Effects of Alkali Treatment and Polyisocyanate Crosslinking on the Mechanical Properties of Kraft Fiber-Reinforced Unsaturated Polyester Composites

• Main Authors: Zhenhua Gao, Mingwei Di, Xiaofeng Zhang, Dawei Zhang
• Format: Article
• Language: English
• Published: North Carolina State University 2014-08-01
• Series: BioResources
• Subjects: Wood-plastic composites; Kraft fiber; Unsaturated polyester; Alkali pre-treatment; Polyisocyanate; Crosslinking; Mechanical properties
• Online Access: http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_09_4_5906_Gao_Alkali_Treatment_Polyisocyanate_Kraft

The effects of alkali treatment and polyisocyanate crosslinking on the mechanical properties of kraft fiber-reinforced UPE composites were investigated by means of tensile evaluation, SEM analysis, and XRD analysis. The results indicated that the alkali treatment decreased the tensile strength of the prepared composite before aging from 121 MPa to 97 MPa due to the decreased degree of crystallinity of the alkali-treated kraft fiber. Polyisocyanate crosslinking could apparently improve the mechanical properties and stability in terms of a 43% increase of non-aged tensile strength and 52% increase of hydrothermal-aged tensile strength compared with the controlled composite without crosslinking modification, which was attributable to the formation of strong chemical bonding between the interfaces of kraft fiber and polyester.