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     

Effect of SiO2 and nanoclay on the properties of wood polymer nanocomposite

Wood polymer composite (WPC) were developed by using solution blended high density polyethylene, low density polyethylene, polypropylene, poly(vinyl chloride), Phragmites karka wood flour and polyethylene-co-glycidyl methacrylate. The effect of addition of nanoclay and SiO₂ on the properties of the composite was examined. X-ray diffractrometry and transmission electron microscopy were used to study the distribution of silicate layers and SiO₂ nanopowder in the composite. The improvement in miscibility among the polymers and WPC was studied by scanning electron microscopy. Fourier transform infrared spectroscopy study revealed the interaction between polymer, wood, clay and SiO₂. WPC treated with 3 wt% each of clay and SiO₂ showed an excellent improvement in mechanical properties, thermal and flame retarding properties. Water uptake of WPC was found to decrease on incorporation of nanoclay and SiO₂ in WPC.     

Influence of silica nanoparticles functionalized with poly(butyl acrylate‐co‐glycidyl methacrylate)‐g‐diaminodiphenyl sulfone on the mechanical and thermal properties of bismaleimide nanocomposites

The silica nanoparticles functionalized with poly(butyl acrylate‐co‐glycidyl methacrylate)‐g‐diaminodiphenyl sulfone (P(BA‐co‐GMA)‐g‐DDS)) were prepared via atom transfer radical polymerization and ring open reaction, and characterized by Fourier transform infrared and X‐ray photoelectron spectroscopy. Subsequently, the influence of SiO₂ content on the mechanical and thermal properties for the bismaleimide (BMI) resin nanocomposites modified with pristine SiO₂ and SiO₂‐P(BA‐co‐GMA)‐g‐DDS) was investigated. It was found that SiO₂‐P(BA‐co‐GMA)‐g‐DDS) was more effective as a modifier than pristine SiO₂. The most significant improvement of the impact strength (+108.7%) and flexural strength (+64.5%) was obtained with SiO₂‐P(BA‐co‐GMA)‐g‐DDS) at 0.5 wt% content. Moreover, the thermal properties of nanocomposites were distinctly improved with the addition of functionalized SiO₂. The reasons for these changes were discussed in this article. POLYM. COMPOS., 34:2154–2159, 2013. © 2013 Society of Plastics Engineers     

Structure and Performance of Poly(vinylidene chloride‐co‐vinyl chloride) Porous Membranes with Different Additives

Poly(vinylidene chloride‐co‐vinyl chloride) (P(VDC‐co‐VC) membranes were prepared by non‐solvent‐induced phase separation and adjusted by adding water‐soluble polyethylene glycol (PEG) and water‐insoluble silicon dioxide (SiO₂) hydrophilic nanoparticles. The structure of pores and antifouling performance were investigated to illustrate the effect of these nanoparticles. The cross section of the P(VDC‐co‐VC) membrane exhibited more macropores and the typical finger‐like pores turned into more vertically interconnected ones with increasing PEG content, while the number and size of finger‐like pores became less with increasing SiO₂ content. Considering the filtration and antifouling experiments, the presence of hydrophilic PEG and SiO2 nanoparticles in the P(VDC‐co‐VC) polymer matrix improved the membrane performance in terms of high flux, high BSA rejection ratio, and fouling resistance.     

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     

Blending ultrahigh‐molecular‐weight polyethylene and poly(ethylene/10‐undecen‐1‐ol) in one nascent particle

Ultrahigh‐molecular‐weight polyethylene (UHMWPE)/polar polyethylene (PE) composites were blended in one nascent particle by in situ polymerization with a hybrid catalyst. Polystyrene‐coated SiO₂ particles were used to support the hybrid catalyst. Fe(acac)₃/2,6‐bis[1‐(2‐isopropylanilinoethyl)] was supported on SiO₂ for the synthesis of UHMWPE, whereas [PhN?C(CH₃)CH?C(Ph)O]VCl₂ was immobilized on a polystyrene layer to prepare a copolymer of ethylene and 10‐undecen‐1‐ol (polar PE). Importantly, the core part of the supports (the polystyrene layer) exhibited pronounced transfer resistance to 10‐undecen‐1‐ol; this provided an opportunity to keep the inside iron active sites away from the poisoning of 10‐undecen‐1‐ol. Therefore, UHMWPE was simultaneously synthesized with polar PE by in situ polymerization. Interestingly, the morphological results show that UHMWPE and the polar PE were successfully blended in one nascent polymer. This improved the miscibility of the composites, where most of the chains were difficult to crystallize because of the strong interactions between the PE chains and polar chains. The blends showed an extremely low crystallinity, that is, 9.9%. Finally, the hydrophilic properties of the polymer composites were examined. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46652.     

Properties of softwood polymer composites impregnated with nanoparticles and melamine formaldehyde furfuryl alcohol copolymer

Wood polymer composites (WPC) based on nano SiO₂ and nanoclay were prepared by the impregnation of melamine formaldehyde‐furfuryl alcohol copolymer, 1,3‐dimethylol 4,5‐dihydroxy ethylene urea, a crosslinking agent, and a renewable polymer. Surface modification of SiO₂ and formation of composites were characterized by Fourier Transform Infrared Spectroscopy (FTIR). X‐ray diffractometry (XRD) studies indicated a decrease in crystallinity of the composites. The crystallinity index value of wood cellulose decreased from 63.8 to 30.8 as determined from FTIR and XRD studies. Scanning Electron Microscopy was used for morphological characterization. Transmission Electron Microscopy (TEM) showed uniform distribution of nano SiO₂ and nanoclay in the composites. Remarkable reduction in water uptake capacity was observed for the treated wood samples. It was found to reduce from 142.2% to 30.2%. Both tensile and flexural properties increased upto 76.5% and 23.6%, respectively in the WPCs. An improvement in chemical resistance, flame retardancy and thermal stability were observed in the composites as a result of treatment. POLYM. ENG. SCI., 54:1019–1029, 2014. © 2013 Society of Plastics Engineers     

Effect of silicon dioxide on crystallization and melting behavior of polypropylene

The crystallization and melting behavior of isotactic polypropylene (iPP) and polypropylene copolymer (co‐PP) containing silicon dioxide (SiO₂) were investigated by differential scanning calorimeter (DSC). SiO₂ had a heterogenous nucleating effect on iPP, leading to a moderate increase in the crystallization temperature and a decrease in the half crystallization time. However, SiO₂ decreased the crystallization temperature and prolonged the half crystallization time of co‐PP. A modified Avrami theory was successfully used to well describe the early stages of nonisothermal crystallization of iPP, co‐PP, and their composites. SiO₂ exhibited high nucleation activity for iPP, but showed little nucleation activity for co‐PP and even restrained nucleation. The iPP/SiO₂ composite had higher activation energy of crystal growth than iPP, indicating the difficulty of crystal growth of the composite. The co‐PP/SiO₂ composite had lower activation energy than co‐PP, indicating the ease of crystal growth of the composite. Crystallization rates of iPP, co‐PP, and their composites depended on the nucleation. Because of its high rate of nucleation, the iPP/SiO₂ composite had higher crystallization rate than iPP. Because of its low rate of nucleation, the co‐PP/SiO₂ composite had lower crystallization rate than co‐PP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1889–1898, 2006     

Thermal properties of tropical wood–polymer composites

Wood–polymer composites (WPC) of Geronggang (GE; Cratoxylon arborescens), a light tropical hardwood, impregnated with methyl methacrylate (MMA), styrene-co-acrylonitrile (3: 2; STAN), methyl methacrylate-co-bis (2-chloroethyl) vinyl phosphonate (3 : 1; MVP) and methyl methacrylate-co-bis (chloropropyl)-2-propene phosphonate (3:1;MPP), were prepared by in situ polymerization using γ-radiation or catalyst-heat treatment. Thermal characterization of these WPC by limiting oxygen index measurements (LOI), thermogravimetry (TG), and differential scanning calorimetry (DSC) showed that the impregnants greatly modified the wood properties. The LOI values of the GE–MVP and GE–MPP composites were much higher than that for GE and the other composites, indicating the effectiveness of the phosphonates as flame retardants. Concomitantly, the flaming characteristics also compared favorably against that for GE and the other composites. The decomposition temperature and maximum rate of weight loss determined by TG for GE–MVP and GE–MPP were substantially reduced, whereas the char yields were greatly higher. These observations again indicate that phosphonates imparted flame-retarding properties to their composites. The thermal properties of GE–MMA and GE–STAN composites were not vastly different from that of untreated GE. Flame retardancy in the phosphonate-containing composites was effected through both the condensed- and gaseous-phase mechanisms due to the presence of phosphorus and chlorine, respectively. Indication of grafting of polymer to wood was found for GE–STAN, GE–MVP, and GE–MPP composites, but not for GE–MMA. Composites prepared by γ-radiation or by the catalyst-heat treatment had similar thermal characteristics.     

Tribological properties of bismaleimide composites with surface‐modified SiO2 nanoparticles

In this article, the surface of SiO₂ nanoparticles was modified by silane coupling agent N‐(2‐aminoethyl)‐γ‐aminopropylmethyl dimethoxy silane. The bismaleimide nanocomposites with surface‐modified SiO₂ nanoparticles or unmodified SiO₂ nanoparticles were prepared by the same casting method. The tribological performance of the nanocomposites was studied on an M‐200 friction and wear tester. The results indicated that the addition of SiO₂ nanoparticles could decrease the frictional coefficient and the wear rate of the composites. The nanocomposites with surface‐modified SiO₂ nanoparticles showed better wear resistance and lower frictional coefficient than that with the unmodified nanoparticles SiO₂. The specific wear rate and the steady frictional coefficient of the composite with 1.0 wt % surface‐modified SiO₂ nanoparticles are only 1.8 × 10^?6 mm³/N m and 0.21, respectively. The dispersion of surface‐modified SiO₂ nanoparticles in resin matrix was observed with transmission electron microscope, and the worn surfaces of pure resin matrix and the nanocomposites were observed with scanning electron microscope. The different tribological behavior of the resin matrix and the filled composites should be dependent on their different mechanical properties and wear mechanism. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Mechanical properties of low nano‐silica filled high density polyethylene composites

Modification of nanoparticles through graft polymerization is able to change the chemical nature of the particles' surfaces and provides an effective means for the preparation of nano‐fillers specified for composites manufacturing. The present work focuses on the mechanical role of grafted nano‐SiO₂ particles in high density polyethylene composites prepared by melt compounding. The experimental results show that at a content of 0.75 vol%, the modified nano‐silica results in a rise in tensile stiffness, tensile strength and impact strength of the composites. The grafted nanoparticles can improve the mechanical performance of the matrix polymer more effectively than the untreated version. In addition, a further enhancement of the composites stiffness and strength can be achieved by crosslinking the concentrated masterbatches, which has not yet been revealed in the authors' previous works on grafted nano‐SiO₂ particles/polypropylene composites. It is thus revealed that the introduction of the grafting polymers onto the nanoparticles increases the tailorability of the composites.     

A novel approach to prepare PBT nanocomposites with elastomer‐modified SiO2 particles

Poly(butylenes terephthalate) (PBT)/SiO₂ nanocomposites with uniform dispersion, strong interfacial adhesion, and improved mechanical properties have been prepared by a novel approach. Ethylene‐methyl acrylate‐glycidyl methacrylate (E‐MA‐GMA) elastomer chains were first chemically grafted onto the surface of SiO₂ nanoparticles. Fourier transform infrared spectra result shows that elastomer‐modified SiO₂ nanoparticles exhibit absorption at 2963–2862 cm⁻¹ of the stretching modes of C H, which suggests the reaction between the hydroxyl groups of SiO₂ surface and epoxy groups of E‐MA‐GMA. And the binding energy of Si2p and O1s of the elastomer‐modified SiO₂ shifts to lower binding energy, which further confirms the formation of Si O C bonds. This surface treatment allows SiO₂ nanoparticles homogeneously dispersing in PBT matrix. The morphology with loose aggregates contains networked SiO₂ particles with an interparticle distance ranging from 0 to 30 nm. As a result, the storage modulus and the tensile properties of PBT/E‐MA‐GMA‐SiO₂ nanocomposites are higher than those of pure PBT and PBT with untreated SiO₂. The incorporation of E‐MA‐GMA‐modified SiO₂ particles increases the tensile strength and modulus to 58.4MPa and 2661MPa respectively, which is 8% and 16% higher than those of pure PBT. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers     

Reinforced thermal conductivity and mechanical properties of in situ microfibrillar composites through multistage stretching extrusion

To surmount difficulty of the melt processing and deterioration of mechanical properties of polymer composites induced by high fraction of the reinforced fibers and thermal conductive fillers, polyethylene (PE)/boron nitride (BN)/polyamide 6 (PA6) and PE/BN/poly(‐hydroxybenzate‐co‐DOPO‐benzenediol dihydrodiphenyl ether terephthalate) (PHDDT) in situ microfibrillar composites were prepared through multistage stretching extrusion. The experimental results showed that both the tensile and impact strength of the PE/BN/PA6 and PE/BN/PHDDT composites were improved. Meanwhile, the thermal conductivities of the PE/BN, PE/BN/PA6, and PE/BN/PHDDT composites were also reinforced. Based on the equation proposed by Y. Agari, the new modified equations can well predict the thermal conductivity of the composites prepared through multistage stretching extrusion with different number of laminating‐multiplying elements. In addition, it was found that PHDDT can act as a “processing aid” to reduce the viscosity of the PE/BN composites. POLYM. COMPOS., 38:2663–2669, 2017. © 2015 Society of Plastics Engineers     

Stabilized electrospinning of heat stimuli/in situ crosslinkable nanofibers and their self‐same nanocomposites

We present a strategy for stabilizing the morphological integrity of electrospun polymeric nanofibers by heat stimuli in situ crosslinking. Amorphous polymer nanofibers, such as polystyrene (PS) and its co‐polymers tend to lose their fiber morphology during processing at temperatures above their glass transition temperature (T_g) typically bound to happen in nanocomposite/structural composite applications. As an answer to this problem, incorporation of the crosslinking agents, phthalic anhydride (PA) and tributylamine (TBA), into the electrospinning polymer solution functionalized by glycidylmethacrylate (GMA) copolymerization, namely P(St‐co‐GMA), is demonstrated. Despite the presence of the crosslinker molecules, the electrospinning polymer solution is stable and its viscosity remains unaffected below 60 °C. Crosslinking reaction stands‐by and can be thermally stimulated during post‐processing of the electrospun P(St‐co‐GMA)/PA‐TBA fiber mat at intermediate temperatures (below the T_g). This strategy enables the preservation of the nanofiber morphology during subsequent high temperature processing. The crosslinking event leads to an increase in T_g of the base polymer by 30 °C depending on degree of crosslinking. Crosslinked nanofibers are able to maintain their nanofibrous morphology above the T_g and upon exposure to organic solvents. In situ crosslinking in epoxy matrix is also reported as an example of high temperature demanding application/processing. Finally, a self‐same fibrous nanocomposite is demonstrated by dual electrospinning of P(St‐co‐GMA) and stabilized P(St‐co‐GMA)/PA‐TBA, forming an intermingled nanofibrous mat, followed by a heating cycle. The product is a composite of crosslinked P(St‐co‐GMA)/PA‐TBA fibers fused by P(St‐co‐GMA) matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44090.     

Antibacterial activity and antistatic composites of polyester/Ag‐SiO2 prepared by a sol–gel method

Poly(butylene adipate‐co‐terephthalate) (PBAT) composites containing silver‐silica (Ag‐SiO₂) were prepared using an in‐situ sol–gel process. Maleic anhydride‐grafted PBAT (PBAT‐g‐MA) and multihydroxyl‐functionalized Ag‐SiO₂ were used to improve the compatibility and dispersibility of Ag‐SiO₂ within the PBAT matrix. The composites were characterized morphologically using transmission electron microscopy and chemically using Fourier transform infrared spectrometry. The existence of Ag‐SiO₂ nanoparticles on the substrate was confirmed by the ultraviolet–visible absorption spectra. The antibacterial and antistatic properties of the composites were evaluated whether SiO₂ enhanced the electrical conductivity was tested as well as whether Ag enhanced the antibacterial activity of the PBAT‐g‐MA/SiO₂ or PBAT/SiO₂ composites. The PBAT‐g‐MA/SiO₂ or PBAT/SiO₂ composite that contained Ag had better antibacterial activity (more than 1.3‐fold). The functionalized PBAT‐g‐MA/Ag‐SiO₂ composite can markedly enhanced antibacterial and antistatic properties due to the carboxyl groups of maleic anhydride, which acted as coordination sites for the Ag‐SiO₂ phase, allowing the formation of stronger chemical bonds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Investigations on the surface structure and properties of silica‐polyamine composites on the nanoscales and microscales

The structure and properties of silica polyamine composites (SPC) made from microparticles of amorphous silica gel (300–600 microns) and silica nanoparticles (10–20 nm) modified with aminopropyltrimethoxysilane (APTMS), poly(allylamine) (PAA) or poly(ethyleneimine) (PEI) have been studied. The APTMS nano‐hybrids showed batch capacities for copper equal to or better than the corresponding polymer‐based micro‐hybrids. Loading of the PEI on the nanoparticles was independent of molecular weight of the polymer. Dynamic light scattering measurements showed that the SiO₂ nanoparticles and the composites made from them aggregate in water and the degree of aggregation is dependent on the surface modification. All of the amine‐modified materials were catalysts for the Knoevenagel reaction but interestingly, the microparticles modified with APTMS were better catalysts than the corresponding nanoparticles or the polyamine modified composites. Solid‐state ¹⁹Si NMR has been used to elucidate the surface structure of the various composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42271.     

Studies on electro‐optical properties of polymer matrix/LC/SiO2 nanoparticles composites

Polymer‐dispersed liquid crystal (PDLC) films were prepared by ultraviolet light‐induced polymerization of photopolymerizable monomers in nematic liquid crystal (LC)/monomers/SiO₂ nanoparticles composites, and the effect of SiO₂ nanoparticles on the electro‐optical properties of PDLC films was studied. The observed effect showed that by the adjustment of the SiO₂ nanoparticles content, the refractive index ratio of the LC and polymer could be modulated, and the electro‐optical properties of the polymer matrix/LC/SiO₂ nanoparticles composites could be optimized. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Porous properties of poly(glycidyl methacrylate‐co‐trimethylolpropane trimethacrylate) resins synthesized by suspension polymerization

Porous copolymer beads of 2,3‐epoxypropyl methacrylate (glycidyl methacrylate, GMA) crosslinked with 2‐ethyl‐2‐(hydroxymethyl)‐propan‐1,3‐diol trimethacrylate (trimethylolpropane trimethacrylate, TRIM) were prepared with toluene and octan‐2‐one as porogens by suspension polymerization. With an increase in the ratio of porogen to monomer, the total pore volume of poly(GMA‐co‐TRIM) increases significantly, whereas the surface area hardly changes. The total pore volume also depends on the nature of the porogen, exhibiting a maximum at the larger GMA contents in the monomer mixture of 50% v/v with octan‐2‐one and of 60% v/v with toluene, compared to that at the GMA content of 25% v/v with a 9/1 v/v mixture of cyclohexanol and dodecan‐1‐ol [Verweij, P. D.; Sherrington, D. C. J Mater Chem 1991, 1 (3), 371]. The surface area decreases significantly with an increase in the ratio of GMA to TRIM, almost regardless of the nature of the porogen. The porous properties of poly(GMA‐co‐TRIM) was well explained on the basis of phase separation, particularly taking into account not only the solubility parameters of the resulting polymer network and porogen but also the rigidity of TRIM. The porous poly(GMA‐co‐TRIM) may be a promising polymer matrix of novel materials for separation of boron isotopes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2374–2381, 2002     

Poly(glycidyl methacrylate‐co‐3‐thienyl‐methylmethacrylate) based working electrodes for hydrogen peroxide biosensing

BACKGROUND: Hydrogen peroxide biosensors based on Poly(glycidyl methacrylate‐co‐3‐thienylmethylmethacrylate)/ Polypyrrole [Poly(GMA‐co‐MTM)/PPy] composite film were reported. Poly(GMA‐co‐MTM) including various amounts of GMA and MTM monomers was synthesized via the radical polymerization. Enzyme horseradish peroxidase (HRP) was trapped in Poly(GMA‐co‐MTM)/PPy composites during the electropolymerization reaction between pyrrole and thiophene groups of MTM monomer, and chemically bonded via the epoxy groups of GMA. Analytical parameters of the fabricated electrodes were calculated and are discussed in terms of film electroactivity and mass transfer conditions of the composite films. RESULTS: The amount of electroactive HRP was found to be 1.25, 0.34 and 0.213 µg for the working electrodes of Poly(GMA_30%‐ co‐MTM_70%)/PPy/HRP, Poly(GMA_85%‐co‐MTM_15%)/PPy/HRP and Poly(GMA_90%‐co‐MTM_10%)/PPy/HRP, respectively. Optimal response of the fabricated electrodes was obtained at pH 7 and an operational potential of ? 0.35 V. It was observed that effective enzyme immobilization and electroactivity of the composite films could be changed by changing the ratios of GMA and MTM fractions of Poly(GMA‐co‐MTM) based working electrodes. CONCLUSION: The amount of electroactive enzyme increases with increasing MTM content of the final copolymer. High operational stabilities of the biosensors can be attributed to the strong covalent enzyme linkage via the epoxy groups of GMA due to preventing enzyme deterioration and loss. A more convenient microenvironment for mass transfer was provided for the electrodes by higher GMA ratios. It is observed that mass transfer is dominated by the mechanism of electron transfer to obtain effective sensitivity values. This work contributes to discussions clarifying the problems regarding the design parameters of biosensors. Copyright © 2011 Society of Chemical Industry     

FTIR characterization of tropical wood–polymer composites

Wood–polymer composites (WPC) of Geronggang (Cratoxylon arborescens), a light tropical hardwood, impregnated with methyl methacrylate (MMA), methyl methacrylate-co-acrylonitrile (1 : 1; MAN), and styrene-co-acrylonitrile (3 : 2; STAN), were prepared by in situ polymerization using gamma radiation or the catalyst–heat treatment. The FTIR spectra of the three types of WPC, with polymer loadings ranging from 10 to 70%, were compared with that of the wood itself and the respective polymers. Characteristic peaks due to C?O vibration of MMA, C?N stretching of acrylonitrile, and ring stretching and bending of styrene monomers, were prominent in the samples that had higher polymer loadings. For the copolymeric systems, quantitation of the FTIR spectra of these characteristic peaks enabled calculations of incorporated acrylonitrile and styrene monomers in the composites to be made. The FTIR spectra of the residues remaining, after exhaustive extraction to remove homopolymer, showed that graft copolymerization of wood components with acrylonitrile and styrene monomers was possible, but not with MMA. Composites prepared by the two methods, gamma radiation and the catalyst–heat treatment, were shown to be chemically very similar.