State Key Laboratory of Pulp and Paper Engineering, Plant Fiber Research Center, South China University of Technology, Guangzhou, 510640, China.
Guangdong Plant Fiber High-Valued Cleaning Utilization Engineering Technology Research Center, South China University of Technology, Guangzhou, 510640, China.
Sci Rep. 2021 Jun 7;11(1):11918. doi: 10.1038/s41598-021-91420-y.
Recycled paper and some hardwood paper often display poorer mechanical properties, which hinder its practical applications and need to be addressed. In this work, cellulose nanofibrils (CNFs) obtained by a combined process of enzymatic hydrolysis and grinding (EG-CNFs), grinding and microfluidization (GH-CNFs) or TEMPO-mediated oxidation and grinding (TE-CNFs) were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Moreover, CNFs were made into films on which some characterizations including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis transmittance spectroscopy were implemented. Results showed that CNF fibrillation was promoted as times of passes increased in microfluidization, and CNFs pretreated by enzyme possessed shorter length. Crystallinity of CNFs was related to CNF manufacturing methods, while CNF films' transparency was correlated to CNF diameter distributions. Moreover, CNFs were applied with different dosages on recycled and hardwood paper. Lengths of CNFs, strength of CNF network, and pulp properties were critical factors affecting the mechanical strength of CNFs-enhanced paper. GH-CNFs showed better strengthened effect on tensile strength of paper than TE-CNFs and EG-CNFs. The best overall improvement was achieved at GH-CNF10 dosage of 5.0 wt% on hardwood paper. The increment of tensile index, burst index, and folding endurance were 108.32%, 104.65%, and 600%, respectively. This work aims to find out the relationship between production methods and morphologies of CNFs and how the morphological characteristics of CNFs affecting the mechanical performance of paper when they are added as strength additives.
再生纸和一些硬木纸通常显示出较差的机械性能，这阻碍了它们的实际应用，需要加以解决。在这项工作中，通过酶解和研磨（EG-CNFs）、研磨和微流（GH-CNFs）或 TEMPO 介导的氧化和研磨（TE-CNFs）的组合工艺获得的纤维素纳米纤维（CNFs）通过扫描电子显微镜（SEM）和原子力显微镜（AFM）进行了表征。此外，将 CNFs 制成薄膜，并对其进行了包括 X 射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和紫外-可见透光率光谱在内的一些特性的表征。结果表明，随着微流处理中通过次数的增加，CNF 的纤维化得到了促进，而经过酶预处理的 CNF 具有更短的长度。CNFs 的结晶度与 CNF 的制造方法有关，而 CNF 薄膜的透明度与 CNF 直径分布有关。此外，将 CNF 以不同剂量添加到再生纸和硬木纸上。CNFs 的长度、CNF 网络的强度和纸浆性能是影响 CNF 增强纸机械强度的关键因素。GH-CNFs 对纸的拉伸强度的增强效果优于 TE-CNFs 和 EG-CNFs。在硬木纸上，GH-CNF10 用量为 5.0wt%时，整体改善效果最佳。拉伸指数、耐破指数和耐折度分别提高了 108.32%、104.65%和 600%。这项工作旨在找出 CNFs 的生产方法和形态之间的关系，以及当 CNFs 作为增强剂添加到纸张中时，CNFs 的形态特征如何影响纸张的机械性能。
