Journal of Forestry Research, 15(1): 77-79 (2004)

77

Effects of different modifiers on the properties of wood-polymer

composites

XU Min, CAI Zhi

Material Science and Engineering College, Northeast Forestry University, Harbin 150040, P. R. China

Abstracts: Wood-polymer composites (WPC) were prepared from wood fiber and four kinds of plastics such as PE, PS, ABS, and SAN. The effects of different modifiers on the mechanical properties of the composites were studied. The results showed modifiers could raise the bonding strength of wood fiber with polymer and improve the mechanical properties of the composites. Different modifiers had different effects on the properties of wood-polymer composites, and comparatively the modifier of iso-cyanate produced a better result. Wood-polymer composite takes not only the advantages of both wood fiber and polymer, but waterproof, dimensional stability and dynamic strength are also significantly improved.

Key word: Wood fiber; Thermoplastic polyester; Wood-polymer composites; Modifier; Mechanical properties CLC number: TB332 Document code: A Article ID: 1007-662X(2004)01-0077-03

Introduction

Wood-polymer composites (WPC) are made from the wood fiber and plastics through the given technology. They have following benefits: ·increasing strength and stiffness, reducing the variability in mechanical properties, which allows for higher design values, increasing service ability and fatigue performance of the product, and enhancing durability and dimensional stability of products.

Wood-polymer composites have been studied for more than 40 years by researchers. Especially these years, as development of high polymer product industry, recycling high polymer has been an important problem demanding promot solution (Yang et al. 2000). In addition, because of the decrease of the forest resource, the high cost and un-stability of dimension of the forest products, many studies have been carried out on the wood-polymer composites increasingly (Yin et al. 2002) It was reported that one of the super development fields of forest products in 21st century is to increase the additional properties of wood-polymer composites fitting in with various situations (Zhang et al. 2001). How to improve wood-polymer composites product quality, decrease cost, improve industrial process is im-portant for recycling plastic and exploiting poor wood.

Wood is a natural polymer material and its interface has a large quantity of functional polar groups. In the course of making wood-polymer composites, it is hard to get the adequate compatibility between the surface of hydrophily

Foundation item: This study was supported by the Harbin Technology Tackle Key Plan (Development Research of Wood-Polymer Composites with High Wood Matrix) and by Heilongjing Nature Science Fund (Composite Mechanism Study of the Wood Polymer).

Biography: XU Min (1963-), Female, Associate professor in Material Sci-ence and Engineering College, Northeast Forestry University, Harbin 150040, P. R. China. E-mail: Received date: 2003-10-13 Responsible editor: Chai Ruihai

wood and adhydrophily polymer, because of the energy difference in their interface. Therefore, to improve the po-larity of the wood surface and decrease the energy differ-ence in the interface is the effective way to increase the mechanical properties of wood-polymer composites (Yan et al. 1999).

In this study, wood-polymer composites were prepared from wood fiber and four kinds of plastics such as PE (Polyethylene), PS (Polystyrene), ABS (Acrylonitrile- Buta-diene-Styrene), SAN (Styrene-Acrylonitrile). In addition, the effects of two modifiers on the mechanical properties of composites were studied. Thus, it will provide the reference basis for the future research of the wood-polymer compos-ites.

Materials and methods

Test apparatus and meterials

High-speed pulverizer, 50-t test performer, 100-t test heating press, rotor press, AG-10TA DJ universal testing machine, and LJ500 tensile force machine were used in test. Test materials include Wood fiber, PE, PS, ABS, SAN, dicumyl peroxide, isocyanate resin, and acetone

Test method

Process of wood fiber: Wood fiber has been shivered by mix machine and dried to 15% of water content. Then they are covered by polymer film and prepared for using.

Process of polymer: Polymer was shivered by high-speed pulverizer and screened with a sieve to receive homogeneous compound of wood fiber and polymer

Preparation of bar plate: Wood fiber was put into a rotor press, sprayed with dicumyl peroxide or matching liquor of acetone and isocyanate resin, after rotating several cycles, a polymer of 20 or 34 mesh was put into the rotor press. By adequate amalgamation, they were made to a 320 mm×340 mm loose bar plate by using of hand lay-up. At