高分子的力学性能探析.ppt

Mechanical Properties of Polymers ;Mechanical Properties;9.1 Stress-Strain Behavior of Polymers;Stress-strain curve 应力-应变曲线;Typical stress-strain curve;Molecular motion during tensile test 拉伸过程中高分子链的运动;Types of stress-strain curve 应力-应变曲线的类型;True stress-strain curve 真应力-应变曲线;Considère drawing Considère作图法;Three types of true stress-strain curve 三种真应力-应变曲线 ;9.2 Yielding of Polymer;Cold drawing 冷拉;Principle of Yielding 屈服原理;韧性材料拉伸时，斜截面上的最大切应力首先增加到材料的剪切强度，因此材料屈服，并出现与拉伸方向成45?角的剪切滑移变形带。进一步拉伸时，剪切带中由于分子链高度取向强度提高，暂时不发生进一步的变形。而其边缘则进一步发生剪切变形。同样，在135?的斜截面上也发生剪切变形，因而试样逐渐生成对称的细颈，直至细颈扩展至整个试样 脆性试样在最大切应力达到剪切强度之前，横截面上的法向正应力已达到材料的拉伸强度，因此试样还来不及屈服就断裂了，而且断面与拉伸方向相垂直。;Shear band and Craze 剪切带和银纹;裂缝;Shear band and Craze 剪切带和银纹;9.3 Fracture Theory of Polymers;Griffith Fracture Theory Griffith断裂理论;Stress Concentration 应力集中;Griffith Equation Griffith方程;KI KIC 时破坏;Molecular Theory 断裂的分子理论;Activation energy of fracture 断裂活化能;Merry Christmas;9.4 Tensile Strength of Polymers;Theoretical strength 理论强度;Chain scission 断链;Chain slippage 分子间滑脱;Destroy of Van der Waals bond 范德华键破坏;Tensile Strength of Practical Polymers 实际高分子的拉伸强度;Tensile Properties of Polymers;Factor influencing Tensile Strength 影响高分子拉伸强度的因素;;;Orientation 取向;Defects 缺陷;;Temperature 温度;Brittle-ductile Transformation脆韧转变;Reinforcing of Polymers 高分子的增强;Fiber reinforcing 纤维增强;几种结构材料的力学性能;Short fiber reinforcing 短纤维增强;Particulates reinforcing 粒子增强;9.5 Toughness of Polymers;Impact Strength 冲击强度;Charpy Impact Strength 简支梁冲击强度;Izod Impact Strength 悬臂梁冲击强度;Factor influencing toughness 影响高分子韧性的因素;Temperature 温度;Deformation rate 应变速率;;;Orientation 取向;Defects 缺陷;Toughening of Polymers 高分子的增韧;Rubber toughening 橡胶增韧;聚苯乙烯的增韧;SEM micrograph of the fracture surface of PS/EPDM/SBS blends;Mechanical properties of the PS/EPDM (85/n) binary blends ;Mechanical properties of the PS/EPDM/SBS (85/n/10) ternary blends;Mechanism of rubber toughening 橡胶增韧机理;M