Surface properties of polymers treated with tetrafluoromethane plasma

Polymer films of poly(ethylene terephthalate), polypropylene, and cellophane were surface treated with tetrafluoromethane plasma under different time, power, and pressure conditions. Contact angles for water and methylene iodide and surface energy were analyzed with a dynamic contact angle analyzer. The stability of the treated surfaces was investigated by washing them with water or acetone, followed by contact angle measurements. The plasma treatments decreased the surface energies to 2–20 mJ/m² and consequently enhanced the hydrophobicity and oleophobicity of the materials. The treated surfaces were only moderately affected after washing with water and acetone, indicating stable surface treatments. The chemical composition of the material surfaces was analyzed with X-ray photoelectron spectroscopy (XPS) and revealed the incorporation of about 35–60 atomic % fluorine atoms in the surfaces after the treatments. The relative chemical composition of the C ls spectra's showed the incorporation of —CHF— groups and highly nonpolar —CF₂— and —CF₃ groups in the surfaces and also —CH₂—CF₂— groups in the surface of polypropylene. The hydrophobicity and oleophobicity improved with increased content of nonpolar —CF₂—, —CF₃, and —CH₂—CF₂— groups in the surfaces. For polyester and polypropylene, all major changes in chemical composition, advancing contact angle, and surface energy are attained after plasma treatment for one minute, while longer treatment time is required for cellophane. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1591–1601, 1997     

立体旋液式并流塔板的海水脱硫特性

引言海水烟气脱硫技术是利用天然海水的弱碱性吸收烟气中的SO2,达到净化烟气的目的[1-4]。该技术在最近四十年内已在世界范围内众多大型电厂实现工业化应用[5-6],目前,多数海水烟气脱硫系统采用ABB(即ALSTOM)公司的Flakt-Hydro工艺[7-8],以脱硫塔作为主要的吸收设备,如:喷淋     

Cr5Mo合金钢的焊接工艺

Cr5Mo钢是以铬钼为基本合金元素的合金钢,其金相组织为珠光体,具有优良的耐高温硫腐蚀性、耐氧化性及较高的高温强度,但Cr5Mo钢焊接性差。本文分析了Cr5Mo钢的冷裂纹倾向和再热裂纹敏感性及产生缺陷的原因,并提出了相关工艺及施工中的注意事项。     

芳纶纤维增强树脂基复合材料的界面粘结性能研究

为了改善芳纶纤维增强树脂基复合材料的界面粘结性能,从树脂基体入手,依据相似相容原理和芳纶的结构特点,合成出新型热固性树脂(AFR–T)用作芳纶复合材料的基体,以未经表面处理的芳纶作增强材料,采用热压成型法制备了AFR–T/芳纶纤维复合材料,并通过测定溶度参数、接触角、线膨胀系数、层间剪切强度(ILSS)和横向拉伸强度等方法研究了复合材料的界面粘结性能。结果表明,AFR–T树脂浇注体与芳纶的溶度参数相近,AFR–T树脂溶液在芳纶纸表面的接触角为36.9°,小于环氧树脂(EP)溶液与芳纶纸的接触角(53.2°),说明AFR–T树脂对芳纶的浸润性优于EP;AFR–T/芳纶纤维复合材料的ILSS和横向拉伸强度为73.0 MPa和25.3 MPa,分别比EP/芳纶纤维复合材料提高了25.9%和32.5%,这表明AFR–T树脂与芳纶纤维之间的浸润性和界面粘结性能较好。     

聚四氟乙烯超疏水薄膜的制备和表征

通过乳液聚合反应制得聚苯乙烯(PS)乳液,将PS按照不同的体积比和聚四氟乙烯(PTFE)乳液混合得到杂化乳液。使用浸渍提拉法制备薄膜,在80℃烘干,330℃和420℃进行热处理,当PS与PTFE两种乳液体积比为0.6时得到超疏水薄膜,薄膜与水的接触角最高可达152.4°。使用场发射电子显微镜(FESEM)、Jupiter同步热分析仪和傅里叶红外光谱仪(FTIR)对薄膜的表面形貌和化学组成进行了表征。     

空气助力改善气化炉激冷室喷嘴特性的实验研究

设计了4种不同结构的用于气化炉激冷室内喷雾激冷的压力雾化喷嘴,采用马尔文激光粒度分析仪和数码单反照相机分别测量了不同压差、不同水流量等工况参数下的液滴粒径(SMD)D32分布和雾化角变化规律,并对4种喷嘴进行了优化选型。研究结果表明:雾滴粒径随压力的增加而减小,随水流量的减小而减小,空气助力可以明显改善液滴的雾化质量;雾化角随压差的增大先增大后趋于平缓;当压差增大到0.4 MPa时,雾滴粒径、雾化角等参数的变化渐趋平缓。通过比较气化炉激冷室中4种压力式雾化喷嘴的测量结果,1-2号内混式空气雾化喷嘴在4组喷嘴中具有最好的雾化效果,当气压为0.8 MPa,水流量为20 L/h时,SMD极小值为16,因此优选出喷嘴1-2作为气化炉激冷室冷模实验的定型喷嘴。     

DDS-SiO2提高搪瓷表面疏水性的研究

通过溶胶-凝胶法,以正硅酸乙酯(TEOS)为前驱体,利用二甲基二氯硅烷(DDS)在搪瓷粗糙表面覆盖一层-CH3基团,形成疏水薄膜,制备出具有疏水性功能的搪瓷表面。采用傅立叶红外光谱仪和静滴接触角测量仪对薄膜进行了表面结构和性能分析。结果表明:搪瓷的表面存在-CH3和Si-O-Si基团,接触角达110°以上,低表面能是搪瓷表面获得疏水性的重要条件。     

耐硫变换低变工艺管道焊缝裂纹修复小结

通过对气体净化耐硫变换低变工艺管道出现的焊缝泄漏现象进行原因分析,制定了修复方案进行修复,实践证明修复措施是可行的。     

Electrospun Polyvinyl Borate/Poly(Methyl Methacrylate) (PVB/PMMA) Blend Nanofibers

The aim of this study was to prepare polyvinyl borate (PVB)/poly(methyl methacrylate) (PMMA) blend nanofibers by electrospinning process. Polyvinyl borate was synthesized by the condensation reaction of polyvinyl alcohol and boric acid. FTIR analyses showed that boron atoms were found to be integrated into the polymer network. Blending PMMA with PVB decreased the fiber diameter and enhanced the surface roughness of PVB/PMMA blend nanofiber mats. The water wetting property of the nanofiber mats was influenced by the surface roughness. The blend composition with the highest polyvinyl borate content was found to be suitable for thermally stable nanofiber formation.     

石灰石粉复合粉煤灰水泥的制备及对混凝土性能影响

采用石灰石粉和Ⅲ级粉煤灰作为混合材制备复合水泥,通过粉煤灰和石灰石粉的复合比例和掺量来优化水泥性能,并用所制备的水泥配制混凝土,研究其对混凝土强度和抗裂性能的影响。结果表明:随着石灰石粉掺量的增加,复合水泥的标准稠度用水量明显下降,饱和掺量点提前,对外加剂的适应性表现良好;粉煤灰和石灰石粉的复合比例在7:3～6:4,混合材掺量为20%～40%时,可以配制出42.5和32.5的复合硅酸盐水泥;自制复合水泥所配制混凝土的工作性和强度与重庆涪陵腾辉生产的水泥差别不大,裂缝数目和面积减少,抗裂性明显改善。