PBT/氧化石墨烯纳米复合材料的制备及热处理

先用Hummer法合成氧化石墨烯(GO)，然后用熔融共混法制备了不同GO含量的聚对苯二甲酸丁二醇酯(PBT)纳米复合材料(PBT/GO)。随着GO含量的提高PBT/GO纳米复合材料的拉伸强度和冲击强度都先提高后降低，GO的含量为0.5%的材料性能最佳。将GO含量为0.5%的PBT/GO纳米复合材料在不同温度(150、180和200℃)热处理不同时间(30、60和90 min)，研究了热处理对其结构和性能的影响。结果表明，随着热处理温度的提高PBT/GO纳米复合材料的拉伸强度和冲击强度最高达63.2 MPa和11.6 kJ/m²，比热处理前分别提高了36.1%和59.3%。而随着热处理时间的延长其拉伸强度和冲击强度最高分别为62.3 MPa和11.0 kJ/m²，分别提高了34.2%和51.9%。DSC分析结果表明，提高热处理温度和延长热处理时间都能提高复合材料的结晶度，结晶度比热处理前最多分别提高了11.4%和8.6%，温度对结晶度的影响更甚。XRD测试结果表明，热处理并不改变复合材料的晶型结构，只影响其结晶度。导热性能测试结果表明，复合料的结晶度越高则导热性能越好。提高热处理温度，复合材料在50℃和100℃的热导率最高分别为0.49 W/(m·K)和0.42 W/(m·K)，比热处理前分别提高了24.1%和18.6%；延长热处理时间，复合材料在50℃和100℃的热导率最高分别为0.46 W/(m·K)和0.37 W/(m·K)，比热处理前分别提高了14.6%和5.9%，热处理温度对导热性能的影响更显著。

Preparation and Heat Treatment of Nanocomposites of PBT/Graphene Oxide

The graphene oxide (GO) was firstly synthesized by the Hummer method, and then the nanocomposites of PBT/GO with different GO contents were prepared by melt blending. The mechanical properties of the PBT/GO-nanocomposites were tested. Results show that the tensile strength and impact strength of the nanocomposites increased first and then decreased with the increase of GO content, however the PBT/GO-nanocomposite with 0.5% GO exhibits the best mechanical performance. The PBT/GO nanocomposite with 0.5% GO was selected for further heat-treatment at various temperatures (150^oC, 180^oC and 200^oC) for differnet times (30 min, 60 min and 90 min), then the effect of heat-treating on its structure and properties were investigated. With the increase of heat treatment temperature the tensile strength and impact strength could reach as high as 63.2 MPa and 11.6 kJ/m², which increased by 36.1% and 59.3%, respectively compared with those of untreated ones. With the prolongation of heat treatment time, the tensile strength and impact strength of the composite could reach up to 62.3 MPa and 11.0 kJ/m², which increased by 34.2% and 51.9%, respectively. DSC tests show that with the increasing heat treatment temperature and time the degree of crystallinity of the composites was enhanced by 11.4% and 8.6% respectively, however the heating temperature has much strong influence on the degree of crystallinity rather than holding time. XRD results show that heat treatment did not change the crystallographic structure of the composite. With the increasing heat treatment temperature, the thermal conductivity of the composite was 0.49 W/(m·K) and 0.42 W/(m·K) measured at 50^oC and 100^oC respectively. Correspondingly, which increased by 24.1% and 18.6%, respectively in comparison with those of the non-heat treated ones. With the increasing heat treatment time, the thermal conductivity of the composite could rach up to 0.46 W/(m·K) and 0.37 W/(m·K) at 50^oC and 100^oC, which increased by 14.6% and 5.9% in comparison to those of the non-heat treated ones. Besides, the heat treatment temperature presents much obvious influence on the enhancement of the thermal conductivity of the composite.