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1、异戊橡胶硫化过程的有限元模拟摘要异戊橡胶大分子的化学结构与天然橡胶的相同,性能与天然橡胶的十分相近,是天然橡胶的最佳替代品。发展异戊橡胶可以缓解我国对国际天然橡胶市场的过分依赖。硫化对橡胶制品的性能有十分重要的影响。在硫化过程中,橡胶分子由线型结构向空间网状结构转化,橡胶也因此获得了更完善的物理机械性能和化学性能。本文将前人建立的适用于等温条件的天然橡胶硫化反应动力学方程近似用于异戊橡胶,采用二维有限元模型,在忽略了硫化反应热效应的前提下,数值模拟了异戊橡胶注射成型工艺的硫化过程,分析了硫化介质温度、促进剂(MBT)浓度
2、等参数对于硫化过程中异戊橡胶温度场和硫化转化率场以及正硫化时间的影响。模拟结果表明:促进剂硫黄硫化具有自催化反应的特征;提高硫化介质温度可以显著减小正硫化时间,但橡胶温度与硫化率的不均匀程度也因此增大;提高促进剂的浓度可以减小正硫化时间,而对制品最终硫化率的均匀程度影响不大。关键词:异戊橡胶,硫化,转化率,温度场,有限元模拟FiniteElementSimulationofVulcanizationProcessofcis-1,4-PolyisopreneRubber38AbstractSynthesizedcis-1,
3、4-polyisoprenerubber(IR)hasthesamemolecularstructurewithnaturalrubber(NR),besidesthepropertiesofIRaresimilarwiththoseofNR.Therefore,IRistheoptimumsubstitutetoNRanditispossibleforourcountrytoreducethedependenceontheinternationalNRmarketbydevelopingIR.Vulcanization
4、hasasignificanteffectonthepropertiesofvulcanizates.Inthecourseofvulcanization,networkstructuresareformedbycrosslinkingoflinearrubbermoleculesandmorevaluablephysicalandchemicalpropertiesareobtained.Inthispaper,akineticmodelproducedintheisothermalvulcanizationofNRi
5、susedforthevulcanizationofIRunderthenon-isothermalcondition,andthenumericalcomputationexpressionofdegreeofcureisestablished.ThenthesimulationofacceleratedsulfurvulcanizationofIR,withouttakingintoaccountofreactionheat,intheinjectionmoldingprocessiscarriedoutbyappl
6、yingatwo-dimensionalfiniteelementmodel.Theeffectsofparameters,suchastemperatureofcuringmedia,accelerator(MBT)level,etc.,ontheoptimumcuretimeandprofileoftemperatureanddegreeofcureareanalyzed.Theresultssupporttheautocatalyticcharacteristicofacceleratedsulfurvulcani
7、zationofrubber.Additionally,theresultsindicatethatincreasingtemperatureofcuremediawillgiverisetoaremarkablereductionofoptimumcuretime,buttheuniformnessofrubbertemperatureanddegreeofcuredecreasesaswell.Whentheconcentrationofacceleratorincreases,theoptimumcuretimed
8、ecreaseswithoutdamagingtheuniformnessofdegreeofcure.Thelargertherubberproductis,theworsetheuniformnessofdegreeofcurewillbe.Keywords:cis-1,4-Polyisoprenerubber,