材料加工形态学7-1注塑-形态.ppt
注塑聚合物结构、形态李忠明（四川大学高分科学与工程学院,高分子材料工程国家重点实验室，成都 610065）Structure and Morphology in Injection Molded Polymers and their blendsZhong-Ming Li（College of Polymer Science and Engineering,State Key Laboratory of Polymer Materials Engineering,Sichuan University,610065,Chengdu,PR CHINA）,专题报告,加工Processing,定构Structuring,Tailoring the properties of Polymer Parts,Contents,Characteristics of polymer melts flowing during injection moldingMolecules conformation and aggregate state structure 分子的构象和凝聚态结构(单相聚合物)Molecular orientation分子取向Crystal morphology 晶体形态Size of crystalsPhase morphology 相形态(多相聚合物)Phase orientation Phase shape Phase dispersion/distributionSize of the dispersed phase particlesWeldline 熔接痕,Injection Molding-复杂的应力和温度场（complicated stress and temperature fields）-非等温nonisothermal-非均匀剪切应力non-uniform shear stress-非均匀剪切应力non-uniform shear rate,Characteristics of melt flow during injection mold 注塑成型流动的特点,Unsteady flow失稳流动,在高剪切速率(106s1)区域，熔体黏度虽然可以降到最小值(即极限黏度)，但大分子链会在极高的剪切速率作用下完全被拉直，继续变形就会呈现很大的弹性性质，导致流动无法保持稳定的层流，熔体陷入一种弹性紊乱状态，各点的流速会互相干扰，通常将此现象称为失稳流动。,Shear stress limit and shear rate limit 极限剪切应力和极限剪切速率引起失稳流动的切应力和剪切速率分别称为极限切应力和极限剪切速率。,实验证明，大多数聚合物的Rre=48，如聚乙烯为6469、聚苯乙烯为7177、聚甲基丙烯酸甲酯为72。,判断聚合物熔体是否出现弹性紊乱或失稳流动的参数：,熔体破碎 melt fracture,浇口截面高度与模腔深度相差很大浇口截面高度与模腔深度相差不太大浇口截面高度与模腔深度接近低速充模的熔体很有可能突然转变为高速,Gate and cavity effect on melt flow during mold filling浇口和模腔对熔体充模流动的影响,Characteristics of extensional flow 扩展流动充模的特点,Injection molding induced structure and morphology注塑诱导形态,Structure and morphology of injection molded Polymer parts,skin core structure,Molecules conformation and aggregate state structure Nano scale纳米级 Molecule chain scale 分子链尺度Molecular orientation分子取向Crystal morphology 晶体形态Size of crystalsPhase morphology 相形态(多相聚合物)Micron/sub-micron scale微米、亚微米级（介观）Molecule chain bundle scale无数个分子链的聚集体Phase orientation Phase shape Phase dispersion/distributionSize of the dispersed phase particlesWeldline 熔接痕,Aspects of structure and morphology,分子取向构象,分子取向分子取向的优缺点注塑时分子取向的成因 剪切流动 拉伸流动,Shear,Elongational,Molecular orientation in mold filling,Influences of injection parameters on molecule orientation1模温；2制件厚度；3注射压力；4充模和保压时间；5料筒温度,Influences of mold and injection parameters on molecule orientation 模具和注塑条件对分子取向的影响,Shear stress distribution in a mold,The orientation degree of different positions across the thickness direction of the part,Skin-core structure,Skin,intermediate,core,Influences of molecule orientation on properties,Internal stress,Warp 翘曲,分子取向结晶,Shish-kebab,
