有机蒙脱石的制备新方法及性能表征

四甲基氯化铵(TMA)、十六烷基三甲基溴化铵(CTAB)、双氯乙酸丙二醇酯基双十二烷基四甲基氯化二铵(双子季铵盐GQAS)作为钠基蒙脱石(Na-MMT)的改性剂,分别采用一次插层法和两次插层法对Na-MMT进行有机化改性.X射线衍射(XRD)测试表明,Na-MMT的层间距(d001)值随着改性剂碳链长度的增长而增大,采用一次插层法时,d001值依次由Na-MMT的1.30nm增大至1.34nm、2.89nm和3.72nm,而采用两次插层法时(第一次用TMA,第二次用双子季铵盐插层)OMMT的d001值增大至3.99nm.热重分析(TGA)表明Na-MMT的失重率为13.4%,双子季铵盐一次插层的有机MMT(OMMT)的失重率为40.5%,而用TMA第一次插层,双子季铵盐第二次插层的OMMT的失重率为49.8%.傅里叶变换红外光谱(FT-IR)同样证实采用两次插层法,MMT层间吸附的阳离子与有机阳离子的交换更彻底.用双子季铵盐作为改性剂、通过两次插层法制备OMMT,鲜见文献报道.     

蒙脱土改性酚醛树脂复合材料的制备与性能研究

为提高酚醛树脂(PF)的热稳定性,利用原位插层法制备了PF/蒙脱土(MMT)、PF/有机化蒙脱土(OMMT)纳米复合材料,并比较了PF、PF/OMMT或PF/MMT经高温热处理后的力学性能和导电性能.研究表明,与PF复合后,OMMT和MMT都形成了剥离型的片层结构.与PF/OMMT复合材料相比,PF/MMT的质量保持率...     

不同结构聚苯乙烯/蒙脱土复合材料的熔体流动行为研究

分别将聚苯乙烯树脂(PS)与钠基蒙脱土(Na-MMT)和有机化蒙脱土(OMMT)通过熔融复合制备纳米黏土改性的复合材料。通过X射线衍射(XRD)对复合材料的微观结构进行了分析,采用HAAKE流变仪和熔体流动速率仪研究了复合材料的熔体流动行为。结果表明,Na-MMT在与PS熔融复合前后,其片层间距没有发生变化,PS分子链没有插入蒙脱土片层之间,所形成的是一种填充型复合材料。OMMT在熔融复合后,片层间距显著增大,与PS分子链形成了插层复合结构。蒙脱土含量相同时,PS/Na-MMT复合体系的熔体流动性能比PS/OMMT体系更好。研究认为,熔融复合过程中PS分子链的断链和2种复合材料结构上的差异是影响2种材料流动性能的主要因素。     

改性剂及高密度聚乙烯插层和剥离蒙脱石的分子动力学模拟

为研究高密度聚乙烯/有机改性蒙脱石(PE-HD/OMMT)复合材料中改性剂及PE-HD对蒙脱石(MMT)插层和剥离的影响,采用分子动力学方法模拟了OMMT中不同负载量的十八烷基三甲基氯化铵阳离子(OTAC+)在MMT中的排列方式以及对MMT插层的影响.此外,搭建了PE-HD/OMMT复合材料模型,编写MS Perl脚本...     

PDM-AM/纳米插层复合蒙脱石和PDM-AM-GL/纳米插层复合蒙脱石性能的对比

以单体转化率、聚合物的特性黏度和复合材料旋转黏度为指标,对聚二烯丙基二甲基氯化铵-丙烯酰胺(polymer diallyldimethylammonium chloride-acryhmide,PDM-AM)/纳米插层复合蒙脱石(montmorillonite,MMT)和聚二烯丙基二甲基氯化铵-丙烯酰胺-乙二醛(glyoxal,GL)(PDM-AM-OL)/纳米插层复合MMT分别进行了研究,并对其进行了Fourier红外光谱(Fourier transform infrared spectrometer,FTIR)分析和X射线衍射(x-raydiffraction,XRD)检测.将PDM-AM/纳米插层复合MMT和PDM-AM-GL/纳米插层复合MMT分别应用于皮革预鞣,再用质量分数为2%的标准铬粉鞣制.FTIR结果表明:单体在蒙脱石的存在下成功聚合,通过离心处理能够将聚合物与蒙脱石成功分离.XRD结果表明:PDM-AM/纳米插层复合MMT和PDM-AM-GL,纳米插层复合MMT中蒙脱石的层间距的变化规律相一致.PDM-AM/纳米插层复合MMT与GL的反应使得蒙脱石的层间距有所增加.应用结果表明:采用PDM-AM/纳米插层复合MMT预鞣不利于2%铬粉鞣制;然而当引入醛基之后,采用PDM-AM-GL/纳米插层复合MMT预鞣后,坯革的耐湿热稳定性、填充性均优于单独采用2%铬粉鞣制的坯革.     

尼龙12/OMMT纳米复合粉末的制备及性能

利用十八烷基三甲基溴化铵(OTAB)对蒙脱土(MMT)进行有机改性,并通过溶液插层法制备尼龙12/有机蒙脱土(PA12/OMMT)纳米复合粉末。利用X射线衍射、傅立叶变换红外光谱、扫描电子显微镜等手段对改性后的MMT及PA12/OMMT纳米复合粉末的结构和微观形貌进行表征,并将复合粉末热压成型制成标准件,测试其力学性能和热性能。结果表明,经过有机改性,MMT的层间距由1.24 nm增加到了2.13 nm,且改性后的MMT能均匀地分散在PA12基体中,PA12/OMMT纳米复合粉末的成型件在拉伸强度、弯曲强度、冲击强度和热性能方面都优于纯PA12粉末。PA12/OMMT纳米复合粉末为选择性激光烧结技术(SLS)提供了一种性能良好的粉末材料。     

聚丙烯/尼龙6/纳米蒙脱石复合材料的制备及热性能研究

采用熔融插层法成功制备了聚丙烯(PP)/尼龙6(PA6)/有机化蒙脱石(OMMT)纳米复合材料.用X射线衍射分析(XRD)和透射电镜(TEM)观察了OMMT层间距的变化和材料的结构;用示差扫描量热法(DSC)和热重分析(TG)研究了热性能,并考察了纳米复合材料的拉伸强度.研究结果表明,OMMT的层间距由2.200 nm扩大到2.800 nm,PP/PA6合金高分子链取代了有机化蒙脱石层间的十六烷基三甲基溴化铵而进入到蒙脱石的片层间,加入质量分数为4%的OMMT的复合材料不仅使材料的拉伸强度提高了约15%,还提高了材料的热稳定性,使剩炭率增加了8.1%.     

有机蒙脱石改性PA6/ABS合金材料的制备和性能

利用环氧化合物(EP)表面处理蒙脱石(MMT),制备的有机蒙脱石(OMMT)层片间距增加到5.13 nm,热降解温度高达380.3℃。研究了苯乙烯与马来酸酐(MAH)的共聚物(SMA)对PA6/ABS合金的增容效果,当增容剂用量为4%,合金的综合性能最好。制备了PA6/ABS/OMMT复合材料,随着SMA含量的增加,PA6/ABS/OMMT复合材料力学性能和耐热温度都有较大幅度的提高。     

THPC改性蒙脱石的制备与表征

以四羟甲基氯化磷(THPC)为插层剂,对钠基蒙脱石(MMT)进行有机化改性.探索不同pH值条件下THPC对蒙脱石插层性能的影响.采用红外光谱(FTIR)、X-射线衍射(XRD)、热失重分析(TGA)、扫描电镜(SEM)和能谱分析(EDX)对改性后蒙脱石的形貌、结构及性能进行表征.结果表明,强酸条件更有利于THPC稳定存在与插层,插层后的蒙脱石(OMMT)的层间距及热稳定性得到提高.     

阻隔性尼龙611／有机蒙脱土纳米复合材料的研究

以11-氨基十一酸对蒙脱土(MMT)进行有机化改性,采用原位聚合法制备了尼龙611/有机蒙脱土(OM-MT)纳米复合材料.通过傅立叶变换红外光谱仪研究了OMMT及尼龙611/OMMT纳米复合材料的化学结构,使用扫描电子显微镜观察了纳米复合材料的形貌.详细考察了OMMT含量对尼龙611/OMMT纳米复合材料阻隔性能和力学性能的影响,探讨了OMMT的阻隔机理.结果表明,MMT经有机化改性后,其片层在尼龙基体中分散均匀,并与尼龙基体发生键合作用,使尼龙611分子的内聚力增强,分子链堆积程度提高,极大地提高了阻隔性能;OMMT质量分数为3%时,材料的拉伸强度达到最大值,但在常温、低温下冲击强度略有下降.     

聚乙烯醇/蒙脱石纳米复合材料的结构与性能

通过溶液插层 流延成膜法,以聚乙烯醇和钠质蒙脱石为原料,制备出了不同蒙脱石含量的聚乙烯醇/蒙脱石纳米复合材料薄膜。用X射线衍射(XRD)、扫描电子显微镜(SEM)、热重分析(TGA)和力学性能测试对复合材料的结构和性能进行了表征。结果表明,聚乙烯醇分子成功进入蒙脱石的层间,实现了在纳米尺度上的复合;蒙脱石含量高于7 5wt%形成插层型的纳米复合材料,低于7 5wt%形成剥离型的纳米复合材料;在SEM图片上还观察到了纳米复合材料的微观结构。纳米复合材料的热稳定性、拉伸强度和直角撕裂强度均比纯聚乙烯醇有很大提高。     

A straightforward preparation and characterization of novel poly(vinyl alcohol)/organoclay/silver tricomponent nanocomposite films

In the present investigation, novel poly(vinyl alcohol)/organoclay/silver (PVA/OMMT/Ag) tricomponent nanocomposite (NC) films with different compositions were prepared by solution intercalation method under ultrasonic irradiation process. The NC films were obtained by mixing a colloidal solution consisting of Ag nanoparticles (NPs) (3, 5, 7 and 9 wt%) with a water solution of PVA and OMMT (10 wt%) via solution casting method. The scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA) were utilized to characterize the morphology and properties of the PVA/OMMT/Ag NC films. TGA confirmed that the heat stability of the nanocomposite was improved. The enhancement in the thermal properties of the hybrid materials was due to strong hydrogen bonding between OH groups of PVA, free acid functionalized groups of OMMT, and the Ag NPs. SEM and TEM results also showed that the OMMT and Ag NPs were dispersed homogeneously in the PVA matrix on nanoscale.     

聚乙烯醇/凹凸棒黏土纳米复合膜的制备及其性能

以聚乙烯醇(PVA)和提纯凹凸棒黏土(APT)为原料,采用溶液流延成膜法,制备了系列不同APT含量的PVA/APT纳米复合膜。采用XRD、FTIR和SEM对复合膜的结构进行了表征,测试了复合膜的热性能、力学性能和耐水性能。结果表明,APT可均匀分散在PVA基体中,APT的加入使得PVA的结晶度有所下降但并未改变其晶型。APT与PVA通过氢键作用,改善了复合膜的热稳定性、力学性能和耐水性。当APT含量为4%时,纳米复合膜有最优的性能。     

冷冻处理凹凸棒黏土对PVA/APT纳米复合膜性能的影响

以聚乙烯醇(PVA)和经过不同时间冷冻处理的凹凸棒黏土(APT)为原料,采用溶液-流延成膜法,制备了PVA/APT纳米复合膜,通过红外光谱、XRD和SEM对纳米复合膜的结构和形貌进行了表征,并对复合膜的力学性能及耐水性能进行了测试.结果表明,与未冷冻处理APT相比,经冷冻处理后APT的棒晶可以更好的分散在PVA基体中,纳米复合膜的力学性能和耐水性有明显提高.其中,以冷冻处理16 h APT制备的纳米复合膜性能最优,其拉伸强度、断裂延伸率和耐水性分别提高了17.4％、25.4％和19.2％.     

Effects of co‐plasticization of acetyl tributyl citrate and glycerol on the properties of starch/PVA films

Starch/polyvinyl alcohol (PVA) nanocomposite films by film blowing process were successfully obtained. Starch (1700 g), PVA (300 g), and organically modified montmorillonite (OMMT, 200 g) were blended and plasticized with acetyl tributyl citrate (ATBC) and glycerol (GLY) at weight ratios of 0/100, 5/95, 10/90, 15/85, 20/80, and 25/75. The structural, morphology, barrier, mechanical, and thermal properties of the films, as well as molecular interactions in the nanocomposites were analyzed. The 3.98 nm d‐spacing was the highest in starch/PVA nanocomposite films plasticized with ATBC/GLY ratio of 10/90. The film with ATBC/GLY (5/95) had the lowest WVP (3.01 × 10^?10 g m^?1 s^?1 Pa^?1). The longitudinal tensile strength (TS) of starch/PVA nanocomposite films gradually increased from 4.46 to 6.81 MPa with the increase of ATBC/GLY ratios. The T_g steadily increased from 49.2°C to 55.2°C and the ΔH of the nanocomposite films decreased from 81.77 to 51.43 J/g at the presence of ATBC. The addition of ATBC into GLY plasticized starch/PVA/OMMT system enhanced the intermolecular interaction in the nanocomposites. This study proved that ATBC was an excellent compatibilizer in the preparation of starch/PVA/OMMT nanocomposite films. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42544.     

一种含氮磷蒙脱土阻燃剂的合成及表征

采用二氯化磷酸苯酯,2-溴乙胺氢溴酸盐,十二烷基二甲基叔胺等为原料合成含有氮磷元素的双长链烷烃季铵盐,并用其对蒙脱土进行有机化插层改性,并通过红外光谱（FT-IR）、X射线衍射（XRD）、热重分析（TGA）以及沉降实验等表征手段对含氮磷蒙脱土阻燃剂进行研究,最后将改性后的有机蒙脱土（OMMT）与聚碳酸亚丙酯（PPC）复合,研究其热性能与应用前景.     

Preparation and properties of poly(vinyl alcohol)-clay nanocomposite materials

A series of polymer-clay nanocomposite (PCN) materials that consist of poly(vinyl alcohol) (PVA) and layered montmorillonite (MMT) clay are prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic PVA matrix via an in situ free radical polymerization with AIBN as initiator. Organic vinyl acetate monomers are first intercalated into the interlayer regions of organophilic clay hosts and followed by a one-step free radical polymerization. The prepared poly(vinyl acetate)-clay (PVAc-clay) solution are then saponified via direct-hydrolysis with NaOH solution to form PVA-clay nanocomposite materials. The as-synthesized PCN materials are typically characterized by Fourier-Transformation infrared (FTIR) spectroscopy, wide-angle X-ray diffraction and transmission electron microscopy.The molecular weights of poly(vinyl alcohol) (PVA) extracted from polymer-clay nanocomposite (PCN) materials and bulk PVA are determined by gel permeation chromatography (GPC) analysis with THF as eluant. The viscosity property of PCN materials with different feeding amount of MMT clay is studied by an ubbelohode capillary viscometer. The morphological image of as-synthesized materials is studied by scanning electron microscopy (SEM) and optical polarizing microscope (OPM). Effects of the material composition on the thermal stability, mechanical strength, optical clarity of PVA along with a series of PCN materials, in the form of fine powder and free-standing film, are also studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analyzer (DMA) and UV-visible transmission spectra, respectively.     

Preparation and properties of polyisobutene/organic montmorillonite hot melt pressure-sensitive adhesive (HMPSA)

To enhance the interfacial adhesion between Na-montmorillonite (Na-MMT) and polyisobutene (PIB) matrix, it is necessary to modify Na-MMT in organic way. Organic montmorillonite (OMMT) was successfully modified by Na-MMT with cetyltrimethyl ammonium bromide (CTAB) intercalation reagent. The X-ray diffraction (XRD) result showed that the d-spacing of Na-MMT was increased from 1.424 to 2.480 nm after organic modification. PIB/OMMT hot melt pressure-sensitive adhesive (HMPSA) samples were prepared by melt-intercalation process. The amount of OMMT was optimized according to the system stability and adhesion performance. The effects of OMMT content on rheological, adhesion and thermal properties of PIB HMPSA were investigated. Adhesion performance and system stability of PIB HMPSA were greatly improved by adding moderate amounts of OMMT. In addition, the sample containing 1 wt% OMMT exhibited optimal adhesion property and excellent stability, meanwhile, its 180° peel strength was 1.19 times greater than pristine sample.     

Fabrication and characterization of electrospun fibrous nanocomposite scaffolds based on poly(lactide‐co‐glycolide)/poly(vinyl alcohol) blends

Tissue engineering involves the fabrication of three‐dimensional scaffolds to support cellular in‐growth and proliferation. Ideally, the scaffolds should be similar to the native extracellular matrix (ECM). Electrospun polymer nanofibrous scaffolds are appropriate candidates for ECM mimetic materials since they mimic the nanoscale properties of ECM. Electrospun polymer nanocomposites based on poly(lactide‐co‐glycolide) (PLGA)/poly(vinyl alcohol) (PVA) and organically modified montmorillonite (OMMT) were prepared by a solution intercalation technique followed by electrospinning. The morphology of fibrous scaffolds based on these nanocomposites was investigated using scanning electron microscopy. The scaffolds showed highly porous structure within the nanofibres of diameters ranging from 400 to 700 nm. X‐ray diffractometry gave evidence of good dispersion of the OMMT in the blends with exfoliated morphology. Measurements of the water uptake and water contact angle of the fibrous scaffolds indicated significant improvement in the hydrophilicity of the scaffolds. Evaluations of the mechanical properties and unrestricted somatic stem cell culture of the electrospun fibrous nanocomposite scaffolds revealed that the PLGA90/PVA10/1.5% OMMT and PLGA90/PVA10/3% OMMT samples are the most useful from the tissue engineering application viewpoint. Copyright © 2010 Society of Chemical Industry     

常压等离子体射流对聚乙烯醇薄膜性能的影响

用常压等离子体射流处理不同含水率聚乙烯醇（PVA）薄膜,通过扫描电镜（SEM）观察薄膜表面形态,并用红外光谱测试仪（FTIR）、X光电子能谱（XPS）、X射线衍射仪（XRD）分析了等离子体处理前后含水率为1.85%MC及41.33%MC两种 PVA化学结构及结晶结构的变化。试验结果表明:水分可加速氦气/氧气等离子体对PVA刻蚀及氧化,其中刻蚀速率达0.68μm/min,氧含量从30.8%提高到34.8％;同时,经过处理的薄膜结晶度增加了48％。