Leite Liliane S F, Le Gars Manon, Azeredo Henriette M C, Moreira Francys K V, Mattoso Luiz H C, Bras Julien
Graduate Program in Materials Science and Engineering (PPGCEM), Federal University of São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP, Brazil; Nanotechnology National Laboratory for Agribusiness, LNNA, Embrapa Instrumentation, R. XV de Novembro, 1452, 13560-979 São Carlos, SP, Brazil; University Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38400 Grenoble, France.
University Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38400 Grenoble, France.
Int J Biol Macromol. 2024 Sep 16;280(Pt 3):135726. doi: 10.1016/j.ijbiomac.2024.135726.
In this study, gelatin/carboxylated cellulose nanocrystal (cCNC) bionanocomposite films were developed as an eco-friendly alternative to non-biodegradable flexible plastic packaging. Cellulose nanocrystals were modified by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation (cCNC) to strategically interact with amino groups present in the gelatin macromolecular backbone. Gelatin/cCNC bionanocomposite films (0.5-6.0 wt% cCNC) obtained by solution casting were transparent to visible light while displayed high UV-blocking properties. The chemical compatibility between gelatin and cCNC was deepened by electrostatic COO/NH interactions, as detected by FTIR spectroscopy and morphologically indicated by scanning electron microscopy (SEM). Accordingly, Young's modulus and tensile strength of films were largely increased by 80 and 64 %, respectively, specifically near the cCNC percolation threshold (4 wt%), whereas the water vapor permeability (WVP) was reduced by 52 % at the optimum 6.0 wt% cCNC content in relation to the non-reinforced gelatin matrix (0.10 vs. 0.18 g HO mm m h kPa). The oxygen transmission rates (OTR) of the gelatin/cCNC bionanocomposites were < 0.01 cm m- day, making them technically competitive to most promising biopolymers like polycaprolactone (PCL) and poly(lactic acid) (PLA). This study reveals how TEMPO-oxidized cellulose nanocrystals can broaden the performance of biodegradable gelatin films for use in packaging. The gelatin/cCNC bionanocomposites also represent an effective approach for designing newly sustainability-inspired flexible materials from the surface modification of nanocelluloses targeting specific interactions with protein structures.
在本研究中，明胶/羧化纤维素纳米晶体（cCNC）生物纳米复合薄膜被开发出来，作为不可生物降解柔性塑料包装的环保替代品。纤维素纳米晶体通过2,2,6,6 - 四甲基哌啶 - 1 - 氧基（TEMPO）介导的氧化反应（cCNC）进行改性，以便与明胶大分子主链中存在的氨基进行策略性相互作用。通过溶液浇铸获得的明胶/cCNC生物纳米复合薄膜（cCNC含量为0.5 - 6.0 wt%）对可见光透明，同时具有高紫外线阻隔性能。通过傅里叶变换红外光谱（FTIR）检测发现，明胶与cCNC之间的化学相容性通过静电COO/NH相互作用得到增强，扫描电子显微镜（SEM）在形态上也表明了这一点。相应地，薄膜的杨氏模量和拉伸强度分别大幅提高了80%和64%，特别是在接近cCNC渗滤阈值（4 wt%）时，而相对于未增强的明胶基质，在最佳的6.0 wt% cCNC含量下，水蒸气透过率（WVP）降低了52%（0.10对0.18 g HO mm m h kPa）。明胶/cCNC生物纳米复合材料的氧气透过率（OTR）< 0.01 cm m - day，这使得它们在技术上与聚己内酯（PCL）和聚乳酸（PLA）等最有前景的生物聚合物具有竞争力。这项研究揭示了TEMPO氧化的纤维素纳米晶体如何扩展可生物降解明胶薄膜在包装中的性能。明胶/cCNC生物纳米复合材料也代表了一种有效的方法，即通过对纳米纤维素进行表面改性以实现与蛋白质结构的特定相互作用，从而设计出新型的受可持续性启发的柔性材料。
