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上海工程技术大学毕业论文注塑成型过程中聚合物结晶机制及力学行为的研究1目录摘要.........................................................1ABSTRACT.....................................................20引言.......................................................41注射成型过程中聚合物的结晶机制.............................51.1剪切流动诱导的聚合物结晶形态及结晶机制...................51.2剪切流动诱导聚合物结晶形态及结晶机制的理论模型...........61.2.1分子模型...............................................61.2.2唯象模型...............................................81.3剪切致聚合物结晶形态的变化...............................91.3.1片晶...................................................91.3.2伸直链晶体............................................101.3.3串晶..................................................111.3.4球晶..................................................111.3.5柱晶..................................................121.4注射成型工艺对聚合物结晶机制的影响......................131.4.1熔融温度和熔融时间的影响..............................131.4.2冷却速度的影响........................................141.4.3剪切条件的影响........................................141.4.4注射压力的影响........................................152注射工艺参数对结晶度影响的实验研究........................152.1聚合物结晶过程的实验研究方法............................152.2X射线衍射法测聚合物结晶度的原理.........................172.3X射线衍射法测聚合物结晶度的实验过程.....................18上海工程技术大学毕业论文注塑成型过程中聚合物结晶机制及力学行为的研究22.3.1实验原料..............................................182.3.2实验仪器..............................................182.3.3实验模具..............................................212.3.4实验过程..............................................222.3.5实验数据与结果........................................232.3.6实验结论与分析........................................283结晶度对力学性能的影响....................................313.1结晶度对拉伸强度影响的实验研究..........................323.1.1实验原料..............................................323.1.2实验仪器..............................................333.1.3实验步骤..............................................343.1.4实验数据和结果........................................343.1.5实验结果分析..........................................374结论和展望................................................384.1结论....................................................384.2展望....................................................39参考文献....................................................40致谢........................................................46译文........................................................47原文说明....................................................75上海工程技术大学毕业论文注塑成型过程中聚合物结晶机制及力学行为的研究1摘要结晶是自然界中一种既普遍又有趣的现象，也是一个热历程。随着聚合物材料日益广泛被应用，聚合物的结晶机制和力学行为越来越受到人们的重视。本文研究了注射成型过程中剪切流动诱导的聚合物结晶机制及制品的力学行为。通过注射成型实验，制备了不同工艺条件下的聚丙烯试样。使用X射线衍射仪，获得了不同工艺参数下聚丙烯试样的结晶度，并揭示了工艺参数对聚合物结晶机制的影响规律：(1)在模具温度、注射速度恒定的条件下，结晶度随机筒温度的增加而减少，机筒温度越高，其结晶度减少的趋势越平缓；(2)在机筒温度、注射速度恒定的条件下，结晶度随模具温度的增加而减少，模具温度与机筒温度相差越小，其结晶度减少的趋势越剧烈；(3)在机筒温度、模具温度恒定的条件下，结晶度随注射速度的增加而增加，剪切速率越大，其结晶度增加的趋势越剧烈。通过拉伸实验，分析了不同结晶度下制品的力学行为，发现结晶度对制品力学行为有重要影响：结晶度高，分子链排列有序而紧密，分子间作用力强；结晶度增高，密度增大，表面光泽度提高，但透明度降低；随着结晶度的增大，制品的弹性模量、抗拉强度和屈服强度都升高；冲击强度随结晶度的提高而减小；结晶度增加有利于提高软化温度和热变形温度；结晶度提高会使体积变小，收缩率加大，从而产生较大的内应力而引起翘曲。关键词：聚合物，注射成型，结晶机制，力学行为，X射线衍射仪上海工程技术大学毕业论文注塑成型过程中聚合物结晶机制及力学行为的研究2ResearchonthecrystallizationmechanismandmechanicsbehaviorofpolymerintheprocessofinjectionmoldingABSTRACTCrystallizationisanuniversalandinterestingphenomenoninnature,butalsoisathermalprocess.Withthewidelyapplicationofpolymermaterials,Wepaymoreandmoreattentiononthecrystallizationmechanismandmechanicsbehaviorofpolymer.Thearticlemainlyresearchonthecrystallizationmechanismandmechanicsbehaviorofpolymerintheprocessofinjectionmolding.Thoughtheinjectionmoldingexperimental,wemadepolypropylenesamplesofdifferentprocessingconditions.ThenwegetthecrystallinityofpolypropylenesampleswhichunderdifferentprocessparametersbyX-ray.Wefindhowtheprocessparametersinfluenceonthecrystallizationmechanismofpolymer:(1)Intheconstantmouldtemperature,injectionspeedcondition,withthemeltingtemperatureincrease,thecrystallinitydecrease.Thehigherthemeltingtemperatureis,theslowertendencyofcrystallinitydecrease.(2)Intheconstantmeltingtemperature,injectionspeedcondition,withthemouldtemperatureincrease,thecrystallinitydecrease.Thesmallertemperaturebetweenmouldtemperatureandmeltingtemperatureis,theacutertendencyofcrystallinitydecrease.(3)Intheconstantmeltingtemperature,mouldtemperaturecondition,withtheinjectionspeedincrease,thecrystallinityincrease.Thefastertheinjectionspeedis,theacutertendencyofcrystallinityincrease.Throughthetensileexperiments,analyzethemechanicsbehaviorofpolypropylenesampleswhichunderdifferentcrystallinity.Wefindthathighcrystallinitypolypropylenesamples,whichhasarrangementandorderlymolecularchain,increasingdensityandglosssurface,butthetransparency上海工程技术大学毕业论文注塑成型过程中聚合物结晶机制及力学行为的研究3decrease.Alsowecanseewiththecrystallinityincrease,theyieldstrengthandtensilestrengthofpolypropylenesamplesincrease,buttheimpactstrengthdecrease.Thecrystallinityincreaseishelpfultoimprovethesofteningtemperatureandthermaldeformationtemperature.Thecrystallinityimprovemakesvolumeincreased,resultinginareductionofstressandwarpagecause.Keywords:polymer,injectionmolding,crystallizationme