The problem of white pollution caused by waste agricultural mulch film (WAMF) has a long history and has brought great damage to the soil and ecological environment. The recycled WAMF has no ...processing performance because it is doped with a large amount of cotton straw and soil inorganic particles. In this study, it was reported for the first time that high‐quality and efficient recovery of WAMF was carried out by means of solid‐state shear milling (S3M) technology. After the pretreatment of S3M, the recycled WAMF is transformed into an active composite powder with a particle size of microns, which regains certain processing performance. Then we prepared a composite material similar to WPC (wood‐plastic composite) by using the composite powder. It was found that under the action of strong three‐dimensional shear force, the phase domain size of the composite decreased significantly, and the compatibility of each component improved. The macroscopic performance was that the tensile strength was increased by 65% and the bending strength was increased by 74%, reaching 8.30 and 17 MPa, respectively. The 24‐h water absorption of this composite decreased by 13%. More importantly, the thermal stability was not significantly reduced during the milling process. This process does not require sorting, cleaning, or other operations, which can greatly simplify the process flow and improve recovery efficiency. It provides an effective solution to the problem of white pollution caused by WAMF.
Preparation of WPC/SIP composite by S3M technology and the effect of milling times on the mechanical properties of composites.
Wood–plastic composites represent a growing class of materials used by the residential construction industry and the furniture industry. For some applications in these industries, the fire ...performance of the material must be known, and in some cases improved. However, the fire performance of wood–plastic composites is not well understood, and there is little information regarding the effectiveness of various fire retardants in the public domain. We used oxygen index and cone calorimeter tests to characterize the fire performance of wood flour–polyethylene composites, and compared the results with unfilled polyethylene and solid wood. We then evaluated the effect of five additive-type fire retardants on fire performance. Generally, magnesium hydroxide and ammonium polyphosphate improved the fire performance of WPCs the most while a bromine-based fire retardant and zinc borate improved fire performance the least.
This study investigates the effect of removing magnetic nanoparticles from the outer surface of magnetic wood flour (MWF) particles as a filler phase on the microstructural, physical, and mechanical ...properties of the prepared MWF‐polypropylene nanocomposites. For producing MWF with a surface free of magnetic nanoparticles (called LFMWF), in contrast to the commonly produced MWF (called FFMWF), magnetic wood chips were first prepared and then milled. No significant changes were observed in the tensile and flexural strength of the composite specimens prepared with the LFMWF filler instead of the FFMWF. The samples containing the LFMWF filler showed lower water uptake and higher thickness swelling after 400 h of immersion. The coupling agent's effect on improving the mechanical properties of the specimens was more pronounced than its effect on the water uptake and thickness swelling of the specimens. The saturation magnetization of LFMWF was about 4.3 emu/g, while that of FFMWF was 0.94 emu/g. After melt compounding the MWFs with the polymer matrix, the saturation magnetization decreased; this decrease was about 9.9% higher for the FFMWF‐containing magnetic nanocomposites than for the LFMWF‐containing ones.
Composite materials were made from
Pinus radiata wood flour, and recycled and virgin polyolefin, mainly high density polyethylene (HDPE) and polypropylene (PP) polymer, by using hot-pressing ...moulding. Long-term water absorption and thickness swelling (TS) kinetics of the composites was investigated with water immersion. It was found that the water absorption and TS increase with wood content and water immersion time before an equilibrium condition was reached. Composites made from the recycled plastics show comparable results as those made of the virgin plastics. It is interesting to find that the water absorption and TS can be reduced significantly with incorporation of a coupling agent (maleated polypropylene) in the composite formulation. Microstructures of the composites were examined to understand the mechanisms for the wood–plastic interaction which affects the water absorption and thickness swelling. Further studies were conducted to model the water diffusion and thickness swelling of the composites. Diffusion coefficients and swelling rate parameters in the models were obtained by fitting the model predictions with the experimental data.
Wood plastic composites (WPCs) were produced from thermally treated beech (Fagus orientalis L.) wood and polypropylene (PP) polymer with coupling agent, by using injection molding. The wood chips ...were thermally treated for 30 or 120min at three different temperatures (120°C, 150°C, or 180°C) under saturated steam in a digester and then grounded (40-mesh size) by wood mill. Long-term water absorption kinetics of the composites were investigated with water immersion test. It was found that the water absorption decreased with increasing severity of the thermal-treatment and water immersion time as compared to the control composites. Furthermore, the composites produced with wood treated at 180°C for 120min exhibited the least water absorption. Microstructures of the composites were examined by SEM analysis to understand the mechanisms for the wood–plastic interaction which affected the water absorption. Further studies were conducted to model the water diffusion of the composites. Diffusion coefficient parameter in the models was obtained by fitting the model predictions with the experimental data. Water absorption of the studied composites was proved to follow the kinetics of a Fickian diffusion process.
•Chinese Fir residue was used as reinforcement in addition to LDPE matrix.•MPOE, OMMT and their combinations were used as compatibilizers.•MPOE as a compatibilizer improve the impact strength.•The ...combination of MPOE and OMMT significantly improved the tensile strength.
The challenge to improve the interface in wood-plastic composite (WPC) has continued to remain a major setback in the field of wood technology. In this work, a novel hybrid compatibilizer system was developed. Chinese fir (Cunninghamia lanceolata) waste and low-density polyethylene were used as a reinforcing lignocellulosic material and matrix, respectively. Maleic anhydride grafted polyethylene octene elastomer (MPOE), octadecyl organically modified montmorillonite (OMMT) and their combinations were used as compatibilizers. The as-produced composites were characterized for their mechanical and physical properties using the SEM, FTIR, and mechanical testing. The result shows a significant increase in tensile strength of about 41.46 % when a mixture of MPOE and OMMT were used as compatibilizers. Moreover, the addition of MPOE led to the improvement of the impact strength by 26.89 %. Thus, the utilization of both compatibilizers offers an efficient route to improve the interaction and mechanical properties of WPC.
In this study, it is aimed to produce wood plastic composite material with eggshell additives and to investigate the mechanical properties of these materials. Mechanical properties such as tensile ...strength and modulus of elasticity, elongation at break, flexural strength and modulus of elasticity and impact resistance of new materials produced by adding eggshell to wood plastic composite at different rates were investigated. It was determined that tensile strength values gradually decreased due to the increase in the amount of eggshell in the composites produced. The modulus of elasticity of the composite material in tensile strength increases with the increase in the amount of eggshell in the mixture. With the increase of the eggshell ratio used, the elongation values of the plastic composite at break are reduced. The eggshell material used in wood plastic composite reduces the bending strength of the material. The eggshell reduces the modulus of elasticity of the composite material in bending. The eggshell composite material did not cause a significant change in impact resistance.
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•Catalytic pyrolysis of wood plastic composite was investigated.•In-situ catalytic pyrolysis produce the larger amount of aromatics than ex-situ reaction.•Aromatics formation was ...hindered by the use of small pore HZSM-5.•Coke formation was increased over large pore HY.
The catalytic pyrolysis of commercial wood plastic composite (WPC) over microporous catalysts was investigated by thermogravimetric (TG) analysis and tandem micro reactor-gas chromatography/mass spectrometry (TMR-GC/MS). The non-isothermal TG analysis results showed that the decomposition temperatures of polyethylene and polypropylene in the WPC were shifted to lower temperatures by the use of catalysts, from 484 °C to 440 °C over HY(5.1), 457 °C over HBeta(25), and 469 °C over HZSM-5. TMR-GC/MS indicated that the formation efficiency of aromatic hydrocarbons during the catalytic pyrolysis of WPC was affected not only by the catalyst properties, but also by the contact mode between the WPC and catalyst. The in-situ catalytic pyrolysis of WPC showed a higher aromatic formation efficiency than the ex-situ reaction because of the sufficient likelihood of a reaction between the reactant molecules and catalysts during the in-situ reaction. Among the catalysts, HBeta produced the largest amount of aromatics followed by HZSM-5 and HY. Diffusion hindering of the reactant molecules to the small pores of HZSM-5 and the large amount of coke inside the large pores of HY were the main reasons for the lower aromatic formation efficiency over HZSM-5 and HY than over HBeta. Sequential catalytic TMR-GC/MS showed that the increased diffusion hindering effect caused by coke accumulation is the main limitation on the use of HZSM-5. Mesoporous HZSM-5 may be a potential way of overcoming the limitation of the catalysts used in this study.
•Two kinds of silane coupling agents (r-aminopropyl triethoxy silane, KH550; and trimethoxy vinyl silane, A171) and dicumyl peroxide were used to bond the wood fiber/high-density polyethylene ...(WF/HDPE) composite and wood veneer.•Samples treated with A171 had higher bonding strength than those treated with KH550.•The greater the volume of wood fiber in the WF/HDPE, the poorer the bonding strength of the veneer and the lower its water resistance.
Because of the smooth, dense, and nonpolar surface of wood-plastic composites (WPCs), it is challenging to form an efficient bonding interface between the WPC and the material of the wood veneer by using traditional adhesives. In this study, two kinds of silane coupling agents (r-aminopropyl triethoxy silane, production number KH550; and trimethoxy vinyl silane, production number A171) and dicumyl peroxide were used to improve the bond between the wood fiber/high-density polyethylene (WF/HDPE) composite and the wood veneer. The attenuated total reflection-Fourier transform infrared spectroscopy curve shows that the two kinds of silane coupling agents were grafted to the surface of the wood veneer, and the contact angle between distilled water and the veneer surface increased from 46° to greater than 120° after treatment. The bonding strength between the treated veneer and the WF/HDPE composite was significantly enhanced, and samples treated with A171 had higher bonding strength than those treated with KH550. The greater the volume of wood fiber in the WF/HDPE, the poorer the bonding strength of the veneer and the lower its water resistance. Images from a scanning electron microscope show that the silane coupling agent A171 can induce a denser interface between the wood veneer and the WF/HDPE composite.
•Novel ammonium polyphosphate-based flame retardant with anti-aging function.•Caffeic acid enhanced flame-retardant efficiency of ammonium polyphosphate.•Flame-retarded and anti-aging wood plastic ...composite.
Wood plastic composites (WPCs) are facing fire hazard and aging when they are used as building materials. In current work, ammonium polyphosphate-based flame retardant decorated with caffeic acid (MAPP-CA) was prepared by the two-step reaction of ammonium polyphosphate (APP), ethylenediamine, and caffeic acid. The chemical structure of MAPP-CA was characterized by different measurements. When the loading amount of MAPP-CA was 25 wt% in WPC, WPC/MAPP-CA25 sample passed the UL-94 V-0 rating and limited oxygen index (LOI) value reached 26.5%. Compared with WPC, WPC/MAPP-CA25 showed significantly lower heat release and smoke release. Besides, MAPP-CA improved the anti-aging property of WPC. According to oxidation induction time (OIT) result of WPC, WPC/APP25 and WPC/MAPP-CA25. The OIT of WPC/MAPP-CA25 is much longer than that of WPC (17.8 min) and WPC/APP25 (36.8 min), about 7.4 and 3.6 times of the latter two, respectively. Further, the retention ratios of mechanical properties showed that the retention in flexural strength and notched impact strength for WPC/MAPP-CA25 is superior to that of WPC/APP25 and WPC after aging at 120 ℃. Flame-retardant and anti-aging mechanisms of MAPP-CA were investigated in detail. This work opens a new route for upgrading traditional flame retardant.
