Effect of recycling on the mechanical properties of wood fiber–polystyrene composites. Part I: Chemithermomechanical pulp as a reinforcing filler

Abstract The feasibility for recycling composites of polystyrene‐hardwood aspen fiber (chemithermomechanical pulp or CTMP) was tested by evaluating the mechanical properties and dimensional stability of the original polymer and the recycled composites. The mechanical properties and dimensional stability of composites were investigated under extreme conditions (e.g., exposure to boiling water and at room temperature as well as exposure to +105°C and −20°C). The influence of coupling agent, e.g., 3% poly[methylene (polyphenyl isocyanate)] (PMPPIC), and various treatments, e.g., fiber coated with 10% polymer +8% PMPPIC and grafted with polystyrene 89.1% add‐on, on the properties of the composites have also been studied. Compared with the original composites, the mechanical properties and dimensional stability of the recycled composites did not change significantly even after exposure to extreme conditions. Moreover, the treated composites offered improved properties compared with nontreated and original polymer under all experimental conditions.