Abstract

Objective In order to solve the problem of insufficient mechanical properties of panels made from wood raw material particles and achieve high-value-added utilization of low-quality materials， the synergistic effect between poplar particles of different shapes and sizes is investigated， and the influences of particle shape， size， and their proportions on the properties of bismuth oxide-poplar composites are analyzed， aiming to achieve controllable optimization of material properties.

Methods First， using bismuth oxide and fast-growing poplar particles as raw materials， and under the conditions of a bismuth oxide mass fraction of 10% without any binder， powdered and fibrous poplar particles with sizes ≤ 180 μm and ≤ 425 μm were selected. The mass ratios of powdered to fibrous poplar particles were set to 1：0， 3：1， 1：1， 1：3， and 0：1， respectively. Five types of bismuth oxide-poplar composite specimens were prepared via warm-press forming process. Subsequently， the static bending strength and modulus of elasticity of the specimens were tested using a universal testing machine， and the stress-time and strain-time curves were obtained through compression creep tests. The fracture microstructure and surface roughness of the specimens were observed using a scanning electron microscope and a surface roughness tester， respectively. The water absorption rate and thickness swelling rate of the specimens were evaluated through 24 h water immersion tests. Finally， the effects of poplar particles with different sizes and size ratios on the mechanical properties， fracture characteristics， and water absorption of the bismuth oxide-poplar specimens were analyzed.

Results and Discussion As the proportion of fibrous poplar particles increased， the density of the bismuth oxide-poplar composite specimens gradually decreased， while the static bending strength and modulus of elasticity first increased and then decreased. The surface roughness， 24 h water absorption rate， and 24 h thickness swelling rate increased progressively， and the fracture mechanism of the specimens gradually shifted from brittle fracture to ductile fracture. When the mass ratio of powdered poplar particles to fibrous poplar particles was 1：3， the static bending strength of the specimens reached a maximum of 75 MPa. At a mass ratio of 3：1， the modulus of elasticity attained a maximum of 7 433 MPa. At a mass ratio of 1：1， the specimens exhibited the steady-state creep stress value of 2.66 MPa and the minimum total strain value of 0.058. Under these conditions， specimens exhibited the slowest transition into the steady-state creep stage， indicating good structural stability and safety.

Conclusion The shape and size of poplar particles have a significant effect on the properties of bismuth oxide-poplar composites. Mixing powdered and fibrous poplar particles at an appropriate mass ratio can produce a synergistic effect， leading to optimal overall performance of the composite.

Keywords： bismuth oxide；poplar particle； mass ratio； composite； mechanical property； water absorption property

Get Citation：Yan Jin， Zhang Liqiang， Luo Hong， et al. Effects of shape and size of poplar particles on properties of bismuth oxide-poplar composites［J］. China Powder Science and Technology， 2026， 32（4）： 1-12.

Received：2025-08-19， Revised： 2026-04-08，Online： 2026-06-09.

Funding：The research was supported by the National Natural Science Foundation of China (Grant No. 52205508), the Regional Joint Fund Project of the Natural Science Foundation of Hunan Province (Grant No. 2024JJ7640), and the Changsha Municipal of Natural Science Foundation (Grant No. kq2202288).

DOI：10.13732/j.issn.1008-5548.2026.04.014

CLC No.：S781.2； S781.3； TB44

Type Code：A

Serial No.：1008-5548（2026）04-0001-12