壳聚糖/累托石纳米复合材料的结构与性能

采用溶液插层法制备了不同累托石含量的壳聚糖/累托石纳米复合材料,研究了累托石含量、层间距对复合材料性能的影响及不同累托石含量的复合材料的热稳定性和抗菌性能.结果表明:壳聚糖分子链插层进入了累托石层间,累托石均匀地分布在壳聚糖基体中;纳米复合材料的性能与累托石的含量和层间距密切相关,当壳聚糖与累托石的质量比为12∶1时插层效果最好;壳聚糖/累托石纳米复合材料的抗菌能力比单一壳聚糖优异,尤其是对革兰氏阳性菌,其抑菌的最小浓度为单一壳聚糖的1/4～1/2,抑菌时间是单一壳聚糖的3～5倍;复合材料对革兰氏阳性菌的抑制作用比对革兰氏阴性菌的强,且随着累托石含量的增加及层间距的增大,抗菌性能越来越强;纳米复合材料的热稳定性优于壳聚糖.     

甲壳三糖-g-壳聚糖/累托石纳米复合材料作为基因载体的研究

本文合成了甲壳三糖-g-壳聚糖（TCS），并与累托石插层复合制备纳米复合材料，采用XRD和TEM对其进行了表征。粒径分析结果表明，两种分子量的TCS与pDNA复合物的粒径大小都在75nm左右，而累托石加入后，其粒径都不同程度的增加，最大达到191nm。在PBS中的聚集动力学及琼脂糖凝胶电泳实验发现，高分子量TCS /pDNA复合物较低分子量复合物稳定，而累托石的加入降低了其稳定性。体外转染实验初步表明，甲壳三糖-g-壳聚糖/累托石-DNA复合物能介入肝癌细胞中并表达荧光。该纳米复合材料可作为潜在的非病毒基因载体。     

单分散聚苯乙烯/二硫化钼纳米复合微球的制备与分散性

以二硫化钼为核,聚苯乙烯为壳,通过种子乳液聚合方法,成功制备了具有核壳结构的聚苯乙烯/二硫化钼(PS/MoS2)有机-无机纳米复合微球。利用紫外可见吸收光谱、透射电镜、扫描电镜、能量色散谱仪等多种方法,对PS/MoS2纳米微球的形貌、结构进行了表征,同时,利用分散性试验考察了PS/MoS2纳米微球在油溶性单体双环戊二烯(DCPD)中的分散性。试验结果表明:聚苯乙烯包覆在MoS2的表面,形成核壳结构;纳米粉体呈球形且粒径尺寸均一。分散性试验表明PS/MoS2纳米微球在DCPD中具有极佳的分散性。     

Enhanced performance of nano-sized SiC reinforced Al metal matrix nanocomposites synthesized through microwave sintering and hot extrusion techniques

In the present study, nano-sized SiC (0, 0.3, 0.5, 1.0 and 1.5 vol%) reinforced aluminum (Al) metal matrix composites were fabricated by microwave sintering and hot extrusion techniques. The structural (XRD, SEM), mechanical (nanoindentation, compression, tensile) and thermal properties (co-efficient of thermal expansion- CTE) of the developed Al-SiC nanocomposites were studied. The SEM/EDS mapping images show a homogeneous distribution of SiC nanoparticles into the Al matrix. A significant increase in the strength (compressive and tensile) of the Al-SiC nanocomposites with the addition of SiC content is observed. However, it is noticed that the ductility of Al-SiC nanocomposites decreases with increasing volume fraction of SiC. The thermal analysis indicates that CTE of Al-SiC nanocomposites decreases with the progressive addition of hard SiC nanoparticles. Overall, hot extruded Al 1.5 vol% SiC nanocomposites exhibited the best mechanical and thermal performance as compared to the other developed Al-SiC nanocomposites.     

Effects of Hydrophilic Monomer Types and Level on Polystyrene-Acrylate/montmorillonite Nanocomposite Made by Emulsion Polymerization

1 Results Nanocomposite has attracted more and more interest all over the world.Polystyrene (PS) is a commercialized and mass-productive polymer,continuous research efforts have been devoted to the development of polystyrene/montmorillonite (PS/MMT) nanocomposites[1-2].But the polarity of styrene (St) is too small to intercalate the space between the clay layers.The polarity of hydrophilic monomer is so strong that it can intercalate the MMT easily,the intercalated smectic clays maybe exfoliated by usin...     

碳纳米管对聚苯乙烯分子运动的影响

利用DSC、流变仪和能量损耗仪等测试仪器,系统研究了碳纳米管加入到聚苯乙烯基体中后对不同长度聚苯乙烯分子链运动的影响.结果表明,碳纳米管加入到聚苯乙烯中后对聚苯乙烯的玻璃转变和液-液转变都产生了影响.碳纳米管的加入引起自由体积的增加只在一个很小的范围内影响了分子链段的运动,当质量分数为0.1%的碳纳米管加入时,链段运动速度增加,玻璃转变温度明显向低温方向移动;而由于范德华力的存在,高分子链会在碳纳米管表面选择吸附,从而使得整链运动时,参与运动的链单元尺寸降低,所以造成了整链运动时链间的耦合降低了.     

壳聚糖/酸化蛭石纳米复合材料的制备与表征

以可生物降解材料壳聚糖为基体,制备了一系列不同比例的壳聚糖/酸化蛭石(HVMT)纳米复合材料.WAXD和TEM试验结果表明HVMT可以有效剥离并分散在壳聚糖基体中形成剥离型纳米复合材料.与壳聚糖相比,纳米复合材料的热性能随着酸化蛭石含量的增加有明显提高,在蛭石含量仅为2%的情况下,材料的T<,-10%>增加了141℃.     

有机累托石/环氧树脂纳米复合材料制备及其流变性能研究

采用自制离子液体型累托石,用熔融插层法制备有机累托石/环氧树脂/桐油酸酐纳米复合材料。分别用XRD、DSC、旋转流变仪对复合材料的微观结构、固化动力学和流变性能进行测试。结果表明,有机累托石含量较低时在环氧树脂基体中形成了剥离型纳米复合材料;有机累托石的加入,降低了环氧树脂/桐油酸酐体系固化反应的活化能和频率因子,但环氧树脂/桐油酸酐体系的固化反应不是简单的一元反应,有机累托石的加入并不改变其固化反应机理;随着有机累托石含量的增加,环氧树脂/桐油酸酐体系的黏流活化能逐渐增大。     

Preparation of polystyrene/ SiO2 nanocomposites by surface-initiated nitroxidemediated radical polymerization

As nanoscopic science, technology, and engineering have been rapidly developed in recent years, nanomate- rials have attracted widespread attention for their spe- cific capability in the optics, electrics, calorifics, mag- netics, catalysis and mechanics …     

聚苯乙烯改性纤维素纳米晶体对聚甲基丙烯酸甲酯热稳定性的增强作用

采用原子转移自由基聚合(SI-ATRP)在纤维素纳米晶体(CNC)表面接枝聚苯乙烯,并利用傅里叶红外光谱(FTIR)、热重分析仪(TGA)对改性前后的纤维素纳米晶体的化学结构和热稳定性进行了研究。测试结果表明,聚苯乙烯可成功地接枝到纤维素纳米晶体的表面; 纤维素纳米晶体的热分解温度由150 ℃上升到220 ℃,改性后纤维素纳米晶体的热稳定性得到提高。采用溶液浇铸法制备聚甲基丙烯酸甲酯/纤维素纳米晶体复合材料(PMMA/CNC),并利用TGA、透光率测试对复合材料热稳定性和透光率进行了研究。结果表明,当温度达到350 ℃时,PMMA/CNC的热分解温度比纯PMMA提高了近150 ℃, CNC的加入量为1%时,复合材料的透光率为89%,接近纯PMMA的透光率(91%)。聚苯乙烯改性纤维素纳米晶体可用于在保持PMMA透明性的前提下更好地改善PMMA复合材料的热稳定性。     

Preparation and characterization of poly（styrene／maleic anhydride）／kaolin nanocomposites

The direct exfoliation of in situ intercalative copolymerized styrene/maleic anhydride charge-transfer-complex (PSMA) into the inter lamellar spaces of modified kaolin (Kao-DMSO), which was intercalated and surface modified by dimethyl sulfoxide (DMSO), was reported. The nano structure of the composites was investigated by wide-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM). The interaction between kaolin surface and PSMA chain was conformed by FTIR analysis.The XRD results showed that the intercalated polystyrene-maleic anhydride units were arranged in the flattened monolayer arrangements, and the 001 diffraction peak of the original kaolin disappeared. The TEM image showed that thekaolin was exfoliated into nanometer size and dispersed in the polymer matrix. Additionally the thermal stability of the nanocomposites was studied by thermo-gravimetric analysis(TGA), and the resulting thermogram indicated that the thermal stability of the nanocomposites was significantly increased.     

聚碳酸酯多孔增透膜的制备及性能研究

将聚碳酸酯(PC)与聚苯乙烯(PS)进行溶液共混后旋涂成膜(spin-coating),然后利用共混薄膜在成膜后期及热处理过程中会产生相分离的特点,采用溶剂抽提技术,将薄膜中的PS组分去掉来制备聚碳酸酯基多孔增透膜,并通过改变两高分子组分间的质量比及溶液浓度来调节薄膜的增透效果.由紫外-可见分光光度计的测试结果可知:在二氯甲烷溶剂(3 wt%)中,PC/PS=70/30(w/w)条件下形成的PC多孔膜,其最大透过率可达到96%以上,此外该薄膜还具有聚碳酸酯材料的优良力学性能及热稳定性等优点,是一种很有应用前景的薄膜材料.     

高分子溶液气液平衡的测定与关联

采用静态蒸气吸收法测定了在308.15K时苯，甲苯与聚乙烯（PS），聚甲基丙烯酸甲酯（PMMA），聚醋酸乙烯酯（PVAc)构成的6个单溶剂-高分子系统的气液平衡数据，用UNIQUAC活度系数模型和链状流体状态方程对实验数据进行了关联。     

Chemical,mechanical, and thermal expansion properties of a carbon nanotube-reinforced aluminum nanocomposite

In the present study, the chemical and mechanical properties and the thermal expansion of a carbon nanotube (CNT)-based crystalline nano-aluminum (nano Al) composite were reported. The properties of nanocomposites were tailored by incorporating CNTs into the nano Al matrix using a physical mixing method. The elastic moduli and the coefficient of thermal expansion (CTE) of the nanocomposites were also estimated to understand the effects of CNT reinforcement in the Al matrix. Microstructural characterization of the nanocomposite reveals that the CNTs are dispersed and embedded in the Al matrix. The experimental results indicate that the incorporation of CNTs into the nano Al matrix results in the increase in hardness and elastic modulus along with a concomitant decrease in the coefficient of thermal expansion. The hardness and elastic modulus of the nanocomposite increase by 21% and 20%, respectively, upon CNT addition. The CTE of CNT/Al nanocomposite decreases to 70% compared with that of nano Al.     

机械合金化法制备的Cu/SiC纳米复合材料的组织、热性能和力学性能评估

Nano-sized silicon carbide (SiC: 0wt%, 1wt%, 2wt%, 4wt%, and 8wt%) reinforced copper (Cu) matrix nanocomposites were manufactured, pressed, and sintered at 775 and 875°C in an argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy were performed to characterize the microstructural evolution. The density, thermal expansion, mechanical, and electrical properties were studied. XRD analyses showed that with increasing SiC content, the microstrain and dislocation density increased, while the crystal size decreased. The coefficient of thermal expansion (CTE) of the nanocomposites was less than that of the Cu matrix. The improvement in the CTE with increasing sintering temperature may be because of densification of the microstructure. Moreover, the mechanical properties of these nanocomposites showed noticeable enhancements with the addition of SiC and sintering temperatures, where the microhardness and apparent strengthening efficiency of nanocomposites containing 8wt% SiC and sintered at 875°C were 958.7 MPa and 1.07 vol%?1, respectively. The electrical conductivity of the sample slightly decreased with additional SiC and increased with sintering temperature. The prepared Cu/SiC nanocomposites possessed good electrical conductivity, high thermal stability, and excellent mechanical properties.     

反应性单体改性PP/PS共混物的增容作用

制备了聚丙烯/聚苯乙烯(PP/PS)共混物和反应性单体苯乙烯(St)、丙烯酸(AA)及其混合单体改性PP/PS共混物,用扫描电镜(SEM)、偏光显微镜(POM)和动态黏弹谱仪(DMA)研究了反应性单体改性PP/PS共混物的相形态与动态力学行为.结果表明反应性单体St存在增容作用,促进PS在PP中的分散,使分散相PS的粒子尺寸减小.反应性单体AA存在明显的异相成核作用,使PP的球晶尺寸降低.St改性共混物的增容作用比AA改性共混物的明显,而AA改性共混物的异相成核作用比St改性的大.     

轻型建筑外保温材料──PS废料的再生与利用

本文叙述了一种新型的技术──废弃聚苯乙烯（ＰＳ）的再生法，作为粘合剂和填补剂首先制成聚丙烯酸乳液，然后，再将该乳液掺合ＰＳ泡粒得到各种隔热保温材料。作为轻型的绝热外层涂装及内灌浆材料，此方法对建筑业颇具意义。     

细乳液原位聚合法制备聚苯乙烯非共价修饰的碳纳米管

用细乳液原位聚合方法合成了聚苯乙烯/碳纳米管复合乳液,在用于聚合的单体中加入5%的交联剂二乙烯苯,使得部分聚苯乙烯通过交联缠绕固定在碳纳米管表面.乳液中碳纳米管表面负载有聚苯乙烯纳米微球或纳米薄膜.破乳后得到的复合材料在除去游离态的聚苯乙烯后,仍有部分聚合物因交联缠绕作用而存在于碳纳米管表面,使碳纳米管可均匀地分散于甲苯溶剂中.该方法解决了非共价修饰中聚合物和碳纳米管之间的结合力问题.     

STUDIES ON THE COMPATIBILITY OF PPO MULTI-COMPONENT BLENDS

The compatibility and phase morphology of poly (phenylcne oxide) (PPO) multi-componenet blends with poly (ethylene terephthalate) (PET) and polystyrene (PS) were studied using differentialscanning calorimetry (DSC), dynamic mechanical analysis (DMA) and scanning electron microsopy (SEM) methods. The effect of glycidyl methacrylate-styrene copolymer (GMS), as a compatibilizer, on the morphology of the PPO blends has also been studied in detail. The influence of the moiecular weight of PET and the synergetic effect of the compatibilizers of GMS and phenoxy on the morphology were examined. The DSC and DMA results show that there are two distinct glass transitions correspondinig to PET and PPO existed, however, the Tg of PPO shifts toward lower temperature region due to the addition of GMS and PS. The SEM results reveal that PET component is as dispersed phases in the PPO matrix, part of which is located at the interfaces due to the interaction with GMS while PS is miscible in the PPO matrix. A significant     

Preparation and characterization of three-dimen-sionally ordered macroporous polystyrene via atom-transfer radical polymerization

Three-dimensionally ordered macroporous polystyrene(3DOM PS) with pore size of 350 nm was fabricated using Cp2Co/Ethyl 2-bromoisobutyrate(EBiB) catalytic system by ATRP.The resulting polymers were detected by FT-IR,1H-NMR,SEM,and GPC.The microstructure of 3DOM PS was confirmed by FT-IR and 1H-NMR.SEM micrographs show that both silica spheres within the templates and pores in the 3DOM polystyrene are arranged in highly ordered fashion,and the shrinkage of the pores in the 3DOM PS is 24%.GPC curves show that the 3DOM PS possesses slightly lower Mn and narrow MWD compared with bulk one.This result indicats that living polymerization is different from non-living polymerizationin in the confined space.