title: Homogeneous ring opening graft polymerization of ɛ-caprolactone onto xylan in dual polar aprotic solvents.
abstract: Homogeneous ring-opening graft polymerization (ROGP) of ɛ-caprolactone (ɛ-CL) onto xylan was investigated in dual polar aprotic solvents, N,N-dimethylformamide/lithium chloride (DMF/LiCl), N,N-dimethylacetamide/LiCl (DMAc/LiCl), and 1-methyl-2-pyrrolidinone/LiCl (NMP/LiCl). The effects of reaction solvents, temperature, and the molar ratio of ɛ-CL to anhydroxylose units (AXU) on the degree of substitution (DS) of xylan-graft-poly(ɛ-caprolactone) (xylan-g-PCL) copolymers and the degree of polymerization (DP) of the attached PCL side chains were investigated. FT-IR and NMR analyses provided the evidence of the occurrence of ROGP reaction. The thermal stability of xylan increased upon ROGP reaction due to the increased length of PCL side chains. With the increased attachment of PCL side chains, the tensile strength and Young's modulus of the films decreased, whereas the elongation at break increased. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations provided the evidences of the increased film properties due to the attachment of PCL side chains.
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China; Institute of New Energy and New Material, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou 510642, PR China.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China. Electronic address: chfliu@scut.edu.cn.
authors.forename: Chuanfu
authors.initials: C
authors.lastname: Liu
authors.affiliation: Institute of New Energy and New Material, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou 510642, PR China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China; Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, PR China.
authors.forename: Runcang
authors.initials: R
authors.lastname: Sun
keywords: Dual polar aprotic solvents; Ring-opening graft polymerization; Xylan; ɛ-Caprolactone