固相剪切碾磨对聚偏氟乙烯结构和介电性能的影响

利用固相剪切碾磨技术(S~3M)制备了高β晶含量的聚偏氟乙烯(PVDF)微米级粉体,研究了PVDF粉体的结构形态、粒径及粒径分布,碾磨遍数对粉体结晶结构和介电性能的影响。结果表明,固相力化学反应器强大的挤压和剪切作用可使PVDF中α晶转变为晶,从而有效提高PVDF粉体中β晶相对含量;随碾磨遍数增加,PVDF粉体β晶含量逐渐提高,未碾磨PVDF中的β晶相对含量为37%,碾磨15遍后β晶相对含量达90%以上;同时,介电常数则由1.20增加至10.77,提高约1个数量级。固相剪切碾磨技术为高介电性能材料的制备提供了新途径。

Effect of Solid State Shear Milling on Structure and Dielectric Properties of Poly(vinylidene fluoride)

Solid state shear milling (S3M) technology was adopted to prepare poly(vinylidene fluoride)(PVDF) micron powders with extremely highly relative fraction of β-phase.The structural form,partical size and partical size distribution of PVDF powders were analyzed,and the influence of milling cycles on the crystalline structure and the dielectric property of PVDF powders were also researched.The results show that ascribing to the strong compression and shear force of the pan-milling,the α-phase of PVDF is transformed to β-phase,thus increasing the relative fraction of β-phase,e.g.the relative fraction of β-phase increases to above 90 ％ after 15 cycles pan-milling,while the relative fraction of β-phase in unmilled sample is only 37％.Meanwhile,the dielectric constant of milled sample increases an order of magnitude compared with the unmilled sample,from 1.20 to 10.77.S3M technology provided a novel way for the preparation of high dielectric materials.