Abstract: Fiber morphology, chemical composition and alkaline peroxide mechanical pulp (APMP) properties of three kinds of fast-growing black poplar(Populus nigra) crotches(ZY)were studied. Results of fiber morphology analysis are as follows: average fiber length 0.6mm, fiber width 20μm, fiber length-width ratio value 30, cell wall thickness-lumina ratio 0.5-0.6, fine content 10%-20%, fiber coarseness 8-10mg (based on 100m). Results of chemical composition are as follows: 1% NaOH extractives 22%, benzene-ethanol extractives 2.0%, nitro-ethanol cellulose 44%-47%, pentosan 24%-25%, acid insoluble lignin 18%-21%. The results showed that fast-growing black poplar crotches have smaller cell wall thickness-lumina ratio and fiber coarseness, less fine content, lower extractives content, low lignin content, low pentosan content, which are favorable for paper- and pulp-making. However, physical strengths of the paper are significantly adverse because of the short fiber length and small fiber length-width ratio. APMP pulps from fast-growing black poplar crotches using APMP process are obtained. The results show that the APMP pulp strength properties of crotches without bark are superior to crotches with bark, but inferior to bodywood.

Key words: black poplar, crotches, fiber morphology, alkaline peroxide mechanical pulp