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1、聚氨酯_聚甲基丙烯酸甲酯_有机蒙脱土纳米复合材料的制备_结构与性能_英文_（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）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 o
2、f Technology,Guangzhou510640,ChinaK ey w ords:polyurethane;montmorillonite;poly(methyl methacrylate;interpenetrating polymer netw orks;nanocompositeC LC number:TB33Document code:A Article ID:100129731(20051021638207 1IntroductionPinnavaia1and coworkers first reported t he superior polyuret hane/mont
3、 morillonite(PU/MM Tnanocom2 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 intercalation2,3,were
4、used to prepare PU/MM T nanocomposites.The nanocomposites often exhibit remarkable improvement s in mechanical46,t hermal7,8,t ransport9,10and barrier11properties 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 an
5、d 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 i
6、t is necessary to develop a novel and simple met hod to modify t he PU/MM T nanocomposites.Interpenet rating polymer networks(IPNswere 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 networks12,13,which had
7、at2 t racted attention of researchers because of t he synergism for p roperties1418.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
8、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 exam
9、ple,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 ho
10、d 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(EGDMA3Found ation item:Supported by Guangdong Provincial Natural Science Foundation for Group Project(39172 R eceived d ate:200520622
11、0Modif ied d ate:2005208223Corresponding 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 rocess
12、ing met hod.Additionally,polyuret hane based on liquid4,42dip henyl2 met hane diisocyanate(L MDIand 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
13、 inspected by XRD and SEM.The t hermal properties were investigated by T GA.Their mechanical p roperties were also st udied.2Experimental2.1R a w materials2.2Preparation of PUThe mixt ure of L MDI and P TM G at molar ratio of2.41was heated to80for2h to form an isocyanate terminated polyuret hane p r
14、epolymer which was vacuum degassed at80until t here was no gas in it.The stoi2 chiomet ric BDO was added to t his prepolymer at90under stirring wit hin several minutes,t hen t he mixt ure was poured into a metal mold,cured at110for24h,placed at ambient temperat ure for one week before test.2.3Prepar
15、ation of PU/OMMT nanocompositesThe stoichiomet ric mixt ure of P TM G and OMM T was heated to60under 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 to80for2h to form an isocyanate terminated polyuret ha
16、ne prepolymer wit h OMM T which was vacuum degassed at80until t here was no gas in it.The stoichiomet ric BDO was added to t his prepolymer at 90under rapid stirring wit hin several minutes,t hen t he mixt ure was poured into a metal mold,cured at110for24h,placed at ambient temperat ure for one week
17、 before test.2.4Preparation of PU/PMMA2IPNThe mixt ure of L MDI and P TM G at molar ratio of2.41was heated to80for2h 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(DMAat st
18、oichiomet 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 at110for24h,placed at ambient temperat ure for one week before test.2.5Preparation
19、 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 to80for2h to form an isocya
20、nate 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
21、mixt ure was poured into a metal mold,reacted at a cer2 tain temperat ure for about10h and cured at110for24h and placed at ambient temperat ure for one week be2 fore determination.2.6MeasurementTensile st rengt h,elongation at break and tensile modulus were measured according to G B/T52821998wit h U
22、 T22060elect ronic universal testing machine at ambient temperat ure at a cross-head speed of(50050mm/3R esults and discussion3.1Structure and morphology of different systemsThere were t hree kinds of polymer2layered silicate nanocomposites:intercalated,intercalated/exfoliated and exfoliated nanocom
23、po sites20.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 spacingvalue of clays can be obtained f rom t heir characteristic diffraction peaks of t he(001plane,ba
24、sed on Braggs 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 intercalat
25、ed/exfoliated nanocomposites,whet hert he characteristic diffraction peak appeared or not it would depend on t he exfoliated degree.Fig1XRD patterns of different sys2 tem and OMM TThis 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
26、 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
27、 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 h
28、in 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
29、part s.Additio nally,t hey(PU,PU/OMM T,PU/PMMA2IPN and PU/PMMA/OMM Tall p resent a wide diffraction peak wit h2range from10to30.The result s suggest t hat t here are short2haul arrangement in sequence of molecular chains in t hese systems21.Furt her evidence of nanometer2scale dispersion of MM T and
30、 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(aand(bt hat t here are no obvio us microp hase seperat
31、ion 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 of40700nm due to t he high viscosity in PU/OMM T system.It can be seen f rom Fig2(ct hat many white particles wit h t he size of40450nm are dispersed in polyuret hane ma
32、t 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(dt hat rupt ure
33、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 modi
34、fier 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
35、t he size of50450nm 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
36、 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 o
37、f t he dilution of MMA and EGDMA. Fig2SEM images of different systems3.2Therm 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 tem
38、perat 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 udy8,t he enhancement of t he t hermal durability of polyuret hane by silicates
39、 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 weightin 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 s
40、een 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(T3
41、max(Residue at550(%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 udies8,22,t he first stage(253368is 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 st
42、age(368461correlates well wit h t he dissociation of t he soft segment,T2max is410.8,f rom XRD result t he t hird stage(461491 may result f rom t he degradation of t he intercalated molecular chains,t he corresponding weight loss is1.4%. And t he residue at550of PU/OMM T is9.7%.Fro m Fig3and4,it can
43、 be seen t hat PU/PMMA2IPN sys2 tem degrades wit h p rocedure in two stages,as reported by Gradwell23,t he first stage(241370is domina2 ted by t he degradation of t he hard segment,T1max is351.3,t he second stage(370463correlates wit h t he dissociatio n of t he soft segment and PMMA chains,T2max is
44、404.0.And t he residue at550of 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(276374may be do minated by t he degradation of t he
45、 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(374383may correlate wit h t he diss
46、ociation 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(383445correlates wit h t he dissociation of t he soft seg2 ment of PU in PU/PMMA/OMM
47、 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
48、 delaying t hem fro m degradation during heated.The fourt h stage(445471may 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 n24,t he peak temperat ure of t his stage increases10.5because of t he tanglement w
49、it h PU.The fift h stage(471533may 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 at550of 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 c