Nanocomposites of poly(vinylidene fluoride) with organically modified silicate

被引:199
作者
Buckley, J
Cebe, P [1 ]
Cherdack, D
Crawford, J
Ince, BS
Jenkins, M
Pan, JJ
Reveley, M
Washington, N
Wolchover, N
机构
[1] Tufts Univ, Dept Phys & Astron, Medford, MA 02155 USA
[2] Rochester Inst Technol, Dept Biol, Rochester, NY 14623 USA
[3] Rochester Inst Technol, Dept Biotechnol, Rochester, NY 14623 USA
[4] Rochester Inst Technol, Dept Chem, Rochester, NY 14623 USA
[5] Gallaudet Univ, Dept Biol, Washington, DC 20002 USA
基金
美国国家科学基金会;
关键词
nanocomposites; organically modified silicates; poly(vinylidene fluoride);
D O I
10.1016/j.polymer.2006.02.012
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
We report a study of the impact of cold crystallization on the structure of nanocomposites comprising poly(vinylidene fluoride) (PVDF) and Lucentite STN (TM) organically modified silicate (OMS). Nanocomposites were prepared from solution over a very wide composition range, from 0.01 to 20% OMS by weight. Thermal preparation involved cold crystallization at 145 degrees C of quenched, compression-molded plaques. Static and real-time wide and small angle X-ray scattering (WAXS, SAXS), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were used to investigate the crystalline phase of PVDF. For OMS content greater than 0.50 wt%, WAXS studies show that that the silicate gallery spacing increases modestly in the nanocomposites compared to neat OMS film, indicating a level of polymer intercalation. Using Gaussian peak fitting of WAXS profiles, we determine that the composition range can be divided into three parts. First, for OMS greater than 0.5 wt%, alpha phase fraction, phi(alpha), is insignificant (phi(alpha) similar to 0-0.01). Second, at the intermediate range, for OMS between 0.5 wt% down to 0.025 wt%, beta phase dominates and the beta fraction, phi(beta), is related to alpha by phi(beta) > phi(alpha). Third, below 0.025 wt% OMS, alpha dominates and phi(alpha) > phi(beta). The ability ol'small amounts of OMS (>= 0.025 wt%) to cause beta crystal domination is remarkable. Overall, crystallinity index (from the ratio of WAXS crystal peak area to total area) ranges from about 0.36 to 0.51 after cold crystallization. Real-time WAXS studies during heating of initially cold crystallized nanocomposites show that there is no inter-con version between the alpha and beta phase PVDF crystals, where these crystals coexist at room temperature. While all samples showed a strong SAXS Bragg peak, indicating existence of two-phase lamellar stacks, the sample containing predominantly beta phase had poorly correlated lamellar stacks, compared to samples containing predominantly alpha phase. (c) 2006 Elsevier Ltd. All rights reserved.
引用
收藏
页码:2411 / 2422
页数:12
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