十二烷基硫酸钠对多壁碳纳米管/聚对苯二甲酸乙二酯复合材料性能的影响

THE EFFECT OF SODIUM DODECYL SULFATE ON MULTI-WALLED CARBON NANOTUBE/POLY(ETHYLENE TEREPHTHALATE) COMPOSITES

用十二烷基硫酸钠(SDS)作为一种改性剂处理多壁碳纳米管(MWCNT),SDS处理后的MWCNT命名为SCNT,并采用微型挤出机和微型注塑机分别制备了MWCNT/PET和SCNT/PET复合材料.从材料的微观结构,导电性能,结晶性能和机械性能等角度,研究了SDS对MWCNT/PET复合材料性能的影响.结果表明,SDS处理能有效改善MWCNT在PET基体中的分散状态,促进导电网络的生成,可将复合材料电导率的逾渗值从2.35 wt%显著降低到0.18 wt%;在添加量为1 wt%的条件下,MWCNT对PET的导电性能没有影响,而SDS处理MWCNT可使PET的电导率从1×10-17 S/cm提高到6.5×10-8 S/cm;SDS对MWCNT的处理,不仅对提高PET的导电性能,而且较MWCNT对提高PET的机械性能有着更显著的作用效果.在添加量为1wt%时,SDS处理的MWCNT可使PET基体的拉伸强度提高31%,拉伸模量提高58%.

The multi-walled carbon nanotubes（MWCNT） were modified using sodium dodecyl sulfate（SDS） as the aid and the SDS treated MWCNT was named as SCNT.We successfully prepared the multi-walled carbon nanotubes/poly（ethylene terephthalate）（MWCNT/PET） composites and SCNT/PET composites with the desired filler content.The effects of the SDS on the MWCNT/PET composites were investigated from several aspects such as microstructure,electrical conductivity,crystallization behavior and mechanical properties.The results showed that SDS treatment can effectively improve the dispersion of MWCNT in the PET matrix,accelerate the construction of the electrical conducting networks.The percolation threshold of the composites can be dramatically decreased from 2.35 wt% to 0.18 wt%.At the 1 wt% filler content,MWCNT cannot increase the electrical conductivity of the PET composites,but SCNT induced a dramatic increase of about 10 orders of magnitude in the electrical conductivity of the PET composites.SCNT not only increased the electrical conductivity of the PET composites,but also more effectively improved the mechanical properties of the PET composites compared with MWCNT.At the 1 wt% SDS treated MWCNT content,SDS treated MWCNTs increase the tensile strength of PET matrix by about 31% and the tensile modulus of PET matrix by about 58%.Not like MWCNT/PET composites,SCNT/PET composites increase the tensile strength with increasing filler content after 1 wt% loading.Being similar to MWCNT,SCNT could act as a nucleating agent to shift the crystallization temperature of PET matrix to higher temperatures but decrease crystallinity of PET matrix with increasing filler content.The role of SDS in these MWCNT/PET composites has been explored in detail.