cm~2) to 110.28 Ω cm~2(GD = 218μg/cm~2) after surface modification,but still retained its inherent high impedance.     

低温等离子体接枝改性聚四氟乙烯薄膜表面无钯化学镀铜

通过低温等离子体接枝改性方法将丙烯酸(Acrylic acid,AAc)接枝聚合于聚四氟乙烯(Polytetrafluoroethylene,PTFE)薄膜表面,随后进行无钯化学镀铜,制备出表面镀铜的PTFE薄膜(PTFE-g-PAAc-Cu)。衰减全反射傅里叶变换红外光谱(ATR-FTIR)测试结果表明,丙烯酸成功地接枝于PTFE薄膜表面;通过扫描电镜(Scanning electron microscopy,SEM)和原子力显微镜(Atomic force microscopy,AFM)观察发现,镀铜均匀沉积于PTFE薄膜表面;3M胶带粘贴方法(ASTM D3359标准)评估结果表明,铜层与PTFE薄膜粘结牢固,3M胶带未能够将铜层与PTFE薄膜分离开;电性能测试结果表明,PTFE-g-PAAc-Cu的表面电阻(Rs)降至1.27′10~(-2)Ω/sq,电阻率降至50.1μΩ?cm,其导电性由绝缘体提高到导体水平(导体的电阻率范围为1~10~3μΩ?cm),有望在柔性覆铜板领域获得应用。     

PTFE的辐射裂解、交联及其应用

聚四氟乙烯（PTFE）是一种性能优异的工程塑料,通常被认为是典型的辐射裂解材料。PTFE可以在不同条件下实现裂解并生成PTFE微粉。在高于PTFE的熔点即温度为330～340℃,真空或惰性气氛下进行辐照,可实现PTFE的交联。本工作综述了PTFE辐射裂解和交联研究的历史和最新进展,并对交联PTFE在润滑材料、燃料电池、光刻等领域的应用进行了介绍。     

Irradiation effect of carbon negative-ion implantation on polytetrafluoroethylene for controlling cell-adhesion property

We have investigated the irradiation effect of negative-ion implantation on the changes of physical surface property of polytetrafluoroethylene (PTFE) for controlling the adhesion property of stem cells. Carbon negative ions were implanted into PTFE sheets at fluences of 1 × 10¹⁴-1 × 10¹⁶ ions/cm² and energies of 5-20 keV. Wettability and atomic bonding state including the ion-induced functional groups on the modified surfaces were investigated by water contact angle measurement and XPS analysis, respectively. An initial value of water contact angles on PTFE decreased from 104° to 88° with an increase in ion influence to 1 × 10¹⁶ ions/cm², corresponding to the peak shifting of XPS C1s spectra from 292.5 eV to 285 eV with long tail on the left peak-side. The change of peak position was due to decrease of C-F₂ bonds and increase of C-C bonds with the formation of hydrophilic oxygen functional groups of OH and CO bonds after the ion implantation. After culturing rat mesenchymal stem cells (MSC) for 4 days, the cell-adhesion properties on the C⁻-patterned PTFE were observed by fluorescent microscopy with staining the cell nuclei and their actin filament (F-actin). The clear adhesion patterning of MSCs on the PTFE was obtained at energies of 5-10 keV and a fluence of 1 × 10¹⁵ ions/cm². While the sparse patterns and the uncontrollable patterns were found at a low fluence of 3 × 10¹⁴ ions/cm² and a high fluence of 3 × 10¹⁵ ions/cm², respectively. As a result, we could improve the surface wettability of PTFE to control the cell-adhesion property by carbon negative-ion implantation.     

Hydrocarbon proton-conductive membranes prepared by radiation-grafting of styrenesulfonate onto aromatic polyamide films

Novel method for preparing aromatic hydrocarbon proton-conductive membranes without sulfonation and membrane casting process is achieved by radiation-grafting of sodium styrenesulfonate to an aromatic polyamide, poly(m-xylylene adipamide) (Nylon-MXD6) films and subsequent ion-exchange. The styrenesulfonate was easily grafted into the Nylon-MXD6 films from an oxygen-free dimethyl sulfoxide (DMSO) solution at 60 °C. As a result, the resulted styrenesulfonic acid-grafted Nylon-MXD6 films, namely proton-conductive membrane, with high ion-exchange capacity up to 1.63 mmol/g, can be obtained. The membrane was transparent and highly hydrophilic. The proton conductivity, water uptake and methanol permeability of the proton-conductive membranes were investigated with respect to their use in fuel cells. The high proton conductivity reached 0.083 S/cm, comparable to Nafion. Furthermore, the methanol permeability was significantly lower than that of the Nafion membrane. Therefore, the Nylon-MXD6-based proton-conductive membrane is a more promising material for the direct methanol fuel cells (DMFCs).     

聚氟乙烯-苯乙烯共辐照接枝反应的研究

用~(60)Co-γ射线共辐照法作了聚氟乙烯薄膜-苯乙烯的辐射接枝共聚合反应,研究了单体浓度、辐照剂量率、温度及薄膜厚度与接枝共聚反应速度的关系。在实验条件下,接枝共聚反应速度分别与单体浓度、辐照剂量率及薄膜厚度的2.5、0和-1次方相关联。接枝共聚反应的总活化能为141 8kJ/mol。     

低能离子在Mylar膜中的射程研究

研究了低能离子Ｍｙｌａｒ膜中的射程,提出低能离子进入生物样品,在其内部通过溅射产生空洞,使高剂量下的后续离子射程大在增加。并提出了低能离子在生物样品中的最大射程与旧成线性关系,将最大射程与辐射损伤联系起来。