尼龙6基聚合物共混物拉伸行为和相容性研究

发布时间：2018-10-10 14:01

【摘要】：聚合物的相容性是决定共混材料相界面结构、形态、性质以及相关力学性能的关键因素。同理,聚合物共混物的某些力学行为,在一定程度上也反映了共混组分间的相容性。由于聚合物的拉伸性能测试是表征其力学性能最简单的方法。因此,利用聚合物共混物拉伸应力-应变曲线,探寻其行为与共混物相容性的关联关系,具有一定的理论与实际意义。本文利用反应型增容剂PP-g-MAH、EPDM-g-MAH、SMA、SAN-g-MAH,通过熔融共混的方法制备了一系列PA6基共混物。研究了共混物在不同温度下的拉伸应力-应变行为,发现共混物的拉伸行为与体系相容性存在一定的关联,并通过扫描电子显微镜(SEM)、转动态热分析仪(DMA)、转矩流变仪和Molau实验对共混物的相容性情况进行验证。首先研究了不同共混组成的PA6/PP共混物的拉伸应力-应变行为,发现随着分散相PP含量的增加,共混物的拉伸强度和断裂伸长率呈现规律性递减。通过DMA、SEM测试表明,PA6/PP共混物体系随着分散相PP含量的增加相容性逐渐变差。进一步对PA6/PP共混物拉伸过程中的成颈变形能量(Qd)进行定义、计算,发现对不同组成的PA6/PP共混物而言,其Qd值越大,共混物相容性越好。其次制备了PP-g-MAH、EPDM-g-MAH增容的PA6/PP(半晶性/结晶性)共混物,研究了共混体系在不同拉伸温度下的拉伸应力-应变行为,结果表明,添加了增容剂的共混物的拉伸强度和断裂伸长率显著升高,且用PP-g-MAH增容的共混物体系具有最大的拉伸强度和断裂伸长率。SEM、转矩流变仪、Molau实验也验证了反应性增容剂的添加有效地改善了PA6/PP共混物体系的相容性,增容剂PP-g-MAH相较于EPDM-g-MAH对体系的增容效果更好。通过成颈变形能计算表明在增容PA6/PP共混物体系中,Qd越大,其共混物的相容性越好。最后制备了SMA、SAN-g-MAH增容的PA6/ABS(半晶性/非晶性)共混物,通过控制拉伸测试温度研究了共混物体系的拉伸应力-应变行为,并讨论了不同增容剂对共混体系相容性的改善情况。不同温度下的共混物的拉伸行为表明,添加了增容剂共混物的拉伸强度和断裂伸长率显著升高,且用SMA增容的共混物体系具有最大的拉伸强度和断裂伸长率。SEM、转矩流变仪、Molau实验表明反应性增容剂的添加有效的改善了PA6/ABS共混物体系的相容性,增容剂SMA相较于SAN-g-MAH对体系的增容效果更好。通过成颈变形能计算表明在增容PA6/ABS共混物体系中,Qd越大,其共混物的相容性越好。
[Abstract]:The compatibility of polymer is the key factor to determine the interfacial structure, morphology, properties and related mechanical properties of the blends. In the same way, some mechanical behaviors of polymer blends also reflect the compatibility of the blends to some extent. Because the tensile property of polymer is the simplest way to characterize its mechanical properties. Therefore, it is of theoretical and practical significance to explore the relationship between the behavior of polymer blends and the compatibility of the blends by using the tensile stress-strain curves of polymer blends. A series of PA6 based blends were prepared by melt blending with reactive compatibilizer PP-g-MAH,EPDM-g-MAH,SMA,SAN-g-MAH,. The tensile stress-strain behavior of the blends at different temperatures was studied. It was found that the tensile behavior of the blends was related to the compatibility of the blends. The compatibility of the blends was verified by scanning electron microscope (SEM) (SEM), dynamic thermal analyzer (DMA), torque rheometer and Molau experiment. The tensile stress-strain behavior of PA6/PP blends with different compositions was studied. It was found that the tensile strength and elongation at break of PA6/PP blends decreased regularly with the increase of PP content in dispersed phase. DMA,SEM test showed that the miscibility of PA6/PP blends became worse with the increase of PP content of dispersed phase. Furthermore, the necking deformation energy (Qd) during the stretching of PA6/PP blends was defined and calculated. It was found that the higher the Qd value of PA6/PP blends was, the better the compatibility of the blends was. Secondly, PA6/PP (semicrystalline / crystalline) blends with PP-g-MAH,EPDM-g-MAH compatibilization were prepared. The tensile stress-strain behavior of the blends at different tensile temperatures was studied. The tensile strength and elongation at break of the blends with compatibilizer increased significantly. SEM, torque rheometer and Molau experiment also proved that the addition of reactive compatibilizer can effectively improve the compatibility of PA6/PP blends. The compatibilizer PP-g-MAH has better compatibilization effect than EPDM-g-MAH. The necking deformation energy calculation shows that the greater the Qd, the better the compatibility of the blends in the compatibilized PA6/PP blends. Finally, PA6/ABS (semicrystalline / amorphous) blends with SMA,SAN-g-MAH compatibilization were prepared. The tensile stress-strain behavior of the blends was studied by controlling the tensile test temperature, and the improvement of the compatibility of the blends with different compatibilizers was discussed. The tensile behavior of the blends at different temperatures showed that the tensile strength and elongation at break of the blends with the addition of compatibilizer increased significantly. SEM, torque rheometer and Molau experiment show that the addition of reactive compatibilizer can effectively improve the compatibility of PA6/ABS blends. The compatibilizer SMA has better compatibilization effect than SAN-g-MAH. The necking deformation energy calculation shows that the greater the Qd, the better the compatibility of the blends in the compatibilized PA6/ABS blends.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631.21

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