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聚氨酯是含有氨基甲酸酯链段的有机高分子材料。
聚氨酯（Polyurethane ，英文简称PU）是一种由多异氰酸酯和多元醇反应并具有多个氨基甲酸酯链段的有机高分子材料，其原材料可分为异氰酸酯类（如MDI 和TDI）、多元醇类（如PO 和PTMEG）和助剂类（如DMF）。
聚氨酯材料与传统材料性能比较：相比较材料聚氨酯性能优越之处金属材料重量轻、耐腐蚀、加工费用低、耐损耗、噪音低塑料耐磨、不发脆、具有弹性记忆橡胶耐切割、耐撕裂、高承载性、耐臭氧、透明或半透明、耐磨、可灌封、可浇注二、聚氨酯的上下游产业链（聚氨酯上游原料+ 聚氨酯下游制品）（一）聚氨酯上游原料（二）聚氨酯下游制品一个更具体的图三、聚氨酯产业链总结一个简单的图：聚氨酯弹性体：大分子主链上含有较多氨基甲酸酯基官能团（-NH-COO-）的弹性体聚合物，是由交替的软、硬段组成的多嵌段共聚物，其结构通式为(A-B)n。
其中A是相对分子质量500-3000的聚醚或聚酯多元醇，B为硬段，由异氰酸酯与小分子扩链剂（醇或胺）反应而成。
特别性能：耐磨、耐水、耐油、耐腐蚀、耐老化、耐辐射、耐低温、强度大，硬度和拉伸率可调范围宽。
是性能优良的塑料。
主要内容1、合成方法：一步法、预聚体法、半预聚体法。
2、原料：多元醇、异氰酸酯、扩链剂、催化剂、增塑剂、阻燃剂、填料。
3、弹性体种类：CUP（浇注型）TPU（热塑型）MPU（混炼型）4、决定弹性体性能的因素。
5、弹性体常见问题以及原因分析。
化学反应原理：①R-NCO+R’-OH=R-NHCOO-R’ （扩链反应）异氰酸酯醇聚氨酯②R-NCO+R’-NH2=R-NH-CO-NH-R’ （固化反应）异氰酸酯胺（扩链剂）脲③R-NCO+H2O =R-NH2+CO2 （发泡反应、原料含水）异氰酸酯水胺二氧化碳原料含水会发生③和②反应，即产生气泡又会使预聚体固化，即损坏设备，又破坏原料，因此原料含水要严格控制。
一步法预聚体法多元醇：聚酯：PEA（己二酸乙二醇酯）PCL（聚己内酯）聚醚：PTMG（四氢呋喃醚）PPG（聚丙二醇）聚碳酸酯多元醇：PCDL可用于弹性体、胶黏剂异氰酸酯：TDI、MDI、特殊异氰酸酯扩链剂：①胺类（TDI型弹性体）：MOCA（苏州湘园化工）、E-300端氨基聚醚②醇类（MDI型、胶黏剂里较多使用）：BDO、HQEE③醇胺类：三乙醇胺、三异丙醇胺催化剂：①叔胺类-催化异氰酸酯和水反应既发泡反应脂肪胺类、脂环胺类，芳香胺类、醇胺类常用的有三亚乙基二胺A33、二甲基氨基乙基醚A1、二甲基环己胺4#、DMP-30在弹性体内有胺类扩链剂存在下基本不使用催化剂。
聚甲丙烯酸铵酯和聚甲基丙烯酸甲酯概述说明以及解释1. 引言1.1 概述聚甲丙烯酸铵酯和聚甲基丙烯酸甲酯是两种常见的聚合物材料，具有广泛的应用领域。
它们在化学结构、物理性质以及应用方面存在一些差异。
本文旨在对这两种聚合物进行概述、说明和解释，并比较它们之间的区别。
1.2 文章结构本文将按照以下结构进行介绍：首先，我们将从概述开始，介绍聚甲丙烯酸铵酯和聚甲基丙烯酸甲酯的基本定义与性质；其次，我们将探讨它们在不同领域中的应用；最后，我们将详细描述制备这两种聚合物的方法。
此外，文章还将通过比较分析来揭示它们之间的区别与联系；最后，我们将得出结论并总结全文。
1.3 目的本文的目的是为读者提供有关聚甲丙烯酸铵酯和聚甲基丙烯酸甲酯的全面了解，并深入探讨它们在不同应用领域中的特点和用途。
同时，我们希望通过比较分析，准确地揭示这两种聚合物之间的区别，并为读者提供科学的参考和决策依据。
对于科研工作者、化学专业人员以及相关领域从业者而言，本文将是一份有价值的资料和信息源。
以上为文章“1. 引言”部分的内容。
2. 聚甲丙烯酸铵酯：2.1 定义与性质：聚甲丙烯酸铵酯，简称PAMAMPS，在化学上属于离子型高分子。
它是由聚合物化学方法得到的一种阳离子型聚合物，具有较高的溶解性和水溶润性。
PAMAMPS的主要特点是其极性较大，可以在水中迅速成溶润状态。
2.2 应用领域：PAMAMPS广泛应用于许多领域，如纺织品、造纸、油田、污水处理等。
在纺织工业中，PAMAMPS被用作染料和助剂的固定剂，以提高染料的渗透性和固着性。
在造纸工业中，PAMAMPS可作为湿强剂和防止纤维粉末结块的抗结剂使用。
此外，在油田领域，PAMAMPS也被广泛应用于增加原油开采率、改善注入液稳定性等方面。
2.3 制备方法：制备PAMAMPS主要通过反应聚合法进行。
一般通过将甲基丙烯酸铵与其他单体进行共聚反应，得到具有正电荷的PAMAMPS。
此外，可以通过离子交换反应将甲基丙烯酸甲酯改性为PAMAMPS。
pmma合成路线-回复PMMA（聚甲基丙烯酸甲酯）是一种常见的合成聚合物材料，具有优异的光学性能、耐化学腐蚀性和机械强度。
今天，我们将介绍一种常用的PMMA 合成路线，以帮助读者了解和理解该材料的制备过程。
1. 材料准备在合成PMMA之前，我们需要准备一些基础的原料和试剂。
这些材料包括甲基丙烯酸甲酯（MMA）、过硫酸铵（APS，引发剂）、反应容器、溶剂（如甲苯）、稳定剂和控制剂等。
这些材料可以在化学试剂商店或供应商处购买。
2. 反应条件为了成功合成PMMA，我们需要控制一些重要的反应条件。
首先，反应需要在惰性气体（如氮气）下进行，以避免空气中的氧气和水对反应的干扰。
其次，我们需要控制反应的温度，常用的范围是60-100摄氏度。
最后，我们需要确保反应容器的密封性良好，以避免材料外泄和试剂浪费。
3. 反应步骤开始合成PMMA之前，我们需要在反应容器中加入适量的溶剂（如甲苯），以保持反应体系的流动性。
然后，我们将甲基丙烯酸甲酯（MMA）缓慢地滴加到溶剂中。
同时，在另一个容器中配置一定浓度的过硫酸铵（APS）溶液作为引发剂。
一旦所有试剂都添加到反应容器中，我们需要搅拌反应体系以促进反应的进行。
在反应过程中，过硫酸铵（APS）将分解生成自由基，引发甲基丙烯酸甲酯（MMA）的聚合反应。
这种聚合反应会不断进行，直至反应物完全消耗。
4. 反应监控在反应过程中，我们可以使用红外光谱（IR）和核磁共振（NMR）等测试技术来监控反应进程。
通过检测反应物的消耗和产物的形成，我们可以掌握聚合反应的进行情况，并调整反应条件以达到预期的合成目标。
5. 稳定处理合成得到的PMMA通常需要经过稳定处理，以提高其热稳定性和耐候性。
我们可以添加适量的稳定剂和控制剂到PMMA中，通过热处理或光照处理使其充分混合和稳定。
总结通过以上步骤，我们可以成功合成PMMA。
这种合成方法被广泛应用于工业生产中，可以生产出高质量、高性能的PMMA材料。
聚甲基丙烯酸甲酯聚甲基丙烯酸甲酯（Poly(methyl methacrylate)简称PMMA）是一种广泛应用的聚合物材料。
它具有优异的透明度、高强度和良好的耐候性等特点，被广泛应用于建筑、汽车、光学器件等领域。
本文将从聚甲基丙烯酸甲酯的制备方法、物性表征以及应用领域等方面进行介绍。
一、聚甲基丙烯酸甲酯的制备方法1. 逐步聚合法：首先将甲基丙烯酸甲酯单体与引发剂加入反应釜中，经过一系列的反应步骤，得到聚合物。
这种方法常用于小规模的实验室制备。
2. 均相聚合法：在适当的溶剂中，将甲基丙烯酸甲酯单体与引发剂进行均相溶液聚合。
该方法适用于大规模生产，能获得更高的聚合度和更均匀的分子量分布。
3. 残留体系聚合法：通过将甲基丙烯酸甲酯单体与引发剂固定在聚合剂载体上，通过体系热解或紫外辐射等方式来释放聚合物。
这种方法能够实现可控的聚合反应，得到具有特定结构的聚甲基丙烯酸甲酯。
二、聚甲基丙烯酸甲酯的物性表征1. 透明度：聚甲基丙烯酸甲酯具有优异的透明度，其透明度与玻璃相当，而密度只有玻璃的一半。
这使其广泛应用于自动车窗、光学仪器和观察窗等领域。
2. 强度：聚甲基丙烯酸甲酯具有较高的强度，比普通玻璃更耐冲击，减少了由于碎裂而造成的伤害。
3. 耐候性：聚甲基丙烯酸甲酯具有良好的耐候性，不易受紫外线照射、湿度、高温等环境因素的影响。
因此，它常用于室外标牌、车身配件等需要耐候性的领域。
4. 气密性：聚甲基丙烯酸甲酯具有很好的气密性，能够有效阻挡氧气和水蒸气的渗透，保护容器内部物品的质量。
三、聚甲基丙烯酸甲酯的应用领域1. 建筑领域：聚甲基丙烯酸甲酯常用于建筑领域中的采光板、隔热材料和玻璃替代品等产品。
其透明度和强度使其成为理想的建筑材料之一。
2. 汽车领域：在汽车制造过程中，聚甲基丙烯酸甲酯被广泛应用于车窗、后视镜、仪表盘等部位。
其高强度和耐候性保证了汽车零部件的长期使用。
3. 光学器件：由于其透明度和光学性能，聚甲基丙烯酸甲酯在光学器件领域有着广泛的应用。
聚甲基丙烯酸甲酯（PMMA）物料性能模具设计制造商及品牌发展历史1. 1927年德国罗姆—哈斯的化学家研发了丙烯酸酯及甲基丙烯酸甲酯的聚合。
2. 1931年德国的罗姆－哈斯公司首先建厂生产PMMA，取代了赛璐珞用作飞机座舱罩和挡风玻璃。
3.1936年英国卜内门化学工业公司开发了悬浮聚合法生产PMMA。
物料性能结构式是一种非结晶性聚合物，因其良好的透光性能，又称有机玻璃，密度1.14-1.20g/cm3，比重1.19。
它不但具有很高的透光率（92％），而且机械强度高，重量轻、耐紫外线和户外老化，优良的电性能等特点。
不足之处是耐热性差、冲击强度不高，尤其对缺口冲击敏感等。
1. 一般性能：是一种外观透明的聚合物，所有透明塑料中最佳的透光率（3毫米厚度92%透光率），经冲击改性后的透明度会有些降低。
极低的雾化度。
2. 机械性能：机械强度比普通玻璃高10倍以上，但和其它塑料相比强度只能算中等。
表面硬度与铝材接近，在所有透明塑料中是最高的。
它的缺点是质轻脆、易开裂（或出现银纹）。
卓越的抗磨性能，用指甲无法划伤。
3. 热性能：耐热性不够好，使用温度仅80℃。
可通过其单体与双酯基丙烯酸乙二醇酯或甲基丙烯酸丙烯酯等共聚、交联，以提高耐热性。
比热比大多数热塑性塑料都低，有利于它快速受热塑化。
另外它还具有一定的耐寒性，在低温-50-60℃下，冲击强度变化很小。
4. 电性能：电性能良好，特别是在低频率工作条件下。
某些电性能是独特即介电损耗角正切值随频率的升高而降低。
温度和频率对介电常数有影响，而气候和湿度对电性能的影响不大。
但电性能比PE、PS等差。
5. 防火性能：防火性能一般，防火等级一般为UL94 HB。
6. 耐候性：具有优良的耐候性，在热带气候下暴晒多年透明度和色泽变化很少。
7. 可抵抗的化学物质：稀酸、碱类、非氧化性酸类、盐类、非极性、非芳香族之有机溶剂、油脂等。
8. 不可抵抗的化学物质：二氯甲烷，氯仿，四氯化碳，苯，甲苯，二甲苯，丙酮，丁酮，甲醇，乙醚，浓氧化酸、溶于大多数芳香族及氧化碳氢、酯酮等。
Preparation,structure and properties of polyurethane/poly (methyl methacrylate)/organo2montmorillonite nanocomposites3FU Li2hua,J IA De2min,L IU Sa(Depart ment of Polymer Materials Science and Engineering,South China U niversity of Technology,Guangzhou510640,China) Abstract:In this paper,the intercalation technique and interpenetrating polymer networks method were first used together to pre2 pare polyurethane/poly(methyl methacrylate)/organo2montmorillonite(PU/PMMA/OMM T)nanocomposite.The structure and morphology of polyurethane(PU),interpenetrating polymer network based on polyurethane and poly(methyl methacrylate)(PU/ PMMA2IPN),polyurethane/organo2montmorillonite(PU/OMM T)and PU/PMMA/OMM T systems were comparatively inves2 tigated by X2ray diff raction(XRD)and scanning electron microscopy(SEM).The results show that organo2montmorillonite (OMM T)is well dispersed in polymer matrix with particles of20～80nm in PU/PMMA/OMM T system,which confirms the in2 terecalated nanocomposite is formed.PU/OMM T is interecalated nanocomposite because the d2spacing of OMM T increased and the OMM T is uneven dispersed in polyurethane matrix with the tactoids of40～700nm.The introduce of OMM T into PU/PM2 MA2IPN system makes the plastic domain size increased and the microphase seperation more obviously between PU and PMMA phases.The results of thermogravimetric analyses(T GA)indicate that the thermal stability of PU/PMMA/OMM T nanocom2 posite is better than that of PU/PMMA2IPN and PU/OMM T nanocomposite because the phase structure has been improved and the intercalation of OMM T increased1.5times.Additionally,the mechanical properties of PU/PMMA/OMM T nano2 composites are superior to those of other comparative systems. K ey w ords:polyurethane;montmorillonite;poly(methyl methacrylate);interpenetrating polymer netw orks;nanocomposite C LC number:TB33 Document code:A Article ID:100129731(2005)1021638207 1 IntroductionPinnavaia[1]and coworkers first reported t he superior polyuret hane/mont morillonite(PU/MM T)nanocom2 posites,which att racted t he attention of researchers because of t he unprecedented suite of new and enhanced p roperties relative to p ure polyuret hane or conventional compo sites.At p resent,two main met hods,direct in2 tercalation and solution intercalation[2,3],were used to prepare PU/MM T nanocomposites.The nanocomposites often exhibit remarkable improvement s in mechanical[4～6],t hermal[7,8],t ransport[9,10]and barrier[11]properties wit h a low loading of clay in t he polymer mat rix because of t he good compatibility and st rong interaction be2 tween polyuret hane and mont morillonite.However,t he direct intercalation met hod needed t he rigorous reactive conditions,which was difficult in co nt rolling t he polymerization and t he p roduct properties.The solution inter2 calation met hod needed vast solvent,which brougt about complex process and high cost.Thus it is necessary to develop a novel and simple met hod to modify t he PU/MM T nanocomposites.Interpenet rating polymer networks(IPNs)were a kind of unique polymer blends consisting of two or more cro ss-linked polymers held toget her by interpenetration and entanglement of t he networks[12,13],which had at2 t racted attention of researchers because of t he synergism for p roperties[14～18].The IPNs systems containing PU as one network obtained t he most interest.The IPNs can be divided into two major categories,depending on t heir synt hesis type:sequential IPNs where t he monomers,cross2linking agent s,and initiators of network II were swollen into polymer network I and reacted in sit u;and t he simultaneous interpenet rating networks (SINs),where t he different monomers or propolymers for bot h networks were mixed and polymerized simulta2 neously.IPNs met hod has t he remarkable merit s,for example,t he initial viscosity of t he system is low and it can be p rocessed easily which can benefit to nano2intercalating of PU/MM T nanocompo sites.In t his st udy,t he nano2intercalating technique and met hod of IPNs were first used toget her to prepare PU/ PMMA/OMM T nanocompo sites by t he met hod of simultaneous intercalating polymerization.In t he reactive system,met hyl met hacrylate toget her wit h t he crosslinking agent,et hylene glylene dimet hacrylate(EGDMA)3Found ation item:Supported by Guangdong Provincial Natural Science Foundation for Group Project(39172) R eceived d ate:2005206220Modif ied d ate:2005208223 Corresponding author:FU Li2huaBiography:FU Li2hu a (1977-),female,Ph.D.,major in the systhesis and modification of polymer.was int roduced as active solvent for PU/MM T nanocompo sites,which can effectively solve t he p roblem of recy2 cling solvent and improve t he p rocessing met hod.Additionally,polyuret hane based on liquid4,42dip henyl2 met hane diisocyanate(L MDI)and polytet ramet hylene glycol(P TM G),PU/PMMA2IPN and PU/OMM T nanocompo site were prepared and t heir struct ure and p roperties were compared wit h PU/PMMA/OMM T.The st ruct ures and morp hologies were inspected by XRD and SEM.The t hermal properties were investigated by T GA.Their mechanical p roperties were also st udied.2 Experimental2.1 R a w materialsP TM G wit h number average molecular weight about2000g/mol and hydroxyl number about56mg KO H/g (Dupont)was degassed for2h at110℃under vacuum to remove moist ure before use.Met hyl met hacrylate (MMA;C.P.grade)was washed wit h10%NaO H solution and distilled water,t hen dried wit h0.5nm zeolite before use.Benzoyl peroxide(B PO;C.P.grade)was recrystallized before use.EGDMA(indust rial grade)was dried wit h0.5nm zeolite before use.1,42butanediol(BDO;C.P.grade)was distilled under vacuum to remove moist ure and dried wit h0.5nm zeolite before use.L MDI of MM103(Bayer Company)was used as received. Sodium based mo nt morillonite(NaMM T)wit h ion2exchange capacity of100mequiv/100g was p urchased f rom Nanhai Nonmetals Minerals Co.(China).OMM T was prepared wit h acidified ocamidopropyl betaine(CAB)in our laboratory according to reference[19].The ot her inorganic and organic reagent s were available commercially.2.2 Preparation ofThe mixt ure of L MDI and P TM G at molar ratio of2.4∶1was heated to80℃for2h to form an isocyanate terminated polyuret hane p repolymer which was vacuum degassed at80℃until t here was no gas in it.The stoi2 chiomet ric BDO was added to t his prepolymer at90℃under stirring wit hin several minutes,t hen t he mixt ure was poured into a metal mold,cured at110℃for24h,placed at ambient temperat ure for one week before test.2.3 Preparation of PU/OMMT nanocompositesThe stoichiomet ric mixt ure of P TM G and OMM T was heated to60℃under rapid stirring for24h.The L MDI wit h2.57molar times of P TM G was added to t he mixt ure of P TM G and OMM T,t hen t he new mixt ure was heated to80℃for2h to form an isocyanate terminated polyuret hane prepolymer wit h OMM T which was vacuum degassed at80℃until t here was no gas in it.The stoichiomet ric BDO was added to t his prepolymer at 90℃under rapid stirring wit hin several minutes,t hen t he mixt ure was poured into a metal mold,cured at110℃for24h,placed at ambient temperat ure for one week before test.2.4 Preparation of PU/PMMA2IPNThe mixt ure of L MDI and P TM G at molar ratio of2.4∶1was heated to80℃for2h to form an isocyanate terminated polyuret hane prepolymer.The isocyanate terminated polyuret hane prepolymer was evenly mixed wit h BDO,MMA,EGDMA,BPO and N,N2dimet hylaniline(DMA)at stoichiomet ric weight ratios in a reac2 tion kettle at ambient temperat ure.Then t he last mixt ure was degassed at vacuum for several minutes,poured into a metal mold,reacted at ambient temperat ure for about10h,cured at110℃for24h,placed at ambient temperat ure for one week before test.2.5 Preparation of PU/PMMA/OMMT nanocompositesThe stoichiomt ric P TM G,OMM T and MMA were blended by ult rasonic inst rument at ambient tempera2 t ure for30min.The L MDI wit h2.63molar times of P TM G was added to t he mixt ure of P TM G,OMM T and MMA,t hen t he new mixt ure was heated to80℃for2h to form an isocyanate terminated polyuret hane p repoly2 mer wit h OMM T as well as MMA.The stoichiomet ric MMA,BDO,EGDMA,B PO and DMA were added to t his prepolymer in a reaction kettle.The whole mixt ure was t horoughly blended at ambient temperat ure quickly and vacuum degassed wit hin several minutes,t hen t he mixt ure was poured into a metal mold,reacted at a cer2 tain temperat ure for about10h and cured at110℃for24h and placed at ambient temperat ure for one week be2 fore determination.2.6 MeasurementTensile st rengt h,elongation at break and tensile modulus were measured according to G B/T52821998wit h U T22060elect ronic universal testing machine at ambient temperat ure at a cross-head speed of(500±50)mm/min.Tear st rengt h was measured according to G B/T52921999wit h U T22060elect ronic universal testing ma2 chine at ambient temperat ure at a cross2head speed of(500±50)mm/min.Shore A hardness was performed ac2 cording to G B/T53121999wit h shore A sclerometer at ambient temperat ure.XRD measurement s on t he powder samples and nanocompo sites slices were performed wit h a D/MA X2Ⅲpowder diffractometer equipped wit h Cu Kαradiatio n(λ=15.4nm).SEM measurement s were performed wit h an XL230FEG scanning elect ron micro2 scope by Phillp s.Samples were prepared by f ract uring t he specimens at liquid nit rogen temperat ure and were gold2coated.T GA of samples were carried out under N2at mo sp here on an American TA Inst rument s Modulated T GA2050at a heating rate of10℃/min.3 R esults and discussion3.1 Structure and morphology of different systemsThere were t hree kinds of polymer2layered silicate nanocomposites:intercalated,intercalated/exfoliated and exfoliated nanocompo sites[20].XRD was an effective met hod for t he evaluation of t he intercalation capability of polymers.The expansion of layers of organoclay can be detected by XRD.And t he interlayer spacing(d2 spacing)value of clays can be obtained f rom t heir characteristic diffraction peaks of t he(001)plane,based on Bragg’s equation,which made t he intercalation capability of polymers numerable.In intercalated nanocompo s2 ites,t he characteristic diffraction peak shifted toward lower diffraction angle.In exfoliated nanocomposites,no characteristic diff raction peak could be obtained.However,in intercalated/exfoliated nanocomposites,whet hert he characteristic diffraction peak appeared or not it would depend on t he exfoliateddegree.Fig1XRD patterns of different sys2 tem and OMM T The XRD patterns of different systems and OMM T were shown in Fig1.It can be seen t hat OMM T has a strong characteris2 tic diff raction peak when2θ=2.46°,corresponding d2spacing value is3.65nm.The sample of PU/OMM T exhibit s a weak characteris2 tic diff raction peak when2θ=2.12°,corresponding d2spacing value is4.16nm,which indicates t hat PU/OMM T be intercalated nano2 composite.This result can be obviously comfirmed by TEM image of PU/OMM T in Fig3(b)also.However,t here is no obviously diffraction peak wit hin small angle for PU/PMMA/OMM T.This result may relate to t he reason t hat d2spacing value of OMM T is out of t he capability of apparat us.This result suggest s t hat t he intercalation capability of PU/PMMA/OMM T be better t han t hat of PU/OM2 M T.Because t he mo nomer of MMA and EGDMA as active solvent dilutes t he mixt ure of P TM G and OMM T, which makes OMM T dispersed well in t he mixt ure.And it makes more P TM G intercalating into t he interlayers of OMM T so t hat t he d2spacing value of OMM T becomes larger.When L MDI was added to t he system a por2 tion of L MDI intercalates into interlayers of OMM T because of t he larger d2spacing and t he reaction between L MDI and P TM G or OMM T.This increases d2spacing value of OMM T f urt her or even makes t he particles of OMM T exfoliated.Therefore,t here is no obviously diffraction peak wit hin small angle for PU/PMMA/OMM T because d2spacing value of OMM T is out of t he capability of apparat us.Therefore,t he comp rehensive p roper2 ties of t he system can be sharply improved,for example,t he t hermal stability and mechanical p roperties have bot h been imp roved as shown in following part s.Additio nally,t hey(PU,PU/OMM T,PU/PMMA2IPN and PU/PMMA/OMM T)all p resent a wide diffraction peak wit h2θrange from～10°to30°.The result s suggest t hat t here are short2haul arrangement in sequence of molecular chains in t hese systems[21].Furt her evidence of nanometer2scale dispersion of MM T and p hase st ruct ure in t he case of PU/PMMA/OMM T will be supported by SEM images as shown in Fig2. The dispersio n of MM T in polymer mat rix and t he p hase st ruct ure were investigated by SEM images as showed in Fig2.It can be seen f rom Fig2(a)and(b)t hat t here are no obvio us microp hase seperation bot h in PU and in PU/OMM T,and t hat OMM T in polymer mat rix is broken into t he tactoids wit h uneven dist ribution in size of40～700nm due to t he high viscosity in PU/OMM T system.It can be seen f rom Fig2(c)t hat many white particles wit h t he size of40～450nm are dispersed in polyuret hane mat rix.PU p hase will be continuousp hase in PU/PMMA2IPN system because t he formation speed of PU is bigger t han t hat of PMMA.Therefore t ho se white particles represent PMMA particles and t here is no obvious microp hase seperation in PU/PMMA2 IPN system.It can be seen f rom Fig2(d)t hat rupt ure surface p resent s wavily.This result suggest s t hat t here be microp hase seperation between PU and PMMA p hases in PU/PMMA/OMM T system.Wave crest repre2 sent s PU p hase,mainly continuo us p hase and t rough rep resent s PMMA p hase.When OMM T is dispersed in PU/PMMA2IPN system,t he organic modifier makes t he interface energy decreasing and t he hygrogen bonding forms between t he polar group s of OMM T and hard segment s of PU or C O of PMMA.This will lead to t he size of hard segment s of PU or PMMA domain p hase increasing.Many white particles wit h t he size of20～80nm and holes wit h t he size of50～450nm are mo stly dispersed in t he interface between PU and PMMA p ha2 ses,few in PU and PMMA p hases.As we known t hese holes form when t he mont morillonite was p ulled out f rom t he polymer matrix because t here was st rong interaction between MM T and t he polymer matrix.The dis2 persions of t he white particles and holes are similar,which suggest s t hat t hese white particles represent MM T. The OMM T in PU/PMMA/OMM T nanocompo site is dispersed well into t he polymer mat rix and breaks into smaller tactoids wit h even dist ributio n in size compared to PU/OMM T because of t he dilution of MMA and EGDMA.Fig2SEM images of different systems3.2 Therm al properties of PU/PMMA/OMMT nanocompositeThe t hermal stability of PU/PMMA-IPN,PU/OMM T and PU/PMMA/OMM T systems was investiga2 ted by T GA and D T G shown in Fig3and Fig4,which p rovided some important data such as temperat ure at weight loss of5%,t he peak temperat ures of t he first degraded stage,t he second stage and t he t hird stage de2 fined as T d,T1max,T2max,and T3max,respectively,as shown in Table1.As reported in previous st udy[8],t he enhancement of t he t hermal durability of polyuret hane by silicates has rarely been demonst rated.In terms of t hermal properties,t he modifier of MM T often remained in t heir original chemical struct ures(low molecular weight)in t he nanocompo sites,and t herefore p roduced a negative effect on t he t hermal resistance of t he nanocompo sites.From Fig3,it can be seen t hat t he int roduce of OMM T to PU/ PMMA2IPN makes t he t hermal durability improved obviously compared PU/PMMA2IPN to PU/PMMA/OM2M T nanocom2po site. Fig3T GA curves of different systems Fig4D T G curves of different systemsT able1Important data obtained from Fig3and4T d(℃)T d50%(℃)T1max(℃)T2max(℃)T3max(℃)Residue at550℃(%)PU/OMM T310.3403350.4410.89.7PU/PMMA2IPN301.5391.7351.3404.0 5.7PU/PMMA/OMM T318.0412.5351.8418.29.4 From Fig3and4,it can be seen t hat PU/OMM T nanocomposite degrades wit h p rocedure in t hree stages, as reported in p revious st udies[8,22],t he first stage(253～368℃)is dominated by t he degradation of t he hard segment of PU and t he modifier of MM T(CAB),T1max is350.4℃,t he second stage(368～461℃)correlates well wit h t he dissociation of t he soft segment,T2max is410.8℃,f rom XRD result t he t hird stage(461～491℃) may result f rom t he degradation of t he intercalated molecular chains,t he corresponding weight loss is1.4%. And t he residue at550℃of PU/OMM T is9.7%.Fro m Fig3and4,it can be seen t hat PU/PMMA2IPN sys2 tem degrades wit h p rocedure in two stages,as reported by Gradwell[23],t he first stage(241～370℃)is domina2 ted by t he degradation of t he hard segment,T1max is351.3℃,t he second stage(370～463℃)correlates wit h t he dissociatio n of t he soft segment and PMMA chains,T2max is404.0℃.And t he residue at550℃of PU/PMMA2 IPN is5.7%.However,t he degradation of PU/PMMA/OMM T involves in five stages.From SEM result t hat t here is microp hase seperation between PU and PMMA p hases in PU/PMMA/OMM T nanoco mposite,t he first stage(276～374℃)may be do minated by t he degradation of t he hard segment of PU in PU p hase and t he modi2 fier of MM T(CAB),which is similar to t he first stage of PU/OMM T,T1max is351.8℃,a little higher t han t hat of PU/OMM T,which may result from t he tanglement between a little PMMA and PU in PU p hase.The second stage(374～383℃)may correlate wit h t he dissociation of t he hard segment of PU in PMMA p hase,t he dissociatio n temperat ure is higher t han t hat in PU p hase because t here is bigger content of PMMA in PMMA p hase so as to more tanglement.The t hird stage(383～445℃)correlates wit h t he dissociation of t he soft seg2 ment of PU in PU/PMMA/OMM T and PMMA chains only in PU p hase,T3max is418.2℃,which is similar to t he second stage of PU/PMMA2IPN but t he degradation temperat ure range becomes wider and t he peak temper2 at ure of t his stage increases14.2℃,t hese result s may result f rom t he tet hered OMM T served as a t hermal bar2 rier delaying t hem fro m degradation during heated.The fourt h stage(445～471℃)may correlate wit h t he dis2 sociatio n of PMMA chains in PMMA p hase,T4max is about450.7℃,which is similar to t he two stage of PMMA degradatio n[24],t he peak temperat ure of t his stage increases10.5℃because of t he tanglement wit h PU.The fift h stage(471～533℃)may result f rom t he degradation of t he intercalated molecular chains,t he correspond2 ing weight lo ss is2.9%,t he degree of intercalation is2.1times compared to t hat of PU/OMM T.And t he resi2 due at550℃of PU/PMMA/OMM T is9.3%.Compared to t hat of PU/PMMA2IPN,t he value increases3. 5%.OMM T may cont ribute some2.0%.The result s confirmed t here be tanglement between PU and PMMA again.Therefore,we can conclude t hat int roduce of OMM T to IPN makes t he t hermal properties dramatically improved and makes t he degree of microp hase seperation increased.3.3 The mechanical properties of PU/PMMA/OMMTIn t his paper,PU,PU/PMMA2IPN,PU/OMM T and PU/PMMA/OMM T systems were st udied in order to investigate t he effect of OMM T on mechanical p roperties of PU/PMMA2IPN.The mechanical properties of t hese materials were shown in Table2.T able2Mechanical properties of different systemsPU PU/OMM T PU/PMMA2IPN PU/PMMA/OMM T 100%tensile modulus(MPa) 3.8910.4615.6916.06300%tensile modulus(MPa)7.6818.4523.24tensile strength(MPa)16.5518.4517.5430.65elongation at break(%)380300170350tensile permanent set(%)16364020tear strength(kN/m)43.2647.3051.6378.91shore A hardness72787465 Note:NCO content of PU prepolymer is4.45%,PU/PMMA=60/40,OMM T,BPO and EG DMA contents are5%,0.8%and2.0%of MMA weight,respectively,the coefficient of BDO is0.8. It can be seen f rom Table2t hat100%modulus,tensile st rengt h,tear st rengt h,permanent set and shore A hardness increase,while elongation at break decreases when PU is modified by OMM T.These result s may be associated wit h t he reasons shown as following:in PU/OMM T,OMM T particles are broken into t he tactoids wit h uneven dist ributio n in sizes of40～700nm in PU mat rix(shown as SEM images in Fig2);as st ress focus point s,t hese tactoids make elo ngation at break decrease,permanent set and shore A hardness increase.Addi2 tionally,t he OMM T of tactoids’surface is intercalated(shown as XRD curve in Fig1and T GA),which makes 100%modulus,tensile st rengt h and tear st rengt h of PU increase.By t he met hod of IPNs,it can be seen f rom Table2t hat100%modulus,tensile st rengt h and tear st rengt h increase,which is att ributed to tanglement be2 tween PU and PMMA,but permanent set and shore A hardness increase,and elongation at break decreases sharply because of t he rigidity of PMMA.When PU/OMM T is modified by IPN met hod,100%modulus,ten2 sile strengt h,elongation at break and tear strengt h of PU increase f rom10.46,18.45M Pa,300%and43. 26kN/m to16.06,30.65M Pa,350%and78.91kN/m,and permanent set and shore A hardness decrease f rom 36%and78to20%and65,respectively.These result s indicate t hat t he mechanical p roperties of PU/OMM T system have been dramaticly improved by IPN met hod.The reasons may be shown as follows.OMM T disper2 ses well in PU/PMMA/OMM T system,which is confirmed by XRD and SEM,and P TM G as well as MMA can intercalate more easily into t he interlayers of OMM T,which is confirmed by XRD and T GA.When L MDI is added to t he system a portion of L MDI is intercalated into interlayers of OMM T because t he larger d2spacing and t he reaction between L MDI and intercalated P TM G or OMM T,which increases t he d2spacing of OMM T f urt her or even makes t he particles of OMM T exfoliated.When BPO is added in t he system,intercalating MMA would in sit u polymerize in interlayers of OMM T,which will increase t he d2spacing of OMM T or even make t he particles of OMM T exfoliated.Therefore,t he mechanical p roperties of PU/OMM T have been sharply im2 proved.4 ConclusionsPU/PMMA/OMM T nanocompo site was p repared by synchronous intercalated polymerization based on t he nano-intercalating technique and t he IPN met hod toget her.PU/OMM T is t he interecalated nanocomposite be2 cause t he d2spacing increases and t he OMM T is uneven dispersed in polyuret hane mat rix wit h t he tactoids of40～700nm.PU/PMMA/OMM T is t he interecalated nanocompo site because t he OMM T particles of20～80nm lengt h are dispersed well in polymer matrix and t he intercalation degree is2.5times related to t hat of PU/OM2 M T.The int roduce of OMM T into PU/PMMA2IPN system makes t he plastic p hase size increase and t he mi2 crop hase seperation more obvious between PU and PMMA p hases.The result s of T GA indicate t hat t he t hermal stability of PU/PMMA/OMM 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