Gaska Karolina, Kádár Roland, Rybak Andrzej, Siwek Artur, Gubanski Stanislaw
Department of Electrical Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden.
Department of Industrial and Materials Science, Chalmers University of Technology, 41296 Gothenburg, Sweden.
Polymers (Basel). 2017 Jul 21;9(7):294. doi: 10.3390/polym9070294.
This contribution reports on properties of low-density polyethylene-based composites filled with different amounts of graphene nanoplatelets. The studied samples were prepared in the form of films by means of the precoating technique and single screw melt-extrusion, which yields a highly ordered arrangement of graphene flakes and results in a strong anisotropy of composites morphology. The performed tests of gas permeability reveal a drastic decrease of this property with increasing filler content. A clear correlation is found between permeability and free volume fraction in the material, the latter evaluated by means of positron annihilation spectroscopy. A strong anisotropy of the thermal conductivity is also achieved and the thermal conductivity along the extrusion direction for samples filled with 7.5 wt % of GnP (graphene nanoplatelets) reached 2.2 W/m·K. At the same time, when measured through a plane, a slight decrease of thermal conductivity is found. The use of GnP filler leads also to improvements of mechanical properties. The increase of Young's modulus and tensile strength are reached as the composites become more brittle.
本论文报道了填充不同含量石墨烯纳米片的低密度聚乙烯基复合材料的性能。所研究的样品通过预涂覆技术和单螺杆熔融挤出制备成薄膜形式，这使得石墨烯薄片高度有序排列，并导致复合材料形态具有强烈的各向异性。进行的气体渗透性测试表明，随着填料含量的增加，该性能急剧下降。在渗透率与材料中的自由体积分数之间发现了明显的相关性，后者通过正电子湮没光谱法进行评估。还实现了热导率的强烈各向异性，对于填充7.5 wt%石墨烯纳米片（GnP）的样品，沿挤出方向的热导率达到2.2 W/m·K。同时，当通过平面测量时，发现热导率略有下降。使用GnP填料还能改善机械性能。随着复合材料变得更脆，杨氏模量和拉伸强度会增加。
