2013届硕士毕业生
发布人： 发布时间: 2014-02-27 作者: admin 访问次数: 111

 

论文题目：不同熔融共混PEN增韧体系的增韧效果及其机理研究
毕业学生：毕丽颖
指导老师：吴唯教授
中文摘要：
        本文系统的研究了EPDM-g-MAH、TPEE以及 Surlyn®9320三种增韧剂对PEN增韧改性材料的制备以及增韧效果与增韧机理。实验通过增韧体系的冲击测试以及拉伸试验、弯曲试验和硬度的测试，研究了各增韧体系的增韧效果以及机理分析，采用差示扫描量热仪（DSC）、热变形维卡软化点测试仪、热重分析仪（TGA）等方法，分析了采用EPDM-g-MAH、TPEE以及 Surlyn®9320三种增韧剂增韧对体系热性能以及热稳定性能的影响。
通过对三种不同增韧剂的增韧效果的研究比较发现，EPDM-g-MAH作为增韧剂能够显著提高体系的冲击强度和断裂伸长率，但会显著降低增韧体系的强度及模量等其他力学性能。TPEE作为增韧剂，添加量不超过10wt%时，体系的强度以及模量不会大幅度降低，而冲击强度并没有得到显著的提高，TPEE的添加量进一步增加，体系的冲击强度会大幅度提高，此时的强度以及模量却显著下降。选择Surlyn®9320为增韧剂时，少量Surlyn®9320的添加，就能显著提高体系的冲击韧性以及断裂伸长率，同时体系的拉伸强度略微提高，弯曲强度以及模量仅稍有降低。而三种增韧剂的加入，都会使增韧后体系的耐热变形性以及热降解稳定性有所降低。
综合考虑三种增韧剂的增韧效果，Surlyn®9320选作增韧剂效果最优，而且添加量少，EPDM-g-MAH适合于对强度要求不高但对冲击韧性要求很高的体系，而TPEE则可以作为对冲击韧性没有很高要求，而要求不会显著降低材料强度以及模量的增韧体系。
Abstract ：
This paper systematically studies the PEN’s performance influenced by three different kinds of tougheners, EPDM-g-MAH, TPEE and Surlyn®9320. The impact test, tensile test and bending test methods were used to analyze the toughening effect and mechanism of these toughness systems. Differential scanning calorimeter (DSC), vicat softening point tester, as well as thermal gravimetric analysis (TGA) were used to characterize the melt crystallization properties, heat deformation properties and thermal degradation stability of these different toughness systems.
Comparison the toughening effects of three different tougheners, we found that EPDM-g-MAH as the toughener greatly improved the impact strength and elongation at break of the system, but significantly reduced the strength and modulus of the toughness system. When the content of TPEE was less than 10wt%, the strength and modulus of the blend were not dropped significantly, while the impact strength was not significantly improved. The content of TPEE was further increased, the impact strength of the system would be greatly improved, but the strength and modulus decreased significantly. When Surlyn®9320 as the toughener, the addition of a small amount of Surlyn®9320 could significantly improve the impact strength as well as elongation at break of the system, meanwhile the tensile strength was increased slightly, and only a slight decrease in the flexural strength and modulus. The addition of three different kinds of tougheners all decreased the system's thermal deformation resistance and thermal degradation stability.
Considering the toughening effect of three different tougheners, Surlyn®9320 has the best toughening effect with little addition, EPDM-g-MAH is suitable for the material which demands less for strength but high impact toughness. TPEE can be used in the system where the impact toughness is not very high requirements, while the strength and modulus should not be significantly reduced.
 
 
 
论文题目：PET-PEN熔融酯交换共聚酯对PET/PEN共混物的增容机理研究
毕业学生：王涛
指导老师：吴唯教授
中文摘要： 

       本文论述了用双螺杆挤出机和密炼机熔融共混，制备了PET/PEN共混材料，讨论了PET-PEN熔融酯交换共聚酯对PET/PEN共混材料的增容作用，研究了PET/PEN共混材料的性能及影响因素（共混时间、温度、螺杆转速及PEN含量等）及加入第三组分PET-PEN共聚物对PET/PEN共混材料的增容作用，并讨论了PET-PEN共聚物薄膜取代PET薄膜应用于薄膜电容器的可行性。结论表明，PET-PEN熔融酯交换共聚酯对PET/PEN共混物具有明显的增容作用。PET/PEN共混体系酯交换反应主要受共混时间决定，熔融共混25min后，PET/PEN(70:30 w/w)共混体系的无规度为0.60；随共混时间增加，共混物两相的Tg相互靠近，最终合并为一个Tg；随共混时间增加，分散相尺寸和粒径分布范围明显减小，两相的相容性得到明显改善；随共混时间增加，PET/PEN共混物的结晶性能、特性粘度降低。合理控制螺杆转速、共混温度及PEN含量，能获取理想的PET/PEN共混材料，其中，与纯PET相比，当PEN含量为30 wt%时，PET/PEN共混物的拉伸强度提高了16.1%，拉伸模量提高了13.9%；PEN含量为20 wt %的共混物维卡软化温度提高5.4℃。加入第三组分PET-PEN共聚物，使共混各组分的均匀分散性提高；能有效提高PET/PEN共混物的热稳定性，且PET-PEN共聚物用量越多，热稳定性提高越明显，当 PET-PEN 共聚酯用量为15质量份时，PET/PEN共混物起始失重温度提高了20.3℃；PET-PEN共聚物能提高PET/PEN共混物的维卡软化温度、拉伸和弯曲性能以及冲击韧性；当PET-PEN共聚物用量为5质量份时，增容改性综合效果最好。PET-PEN共聚物薄膜的介电常数在-80~80℃范围内稳定，介电稳定性优于PET薄膜；与纯PET薄膜相比，PET-PEN共聚物薄膜更适用于薄膜电容器。

Abstract ：

PET/PEN Blends were prepared via melt processing in a twin-screw extruder and a mixer torque rheometer. Compatibilizing effect of PET-PEN copolymers formed during melt transterification was discussed. The properties of PET/PEN Blends and influence of mixing time, screw rates, blending temperature and PEN content on the properties were studied. Compatibilizing effect of PET-PEN copolymer added to the blends was also investigated. The feasibility of applying PET-PEN copolymer films to film capacitors to replace pure PET films was also studied. The results showed that PET-PEN copolymer has significant compatibilizing effect on PET/PEN blends. The transterification reaction is mainly determined by mixing time. With mixing time of 25min, the randomness of PET/PEN blends is 0.60. With the increase of mixing time, two glass transitions approach closer and merge gradually. Under longer processing time, a smaller domain size of the dispersed-phase particles is obtained and the miscibility of PET/PEN blends is improved. As the mixing time increases, the crystallization and intrinsic viscosity decrease. The properties of PET/PEN Blends can be optimized with appropriate screw rates, blending temperature and PEN content. Compared with PET, tensile strength and tensile modulus increase by 16.1% and 13.9% respectively when PEN content is 30 wt%; Vicat softening temperature increases by 5.4℃ when PEN content is 20 wt%. The results showed that PET-PEN added to PET/PEN blends can improve the thermal stability of the blends effectively. Higher PET-PEN copolymer content is, better thermal stability of PET/PEN blends is obtained. The starting temperature of weight loss increases by 20.3℃ when PET-PEN copolymer content is 15 phr. The Vicat softening temperature, tensile and bending properties, impact toughness of PET/PEN blends are improved by PET-PEN copolymer. The comprehensive properties of the blends are best when PET-PEN copolymer content is 5 phr. The dielectric constant of PET-PEN copolymer films is stable in the range from -80 to 80℃ and PET-PEN copolymer films have better dielectric stability. PET-PEN copolymer is a promising candidate to take the place of PET in film capacitor application.