資源描述：
《塑料的內(nèi)應(yīng)力控制改性（Internalstresscontrolofplastics）》由會員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在工程資料-天天文庫。
1、塑料的內(nèi)應(yīng)力控制改性(Internalstresscontrolofplastics)InternalstresscontrolofplasticsInternalstressofplasticsreferstoaninherentstressproducedbytheprocessofmeltingofplasticsduetotheorientationofmacromoleculechainsandcoolingandshrinkage?Theesseneeofinternalstressisnotbalaneed
2、conformationofmolecularchainformedinthemeltingprocess,theimbalanceintheconformationofcuringnotimmediatelycoolingreturntotheequilibriumconfonnationandadapttoenvironmentalconditions,theimbalanceofhighelasticdeformationoftheconfonnationisakindofreversible,highelasti
3、cdeformationandtheusualtofreezeenergystoredinplasticproducts,undersuitableconditions,theforcedunstableconformationwilltransformtotheconfonnationalfreedomofthestabilityofthepotentialenergyintokineticenergyrelease?Whentheforcebetweenthemacromolecularchainsandthefor
4、cesofentanglementcannotwithstandthiskineticenergy,theinternalstressbalanceisdestroyed,andtheplasticproductswillcausestresscrackingandwarpage?Almostallplasticproductswi11havevaryingdegreesofinternalstress,especiallyplasticinjectionproductsaremoreobviousstress?Thee
5、xisteneeofinternalstressnotonlycauseswarpageandcrackingofplasticproductsduringstorageanduse,butalsoaffectsthemechanicalproperties,opticalproperties,electricalpropertiesandappearancequalityofplasticproducts?Forthisreason,wemustfindouttheinternalstressesandtoelimin
6、ateinternalstressandreducethestressinsidetheplasticproducts,andtheresidualstressintheplasticproductsaredistributedasevenlyaspossible,toavoidthephenomenonofstressconcentration,therebyimprovingtheplasticmechanicalthermalproperties1.CausesofinternalstressinplasticsT
7、herearemanyreasonsfortheinternalstress,suchasplasticmeltbystrongershearinthemachiningprocess,orientationandcrystallizationprocessinthepresenceofmelt,allpartsofthecoolingspeedisextremelydifficulttoachieveuniformandnonuniformplasticization,demolding,whichwillleadto
8、internalstress?Accordingtothecausesofinternalstress,stresscanbedividedintothefollowingcategories?(1)orientationinternalstress;Theorientationinternalstressisaki
