聚乙烯醇/改性纳米蒙脱土复合材料的制备与性能

纳米蒙脱土(MMT)用十六烷基三甲基溴化铵进行改性制得有机改性的MMT(OMMT),用其作为聚乙烯醇(PVAL)的改性材料,采用溶液共混、流涎成膜制得PLA/OMMT复合材料,考察了OMMT的用量对PVAL复合材料性能的影响。用傅立叶变换红外光谱(FTIR)仪、差示扫描量热仪、扫描电子显微镜、X射线衍射仪、万能力学试验机等对复合材料性能及结构进行表征和分析。结果表明,FTIR显示十六烷基三甲基溴化铵成功进入MMT结构中,OMMT成功制得;随着OMMT添加量的增加,复合材料热稳定性提高,断裂伸长率降低,拉伸强度呈现先增加后降低趋势,当其含量为9%时达到最大;SEM显示OMMT含量9%时,OMMT与PVAL相容性最好,表面光滑,含量再增加,出现团聚现象,力学性能受到影响。     

用原位有机改性法制备的溴化丁基橡胶／蒙脱土复合材料的性能

采用原位有机改性法制备了溴化丁基橡胶(BIIR)/蒙脱土(MMT)复合材料,并对其硫化特性和力学性能进行了研究,用X射线衍射仪时复合材料中MMT的层间距进行了表征,并与钠基蒙脱土(Na-MMT)、有机蒙脱土(OMMT)和BIIR形成的复合材料进行了对比.结果表明,用原位有机改性法制备的BIIR/MMT复合材料的硫化特性和力学性能优于BIIR/Na/MMT复合材料,甚至优于BIIR/OMMT复合材料;采用原位有机改性法,可使BIIR/MMT体系中MMT的插层效果明显改善.     

有机蒙脱土对低蛋白天然橡胶的补强作用研究

对片层结构的蒙脱土(MMT)进行表面改性,由改性的有机蒙脱土(OMMT)对低蛋白天然橡胶(LPNR)进行补强,采用机械混炼法制备LPNR/OMMT复合材料,研究OMMT对LPNR/OMMT复合材料性能的影响。结果表明:MMT适合采用双十八烷基二甲基氯化铵改性;随着OMMT用量增大,LPNR/OMMT复合材料的交联网络结构、物理性能、抗压缩永久变形性能和耐老化性能明显改善;当OMMT用量为8份时,复合材料的综合性能最佳。OMMT对LPNR的补强研究可以为改善LPNR的性能提供参考,有助于扩大LPNR的应用领域。     

新型有机蒙脱土的制备及其在聚丙烯改性中的应用

采用十六烷基三甲基溴化铵（CTAB） 、环氧树脂（EP）、异佛尔酮二异氰酸酯(IPDI)、十八胺(ODA)对钠基蒙脱土(MMT)进行干法插层改性, 分别制备了CMMT、EMMT、IMMT和OMMT等新型有机蒙脱土,并对聚丙烯(PP)进行熔融改性制得PP/OMMT纳米复合材料。通过傅里叶变换红外光谱仪、X射线衍射仪 、透射电子显微镜、差示扫描量热仪等分析手段对新型有机蒙脱土及纳米复合材料的结构形态及性能进行了研究。结果表明,OMMT层间距由蒙脱土的1.5626 nm扩大到4.2828 nm, OMMT片层均匀分散在PP基体中;当OMMT含量为5 %（质量分数,下同）时,纳米复合材料拉伸强度、断裂伸长率及冲击强度分别比纯PP提高了25.9 %、17.1 %和127.1 %;同时,加入OMMT后,PP的结晶度先升高后降低。     

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。     

胶合板用脲醛树脂胶粘剂的纳米改性

以MMT(蒙脱土)或OMMT(有机蒙脱土)作为改性剂,两者分别在UF(脲醛树脂)合成的不同阶段(加成阶段、缩聚阶段和缩聚后期)中以同一投料比引入体系中,制备相应的改性UF胶粘剂。研究结果表明:当n(F):n(U)=1.2:1、w(MMT或OMMT)=2%(相对于尿素总质量而言)时,MMT和OMMT的引入,能使相应改性UF胶粘剂的某些性能(如黏度、固含量、胶接强度和固化时间等)增加、游离甲醛含量降低;OMMT的改性效果优于MMT,并且OMMT在加成阶段投入时降醛效果明显,在缩聚阶段投入时补强效果明显。     

一种有机改性MMT及用于高温硫化硅橡胶的交联方法

由天津大学申请的专利(公开号CN101831084A,公开日期2010-09-15)"一种有机改性MMT及用于高温硫化硅橡胶的交联方法",提供了一种有机改性蒙脱土(MMT)及用于高温硫化硅橡胶的交联方法:(1)对MMT进行改性制得有机改性MMT;(2)将1～5份有机改性MMT     

有机蒙脱土对单宁酸的吸附性能

利用十六烷基二甲基羟乙基溴化铵对钠基蒙脱土（MMT）进行离子交换改性,制得有机蒙脱土（OMMT）,并通过FT-IR、XRD对MMT改性前后的结构进行表征。通过静态吸附试验,探究OMMT对单宁酸（TA）的吸附条件和吸附机理。结果表明,OMMT吸附TA对pH值有较大的依赖性,吸附最佳pH值在4.0左右;吸附平衡时间为6h,吸附动力学曲线符合准二级动力学模型;吸附等温线用Langmuir方程比Freundlich方程能更好地描述;在pH值为4.0、TA初始浓度为500 mg/L、温度为20℃时,最大吸附容量为181.6mg/g;热力学参数ΔG、ΔH均为负值表明吸附为自发的放热过程。在饱和吸附和解吸重复7次后,再生OMMT吸附容量下降不到20%。     

对大学高分子化学实验中白乳胶的制备的改进

采用十六烷基三甲基溴化铵对钠基蒙脱土进行有机化改性制得有机蒙脱土(OMMT),红外光谱(FT-IR)分析了OMMT的结构。将无机蒙脱土和有机蒙脱土分别代替制备白乳胶中的乳化剂制得新型白乳胶。与目前普遍选用的以OP-10为乳化剂的乳液聚合相比,改进后的实验反应时间缩短,聚合物颗粒分布均匀,实验成功率高,节约了实验成本,极大地调动了学生做实验的积极性。     

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.     

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...     

HIPS/蒙脱土复合材料炭层结构对阻燃性能的影响

采用熔融插层法制备了不同有机蒙脱土(OMMT)及无机蒙脱土(MMT)含量的HIPS/OMMT和HIPS/MMT复合材料,并通过锥形量热仪评价了复合材料的阻燃性能;采用数码相机、扫描电镜(SEM)观察了燃烧残余物结构。结果表明,OMMT的加入显著提高了HIPS/OMMT复合材料阻燃性,而MMT的加入,HIPS/MMT复合材料的阻燃性能提高不明显。HIPS/OMMT复合材料燃烧结束形成了皮层-蜂窝层复合的炭渣结构,对其阻燃性有重要的影响。     

Polypropylene nanocomposites prepared with natural and ODTABr‐modified montmorillonite

In this study, the main goal is to obtain montmorillonite nanocomposites of polypropylene (PP). To achieve this goal, a two‐phase study was performed. In the first part of the work, organomodified clay (OMMT) was synthesized and characterized. Octadecyltrimethylammonium bromide (ODTABr) cationic surfactant was added to the clay (Na‐activated montmorillonite, MMT) dispersions in different concentrations in the range of 5 × 10^?5–1 × 10^?2 mol/L. Rheologic, electrokinetic, and spectral analyses indicated that ODTABr has interacted with MMT at optimum conditions when the concentration was 1 × 10^?2 mol/L. In the second part, modified (OMMT) and unmodified (MMT) montmorillonite were used to obtain PP nanocomposites (OMMT/PP and MMT/PP, respectively). The nanocomposites were prepared by melt intercalation where the montmorillonite contents were 1 or 5% (w/w) for each case. The thermal analyses showed that the thermal properties of OMMT/PP nanocomposites were better than MMT/PP, and both of them were also better than pure polymer. Increase in the concentration of MMT (or OMMT) decreased the thermal resistance. Based on the IR absorption intensity changes of regularity and conformational bands, it is found that the content of the helical structure of macromolecular chains has increased with increasing concentrations of both MMT and OMMT in the nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

SEBS/蒙脱土复合材料结构及热性能研究

采用十二烷基三苯基溴化膦(DTPB)改性钠基蒙脱土(Na+-MMT),利用熔融插层法制备氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)/蒙脱土复合材料。采用X射线衍射仪、红外光谱仪、场发射扫描电镜、热重分析仪对样品进行结构表征和性能测试,比较不同有机化蒙脱土(OMMT)对SEBS/OMMT复合材料的影响。结果表明:无论是MMT还是OMMT都起到了阻止SEBS热失重进程的发展,且携带苯基的DTPB有机改性剂有利于OMMT与SEBS复合材料的相容性。     

Improvement of mechanical,thermal and antimicrobial properties of organically modified montmorillonite loaded polycaprolactone for food packaging

The aim of this study is to evaluate the biodegradable packaging materials which will be an alternative to traditional synthetic packaging materials. For this purpose, packaging films containing polycaprolactone (PCL), montmorillonite (MMT), and organically modified montmorillonite (OMMT) were prepared by solution casting method, and the mechanical, physical, structural, antimicrobial, and antifungal properties of these films were examined. Cetyl trimethyl ammonium bromide (CTAB) was used for the modification of montmorillonite. The structural properties of the prepared films were characterized by attenuated total reflection-Fourier transform infrared, X-ray powder diffraction, thermogravimetric analysis, and scanning electron microscopy. The PCL/OMMT structure was found to be thermally more stable than the PCL/MMT structure. The addition of OMMT to PCL improved the thermal and mechanical properties of the films compared with the pure PCL and PCL/MMT films. In addition, adding MMT/OMMT to the PCL caused an increase in the hardness of the films. In the antimicrobial analysis, while no inhibition effect was observed in PCL/MMT films, PCL/OMMT films showed inhibition effect against Staphylococcus aureus. Antifungal tests performed with the prepared films showed that the film-wrapped bread did not deteriorate for 40 days. It is thought that PCL/MMT and PCL/OMMT films prepared in this study will provide an advantage in applications as packaging material.     

Structure and Property of PU/MMT Nanocomposites by In-Situ Polymerization

A montmorillonite modified by octadecylammonium salt (OMMT) was prepared. A polyurethane (PU)/montmorillonite nanocomposite was synthesized by in-situ polymerization using the OMMT, poly(propylene glycol), 4,4-diphenylmethylate diisocyanate, and 1,4-butanediol. The MMT platelets were dispersed in PU matrix on a 10 ～ 50 nm scale. Compared to that of pure PU, the tensile strength and tear strength of the PU/OMMT nanocomposites increased, respectively, and the MMT platelets dispersed on a nanometer scale enhanced the PU. The temperature of initial weight loss of the PU/OMMT nanocomposites was lower than that of pure PU because of the acid catalytic action of protonated MMT platelets in the first thermodegradation step. But its temperature of initial weight loss was higher than that of pure PU because of the barrier effect of the MMT platelets in the second thermodegradation step.     

Processing thermal stability and degradation kinetics of poly(vinyl chloride)/montmorillonite composites

Thermal stability of polyvinyl chloride (PVC) based montmorillonite composites with either sodium montmorillonite (MMT) or alkyl ammonium ion modified montmorillonite (OMMT) were investigated by thermogravimetric analysis. The apparent activation energies associated with the first thermal degradation stage were calculated by the methods of Flynn–Wall–Ozawa and Kissinger in nitrogen atmosphere at several different heating rates. The processing thermal stability of PVC and PVC/MMT(OMMT) composites was also discussed. Increase of mixing torque did not result in a larger intercalation extent of PVC on MMT; instead, it unexpectedly induced discoloration of PVC and then deteriorated the processing stability, especially in the presence of OMMT. The apparent activation energies in the first thermal degradation stage exhibited little difference among PVC, PVC/MMT, and PVC/OMMT composites, and the kinetic compensation effect of S_p^* kept a constant value, indicating that the thermal stability and thermal degradation mechanism of PVC were not affected by the presence of either MMT or OMMT, although the processing discoloration of PVC is observed for PVC/OMMT composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1521–1526, 2004     

季铵盐插层剂对高密度聚乙烯性能的影响

采用季铵盐阳离子作为插层剂与钠基蒙脱土层间的无机阳离子进行离子交换,制备系列有机化蒙脱土,利用红外光谱对蒙脱土的结构进行表征,结果表明,插层剂已进入蒙脱土的层间.同时将有机化蒙脱土与HDPE进行熔融插层,制备了纳米聚乙烯复合材料,研究了插层剂对其部分力学性能的影响.     

阴离子开环聚合制备尼龙6/蒙脱土复合材料及其性能研究

以十六烷基三甲基溴化铵为有机插层剂对无机蒙脱土进行处理制得有机蒙脱土（OMMT），然后采用阴离子开环聚合，制备了尼龙6／蒙脱土复合材料。用FT-IR、TG和XRD对有机蒙脱土的插层情况进行了表征。结果表明，插层剂已插入蒙脱土片层中；当OMMT用量为2％时，复合材料的熔点最高，结晶度最大，力学性能最好。