聚氯乙烯/水滑石纳米复合材料热稳定性和燃烧烟密度的研究

采用十一烯酸根插层水滑石存在下的氯乙烯悬浮聚合聚氯乙烯（PVC）／水滑石纳米复合材料，研究了纳米复合材料的结构及纳米水滑石含量对复合材料热稳定性和燃烧烟密度的影响。发现原位聚合中部分氯乙烯与插层十一烯酸共聚，可实现聚合物插层；复合材料中水滑石部分剥离，分散尺寸小；随着纳米水滑石含量增加，复合材料的热失重温度和热变色时间增加，热稳定性提高；纳米水滑石对PVC具有显著的抑烟作用，当纳米水滑石含量为1．25％（质量分数）时，最大燃烧烟密度减小40％。     

聚苯胺/聚丙烯腈共混体系的流变性能研究

以三氯甲烷／二甲基亚砜混合溶剂,制备不同组成聚苯胺-十二烷基苯磺酸／聚丙烯腈(PANI-DBSA／PAN)的共混溶液。对共混溶液的流变性能进行了测试,并研究了PANI-DBSA含量对共混溶液表观粘度、非牛顿指数及结构粘度指数的关系。结果表明:PANI-DBSA含量对共混溶液的表观粘度影响比较复杂;溶液的非牛顿指数随着PANI-DBSA的增加而减小;当PANI-DBSA的质量分数高于5％时,共混溶液可纺性较差。     

插层水滑石的抑烟性能研究

使用烟密度测试箱对插层水滑石在纯乙烯-乙酸乙烯共聚物(EVAC)树脂、无卤线缆料、热塑性弹性体动态硫化橡胶(TPV)阻燃料、聚氯乙烯(PVC)阻燃料、天然橡胶复合料和三元乙丙橡胶(EPDM)复合料等高分子材料中的抑烟性能进行研究。采用烟密度对插层水滑石在不同材料中的抑烟性能进行表征,结果表明,添加1%时的EVAC树脂其最大烟密度较纯EVAC树脂降低了65%,表现出了明显的抑烟效果,但随着水滑石添加量的增大,其抑烟效果提升并不明显;添加5%时的TPV阻燃料其最大烟密度较其空白对照配方降低了41%;添加了8份的PVC阻燃料其最大烟密度较其空白对照配方降低了22.5%;但其在天然橡胶复合材料中未表现出相应的抑烟性能。     

聚氯乙烯/插层水滑石的热稳定性和力学性能

马来酸和水滑石(MgAl-CO3LDHs)反应制备马来酸根插层水滑石(MgAl-maleate LDHs),X射线衍射和红外光谱分析表明马来酸根已插层水滑石层间。把插层有马来酸根的水滑石填充聚氯乙烯(PVC),研究马来酸根插层水滑石对PVC热稳定性和力学性能的影响。结果表明:水滑石层间的马来酸根中的双键和PVC降解产生的C=C共轭双键发生Alder-delies加成反应,PVC的初期色泽得到改善,但PVC的长期热稳定性稍有降低;同时,插层改性后的水滑石改善了PVC和水滑石之间的相容性,提高了PVC的力学强度。     

头孢吡肟插层水滑石的缓释性能

用共沉淀法将头孢吡肟(Cefepime)插层到含NO3–的Zn–Al水滑石(layered double hydroxides,LDHs)层间,组装得到杂化材料Cefepime-LDHs。X射线衍射结果表明:Cefepime-LDHs晶型良好,为典型的水滑石类层状材料,其层间距为2.18 nm。通过对Cefepime三维尺寸的理论模拟,推测该杂化材料中的Cefepime以沿长轴方向与层板呈一定角度倾斜的方式排布于水滑石层间。此外,与Cefepime相比,该杂化材料中层间药物的释放具有一定的缓释效果,缓释过程符合一级动力学及Higuchi扩散模型。     

纤维素与聚丙烯腈共混纤维的结构与性能

纤维素与聚丙烯腈溶液共混后纺丝成纤得到改性纤维。含纤维素组分多的共混纤维具有腈纶手感,良好的机械性能。用X射线衍射研究共混纤维发现,纤维素与聚丙烯腈的晶体结构同存,各纤维的结晶程度及取向度相差较小。共混纤维的扫描电镜结果表明,含纤维素多的共混纤维中,纤维素为连续相,聚丙烯腈为分散相;纤维素微纤分布于整个纤维中。含聚丙烯腈多的共混纤维中,聚丙烯腈为连续相,纤维素为分散相,两组分之间结构分离。     

原位聚合法制备聚丙烯腈/蒙脱土插层共混材料初探

用十六烷基三甲基溴化铵(CTAB)对蒙脱土进行有机化处理,以过硫酸铵为引发剂,使丙烯腈单体在有机化蒙脱土层间进行原位聚合.对这种插层复合材料的的燃烧性能和热性能进行了初步研究,并且用红外光谱和X射线衍射对其结构进行了分析与表征.结果表明:PAN/MMT共混复合物的阻燃性能有一定提高,其极限氧指数从18%提高到了22%;耐热性能得到一定程度改善.红外光谱和X射线衍射分析结果显示:在蒙脱土片层之间通过原位聚合生成了聚丙烯腈大分子,使蒙脱土层间距有一定程度的增大.     

聚苯胺/聚丙烯腈导电复合材料的研究

以过硫酸铵为氧化剂 ,研究了苯胺在聚丙烯腈纤维表面的原位聚合反应制备聚苯胺 /聚丙烯腈导电复合材料的条件。确定了最佳工艺条件 :氧化剂的用量 0 2mol/L、苯胺的浓度 0 1～ 0 3mol/L ,掺杂酸以对甲苯磺酸为最好。聚苯胺 /聚丙烯腈导电复合材料的质量比电阻在 10 4～ 10 5Ω·g/cm2 范围 ,聚苯胺树脂在聚丙烯腈纤维表面呈颗粒分布 ;与聚丙烯腈原纤维材料相比 ,复合材料的断裂强度略有降低 ,而断裂伸长率基本不变     

碳纳米管/聚丙烯腈复合纤维的制备及结构研究

通过原位聚合的方法制备了碳纳米管/聚丙烯腈(CNTs/PAN)聚合液,用湿法纺丝工艺制备了CNTs/PAN复合纤维,分析了复合纤维流变性能、热性能及截面形貌。结果表明:CNTs的加入使得聚合物溶液出现了假凝胶化,粘度和弹性均有所上升,纺丝时溶液细流的表层遇水迅速凝固成致密的皮层,影响了纤维芯部的二甲基亚砜(DMSO)和水的双扩散作用,凝固丝出现了很明显的皮芯结构,CNTs的加入还使得纤维预氧化放热过程得到了缓和。     

水滑石在阻燃聚丙烯腈纤维改性中的应用研究

在经十二烷基硫酸钠柱撑的水滑石层间进行丙烯腈的原位聚合反应，用红外光谱和X-射线衍射对聚合物样品进行了结构分析与表征，并对聚丙烯腈／柱撑水滑石共混物样品的燃烧性能进行了研究。结果表明：丙烯腈单体在水滑石片层之间发生原位聚合反应，生成聚丙烯腈大分子，并使水滑石片层间距有一定程度的增大；共混物的极限氧指数从18．1％提高到了25．5％，同时共混物的热重曲线向高温方向发生了偏移，阻燃性能得到一定程度改善。     

Enhanced Ionic Conductivity in Poly(ethylene oxide)/Layered Double Hydroxide Nanocomposite Electrolytes

All solid-state poly(ethylene oxide) (PEO) nanocomposite electrolytes were made containing nanoscale fillers of layered double hydroxides (LDHs). Two kinds of oligo(ethylene oxide) modified LDHs were prepared by template method, and added into PEO/LiClO₄ matrix (with EO/Li molar ratio of 8) to study the effect on the ionic conductivity of PEO/LDH nanocomposite electrolytes. The structures of the modified LDHs were characterized by infrared spectra, thermogravimetric analysis and wide-angle X-ray diffraction. The results show that the oligo(ethylene oxide) with phosphonate anion can be effectively intercalated into the gallery region of LDHs and formed as an organic-inorganic hybrid (PLDH). With enhanced compatibility of LDH sheets by oligo(ethylene oxide) surface modification, the PEO/PLDH nanocomposite exhibits fully exfoliation morphology. The well dispersed LDH layers in PEO/LiClO₄/PLDH nanocomposite electrolytes rendering the formation of amorphous phase, results in an enhancement of ionic conductivity by three orders of magnitude compared to the pure PEO/LiClO₄ polymer electrolyte. This novel nanocomposite electrolytes system with high ionic conductivity will be benefited to fabricate the thin-film type of Li-polymer secondary battery. This revised version was published online in July 2006 with corrections to the Cover Date.     

催化领域中水滑石类层柱材料的技术现状及国内专利分析

文章简述了水滑石类层柱材料在催化领域的应用,从专利申请量年度分布情况、申请人类型统计和申请人排名情况三个方面进行统计分析,通过对数据的比较和分析,得出了我国水滑石类层柱材料在催化领域的研究现状、应用水平和研究趋势。     

氢氧化铝微粉表面原位组合化学改性的研究

利用黏度法研究了以金属偶联剂[M(OR)n]和9种不同链长与构型的含羧基或羟基有机物对氢氧化铝表面进行原位组合化学改性的效果。研究表明:具有柔性链基结构的改性剂和金属偶联剂组合改性的效果较好;在液体石蜡中改性氢氧化铝最大填充量由未改性时的43%提高到了改性后的62%,体系黏度才大幅度增加。     

Facile fabrication of spherical architecture of Ni/Al layered double hydroxide based on in situ transformation mechanism

Spherical architectures of nickel–aluminum layered double hydroxide (NiAl‐LDH) with hydrotalcite‐like nanoflakes as building blocks were facilely fabricated by precipitation reaction in aqueous solution without any surfactants and organic solvents. Growth of such unique structure undergoes preorganization of primary nanospheres of colloidal amorphous aluminum hydroxide (AAH) in solution, followed by nucleation and crystallizaion of LDH from exterior to interior of AAH spheres by an in situ transformation mechanism. The structure and morphology of LDH spheres depend on both starting raw materials and synthetic parameters including reaction time, reaction temperature, and aqueous ammonia dosage. NiAl‐LDH sphere as positive electrode material delivers improved rechargeable and discharge capacity, with the highest discharge capacity of 173 mAh g^?1 at a current density of 30 mA g^?1 within a potential range from ?0.1 to 0.45 V in 10 mol L^?1 KOH solution, due to the faster diffusion processes in the spherical architecture than the powder sample. © 2014 American Institute of Chemical Engineers AIChE J 60: 4027–4036, 2014     

氧化铁/层状双金属氢氧化物复合材料的制备

制备由不同结构单元组成的复合材料是提高材料性能的一种有效方法.分别采用两种方式(双滴共沉淀法和LDHs层板附着生长法)制备Fe3 O4/层状双金属氢氧化物(LDHs)复合材料.利用X-射线衍射、电子显微分析和红外光谱等测试方法研究了LDHs和Fe3 O4的复合方式对复合材料形貌、粒径和结晶性能的影响.同时对比分析了两种制备方案得到的Fe3OJLDHs复合材料生长规律.实验结果表明,采用双滴共沉淀法制备的Fe3OJLDHs复合材料具有层状结构和良好的结晶性.     

镁-铝类水滑石的摩擦性能

以菱镁矿为原料,通过化学分解--水热法合成镁铝类水滑石,利用月桂酸钠对合成样品进行表面改性,以提高类水滑石粉体在润滑介质中的分散性。月桂酸钠的最佳添加量占浆液质量5%。分别采用微振动(SRV)摩擦实验和四球摩擦实验表征改性类水滑石粉体的摩擦性能。结果表明:类水滑石粉体作为减摩材料,其合理的添加量为30g/L基础油。类水滑石粉体可显著降低摩擦副间的摩擦系数,是一种具有潜在应用价值的减摩材料。     

New Nanocomposites Based on Syndiotactic Polystyrene and Organo-Modified ZnAl Layered Double Hydroxide

New nanocomposites were prepared by mixing syndiotactic polystyrene (sPS) with organo-modified ZnAl layered double hydroxide (O-ZnAl-LDH) in toluene solution. Both wide-angle X-ray diffraction (WXRD) and transmission electron microscopy (TEM) examinations confirmed the nanocomposite formation with exfoliated or intercalated O-ZnAl-LDH distributed in the sPS matrix. Meanwhile, the nonisothermal crystallization behavior of the resulting nanocomposites was studied using differential scanning calorimetry (DSC) technique at various cooling rates. The results indicated that the O-ZnAl-LDH particles in nanometer size might act as nucleating agents and accelerate the overall nonisothermal crystallization process.     

Preparation and Properties of ZnAl Layered Double Hydroxide/Polycaprolactone Nanocomposites for Use in Drug Delivery

ZnAl-layered double hydroxides (ZnAl-LDH)/polycaprolactone (PCL) nanocomposites were prepared by solution intercalation method. It is shown that lamellar ZnAl-LDH is randomly distributed in the PCL matrix with diameter of 60 nm. The addition of ZnAl-LDH decreases thermal decomposition temperature of composites, but improves the elastic modulus and tensile strength. The weight loss and release amount of diclofenac of ZnAl-LDH/PCL composites are higher than that of neat PCL. The drug release kinetics for nanocomposites and neat PCL could be described by first-order kinetic and Ritger-Peppas kinetic model.