Preparation and Characterization of Poly(Acrylonitrile-co-Maleic Anhydride) Copolymer Modified Polyethersulfone Membranes

In this study, modified polyethersulfone (PES) membrane with pH sensitivity and heavy metal ion adsorption was prepared by blending a copolymer of poly(acrylonitrile-co-maleic anhydride) (P(AN-MA)). The copolymer was synthesized by free radical reaction using deionized water as the solvent, and was characterized by Fourier transform infrared spectroscopy (FTIR) analysis, elemental analysis, and gel permeation chromatography technique (GPC) measurement. Scanning electron microscopy (SEM) was used to investigate the morphology of the membrane. The modified PES membranes showed excellent pH sensitivity and pH reversibility. Furthermore, the modified PES membrane had the ability to absorb Ag⁺, Cu²⁺, Fe²⁺, and Fe³⁺. In addition, three simplified kinetic models (pseudo-first-order, pseudo-second-order, and intraparticle diffusion model) and adsorption isotherms (Langmuir and Freundlich) were used for the analysis of Cu²⁺ adsorption.     

Poly(Acrylic Acid-co-Acrylonitrile) Copolymer Modified Polyethersulfone Hollow Fiber Membrane with pH-Sensitivity

In this study, functional polyethersulfone (PES) hollow fiber membranes with pH sensitivity were prepared by blending with poly(acrylic acid-co-acrylonitrile) (P(AA-AN)) copolymer. The copolymer was characterized by FTIR analysis, elemental analysis, and GPC measurement. Scanning electron microscopy (SEM) was used to investigate the morphology of the blended hollow fiber membranes. The modified hollow fiber membranes showed excellent pH sensitivity and pH reversibility and we confirmed that both the pore size change and the electroviscous effect had great effect on the pH sensitivity of the copolymer blended PES hollow fiber membranes.     

Hollow Fiber Ultrafiltration Membranes from Poly(Vinyl Chloride): Preparation,Morphologies, and Properties

Hollow fiber poly(vinyl chloride) membranes were prepared by using the dry/wet spinning method. Cross-section, internal, and external surfaces of the hollow fibers structure were studied by SEM. The pore size and pore size distribution of the hollow fibers were measured by a PMI capillary flow porometer. UF experiments of pure water and aqueous solution of PVP K-90 were carried out. The effect of the PVC concentration on the hollow fibers mechanical properties was also investigated. It was found that the PVC fibers cross-sectional structure was affected by the polymer concentration in the dope solution. In particular, reduction of macrovoids size was observed when increasing PVC concentration from 15 to 19 wt%. The pore size distribution of the PVC hollow fibers was controlled by adjusting the PVC concentration. Indeed, an increase of PVC concentration up to 19 wt% leads to fibers with sharp pore size distribution (the 99% of pores is about 0.15 µm).The pure water permeation flux decreased from 162 to 128 (l/m² · h · bar), while the solute separation performance increased from 82 to 97.5%, when increasing the PVC concentration. The elongation at break, the tensile strength, and the Young's modulus of the PVC hollow fibers were improved with PVC concentration in dope solution.     

Physical Properties of Plasticized Poly(vinyl chloride) Blended with Poly(methyl methacrylate) Nanoparticles Synthesized by Differential Microemulsion Polymerization

In this work, poly(methyl methacrylate) (PMMA) nanoparticles synthesized by differential micro emulsion polymerization were used to improve the physical properties of plasticized poly(vinyl chloride) (PVC). PVC, plasticizer (40 phr), heat stabilizer (2 phr), and lubricant (0.2 phr) were melt-mixed with varied amount of the PMMA nanoparticles (3, 5, 7, and 9 phr) on a two-roll mill, followed by compression molding. The results showed that the tensile strength, Young's modulus, tear strength, and thermal stability were improved, but the elongation at break deteriorated with increased PMMA content. Moreover, the flammability of the plasticized PVC was not improved by the PMMA nanoparticles.     

磺化聚醚醚酮纳米纤维膜的制备及其吸附性能

通过静电纺丝法制备了不同磺化度的磺化聚醚醚酮(SPEEK)纳米纤维膜,运用扫描电镜、热重分析仪分别对纤维的形貌和热性能进行了分析,并利用紫外-可见分光光度计研究了纤维膜对亚甲基蓝染料的吸附行为。结果表明:随着磺化度的增加,纺丝束流的稳定性得到改善,纤维直径减小;纤维膜对亚甲基蓝具有良好的吸附能力,在p H值=7时其对亚甲基蓝的去除率最大,平衡吸附时间约为90min;热力学分析表明,使用Freundlich模型描述SPEEK纳米纤维膜对亚甲基蓝的吸附行为更加合理;动力学分析表明,SPEEK纳米纤维膜对亚甲基蓝的吸附遵循准二级动力学模型。     

聚甘油酯化改性PMVE/MAH的合成及吸水性能研究

以甲基乙烯基醚/马来酸酐共聚物(PMVE/MAH)与十聚甘油为原料,采用溶剂接枝法,制得聚甘油酯化改性PMVE/MAH。采用红外光谱和热分析仪对酯化产物进行了结构表征。研究了反应酯化率对产物性能的影响,考察了产物的热稳定性、保水性能、耐电解质性和重复吸水性能。结果表明,酯化率12.5%的共聚物吸水性最强,pH=7时吸水倍率为353 g/g,最适宜酸碱性条件为pH=8,此时酯化改性共聚物吸水倍率可达719 g/g,耐盐性良好,50℃环境温度下16 h仍有67.2%的保水率。     

Preparation of compatible blends of poly(methyl methacrylate) used in dentistry with a reactive terpolymer containing maleic anhydride and their thermomechanical characterization

This study focuses on the preparation of compatible blends with the poly(methyl methacrylate) (PMMA) using a reactive terpolymer maleic anhydride–styrene–vinyl acetate (MA–St–VA). In the first series of experiments, binary blends of the PMMA and the MA–St–VA terpolymer have been prepared in tetrahydrofurane. The PMMA and the MA–St–VA terpolymer formed the compatible blends. The effects on thermomechanical properties of MA–St–VA terpolymer ratio in the blends were studied. The glass transition temperatures (T_g), thermal expansion coefficient (α), and other thermomechanical parameters for the blends have been established by TMA method and the compatibility of two polymers has been evaluated by these TMA parameters. The addition of MA–St–VA terpolymer to PMMA made a plasticizing effect on PMMA. This effect regularly changed with the increasing of the terpolymer in the blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 363–367, 2006     

聚甲基丙烯酸甲酯／纳米SiO2复合粒子的制备与表征

采用甲基丙烯酸-3-甲氧基硅丙酯（MPs）对分散于甲基丙烯酸甲酯（MMA）中的纳米SiO2粒子进行偶联改性，得到了表面改性的纳米SiO2单体分散液，用原位悬浮聚合方法制备了不同SiO2含量的PMMA／纳米SiO2复合粒子。通过红外光谱、透射电镜、差示扫描量热分析和热重分析等方法对制备的纳米复合粒子进行了表征，结果表明，纳米SiO2粒子在PMMA中分散良好；MMA可通过与MPS的共聚而有效地接枝到SiO2粒子表面，当SiO2含量为6．6％（质量分数，下同）、MPS用量为0．06g／gSiO2时，其接枝率可达73．8％；同时，纳米SiO2的引入可提高PMMA的耐热性能，当Si02含量为14.7％时，其玻璃化转变温度和最大热分解速率时的温度分别提高了11．8℃和18．8℃。     

Phase Behaviour of Poly(ethylene oxide)/Poly(styrene-co-maleic anhydride) Blends

Thermal behaviour and morphology of blends of poly(ethylene oxide) (PEO) and poly(styrene-co-maleic anhydride) (SMA) prepared by the coprecipitation technique were studied by means of differential scanning calorimetry, optical microscopy and thermogravimetry. SMA containing 25wt% maleic anhydride (MA) was found to be miscible with PEO when the SMA content was greater than 80%. The melting temperature and crystallinity depended on the composition of the blend. SMA appears to segregate interlamellarly during the isothermal crystallization of PEO. The thermal stability of blends was enhanced and was higher than that of pure PEO and SMA. © of SCI.     

羟基保护法制备聚(D-乳酸-葡萄糖)共聚物及其性能研究

以α-D-葡萄糖为原料,采用羟基保护法制备1,2:5,6-双-O-异丙叉基-α-D-呋喃葡萄糖(ODG),并与聚D-乳酸(PDLA)熔融共聚合成聚(D-乳酸-1,2:5,6-双-O-异丙叉基-α-D-呋喃葡萄糖)共聚物(PDLAODG),然后水解脱羟基制备聚(D-乳酸-葡萄糖)共聚物(PDLAG).采用核磁共振氢谱、傅...     

聚醚砜质量分数对聚偏氟乙烯/聚醚砜共混膜性能和结构的影响

用与聚醚砜共混的方法来改善聚偏氟乙烯膜的抗收缩性能,以二甲基乙酰胺作溶剂,聚乙烯吡咯烷酮为添加剂,研究了聚醚砜(PES)质量分数对聚偏氟乙烯/聚醚砜共混膜的收缩率、水通量、截留率及形态结构的影响。聚醚砜的加入可以有效地降低共混膜的收缩率,在w(PES)=1.5%时,共混膜的水通量取得极大值,截留率取得极小值。     

壳聚糖/聚丙烯酸共聚物微球的制备及性能

以环己烷为油相,壳聚糖溶液为水相,运用反相乳液聚合法制得了具有pH敏感性的壳聚糖/聚丙烯酸共聚物微球。讨论了微球在pH=1～10缓冲溶液中的溶胀率变化,研究表明,微球在强酸性(pH≈1)和碱性(pH>7)条件下,溶胀率均在10倍以上;而在pH=2～6时溶胀较差,当pH=4时出现最低值,溶胀率低于1倍。光学显微镜所观察到的微球粒径均在40μm以内,且大小均匀。采用傅里叶红外光谱仪分析了不同配比样品特征峰的峰值和峰面积的变化。用722光栅分光光度计研究了共聚物微球包埋考马斯亮蓝的溶胀释放过程。     

静电纺丝法制备聚乙烯醇纳米纤维膜及其交联处理

用化学方法和物理方法对聚乙烯醇(PVA)纳米纤维膜进行交联处理,并且用SEM、DSC和XRD分别对不同的纳米纤维膜样品进行表征。结果表明:煅烧处理的PVA纳米纤维膜的结晶度提高,抗溶解性能良好。     

聚甲基丙烯酸甲酯包覆纳米CaCO3改性聚氯乙烯研究

研究了聚甲基丙烯酸甲酯(PMMA)包覆纳米CaCO3复合粒子填充聚氯乙烯(PVC)复合材料的加工塑化和力学性能，并与未改性纳米CaCO3的改性效果进行比较。结果发现，填充纳米CaCO3使PVC平衡扭矩和平衡熔融温度均会有所提高，填充未改性碳酸钙增加更大，填充PMMA包覆CaCO3使材料冲击性能提高的幅度大于填充未改性纳米CaCO3，而拉伸强度下降幅度较小。当PMMA包覆CaCO3填充量为8％时缺口冲击强度增加到未改性PVC的194％。冲击缺口断面形态分析表明，采用PMMA包覆CaCO3时，纳米CaCO3在PVC基体中分散均匀、团聚少。     

静电纺丝制备苯乙烯马来酸酐共聚物纳米纤维及其固定化b-D-半乳糖苷酶

采用静电纺丝技术制备苯乙烯-马来酸酐共聚物纳米纤维,最佳电纺条件为：聚合物浓度0.35 g/mL、针尖到接收板距离25 cm、电纺液流量250 mL/h、电压21 kV. 该条件下获得了直径约300 nm且分布均一的纳米纤维. 利用该纳米纤维固定b-D-半乳糖苷酶,固定化反应的最适pH值为4.0,此时酶负载量为(15.1±0.5) mg/g. 固定化酶催化2-硝基苯酚-b-D-半乳吡喃糖苷水解反应的米氏常数Km=2.7 mmol/L,略大于游离酶的Km值(2.2 mmol/L);最大反应速率Vmax为97.2 mmol/(min×mg),为游离酶的47.8%. 固定化酶在37℃下重复操作21次后活性损失仅为15%. 在连续搅拌式反应器中将固定化酶用于催化乳糖的水解反应,连续使用17 d仍能稳定运行.     

Block copolymerization of poly(diethylene glycol phthalic anhydride) and methyl methacrylate initiated by potassium diperiodatonickelate(IV)

Block copolymers of methyl methacrylate (MMA) and poly(diethylene glycol Phthalic Anhydride) (PPAG) was synthesized using a novel redox system—potassium diperiodatonickelate(IV) [DPN]/PPAG system in an alkaline medium. Block copolymers with high percentage of blocking were obtained, which indicated that DPN/PPAG redox system was an efficient initiator for this blocking. Effects of different factors on the blocking parameters were examined. The overall activation energy of this blocking was calculated to be 55.12 kJ/mol. The structure of the block copolymer was determined by infrared, X‐ray diffraction, and scanning electron microscope (SEM). A mechanism is proposed to explain the generation of radicals and the initiation of block copolymerization. The block copolymer was used as the compatibilizer in blends of PMMA and Nylon6. The SEM photographs show that the block copolymer greatly improved the compatibility of the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1312–1317, 2006     

聚丙烯酸甲酯接枝改性纳米纤维素

利用羰基二咪唑(CDI)的高活性活化纳米纤维素(NCC),使NCC表面带有高反应活性的碳碳双键。再以2-溴异丁酸乙酯为引发剂,铜丝为催化剂,制备出低分子量的聚丙烯酸甲酯(PMA)。然后采用活性自由基聚合将PMA接枝到活化的NCC表面,制备出PMA接枝改性的NCC。采用凝胶渗透色谱测定合成的PMA的分子量及分子量分布;通过傅立叶变换红外光谱及X射线衍射分析等测试方法对改性前后的NCC的结构和性能进行了分析。实验结果表明,通过单电子转移活性自由基聚合法合成的PMA分子量为2 000,分子量分布窄(分布指数为1.14),并且其成功接枝到NCC表面。     

二醋酸纤维素接枝聚甲基丙烯酸甲酯的合成与表征

以二醋酸纤维素（CDA）为接枝骨架,利用原子转移自由基聚合(ATRP)技术接枝聚甲基丙烯酸甲酯(PMMA),合成接枝共聚物(CDA-g-PMMA),采用FT-IR、1H-NMR、DSC、XRD和GPC等方法表征了CDA-g-PMMA的结构与物化性能,结果显示,支链PMMA的引入,降低了材料的熔融温度和结晶度,另外还增加了材料的韧性,ATRP方法有效的控制了共聚物相对分子质量分布系数。     

基于共混聚醚共聚酰胺的气体分离膜的制备及性能研究

聚合物共混可以制备出兼有几种聚合物特性的共混膜。为了提高气体分离膜的综合性能,以2种不同型号的聚醚共聚酰胺（具有高选择性的Pebax1657和具有高渗透性的Pebax2533）为膜材料制备了气体分离膜,并对分离膜进行结构表征、分离性能和力学性能测试。结果表明,随着Pebax2533含量的增加,聚酰胺段的链间距逐渐增大,自由体积分数增大,玻璃化转变温度降低,断裂伸长率逐渐提高;与纯Pebax1657膜相比,共混膜的CO2和N2渗透系数同时增大,N2渗透系数增加速度较快;选择性逐渐降低;与纯Pebax膜相比,两者共混后的膜的综合性能有所提高。     

超支化聚酰胺酯对聚乳酸增韧改性的研究

采用熔融共混的方法,用生物可降解的超支化聚酰胺酯(HBP)对聚乳酸(PLA)进行增韧改性,制备出具有良好韧性的PLA复合材料。对不同HBP含量的共混物的红外光谱、热性能和力学性能进行了测试和分析。红外光谱显示PLA和HBP间存在氢键作用。HBP的加入使PLA的结晶度从30.99%降低到18.58%。当HBP含量增加到10%时,PLA共混物的拉伸强度略有提高,且断裂伸长达到43.06%。结果表明:HBP的加入对PLA起到了很好的增韧作用。