简介:Inordertoimprovethemechanicalpropertiesofpolypyrrole,compositesweremadebyelectropolymerizingpolypyrroleinapolyurethanematrix.Polypyrrole/polyurethane(PPY/PU)compositefilmscontainingCLO4-,BF4-orCH3-C6H4-SO3-counterionsweremadeinavarietyofsolventsystemsandcharacterizedbySEM,electronicconductivity,FTIR,andmechanicalproperties.Compositefilmsshowingmuchgreaterfiexibilitythanpurepolypyrrolewereobtained,buttheirelectronicconductivitiesweresubstantiallylower.Measuredeonductivitiesrangedfrom0.001to8S/cm,tensilestrengthsfrom44to592psi,andelongationtofailurefrom3to70%.
简介:PP/claycompositeswithdifferentdispersions,namely,exfoliateddispersion,intercalateddispersionandagglomeratesandpanicle-likedispersion,werepreparedbydirectmeltintercalationorcompounding.TheeffectofclaydispersiononthecrystallizationandmorphologyofPPwasinvestigatedviaPLM,SAXSandDSC.Experimentalresultsshowthatexfoliatedclaylayersaremuchmoreefficientthanintercalatedclayandagglomeratesofclayinservingasnucleationagentduetothenano-scaledispersionofclay,resultinginadramaticdecreaseincrystalsize(lamellarthicknessandspherulites)andanincreaseofcrystallizationtemperatureandcrystallizationrate.Ontheotherhand,adecreaseofmeltingtemperatureandcrystallinitywasalsoobservedinPP/claycompositeswithexfoliateddispersion,duetothestronginteractionbetweenPPandclay.Comparedwithexfoliatedclaylayers,theintercalatedclaylayershavealessimportanteffectonthecrystallizationandcrystalmorphology.Noeffectisseenforsampleswithagglomeratesandpanicle-likedispersion,inregardtomeltingtemperature,crystallizationtemperature,crystalthicknessandcrystallinity.
简介:AnewtypeofSiO_2-MgO-CaO(SMC)whiskerwasusedtomodifyhighdensitypolyethylene(HDPE).Themeltingbehaviorandcrystallinitywereinvestigatedbydifferentialscanningcalorimetry(DSC).ThedispersionofwhiskersandinterfacialadhesioninthepreparedHDPE/SMCwhiskercompositeswereinvestigatedbyscanningelectronmicroscopy(SEM).Themechanicalpropertieswereevaluatedbymechanicaltestsanddynamicmechanicalanalysis(DMA).DSCdataindicatedthatthemeltingtemperatureandthecrystall...
简介:Thisstudyinvestigatedtheinfluenceofvariousorganicallymodifiedmontmorillonites(organoclays)onthestructureandpropertiesofrigidpolyurethanefoam(RPUF)nanocomposites.Theorganoclaysweremodifiedwithcetyltrimethylammoniumbromide(CTAB),methyltallowbis(2-hydroxyethyl)quaternaryammoniumchloride(MT2ETOH)andtris(hydroxymethyl)aminomethane(THMA)anddenotedasCMMT,Cloisite30BandOMMT,respectively.MT2ETOHandTHMAcontainhydroxylgroups,whileTHMAdoesnothavelongaliphatictailinitsmolecule.X-raydiffractionandtransmissionelectronmicroscopyshowthatOMMTandCloisite30BcanbepartiallyexfoliatedintheRPUFnanocompositesbecausetheirintercalatingagentsMT2ETOHandTHMAcanreactwithisocyanate.However,CMMTmodifiedwithnonreactiveCTABismainlyintercalatedintheRPUFmatrices.Atarelativelylowfillercontent,theRPUF/CMMTcompositefoamhasahigherspecificcompressivestrength(theratioofcompressivestrengthagainsttheapparentdensityofthefoams),whileatrelativelyhighfillercontents,RPUF/Cloisite30BandRPUF/OMMTcompositeshavehigherspecificcompressivestrengths,highermodulusandmoreuniformporesizethantheRPUF/CMMTcomposite.
简介:聚苯乙烯(PS)/triphenyl磷酸盐(TPP)composites被暂停聚合准备并且融化挤出,和火焰retardance和机械性质的比较研究被执行。结果比为获得PS/TPP的好dispersity融化挤出证明暂停聚合是一种更好的技术合成。TPPnanoparticles,是在尺寸的约50nm,被暂停聚合同质地并且一致地在一步舞在PS矩阵驱散。然而,PS/TPP合成部分被聚结,不规则地展出塑造了微米规模粒子由于融化挤出。与melt挤出相对照,由从21.8%增加到22.6%的暂停聚合的PS/TPPnanocomposite的有限的氧索引(LOI),和点火(TTI)的时间增加了12.3%,山峰热版本率(PHRR)在8.5%减少了,并且全部的热版本(THR)在11.0%减少了。由暂停聚合的PS/TPPnanocomposite的机械性质也增加了。张力的力量,在裂缝的延伸,和曲折力量分别地增加了36.4%,8.5%,和108%。
简介:在这个工作,flame-retardant聚丙烯(PP)/ramie纤维(RF)合成被准备。苎麻纤维被生产经由的包含磷、包含氮的火焰retardant(FR)化学上包在situ冷凝作用反应以便压制他们的烛蕊效果。红外线的光谱学(FTIR),X光检查光电子光谱学(XPS)和扫描电子显微镜学(SEM)表明了的Fourier变换苎麻纤维由FR(FR-RF)化学上包了,这成功地被获得。Thermogravimatric测试证明PP/FR-RF合成比PP/RF在高温度有更多的残余和更好热的稳定性合成。锥热量计(CC)结果显示热版本率(PHRR)和全部的热版本(THR)的山峰相应地与整洁的PP/RF的价值相比在23.4%和12.5%减少了。PP/FR-RF合成在燃烧以后创造了连续、紧缩的字符层。在有热传导系数的CC测试以后的字符残余的联合FTIR分析结果,RF上的FR的charring极大地削弱了RF的烛蕊效果,这能被结束,并且在RF域的更多的字符残余在整个燃烧地区便于更多的连续、紧缩的字符层的形成,因而在燃烧期间保护了PPcomposites,导致比PP/RF的合成的PP/FR-RF的更好的火焰retardancy合成。