薄膜用聚丙烯树脂熔融态PVT行为的研究

利用PVT 10 0分析仪对 5种不同牌号的双向拉伸用聚丙烯 (BOPP)树脂的压力 体积 温度 (PVT)特性进行了测定 ,并利用Tait方程法得出BOPP熔体的热膨胀系数 (α)随温度和等温压缩系数 (β)随压力的变化关系 .研究结果表明 ,在相同条件下 ,牌号为S2 8C的BOPP熔体的热膨胀系数、等温压缩系数和结晶熔融温度分别低于其它牌号 ,因此 ,我们推断S2 8C在冷片形成过程中的体积形变较小 ,可避免由于收缩产生的模片表面缺陷 ,进而减少在后续双向拉伸过程中的破膜现象     

梯度薄膜增敏的光波导表面散射传感方法用于生物气溶胶探测

生物气溶胶监测对于疾病防控、防化反恐、环境保护与资源调查等至关重要。本研究提出了一种基于高折射率梯度薄膜增敏的平板玻璃光波导表面散射传感方法,通过探测光波导散射光强度随时间的变化,分析生物气溶胶在光波导表面的颗粒沉降过程,进而获取生物气溶胶的浓度等信息。本研究通过理论推导得出光波导散射光强度与沉降粒子数之间的函数关系式,选用牛血清蛋白(BSA)水溶液作为生物气溶胶原液,采用五氧化二钽(Ta₂O₅)梯度薄膜增敏的离子交换平板玻璃单模光波导测试了BSA分子团聚体沉降引起的表面散射光变化,通过比对测试分析了Ta₂O₅梯度薄膜的增敏效果。实验结果表明,散射光强度随BSA分子团聚体沉降量的增加而增大,与BSA原液浓度呈良好线性关系,当单模玻璃光波导表面覆盖Ta₂O₅梯度薄膜后,其在横电基模(TE0)下对BSA分子团聚体沉降的探测灵敏度提高了50倍,并且采用TE0模测得的探测灵敏度比横磁基模(TM0)高4倍。本研究制备的Ta₂O₅     

质子交换膜燃料电池梯度化膜电极

为实现质子交换膜燃料电池的高性能(高功率密度或大电流密度)、低成本(低铂载量)、长寿命发电,人们尝试在燃料电池的核心部件膜电极结构中引入梯度化设计的概念。梯度化膜电极包括膜电极中各组件的梯度化:气体扩散层的PTFE含量与孔隙率的梯度化,催化层的催化剂与Nafion用量的梯度化以及微孔层的疏水性与孔隙率的梯度化。梯度化膜电极中催化剂分布、孔隙率分布、亲/疏水性分布合理,具有良好的三相反应界面以及质子、电子、反应气体、水等多相物质高效传输通道,从而能满足在低铂载量、低加湿以及高电流密度条件下高性能稳定工作。本文整理了近几年来有关燃料电池梯度化膜电极研究的相关文献,梳理了梯度化膜电极研究发展脉络,归纳总结了各种梯度化膜电极的制备方法、性能以及构效关系,并展望了梯度化膜电极下一步研究方向,对高性能、低成本、长寿命的燃料电池开发具有指导意义。     

高温凝胶渗透色谱法测定聚丙烯的相对分子质量及分布

双向拉伸聚丙烯(BOPP)是一种用于生产薄膜的高分子材料,该材料具有透明、有一定阻隔性、挺括、强度高、无毒等优越性。由于相对分子质量分布是影响BOPP加工性能、力学性质的主要因素,相对分子质量分布宽时,会导致在薄膜生产中趋向边缘比中间稍厚,而相对分子质量分布窄时,中间比边缘厚。前者所得薄膜更有利于横向拉伸,而后者易拉伸破膜。同时,相对分子质量分布加宽会使BOPP的熔体强度增大,有利于减轻挤出厚片的熔垂,因此适当的相对分子质量分布有利于加工。此类薄膜对相对分子质量及分布的要求比较严格,     

浸润性梯度表面研究与应用

浸润性梯度表面是指表面浸润性随着表面位置的变化而连续变化的一种特殊梯度表面.在过去的20年间,由于浸润性梯度表面在智能涂料、微流体器件和液体自输送等方面具有广阔的应用前景,因此人们研发并制备了各种类型的浸润性梯度表面,总体而言,可分为三类:(1)化学组成类浸润性梯度表面;(2)表面形貌类浸润性梯度表面;(3)化学组成-表面形貌复合型浸润性梯度表面.重点介绍了这三大类浸润性梯度表面的分类与区别,以及近些年来这些新型浸润性梯度表面的主要制备方法,如扩散法、浸泡法、刻蚀与打印、机械拉伸法、半月板沉积法和温度梯度法等,并归纳总结了这些方法的各自优缺点.在目前的材料科学领域,虽然关于浸润性梯度的研究还属婴儿期.可是利用梯度表面研究生物蛋白或细胞吸附,液体自输送等,已经发展成为一门成熟的学科.最后综述了近期关于浸润性梯度表面在研究生物蛋白或细胞吸附,液体自输送等方面的应用进展,并展望了该课题的未来发展.     

聚苯并咪唑/磺化苯膦酸锆质子交换杂化膜的制备与表征

为了提高质子交换膜在高温和低湿度条件下的热稳定性、机械性能和质子传导性能,将新型质子导体磺化苯膦酸锆(Zirconium Sulfophenylphosphonate,Zr SPP)引入聚苯并咪唑(Polybenzimidazole,PBI)有机基体中制备PBI/Zr SPP质子交换杂化膜。分别采用扫描电镜(SEM)、拉伸测试、热稳定性分析(TGA)和交流阻抗法对质子交换杂化膜的微观结构及性能进行表征。考察了Zr SPP在膜内的分散性及其加入对质子交换杂化膜的热稳定性能,机械性能及质子传导性能的影响。实验结果表明,Zr SPP均匀的分布在质子交换杂化膜中;Zr SPP的加入增强了质子交换杂化膜的热稳定性能;在外界不加湿的条件下,PBI/5%Zr SPP质子交换杂化膜的质子电导率在160℃可达到38m S/cm。PBI/5%Zr SPP质子交换杂化膜的拉伸强度为43.0MPa,具有比Nafion117(拉伸强度26.6MPa)更好的机械性能。     

基于表面起皱法的梯度图案的可控制备

报道了基于非刻蚀法的表面起皱机制来实现高分子薄膜表面的周期性梯度图案的简单可控制备.即对于处于机械拉伸状态的聚二甲基硅氧烷(PDMS)弹性基底,在其底部垫入"积木",而后对其进行紫外-臭氧(UVO)和氧等离子体(OP)的联合表面处理."积木"的加入引起了表面处理后表面硅氧层(SiOx)梯度厚度的形成,进而当释放拉伸应变后,诱导产生了梯度皱纹图案.结果表明:当UVO与OP联用处理时,不仅实现了较小拉伸应变下梯度皱纹形貌的制备,而且扩大了UVO单独使用时梯度皱纹周期的变化范围.通过OP与UVO的处理顺序和处理时间等因素的简单调节,进一步实现了不同梯度皱纹微结构的精细构筑.     

预氧化聚烯烃膜的表面光接枝聚合

将经表面热氧化的聚丙烯和聚乙烯膜在不加敏化剂的情况下,通过紫外光照射与光稳定剂甲基丙烯酸(2,2,6,6-四甲基哌啶)酯进行接枝聚合,以改善膜的光稳定性。研究了各种因素,包括热氧化时间,光照射时间、单体浓度及溶剂等对表面预氧化膜的光接枝含量的影响。实验结果表明,常用的有机溶剂除酮类外均不能使膜接枝;接枝以后膜的光稳定性有很大的提高。     

静电纺丝制备具有浸润性梯度的聚酰亚胺纳米纤维膜

采用高压静电纺丝技术, 在非对称异型电极上制备得到放射状聚酰亚胺(PI)纳米纤维膜. 采用环境扫描电子显微镜(ESEM)观察了PI膜的微观形貌以及纳米纤维的排列状态; 采用接触角测量仪研究了水滴浸润性的变化; 采用高敏感性力学微电力学天平测量了水滴的黏附力, 分析了微观形貌变化与水滴浸润性质和黏附性质的关系. 结果表明, 该PI纳米纤维膜沿着非对称异型电极三角电极至弧型电极方向纤维排列由密到疏, 呈放射状, 具有独特的微结构梯度; 整个纤维膜上的PI纳米纤维直径均一且具有光滑均匀表面, 纤维与纤维之间的距离约为几微米到几十微米. 由于PI纳米纤维膜所具有的独特的微结构梯度, 致使沿着微结构梯度方向水滴的接触角(从超疏水到疏水)和黏附力(从低黏附到高黏附)均表现出梯度变化的特征.     

具有不对称孔道结构的小介孔二氧化硅粒子的合成及其高分子杂化膜的构建

利用手性阴离子酸表面活性剂, 采用软模板法制备了具有不对称孔道结构的小介孔二氧化硅(SiO₂)粒子. 将小介孔SiO₂粒子引入聚偏四氟乙烯(PVDF)和聚酰亚胺(PI)中构建了两种有机/无机杂化膜. 利用傅里叶变换红外光谱(FTIR)、 透射电子显微镜(TEM)、 扫描电子显微镜(SEM)和比表面积分析等表征了小介孔SiO₂粒子和有机/无机杂化膜的微结构, 并通过超滤实验和气体渗透实验分别考察两种杂化膜的性能. 研究结果表明, 表面含有大量亲水基团的小介孔SiO₂粒子具有规则有序排列的孔道结构, 该孔道结构呈现螺旋扭曲和不对称性. 构建的两种有机/无机杂化膜的极性显著提升, 进而有效增强了PVDF杂化膜的膜通量和抗污染性能及PI杂化膜对CO₂气体的分离性能, 克服了高分子膜的博弈效应(Trade-off效应). 另外, SiO₂的小介孔孔道还可以在PI杂化膜中引入优先通过CO₂分子的限域传质通道, 加速了CO₂气体在杂化膜中扩散. 但过多小介孔SiO₂粒子的加入导致其在高分子基质中团聚, 削弱杂化膜的极性和亲水性, 从而降低了两种杂化膜的分离性能.     

An inkjet printing soft photomask and its application on organic polymer substrates

This article presents a simple, fast and low-cost method to fabricate a flexible UV light photomask. The designed micropatterns were directly printed onto transparent hybrid composite film of biaxially oriented polypropylene coated with silica oxide (BOPP-SiO _x ) by an inkjet printer. Compared to the conventional chrome-mask, it is of advantages such as suitable for non-planar substrates, scalable for large area production, and extreme low cost. Combined with the confined photo-catalytic oxidation (CPO) reaction, the printed flexible BOPP-SiO _x photomask was successfully used to pattern the shape of wettability of organic polymer surfaces, and then polyaniline patterns were deposited on the modified substrates with strong adhesion. With the above photomasks, the polyacrylic acid graft chains were duplicated on the poly (ethylene terephthalate) (PET) and BOPP substrates by photografting polymerization. We grafted polyacrylic acid (PAA) on a non-planar plastic substrate with this soft and thin plastic photomask. Scanning electron microscopy (SEM) and optical microscopy were used to characterize the surface morphology and thickness of ink layers of the printed photomask. Optical microscopy was used to characterize the deposition polyaniline micropatterns. It was found that the desired patterns were precisely printed on the modified polymer films and were applied in modifying organic polymer substrates. The printed photomask could be exploited in the fields such as prototype microfluidics, micro-sensors, optical structures and any other kind of microstructures which does not require high durability and dimensional stability.     

表面接枝含氟苯乙烯共聚物的聚酯薄膜制备与表征

利用表面引发原子转移自由基聚合(SI-ATRP)在聚对苯二甲酸乙二醇酯(PET)薄膜表面接枝苯乙烯和4-氟苯乙烯的共聚物.研究不同反应时间和不同配比下接枝共聚物对聚酯薄膜表面组成、结构和性能的影响.通过傅利叶变换红外光谱仪(ATR/FTIR),X-射线光电子能谱仪(XPS),凝胶渗透色谱(GPC)和扫描电子显微镜(SEM)对接枝改性前后PET薄膜的表面组成,结构和形貌进行分析;利用接触角测试和表面能计算对比研究接枝改性前后PET薄膜的表面性能.结果表明反应时间和单体百分含量对接枝百分率及接触角有一定的影响,随着反应时间的增长,聚酯薄膜表面接枝百分率增大,接触角增加,表面自由能下降.     

Graft copolymerization kinetics of acrylic acid onto the poly(ethylene terephthalate) surface by atmospheric pressure plasma inducement

After one atmospheric pressure plasma treatment of poly(ethylene terephthalate) (PET) film, acrylic acid (AAc) in aqueous solution was successfully graft‐copolymerized onto PET films. The effects of reaction time, AAc monomer concentration and reaction temperature on grafting behavior of AAc were systematically studied. Possible reaction kinetics of plasma‐induced graft copolymerization, starting from initial hydroperoxide decomposition, were proposed. Through the Arrhenius analysis about graft copolymerization kinetics of AAc monomers on PET surface, it was revealed that the activation energies of decomposition, propagation and termination were 98.4, 63.5, and 17.5 kJ/mol, respectively. The temperature around 80 °C was favorable not only for the formation of oxide radicals through the thermal decomposition of hydroperoxide on PET surface but also for the extension of graft copolymer chain through direct polymer grafting. Poly(acrylic acid) (PAAc) grains grafted onto PET surfaces possessed relatively uniform size and both PAAc grain size and surface roughness increased with increasing the grafting degree of AAc. The increase of grain size with increasing grafting degree results from the possibility of forming long chain graft copolymers and their shielding of reactive sites. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1594–1601, 2008     

Multiple levels hydrophobic modification of polymeric substrates by UV‐grafting polymerization with TFEMA as monomer

The hydrophobic solid surface modification with fluorine‐containing monomers has received tremendous attention because of its unique structure and excellent property. However, these hydrophobic films normally suffer from two major problems: one is weak interface interaction between fluoropolymers and substrates, and the other is the high cost of fluorine‐containing monomers. Herein, with the aim of feasible industrial application, a facile in situ UV photo‐grafting method is reported, which could ensure the formation of chemical bonds between fluoropolymer‐grafted layer and substrate with a low cost commercial 2,2,2‐trifluoroethyl methacrylate (TFEMA) as monomer. With low‐density polyethylene (LDPE) film as a model substrate, four kinds of poly‐TFEMA‐grafted layer are fabricated on LDPE films with different surface morphologies: polymer brush, polymer network, crosslinked nanoparticles, and a micro‐ and nanoscale hierarchical structure. The experimental results showed that the water contact angles (CAs) of the LDPE films grafted with polymer brush, polymer network, and crosslinked nanoparticles were (103 ± 2)°, (95 ± 2)°, and (122 ± 2)°, respectively, which were much higher than that of LDPE film. The introduction of micro‐ and nanoscale hierarchical structures can dramatically improve the surface roughness, which will further enhance the film hydrophobicity, and the water CA can reach as high as (140 ± 1)°. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1059–1067     

Adaptive nanomechanical response of stratified polymer brush structures

We have fabricated a stratified polymer surface film with tunable thickness (within 17-34 nm) through facile, room-temperature, UV-initiated polymerization with a temperature-sensitive pNIPAAM layer confined beneath a hydrophobic layer. AFM morphology and ellipsometric measurements were measured at each grafting step, along with XPS measurements of the overall layer to verify layer growth. The strong characteristic LCST behavior of pNIPAAM was observed in water, with a 100% change in thickness above and below this transition. The AFM nanomechanical results demonstrate vertical gradients of the elastic response tunable to a desired state by the external temperature. These temperature-sensitive, adaptive polymer structures with the pNIPAAM layer "hidden" beneath the rubbery, hydrophobic PBA topmost layer represent an interesting example of nanoengineering surfaces with properties such as adhesion, elastic modulus, and multi-level structural reorganization responsive to fluidic and temperature variations that can be important for biological purposes such as implant coatings, cell-surface mimicry, and drug delivery vehicles.     

Surface interpenetrating networks of polyacrylamide in poly(ethylene terephthalate) as a means of surface modification

Surface interpenetrating network (IPN) polymers are emerging hybrid materials in which the surface of existing polymers can be modified to preserve their chemical structure and bulk properties. A detailed structural characterization of poly(ethylene terephthalate) (PET) thin films on nanoscopically flat silicon wafers has been carried out by Scanning Probe Microscopy (SPM) and X-ray photoelectron spectroscopy (XPS). Examination of the surface of spin-coated annealed PET film by the SPM in tapping mode revealed a two-phase structure. One phase appeared as a dense crystalline fraction of the polymer while the other was identified as amorphous. These findings were supported by Differential Scanning Calorimetry (DSC), which recognized the crystallinity of annealed PET film at 30%. Modification of the PET surface with interpenetrating polyacrylamide (PAM) increased the roughness of the surface with uniform properties. The depth profiling with XPS revealed that PAM interpenetration extended down to 7.2 nm, confirming a three-dimensional character of the polymer modification, with a relative mass concentration of PAM at about 30.7% in the IPN interface.     

Characterization of poly(sodium styrene sulfonate) thin films grafted from functionalized titanium surfaces

Biointegration of titanium implants in the body is controlled by their surface properties. Improving surface properties by coating with a bioactive polymer is a promising approach to improve the biological performance of titanium implants. To optimize the grafting processes, it is important to fully understand the composition and structure of the modified surfaces. The main focus of this study is to provide a detailed, multitechnique characterization of a bioactive poly(sodium styrene sulfonate) (pNaSS) thin film grafted from titanium surfaces via a two-step procedure. Thin titanium films (～50 nm thick with an average surface roughness of 0.9 ± 0.2 nm) prepared by evaporation onto silicon wafers were used as smooth model substrates. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed that the titanium film was covered with a TiO(2) layer that was at least 10 nm thick and contained hydroxyl groups present at the outermost surface. These hydroxyl groups were first modified with a 3-methacryloxypropyltrimethoxysilane (MPS) cross-linker. XPS and ToF-SIMS showed that a monolayer of the MPS molecules was successfully attached onto the titanium surfaces. The pNaSS film was grafted from the MPS-modified titanium through atom transfer radical polymerization. Again, XPS and ToF-SIMS were used to verify that the pNaSS molecules were successfully grafted onto the modified surfaces. Atomic force microscopy analysis showed that the film was smooth and uniformly covered the surface. Fourier transform infrared spectroscopy indicated that an ordered array of grafted NaSS molecules were present on the titanium surfaces. Sum frequency generation vibration spectroscopy and near edge X-ray absorption fine structure spectroscopy illustrated that the NaSS molecules were grafted onto the titanium surface with a substantial degree of orientational order in the styrene rings.     

Fabrication and characterization of superhydrophobic silica nanotrees

Superhydrophobic silica nanotrees were obtained by sol–gel method with hybrid silica sol and jelly-like resorcinol formaldehyde resin. Rough surfaces were obtained by removing the organic polymer at high temperature. After the films with rough surface were modified by trimethylchlorosilane (TMCS), the wettability of the film changed from superhydrophilic to superhydrophobic. The surface roughness of the silica nanotrees film is about 20 nm, and it is transparent and superhydrophobic with a water contact angle higher than 150°.     

Preparation of Cu-Coated Stainless Steel Surfaces for Surperhydrophobic Investigation

Cu-coated stainless steel surfaces containing micro- and nanoscale binary structures having different surface roughness were successfully fabricated by means of a facile one-step electroless plating technology, and the resulting surfaces were modified by the low free energy material HFTHTMS (HFTHTMS = (heptadecafluoro-1,1,2,2-tetrahydrodecyl) trimethoxysilane). The experimental results of wettability exhibit that such unmodified surfaces have a strong adhesive force to water droplets, and their contact angles increase with increasing surface roughness, whereas the modified surfaces by HFTHTMS show the superhydrophobic characteristic with contact angles higher than 150° and sliding angles lower than 5°.     

电火花引发丙烯酰胺接枝BOPP薄膜的研究

采用FT-IR,ESCA,试样与水接触角和接枝率的测定探索了电火花用于引发丙烯酰胺(AAM)在BOPP薄膜表面接枝聚合反应的方法,研究了接枝BOPP薄膜的表面结构和亲水性能。结果表明,电火花能有效地引发AAM在BOPP薄膜表面的接枝聚合反应,随着电火花处理时间和接枝反应时间的延长,AAM在BOPP薄膜表面的接枝率增大。电火花处理10min,BOPP薄膜在70℃,20%(质量分数)的AAM水溶液中反应1h,接枝率高达2.06%。接枝后BOPP薄膜与水的接触角显著下降,亲水性能得到明显改善。