Preparation of multi-walled carbon nanotubes@graphene/thermoplastic vulcanizate composites and study on its thermoelectric properties
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摘要: 利用一维和二维两种填料(多壁碳纳米管(MWCNTs)@石墨烯(GE))的协同作用来改善热塑性动态硫化橡胶(TPV)的热电性能(导电和导热性能)和力学性能。本文通过熔融接枝共混法制备MWCNTs@GE/聚丙烯熔融接枝马来酸酐(PP-MA)母粒,在表征MWCNTs@GE/PP-MA母粒的结构、结晶性和微观形貌的基础上,进一步采用动态硫化方法制备具有独特网络结构的MWCNTs@GE/TPV复合材料,研究了MWCNTs@GE用量对MWCNTs@GE/TPV复合材料的相态结构、导电性能、导热性能及力学性能的影响。研究结果表明,与单组分填料制备的复合母粒相比,MWCNTs@GE并用体系具有协同作用,在PP-MA中分散均匀,与基体结合力强,在结晶过程中作为成核剂能够促进基体结晶,提高基体的结晶峰温度(Tc)和结晶度(Xc),减小结晶尺寸(LCrystallite)。MWCNTs@GE/TPV复合材料呈现出明显的“海岛”相结构,交联的丁基橡胶 (IIR)相以微米级颗粒状分散在PP-MA相中。MWCNTs和GE均匀分散在连续相PP-MA中,MWCNTs和GE间距离小于1 µm,形成MWCNTs@GE网络结构。当MWCNTs@GE/TPV复合材料中MWCNTs@GE含量达到3wt%时,交流电导率、导热率、断裂伸长率和拉伸强度达到最佳值。
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关键词:
- 多壁碳纳米管(MWCNTs) /
- 石墨烯(GE) /
- 热塑性动态硫化橡胶(TPV) /
- 复合材料 /
- 动态硫化
Abstract: We mainly used the synergistic effect of one- and two-dimensional fillers (multi-walled carbon nanotubes (MWCNTs)@graphene (GE)) to improve the thermoelectric and mechanical properties of thermoplastic vulcanizate (TPV). MWCNTs@GE/PP-MA masterbatch were first prepared by melt-graft blending. The structure, crystallinity and microstructure of MWCNTs@GE/PP-MA masterbatch were characterized. Then MWCNTs@GE/TPV composites with unique network structure were prepared by dynamic vulcanization method. The effects of the amount of MWCNTs@GE on the phase structure, electrical conductivity, thermal conductivity and mechanical properties of MWCNTs@GE/TPV composites were studied. The results show that the combination of MWCNTs and GE has a synergistic effect and can be used as nucleating agent to improve Tc and Xc and reduce LCrystallite in the crystallization process, compared with the masterbatch prepared with single filler. In the MWCNTs@GE/PP-MA masterbatch, MWCNTs and GE are uniformly dispersed in PP-MA and have strong bonding force with the matrix. The MWCNTs@GE/TPV composites show an obvious "island" structure, and the cross-linked IIR rubber is dispersed in the PP-MA phase as micron size particles. MWCNTs and GE are uniformly dispersed in the continuous phase PP-MA, and the distance between MWCNTs and GE is less than 1 µm, forming the MWCNTs@GE network structure. When the content of MWCNTs@GE in MWCNTs@GE/TPV composites reaches 3wt%, the alternating current (AC) electrical conductivity, thermal conductivity, elongation at break and tensile strength reach the best value. -
图 1 (a) 聚丙烯(PP)、PP熔融接枝马来酸酐(PP-MA)、多壁碳纳米管 (MWCNTs)/PP-MA母粒、石墨烯(GE)/PP-MA母粒和MWCNTs@GE/PP-MA母粒的FTIR图谱;(b) MWCNTs、GE、MWCNTs/PP-MA母粒、GE/PP-MA母粒和MWCNTs@GE/PP-MA母粒的Raman图谱
Figure 1. (a) FTIR spectra of PP, PP-MA, MWCNTs/PP-MA masterbatch, GE/PP-MA masterbatch and MWCNTs@GE/PP-MA masterbatch; (b) Raman spectra of MWCNTs, GE, MWCNTs/PP-MA masterbatch, GE/PP-MA masterbatch and MWCNTs@GE/PP-MA masterbatch
图 6 不同MWCNTs@GE含量MWCNTs@GE/TPV复合材料的热电性能:(a) 交流电导率随频率的变化;(b) 不同MWCNTs@GE含量MWCNTs@GE/TPV复合材料在102 Hz下的交流电导率;(c) 介电常数随频率的变化;(d) 导热系数
Figure 6. Thermoelectric properties of MWCNTs@GE/TPV composites with different MWCNTs@GE contents: (a) Alternating current (AC) conductivity vs frequency; (b) AC conductivity of MWCNTs@GE/TPV composites with different MWCNTs@GE contents at 102 Hz; (c) Dielectric permittivity vs frequency; (d) Thermal conductivity
图 7 不同MWCNTs@GE含量MWCNTs@GE/TPV复合材料的力学性能:(a) 应力-应变曲线;(b) MWCNTs@GE含量对MWCNTs@GE/TPV复合材料拉伸强度、断裂伸长率和弹性模量的影响
Figure 7. Mechanical properties of MWCNTs@GE/TPV composites with different MWCNTs@GE contents: (a) Stress-strain cures; (b) Effect of MWCNTs@GE content on tensile strength, elongation at break and elastic modulus of MWCNTs@GE/TPV composites
表 1 PP、PP-MA、MWCNTs/PP-MA母粒、GE/PP-MA母粒和MWCNTs@GE/PP-MA母粒的XRD数据
Table 1. XRD data of PP, PP-MA, MWCNTs/PP-MA masterbatch, GE/PP-MA masterbatch and MWCNTs@GE/PP-MA masterbatch
Sample LCrystallite/nm I110/I040 PP 26.5 0.64 PP-MA 25.2 0.60 MWCNTs/PP-MA 24.3 0.52 GE/PP-MA 23.2 0.48 MWCNTs@GE/PP-MA 21.6 0.38 Notes: LCrystallite—Crystal size of the PP crystal plane (040); I110/I040—Ratio of diffraction peak intensity of PP crystal plane (110) and crystal plane (040). 表 2 PP、PP-MA、MWCNTs/PP-MA母粒、GE/PP-MA母粒和MWCNTs@GE/PP-MA母粒的结晶数据
Table 2. Crystallization data of PP, PP-MA, MWCNTs/PP-MA masterbatch, GE/PP-MA masterbatch and MWCNTs@GE/PP-MA masterbatch
Sample Tc/℃ Tm/℃ △Hm/(J·g−1) Xc/% PP 100.2 142.7 93.6 44.8 PP-MA 102.8 141.2 99.5 48.3 MWCNTs/PP-MA 107.6 141.2 103.2 50.9 GE/PP-MA 106.2 141.1 107.6 53.1 MWCNTs@GE/PP-MA 109.3 140.8 115.3 56.9 Notes: Tc and Tm—Crystallization peak temperature and melting temperature; ΔHm—Enthalpy of PP; Xc—Crystallinity of PP. -
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