On The Mechanical Properties Of Bamboo/Vinyl Ester Resin Composites In Humid Environment

In recent years, people have put more attention to natural fiber reinforced composites. Because of the ability of moisture absorption, natural fibers can absorb much moisture during the periods of fabrication as well as application, leading to the decrease in the properties of fibers, resin and interface, resulting in the decrease of the entire property of the material and the shortening of service life. Therefore, it would be practical to study the effects of moisture absorption during the fabrication and application of the composites on their properties.The effects of chemical treatments on the properties of bamboo/vinyl ester composites in humid environment were studied with bamboo strips and vinyl ester as raw materials. Following investigations are included in the present study:(1) The bamboo strips were treated by acetylates and silane coupling after alkali treatment. The surface of the bamboo strips was observed by SEM and the results show that the surface of the bamboo strips is smooth before the treatment and, after the treatment, the suface becomes rougher and thin, and the colour turns into brown or nigger-brown. Moreover, the morphology of cellulose becomes more obvious after the treatments.(2) Specimens of bamboo/vinyl ester were prepared with untreated and treated bamboo strips, by acetylates and silane coupling, under different relative humidity environments (40, 60, 80 % RH). The mechanical properties of the specimens were tested. Results show that the sensitivity to humidity condition of bamboo is reduced through the the treatments of the bamboo strips, together with the decrease of the moisture absorption of the bamboo strips at different relative humidity environment, leading to the enhance of the impact property and bending property of the peecimens.(3) Speciments of bamboo/vinyl ester were prepared with untreated and treated bamboo strips, by acetylates and silane coupling, under 0 % RH environment and then dipped into water for different days. Results show that the anti-impact property and anti-bending property in water of the specimens are improved obviously and steadily after the acetylated treatement of the bamboo strips. However, the bending properties of the specimens are greatly deteriorated after the silane coupling treatment.