PVDF-增塑剂共混体系的结晶性及相容性

为提高聚偏氟乙烯(PVDF)的熔融可加工性,将邻苯二甲酸二丁酯(DBP)、环丁砜(SFL)、三乙酸甘油酯(GL)以及碳酸丙烯酯(PC)等4种增塑剂分别用于PVDF的共混改性。采用示差扫描量热仪(DSC)、动态力学分析仪(DMA)以及电子拉力机等分别研究了PVDF-增塑剂共混试样的结晶性、相容性和力学性能。结果表明:当共混试样中增塑剂的质量分数小于10%时,增塑剂与PVDF具有很好的相容性,且共混试样具有很好的断裂强度和断裂伸长率;当增塑剂的质量分数大于10%时,增塑剂与PVDF的相容性变差,发生相分离。     

Polymerizable ionic liquid copolymer P(MMA-co-BVIm-Br) and its effect on the surface wettability of PVDF blend membranes

Polymerizable ionic liquid copolymer P(MMA-co-BVIm-Br) was synthesized by radical polymerization technique, and characterized by Fourier transform infrared spectrometry(FTIR), 1H Nuclear magnetic resonance(1H-NMR) and gel permeation chromatography(GPC). The resulting copolymer was used to prepare poly(vinylidene fluoride)(PVDF) blend membranes via a phase inversion method. The effects of the copolymer on the polymorphism, surface wettability and zeta potential(ζ) of the blend membranes were investigated by ATR-FTIR, contact angle instrument and zeta potential analyzer. Scanning electron microscopy(SEM and SEM-EDS) was also applied to investigate the morphology and the surface element changes of the fabricated membranes. The results indicated that P(MMA-co-BVIm-Br) copolymer existed on the surface of the membrane which made the blend membrane have a positive surface during the experimental p H range. The copolymer was also in favor of the formation of β crystal phase in PVDF membranes. The contact angle experiment indicated that P(MMA-co-BVIm-Br) copolymer could switch the wettability of the blend membranes from hydrophilic to hydrophobic by exchanging Br-anion with PF-6. Compared with pure PVDF membranes, the water flux and water recovery flux of the blend membranes were enhanced obviously. The results from the flux recovery ratio(FR) and total fouling ratio(Rt) all suggested that the blend membranes had good anti-fouling properties.     

两亲性梳状聚醚硅氧烷对相转化法聚偏氟乙烯多孔膜的共混改性作用研究

以聚醚链段为侧链的两亲性梳状聚醚硅氧烷(ACPS)为改性剂,研究了相转化法制备聚偏氟乙烯(PVDF)多孔膜的改性效果与机理.采用SEM、XPS、接触角、水通量等考察了ACPS对膜结构与性能的影响.研究发现,ACPS在相转化成膜过程中不流失,随着制膜液中ACPS含量的增加,相分离速度降低,膜中微孔由指状结构向蜂窝状结构发展,膜强度提高,亲水性显著提高.提出了ACPS在膜表面的富集现象和在膜中的稳定性机理和模型.结果表明,两亲性梳状聚醚硅氧烷在原理上是一类适合于相转化法制备聚合物微孔膜表面亲水化改性的有效物质.     

F127反相微乳液中纳米AgCl粒子的可控合成和AgCl/F127-PMMA有机/无机杂化膜的研究

在大分子F127为表面活性剂的反相微乳液体系中,合成AgCl纳米粒子。然后通过聚合制备AgCl/F127-PMMA有机/无机杂化膜,用于苯/环己烷混合物的渗透汽化分离。利用电导率仪、紫外可见光谱及透射电镜研究微乳液的增溶水量(ω)对微乳液结构、胶束中AgCl粒子的生成和形貌的影响。结果表明:合成的AgCl粒子粒径小于10 nm;增加微乳液的ω,生成的AgCl粒子变大。聚合后制备的AgCl/F127-PMMA有机/无机杂化膜中,AgCl粒子能保持较好的分散性。50wt%苯/环己烷混合物的渗透汽化结果表明,在合适的ω下,所制备的AgCl/F127-PMMA有机/无机杂化膜能克服常规高分子膜的trade-off现象,表现出较好的分离性能。