title: Side-chain crystallization in alkyl-substituted cellulose esters and hydroxypropyl cellulose esters.
abstract: The differences in side chain crystallization behavior between cellulose esters (CEs) and hydroxypropyl cellulose esters (HPCEs) were systematically investigated by a combination of differential scanning calorimetry (DSC) and small and wide-angle X-ray scattering techniques. DSC investigation indicated that under the same side chain length, the fusion enthalpy and the number of crystallized CH2of CEs were smaller than HPCEs. At the same time, their d-spacing and molecular arrangements were also different from each other. For the CEs, the side chains are perpendicular to the main chain, while the side chains most probably tend to tilt to main chain in the HPCEs as was evidenced by X-ray scattering results. The phenomenon can be understood as a consequence of different flexibility of attachment bridges in both kinds of side chain polymers and the steric hindrance of methyl group in the hydroxypropyl group in HPCEs. In addition, the added hydroxypropyl substituents make the side chain length increasing.
authors.affiliation: School of Material Science and Engineering, East China Jiaotong University, Nanchang 330013, PR China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Renmin Street 5625, 130022 Changchun, PR China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Renmin Street 5625, 130022 Changchun, PR China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Renmin Street 5625, 130022 Changchun, PR China. Electronic address: liulz@ciac.ac.cn.
authors.forename: Lingzhi
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Renmin Street 5625, 130022 Changchun, PR China.
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Men
mesh_terms: D002152:Calorimetry, Differential Scanning; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry*; D003460:Crystallization; D004952:Esters / Q000737:chemistry*
chemical_list: D004952:Esters; D002482:Cellulose; C008079:hydroxypropylcellulose
keywords: Cellulose esters; Hydroxypropyl cellulose esters; Phase transition behavior; Side chain crystallization behavior