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氮化硼纳米片取向提高聚丙烯酸酯复合压敏胶的导热性能
Oriented boron nitride nanosheets to enhance the thermal conductivity of polyacrylate composite pressure sensitive adhesive
【摘要】 传统构建导热网络的方法需要昂贵的设备和复杂的工艺。本文提出了一种通过压延工艺构建取向氮化硼纳米片(BNNSs)/聚丙烯酸酯复合压敏胶(PSA)的策略。聚丙烯酸酯压敏胶制备采用基于紫外光引发、本体法聚合的方法,结合压延工艺,成功制备了1~5层涂覆的复合压敏胶(m-BNNSs/PSAs-Ori)。与乳液和溶剂型压敏胶相比,制备过程不含有机溶剂和需要干燥的介质,环境友好。对其导热系数、有序性、微观形貌、压敏性、黏弹性、热扩散能力以及电绝缘性能进行了研究。研究结果表明:(1)复合压敏胶的导热系数随导热填料含量的增加而提升,仅涂覆单层压敏胶的复合材料的导热系数最低,增加涂覆层数可显著提高复合压敏胶的导热系数。当填料含量为25%时,涂覆3层和5层的复合压敏胶的导热系数分别较纯压敏胶提升了474%和543%。(2)经过多次涂覆与双辊剪切处理后,有机化氮化硼纳米片(m-BNNSs)的有序程度得到提高,有利于促进声子传输并降低声子散射。(3)随着涂覆次数增加,纳米片逐渐趋向于沿“平面”方向形成平行排列,该观察结果与X射线衍射分析的结论一致。(4)随着涂覆次数增加,材料的180°剥离强度相应提高,胶粘剂层间相互作用增强,其内聚力亦得到改善。引入改性氮化硼纳米片(m-BNNSs)填料会使材料的环形初粘力出现轻微下降。(5)添加改性氮化硼纳米片降低了复合压敏胶的tanδ值,其中涂覆5层复合压敏胶的tanδ最低。涂覆5层的样品的玻璃化转变温度(T_g)也较纯压敏胶有所提高。(6)复合压敏胶的热响应性随着填料含量的增加而增强,热传导效果显著,进一步证实了增加涂覆和剪切的数量对于提高导热系数的重要性。(7)与单层压敏胶相比,5次涂覆、剪切压敏胶的表面电阻率和体积电阻率都出现了略微降低,其中表面电阻率差别不大,体积电阻率下降趋势较为明显,但完全可以满足微型电子器件对内部隔膜材料的电绝缘性能要求。(8)总之,当取向氮化硼纳米片/聚丙烯酸酯复合压敏胶(m-BNNSs/PSA-Ori)中,填料含量为25%时,涂覆5层的样品的导热系数高达0.955 2 W/(m·K),与单层复合压敏胶相比,m-BNNSs/PSA-Ori复合压敏胶的导热系数显著提高,且保持材料的压敏性能,为热界面粘接材料的工业化提供了新的思路。
【Abstract】 The traditional method of constructing a thermal conductive network requires expensive equipment and complex processes. A strategy for constructing oriented boron nitride nanosheets(BNNSs)/polyacrylate composite pressure sensitive adhesive(PSA) through calendering process was proposed in this article.Polyacrylate pressure sensitive adhesive was prepared by the method based on UV initiation and bulk polymerization,combined with the calendering process,and one to five layers of composite pressure sensitive adhesive(m-BNNSs/PSAs-Ori) were successfully prepared. Compared with the emulsion and solvent-based pressure sensitive adhesive,the preparation process did not contain organic solvents and media that need to be dried,and was environmentally friendly. Its thermal conductivity,orderliness,microscopic morphology,pressure sensitivity,viscoelasticity,thermal diffusion ability,electrical insulation properties were also studied.The research results showed that,(1) The thermal conductivity of composite pressure sensitive adhesive increased with the increase of thermal conductive filler content,and the composite material coated with only a single layer of pressure sensitive adhesive had the lowest thermal conductivity.Increasing the number of coating layers could significantly improve the thermal conductivity of composite pressure sensitive adhesive.When the filler content was 25%,the thermal conductivity of the composite pressure sensitive adhesive coated with 3 and 5 layers was increased by 474% and 543% respectively compared to pure pressure sensitive adhesive.(2) After multiple coatings and double roll shear treatments,the orderliness of organic boron nitride nanosheets(m-BNNSs) was improved,which was beneficial for promoting phonon transport and reducing phonon scattering(.3) With the increase of coating times,the nanosheets gradually tended to form parallel arrangements along the "plane" direction,which was consistent with the conclusion of X-ray diffraction analysis(.4) With the increase of coating times,the 180° peel strength of the material was correspondingly improved,the interlayer interaction of the adhesive was enhanced,and its cohesion was also improved.The introduction of modified boron nitride nanosheets(m-BNNSs) filler would result in a slight decrease in loop tack force of the material(.5) The addition of modified boron nitride nanosheets reduced the tanδ value of the composite pressure sensitive adhesive,with the lowest tanδ value observed when coated with 5 layers of composite pressure sensitive adhesive.The glass transition temperature(Tg) of the sample coated with 5 layers was also higher than that of pure pressure sensitive adhesive.(6) The thermal responsiveness of composite pressure sensitive adhesive increased with the increase of filler content,and the thermal conductivity effect was significant,further confirming the importance of increasing the amount of coating and shearing for improving thermal conductivity(.7) Compared with single-layer pressure sensitive adhesive,the surface resistivity and volume resistivity of the adhesive coated and sheared 5 times showed a slight decrease,with little difference in surface resistivity and a more obvious decrease in volume resistivity.However,it could fully meet the electrical insulation performance requirements of microelectronic devices for internal diaphragm materials.(8) In summary,when the filler content in the oriented boron nitride nanosheets/polyacrylate composite pressure sensitive adhesive(m-BNNSs/PSA-Ori) was 25%,the thermal conductivity of the sample coated with 5 layers reached 0.955 2 W(/m·K).Compared with the single-layer composite pressure sensitive adhesive,the thermal conductivity of the m-BNNSs/PSA-Ori composite pressure sensitive adhesive was significantly improved while maintaining the material’s pressure sensitive properties,providing a new idea for the industrialization of thermal interface bonding materials.
【Key words】 boron nitride nanosheets; light-initiated polymerization; thermal conductivity; orientation; pressure sensitive adhesive;
- 【文献出处】 中国胶粘剂 ,China Adhesives , 编辑部邮箱 ,2025年12期
- 【分类号】TQ436.3
- 【下载频次】21