PVA浓度对电纺制备ZnO纳米纤维吸波性能的影响

Effect of PVA concentration on microwave absorption properties of ZnO nanofibers prepared by electrospinning

采用静电纺丝法制备ZnO纳米纤维,研究聚乙烯醇(PVA)浓度对ZnO纳米纤维微观形貌、介电性能和吸波性能的影响规律。结果表明:随着PVA浓度从6%增至10%,ZnO纳米纤维直径变细,但珠结增加,粗细不均。当PVA浓度为8%时,ZnO纳米纤维直径较细、粗细均匀、表面光滑、珠结较少,形貌最好。此时,其介电常数达到最高值,实部为15.4~20.8,虚部为3.6~4.7,并在较薄的厚度下具有最优的吸波性能。当70%(质量分数/%,下同)ZnO纳米纤维/石蜡样品的厚度为1.3 mm时,反射率低于–5 dB的吸收带宽达到5.4 GHz(12.6~18 GHz),最小反射率为–16.6 dB。此外,石蜡含量也对样品的介电性能和吸波性能具有重要影响,随着石蜡含量的增加,样品的介电常数降低,当石蜡含量为30%和20%时,样品具有较好的吸波性能。

ZnO nanofibers were prepared by electrospinning method in this work.The effects of PVA concentration on the morphology,dielectric properties and microwave absorption properties of ZnO nanofibers were studied.Results show that with the concentration of PVA increases from 6%to 10%,the diameter of ZnO nanofibers becomes smaller,but the knots increase and the thickness is uneven.When the concentration of PVA is 8%,ZnO nanofibers show the best morphology with fine and uniform diameter,smooth surface and less knots.At this point,the complex permittivity of it reaches the highest value with a real part of 15.4-20.8 and imaginary part of 3.6-4.7.It also has an optimum microwave absorption property in a thinner thickness.When the thickness of 70%ZnO nanofiber/paraffin sample is 1.3 mm,the microwave absorption bandwidth of reflection loss below–5 dB reaches 5.4 GHz(12.6-18 GHz),the minimum reflection loss is–16.6 dB.In addition,the content of paraffin also has an important effect on the dielectric property and microwave absorption property of the sample.The complex permittivity of the sample decreases as increasing the content of paraffin.When the content of paraffin is 30%and 20%,the samples have good microwave absorption properties.