Emrah Peşman

Surface properties of bamboo and Scots pine impregnated with boron and copper based wood preservatives after accelerated weathering

In this study, we investigated the color, gloss and surface roughness of bamboo (Phyllostachys bambusoides) and Scots pine (Pinus sylvestris) samples impregnated with boron and copper based preservatives during accelerated weathering from 168 h to 672 h. Tanalith-E, ACQ, wolmanit-CB were used as copper-based chemicals, while a mixture of boric acid and borax (7:3; w/w) was used as the boron compound. Results showed that retention values of bamboo samples were lower than the retention values of Scots pine samples probably due to the bamboo’s anatomical structure and penetration characteristic. Bamboo surfaces became rougher and darker after impregnation and accelerated weathering compared to initial surfaces. Longer accelerated weathering periods seemed to have not a considerable effect on surface roughness of bamboo samples impregnated with copper based preservatives. Gloss of impregnated Scots pine samples increased with longer accelerated weathering period while gloss of bamboo samples decreased slightly with longer accelerated weathering period. Wolmanit-CB seemed to be most effective wood preservative for hindering color change and ensuring smooth surfaces after accelerated weathering. Color changes caused by accelerated weathering tended to be greater for impregnated bamboo samples than impregnated Scots pine samples.

Potential use of cotton dust as filler in the production of thermoplastic composites

The effect of cotton dust as filler on the mechanical and thermal properties of polypropylene composites was investigated and the results were compared with the properties of wood plastic composites. Cotton dust was obtained from the dust filtration system located in a textile manufacturing unit. Different mixtures of cotton dust (30 to 60 wt%) or wood flour (30 to 60 wt%) were compounded with polypropylene with a coupling agent (maleic anhydride grafted polypropylene 3 wt%) in a twin-screw co-rotating extruder. The test specimens were produced by injection molding machine. The tensile strength and flexural modulus of the specimens improved with the increase in the filler content. There was no significant difference in the strength and modulus values between the cotton dust and wood flour filled composites. The highest thermal stability was found to be in the composites produced with 40 wt% of cotton dust according to the results of differential scanning calorimetry analysis. Based on the findings obtained from the present study, the optimum mechanical and thermal properties for the filled polypropylene composites were found to be a 50/50/3 formulation of cotton dust, polypropylene, and maleic anhydride grafted polypropylene, respectively.

Influence of plum gum and sodium perborate addition on spruce kraft pulp properties during oxygen delignification

The aim of this study was to investigate the effects of plum gum liquor and sodium perborate addition to oxygen delignification process on spruce kraft pulp properties. Yields and viscosity of pulp were protected against oxidative attack, when kappa number of pulp was not changed by adding plum gum to oxygen delignification process. Delignification ratio improved by 7.4% without any viscosity loss by adding only 0.25% sodium perborate as active oxygen with plum gum liquor to the oxygen delignification process. It was found that crystallinity of pulp was improved by adding plum gum and sodium perborate to oxygen delignification. It was also determined that sodium perborate had an affirmative effect on delignification ratio, when plum gum affected pulp viscosity positively.