Effect of glycidyl methacrylate on the physical properties of wood–polymer composites

Chemical modification of pinewood was carried out by impregnating the wood with styrene as the impregnating monomer and in combination with a crosslinking monomer glycidyl methacrylate (GMA). Polymerization was carried out by catalyst heat treatment. Dimensional stability in terms of antiswell efficiency was determined and improved on treatment with polymer. Water uptake percentage was also improved for styrene‐GMA treated wood samples over styrene treated or untreated wood samples. Mechanical properties such as bending strength measured in terms of modulus of elasticity and modulus of rupture of polymer‐treated samples showed an improvement over untreated ones. Treatment also resulted an improvement in compressive strengths. Thermal properties of the wood samples were evaluated by thermogravimetric analyzer and differential scanning calorimeter. Biodegradability of the treated and untreated wood samples was determined and improvement was obtained on treatment. As a whole, styrene‐GMA treated wood samples showed more improvement over untreated or styrene‐treated samples. POLYM. COMPOS., 28:1–5, 2007. © 2007 Society of Plastics Engineers     

Chemical modification of rubber wood with styrene and glycidyl methacrylate

Rubber wood was impregnated with styrene and glycidyl methacrylate (GMA) as the crosslinking monomer. Polymerization was accomplished by catalyst heat treatment. Compressive strength both in parallel and perpendicular to fiber directions was measured and improvement was observed for wood polymer composites. Bending strength in terms of Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) was measured and found improved on treatment over the untreated wood samples. Hardness for treated wood was also improved. Dynamic Mechanical Analysis (DMA) indicated an increase in interaction between wood, styrene, and GMA. Biodegradation of the treated and untreated wood samples was also determined and found to be improved on treatment. Scanning electron microscopy (SEM) study showed the wood polymer interaction. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Effect of nanoclay and ZnO on the physical and chemical properties of wood polymer nanocomposite

Wood polymer composite (WPC) was prepared by using solution blended high density polyethylene, low density polyethylene, polypropylene, and poly(vinyl chloride) with Phragmites karka wood flour and polyethylene‐co‐glycidyl methacrylate (PE‐co‐GMA). The effect of addition of nanoclay and ZnO on the properties of the composite was examined. The distribution of silicate layers and ZnO nanopowder was studied by X‐ray diffractrometry and transmission electron microscopy. The improvement in miscibility among polymers due to addition of PE‐co‐GMA as compatibilizer was studied by scanning electron microscopy. WPC treated with 3 phr each of clay and ZnO showed an improvement in thermal stability and UV resistance. Mechanical and flame retarding properties were also enhanced after the incorporation of clay/ZnO nanopowder. Both water and water vapor absorption were found to decrease due to inclusion of nanoclay and ZnO in WPC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Wood–polymer composites prepared by the in situ polymerization of monomers within wood

Wood–polymer composites (WPCs) were prepared from poplar wood (P. ussuriensis Komarov) in a two‐step procedure. Maleic anhydride (MAN) was first dissolved in acetone and impregnated into wood; this was followed by a heat process; and then, glycidyl methacrylate (GMA) and styrene (St) were further impregnated into the MAN‐treated wood, followed by a second thermal treatment. Finally, the novel WPC was fabricated. The reactions occurring in the WPC, the aggregation of the resulting polymers, and their interaction with the wood substrate were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and dynamic mechanical analysis. The performance of WPC was also evaluated in terms of the mechanical properties and durability, which were then correlated with the structural analysis of the WPC. The test results show that MAN and GMA/St chemically reacted with the wood cell walls in sequence, and the quantity of hydroxyl groups in the wood cell walls was evidently reduced. Meanwhile, St copolymerized with GMA or MAN, and the resulting polymers mainly filled in the wood cell lumen in an amorphous form, tightly contacting the wood cell walls without noticeable gaps. As a result, the mechanical properties, decay resistance, and dimensional stability of the WPC were remarkably improved over those of the untreated wood, and its glass‐transition temperature also increased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of wood/styrene‐acrylonitrile copolymer/MMT nanocomposite

Wood polymer nanocomposite (WPNC) was prepared by impregnating Simul (Salmalia malabarica) wood with styrene‐acrylonitrile copolymer (SAN), glycidyl methacrylate(GMA), and a reactive polymerizable surfactant modified montmorillonite (MMT). The physical and mechanical properties of WPNC were investigated by using XRD, tensile tester, SEM, and FTIR. The polymer loading, dimensional stability, water uptake, mechanical property, and thermal stability were found to improve due to inclusion of MMT. SEM micrographs showed the presence of polymer and MMT into cell wall and cell lumen. FTIR analysis confirmed the presence of MMT and SAN in WPNC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Study on properties of simul wood (Bombax ceiba L.) impregnated with styrene acrylonitrile copolymer, TiO2, and nanoclay

Dimensional stability, thermal, and water repellency are very important properties of wood. In this research, wood polymer nanocomposite (WPNC) has been prepared by impregnation of styrene acrylonitrile copolymer (SAN), ??-trimethoxy silyl propyl methacrylate-modified TiO₂ nanoparticles, nanoclay into simul (Bombex ceiba L.) wood. The characterization of the composites was done by using Fourier transform infrared spectroscopy, X-ray diffractometry, and thermogravimetry. The resultant WPNC exhibited an improvement in water repellency, moisture resistance, dimensional stability, chemical resistance, hardness, and thermal stability. The maximum improvement in all the properties has been observed for the wood sample treated with SAN/TiO₂ (0.5?%)/nanoclay (0.5?%).     

Studies on properties of softwood (Ficus hispida)/PMMA nanocomposites reinforced with polymerizable surfactant-modified nanoclay

Soft wood (Ficus hispida) was chemically modified by impregnation of methyl methacrylate monomer, glycidyl methacrylate (GMA), a cross-linking agent, and montmorillonite (MMT) using catalyst heat treatment. MMT was modified by using a polymerizable surfactant 2-acryloloxy ethyl trimethyl ammonium chloride (ATAC) and a mixture of surfactants ATAC and cetyl trimethyl ammonium bromide (CTAB) in a molar ratio of (1:1). A comparative study on different properties of the prepared wood polymer nanocomposite (WPNC) based on impregnation of intercalating mixture containing MMA/GMA/clay modified by both the surfactants (ATAC and CTAB) and MMA/GMA/clay modified by only surfactant ATAC were done. FTIR, XRD, and TGA studies were employed for the characterization of clay and WPNC. WPNC prepared by using combined surfactant-modified clay along with MMA/GMA exhibited improved dimensional stability, chemical resistance, thermal stability, mechanical properties, and lower water uptake than that of WPNC prepared by using single surfactant-modified clay and MMA/GMA system.     

Use of nanoparticles for controlled release of biocides in solid wood

The fungicides tebuconazole and chlorothalonil were successfully incorporated into polymeric nanoparticles with median particle diameters of 100–250 nm. Polyvinylpyridine (PVPy) and polyvinylpyridine‐co‐styrene (10% styrene and 30% styrene) were employed as the polymer matrix. The size of the nanoparticle increased with increased styrene content. The biocide also affected particle size, with chlorothalonil consistently yielding larger nanoparticles than tebuconazole. The release of the biocides from the polymeric nanoparticles was studied by suspending them in water. The release rate of both tebuconazole and chlorothalonil decreased with increased styrene content in the matrix, and chlorothalonil consistently released more slowly from the polymeric nanoparticles than did tebuconazole. It was found that biocides were successfully introduced into solid wood by incorporating them within polymeric nanoparticles, suspending the nanoparticles in water, and using the suspension to treat the wood with conventional pressure treatments. Once in the wood, the polymer matrix serves as a reservoir for the biocide and controls its release rate into the wood. Southern pine sapwood samples were treated with biocide‐containing nanoparticles suspended in water, then exposed to the wood decay fungus Gloeophyllum trabeum using a simple wafer test. Samples exhibited fungal resistance at appropriate levels of biocide incorporation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 458–465, 2001     

Treatment of Caribbean pine by in situ polymerization of styrene and furfuryl alcohol

Caribbean pine impregnated by the full cell treatment schedule with styrene, furfuryl alcohol (FFA), and styrene–FFA monomers was cured for 48 h at 100°C. Styrene did not penetrate inside the wood cell wall; instead, it adhered on the cell wall surfaces and fill cell lumens. The volume contraction during the formation of polystyrene causes the volume contraction of the wood sample. The permanent volumetric swelling is attained only for samples treated with FFA, which is caused by cell wall impregnation. The dimensional stability of the treated wood samples is evaluated with the antiswell efficiency coefficient (ASE). The water repellency is expressed as the water‐repellent effectiveness (WRE). Treatment with styrene improves the water repellence, whereas a double treatment increases the dimensional stability. Lixiviation slightly affects the ASE and WRE coefficients. The treatments improve the Shore D hardness in comparison to untreated wood. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1763–1769, 2004     

Modification of rubber wood with styrene in combination with diethyl allyl phosphate as the flame‐retardant agent

Rubber wood (Hevea brasiliensis) polymer composite was prepared using styrene as the monomer in combination with diethyl allyl phosphate (DEAP) to improve flame‐retardant property. DEAP was synthesized, characterized and incorporated into wood with styrene. The polymerization was accomplished by catalyst heat treatment using AIBN as the catalyst. The properties of wood–polymer composites (WPC) like water absorption, swelling in water, hardness, modulus of elasticity (MOE), modulus of rupture (MOR) etc. were improved on treatment. The thermal degradation behavior of WPC was evaluated using thermogravimetric analysis (TGA) and the flammability of the WPC was evaluated using the limiting oxygen index (LOI) test. It was observed that fire retardancy of WPC improved on incorporation of DEAP. FTIR spectroscopy and SEM study showed the interaction between wood and the polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Physical and mechanical properties of nanocomposite barrier film containing encapsulated nanoclay

Waterborne poly(styrene‐co‐butyl acrylate) was prepared via miniemulsion polymerization in which nanoclay (Cloisite® 30B, modified natural MMT) in different concentrations was encapsulated. Scanning electron microscopy, X‐ray diffraction, and transmission electron microscopy confirmed the encapsulation and intercalated‐exfoliated structure of Cloisite® 30B within poly(styrene‐co‐butyl acrylate). The effect of nanoclay content on water vapor permeability, water uptake, oxygen permeability, thermal, and mechanical properties of thin films containing 1.5, 2.56, 3.5, and 5.3 wt % encapsulated Cloisite® 30B in poly(styrene‐co‐butyl acrylate) was investigated. The presence of encapsulated Cloisite® 30B within the polymer matrix improved tensile strength, Young's modulus, and toughness of the nanocomposites depending on the nanoclay content. Water vapor transmission rate, oxygen barrier properties, and thermal stability were also improved. The results indicated that the incorporation of Cloisite® 30B in the form of encapsulated platelets improved physicomechanical properties of the nanoclay‐polymer composite barrier films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Rubberwood–polymer composites based on glycidyl methacrylate and diallyl phthalate

Wood–polymer composites (WPC) of rubberwood (Hevea Brasiliensis) were prepared by impregnating the wood with glycidyl methacrylate (GMA), combinations of glycidyl methacrylate and diallyl phthalate (GMA–DAP), or diallyl phthalate (DAP) alone. Polymerization was carried out by catalyst-heat treatment. The results showed that WPC based on GMA exhibited greater dimensional stability (results of antishrink efficiency after six days of soaking) about five times than those based on DAP alone. Flexural [Modulus of Elasticity (MOE), Modulus of Rupture (MOR), and toughnes], compressive, and impact properties for all the samples tested are improved, especially for those with higher chemical loading. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1221–1226, 1998     

Effect of GMA on monodisperse epoxy‐functionalized polymer microsphere particles by dispersion copolymerization of styrene with glycidyl methacrylate

Monodisperse poly[styrene‐co‐glycidyl methacrylate (GMA)] microparticles were synthesized by dispersion copolymerization in a water–ethanol medium. The effects of various polymerization parameters on the particle size and size distribution of the dispersion copolymerization were investigated. The dispersion of polymer particles decreased when the GMA was added if the polystyrene homopolymer particles were polydispersed. The GMA acted as a comonomer as well as a costabilizer in the dispersion copolymerization of styrene with GMA. The solvency of the monomer increased with the concentration of GMA in the polymerization medium because GMA has a greater hydrophilicity than styrene, resulting in a large particle size and a slow polymerization rate. From an HCl–dioxane analysis of the poly(styrene‐co‐GMA) microparticles, great amounts of epoxy groups were detected after the completion of dispersion copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1206–1212, 2001     

Synergistic effect of nanoTiO2 and nanoclay on mechanical, flame retardancy, UV stability, and antibacterial properties of wood polymer composites

Wood–polymer nanocomposite (WPNC) based on styrene–acrylonitrile copolymer (SAN), γ-trimethoxy silyl propyl methacrylate-modified TiO₂ nanoparticles, and nanoclay was prepared by impregnation. The flexural, tensile, and flame-retardant properties were improved. UV stability was evaluated by photo-induced weight loss, FTIR, loss in mechanical properties, and scanning electron microscopy. The results showed that UV stability was maximum for wood sample treated with SAN/TiO₂ (0.5 %)/nanoclay (0.5 %). The presence of TiO₂ nanoparticles in WPNC-exhibited antibacterial activity.     

Polylactide toughening with epoxy‐functionalized grafted acrylonitrile–butadiene–styrene particles

Glycidyl methacrylate functionalized acrylonitrile–butadiene–styrene (ABS‐g‐GMA) particles were prepared and used to toughen polylactide (PLA). The characteristic absorption at 1728 cm^?1 of the Fourier transform infrared spectra indicated that glycidyl methacrylate (GMA) was grafted onto the polybutadiene phase of acrylonitrile–butadiene–styrene (ABS). Chemical reactions analysis indicated that compatibilization and crosslinking reactions took place simultaneously between the epoxy groups of ABS‐g‐GMA and the end carboxyl or hydroxyl groups of PLA and that the increase of GMA content improved the reaction degree. Scanning electron microscopy results showed that 1 wt % GMA was sufficient to satisfy the compatibilization and that ABS‐g‐GMA particles with 1 wt % GMA dispersed in PLA uniformly. A further increase of GMA content induced the agglomeration of ABS‐g‐GMA particles because of crosslinking reactions. Dynamic mechanical analysis testing showed that the miscibility between PLA and ABS improved with the introduction of GMA onto ABS particles because of compatibilization reactions. The storage modulus decreased for the PLA blends with increasing GMA content. The decrease in the storage modulus was due to the chemical reactions in the PLA/ABS‐g‐GMA blends, which improved the viscosity and decreased the crystallization of PLA. A notched impact strength of 540 J/m was achieved for the PLA/ABS‐g‐GMA blend with 1 wt % GMA, which was 27 times than the impact strength of pure PLA, and a further increase in the GMA content in the ABS‐g‐GMA particles was not beneficial to the toughness improvement. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of silica nanopowder on the properties of wood flour/polymer composite

Low‐density polyethylene (LDPE), high‐density polyethylene (HDPE), polypropylene (PP), and polyvinyl chloride (PVC) (1:1:1:0.5) were solution blended by using a mixture of solvents consisting of xylene and tetrahydrofuran (THF) (70:30). SiO₂ nanoparticles were modified by cetyl trimethyl ammonium bromide (CTAB). Wood polymer composites (WPC) were prepared by using polymer mixture, polyethylene‐co‐glycidyl methacrylate (PE‐co‐GMA), wood flour, and modified SiO₂. X‐ray diffraction (XRD) studies showed that the intensity of the peaks of polymer mixture decreased due to incorporation of SiO₂. The dispersion of SiO₂ nanoparticles and morphological characteristics were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The interaction between SiO₂ nanoparticles, PE‐co‐GMA, polymer mixture, and wood was studied by Fourier transform infrared spectroscopy (FTIR). Tensile and flexural properties of the composites improved significantly due to the incorporation of SiO₂ nanoparticles. Thermal stability, hardness, flame retardancy, and water resistance capacity were also found to enhance. Maximum improvement in properties was observed by the inclusion of 3 phr modified SiO₂ in WPC. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Properties of Colloidal Silica‐Fixed and Propionylated Wood Composites (I): Preparation and Dimensional Stability of the Composites

Abstract

Colloidal silica‐fixed and propionylated dual‐treated wood (CSPW) composites were prepared and their dimensional stability evaluated. The results indicated that: (1) colloidal silica only–treated wood composites had minimal dimensional stability improvement, and they could be propionylated similarly to untreated wood specimens and (2) CSPW composites had a high antiswelling efficiency (ASE) during liquid water or moisture vapor absorption relative to propionylated only–treated wood, and a lower moisture excluding efficiency (MEE) during the moisture vapor absorption than propionylated wood.     

Effect of polymer in situ synthesized from methyl methacrylate and styrene on the morphology,thermal behavior,and durability of wood

A novel fast‐growing poplar wood, Populus ussuriensis Kom, was prepared into wood‐polymer composite by the in situ polymerization of methyl methacrylate and styrene through a vacuum/pressure and subsequent catalyst‐thermal process. scanning electron microscopy observation, FTIR, X‐ray diffraction, dynamic mechanical analysis, and thermogravimetric/derivative thermogravimetric analysis indicated that the resulted polymer well filled up wood cell lumen in an amorphous form and reinforced wood matrix, which resulted in the improvement of glass transition temperature, storage modulus, and thermal stability of wood. The decay resistance and dimensional stability of wood were also improved. Such wood‐based composite could be potentially used as reinforced material in construction fields. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and application of MDPE‐g‐GMA as reactive compatibilizer in blends of MDPE/PET and MDPE/PA6

In the present study, glycidyl methacrylate (GMA) grafted medium density polyethylene (MDPE‐g‐GMA) was synthesized in the molten state and applied as a reactive compatibilizer in MDPE/polyamid6 (PA6) and in MDPE/poly(ethylene terephtalate) (PET) blends. Graft copolymerization of GMA onto MDPE was performed in presence and absence of styrene, with different concentrations of dicumyl peroxide (DCP) as a radical initiator. In the presence of styrene, the MDPE‐g‐GMA with 6% GMA was obtained by addition of only 0.1 phr of DCP. Furthermore, the maximum grafting was reached when 0.6 and 0.7 phr concentration of DCP for styrene containing and styrene free samples were used, respectively. Torque‐time measurement showed faster grafting reaction rate in the presence of styrene. Four MDPE‐g‐GMA samples were selected as compatibilizers in the blends. Furthermore, the effects of melt flow index and grafting content of compatibilizers on mechanical properties and morphology of the blends were investigated through tensile tests and SEM analysis. Tensile test results indicated that the presence of compatibilizers in the blends led to 250 and 133% increase in elongation at break for PA6 and PET blends, respectively. Moreover, the best tensile results for blends were obtained using MDPE‐g‐GMA with high flow ability. The average particle size of the dispersed phase decreased by 350% for PA6 and 300% for PET blends compared with nonreactive blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Evaluation of dimensional stability,weathering and decay resistance of modified pine wood by in-situ polymerization of styrene

Abstract

In this study, polystyrene modified Scots pine (Pinus sylvestris L.) wood was investigated upon artificial weathering, decay resistance, dimensional stability and water uptake properties. Polystyrene modification was carried out on pretreated wood by immersion of wood into styrene monomer and further polymerization. The resistance of modified wood against cycles of UV and water exposures was examined by artificial weathering test for 672?hours, and decay resistance was evaluated by attacks of Coniophora puteana and Trametes versicolor on the samples. During the artificial weathering, color and surface roughness of the samples, and macroscopic changes were determined periodically. Changes in the surface chemistry and morphology of the weathered samples were investigated by ATR-FTIR and SEM, respectively. It was proven that polystyrene effectively protected pine samples from both fungi even after leaching procedure, but it was more effective in preventing C. puteana attacks than T. versicolor attacks. As a result of artificial weathering, the surface of all samples was darkened. However, changes in color and roughness as well as crack formations of the modified sample surfaces were found less than those of the untreated samples. Polystyrene also provided considerable improvement on dimensional stability, as well as water repellence of wood.