Thermoplastic composties of polystyrene: Effect of different wood species on mechanical properties
Article first published online: 9 MAR 2003
Copyright © 1989 John Wiley & Sons, Inc.
Journal of Applied Polymer Science
Volume 38, Issue 3, pages 413–439, 5 August 1989
How to Cite
Maldas, D., Kokta, B. V. and Daneault, C. (1989), Thermoplastic composties of polystyrene: Effect of different wood species on mechanical properties. J. Appl. Polym. Sci., 38: 413–439. doi: 10.1002/app.1989.070380303
- Issue published online: 9 MAR 2003
- Article first published online: 9 MAR 2003
- Manuscript Accepted: 18 JUL 1988
- Manuscript Received: 20 MAY 1988
Both softwood (spruce) and hardwood (aspen and birch) species in the form of different pulps (e.g., sawdust, chemithermomechanical pulp, explosion pulp and OPCO pulp) have been used (10–40 wt% composite) as reinforcing fillers for thermoplastic composites of polystyrene. Mechanical properties, are examined, e.g., tensile modulus, tensile strength at maximum point, and the corresponding elongation and energy as well as impact strength of compression molded composites. To improve the compatability of wood fibers which are hydrophilic and the polymer matrix which is hydrophobic, poly[methylene(polyphenyl isoeyanate)] (2 and 8 wt % of polymer) was used as a coupling agent. The mechanical properties of the treated composites are improved up to 30% in fiber content whereas a downward trend for untreated composites was observed when an increase in fiber content occurred. The overall improvements in mechanical properties due to the addition of isocyanate can be explained by the linkage of isocyanate molecules with fiber matrix through the chain of covalent bonds and the interaction of π-electrons of benzene rings of polystyrene as well as isocyanate. As a result, poly[methylene(polyphenyl isocyanate)] forms a bridge between fiber and polymer on the interfaces. This result is instrumental for efficient stress transfer between cellulose fibers and thermoplastics. The performance of different pulps of various wood species as reinforcing fillers for thermoplastic composites is also examined.