Experimental study on durability of wood–plastic composites by coupling dry–wet cycles and seawater environment

Abstract

The durability of wood-plastic composites (WPCs) exposed to seawater dry-wet cycles were investigated. The most detrimental cycles were evaluated by the orthogonal design method. The physical properties, structural strength, chemical characteristics, and thermal stability of WPC materials under the worst seawater dry-wet (W-SDW) cycles were described based on discoloration/water absorption/ thickness swelling, hardness/impact strength, Fourier transform infrared spectra, and thermogravimetric analysis results, respectively. The results showed that the W-SDW cycles were: immersion temperature of 60 C, immersion time of 4 h, drying temperature of 70 C, and drying time of 3 h. The exposure to W-SDW cycles degraded the fiber-matrix interface interaction, increasing discoloration, water absorption, and thickness swelling as well as reducing hardness, impact strength, and pyrolysis temperature. The degree of degradation of the fiber and matrix is positively correlated with that of the fiber-matrix interface interaction. The analysis of the experimental phenomenon indicates that protecting the fiber-matrix interface maintains the durability of WPC materials.

Superparamagnetic wood‐polypropylene nanocomposite made using magnetic wood flour with a nanoparticle‐free surface

“…Using FFMWF filler instead of LFMWF resulted in a poor MWF‐polymer interface, leading to more microgaps in the MWPNC structure. There is a significant correlation between the water uptake of the WPC samples and the increase in structural microgaps 56,57 . On the other hand, increasing the number and size of structural microgaps seems to reduce the swelling effect of the filler particles on the thickness swelling of the WPC.…”

“…With increasing immersion time, the index value TS/WU gradually decreases to values below one, indicating a decrease in the thickness swelling of the samples while water uptake remains constant (Figure 5e). The filler content and the structural microgaps seem to influence the water uptake and the thickness swelling of the WPC specimens 2,56,57 . The maximum swelling of the filler particles occurs when the water absorption reaches the fiber saturation point (FSP ≈ 25%–30% MC) 1,58 .…”

“…There is a significant correlation between the water uptake of the WPC samples and the increase in structural microgaps. 56,57 On the other hand, increasing the number and size of structural microgaps seems to reduce the swelling effect of the filler particles on the thickness swelling of the WPC. After water uptake, a part of the thickness swelling of the filler particles is spent to fill the microgap and structural discontinuity at the filler-matrix interface before affecting the thickness of the MWPNC sample.…”

“…The filler content and the structural microgaps seem to influence the water uptake and the thickness swelling of the WPC specimens. 2,56,57 The maximum swelling of the filler particles occurs when the water absorption reaches the fiber saturation point (FSP ≈ 25%-30% MC). 1,58 Using FFMWF filler instead of LFMWF resulted in a poor MWF-polymer interface, leading to more microgaps in the MWPNC structure.…”

Aging and tribological behavior of styrene butadiene rubber conveyor belts under combined seawater dry-wet conditions

“…The soak temperature, soak time, drying temperature, and drying time were selected as the key factors for the orthogonal design of L9 (34) based on a single-factor test. Base on the time-temperature equivalence principle, the maximum temperature of the tropical sea surface (30 °C) and land surface temperature in summer (70 °C) were selected as the lower limits of the seawater and drying temperatures [15], respectively , as summarized in table 3. One seawater-dry-wet cycle was divided into two steps: (i) immersion in seawater for a given time and temperature, and; (ii) drying in an oven for a given time and temperature.…”