超声波场下相分离法制备SiO_2/PA6复合粒子

在PA6的甲酸溶液中加入经表面处理的SiO2粒子,然后采用滴加非溶剂法和冷却降温法相结合的相分离法促使PA6粒子成型,同时在相分离及分散过程中引入超声波场,制备出SiO2/PA6复合粒子。通过对SiO2/PA6复合粒子的结构表征,发现SiO2/PA6复合粒子形状不规整,表面凹凸不平,SiO2粒子除了被PA6粒子大量包裹外还,有一小部分分布于PA6粒子的表面。以理论添加量为20%计算,SiO2的包覆率为74.2%。     

超声波场下原位分散聚合反应制备Ag／PS复合粒子的影响因素

纳米银／聚苯乙烯（Ag／PS）复合粒子是一种新型的功能粒子,有效利用昂贵金属纳米粒子组元的独特性能,可实现高表面能金属纳米粒子稳定化的目的。在Ag／PS复合粒子的制备过程中,表面活性剂种类及用量、Ag粒子表面特性及用量、反应体系组成（单体用量、引发剂用量及稳定剂用量）等均对Ag／PS复合粒子形态、粒径大小及分布有一定的影响。通过对各影响因素的研究,确定了优化的配方,即要实现苯乙烯（St）对大部分纳米Ag粒子的包覆（复合率〉50%）,且复合粒子形态和分散性较好,SDS的用量应控制在Ag粒子用量的5％以内,Ag的用量应控制在单体用量的10％以内。     

超声波引发苯乙烯分散聚合反应制备SiO2/PS复合粒子

在系统研究超声波场下辅助引发苯乙烯(St)分散聚合反应规律的基础上,利用超声波的分散、粉碎、活化、引发等多重作用,在实现纳米SiO2粒子于反应介质中均匀分散的同时,引发St单体在纳米SiO2粒子表面进行分散聚合反应,制备出二氧化硅/聚苯乙烯(SiO2/PS)复合粒子,并运用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、红外光谱(FTIR)、热重分析(TGA)、X射线衍射谱(XRD)及X射线光电子能谱(XPS)等多种测试手段对SiO2/PS复合粒子的形貌、粒径及分布、表面特性、化学组成及结构等进行了表征。     

Ag/PMMA复合粒子的制备及表征

纳米银/聚甲基丙烯酸甲酯(Ag/PMMA)复合粒子是一种新型的功能粒子,可以有效利用昂贵金属纳米粒子组元的独特性能,是高表面能金属纳米粒子稳定化的有效途径.本文首先在超声波场中用表面活性剂SDS对纳米Ag粒子进行亲油化处理,然后在N<,2>保护下利用超声波的分散、粉碎、活化、引发等多重作用,在实现纳米Ag粒子在反应介质...     

相分离法制备尼龙粒子的影响因素研究

采用相分离法对尼龙溶液在发生相分离过程中的影响因素进行了研究.包括聚合物溶液浓度、凝聚剂的用量及加入速度、分散稳定剂的用量、搅拌速度等,获得了较优的制备工艺条件.所制备的尼龙粒子分布较均匀,表面粗糙,存在较多孔洞,粒子与粒子之间的分散性较好,无相互粘连现象.     

乳液聚合法制备碳酸钙/聚苯乙烯复合粒子

将苯乙烯 ( St)在 Ca CO3 粒子水相悬浮液中进行无皂乳液聚合 ,实现了 PSt对 Ca CO3 粒子的包覆。通过复合粒子 ξ电位及水相分散性能测试证明了 Ca CO3 粒子表面 PSt的存在 ;以苯为溶剂 ,复合粒子经索氏提取器抽提 2 4h后的结果表明 ,PSt在 Ca CO3 粒子表面包覆量为 Ca CO3 重量的 6.4%     

综合相分离法制备聚酰胺6粒子的研究

首先采用滴加非溶剂法和冷却降温法分别制备了聚酰胺6（PA6粒子）,结果表明,前者制备的PA6粒子表面结构疏松,但粒子之间分散性好,而后者制备的PA6粒子表面结构致密,但粒子之间分散性差。然后将滴加非溶剂法和冷却降温法相结合,提出了综合相分离法,采用此方法制备的PA6粒子粒径分布较均匀,粒子与粒子之间分散性好,表面仍有孔洞但结构比较致密。     

超声波化学共沉淀法制备SiO_2/Fe_3O_4复合粒子

为了防止纳米级Fe3O4的氧化及团聚,在其表面包覆一层二氧化硅,本文设计了Si O2/Fe3O4复合粒子的制备工艺。本论文采用的制备方法是超声波化学共沉淀法,用X-射线衍射仪(XRD)、扫描电镜(SEM)、傅里叶红外转换光谱(FTIR)、低温氮吸附比表面积测试仪等研究了粒子晶相、组织形貌及化学键。结果表明,Si O2/Fe3O4复合粒子形貌为球形,表面具有孔隙,颗粒平均尺寸约250 nm。Si O2/Fe3O4复合粒子不仅具有良好的化学稳定性和生物相容性,而且为下一步表面修饰打下坚实的基础。     

粒子表面处理对纳米Ag/PMMA复合粒子的影响

纳米银/聚甲基丙烯酸甲酯(Ag/PMMA)复合粒子是一种新型的功能粒子,可以有效利用昂贵金属纳米粒子组元的独特性能,是高表面能金属纳米粒子稳定化的有效途径。在Ag/PMMA复合粒子的制备过程中,纳米Ag粒子表面处理时所用表面活性剂的种类及用量直接影响Ag/PMMA复合粒子的粒径及分布。纳米Ag粒子在超声波场作用下经十二烷基硫酸钠(SDS)处理后,可在纳米Ag粒子表面形成单体和引发剂的富集区,在适当条件下引发以纳米Ag粒子为核心的原位分散聚合反应。本文通过对各影响因素的研究,采用阴离子表面活性剂SDS对纳米Ag粒子进行表面处理,且用量控制在Ag粒子质量的10%～15%范围内,可实现Ag粒子的PMMA有机包覆。     

基于乳液聚合法制备无机纳米粒子/聚合物复合粒子及其应用研究进展

综述了国内外通过乳液聚合制备聚合物包覆无机纳米复合粒子的方法及包覆效果,包括纳米SiO2/聚合物、CaCO3/聚合物、TiO2及其他无机粒子/聚合物,介绍了复合粒子的形成机理及其在电极材料、阻燃和感光树脂中的应用,并对其前景作了展望。     

还原法制备二氧化硅/银复合粒子

以球形纳米二氧化硅、硝酸银为原料,通过化学还原法制备了二氧化硅/银复合粒子。探讨了还原剂、硝酸银添加量、反应时间、反应温度等对二氧化硅载银粒子载银量的影响规律。采用原子吸收光谱测定法（AAS）和X射线衍射（XRD）分析,对产物的含银量、晶型及平均粒径进行表征。结果表明：取0.5 g球形纳米二氧化硅,在硝酸银浓度为3×10-2 mol/L、硝酸银乙醇溶液添加量为20 mL、反应温度为30 ℃、反应时间为2 h、乙醛为还原剂的条件下,获得的二氧化硅载银粒子的载银量为10.6%（质量分数）。     

超声辐照聚合制备复合乳液—影响反应的几个因素

以V-50为引发剂采用超声辐照乳液聚合制备PMMA／nano-ZnO复合乳液。引发剂用量、乳化剂用量、乳化剂配比、纳米氧化锌的性质、用量以及反应温度、单体含量是本体系超声辐照聚合反应的重要影响因素。这些参数的不同导致了聚合反应的诱导期、转化率不同。含有纳米氧化锌的乳液聚合体系,纳米氧化锌影响了聚合过程中的成核,有未改性纳米氧化锌参与的聚合体系的主要成核方式仍然是胶束成核与均相成核。     

反相微乳液法制备纳米银/羧甲基壳聚糖复合微粒

采用反相微乳液法,以水合肼为还原剂制备纳米银/羧甲基壳聚糖复合微粒,并用红外光谱、X射线衍射、透射电镜对制备的样品微粒进行表征,讨论了搅拌速度、AgNO_3用量以及乳液体系的组成对纳米银复合粒子形貌与尺寸的影响。结果表明,当搅拌速度为1400r/min,AgNO_3用量为0.52g,吐温-80/液体石蜡体积比为4:5时,可制得粒径在50nm左右的纳米银/羧甲基壳聚糖复合微粒,且粒子具有较好的面心立方晶体结构。     

Preparation of GaP/RhB nanocomposite by ultrasonic irradiation

The GaP/rhodamine B (RhB) nanocomposite was synthesized by ultrasonic irradiation method and characterized by transmission electron microscope, Fourier transformation infrared spectroscopy and Raman spectroscopy. The results show that the morphology of GaP/RhB nanocomposite changed from “superlattice” to asymmetric core-shell and finally to symmetric core-shell microstructure with the extending of irradiation time. The possible reason for the changing of morphology of GaP/RhB nanocomposite was investigated.     

Preparation of thermoplastic polyurethane/graphene oxide composite scaffolds by thermally induced phase separation

In this study, biomedical thermoplastic polyurethane/graphene oxide (TPU/GO) composite scaffolds were successfully prepared using the thermally induced phase separation (TIPS) technique. The microstructure, morphology, and thermal and mechanical properties of the scaffolds were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and compression tests. Furthermore, NIH 3T3 fibroblast cell viability on the porous scaffolds was investigated via live/dead fluorescent staining and SEM observation. FTIR and Raman results verified the presence of GO in the composites. SEM images showed that the average pore diameter of the composite scaffolds decreased as the amount of GO increased. Additionally, the surface of the specimens became rougher due to the embedded GO. The compressive modulus of composite specimens was increased by nearly 200% and 300% with the addition of 5% and 10% GO, respectively, as compared with pristine TPU. 3T3 fibroblast culture results showed that GO had no apparent cytotoxicity. However, high loading levels of GO may delay cell proliferation on the specimens. POLYM. COMPOS., 35:1408–1417, 2014. © 2013 Society of Plastics Engineers     

超声雾化法制备单分散纳米CeO_2粉体研究

以硝酸铈和碳酸氢铵为原料,使用超声双雾化工艺实现微区反应制备了纳米CeO2粉体,并利用透射电子显微镜、X射线衍射分析和红外光谱测试等手段对制备的纳米CeO2粉体的物相结构、形貌及颗粒大小进行了表征,并探讨了超声雾化工艺制备纳米颗粒的反应机理。结果表明,超声雾化工艺所制备的纳米CeO2粉体粒径为3—5 nm,粒度分布均匀,且单分散性好;溶剂中加入的表面活性物质有利于降低雾化液的表面张力,使雾化液滴细化,并且具有一定的空间位阻作用,可以明显改善颗粒间的团聚。     

超声波辐射相转移催化合成十二烷基缩水甘油醚

超声波辐射下三乙基苄基氯化铵相转移催化由十二醇与环氧氯丙烷合成十二烷基缩水甘油醚,产品用FT-IR进行结构表征。考察了催化剂的种类、反应物的摩尔比及其与催化剂和NaOH的摩尔比、超声波辐射功率和辐射时间等因素对产品收率的影响。结果表明,超声波辐射下,三乙基苄基氯化铵具有良好的催化活性,较佳反应条件为:十二醇0.15 mol,n(十二醇):n(环氧氯丙烷):n(三乙基苄基氯化铵):n(NaOH)=1:1.15:0.05:1.05,甲苯15 mL,超声波辐射功率100 W下辐射45 min,此时产品的收率达到93%以上。     

Preparation of PVDF/CaCO3 composite hollow fiber membrane via a thermally induced phase separation method

The spinnabiliy of polyvinylidene fluoride (PVDF)/CaCO₃ microparticle dope solution were explored via a thermally induced phase separation process, and composite hollow fiber (CHF) membranes were prepared successfully. The experiment results showed that the self‐supporting property of CHF got improved after adding CaCO₃ at low concentration of PVDF, so the control of spinning process became easy. The effects of CaCO₃ on the structure and properties of hollow fiber membrane were investigated in terms of morphology, water flux, porosity, breakage strength, and crystallization. The results indicated that CHF presented a uniform bicontinuous structure. The permeability and porosity of CHF increased obviously when CaCO₃ was removed by acid, while the breakage strength decreased slightly. CHF presented a good drying stability. POLYM. COMPOS., 34:1204–1210, 2013. © 2013 Society of Plastics Engineers     

Preparation of high temperature resistant Ag/PI/Cu composite nano particles inserted with PI insulating layer

Polyimide (PI)@copper (Cu) composite nano particles have been successfully synthesized from poly(amic acid) triethylamine salts (PAAS) and Cu(II) ions via a one-step high-temperature induction/imidization route. The formation of PI@Cu nano particles has been investigated by the stoichiometric ratio of PAAS and Cu ion. The resulting products, formed stable shell-core structures, exhibited the uniform core-size and thick shell layer. Additionally, the multi-layer structure, Ag@PI@Cu, was successfully prepared via a post process of PI@Cu nanoparticles. The morphology of the formed “Sunflower-mode” structure, with the pistil of Cu, the sunflower seed of PI, and the petal of Ag, was also characterized by SEM and TEM. Both electrical resistivity and thermal conductivity of nano particles were measured. The coefficient of heat conduction of Ag@PI@Cu is even 255 times, 754 times, 3081 times, and 1310 times as large as PI@Cu in 50 °C, 100 °C, 150 °C, and 200 °C, respectively. The resistance of both nano particles is that the result of Rs_PI@Cu and Rs_Ag@PI@Cu is 11.0*10⁹ Ω and 0.11 Ω, respectively, and also the difference between them is more than 10¹².