聚丁二烯／液晶复合膜的结构形态研究

在聚丁二烯／液晶复合膜中，液晶的分布方式与液晶含量以及环境温度有关。当液晶含量超过３０％时，５０℃以下液晶呈连续的球状体，５０℃以上液晶相呈连续的流动态。由于聚丁二烯分子与液晶分子的相互分散和交联的影响，使复合膜中的液晶相ＴＫＮ比纯液晶的ＴＫＮ降低了约３０℃。当具有一定压力的气体通过复合膜后，复合膜的结构形态也发生了一定的变化。本研究利用ＤＳＣ、ＳＥＭ、ＴＥＭ及ＯＰＭ对复合膜的结构形态进行了表征，     

顺丁橡胶与液晶共混复合膜的CO2渗透性能

以顺丁橡胶（ＰＢ）和具有双重液晶相的液晶化合物双－４－（４’－乙氧基苯甲酰氧基）苯甲酸－缩乙二醇酯（ＤＥＢＥＢ）制成高分子／液晶复合膜并研究了其ＣＯ２透过性能。液晶含量为１０％（质量）复合膜在室温下具有比ＰＢ膜大５倍以上的ＣＯ２透过系数（Ｐｃｏ２）及好的与Ｎ２、Ｏ２分离系数（αｃｏ２／Ｎ２、αｃｏ２／ｏ２）：Ｐｃｏ２＝４３２ｂａｒｒｅｒ,αｃｏ２／Ｎ２＝２５．４,αｃｏ２／ｏ２＝７．９;且透气系数     

非对称膜及其复合膜结构参数的研究

根据非对称膜及其复合膜与气体渗透之间关系的教学模型，建立了通过测定气体渗透率确定膜结构参数的计算方法，并建立了相应的电算软件，可确定的膜结构参数为涂层厚度，致密层厚度、底膜和复合膜的表面平均孔径及表面孔隙率，并利用此方法确定了两种气体分离复合膜的结构参数。     

液晶复合膜对H2,N2,CO及CO2气体分离性能的研究

本文研究了三种液晶/高分子复合膜对H_2、N_2、CO及CO_2等四种气体的透过情况。实验表明,液晶/高分子复合膜在液晶的熔点以下对H_2及CO_2具有较好的选择性,其原因可能是小分子液晶添加剂使聚合物的致密结构发生了变化。选择性αH_2/N_2、αH_2/CO等在液晶的熔点附近有较大的突跃。渗透系数P_(H_2),P_(CO_2)较之PVC膜均有数量级的提高。液晶分子结构对气体的分离系数有很大影响,液晶分子中是否含有酯基或氰基在液晶的熔点(T_(KN))以上的选择性αH_2/N_2、αH_2/CO、αCO_2╱N_2以及αCO_2/CO等可差别3～4倍。     

刚性二酐改性HQDEA—ODA型聚醚酰亚胺的透气性能

本文合成了一系列刚性二胺改性HQDEA-ODA型聚醚酰亚胺,研究了它们对H_2、O_2、和N_2三种气体的透过性能与分子结构之间的关系。结果表明,第二种二酐单体的结构对共聚醚酰亚胺的透气性能有很大的影响。当第二种二酐单体的含量占二酐单体总量的20%时,其聚醚酰亚胺的透氢系数和H_2/N_2分离系数均比均聚物HQDPA-ODA的高。     

聚丁二烯/液晶复合膜的富氧性能研究

以聚丁二烯为基质，用端基为ＣＨ２＝ＣＨ－的液晶化合物与其共混，交联成膜。用体积法测定膜的透气性能。研究结果发现，此类聚合物／液晶复合膜在５０℃以上有明显的富氧性能，ＰＯ２值最高达１８０Ｂａｒｒｅｒ，氧、氮分离系数在３～５之间，最高达１０左右。同时研究了膜的组成、温度等对膜透气性能的影响。     

取向聚氯乙烯/液晶复合膜表面形态特征研究

模仿生物膜表面的液晶态结构,将有序的、流动的胆甾醇液晶与基质材料聚氯乙烯共混,通过在成膜过程中施加不同强度的电场,制成取向聚氯乙烯/液晶复合膜,作为抗凝血生物材料.通过各种测试手段,考察不同取向条件下复合膜表面液晶畴的取向性能、尺寸、表面形态及其与电场强度、液晶含量的相关关系.结果表明:取向聚氯乙烯/液晶复合膜表面呈现出的形态特征是液晶含量、电场强度和基质材料大分子链诱导作用等综合因素影响的结果;电场强度可以调控液晶畴的体积和取向性;通过适当调节电场强度和液晶含量可获得具有一定相分离程度和有序性的复合膜.     

刚性二酐改性HQDEA-ODA型聚醚酰亚胺的透气性能

本文合成了一系列刚性二胺改性HQDEA-ODA型聚醚酰亚胺,研究了它们对H_2、O_2和N_2三种气体的透过性能与分子结构之间的关系。结果表明,第二种二酐单体的结构对共聚醚酰亚胺的透气性能有很大的影响。当第二种二酐单体的含量占二酐单体总量的20%时,其聚醚酰亚胺的透氢系数和H_2/N_2分离系数均比均聚物HQDPA-ODA的高。     

刚性二酐改性HQDEA-MDA型聚醚酰亚胺的透气性能

合成了一系列刚性二酐改性 HQDEA-MDA 型聚醚酰亚胺,研究了 H_2,O_2 和 N_2的透过性能与分子结构之间的关系。结果表明,在 HQDEA-MDA 分子中引入刚性或半刚性的第二种二酐单体后,在透 H_2系数有所提高的情况下,聚醚酰亚胺的 H_2/N_2选择性明显改善,其中 BPDA 改性的聚醚酰亚胺HQDEA/BPDA-MDA 的透气选择性最好。     

Preparation of porous poly(l-lactic acid)/tobermorite composite membranes via electrospinning and heat treatment

A novel poly(l-lactic acid) (PLLA)/tobermorite composite porous membrane for use as filter materials was synthesized by electrospinning a mixture of tobermorite modified by poly(dialyldimethylammoniumchloride) (PDDA) and PLLA. X-ray diffraction patterns of the sample indicated the existence of tobermorite in the sample. Scanning electron micrographs of the sample showed that the nonwoven membrane consists of a few microscopic fibers despite the existence of tobermorite particles. This was due to repulsive force and surface tension. However, no tobermorite particle was exposed at its fiber surface. Thermal analysis showed PLLA of the sample pyrolyzed with two steps of weight loss (44% at around 170 °C and 34% at around 270 °C). Heat treatment of the sample at 130 and 250 °C led to crystallization of a part of amorphous PLLA in the fiber and elimination of the remaining amorphous PLLA, respectively. After the treatment, the membrane maintained its porous structure and was coated with tobermorite particles at the fiber surface.     

磺化聚醚醚酮/蒙脱土复合型质子交换膜制备与性能

以磺化聚醚醚酮(SPEEK)为基体,以有机改性的蒙脱土(OMMT)为无机相,采用溶液插层法成功制备出了可望应用于直接甲醇燃料电池的SPEEK/OMMT复合型质子交换膜.通过X射线衍射(XRD)表征了复合膜的微观结构,并采用交流阻抗和隔膜扩散方法分别考察了复合膜的质子传导性能和阻醇性能.结果表明,蒙脱土的片层间距超过4.4 nm,SPEEK高分子链已插层到蒙脱土片层之间.与纯SPEEK膜相比,SPEEK/OMMT复合膜的质子传导率有所降低,但在90℃也达到了1.2×10-2S/cm的水平,而且蒙脱土的加入明显地降低了SPEEK膜的甲醇渗透率.     

磺化酚酞型聚醚砜/蒙脱土质子导电复合膜的表征与性能

采用浓硫酸为磺化剂,制备了磺化度为70.26%的磺化酚酞型聚醚砜,并通过添加有机蒙脱土制备了复合质子交换膜.研究了不同含量有机蒙脱土的复合质子交换膜的外观形貌,含水量,热稳定性和质子电导率,发现有机蒙脱土已经很好地分散在聚合物溶液中,复合膜的质子电导率在多种条件下均随着OMMT的添加量的增加而增加,其中SPES-C/OMMT10在80℃下经质子化处理后质子电导率达到8.53×10-4S/cm.     

Preparation and characterization of poly(vinyl alcohol)/poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone)/nano-hydroxyapatite composite membranes for tissue engineering

In this paper, the poly(vinyl alcohol)/poly(epsilon-caprolactone)-PEG-poly(epsilon-caprolactone)/nano-hydroxyapatite (PVA/PCEC/n-HA) composite membranes were prepared by solution casting and evaporation methods. The effect of n-HA content on the properties of the composite membranes was studied. The PVA/PCEC/n-HA composite membranes were analyzed by FTIR spectroscopy, X-ray diffraction, water content measurement, contact angle, mechanical test, scanning electron microscopy. The results showed that the surface roughness of the composite membranes increased with the increase of n-HA contents. The n-HA content had obvious influence on the swelling ratio, tensile strength and elongation rate of the composite membranes. With the increase of n-HA contents, the swelling ratio increased at first, and then decreased; tensile strength and elongation rate decreased gradually. The PVA/PCEC/n-HA composite membranes may be applied in the field of tissue engineering.     

Study on morphology and characterization of poly(mphenylene isophtalamide)/multi-walled carbon nanotubes composite nanofibers by electrospinning

Electrospinning technique is the main method of preparing polymer nanofiber simply, directly and continuously at present. In this work, electrospinning blend solution was prepared by in-situ polymerization using acid-modified multi-walled carbon nanotubes (MWNTs), m-phenylenediamine (MPD) and isophthaloyl chloride (IPC). And then composite nanofibers were prepared by electrospinning. MWNTs played an important role in nanofiber's properties. The effects of MWNTs on the morphology and characterization of the MWNTs/PMIA composite nanofibers were investigated. Scanning electron microscopy (SEM), thermal gravimetric analyzer (TGA), and X-ray diffraction (XRD) were utilized to characterize the MWNTs/PMIA nanofibers morphology and properties. The experimental results indicated that the nanofibers diameter decreased and solution dynamic viscosity increased with increasing MWNTs contents. XRD data demonstrated that PMIA composite nanofibers had the same crystal type as the pure PMIA nanofiber, and crystallinity was improved with increasing MWNTs loading. Transmission electron microscopy (TEM) was used to confirm MWNTs aligned along the axis of composite nanofibers.     

聚醚共聚酰胺-三醋酸甘油酯多层复合气体分离膜的制备及其分离性能

以聚醚共聚酰胺Pebax1074为分离层主体膜材料,以三醋酸甘油酯(GTA)为添加剂,制备具有超薄分离层的Psf/PDMS/Pebax1074和Psf/PDMS/Pebax1074-GTA/PDMS多层复合气体分离膜.考察了Pebax1074和GTA浓度、温度、压力等条件对H2、N2、CH4和CO2等在复合膜中的渗透性能的影响.结果显示,随Pebax1074浓度的增大,Psf/PDMS/Pebax1074膜对气体的渗透通量急剧下降,气体选择性逐渐增大至接近Pebax1074本征值.当GTA质量分数大于50%,Psf/PDMS/Pebax1074-GTA复合膜的气体渗透通量大幅增加,而气体选择性不高.利用硅橡胶对复合膜表面保护后,气体选择性接近Pebax1074材料本征值.Psf/PDMS/Pebax1074-GTA/PDMS多层复合膜对CO2具有较高的渗透通量和较高的选择性.CO2对多层复合膜存在塑化效应,渗透通量随压差增大而增大;随着操作温度的升高,H2、N2、CH4和CO2在复合膜中的渗透通量显著增大,而CO2/(N2、CH4、H2)的分离系数减小.