title: Changes in the microstructure and properties of aspen chemithermomechanical pulp fibres during recycling.
abstract: The effects of recycling on the microstructure and properties of bleached aspen chemithermomechanical pulp (CTMP) fibres were systematically investigated. The low-temperature nitrogen adsorption and atomic force microscopy results showed that a substantial amount of large pores and most of the very small pores in the fibre wall closed and the fibre surface became less coarse and porous during recycling. The partial cocrystallisation of cellulose microfibrils took place, as reflected in the increment of the cellulose crystallinity and the width of the crystallite in the 0 0 2 lattice plane. These irreversible structural changes caused significant hornification of the recycled fibres, leading to the loss of swelling and bonding capability. The decrease of the tensile index, burst index, and tear index further demonstrated the deterioration of the fibre properties. However, the single-fibre strength considerably increased after recycling, which was mainly due to the enlarged cellulose aggregates in the fibre wall.
authors.affiliation: Key Laboratory of Pulp & Paper Science and Technology of the Ministry of Education, Qilu University of Technology, Jinan 250353, Shandong, China. Electronic address: fyingjuan@163.com.
authors.forename: Yingjuan
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Key Laboratory of Pulp & Paper Science and Technology of the Ministry of Education, Qilu University of Technology, Jinan 250353, Shandong, China.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Wang
authors.affiliation: Key Laboratory of Pulp & Paper Science and Technology of the Ministry of Education, Qilu University of Technology, Jinan 250353, Shandong, China.
authors.forename: Dejuan
authors.initials: D
authors.lastname: Li
authors.affiliation: Key Laboratory of Pulp & Paper Science and Technology of the Ministry of Education, Qilu University of Technology, Jinan 250353, Shandong, China.
authors.forename: Zhaojiang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Huatai Group Corp. Ltd., Dongying 257335, Shandong, China.
authors.forename: Fengshan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Pulp & Paper Science and Technology of the Ministry of Education, Qilu University of Technology, Jinan 250353, Shandong, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Meng
authors.affiliation: Organic Chemistry Laboratory, Taishan University, Taian 271021, Shandong, China; Huatai Group Corp. Ltd., Dongying 257335, Shandong, China. Electronic address: qmh@qlu.edu.cn.
authors.forename: Menghua
authors.initials: M
authors.lastname: Qin
mesh_terms: D055595:Mechanical Phenomena; D016062:Porosity; D059027:Recycling; D013499:Surface Properties; D013696:Temperature; D014197:Trees / Q000737:chemistry*
keywords: Aspen CTMP; Bonding capability; Crystallinity; Hornification; Pore characteristics; Recycling