无机粘土的烷基铵盐改性及NBRCNs的结构与性能研究

采用长链脂肪族季铵盐改性有机粘土的方法,研究了烷基铵盐改性剂的碳链长度及配比对无机粘土(MMT)改性效果的影响。结果表明,同一改性剂配比下,由不同碳链长度的烷基铵盐改性剂改性MMT制备的丁腈橡胶/粘土纳米复合材料(NBRCNs)的微观结构、力学性能和分散相态不同,碳链长度适中的十二烷基三甲基溴化铵(CTAB)改性效果较好,碳链长度较长或较短都不利于MMT的改性。对于碳链长度较短的二十二烷基三甲基溴化铵(DTAB),当DTAB用量增加,粘土片层间距增大,力学性能提高。对于碳链长度较长的十八烷基三甲基溴化铵(STAB),STAB用量降低有助于扩大粘土片层间距和提高力学性能。     

阴/阳离子表面活性剂复配改性粘土/橡胶纳米复合材料的结构与性能

采用阴离子表面改性剂十二烷基磺酸钠(SDS)与阳离子表面改性剂十八烷基三甲基溴化铵(STAB)复配改性粘土,制备有机粘土/橡胶纳米复合材料,考察其结构和性能。结果表明:当SDS/STAB质量比为2/4时,有机粘土/丁腈橡胶(NBR)纳米复合材料的综合物理性能最优,STAB的有机阳离子取代无机粘土层间可交换的阳离子,SDS通过碳-氢键与无机粘土层间非极性较强的质点发生范德华力及离子静电吸附作用,获得晶层间距更大的有机粘土;与非极性的丁苯橡胶和天然橡胶相比,极性的NBR使粘土的远程聚集趋势减小和界面吸附作用增强,相应复合材料的物理性能增幅更大。     

有机插层剂对聚酰胺6／MMT纳米复合材料制备的影响研究

以烷基胺、季铵盐和氨基酸作为有机插层剂与蒙脱土片层进行阳离子交换，制备出层间距不同的有机蒙脱土。采用熔融插层法和原位聚合法分别制备聚酰胺（R％）／蒙脱土（MMT）纳米复合材料，并利用XRD、FT-IR、TEM对有机蒙脱土及纳米复合材料进行结构表征。研究结果表明：用烷基胺、季铵盐和氨基酸有机插层剂改性的蒙脱土层间距由原来的1．25nm分别增大到3．21nm、3．99nm和1．82m；季铵盐有机插层剂更适用于熔融插层法制备PA6／MMT纳米复合材料，而氨基酸有机插层剂更适用于原位聚合法制备PA6／MMT纳米复合材料。     

复配改性黏土/丁腈橡胶纳米复合材料的结构及性能

用不同阴离子表面活性剂十二烷基磺酸钠(SDS)和十二烷基苯磺酸钠(SDBS)与阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)复配改性无机黏土,制备了有机改性黏土/丁腈橡胶(NBR)纳米复合材料,并表征了有机黏土与纳米复合材料,考察了不同表面活性剂及配比对纳米复合材料物理机械性能的影响。结果表明,CTAB/SDS复配改性黏土/NBR纳米复合材料的层间距比CTAB改性黏土/NBR纳米复合材料增加了1.15 nm,具有更多的插层结构,橡胶基体中黏土颗粒分布细致、均匀,且黏土片层间无聚集体存在;CTAB/SDS复配改性黏土/NBR纳米复合材料的物理机械性能优于CTAB/SDBS复配改性黏土/NBR纳米复合材料及CTAB改性黏土/NBR纳米复合材料,且当CTAB/SDS(质量比)为4∶2时,纳米复合材料的拉伸强度、撕裂强度及扯断伸长率出现最大值,其中,拉伸强度和撕裂强度较CTAB改性黏土/NBR纳米复合材料分别提高了62.7%和12.3%。     

丁腈橡胶/粘土纳米复合材料的阻燃性研究

通过利用自制有机改性粘土，采用插层复合法成功制备了丁腈橡胶（NBR）／粘土纳米复合材料。透射电子显微镜（TEM）结果证实了粘土片层在橡胶基体中的纳米级分散。研究结果表明：纳米复合材料的阻燃性能明显高于炭黑补强胶料的阻燃性能。     

十六烷基氯化吡啶改性无机黏土/丁腈橡胶纳米复合材料的结构与性能

采用十六烷基氯化吡啶(CPC)改性无机黏土(蒙脱土,MMT)并制备橡胶/黏土纳米复合材料,研究了有机黏土/丁腈橡胶纳米复合材料(NBRCNs)的结构、力学性能和微观相态。结果表明,CPC改性MMT所制备NBRCNs中有机黏土的片层间距5.10 nm要大于十六烷基三甲基溴化铵(CTAB)改性MMT的4.41 nm,表明其形成了更多的插层结构。当MMT与改性剂的质量比为2.5/1.0时,CPC改性MMT所制备NBRCNs的拉伸强度和撕裂强度分别为4.72 MPa和26.66 kN/m,较CTAB改性MMT的3.28 MPa和16.50 kN/m分别提高了44%和62%,且前者所制备NBRCNs的相态分散程度比后者更加细致均匀。将CPC改性MMT用于添加丁腈橡胶等极性橡胶的增强效果要优于添加丁苯橡胶等非极性橡胶。     

有机改性的粘土与丁苯橡胶纳米复合材料的制备方法

由北京化工大学申请的专利（专利号CN1900149,公开日期2007-01-24）“有机改性的粘土与丁苯橡胶纳米复合材料的制备方法”,涉及的有机改性粘土／SBR纳米复合材料的制备方法是：先将有机改性剂（烷基铵盐）水溶液与粘土水悬浮液混合[有机改性剂与粘土的质量比为（10-50）：100],然后与丁苯胶乳混合,再经过破乳絮凝、干燥脱水、混炼、硫化得到产品。     

偶联剂对PVC/粘土的插层效果及性能研究

采用固相法，对粘土进行有机插层改性；并与聚氯乙烯（PVC）熔融插层制备了纳米复合材料。结果表明，偶联剂KH560处理的有机粘土（用Org-560表示）与PVC形成PVC／org-550插层型纳米复合材料，而偶联剂KH550处理的有机粘土（用Org-550表示）与PVC形成的PVC／Org-550则是剥离型纳米复合材料；PVC／有机粘土纳米复合材料的玻璃化转变温度高于PVC；Org-550对PVC的力学性能优于Org-560的。     

CTAB/CPL复配改性黏土制备NBRCNs的结构与性能研究

采用CTAB/CPL(比例为3.0g∶1.0g)复配改性有机黏土制备NBRCNs,考察了复配改性有机黏土制备的NBRCNs的微观结构、力学性能和分散相态。实验结果表明,无机黏土经CTAB/CPL复配改性后,黏土晶层间距由起始1.25nm扩大至1.82nm,NBRCNs中黏土晶层间距进一步扩大为4.67nm,即橡胶大分子链进一步插层进入黏土片层中,制备得到插层型纳米复合材料。有机黏土用量为10份时,复配改性有机黏土制备的NBRCNs的各项力学性能最优,拉伸强度为5.16 MPa,撕裂强度为20.97kN/m,较纯NBR硫化胶的1.53MPa和8.77kN/m分别提高了237%和139%,且明显优于采用单一阳离子CTAB改性有机黏土制备的NBRCNs,充分显示了复配有机改性黏土的可行性和优越性。复配有机改性黏土制备的NBRCNs的微观分散相态优于单一阳离子改性有机黏土制备的NBRCNs。     

PB-TPE/OMMT复合材料的结构与性能研究

采用烷基季铵盐类有机插层剂十六烷基三甲基溴化铵（CTAB）对蒙脱土（MMT）进行了改性处理,制备了有机化蒙脱土（OMMT）,并对聚丁烯-1热塑性弹性体（PB-TPE）进行了马来酸酐接枝改性（PB-TPE-g-MAH）。以PB-TPE-g-MAH为相容剂,通过熔融插层法制备了PB-TPE-g-MAH/OM-MT纳米复合材料。采用傅立叶变换红外光谱（FTIR）、X-衍射（XRD）、透射电镜（TEM）等手段分析了材料结构。结果表明：OMMT在PB-TPE-g-MAH体系中得到了插层和部分剥离,使有机蒙脱土片层间距由原来的1.96 nm增加到3.81 nm。与不含蒙脱土的PB-TPE相比,PB-TPE-g-MAH/OMMT纳米复合材料的拉伸性能得到明显提高。     

Studies on properties of softwood (Ficus hispida)/PMMA nanocomposites reinforced with polymerizable surfactant-modified nanoclay

Soft wood (Ficus hispida) was chemically modified by impregnation of methyl methacrylate monomer, glycidyl methacrylate (GMA), a cross-linking agent, and montmorillonite (MMT) using catalyst heat treatment. MMT was modified by using a polymerizable surfactant 2-acryloloxy ethyl trimethyl ammonium chloride (ATAC) and a mixture of surfactants ATAC and cetyl trimethyl ammonium bromide (CTAB) in a molar ratio of (1:1). A comparative study on different properties of the prepared wood polymer nanocomposite (WPNC) based on impregnation of intercalating mixture containing MMA/GMA/clay modified by both the surfactants (ATAC and CTAB) and MMA/GMA/clay modified by only surfactant ATAC were done. FTIR, XRD, and TGA studies were employed for the characterization of clay and WPNC. WPNC prepared by using combined surfactant-modified clay along with MMA/GMA exhibited improved dimensional stability, chemical resistance, thermal stability, mechanical properties, and lower water uptake than that of WPNC prepared by using single surfactant-modified clay and MMA/GMA system.     

海泡石的酸处理和有机海泡石的制备

用热酸法对海泡石样品进行提纯和改性,然后用十六烷基三甲基溴化铵(CTAB)对热酸活化的海泡石进行有机化改性,制备有机海泡石.采用X射线衍射分析(XRD)、傅立叶红外光谱分析(TFIR)和扫描电镜显微分析(SEM)等测试手段分别对酸化海泡石和有机海泡石进行分析.结果表明:酸活化能有效除去样品中的方解石等杂质,海泡石中部分的Mg被H取代,同时失去端位上与Mg配位的结构水.提高固液比、延长时间、升高温度可促进海泡石的酸化效果,改变酸浓度对海泡石酸化效果影响不明显.有机化处理后海泡石层间距由12.16 nm增加到12.30nm,且有机化有利于海泡石纤维解束.     

阳离子改性蒙脱土插层脲醛树脂胶粘剂的性能研究

以十六烷基三甲基溴化铵(CTAB)、十二烷基三甲基溴化铵(DTAB)和CTAB/DTAB分别作为蒙脱土(MMT)的改性剂,制成了相应的有机插层剂(如CTAB-MMT、DTAB-MMT和OMMT等);然后采用复合插层法制成了压制胶合板用有机插层剂/脲醛树脂(CTAB-MMT/UF、DTAB-MMT/UF和OMMT/UF)复合胶粘剂。结果表明:OMMT的层间结构最优;当w(OMMT)=3%时,相应的OMMT/UF复合胶粘剂的综合性能最好,由其压制而成的胶合板的粘接强度和游离甲醛释放量均满足相关标准要求。     

Use of different alkylammonium salts in clay surface modification for epoxy‐based nanocomposites

Layered silicates become widely used reinforcement material in the polymer nanocomposite production in recent years due to their high aspect ratio, ease of processing, and low cost. In this present study, the aim was to evaluate the usability of a raw clay source (Resadiye, Turkey) in the production of epoxy/clay nanocomposites and to investigate the effects of different surface modifiers. For this purpose, raw Na–montmorillonite clay was first purified and then surface modified by using different types of alkylammonium salts: tetramethyl ammonium bromide, benzyl triethyl ammonium bromide, dodecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, and octadecyl trimethyl ammonium bromide. Purification and surface modification of this clay were evaluated by using the following analyses; X‐ray diffraction (XRD), cation exchange capacity (CEC), particle size distribution, and dissolved organic content. These analyses simply indicated that surface modification increased both interlayer spacing between the silicate layers and CEC of the clay. These improvements were directly proportional with the chain length of the surface modifier. Nanocomposite specimens were produced by adding 0.5 wt% surface modified clay into the epoxy matrix. These specimens were characterized by XRD, Si‐mapping facility of SEM, and mechanical tests. XRD results indicated an exfoliated structure whereas Si‐mapping showed the uniform distribution of clay particles in epoxy, leading to improved mechanical properties, for instance more than 100% increase in fracture toughness of the neat epoxy specimen. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

插层有机纳米蒙脱土改性骨胶胶粘剂的制备与性能研究

用十六烷基三甲基溴化铵和十二烷基三甲基溴化铵对蒙脱土(MMT)进行有机化处理,得到有机纳米MMT;将骨胶插层到有机纳米MMT中,再经环氧氯丙烷(ECH)交联改性,得到插层有机纳米MMT改性骨胶胶粘剂。通过单因素试验探讨了各种工艺因素对胶粘剂黏度的影响。结果表明:制备插层有机纳米MMT改性骨胶胶粘剂的最佳工艺条件为酸解温度60℃,接枝共聚温度50℃,m(ECH)≈0.5 g,接枝共聚时间90 min,m(MMT)=0.35 g;在此工艺条件下制取的骨胶胶粘剂,其适用期增至60 d,凝固点降至-4℃,克服了传统骨胶储存期短、常温呈固态以及使用时要现用现熬等缺点,具有良好的应用前景。     

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.     

Effects of modified attapulgite on the properties of attapulgite/epoxy nanocomposites

The aim of this work is to figure out the true effects of filler modification in attapulgite (ATP)/epoxy (EP) nanocomposites through comparing the properties of composites containing pristine or modified ATP clay. ATP particles were first pretreated by a silane coupling agent KH550 and cationic surfactant cetyl trimethyl ammonium bromide (CTAB) separately, and then a series of nanocomposites were prepared with varied clay loadings. Fourier transform infrared spectroscopy and thermogravimetric analysis were used to confirm the modification. The wicking experiment showed the compatibility of ATP with EP increased after modification, especially for CTAB‐ATP, which was discovered to exhibit the highest affinitive ratio. Mechanical and thermal properties of the composites were enhanced on the introduction of ATP. Regarding the efficiency of mechanical reinforcement, KH550 was superior to CTAB at lower ATP loadings (<2 wt%), whereas CTAB became relatively more effective at higher loadings. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

Effect of clay content and clay/surfactant on the mechanical, thermal and barrier properties of polystyrene/organoclay nanocomposites

In the present paper, three ammonium salts namely, tetraethylammonium bromide (TEAB), tetrabutylammonium bromide (TBAB), and cetyltrimethylammonium bromide (CTAB) were employed to prepare organoclay by cation exchange process. Polystyrene (PS) /clay nanocomposites were prepared by melt blending using commercial nanoclay and organoclays prepared using above mentioned salts. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis indicated that the modified clays were intercalated and/or exfoliated into the polystyrene matrix to a higher extent than the commercial nanoclay. Further, amongst the modified organoclays, TBAB modified clay showed maximum intercalation of clay layers and also exfoliation to some extent into the polystyrene matrix. TEM micrograph exhibited that TBAB modified clay had the best nanoscale dispersion with clay platelet thickness of ∼6–7 nm only. The mechanical properties of the nanocomposites such as tensile, flexural and izod impact strength were measured and analyzed in relation to their morphology. We observed a significant improvement in the mechanical properties of polystyrene/clay nanocomposites prepared with modified clays as compared to commercial organoclay, which followed the order as; PS/TBAB system > PS/CTAB system > PS/TEAB system. Thermogravimetric analysis (TGA) demonstrated that T₁₀, T₅₀ and Tmax were more in case of polystyrene nanocomposites prepared using modified organoclays than nanoclay [nanolin DK4] and maximum being in the case of PS/CTAB system. The results of Differential Scanning Calorimetry (DSC) confirmed that the glass transition temperature of all the nanocomposites was higher as compared to neat polystyrene. The nanocomposites having 2% of TBAB modified clay showed better oxygen barrier performance as compared to polystyrene.     

Effects of surfactant concentration on alkyl chain arrangements in dry and swollen organic montmorillonite

To investigate the effects of surfactant concentration on alkyl chain arrangements in dry and swollen organic montmorillonite (OMt), Na⁺-montmorillonite (Na⁺-Mt) was modified with cationic surfactants with different alkyl chain lengths, including tetradecyl-trimethylammonium bromide (TTAB), cetyltrimethylammonium bromide (CTAB) and steartrimonium bromide (STAB), at a series of concentrations. The properties of dry and swollen OMt were characterized by thermal analysis and X-ray diffraction. Two kinds of novel arrangement of alkyl chains were found for dry CTAB-Mt. The surfactant polar head showed two arrangements when the CTAB concentration increased from 0.23 to 0.45 cation exchange capacity (CEC). The arrangement of the paraffin-type bilayer had a larger tilting angle at 1.93 CEC than that of reported research, leading to a maximum d-spacing of 5.81 nm. For swollen CTAB-Mt in the solvent, the d-spacing first increased and then remained constant with increase in the amount of added CTAB. The swelling behavior was proposed, including three distinct stages: solvent-controlling stage, surfactant concentration-controlling stage, and alkyl chain length-controlling stage. The alkyl chain arrangements of dry and swollen OMt were further confirmed by TTAB-Mt and STAB-Mt.     

表面活性剂对SAPO-34晶体形貌的调控研究

分别以拟薄水铝石为铝源,磷酸为磷源,硅溶胶为硅源,三乙胺和四乙基氢氧化铵为模板剂,在反应体系中添加十八烷基三甲基溴化铵(STAB)合成板层状小晶粒SAPO-34分子筛。通过XRD、SEM、FT-IR、NH_3-TPD和N_2吸附-脱附等手段对样品进行表征。并且考察了样品在甲醇制烯烃(MTO)反应中的催化性能。结果表明,由于STAB长链分子的存在,在反应中形成了特定的有机序列,可以使分子筛样品的粒径变小,厚度变薄,强酸量略微增加,对比与传统方法做出的分子筛样品,具有更高的催化寿命和双烯(乙烯+丙烯)选择性。