学校代码：10385分类号：
研究生学号：1300507038密级：
鼓励自己的话语石墨烯与聚烯烃的复合方法及其对聚烯烃改性效果的研究Rearch on compounding methods of graphene and polyolefins and modification effect on polyolefins
作者姓名：于方波
指导教师：陈国华教授
学科：材料科学与工程
研究方向：复合材料世界顶级美景
所在学院：材料科学与工程学院辣炒萝卜丝
论文提交日期：二零一六年六月三日
关于春节的作文500字
摘要
仞岳摘要
信用卡营销话术
聚烯烃由于价廉、易加工成型和综合性能优良等特点，在生活与工业中广泛应用。然而聚烯烃在性能上仍存在一些不足，比如强度低、尺寸稳定性差及不能满足抗静电等功能性应用。为了改善聚烯烃的性能、拓宽其应用范围，需对其改性。石墨烯作为新型的二维碳材料，具有优异的力学、电学、热学等性能，将其用来改性聚烯烃具有较大的应用价值。
目前的研究主要是以改性石墨烯为填料通过溶液共混法对聚烯烃进行改性，存在诸多缺点，如改性过程繁琐、不环保及不适合大规模生产等。因此本论文以石墨烯与聚烯烃的复合方法作为切入点。本论文以机械剥离制备的少数层石墨烯为填料、高密度聚乙烯为聚烯烃基体，在熔融共混法的基础上，探究石墨烯与聚烯烃的复合方法及其对聚烯烃的改性效果。为了改善石墨烯在高密度聚乙烯基体中的分散均匀性及其二者间的界面结合，本论文采用三种复合方法（熔融共混法、改进熔融共混法和乙醇介质共混-熔融共混法）制备了高密度聚乙烯/石墨烯复合材料，研究了复合方法和石墨烯含量对复合材料的导电、力学等性能的改性效果。
本文分别将三种复合方法制备的粒状复合材料模压成型测试导电性能。随着石墨烯含量的增加，复合材料的电导率得到显著提高，表现出“渗流现象”。改进熔融共混法和乙醇介质共混-熔融共混法对复合
材料导电性能的改性效果一致，复合材料的渗流阈值均为4.82wt%（2.16vol%）；熔融共混法对复合材料导电性能的改善程度更大，复合材料的渗流阈值为3.75wt%（1.67vol%）。此外，还将改进熔融共混法和乙醇介质共混-熔融共混法制备的石墨烯包覆HDPE粉末模压成型测试导电性能。复合材料获得更优异的导电性能，其中改进熔融共混法制备的复合材料的渗流阈值为1.32wt%（0.58vol%），乙醇介质共混-熔融共混法制备的复合材料的渗流阈值为0.78wt%（0.34vol%）。
随后本文将三种复合方法制备的粒状复合材料注塑成型并进行力学性能测试。复合材料的拉伸性能和弯曲性能得到改善。其中乙醇介质共混-熔融共混法的改性效果最好，这归因于石墨烯较好的分散均匀性及石墨
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华侨大学硕士学位论文
烯与HDPE基体间较强的界面相互作用。复合材料的拉伸强度和拉伸弹性模量分别提高4.9%和28.2%，弯曲强度和弯曲模量分别提高16.4%和27.8%。但复合材料的韧性随石墨烯含量的增加逐渐下降，其中乙醇介质共混-熔融共混制备的复合材料韧性降幅最小。
关键词：聚烯烃改性石墨烯复合方法性能
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Abstract
Abstract
Polyolefins are widely ud in life and industry due to its low cost,easy processing and excellent allround properties.However,there are still some shortcomings in their some properties,such as low strength,poor dimensional stability and unsuited for anti-static applications.To improve performance and broaden application areas,polyolefins should be modified.Graphene is a new two-dimensional carbon nanomaterial with excellent mechanical, electrical and thermal properties,which has good application prospect in modification of polyolefins.
The prent rearch mainly focus on the modification of polyolefins by means of solution blending with modified graphene.But this technique has some drawbacks,for example,tedious modified process,environmentally unfriendly and unsuitable for large-scale production.So we attempt to take compounding methods as a cut-in point.This thesis focus on compounding methods and modification effect on polyolefins,using multi-layer graphene prepared by mechanical exfoliation and HDPE as raw materials.In order to enhance the dispersion uniformity of graphene in HDPE matrix an
d interface bonding between graphene and HDPE matrix,this thesis prepared HDPE/graphene composite by three compounding methods including melt blending,modified melt blending and ethanol media blending-melt blending. And then we studied modified effect of compounding methods and graphene content on properties of HDPE.
In this thesis,the conductive properties of composites prepared by three compounding methods were tested.The electrical conductivity of the composites was improved dramatically with the increa of graphene content, which showed the percolation phenomenon.Modified melt blending and ethanol media blending-melt blending obtained the same modified effect on the conductive properties of composites,and the percolation threshold of two老师作文600字
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