Co-reporter:Lichao Sun, Qinglin Wu, Yanjun Xie, Fengqiang Wang and Qingwen Wang
RSC Advances 2016 vol. 6(Issue 17) pp:13890-13897
Publication Date(Web):15 Jan 2016
DOI:10.1039/C5RA23262G
Single and multi-layer structured wood fiber and polypropylene composites (WPPCs) filled with magnesium hydroxide (MH), expandable graphite (EG), or ammonium polyphosphate (APP) were prepared. Thermal degradation and flammability properties of the composites were determined by thermogravimetric analysis and cone calorimetry. Results of both thermogravimetry and cone calorimetry indicated that single layer WPPC filled with MH, EG or APP reduced the HRR and THR, and increased the mass of residue compared with the control sample. The results on fire performance of multilayer structured WPPC indicated that the improvement or depravation on fire retardance properties of the WPPC depends on the different mechanism of fire retardants. EG showed the best fire retardance properties in the multilayer structured WPPC system compared to MH and APP. Furthermore, the use of the EG in the cap layer greatly reduced the heat and smoke release of the overall multilayer structured composites compared to single layer fire retardant WPPC. The residues of combusted WPPC after the cone calorimetry test were characterized by scanning electron microscopy (SEM), the results further revealed that the presence of EG in the cap layer could protect the underlying substrate from degradation and char formation.
Co-reporter:Tian Liu;Yanjun Xie ;Qiliang Fu
Polymer Composites 2016 Volume 37( Issue 2) pp:379-384
Publication Date(Web):
DOI:10.1002/pc.23190
Enzymatic hydrolysis lignin (EHL) from ethanol production was used as an additive to incorporate in the wood flour/high-density polyethylene (HDPE) composite during the melt extrusion, and the incorporating effects on the mechanical and rheological properties of the resulting composites were investigated. The addition of EHL caused an improvement in both the tensile strength and impact strength, and a reduction in the complex viscosity of the composites as evidenced by the rotational rheometry, which suggests an increased flowability of the composite melt due to incorporation of EHL. The water absorption and swelling of the composites decreased with increasing EHL content during water immersion test. The scanning electron microscopy micrographs of EHL incorporated wood flour/high-density polyethylene composites showed a homogeneous dispersion of wood flour and EHL in the HDPE matrix. POLYM. COMPOS., 37:379–384, 2016. © 2014 Society of Plastics Engineers
Co-reporter:Xiaona Lin, Zhijun Zhang, Jianping Sun, Wenjun Guo, Qingwen Wang
Journal of Analytical and Applied Pyrolysis 2015 Volume 116() pp:223-230
Publication Date(Web):November 2015
DOI:10.1016/j.jaap.2015.09.007
•Waste WPC was converted into reusable hydrocarbons by catalytic pyrolysis.•Hydrocarbon selectivity was strongly influenced by reaction conditions in pyrolysis.•Phosphorus-modified HZSM-5 favored light aliphatics (C4-C12) formation.•Aliphatics selectivity increased with the increasing P content in modified HZSM-5.ZSM-5 zeolite is an efficient catalyst for both biomass deoxygenation and polyolefins cracking in pyrolysis process. In this study, wood–plastic composite (WPC), composed mainly of woody materials and thermoplastic polymers, was pyrolyzed using Py-GC/MS over phosphorus-modified HZSM-5 (P-HZSM-5) with varying P loadings (from 0 to 10 wt.%). The catalysts were prepared by wet impregnation method and characterized by XRF, XRD and NH3-TPD. The effects of pyrolysis temperature, time, heating rate, catalyst to WPC ratio and P loadings on the hydrocarbon distribution of WPC pyrolysis were studied. Pyrolysis conditions have significant effects on hydrocarbon distribution. Parent HZSM-5 facilitated aromatics formation, while P-HZSM-5 favored the formation of light aliphatic hydrocarbons (C4-C12). The yields of C4-C12 increased first with rising pyrolysis temperature from 450 to 550 °C, then decreased over 550 °C. Similarly, C4-C12 yields increased during the pyrolysis time from 15 to 30 s and decreased with the further prolonged time. A low heating rate (0.002 °C/ms) favored the formation of light aliphatic hydrocarbons, while high heating rates (>0.2 °C/ms) favored the formation of aromatics. Increasing catalyst to WPC ratio augmented aromatic selectivity. Hydrocarbon distribution strongly depended on the catalyst’s acidity, adjusted by varying P loading in P-HZSM-5. The highest yield of C4-C12 was obtained while using P-HZSM-5 with P loading of 3.5 wt.%.
Co-reporter:Rongxian Ou, Yanjun Xie, Michael P. Wolcott, Feipin Yuan, Qingwen Wang
Composites Science and Technology 2014 Volume 93() pp:68-75
Publication Date(Web):18 March 2014
DOI:10.1016/j.compscitech.2014.01.001
This study investigated the effect of wood cell wall composition on the rheological properties of wood particle/high density polyethylene (HDPE) blends. Four types of wood particle with different compositions were prepared: native wood flour (WF), hemicellulose-removed particle (HR), holocellulose (HC), and α-cellulose (αC). The particles were characterized in terms of functional groups, crystallinity, particle size, and morphology. Wood particle/HDPE composite formulations were melt-blended using a twin-screw extruder and the rheological properties of the blends were characterized using a Haake microcompounder, torque rheometer, capillary rheometer, and rotational rheometer. Results show that removal of lignin and/or hemicelluloses changed the crystallinity and microstructure of cell walls. These changes in cell wall composition and morphology altered the melt torque, shear stress, viscosity, and storage and loss moduli. Specifically, the melts viscosity decreased as αC/HDPE > HR/HDPE > WF/HDPE > HC/HDPE. This demonstrates that the composition of cell walls substantially affect the rheological behavior of wood particle/HDPE composites.
Co-reporter:Rongxian Ou;Yanjun Xie;Shujuan Sui;Michael P. Wolcott
Journal of Applied Polymer Science 2014 Volume 131( Issue 11) pp:
Publication Date(Web):
DOI:10.1002/app.40331
ABSTRACT
This study investigated the effect of removal of wood cell wall composition on thermal, crystallization, and dynamic rheological behavior of the resulting high density polyethylene (HDPE) composites. Four types of wood particle (WP) with different compositions: native wood flour (WF), hemicellulose-removed wood particle (HR), lignin-removed wood particle (holocellulose, HC), and both hemicellulose and lignin removed particle (α-cellulose, αC) were prepared and compounded with HDPE using extruder, both with and without maleated polyethylene (MAPE). Results show that removal of the hemicellulose improved the thermal stability of composites, while removal of the lignin facilitated thermal decomposition. WPs acted as nucleating agents and facilitated the process of crystallization, thereby increasing the crystallization temperature and degree of crystallinity. The crystallization nucleation and growth rate of αC and HR based composites without MAPE decreased, as compared with WF based one. Composite melts with and without MAPE exhibited a decreasing order of storage modulus, loss modulus, and complex viscosity as αC > WF > HR > HC and αC > HR > WF > HC, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40331.
Co-reporter:Rongxian Ou, Yanjun Xie, Qingwen Wang, Shujuan Sui, Michael P. Wolcott
Composites Part A: Applied Science and Manufacturing 2014 Volume 61() pp:134-140
Publication Date(Web):June 2014
DOI:10.1016/j.compositesa.2014.02.017
Wood flour was treated with an ionic liquid, 1-(2-hydroxyethyl)-3-methylimidazolium chloride ([Hemim]Cl), to various weight percent gains. The treating effects on the rheological properties of the resulting wood flour/high density polyethylene (HDPE) blends were investigated using a Haake microcompounder and torque-, capillary-, and rotational-rheometer, respectively. Treatment with [Hemim]Cl caused a decrease in the crystallinity and an improvement in the thermoplasticity of wood flour. At low processing speeds, the melt torque and viscosity increased with increasing [Hemim]Cl content; while at high speed, they decreased or remained the same. [Hemim]Cl can broaden the processing window of wood flour/HDPE composites with stable flow and smooth product surfaces. The dynamic rheological results show that storage and loss moduli and complex viscosity of the composite melts increased with increasing [Hemim]Cl content.
Co-reporter:Tian Liu;Yanjun Xie;Sunyoung Lee;Qinglin Wu
Polymer Bulletin 2014 Volume 71( Issue 3) pp:685-703
Publication Date(Web):2014 March
DOI:10.1007/s00289-013-1086-x
Microfibrillar composites from high-density polyethylene (HDPE-75 wt%) and polyamide-6 (PA6-25 wt%) were made through a reactive extrusion at the processing temperature of PA6 in combination with hot stretching to form microfibrillar composites, and injection molding at the melt temperature of HDPE to form final composites. The scanning electron microscope observations demonstrated the formation of the PA6 microfibers during extrusion. Incorporation of PA6 microfibers led to an improvement in both flexural and tensile properties as compared to the neat HDPE. Use of ethylene–glycidyl methacrylate copolymers (E-GMA) in the composites gave the highest tensile modulus, while ethylene, butyl acrylate and maleic anhydride terpolymer (E-BA-MA) led to the highest tensile strength and elongation. The maleic anhydride grafted polyethylene (MAPE) was the most efficient among three coupling agents in improving impact strength. With the addition of 5 wt% E-GMA, E-BA-MA and MAPE, the HDPE/PA6 composites exhibited an improvement of 87, 116, and 387 %, respectively, compared to the uncoupled controls. The PA6 microfibers exhibited a regular orientation along the stretching direction in the presence of 2.5 wt% coupling agents; increasing the loading level of coupling agents caused a reduction in the diameter of PA6 microfibers. FT-IR analyses showed the reactions between PA6 and the coupling agents used.
Co-reporter:Rongxian Ou, Yanjun Xie, Michael P. Wolcott, Shujuan Sui, Qingwen Wang
Materials & Design 2014 58() pp: 339-345
Publication Date(Web):
DOI:10.1016/j.matdes.2014.02.018
Co-reporter:Y.H. Zhang;D.M. Zhao;Z. Sang;L.J. Sun;Q.W. Wang
Polymer Composites 2013 Volume 34( Issue 5) pp:757-762
Publication Date(Web):
DOI:10.1002/pc.22487
Abstract
In this study, slow release materials–poly(lactide-co-glycolide) (PLGA) ultrafine fiber mats containing different ketoconazole (KCZ) contents were prepared and their release behaviors were investigated in vitro. PLGA/KCZ ultrafine fiber mats were prepared via electrospinning and characterized by means of scanning electron microscope, Fourier transform infrared, X-ray diffraction (XRD), and thermal gravimetric analysis. The slow release properties of PLGA/KCZ fiber mats in vitro were studied by measuring the concentrations of KCZ dissolved in the phosphate buffered solution (pH = 4.5) at a programmed time. Results indicated that KCZ could be dispersed in PLGA very well in a wide range of KCZ content from 10 to 100% with respect to PLGA. Most KCZ in PLGA fibers were physically dispersed. The thermal decomposition temperature of PLGA was lowered due to the incorporation of KCZ. With increased drug concentration, the release amount would increase in unit time. The two-stage releases would be sustained to achieve the effective utilization of KCZ. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Co-reporter:Yiqun Fang, Qingwen Wang, Chuigen Guo, Yongming Song, Paul A. Cooper
Journal of Analytical and Applied Pyrolysis 2013 100() pp: 230-236
Publication Date(Web):
DOI:10.1016/j.jaap.2012.12.028
Co-reporter:Wei-jun Yang;Yan-jun Xie;Hai-gang Wang;Bao-yu Liu
Journal of Forestry Research 2013 Volume 24( Issue 1) pp:143-147
Publication Date(Web):2013 March
DOI:10.1007/s11676-013-0334-0
Wood plastic composite (WPC) of wood flour (WF), high density polyethylene (HDPE), maleic anhydride-grafted polyethylene (MAPE) and lubricant was prepared by extrusion, and then exposed to different temperatures to evaluate the effects of freezing and thermal treatment on its dimensional and mechanical properties. At elevated temperatures, WPC expanded rapidly initially, and then contracted slowly until reaching an equilibrium state. Treatment at 52°C and relative humidity of 50% for 16 days improved the mechanical properties of WPC: flexure, tensile strength, and izod unnotched impact strength increased by 8%, 10% and 15%, respectively. Wide-angle X-ray diffraction (XRD) tests showed that the degree of crystalization of HDPE in WPC declined with increasing treatment temperature.
Co-reporter:Rongxian Ou;Yanjun Xie;Chuigen Guo
Journal of Applied Polymer Science 2012 Volume 126( Issue S1) pp:E2-E9
Publication Date(Web):
DOI:10.1002/app.36425
Abstract
Kevlar fiber [KF; poly(p-phenylene terephthalamide)] can be used as a reinforcing element to improve the mechanical properties of the resulting wood thermoplastic composites. This study was devised to investigate the effects of incorporation of KF on the isothermal crystallization kinetics of high-density polyethylene (HDPE) in the resulting composites using differential scanning calorimetry. Avrami model was applied to describe the isothermal crystallization process, and the fold surface-free energy was calculated according to the Hoffman–Lauritzen theory. Comparative study of neat HDPE, wood flour/HDPE composite (WPC), virgin KF-reinforced WPC (KFWPC), and grafted Kevlar fiber (GKF)-reinforced WPC (GKFWPC) showed that the overall crystallization rate, the activation energy, the equilibrium melting temperature, and the fold surface-free energy of the WPC were apparently changed due to the addition of KF; the crystallizability exhibited an order of KFWPC > GKFWPC > HDPE > WPC. The incorporation of virgin KF may cause the heterogeneous nucleation to induce a change in the crystal growth of HDPE from the tridimensional to bidimensional or to the mixed patterns. Avrami exponent values of the composites decreased with time, confirming the change of crystallization behavior. This study demonstrates that both the KF and GKF can act as nucleating agents to improve the crystallization rate of HDPE. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Zewen Li;Hua Gao
Journal of Applied Polymer Science 2012 Volume 124( Issue 6) pp:5247-5253
Publication Date(Web):
DOI:10.1002/app.34233
Abstract
Highly filled wood flour/recycled high density polyethylene (WF/RHDPE) composites were directly prepared by in situ reactive extrusion using a twin-screw/single-screw extruder system. The effects of dicumyl peroxide (DCP) content on extrusion pressure, rheological behavior, mechanical properties, fractured surface morphology of the composites, and melting temperature of RHDPE in the composites were investigated. The extrusion pressure and torque of WF/RHDPE composite melt increased with DCP content. Mechanical property tests and scanning electron microscopy analysis results confirmed that the interfacial interaction of the composites was improved by in situ reaction. The composites show lower melting peak temperature (Tm) than RHDPE. The cooling in profile extrusion shortened the crystallization time, resulting in decrease of crystalline order of RHDPE in the composites. There are no noticeable changes of Tm values with increasing DCP content. Comparative study on composites with maleic anhydride grafted polyethylene as compatibilizer demonstrated that mechanochemical treatment with DCP and maleic anhydride was an effective method to improve interfacial adhesion for WF/RHDPE composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Hua Du;Weihong Wang;Shujuan Sui;Yongming Song
Journal of Applied Polymer Science 2012 Volume 126( Issue 3) pp:906-915
Publication Date(Web):
DOI:10.1002/app.36558
Abstract
In China, rice-hull powder is widely used as a fiber component to reinforce polymers because of its ready availability and lower cost compared to wood fibers. However, an issue concerning these composites is their weathering durability. In this study, the effects of two ultraviolet absorbers (UVAs), UV-326 and UV-531, on the durability of rice-hull/high-density polyethylene (HDPE) composites were evaluated after the samples were exposed to UV-accelerated weathering tests for up to 2000 h. All of the samples showed significant fading and color changes in exposed areas. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to detect surface chemical changes. The results indicate that surface oxidation commenced immediately within the first 500 h of exposure for all of the samples. However, the control rice-hull/HDPE composites underwent a greater degree of oxidation than those with the UVAs. Scanning electron microscopy revealed that the rice-hull/HDPE composites degraded significantly upon accelerated UV aging, with dense cracking on the exposed surface. The UVAs provided effective protection for the rice-hull/HDPE composites, and UV-326 had a more positive effect on the color stability than UV-531. The results reported herein serve to enhance our understanding of the efficiency of UV stabilizers in the protection of rice-hull/HDPE composites against UV radiation, with a view toward improving their formulation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Rongxian Ou;Yanjun Xie;Xiaoping Shen;Feipin Yuan
Journal of Materials Science 2012 Volume 47( Issue 16) pp:5978-5986
Publication Date(Web):2012 August
DOI:10.1007/s10853-012-6502-3
This study investigated the effects of an ionic liquid, 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), as a doping salt, on the properties of resulting solid biopolymer electrolytes (SPEs) based on all-cellulose composites. The conductivity of the resulting SPEs increased with the [Bmim]Cl loading. Both incubation time and chemical loading affected the tensile properties of the SPEs. The SPEs prepared under the optimum processing conditions exhibited a tensile strength and conductivity of 18.2 MPa and 1.28 × 10−3 S cm−1, respectively, when tested at room temperature. FTIR and XPS spectra showed that the concentration of [Bmim]Cl in the SPEs was greater at the surface than at the interior. Treatment with [Bmim]Cl resulted in a decrease in the crystallinity and thermal stability of the SPEs as evidenced by XRD and TGA analyses. This study demonstrates that treatment of cellulosic materials with the ionic liquid [Bmim]Cl can create biomass-based SPEs with high conductivity, improved mechanical properties, good thermal stability and easy processability.
Co-reporter:Hua Gao, Yanjun Xie, Rongxian Ou, Qingwen Wang
Composites Part A: Applied Science and Manufacturing 2012 Volume 43(Issue 1) pp:150-157
Publication Date(Web):January 2012
DOI:10.1016/j.compositesa.2011.10.001
In the presented study, polypropylene (PP) and high density polyethylene (PE) were blended at the ratios of 80/20 and 20/80 to simulate recycled waste thermoplastic mixtures. The effects of in situ grafting of PP/PE blends with maleic anhydride through the extruder on the mechanical and rheological properties of resulting wood/plastic composites were investigated. Different ratios of PP and PE in the blends created distinct properties in the resulting composites. Grafting of PP and PE blends improved the tensile and flexure properties of the resulting composites. The composites exhibited a reduced water uptake and resultant dimensional swelling due to grafting with maleic anhydride. Grafting of the blends also considerably improved the interfacial bonding and enhanced the dispersion of wood in the matrix, as evidenced by rheological analysis and scanning electron microscopy.
Co-reporter:Hua Du;Weihong Wang;Zhengming Zhang;Shujuan Sui;Yanhua Zhang
Journal of Applied Polymer Science 2010 Volume 118( Issue 2) pp:1068-1076
Publication Date(Web):
DOI:10.1002/app.32430
Abstract
The effects of different color pigments on the durability of wood-flour/high-density polyethylene composites (WF/HDPE) were evaluated by UV-accelerated weathering tests. WF/HDPE composites were dyed using three different color inorganic pigments, which were added at 2% based on the weight of the composite. Samples were weathered in Q-panel UV aging equipment for 1500 h. All samples showed significant fading and color changes in exposed areas. Changes in surface chemistry were studied using spectroscopic techniques. X-ray photoelectron spectroscopy (XPS) was used to verify the occurrence of surface oxidation. Changes in carbonyl groups (CO), PE crystallinity, cellulose CO, and lignin aromatic CC were detected by Fourier transform infrared (FTIR) spectroscopy. The results indicate that surface oxidation occurred immediately within exposure 250 h for all samples; the surface of the control WF/HDPE composites was oxidized to a greater extent than that of the dyed WF/HDPE. This suggests that the addition of pigments to the WF/HDPE composites results in less weather-related damage. The surface configuration observed by scanning electron microscopy revealed that WF/HDPE composites degraded significantly on accelerated UV aging, with dense cracking apparent on the exposed surface. Carbon black had a more positive effect on color stability than the other pigments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Yong-ming Song;Qing-wen Wang;Guang-ping Han
Journal of Forestry Research 2010 Volume 21( Issue 3) pp:373-378
Publication Date(Web):2010 September
DOI:10.1007/s11676-010-0084-1
The effect of maleic anhydride grafted styrene-ethylene- butylene-styrene block copolymer (SEBS-g-MAH) and in-situ grafting MAH on mechanical, dynamic mechanical properties of wood flour/recycled plastic blends composites was investigated. Recycled plastic polypropylene (PP), high-density polyethylene (HDPE) and polystyrene (PS), were mixed with wood flour in a high speed blender and then extruded by a twin/single screw tandem extruder system to form wood flour/recycled plastic blends composites. Results show that the impact properties of the composites were improved more significantly by using SEBS-g-MAH compatibilizer than by using the mixtures of MAH and DCP via reactive blending in situ. However, contrary results were observed on the tensile and flexural properties of the corresponding composites. In General, the mechanical properties of composites made from recycled plastic blends were inferior to those made from virgin plastic blends, especially in elongation break. The morphological study verified that the interfacial adhesion or the compatibility of plastic blends with wood flour was improved by adding SEBS-g-MAH or in-situ grafting MAH. A better interfacial bonding between PP, HDPE, PS and wood flour was obtained by in-situ grafting MAH than the addition of SEBS-g-MAH. In-situ grafting MAH can be considered as a potential way of increasing the interfacial compatibility between plastic blends and wood flour. The storage modulus and damping factor of composites were also characterized through dynamic mechanical analysis (DMA).
Co-reporter:Zheng-ming Zhang;Hua Du;Wei-hong Wang;Qing-wen Wang
Journal of Forestry Research 2010 Volume 21( Issue 1) pp:59-62
Publication Date(Web):2010 March
DOI:10.1007/s11676-010-0009-z
Four kinds of iron oxide pigments were added into wood-fiber/high-density-polyethylene composites (WF/HDPE) at three different concentrations, to determine the effects of pigments on the changes in the color and mechanical properties of the composites before and after UV accelerated weathering. HDPE, wood fibers, pigments and other processing additives were dry-mixed in a high-speed mixer. The mixtures were extruded by two-step extrusion process with a self-designed twin-screw/single-screw extruder system. Color of the samples was determined according to CIE 1976 L*a*b* system by a spectrophotometer and the bending properties were tested to evaluate the mechanical properties before and after accelerated UV weathering. The result shows that the modulus of elasticity of WF/HDPE did not obviously changed after incorporating with the pigments, but the bending strength increased. After accelerated aging for 2000 h, both color and mechanical properties significantly changed. Iron oxide red and black performed better than the other two pigments, and the pigments dosage of 2.28% in the composites is favourable.
Co-reporter:Chui Gen Guo;Qing Wen Wang
Journal of Applied Polymer Science 2008 Volume 109( Issue 5) pp:3080-3086
Publication Date(Web):
DOI:10.1002/app.27800
Abstract
In this article, the effects of m-isopropenyl-α,α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-PP) on the interfacial interaction of wood-flour/polypropylene (WF/PP) were investigated by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry, dynamic rheological analysis, and mechanical properties tests. The experimental results demonstrated that m-TMI-PP greatly improved the interfacial interaction between WF and PP. According to the DSC results, m-TMI-PP made the crystallization temperature and the crystallization degree of PP in WF/m-TMI-PP/PP decrease when compared with WF/PP composite without m-TMI-PP, but it was still higher than pure PP. These results demonstrated that WF presented the nucleate effect for the crystallization of PP and m-TMI-PP improved the interfacial adhesive, which restrained the mobility of PP chain. The rheological analysis indicated that the complex viscosity, storage, and loss modular of WF/PP composite increased, and the tan δ decreased with the addition of m-TMI-PP. This was attributed to the strong improvement effects of m-TMI-PP on the interfacial interaction of the composites, and was further confirmed by the mechanical properties tests and SEM analysis of the composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Fengqiang Wang;Zhijun Zhang;Jiayin Tang
Frontiers of Forestry in China 2008 Volume 3( Issue 4) pp:487-492
Publication Date(Web):2008 December
DOI:10.1007/s11461-008-0075-y
An intumescent waterborne amino-resin fire-retardant coating for wood (C) was synthesized and its fire-retardant and smoke-suppressant properties were investigated. The main film-builder of C was urea-formaldehyde resin blended with polyvinyl acetate resin. The intumescent fire-retardant system of C consisted of guanylurea phosphate (GUP), ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL). Specimens of plywood painted, respectively, with a commercial intumescent fire-retardant coating (A), a synthesized coating (C), and the main film-builder of coating C (B), as well as an unpainted plywood (S-JHB), were analyzed by cone calorimetry (CONE). The results show a marked decrease in the heat release rate (HRR) and the total heat release (THR), an increased mass of residual char (Mass), a marked postponement in time to ignition (TTI) and a reduced carbon monoxide production rate (PCO). The smoke production rate (SPR) and total smoke production (TSP) of the plywood painted with coating C were observed with the CONE test. The overall fire-retardant and smoke-suppressant performance of the synthesized coating C was much better than that of the commercial coating A. The thermo-gravimetric analysis (TGA) results of coating C and its film-builder B indicated that the thermal degradation process of B was slowed down by the addition of the intumescent fire-retardant system; the increase in the amount of charring of coating C was considerable.
Co-reporter:Hua Gao;Yong-ming Song;Qing-wen Wang;Zhen Han
Journal of Forestry Research 2008 Volume 19( Issue 4) pp:315-318
Publication Date(Web):2008 December
DOI:10.1007/s11676-008-0057-9
For evaluation of the rheological and mechanical properties of highly filled wood plastic composites (WPCs), polypropylene/polyethylene (PP/PE) blends were grafted with maleic anhydride (MAH) to enhance the interfacial adhesion between wood fiber and matrix. WPCs were prepared from wood fiber up to 60 wt.% and modified PP/PE was blended by extrusion. The rheological properties were studied by using dynamic measurement. According to the strain sweep test, the linear viscoelastic region of composites in the melt was determined. The result showed that the storage modulus was independent of the strain at low strain region (<0.1%). The frequency sweep results indicated that all composites exhibited shear thinning behavior, and both the storage modulus and complex viscosity of MAH modified composites were decreased comparing to those unmodified. Flexural properties and impact strength of the prepared WPCs were measured according to the relevant standard specifications. The flexural and impact strength of the manufactured composites significantly increased and reached a maximum when MAH dosage was 1.0 wt.%, whereas the flexural modulus after an initial decreased, also increased with MAH dosage. The increase in mechanical properties indicated that the presence of anhydride groups enhanced the interfacial adhesion between wood fiber and PP/PE blends.
Co-reporter:Chui-gen Guo;Qing-wen Wang
Journal of Forestry Research 2007 Volume 18( Issue 3) pp:203-207
Publication Date(Web):2007 September
DOI:10.1007/s11676-007-0041-9
MA-SEBS as compatibilizer and impact modifier was incorporated into Polypropylene/Wood Fiber (PP/WF) to enhance interface adhesion and impact strength of the composite. The effect of MA-SEBS content on the impact fracture behavior of PP/WF composites was studied. The impact properties of composites with 8% MA-SEBS reached the maximum value. And further increasing of MA-SEBS content to 10% did not improve the fracture toughness, but improved the stiffness of composites by DMA analysis. This was attributed to the improved PP/WF adhesion. As the MA-SEBS content is more than 8%, the molecule interaction of PP and WF was expected to much stronger than lower MA-SEBS. Scanning electron microscopy (SEM) was performed to analyze the impact fracture surface and showed a stronger affinity for the wood surfaces.
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