【作者】 梁勇；

【导师】 戴文利；

【作者基本信息】 湘潭大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 添加成核剂改性聚丙烯是实现聚丙烯高性能化的一个重要的方法,可以显著提高聚丙烯结晶性能以及机械性能等等。许多研究结果表明无机、有机以及不同结构的成核剂有显著的协同作用。为了充分发挥各种成核剂的优势,多组分复合是聚丙烯成核剂开发的重要趋势。本论文以低分子量PA6粉末为主体制备了NF系列复合成核剂。通过差示扫描量热仪、偏光显微镜、ARES高级流变仪等方法手段研究NF系列成核剂对聚丙烯/乙烯-辛烯共聚物弹性体共混体系结晶性能以及结晶形态的影响。采用Avrami方程以及LH理论对NF成核剂改性聚丙烯结晶动力学进行讨论。研究发现,NF系列成核剂对PP/POE共混体系都有一定的成核作用,对结晶速率、结晶温度、半峰宽、结晶度等都有不同程度的影响,其中NF-6,NF-9,NF-10三个复合成核剂综合效果最为出色。当成核剂含量从0%逐渐增加到0.6%的时候添加到PP/POE共混体系时候,聚丙烯共混体系结晶性能明显改善,并且趋势很明显,当用量超过0.6%的时候,结晶温度、速率等变化不明显。成核剂加入以后可以改善了PP/POE体系结晶性能。其中加入NF-14以后,结晶温度从PP/POE的117℃提高到131℃,提高了14℃,并且起始结晶温度也大幅度提高。加入NF-10以后共混体系结晶度约50%,结晶度是NF系列成核剂中最高的。而NF-9则是结晶速率最快的。结晶动力学研究结果说明,PP/POE和PP/POE/NF成核剂两个体系都同时存在均相成核和异相成核两种成核方式。加入成核剂以后半结晶时间t1/2明显减少和结晶速率G显著提高。成核剂加入之后对PP/POE的结晶形态产生了影响。PP/POE的球晶较大,各球晶生长相碰撞成明显的界面,NF系列成核剂的加入干涉了PP/POE完整球晶的形成,球晶界面变得模糊。使得晶体尺寸显著减小,晶核密度增大,结晶速率也加快。ARES高级流变仪扫描测试结果表明,加入NF系列成核剂以后使得PP/POE的储能模量、损耗模量、扭矩都增大。这说明成核剂加入以后改变了材料粘弹性比例,改变了材料性能。ARES高级流变仪扫描结果与动力学结果一致,说明加入NF系列成核剂以后共混体系结晶行为基本符合Avrami方程和LH理论。更多还原

【Abstract】 Modification of PP by adding nucleating agents is an important way to improve the performance of PP resin. It can significantly improve the properties of crystallization and mechanical properties. Many studies demonstrated that there is significant synergy effect about nucleating agents consisting of inorganic, organic or other different structure substance. In order to make use of the advantages of a variety of nucleating agent, development of multi-component composite nucleating agent is an important trend for the modification of PP.A series of NF composite nucleating agent was prepared based on low molecular weight PA6 powder in this paper. The effect of NF composite nucleating agent on the crystallization properties and morphology of polypropylene ethylene-octene copolymer blends was investigated by means of differential scanning calorimetry, polarizing optical microscope, ARES advanced rheometer etc. We discussed crystallization kinetics of the modification of PP using NF composite nucleating agent by Avrami equation and LH theory.The results show that NF series nucleating agent have certain nucleation effect on PP/POE blends, they have varying degrees of impact on the crystallization rate, crystallization temperature, half peak width and crystallinity. Three of the NF series nucleating agents (NF-6, NF-9, and NF-10) have remarkable improved integrated effect. The effect of the amount of nucleating agent on the crystallization behavior of PP/POE blends: when the amount of nucleating agent is gradually increased from 0% to 0.6%, the crystallization properties of polypropylene blends improved significantly and the trend is very clear, while the amount of nucleating agent is more than 0.6%, crystallization temperature and crystallization rate changed slightly.Adding nucleating agents into PP/POE blends improved the crystallization properties. After adding NF-14, the crystallization temperature of PP/POE blends increased from 117℃to 131℃, elevating 14℃, and the crystallization temperature of start crystal also increased significantly. Adding NF-10, the crystallinity of PP/POE blends was about 50%, which is the most effective nucleating agent on elevating the crystallinity within NF series nucleating agent. When adding NF-9, it can lead to the fastest crystallization rate.The results of crystallization kinetics show that all the two systems of PP/POE and PP/POE/NF exist homogeneous nucleation and heterogeneous nucleation simultaneity. The crystallization half-time t1/2 remarkably decreased and the crystallization rate G significantly enhanced after adding nucleating agent. Adding the nucleating agent had an impact on the crystallization morphology of PP/POE. The spherulites size of PP/POE is large, when spherulites grows they collides with each other and forms a clear interface. Adding the nucleating agent interfere the formation of complete crystal ball and the spherulites interface becomes blurred, it also reduces spherulites size significantly, increases nucleation density, improves the crystallization rate.ARES advanced rheometer scan results show that the storage modulus, loss modulus and torque of PP/POE are increased by adding NF series nucleating agent. While after adding NF-6 and NF-10, tan d is smaller than that of PP/POE. This shows that after the addition of nucleating agent the viscoelastic proportion of the material is changed, and change the material properties. ARES advanced rheometer scan results are consistent with the dynamics, which show that the crystallization behavior of blends is in accordance with Avrami equation and the LH theory after adding NF series nucleating agent.更多还原