剥离型硅橡胶/黏土纳米复合材料研究

利用层状硅酸盐制备有机 无机纳米复合材料是当前人们研究的热点[1,2 ] ,这类材料具有较常规聚合物 无机填料复合材料无法比拟的优点 ,可以明显改善高分子材料的物理机械性能、热稳定性、气体阻隔性、阻燃性、导电性、光学性等 .一般来说 ,聚合物 层状硅酸盐 (Ｐｏｌｙｍｅｒｌａｙｅｒｅｄｓｉｌｉｃａｔｅ ,ＰＬＳ)纳米复合材料可分为插层型和剥离型两种类型 .插层型纳米复合材料即聚合物插入到硅酸盐层中 ,硅酸盐在近程仍保持原有的有序晶体结构 ,在远程则是无序的 .对弹性体而言 ,硅酸盐含量在插层型杂化材料中的含量比较高 ,力学性能…     

茂钛催化剂苯乙烯原位间规聚合制备sPS/蒙脱土纳米复合材料

聚合物基纳米复合材料具有常规有机 /无机复合材料所没有的结构和形态 ,其性能较普通的聚合物复合材料更优异 ,因而引起人们的广泛关注 [1～ 4 ] .近年来的研究表明 ,运用插层聚合和熔融插层等方法可使某些具有层状结构的硅酸盐与聚合物产生特殊的界面作用 ,并以纳米尺寸均匀分     

聚合物/层状硅酸盐插层纳米复合材料的研究

简述了聚合物 /层状硅酸盐插层纳米复合材料方面的研究进展。阐述了层状硅酸盐的结构与性质以及纳米复合材料形成过程的热力学原理。重点介绍了尼龙、聚丙烯等聚合物的层状硅酸盐插层纳米复合材料的现状和技术发展趋势     

聚丙烯/层状硅酸盐纳米复合材料的制备、结构和性能

聚丙烯／层状硅酸盐纳米复合材料可通过丙烯单体插层聚合、聚丙烯溶液插层和聚丙烯熔融插层等方法制备，得到插层型或剥离型纳米复合材料，形成了与传统填充型聚合物复合材料不同的微观结构，其机械性能，热性能，阻隔性能和流变性能等明显提高，由于聚丙烯的非极性及层状硅酸盐纳米复合材料制备方法的特殊性，该研究具有一定的理论价值。     

原位聚合法制备聚丙烯酸甲酯/ZnAl层状双氢氧化物插层纳米复合材料及其形貌特征

近 2 0年来 ,聚合物 /层状无机物纳米复合材料引起了广泛关注 ,与聚合物材料相比 ,该类纳米复合材料在力学、热稳定性、阻燃、气体阻隔等性能方面都有显著增强 .但所报道的绝大部分无机物均采用蒙脱土为代表的层状硅酸盐[1～ 3] ,而以层状双氢氧化物 (Layered double hydroxide,LDH)为基础制备的聚合物 /层状无机物纳米复合材料的报道极少 .LDH是由水镁石结构中的二价阳离子 (M2 + )被三价阳离子 (M3+ )取代而形成的 ,层上产生的剩余正电荷被吸附在层间的阴离子平衡 .与层状硅酸盐相比 ,L DH层间电荷密度高 ,层与层之间相互作用强 ,导…     

漆酚钛聚合物/蒙脱土纳米复合材料的制备、结构与性能

用溶液插层聚合方法制备漆酚钛聚合物/蒙脱土纳米复合材料(PUTi/OMMT),并用XRD、TEM和TG等对其结构、性能进行测试与表征.XRD结果表明,通过溶液插层,PUTi分子链进入了OMMT片层间,从而使片层间距增大.TEM观察表明OMMT片层在PUTi聚合物中基本达到纳米级分散.与PUTi相比,PUTi/OMMT纳米复合材料具有更好的耐热性能和抗紫外光性能.     

纳米层状双金属氢氧化物改性PU/PMMA的制备及其弛豫行为

采用原位聚合法,制备了聚氨酯(PU)/聚甲基丙烯酸甲酯(PMMA)/层状双金属氢氧化物(LDH)纳米复合体系(PU/PMMA/LDH).通过广角X射线衍射(WXRD)、透射电子显微镜(TEM)对其结构和形貌进行了表征,并通过热失重(TGA)、动态力学分析(DMA)和宽频介电谱(BDRS)研究了LDH含量(φ)对PU/PMMA体系热稳定性和弛豫行为的影响.结果表明,当φ<1 wt%时,LDH在聚合物基体中以剥离结构为主,PU/PMMA/LDH体系的玻璃化温度(Tg)降低,最大损耗因子(tanδmax)增大;而当φ>1 wt%时,LDH在聚合物基体中以插层结构为主,插层结构对聚合物分子链的限制使复合体系的Tg升高、tanδmax降低.LDH表面与PU硬段间的氢键作用,使复合体系的α介电弛豫转变随φ增加而向高温方向移动,弛豫过程激活参数增大.     

一种液晶共聚酯/粘土纳米复合材料的制备及其相转变温度

一些无机微粒被广泛用做聚合物的增强材料,其中特别引起人们注意的是一种粘土,即蒙脱土（ｍｏｎｔｍｏｒｉｌｌｏｎｉｔｅ）．蒙脱土具有层状结构,其特点一是微粒尺寸小,二是可以和多种单体发生插层聚合反应,给出聚合物／蒙脱土纳米复合材料［１～３］．纳米复合材料指的是其基质中分散相的尺寸至少有一维小于１００ｎｍ数量级的复合材料．由于其纳米尺度效应、大的比表面积以及强的界面相互作用,纳米复合材料的物理力学性能优于相同组分常规复合材料．因此,无论从基本理论研究角度还是从应用角度上看,对聚合物纳米复合材料的研究都…     

原位插层聚合法制备聚丙烯酰胺/α-磷酸锆纳米复合材料及其结构表征

聚合物／层状无机物纳米复合材料因具有常规复合材料所没有的结构、形态及较常规聚合物基复合材料更优异的性能而引起人们的广泛关注．α-磷酸锆（α-ZrP）作为一种合成的结构规整的层状无机物，其离子交换容量（600mmol／100g）是粘土的6倍，并具有长径比可控和粒子尺寸分布较窄等特点，是制备聚合物／层状无机物纳米复合材料的优良基体．以往的研究工作主要集中于金属氧化物／α-ZrP层柱材料和聚电解质膜两类复合材料，有关聚合物／α-ZrP插层复合材料的研究报道较少．聚丙烯酰胺（PAM）是一种具有广泛用途的水溶性高分子，作为聚电解质，     

动态扭振法观察环氧树脂/蒙脱土插层聚合物的二次固化

聚合物 /无机纳米复合材料是当今材料研究中的热点。但由于无机纳米颗粒在聚合物中不易分散 ,有时用具有纳米层间距的片晶结构的无机矿物 ,如蒙脱土作填料 ,通过聚合时的热效应来撑开片晶达到蒙脱土的纳米级分散 ,制得所谓的插层聚合物〔1〕。插层型纳米复合材料不仅物理力学性能有很大提高 ,并且也为高分子凝聚态物理工作者提供了研究聚合物分子在二维空间受限情况的理想模型。由于在蒙脱土层间和层外的聚合物所处的环境不一样 ,它们的一些行为会有所不同。本文在用动态扭振法研究环氧树脂 /蒙脱土插层聚合物的等温固化行为时 ,观察到了该…     

PU/MOMMT纳米复合材料的制备与研究

纳米复合材料由于其纳米尺寸效应，表面效应以及纳米粒子与基体界面间强的相互作用，具有优于相同组分常规复合材料的力学、热学等性能，引起了人们的广泛关注。用纳米材料改性聚合物，制备纳米复合材料是获得高性能高分子复合材料的重要方法。1998年以来，Pinnavaia等首先制备了聚氨酯，蒙脱土（PU／MMT）纳米复合材料，研究了有机蒙脱土在聚醚中的分散性。其后Chen等将聚羟基己内酯/蒙脱土（PCL／MMT）纳米复合材料加入到PCL和二苯基甲烷-4，4＇-二异氰酸酯（MDI）合成的预聚体与1，4-丁二醇扩链反应后的溶液中，制备了PU／MMT纳米复合材料。少量PCL／MMT的引入可使复合材料的综合性能大幅提高。     

Study of elastomeric polyurethane nanocomposites prepared from grafted organic–montmorillonite

4,4′-Diphenylmethane diisocyanate (MDI) was grafted on to organic–montmorillonite (OMMT) by reaction between hydroxyl groups (−OH) on surface of the montmorillonite and the isocyanate groups (−NCO) of MDI, thus forming grafted organic–montmorillonite (MOMMT). Intercalated nanocomposites based on polyurethane (PU) and MOMMT were prepared by solution intercalation technology. The interface interaction of PU/MOMMT nanocomposites was better than that of PU/MMT composites. The tensile strength, elongation at break, and tear strength of the PU/MOMMT nanocomposites increased for MOMMT content up to 5% w/w, and then decreased with further increase in MOMMT content. At the same filler content, the tensile strength and tear strength of PU/MOMMT nanocomposites were higher than those of PU/OMMT nanocomposites, whereas the elongations at break of PU/MOMMT nanocomposites were smaller than those of PU/OMMT nanocomposites. The initial temperatures of weight loss of PU/MOMMT nanocomposites were lower than for PU/MMT composites in the first step of thermal degradation, whereas in the second step initial temperatures of weight loss were higher for PU/MOMMT nanocomposites.     

聚碳酸1,2-丙二酯/蒙脱土复合材料的制备与性能

利用阳离子交换法,以十六烷基三甲基溴化铵(HTAB)改性钠基蒙脱土制备了有机改性蒙脱土(OMMT),OMMT的层间距达到了2nm,比普通的钠基蒙脱土增加了0.74nm.采用熔融插层法制备了插层-絮凝型PPC/OMMT复合材料,当复合材料中OMMT含量为5wt%时,复合材料的杨氏模量较纯PPC树脂大幅度提高了61.8%,同时玻璃化温度(Tg)提高了2.4℃,热分解温度提高了32.3℃.因此,OMMT对大幅度提高PPC的杨氏模量具有很大的潜力.     

Structure and properties of rubber/organic montmorillonite nanocomposites prepared by in situ anionic intercalation polymerization

Polybutadiene (PB), polyisoprene (PI), and styrene–butadiene rubber/organic montmorillonite (OMMT) nanocomposites (NCs) were prepared by in situ anionic intercalation polymerization. The intercalation structure, chemical constitution, and morphology of the rubber/OMMT NCs were characterized with X‐ray diffraction, H NMR spectroscopy, and transmission electron microscopy; the thermal and dynamic mechanical properties of the rubber/OMMT NCs were characterized with differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The mechanical properties of PB/OMMT NC were also tested. The results showed that a certain extent of exfoliated rubber/OMMT could be prepared by anionic in situ intercalation polymerization. The incorporation of OMMT obviously changed the microstructure content of PB and PI: the concentrations of the 1,2‐unit, 3,4‐unit, and trans‐1,4‐unit increased dramatically with an increasing concentration of OMMT, and the concentration of the cis‐1,4 structure decreased. The addition of OMMT‐DK1B and OMMT‐DK4 had little effect on the molecular weight and molecular weight distribution, but the addition of OMMT‐DK1 reduced the molecular weight of rubber, and the molecular weight distribution became broad. The glass‐transition temperature, weight‐loss temperature, storage modulus, and loss modulus of the NCs evidently increased, but tan δ decreased. OMMT apparently enhanced the rubber matrix; for example, the breaking strength and hardness of PB/OMMT NC crosslinked rubber increased greatly, but the tear strength and permanent deformation did not change much. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1344–1353, 2005     

Preparation of thermosetting polyurethane nanocomposites by montmorillonite modified with a novel intercalation agent

A novel thermosetting polyurethane (TSPU)/organic montmorillonite (OMMT) nanocomposite has been synthesized. N‐diamino octadecyl trimethyl ammonium chloride (DODTMAC) was used as an intercalation agent to treat Na⁺‐montmorillonite (MMT) and form a novel kind of OMMT. Fourier transform infrared spectroscopy (FT‐IR), wide angle X‐ray diffraction (WAXD), and thermogravimetric analysis (TGA) data indicated that the MMT was successfully intercalated by this intercalation agent, as evidenced by the fact that the basal spacing of MMT galleries was expanded from 1.5 to 3.2 nm. This OMMT was used to prepare the TSPU nanocomposites. Both the reinforcing and compatibilizing performance of the filler were investigated. Tensile tests showed that the tensile strength of TSPU/OMMT‐4 was the highest, and was about 3.62 times higher than that of the pure TSPU, and also the elongation at break showed an enhancement. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) measurements illustrated that the glass transition temperature of the TSPU/OMMT‐4 nanocomposite was improved from 0.5 to 6.5 °C, which corresponded to the restriction of the soft segments of TSPU. The highest initial and center temperatures of TSPU/OMMT‐4 obtained from TGA were due to the highest retard effect of the TSPU molecular chains. WAXD studies showed that the formation of the nanocomposites in all the cases with the almost disappearance of the peaks corresponding to the basal spacing of MMT. SEM and TEM were used to investigate the morphologies of the TSPU/OMMT‐4 nanocomposite, and demonstrated that the nanocomposite was comprised of a well dispersion of a mixture of intercalated and exfoliated silicate layers throughout the matrix. It was proposed that the nano‐reinforcing effect caused by the well‐dispersed silicate layers might reduce the amount and size of voids and increase the length of the crack‐spreading path during tensile drawing. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 519–531, 2007.     

Morphology,rheology property,and crystallization behavior of PLLA/OMMT nanocomposites prepared by an innovative eccentric rotor extruder

An innovative eccentric rotor extruder, which can generate continuous elongation flow, was used to fabricate the poly(L‐lactide) (PLLA)/organo‐modified montmorillonite (OMMT) nanocomposites in different OMMT concentrations. The morphology of the nanocomposites was characterized by thermal gravimetric analyzer, X‐ray diffractometer, and transmission electron microscope. The results showed that the OMMT nanoparticles were uniformly dispersed in the PLLA matrix and mainly existed in intercalation mode. The intercalation and exfoliation process of OMMT in the eccentric rotor extruder may be a double‐side exfoliation, which is more effective than the layer‐by‐layer peeling mechanism based on the shear flow. The influence of OMMT on the rheological behavior of PLLA was investigated by dynamic rheological measurements, showing greater improvement of rheological properties for the nanocomposites. The thermo‐mechanical properties analysis indicated that significant enhancement of E′ can be seen for all the nanocomposites. Presence of intercalated OMMT platelets did not lead to a significant shift of the E″ and tan δ curves compared with that of pure PLLA. The crystallization and melting behavior was studied by differential scanning calorimetry, which indicated that the incorporation of OMMT nanoparticles slightly increased the crystallinity of PLLA matrix. The polarizing microscope was further carried out and showed that the dispersed OMMT nanoparticles acted as a heterogeneous nucleating agent to promote the crystallization of PLLA.     

Properties of poly(vinyl chloride)/wood flour/montmorillonite composites: Effects of coupling agents and layered silicate

Organomodified montmorillonite (OMMT) was prepared using cetylalkyl trimethyl amine bromide. OMMT and wood flour (WF) were surface-modified by silane coupling agent. They were melt-blended with polyvinyl chloride (PVC) and extruded into wood-plastic composite samples using one conical twin screw extruder. The effects of their contents on the composite mechanical properties were investigated. X-ray diffraction, transmission electron microscopy and scanning electron microscopy observed intercalation and dispersion of the OMMT. FTIR and X-ray photoelectron spectroscopy were used to analyze the silane-modification effects. The possible reaction mechanisms were proposed. After wood flour was modified by 1.5 phr silane, the impact strength and the tensile strength of wood flour-PVC composite were increased by 14.8% and 18.5%, respectively. Mechanical tests showed that the addition of OMMT did not enhance the untreated wood flour-PVC composites. However, adding 0.5% OMMT did improve the mechanical properties of the treated ones. The grafting improved the interfacial compatibility between components producing higher properties of the composites. Further addition of OMMT reinforced the composites. Too higher contents of silane and OMMT impaired some properties because of weak interfacial layer and higher concentrated stress. Cone calorimetry showed that the fire flame retardancy and smoke suppression of composites were strongly improved with the addition of OMMT.     

Preparation and properties of PU/MCMMT nanocomposites

The cetyltrimethyl ammonium bromide (CTAB) was used as a swelling agent to be intercalated into the galleries of the montmorillonite (MMT) platelets to get the organic MMT (CMMT). Then 4,4′‐diphenylmethane diisocyanate (MDI) were grafted on CMMT by the reaction between hydroxyls in organic MMT platelets and MDI to synthesize the MDI modified CMMT (MCMMT). Polyurethane (PU)/MCMMT composites were prepared by situ polymerization. The MCMMT platelets dispersed in a PU matrix in nanometer scale. The dispersion and intercalation degree of the MCMMT platelets decreased with increase in the content of MCMMT. Under the same content of fillers, the tensile strength and tear strength of PU/MCMMT nanocomposites were higher than those of PU/organic MMT nanocomposites. The reinforcing effect of the MCMMT platelets to the PU was better than that of the organic MMT platelets. With increase in the content of MCMMT, the tensile strength and tear strength of the PU/MCMMT nanocomposites were increased, while the extent of the increase slowed down. Compared with those of PU, the thermal stability of PU/MCMMT nanocomposites was increased. Copyright © 2009 John Wiley & Sons, Ltd.     

高抗冲聚苯乙烯/蒙脱土复合材料的阻燃性研究

用经十六烷基三甲基溴化铵有机化改性的蒙脱土 (OMMT)与高抗冲聚苯乙烯 (HIPS)通过熔融插层法制备了HIPS OMMT复合材料 ,用X ray衍射技术对材料结构进行了表征 ,发现钠基蒙脱土 (Na+ MMT)和有机蒙脱土的层间距分别为 1 5 1nm和 2 18nm ,HIPS OMMT(5phr)复合材料中蒙脱土的层间距因聚合物大分子的插入扩大为 3 4 4nm ;而HIPS与Na+ MMT形成的复合材料的层间距与Na+ MMT的层间距相比却没有变化 ,表明未有机化处理土没有形成插层结构 .锥形量热仪的研究结果表明HIPS OMMT复合材料的热释放速率、质量损失速率以及生烟速率等燃烧特性参数均显著降低 ,具有较明显的阻燃性和抑烟性 ,而HIPS Na+ MMT非插层型复合材料只有在Na+ MMT很高填充量下 (>2 0phr)才有一定阻燃效果 .比较了铵盐对HIPS阻燃性的影响 ,结果表明铵盐自身的阻燃作用很小 ,主要是插层复合结构起阻燃作用 .     

Preparation and physicochemical properties of hydroxyapatite/polyurethane nanocomposites

In this study, nanohydroxyapatite/polyurethane （nHA/PU） composites with various contents of methoxy- poly（ethylene glycol） modified nHA （0 wt%, 10 wt%, 20 wt% and 30 wt%） were prepared by solution blending process. The physicochemical properties of the composite membranes were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffraction （XRD）, Transmission electronic microscopy （TEM）, Differential scanning calorimetry （DSC）, Thermo gravimetric analysis （TGA） and tensile tests. TEM photos of the nanocomposites showed that the nHA was uniformly dispersed in the polymer matrix. The membrane with 10 wt% nHA showed the highest tensile strength which was about 75% higher than that of the pure PU membrane. However, the tensile strength decreased when high content （above 20 wt%） fillers were added, which was still higher than that of pure PU. TGA measurements suggested that the thermal stability of the membranes was improved owing to nHA fillers. XRD and DSC results illustrated that the crystallinity of PU soft segments decreased with the increasing content of nanoparticles in the composites.