抗盐性阳离子聚丙烯酰胺助留剂的应用探讨(完整版)实用资料

抗盐性阳离子聚丙烯酰胺助留剂的应用探讨（完整版）实用资料(可以直接使用，可编辑完整版实用资料，欢迎下载）

№.3陕西科技大学学报Jun.2021抗盐性阳离子聚丙烯酰胺助留剂的应用探讨（完整版）实用资料(可以直接使用，可编辑完整版实用资料，欢迎下载）・46・JOURNALOFSHAANXIUNIVERSITYOFSCIENCE&TECHNOLOGYVol.273文章编号:1000-5811(20210320046205抗盐性阳离子聚丙烯酰胺助留剂的应用探讨袁广翔,戴红旗,王淑梅,王忠良(南京林业大学江苏省制浆造纸科学与技术重点实验室,江苏南京摘要:研究了由阳离子单体(DADMACAM2二甲基二烯丙基氯化铵(MPAM助留剂的助留助滤性能.:μs/cm以下,阳离子聚合物的相,;电导率在3000μs/cm以上,聚合物电荷,而其相对分子质量高低的影响成为次要因素.在较高电导率、,高阳电荷密度的MPAM有比CPAM更好的助留助滤效果.关键词:MPAM;电导率;DCS;助留助滤中图分类号:TS727+.2文献标识码:A0引言随着造纸白水循环回用的比例越来越大,吨纸耗水量在不断降低,由此造成湿部系统大量的细料、无机盐(电导率升高及阴离子干扰物的积累,进而削弱了原先正常工作的CPAM助留系统对细小纤维及填料等的助留以及对纸料的助滤效能.阳离子线性高分子聚合物CPAM具有对纸料优良的架桥絮聚功能特性,是目前造纸系统不可或缺的造纸化学助剂,但因为白水封闭循环系统中积累的水溶性无机盐将引起电导率上升,而高电导率影响作用下线性高分子聚合物分子链会收缩与卷曲,从而降低线性高分子对带相反电荷物质的架桥絮聚功能.聚二甲基烯丙基氯化铵(PDADMAC具有阳电荷密度高、稳定性好及抗盐性强的特点,但其相对分子质量相对较低,一般只能作为湿部系统的阴离子干扰物控制剂或助滤剂使用[1212].根据PDADMAC和CPAM的各自优点,本实验室将阳离子单体(DADMAC与丙烯酰胺单体(AM按一定比例通过水相游离基聚合方式制备了聚2丙烯酰胺2二甲基二烯丙基氯化铵(MPAM高分子聚合物,MPAM的粘均相对分子质量为229.6万,阳电荷密度为2.45meq/g,下面就其抗盐性能及阴离子干扰物影响下的助留助滤性能进行研究比较.1实验1.1主要原料CPAM(汽巴精化,粘均相对分子质量401.5万,阳电荷密度2.01meq/g;MPAM(本实验室研制,粘均相对分子质量229.6万,阳电荷密度2.45meq/g;阴离子垃圾(DCS模拟物:氧化淀粉溶液,阴离子松香酸溶液,丁苯胶乳溶液,碱木素溶液;阔叶木浆(巴西金鱼牌;填料碳酸钙;膨润土PC27.1.2浆料滤水性能的测定取含3g绝干浆(含碳酸钙填料25%的1000mL浆料加入动态滤水仪中,用氯化钠溶液调节电导率3收稿日期:2021-03-26作者简介:袁广翔(19822,男,江苏省南京市人,在读博士生,研究方向:造纸化学与工程基金项目:国家自然科学基金项目(30871995和南京林业大学江苏省制浆造纸科学与技术重点实验室开放基金(202118资助课题第3期袁广翔等:抗盐性阳离子聚丙烯酰胺助留剂的应用探讨或添加DCS模拟物,充分混合均匀后,加入助留剂CPAM或MPAM.在1500r/min的转速下搅拌1min,然后在750r/min下加入用量为0.2%的膨润土,搅拌10s,用标准加拿大游离度仪测纸料游离度.1.3纸料细小组分留着率测定取含3g绝干浆(含碳酸钙填料25%的1000mL浆料加入动态滤水仪中,用氯化钠溶液调节电导率或添加DCS模拟物,充分混合均匀后,加入助留剂CPAM或MPAM.在1500r/min的转速下搅拌1min,然后在750r/min下加入用量为0.2%的膨润土,搅拌10s,收集前30s的滤液,称重、过滤、烘干、恒重并计算.细小组分留着率R的计算公式:R=[12W×(/T式中:T2纸料中细小组分质量(g;V2(W前滤液中细小组分质量(g;u230s后收集滤液重量(g.2结果与讨论2.1电导率对CPAM和MPAM助留助滤性能的影响电导率不仅影响到助留剂高分子的带电性质和构象,而且也影响到纸料各组分的表面化学特性.因此,为探讨电导率对纸料留着和滤水性能的影响,比较商品CPAM与自制MPAM的应用效果,本实验选择Hydrocol助留系统作为标准助留系统,即CPAM+膨润土或MPAM+膨润土.研究所准备的纸料含25%碳酸钙填料,商品CPAM或MPAM的用量为0.02%,膨润土用量为0.2%,改变纸料电导率,测定纸料细料留着率和游离度,结果如图1和图2所示.图1电导率对助留剂助留性能的影响图2电导率对助留剂助滤性能的影响从图1、图2可见,随着电导率的不断升高,纸料中细料的留着率及滤水性在不断下降,且CPAM对纸料助留及助滤效果下降幅度明显大于MPAM,电导率从初始值增大到5140μs/cm,由CPAM作为助留剂的纸料细小组分留着率从75.1%降到了68.61%,纸料游离度由340mL下降到210mL;而使用MPAM时,纸料中细小组分留着率从72.7%降到71.52%,游离度由290mL降低到250mL.从图1和图2还发现,在纸料电导率3000μs/cm以内,CPAM的助留及助滤效果好于MPAM,但当电导率超过3000μs/cm时,MPAM对纸料的助留及助滤效果则好于CPAM.这表明纸料电导率升高,影响到了高分子聚合物的助留及助滤性能,尽管商品CPAM的相对分子质量大约为MPAM的2倍,应该有更强的架桥絮聚能力,但实验结果表明并非如此.因此,可以得到这样的结论:在电导率3000μs/cm以内,阳离子聚合物助留剂的相对分子质量越大,其助留及助滤效果越好;而当电导率超过3000μs/cm以上时,聚合物相对分子质量高低影响作用变为次要,电荷密度高低的主导作用开始显现.这也许是在低电导率下聚合物分子链在水中较为舒展,绝大部分阳离子官能团暴露在外,更易吸附细小纤维及填料,并起到较好的架桥絮聚效果.相反,在高电导率情况下,系统中因存在大量的金属阳离子,它们对高分子聚合物阳离子官能团将产生静电排斥,使高分子链产生卷曲、甚至收缩为球形,由此大幅度减少了与纤维及填料的接触机会与空间,致使纸料中悬浮的细小组・74・陕西科技大学学报第27卷分粒子难以絮聚,阳离子聚合物的助留及助滤功能被削弱.2.2CPAM和MPAM用量对助留助滤性能的影响为了更好地比较CPAM与MPAM在电导率影响下的助留助滤效果,实验对聚合物助留剂的用量进行了研究,实验根据2.1节的结果,选择具有代表性的纸料电导率3084μs/cm和5140μs/cm作为研究条件,改变CPAM或MPAM用量,其它条件同上.图3和图4为纸料电导率在3084μs/cm时助留剂用量改变对纸料的助留及对纸料滤水性的影响.由图中看到,随着助留剂用量的增大,CPAM与MPAM,助留剂在用量超过0.02%后,MPAM对细小组分的助留性能略优于,这说明在低电.图3电导率为3084μs/cm时图4电导率为3084μs/cm时对细料留着的影响对纸料滤水性的影响图5和图6为纸料电导率在5140μs/cm时助留剂用量改变对纸料的助留及对纸料滤水性的影响.由图中相应的助留助滤关系曲线可以看到,由于电导率较高,纸料初始留着率及滤水性低于电导率为3084μs/cm时的初始值.随着助留剂用量的增大,MPAM与CPAM对纸料的助留助滤性能有一定的提高,但CPAM的助留助滤效果明显低于MPAM.从图中也能发现,即使CPAM的用量在0.05%时其助留与助滤效果也难以达到MPAM用量为0.02%的水平.在助留剂添加量为0.01%时,MPAM致使的纸料游离度为245mL和细料留着率为70.3%,CPAM致使的纸料游离度为210mL和细料留着率为68.2%;在助留剂添加量为0.05%时,MPAM致使的纸料游离度为290mL和细料留着率为74.4%,CPAM致使的纸料游离度为235mL和细料留着率为70.3%.图5电导率为5140μs/cm时图6电导率为5140μs/cm时对细料留着的影响对纸料滤水性的影响比较电导率3084μs/cm和5140μs/cm下CPAM与MPAM对纸料的助留助滤性能,可见,在低电导率情况下,高分子聚合物的相对分子质量与电荷密度同时对纸料的留着及滤水性能改善发挥着作用;而在较高电导率影响下,聚合物的电荷密度发挥出的作用要优于其相对分子质量.由于MPAM采用了高比例的DADMAC阳离子单体,显示出更大的电荷密度,因此大分子链受到来自电导率的影响小得多,线性大分子被挤压、卷曲的现象较轻,也比较舒展.综上所述,在相对低的电导率环境下相对分子质量高的CPAM对纸料的助留助滤效果好于MPAM,・84・第3期袁广翔等:抗盐性阳离子聚丙烯酰胺助留剂的应用探讨而在较高电导率情况下,高阳电荷密度的MPAM对纸料的助留助滤效果好于CPAM.2.3DCS对助留助滤性能的影响造纸纸浆构成绝干部分为化学浆及部分损纸,可能含有部分BCTMP或APMP以改善纸的物理及光学性能,也有可能为二次纤维等,上述原料中一般带有一定量的水溶木质素与半纤维素、阴离子淀粉、分散剂、脱墨化学品和涂布助剂等以及造纸过程伴随其它助剂所带入的分散剂等阴离子垃圾,由于造纸白水封闭循环将引起阴离子垃圾的积累,从而影响到阳离子功能助剂及助留系统功能的效能以及生产的正常运行.因为DCS带有大量的负电荷,,在阳离子高分子聚,,其阳电荷密度大大下降、甚至消失,.本论文选择了4:丁苯胶乳模拟涂布损纸回抄带入的涂料胶粘剂,,粉,,CPAM或MPAM构成助留系统对DCS的抗干扰性.实验所用的DCS1%,模拟物由丁苯胶乳、松香胶、氧化淀粉和碱木素组成,4种物质各占0.25%.研究仍选用Hydrocol助留系统,研究所准备的纸料含25%碳酸钙填料,DCS模拟物用量为1%,固定膨润土用量为0.2%,改变CPAM或MPAM的用量,测定纸料的留着和滤水性能,结果如图7和图8所示.图7DCS对助留剂助留性能的影响图8DCS对助留剂助滤性能的影响由图7和图8看到,在DCS的影响下,细料的初始留着率仅为56.9%,初始游离度为200mL,随着助留剂用量增加,细料助留率在提高,纸料滤水性也逐步得到改善.在MPAM添加量为0.02%时,细料的留着率为67.7%,纸料游离度为265mL;而同样添加量下的CPAM,细料的留着率仅为61.4%,纸料游离度为240mL.在助留剂用量0.05%时,MPAM对细料的留着率提高到74.1%,纸料游离度上升到295mL;而CPAM对细料的留着率仅为66.5%,纸料游离度为255mL.从上述研究数据可以发现,在MPAM用量0.02%时的助留助滤性能超过了CPAM用量为0.05%的水平,这说明MPAM的相对分子质量即使比CPAM低很多,但因其带有更多的阳离子基团,足以克服来自DCS的影响,并在纤维以及细小组分微粒表面形成阳离子补丁,最后阳离子补丁颗粒与膨润土构成微粒絮聚.相比较而言,CPAM由于较低的阳电荷密度,在大量的DCS干扰下只有提高其用量才能使助留系统发挥作用.3结论(1电导率对阳离子高分子聚合物的助留及助滤性能有影响.随着电导率升高,阳离子高分子聚合物的助留及助滤性能逐渐降低;在电导率3000μs/cm以下,阳离子聚合物的相对分子质量越大,其助留及助滤性能越好,即CPAM的助留及助滤性能优于MPAM;电导率在3000μs/cm以上,MPAM的助留及助滤性能开始优于CPAM,此时电荷密度主导对纸料的助留及助滤作用,而相对分子质量高低的影响成为次要因素.(2无机盐含量高低将引起系统电导率的变化.高阳电荷密度的MPAM在同样用量条件下有比CPAM更高的助留助滤效果,尤其是在较高电导率情况下.・94・陕西科技大学学报第27卷(3高阴离子垃圾含量将严重削弱阳离子高分子聚合物对纸料的助留助滤性能.由于MPAM带有更多的阳离子基团,在纤维以及细小组分微粒表面形成阳离子补丁,并能较好地克服来自DCS的影响,与膨润土构成微粒絮聚,从而表现出比CPAM体系更高的助留助滤效能.参考文献[1]DobbinsR.J.,AlexanderS.D.Thephysicalandopticalp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ddedtothisprepolymerat90℃understirringwithinseveralminutes,thenthemixturewaspouredintoametalmold,curedat110℃for24h,placedatambienttemperatureforoneweekbeforetest.2.3PreparationofPU/OMMTnanocompositesThestoichiometricmixtureofPTMGandOMMTwasheatedto60℃underrapidstirringfor24h.TheLMDIwith2.57molartimesofPTMGwasaddedtothemixtureofPTMGandOMMT,thenthenewmixturewasheatedto80℃for2htoformanisocyanateterminatedpolyurethaneprepolymerwithOMMTwhichwasvacuumdegassedat80℃untiltherewasnogasinit.ThestoichiometricBDOwasaddedtothisprepolymerat90℃underrapidstirringwithinseveralminutes,thenthemixturewaspouredintoametalmold,curedat110℃for24h,placedatambienttemperatureforoneweekbeforetest.2.4PreparationofPU/PMMA2IPNThemixtureofLMDIandPTMGatmolarratioof2.4∶1washeatedto80℃for2htoformanisocyanateterminatedpolyurethaneprepolymer.TheisocyanateterminatedpolyurethaneprepolymerwasevenlymixedwithBDO,MMA,EGDMA,BPOandN,N2dimethylaniline(DMAatstoichiometricweightratiosinareac2tionkettleatambienttemperature.Thenthelastmixturewasdegassedatvacuumforseveralminutes,pouredintoametalmold,reactedatambienttemperatureforabout10h,curedat110℃for24h,placedatambienttemperatureforoneweekbeforetest.2.5PreparationofPU/PMMA/OMMTnanocompositesThestoichiomtricPTMG,OMMTandMMAwereblendedbyultrasonicinstrumentatambienttempera2turefor30min.TheLMDIwith2.63molartimesofPTMGwasaddedtothemixtureofPTMG,OMMTandMMA,thenthenewmixturewasheatedto80℃for2htoformanisocyanateterminatedpolyurethaneprepoly2merwithOMMTaswellasMMA.ThestoichiometricMMA,BDO,EGDMA,BPOandDMAwereaddedtothisprepolymerinareactionkettle.Thewholemixturewasthoroughlyblendedatambienttemperaturequicklyandvacuumdegassedwithinseveralminutes,thenthemixturewaspouredintoametalmold,reactedatacer2taintemperatureforabout10handcuredat110℃for24handplacedatambienttemperatureforoneweekbe2foredetermination.2.6MeasurementTensilestrength,elongationatbreakandtensilemodulusweremeasuredaccordingtoGB/T52821998withUT22060electronicuniversaltestingmachineatambienttemperatureatacross-headspeedof(500±50mm/3Resultsanddiscussion3.1StructureandmorphologyofdifferentsystemsTherewerethreekindsofpolymer2layeredsilicatenanocomposites:intercalated,intercalated/exfoliatedandexfoliatednanocomposites[20].XRDwasaneffectivemethodfortheevaluationoftheintercalationcapabilityofpolymers.TheexpansionoflayersoforganoclaycanbedetectedbyXRD.Andtheinterlayerspacing(d2spacingvalueofclayscanbeobtainedfromtheircharacteristicdiffractionpeaksofthe(001plane,basedonBragg’sequation,whichmadetheintercalationcapabilityofpolymersnumerable.Inintercalatednanocompos2ites,thecharacteristicdiffractionpeakshiftedtowardlowerdiffractionangle.Inexfoliatednanocomposites,nocharacteristicdiffractionpeakcouldbeobtained.However,inintercalated/exfoliatednanocomposites,whetherthecharacteristicdiffractionpeakappearedornotitwoulddependontheexfoliateddegree.Fig1XRDpatternsofdifferentsys2temandOMMTThisresultsuggeststhattheintercalationcapabilityofPU/PMMA/OMMTbebetterthanthatofPU/OM2MT.BecausethemonomerofMMAandEGDMAasactivesolventdilutesthemixtureofPTMGandOMMT,whichmakesOMMTdispersedwellinthemixture.AnditmakesmorePTMGintercalatingintotheinterlayersofOMMTsothatthed2spacingvalueofOMMTbecomeslarger.WhenLMDIwasaddedtothesystemapor2tionofLMDIintercalatesintointerlayersofOMMTbecauseofthelargerd2spacingandthereactionbetweenLMDIandPTMGorOMMT.Thisincreasesd2spacingvalueofOMMTfurtherorevenmakestheparticlesofOMMTexfoliated.Therefore,thereisnoobviouslydiffractionpeakwithinsmallangleforPU/PMMA/OMMTbecaused2spacingvalueofOMMTisoutofthecapabilityofapparatus.Therefore,thecomprehensiveproper2tiesofthesystemcanbesharplyimproved,forexample,thethermalstabilityandmechanicalpropertieshavebothbeenimprovedasshowninfollowingparts.Additionally,they(PU,PU/OMMT,PU/PMMA2IPNandPU/PMMA/OMMTallpresentawidediffractionpeakwith2θrangefrom~10°to30°.Theresultssuggestthatthereareshort2haularrangementinsequenceofmolecularchainsinthesesystems[21].Furtherevidenceofnanometer2scaledispersionofMMTandphasestructureinthecaseofPU/PMMA/OMMTwillbesupportedbySEMimagesasshowninFig2.ThedispersionofMMTinpolymermatrixandthephasestructurewereinvestigatedbySEMimagesasshowedinFig2.ItcanbeseenfromFig2(aand(bthattherearenoobviousmicrophaseseperationbothinPUandinPU/OMMT,andthatOMMTinpolymermatrixisbrokenintothetactoidswithunevendistributioninsizeof40~700nmduetothehighviscosityinPU/OMMTsystem.ItcanbeseenfromFig2(cthatmanywhiteparticleswiththesizeof40~450nmaredispersedinpolyurethanematrix.PUphasewillbecontinuousphaseinPU/PMMA2IPNsystembecausetheformationspeedofPUisbiggerthanthatofPMMA.ThereforethosewhiteparticlesrepresentPMMAparticlesandthereisnoobviousmicrophaseseperationinPU/PMMA2IPNsystem.ItcanbeseenfromFig2(dthatrupturesurfacepresentswavily.ThisresultsuggeststhattherebemicrophaseseperationbetweenPUandPMMAphasesinPU/PMMA/OMMTsystem.Wavecrestrepre2sentsPUphase,mainlycontinuousphaseandtroughrepresentsPMMAphase.WhenOMMTisdispersedinPU/PMMA2IPNsystem,theorganicmodifiermakestheinterfaceenergydecreasingandthehygrogenbondingformsbetweenthepolargroupsofOMMTandhardsegmentsofPUorCOofPMMA.ThiswillleadtothesizeofhardsegmentsofPUorPMMAdomainphaseincreasing.Manywhiteparticleswiththesizeof20~80nmandholeswiththesizeof50~450nmaremostlydispersedintheinterfacebetweenPUandPMMApha2ses,fewinPUandPMMAphases.AsweknowntheseholesformwhenthemontmorillonitewaspulledoutfromthepolymermatrixbecausetherewasstronginteractionbetweenMMTandthepolymermatrix.Thedis2persionsofthewhiteparticlesandholesaresimilar,whichsuggeststhatthesewhiteparticlesrepresentMMT.TheOMMTinPU/PMMA/OMMTnanocompositeisdispersedwellintothepolymermatrixandbreaksintosmallertactoidswithevendistributioninsizecomparedtoPU/OMMTbecauseofthedilutionofMMAandEGDMA.Fig2SEMimagesofdifferentsystems3.2ThermalpropertiesofPU/PMMA/OMMTnanocompositeThethermalstabilityofPU/PMMA-IPN,PU/OMMTandPU/PMMA/OMMTsystemswasinvestiga2tedbyTGAandDTGshowninFig3andFig4,whichprovidedsomeimportantdatasuchastemperatureatweightlossof5%,thepeaktemperaturesofthefirstdegradedstage,thesecondstageandthethirdstagede2finedasTd,T1max,T2max,andT3max,respectively,asshowninTable1.Asreportedinpreviousstudy[8],theenhancementofthethermaldurabilityofpolyurethanebysilicateshasrarelybeendemonstrated.Intermsofthermalproperties,themodifierofMMToftenremainedintheiroriginalchemicalstructures(lowmolecularweightinthenanocomposites,andthereforeproducedanegativeeffectonthethermalresistanceofthenanocomposites.FromFig3,itcanbeseenthattheintroduceofOMMTtoPU/PMMA2IPNmakesthethermaldurabilityimprovedobviouslycomparedPU/PMMA2IPNtoPU/PMMA/OM2MTnanocom2posite.Fig3TGAcurvesofdifferentsystemsFig4DTGcurvesofdifferentsystemsTable1ImportantdataobtainedfromFig3and4Td(℃Td50%(℃T1max(℃T2max(℃T3max(℃Residueat550℃(%FromFig3and4,itcanbeseenthatPU/OMMTnanocompositedegradeswithprocedureinthreestages,asreportedinpreviousstudies[8,22],thefirststage(253~368℃isdominatedbythedegradationofthehardsegmentofPUandthemodifierofMMT(CAB,T1maxis350.4℃,thesecondstage(368~461℃correlateswellwiththedissociationofthesoftsegment,T2maxis410.8℃,fromXRDresultthethirdstage(461~491℃mayresultfromthedegradationoftheintercalatedmolecularchains,thecorrespondingweightlossis1.4%.Andtheresidueat550℃ofPU/OMMTis9.7%.FromFig3and4,itcanbeseenthatPU/PMMA2IPNsys2temdegradeswithprocedureintwostages,asreportedbyGradwell[23],thefirststage(241~370℃isdomina2tedbythedegradationofthehardsegment,T1maxis351.3℃,thesecondstage(370~463℃correlateswiththedissociationofthesoftsegmentandPMMAchains,T2maxis404.0℃.Andtheresidueat550℃ofPU/PMMA2IPNis5.7%.However,thedegradationofPU/PMMA/OMMTinvolvesinfivestages.FromSEMresultthatthereismicrophaseseperationbetweenPUandPMMAphasesinPU/PMMA/OMMTnanocomposite,thefirststage(276~374℃maybedominatedbythedegradationofthehardsegmentofPUinPUphaseandthemodi2fierofMMT(CAB,whichissimilartothefirststageofPU/OMMT,T1maxis351.8℃,alittlehigherthanthatofPU/OMMT,whichmayresultfromthetanglementbetweenalittlePMMAandPUinPUphase.Thesecondstage(374~383℃maycorrelatewiththedissociationofthehardsegmentofPUinPMMAphase,thedissociationtemperatureishigherthanthatinPUphasebecausethereisbiggercontentofPMMAinPMMAphasesoastomoretanglement.Thethirdstage(383~445℃correlateswiththedissociationofthesoftseg2mentofPUinPU/PMMA/OMMTandPMMAchainsonlyinPUphase,T3maxis418.2℃,whichissimilartothesecondstageofPU/PMMA2IPNbutthedegradationtemperaturerangebecomeswiderandthepeaktemper2atureofthisstageincreases14.2℃,theseresultsmayresultfromthetetheredOMMTservedasathermalbar2rierdelayingthemfromdegradationduringheated.Thefourthstage(445~471℃maycorrelatewiththedis2sociationofPMMAchainsinPMMAphase,T4maxisabout450.7℃,whichissimilartothetwostageofPMMAdegradation[24],thepeaktemperatureofthisstageincreases10.5℃becauseofthetanglementwithPU.Thefifthstage(471~533℃mayresultfromthedegradationoftheintercalatedmolecularchains,thecorrespond2ingweightlossis2.9%,thedegreeofintercalationis2.1timescomparedtothatofPU/OMMT.Andtheresi2dueat550℃ofPU/PMMA/OMMTis9.3%.ComparedtothatofPU/PMMA2IPN,thevalueincreases3.5%.OMMTmaycontributesome2.0%.TheresultsconfirmedtherebetanglementbetweenPUandPMMAagain.Therefore,wecanconcludethatintroduceofOMMTtoIPNmakesthethermalpropertiesdramaticallyimprovedandmakesthedegreeofmicrophaseseperationincreased.3.3ThemechanicalpropertiesofPU/PMMA/OMMTInthispaper,PU,PU/PMMA2IPN,PU/OMMTandPU/PMMA/OMMTsystemswerestudiedinordertoinvestigatetheeffectofOMMTonmechanicalpropertiesofPU/PMMA2IPN.ThemechanicalpropertiesofthesematerialswereshowninTable2.ItcanbeseenfromTable2that100%modulus,tensilestrength,tearstrength,permanentsetandshoreAhardnessincrease,whileelongationatbreakdecreaseswhenPUismodifiedbyOMMT.Theseresultsmaybeassociatedwiththereasonsshownasfollowing:inPU/OMMT,OMMTparticlesarebrokenintothetactoidswithunevendistributioninsizesof40～700nminPUmatrix(shownasSEMimagesinFig2;asstressfocuspoints,thesetactoidsmakeelongationatbreakdecrease,permanentsetandshoreAhardnessincrease.Addi2tionally,theOMMToftactoids’surfaceisintercalated(shownasXRDcurveinFig1andTGA,whichmakes100%modulus,tensilestrengthandtearstrengthofPUincrease.BythemethodofIPNs,itcanbeseenfromTable2that100%modulus,tensilestrengthandtearstrengthincrease,whichisattributedtotanglementbe2tweenPUandPMMA,butpermanentsetandshoreAhardnessincrease,andelongationatbreakdecreasessharplybecauseoftherigidityofPMMA.WhenPU/OMMTismodifiedbyIPNmethod,100%modulus,ten2silestrength,elongationatbreakandtearstrengthofPUincreasefrom10.46,18.45MPa,300%and43.26kN/mto16.06,30.65MPa,350%and78.91kN/m,andpermanentsetandshoreAhardnessdecreasefrom36%and78to20%and65,respectively.TheseresultsindicatethatthemechanicalpropertiesofPU/OMMTsystemhavebeendramaticlyimprovedbyIPNmethod.Thereasonsmaybeshownasfollows.OMMTdisper2seswellinPU/PMMA/OMMTsystem,whichisconfirmedbyXRDandSEM,andPTMGaswellasMMAcanintercalatemoreeasilyintotheinterlayersofOMMT,whichisconfirmedbyXRDandTGA.WhenLMDIisaddedtothesystemaportionofLMDIisintercalatedintointerlayersofOMMTbecausethelargerd2spacingandthereactionbetweenLMDIandintercalatedPTMGorOMMT,whichincreasesthed2spacingofOMMTfurtherorevenmakestheparticlesofOMMTexfoliated.WhenBPOisaddedinthesystem,intercalatingMMAwouldinsitupolymerizeininterlayersofOMMT,whichwillincreasethed2spacingofOMMTorevenmaketheparticlesofOMMTexfoliated.Therefore,themechanicalpropertiesofPU/OMMThavebeensharplyim2proved.4ConclusionsPU/PMMA/OMMTnanocompositewaspreparedbysynchronousintercalatedpolymerizationbasedonthenano-intercalatingtechniqueandtheIPNmethodtogether.PU/OMMTistheinterecalatednanocompositebe2causethed2spacingincreasesandtheOMMTisunevendispersedinpolyurethanematrixwiththetactoidsof40～700nm.PU/PMMA/OMMTistheinterecalatednanocompositebecausetheOMMTparticlesof20～80nmlengtharedispersedwellinpolymermatrixandtheintercalationdegreeis2.5timesrelatedtothatofPU/OM2MT.TheintroduceofOMMTintoPU/PMMA2IPNsystemmakestheplasticphasesizeincreaseandthemi2crophaseseperationmoreobviousbetweenPUandPMMAphases.TheresultsofTGAindicatethatthethermalstabilityofPU/PMMA/OMMTnanocomositebebetterthanthatofPU/PMMA2IPNandPU/OMMTnano2compositebecausethephasestructureandtheintercalationdegreeofOMMThavebeenimproved.Additional2ly,themechanicalpropertiesofPU/PMMA/OMMTnanocompositesaresuperiortothoseofothercomparativesystems.References:[1]WangZ,PinnavaiaT.[J].ChemMater,1998,10:376923771.[2]IanR,StevenB,NicholasEH,etal.[J].JournalofAppliedPolymerScience.2004,91:133521343.[3]KimJ,JungW,ParkW,etal.[J].JournalofAppliedPolymerScience,2003,89:313023136.FULi2hua,etal:Preparation,structureandpropertiesofpolyurethane/poly(methylmethacrylate/organo2montmorillonitenanocomposites1643Table2MechanicalpropertiesofdifferentsystemsPUPU/OMMT10.4618.4518.453003647.30783.897.6816.5