聚乙烯醇缩丁醛的甲苯-乙醇溶液及其非溶剂诱导相分离研究  

Toluene-Ethanol Solution of Polyvinyl Butyral and Nonsolvent-Induced Phase Separation

作　　者：任海东 曹秀华 赵亮 唐博武 罗继业 郑华德[3] 高粱 REN Haidong;CAO Xiuhua;ZHAO Liang;TANG Bowu;LUO Jiye;ZHENG Huade;GAO Liang(State Key Laboratory of Advanced Materials and Electronic Components,Guangdong Fenghua Advanced Technology Holding Co.,Ltd.,Zhaoqing 526020,Guangdong,China;School of Light Industry and Chemical Engineering,Guangdong University of Technology,Guangzhou 510006,China;School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]广东风华高新科技股份有限公司,新型电子元器件关键材料与工艺国家重点实验室,广东肇庆526020 [2]广东工业大学轻工化工学院,广州510006 [3]华南理工大学材料科学与工程学院,广州510641

出　　处：《功能高分子学报》2022年第4期328-338,I0002,共12页Journal of Functional Polymers

摘　　要：在片式多层陶瓷电容器(MLCC)的流延工艺中,甲苯-乙醇混合溶剂是黏合剂聚乙烯醇缩丁醛(PVB)广泛采用的溶剂体系。本文探讨了甲苯与乙醇的体积比、PVB浓度以及流延成膜的相对湿度等因素对溶液中PVB构象以及凝聚态膜片结构的影响。PVB中存在由烷侧链排列形成的玻璃区以及由链缠结而成的无定形区。乙醇是PVB的良性溶剂,通过溶胀玻璃区,使得PVB链更加舒展;甲苯可以有效降低PVB与溶液的摩擦,并通过“成核-生长”机制发生粗化聚并,导致分子间相互作用逐渐增大。较高湿度会造成膜片缺陷;混合溶剂中乙醇的体积分数过高易形成缺陷;缺陷几乎不影响膜的有效模量以及热力学性能。The emergency of micro/nanoelectronic systems and miniaturized portable devices raises urgent demand on miniaturized and integrated multi-layer ceramic capacitors(MLCC).For MLCC fabrication,tape-casting technology is one of the key processes,where routinely using toluene-ethanol solution of polyvinyl butyral(PVB)as a binder.Thus,the solution properties and their gelation play crucial roles in suppressing the flaws(e.g.,pinhole and local heterogeneity)in the dielectric layer.However,the effects of volume ratio of toluene to ethanol have yet been investigated in detail.This work decouples the effects of toluene and ethanol on the intermolecular,intramolecular and PVB-solvents interactions,and further understands the effects of solution’s compositions on gelation process.It is found that ethanol is a good solvent of PVB,through the expansion of the glassy region as structured by the packing of alkyl side chains,while toluene can effectively reduce the friction between PVB chains and solvents.Upon being exposed to atmosphere,PVB in solutions undergoes coarsening and coalescence through"nucleation-growth"mechanism.When the relative humidity is low in atmosphere,the compositional trajectory cannot cross the binodal curve and thus produce dense morphology,while high relative humidity will cause defects because the compositional trajectory crosses the binodal or spinodal curves.The defects almost do not affect the effective modulus of PVB film and thermomechanical properties.This work provides reference significance for screening PVB polymer,solvent system and film forming conditions in MLCC casting process.

关 键 词：片式多层陶瓷电容器 聚乙烯醇缩丁醛 溶解性 相分离 湿度 

分 类 号：O631[理学—高分子化学]