利用纳米力学系统研究多相橡塑材料的微结构及力学性能

发布时间：2018-01-24 08:43

本文关键词： 聚合物基复合材料纳米压痕技术微结构粘弹性力学性能　出处：《扬州大学》2017年硕士论文　论文类型：学位论文

【摘要】：聚合物基复合材料由于具有比强度高、比模量大、耐疲劳、耐腐蚀等优良的物理化学特性以及多功能性、结构易设计、易加工等优点,被广泛应用于各个领域。为了满足各个领域对材料越来越高的性能和结构的要求,从微观上设计、表征材料的结构和性能显得尤为重要。纳米压痕技术是一种测试材料微尺度力学性能的实验方法,该方法通过记录压痕过程中的载荷和深度的变化关系获得材料局部力学性能,可以实现对复合材料微结构的表征。近年来虽然纳米压入技术在实验方法,实验原理及仪器分辨率等方面有了明显的提高,但是对于高分子聚合物材料,尤其是粘弹性材料的微区力学性能的测试与应用仍然存在很多问题。本文围绕纳米压痕技术在橡塑材料中的应用进行了相关研究。复合材料的整体力学性能与组成相及界面的力学性能密切相关,本文利用纳米压痕技术对纳米颗粒增强的塑料、颗粒增强橡胶复合材料和并用胶各组成相及其界面进行细观力学性能表征,通过绘制同力学性能相对应的三维形貌图来建立复合材料微结构同宏观性能之间的关系。另外粘弹性会影响纳米压痕力学性能的测试结果,本文通过改变压痕实验中的测试条件,从微尺度研究了材料的粘弹性。具体的研究工作如下:(1)采用准静态和动态压痕技术研究了羟基磷灰石/聚乳酸(HA/PLA)复合材料在微尺度的表面力学性能。通过改变保载时间、卸载时间讨论了粘弹性对样品准静态力学性能的影响;在动态模式下探究了材料的动态力学性能;通过蠕变行为和划痕测试研究了复合材料的尺寸稳定性。结果表明准静态模式下只有当蠕变不充分时,加载条件会影响模量和硬度的测试结果;动态模式下存储模量和硬度随着压入深度的增加而减小。HA/PLA复合物的微区硬度曲线显示在相同载荷下,局部压痕塑性变形较小,表明HA提高了 PLA的力学性能。(2)利用纳米压痕技术表征钛酸铜钙/硅橡胶(CCTO/PDMS)复合材料的微结构信息,主要工作集中在利用超低载荷的压痕条件绘制同力学性能相对应的三维相貌图,从而反映微结构同宏观性能之间的关系,并分析不同粒径的CCTO对基体增强效果产生差异的原因。通过比较不同载荷绘制得到的模量图,得出5μN为最佳载荷。通过比较不同颗粒周围微区的模量变化曲线发现CCTO粒径小于1μm时,随着粒径的减小,基体微区模量增大,界面过渡区范围扩大,表现出模量均化现象,但粒径降低为300nm时,微区模量不再增加,表明颗粒增强效果与颗粒粒径有关。(3)利用纳米压痕技术对胶粉并用胶进行准静态和动态纳米压痕实验,通过改变准静态实验中的加载、保载、卸载时间,研究了时间速率对准静态力学性能的影响;在动态模式下探究了测试频率,动态载荷对动态力学性能的影响。综合考虑实验结果采用加载和卸载时间5s,保载20s作为准静态模式下的理想测试条件。动态压痕实验结果表明存储模量依赖于载荷的频率,胶粉含量越多,对测试频率的依赖性越明显;损耗因子随着频率的增加先增大后减小;相同频率下动态力越大,损耗角越大。通过测试不同胶粉含量的并用胶的微区力学性能发现随着胶粉含量的增加,微区内部胶粉分布密集,由于硫化不均形成的具有交联梯度的界面越多,材料在宏观力学性能上表现为拉伸强度随着胶粉含量的增多单调递减。
[Abstract]:Polymer composites due to their high specific strength, high specific modulus, fatigue resistance, corrosion resistance and other excellent physical and chemical properties and functional structure, easy to design, easy processing and other advantages, is widely used in various fields. In order to meet the performance and structure of the various fields of higher material and design requirements, from the micro structure, and material characterization is particularly important. The nano indentation technique is an experimental method to test the mechanical properties of micro scale materials, the method of obtaining local mechanical properties of materials through the relationship between the changes of load and indentation depth recording process, can realize the characterization of microstructure of composite materials. In recent years, although the nanoindentation the technology in the aspects of experimental methods, experimental principle and instrument resolution has been significantly improved, but for polymer materials, especially the micro mechanics of viscoelastic materials The test and application can still exist many problems. This paper focuses on the application of nano indentation technology in rubber materials in composite materials was studied. The mechanical properties and phase composition and is closely related to the mechanical properties of the interface, the enhancement of the nano particle by using the nano indentation technique of plastic particle reinforced rubber composites and blends each constituent phase and interface micromechanical characterization, to establish the relationship between micro structure and macro properties of composite materials by 3D drawing with the mechanical properties of the corresponding test results. Also will affect the viscoelastic properties of nano indentation, by changing the test conditions in indentation test, from the micro scale study the viscoelastic material. The specific studies are as follows: (1) the study of hydroxyapatite / poly lactic acid dynamic and quasi-static indentation technique (HA/PLA) composite The surface mechanical properties of materials in micro scale. By changing the holding time, the unloading time discusses the influence of viscoelastic quasi static mechanical properties of the samples; in the dynamic mode of dynamic mechanical properties of materials; the creep behavior and scratch test on the dimensional stability of the composites. The results show that the quasi static mode only when creep is not sufficient, the loading conditions will affect the test results of modulus and hardness; micro hardness curve of storage modulus and hardness under dynamic mode with increasing indentation depth and the decrease of the.HA/PLA complexes show under the same load, the local indentation plastic deformation is small, show that the HA can improve the mechanical properties of PLA (2). Using nanoindentation characterization of calcium copper titanate / silicone rubber (CCTO/PDMS) microstructure information of composite materials, mainly concentrated in the work of drawing Tongli indentation conditions by using ultra low load performance The corresponding three-dimensional appearance map, which reflects the relationship between micro structure and macro property, and analysis of different size CCTO the reasons for the differences of the matrix enhancement effect. By comparing the different load modulus by drawing, the 5 N is the best load. By comparing the different modulus curves of particles around the micro area CCTO found that the diameter of less than 1 m, with the decrease of particle size, matrix micro area modulus increase, transition zone of interface expansion, showing modulus phenomenon, but the particle size is reduced to 300nm, micro area modulus is not increased, indicating that the particles and enhancement effect of particle size of powder (3). And with a rubber quasi-static and dynamic nanoindentation experiments using nanoindentation technique, by changing the quasi-static experiments of loading, loading, unloading time, effect of time rate on static mechanical properties; in the dynamic mode of measurement Test frequency, dynamic load influence on dynamic mechanical properties. Considering the experimental results by loading and unloading time 5S, holding 20s as an ideal test conditions in quasi-static mode. Dynamic indentation experimental results show that the storage modulus depends on the load frequency, powder content more, the test frequency dependence is more obvious; loss factor with the increase of frequency increases first and then decreases; the same frequency under the dynamic force the greater the loss angle is greater. By testing different rubber content and mechanical properties of micro zones with glue with increasing rubber content, the micro area of powder distribution intensive, due to uneven sulfide formation interface more with cross-linked gradient. The material in the mechanical properties as tensile strength with the rubber content increased monotonically decreasing.

【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB324

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