Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
Biomacromolecules. 2011 Nov 14;12(11):4057-62. doi: 10.1021/bm201079n. Epub 2011 Oct 19.
Wood cellulose nanofibril films with sodium carboxylate groups prepared from a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized pulp exhibited an extremely low oxygen permeability of 0.0008 mL μm m(-2) day(-1) kPa(-1) at 0% relative humidity (RH). Positron annihilation lifetime spectroscopy (PALS) was used to determine the pore sizes in wood and tunicate TEMPO-oxidized cellulose nanofibril (TOCN-COONa) films in a vacuum (i.e., at 0% RH). PALS analysis revealed that the pore size of the wood TOCN-COONa films remained nearly at 0.47 nm from the film surface to the interior of the film. This is probably the cause of this high oxygen-barrier properties at 0% RH. The crystalline structure of TOCN-COONa also contributes to the high oxygen-barrier properties of the wood TOCN-COONa films. However, the oxygen permeability of the wood TOCN-COONa films increased to 0.17 mL μm m(-2) day(-1) kPa(-1) at 50% RH, which is one of the shortcomings of hydrophilic TOCN-COONa films.
用 2,2,6,6-四甲基哌啶-1-氧自由基（TEMPO）氧化的纸浆制备的带羧酸钠基团的木质纤维素纳米纤维薄膜在 0%相对湿度（RH）时的氧气透过率极低，仅为 0.0008 mL μm m(-2) day(-1) kPa(-1)。正电子湮没寿命谱（PALS）被用于在真空中（即 0% RH 下）测定木材和被囊动物 TEMPO 氧化纤维素纳米纤维（TOCN-COONa）薄膜的孔径。PALS 分析表明，木材 TOCN-COONa 薄膜的孔径从薄膜表面到内部几乎保持在 0.47nm 不变。这可能是在 0% RH 下这种高氧气阻隔性能的原因。TOCN-COONa 的结晶结构也有助于提高木材 TOCN-COONa 薄膜的氧气阻隔性能。然而，木材 TOCN-COONa 薄膜的氧气透过率在 50% RH 时增加到 0.17 mL μm m(-2) day(-1) kPa(-1)，这是亲水性 TOCN-COONa 薄膜的一个缺点。
