Cellulose Nanofibrils as Reinforcement in the Process Manufacture of Paper Handsheets

ABSTRACT

The objective of this study was to better understand the effect of micro/nanofibrils added as reinforcement on paper handsheets, their physical-mechanical performance and barrier properties, and to determine the ideal cellulose nanofibrils (CNF) proportion to increase such paper properties. Mechanically produced CNF were added at increasing amounts (0%, 2%, 5%, 8% and 10%) to commercial Eucalyptus pulp to produce paper handsheet samples. Morphology, crystallinity, physical-mechanical and air barrier properties of the paper handsheets were evaluated. The results suggested that adding CNF has decreased the presence of empty spaces inside and on the surface of the paper handsheets by up to 61% due to the interaction between fibers and nanofibrils. The paper handsheets became denser, more compact and resistant to passage of air, as well as with greater mechanical performance with higher CNF content (10%). The bursting index is approximately 5 times higher on paper with addition of 10% of CNF compared to control paper handsheets. There were significant gains in the studied properties without any change in CNF/fibers surface charge or the use of any cationic polymer to assist the retention of nanofibrils and fibers. This study highlights the potential of CNF as additives in papermaking process, increasing its properties.

GRAPHICAL ABSTRACT

摘要

本研究的目的是更好地了解添加的微/纳米纤维作为增强材料对纸页的影响、其物理机械性能和阻隔性能,并确定理想的纤维素纳米纤维(CNF)比例,以提高纸页性能. 机械生产的CNF以增加的量(0%、2%、5%、8%和10%)添加到商业桉树纸浆中,以生产纸张手抄纸样品. 评估了纸页的形态、结晶度、物理机械性能和空气阻隔性能. 结果表明,由于纤维和纳米纤维之间的相互作用,添加CNF可将纸页内部和表面的空隙减少高达61%. 纸页变得更致密、更紧凑、更耐空气通过,并且随着CNF含量的增加(10%)具有更高的机械性能. 与对照纸张相比,添加10%CNF的纸张的破裂指数大约高出5倍. 在CNF/纤维表面电荷没有任何变化或使用任何阳离子聚合物帮助保留纳米纤维和纤维的情况下,所研究的性能有显著的提高. 这项研究突出了CNF作为造纸过程添加剂的潜力,提高了其性能.

KEYWORDS:

• Composite fibers
• kraft paper
• mechanical properties
• cellulose microfibrils (CMF)
• nanocellulose
• papermaking

关键词:

• 复合纤维
• 牛皮纸
• 力学性能
• 纤维素微纤维(CMF)
• 纳米纤维素
• 造纸

Acknowledgments

The author expresses special thanks to Cellulose and Paper Laboratory of the Universidade Federal de Viçosa (UFV, Brazil) and Forest Nanotechnology Laboratory of the Universidade Federal de Lavras (UFLA, Brazil) for supporting the experimental work. This study was funded by CNPq (National Council for Scientific and Technological Development, Brazil, grant number 405085/2016-8), CAPES (Higher Education Personnel Improvement Coordination, Brazil), and FAPEMIG (Foundation for Research Support of the State of Minas Gerais, Brazil, grant number APQ-00509-14). LR Costa was supported by CAPES grants.

Disclosure statement

There is no conflict of interests regarding the submission.