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In this work, a novel melamine-formaldehyde-Fe3O4 foam was prepared from a mixture containing melamine-ethanolamine-formaldehyde resin, melamine-glycol-formaldehyde resin and carboxylated Fe3O4 nanoparticles by microwave foaming method. The two resins were characterized by 13C-NMR, respectively. The structures of foams, mechanical and fire-retardant properties were experimentally characterized separately by scanning electron microscopy, universal testing machine, limit oxygen index, thermogravimetry-differential thermal analysis, and Fourier transform infrared spectra. The effects of the resin viscosity, emulsifier, nucleating agent, curing agent, silicone oil, microwave heating time and blowing agent on the structure of foam were investigated. Results showed that the properties of foam were decided by not only the molecular structure but also structure of foam, and the carboxylated Fe3O4 nanoparticles can improve the toughness and flame retardant properties of magnetic foam obviously from both aspects. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2688–2697, 2013

Chicken feather fibers (CFFs) have potential application in light weight composites. We investigated the physical properties of epoxy polymer composites reinforced with CFFs and glass fibers. CFFs or hybrid fiber (glass fiber and CFFs) composites reduced the density upto 30–40% when compared with glass fiber reinforced composites. The CFF composites has a storage modulus of about 3.5 GPa and a flexural strength of about 50–80 MPa. The hybrid fiber composite has better mechanical properties than CFF composites while having increased bio-based content. This study demonstrated a new way to utilize CFFs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44013.

This study is primarily focused on the possibility to use a sulfur vulcanized low-molecular weight polybutadiene with isocyanate end groups in the main chain as a matrix for composite materials reinforced with common inorganic particulate fillers (calcium carbonate, titanium dioxide, titanium dioxide modified with zinc, respectively). The isocyanate groups were used for a preliminary crosslinking of the oligomeric polybutadiene with glycerol as a three-functional crosslinker. The prepared polybutadiene-based polyurethane gel was subsequently vulcanized with sulfur. It has been shown that the vulcanized liquid polybutadiene could be successfully applied as the matrix for composite materials with inorganic filler. The resulting composite materials exhibited enhanced mechanical properties (tensile strength, flexural strength, hardness) and retain a high chemical resistance against hydrolysis and aqueous solutions of chemicals. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Conjugated aromatic oligo(azomethine) derivatives (oligo-AMs) were prepared by the condensation of terephtaldehyde 4,4′-diformylbiphenyl bis(4-formylphenyl) ether and p-phenylene diacrolein with 1,4-diaminobenzene at room temperature. The structures of the synthesized oligomers were characterized by FTIR, 1H-NMR, TGA–DTG, UV–vis absorption spectra, and elemental analyses. Additionally, in this study, the oligomer composites were obtained using the carbon material (char) derived from the 450°C pyrolysis of waste polyethylene terephthalates. The conductivity measurements of the produced composites were determined at 24-h periods by doping with iodine vapor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The primary purpose of this study was to prepare a new type of silver-coated hollow glass microspheres and to make available this facility for the fabrication of thermally conductive polymeric composites based on ethylene–vinyl acetate (EVA) copolymer. Thermally conducting composites could be produced with a silver coating around the hollow glass microspheres, despite the low silver volume content. The experimental results are discussed and compared to various theoretical models. The thermal diffusivity and the specific heat of the composites were also characterized and are reported. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Composites based on multiwall carbon nanotubes (MWCNTs) and the block copolymer styrene-butadiene-styrene with two different contents of styrene have been investigated and their electrical conductivity and mechanical properties have been evaluated. The composites were prepared by a solution casting procedure, using a dispersant agent for the MWCNTs. Conductivity values of 10−4 and 1.6 S cm−1 have been obtained for samples containing 1 and 12 wt % of MWCNTs, respectively. The percolation threshold achieved for these systems was ∼0.25 wt %. According to dynamic mechanical analysis, the MWCNTs interact with both phases of the copolymers, acting as a reinforcement filler, whereas the dispersant agent acts as a plasticizer. However, it was shown that the reinforcing effect of the MWCNTs overcomes the latter, resulting in an overall improvement of mechanical properties of the composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Mesoporous silica nanoparticles (MCM-41) with an average diameter of ∼ 20 nm were synthesized by a sol-gel method using binary surfactant system. Polystyrene (PS) composites containing mesoporous silica nanoparticles were prepared by in situ polymerization of styrene monomers. Similar in situ polymerized PS composites were prepared based on the modified silica functionalized with methyl and vinyl groups. The effects of silylation on thermal and rheological properties of the PS/silica composites are investigated. Of particular importance is that the in situ polymerization of monomers within the mesoporous silica may trap some polymer chains, if not all, thereby affording a greater physical interaction between polymer and the porous fillers, whereas the chemical modification of silica surface promotes the polymer–filler interaction, which in turn enhances the thermal stability of composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Resol type resins were prepared in alkaline conditions (potassium hydroxide or potassium carbonate) using furfural obtained by acid hydrolysis of abundant renewable resources from agricultural and forestry waste residues. The structures of the resins were fully determined by 1H, 13C, and 2D NMR spectrometries with the help of four models compounds synthesized specially for this study. MALDI-Tof mass spectrometry experiments indicated that a majority of linear oligomers and a minority of cyclic ones constituted them. Composites were prepared with furfural–phenol resins and sisal fibers. These fibers were chosen mainly because they came from natural lignocellulosic material and they presented excellent mechanical properties. Thermal analyses (dTG and DSC) and electron microscopy images indicated that the composites displayed excellent adhesion between resin and fibers. Impact strength measurement showed that mild conditions were more suitable to prepare thermosets. Nevertheless, mild conditions induced a high-diffusion coefficient for water absorption by composites. Composites with good properties could be prepared using high proportion of materials obtained from biomass without formaldehyde. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Two different commercial crosslinked resins (Amberlite GT73 and Amberlite IRC748) were employed for anchoring silver. The SH and N(CH2COOH)2 groups, respectively, present on these resins were used for Ag 1 che- lation from an aqueous solution. The Ag 1 ions were reduced with three different reductants: hydrazine, hydrox- ylamine, and formaldehyde (under an alkaline pH). The produced composites were characterized with thermog- ravimetry/differential thermogravimetry and scanning ele- ctron microscopy combined with a backscattered scanning electron detector. Energy-dispersive X-ray spectroscopy coupled to scanning electron microscopy allowed the obser- vation of submicrometer particles of silver, and chemical microanalysis of emitted X-rays revealed the presence of metal on the internal and external surfaces of the composite microspheres. The amount of incorporated silver was deter- mined by titration. The antibacterial activity of the silver/ resin composites was determined toward 10 3 -10 7 cells/mL dilutions of the auxotrophic AB1157 Escherichia coli strain; the networks containing anchored submicrometer silver particles were completely bactericidal within a few minutes because of the combined action of silver and functional

Composites of linear low-density poly(ethylene-co-butene) (PE) or maleated linear low-density poly (ethylene-co-butene) (M-PE) and cellulose (CEL), cellulose acetate (CA), cellulose acetate propionate (CAP), or cellulose acetate butyrate (CAB) were prepared in an internal laboratory mixer with 20 wt % polysaccharide. The structure and properties of the composites were studied with tensile testing, dynamic mechanical thermal analysis, differential scanning calorimetry, extraction with a selective solvent, Raman spectroscopy, and X-ray diffraction. Composites prepared with M-PE presented yield stress and elongation values higher than those of composites prepared with PE, showing the compatibilizer effect of maleic anhydride. Dynamic mechanical thermal analysis performed for M-PE–CEL, M-PE–CA, M-PE–CAP, and M-PE–CAB composites showed one glass-transition temperature (Tg) close to that observed for pure M-PE, and for M-PE–CAP, another Tg lower than that measured for the polysaccharide was observed, indicating partial mutual solubility. These findings were confirmed by the extraction of one phase with a selective solvent, gravimetry, and Raman spectroscopy. X-ray diffraction showed that the addition of CEL, CA, CAP, or CAB had no influence on the lattice constants of PE or M-PE, but the introduction of the reinforcing material increased the amorphous region. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:402–411, 2007

Mechanical properties of wood plastic composites (WPCs) manufactured from sawdust and virgin and/or recycled plastics, namely high density polyethylene (HDPE) and polypropylene (PP), were studied. Sawdust was prepared from beech industrial sawdust by screening to the desired particle size and was mixed with different virgin or recycled plastics at 50% by weight fiber loading. The mixed materials were then compression molded into panels. Flexural and tensile properties and impact strength of the manufactured WPCs were determined according to the relevant standard specifications. Although composites containing PP (virgin and recycled) exhibited higher stiffness and strength than those made from HDPE (virgin and recycled), they had lower unnotched impact strengths. Mechanical properties of specimens containing recycled plastics (HDPE and PP) were statistically similar and comparable to those of composites made from virgin plastics. This was considered as a possibility to expand the use of recycled plastics in the manufacture of WPCs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3641–3645, 2006

Highly pure cellulose fibers were coated with polypyrrole (PPy) and subsequently used for preparation of composites, which reached a certain level of electrical conductivity. The cellulose fibers surface was entirely covered when 20 wt % of pyrrole was used for the modification, as confirmed by scanning electron microscopy (SEM). The cellulose fibers covered with PPy were kneaded with thermoplastic matrices: linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polycaprolactone (PCL). The highest electrical conductivity achieved was for composites based on the PCL matrix. PCL filled with 50 wt % of conducting cellulose fibers reached an electrical conductivity of 6.5 × 10−4 S cm−1. This electrical conductivity falls within the range required for antistatic materials. The mechanical properties of HDPE, LLDPE, and PCL matrices loaded with both treated and untreated cellulose fibers were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 133–142, 2006

Composites produced from biodegradable polymeric matrixes reinforced with vegetable fibers have attractive mechanical properties and are environmentally friendly. This work is directed to the biodegradation of a composite made of a poly(hydroxybuty- rate-co-hydroxyvalerate) matrix reinforced with curaua fibers (with and without alkaline treatment) in simulated soil. The composites were developed by extrusion and injection and were later buried in simulated soil according to the ASTM G160-03 method. Scanning electron microscopy showed evidence of microbial attack on the samples surfaces. Infrared spectra showed that the composites biode- gradation was mainly caused by erosion of the surface layer resulting from microorganisms activity. Thermogravimetric analysis pointed out reduced thermal stability of the samples, and results of differential scanning calorimetry showed that the degree of crys- tallinity increases and then decreases progressively throughout the degradation period, indicating that enzymatic degradation primar- ily occurs in the amorphous phase material and thereafter in the crystalline phase. For curaua composite fibers, reductions in tensile strength and elastic modulus are more significant, indicating that the presence of fibers promotes biodegradation of the curaua fiber. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40712.

The electrical response of thermoplastic composites composed of carbon black and high-density polyethylene near the electrical percolation threshold ( pc) has been investigated through the study of the volume resistivity and complex permittivity. The change in conductivity beyond pc exhibited a critical exponent that was greater than predicted from percolation theory. Composites with carbon black contents slightly larger than pc exhibited the greatest sensitivity in volume resistivity with temperature variations under the melting point of polyethylene. In addition, percolating composites with low carbon black contents exhibited significant "negative temperature coefficient" (NTC) effects and improvements in conductivity with annealing. Maxwell-Wagner interfacial polarization resulted in moderate increases in both the permittivity (e9) and dielectric loss factor (e0) below pc, while at percolation, an abrupt and dramatic increase was observed for both components of the complex permittivity. © 1999 John Wiley & Sons

The mechanical properties of glass-fiber-reinforced polystyrene composites were investigated with the variation of glass fiber content, surface treatment conditions, and silane coupling agents. γ-MPS, GPS, and poly(γ-MPS-co-stvrene) were used for the surface modification of glass fiber. Mechanical properties of glass-fiber-reinforced polystyrene composites increased with increasing the content of glass fiber. Poly(γ-MPS-co-styrene) was superior to γ-MPS and GPS in promoting the interfacial adhesion of glass fiber-reinforced polystyrene composites. The mechanical properties of composites were maximum at a low copolymer concentration when the γ-MPS content in the copolymer was high and vice versa. © 1996 John Wiley & Sons, Inc.

A blocked diisocyanate polyester was synthesized to copolymerize with novolak-type phenolic resin. From the results of IR and NMR spectra, it was found that the blocked diisocyanate polyester reacts with the hydroxyl group of the novolak-type phenolic resin at high temperature. The deblocking temperature for the novolak-type phenolic resin is 120°C. The blocking agent, e-caprolactam, is convenient for this system. The copolymer exhibited a single glass transition temperature and a negative deviation of the glass transition temperature. The results showed that the copolymer system is miscible and the molecular motion of the copolymer is increased with the addition of a modifier. The interface between the modified phenolic resin and the glass fiber is improved and the tensile strength of pultruded composite is increased with the modifier content. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1119–1127, 1998

This investigation focuses on the preparation of bio-based composites from recycled poly (ethylene terephthalate) (PET) and sisal fibers (3 cm, 15 wt %), via thermopressing process. Plasticizers derived from renewable raw materials are used, namely, glycerol, tributyl citrate (TBC) and castor oil (CO), to decrease the melting point of the recycled PET (Tm ∼ 265°C), which is sufficiently high to initiate the thermal decomposition of the lignocellulosic fiber. All used materials are characterized by thermogravimetric analysis and differential scanning calorimetry, and the composites are also characterized via dynamic mechanical thermal analysis. The storage modulus (30°C) and the tan δ peak values of CT [PET/sisal/TBC] indicate that TBC also acts as a compatibilizing agent at the interface fiber/PET, as well as a plasticizer. To compare different processing methods, rheometry/thermopressing and compression molding are used to prepare the recycled PET/sisal/glycerol/CO composites. These two different methods of processing show no significant influence on the thermal properties of these composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40386.

In this study, carboxylated acrylonitrile butadiene rubber (xNBR)/expanded graphite (EG) nanocomposites were prepared with a latex compounding technique by ultrasonic stirring. The dispersion of EG in the xNBR matrix was investigated with transmission electron microscopy, scanning electron microscopy, and X-ray diffraction analysis. EG could be exfoliated into lots of nanosheets dispersing in the xNBR matrix. More EG loading resulted in the presence of a few incompletely exfoliated agglomerates. The mechanical properties (hardness, tensile modulus, and tensile strength) of the xNBR/EG composites were determined. Dynamic mechanical thermal analysis was also performed, and it showed that the nanosheets of EG somewhat immobilized the motion of rubber macromolecular chains and led to the shifting and broadening of the tan δ peak toward higher temperatures. Many other functional properties of EG-filled xNBR composites were studied, and it was established that the composites had excellent electrical conductivity as well as gas-barrier and wear properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

For composites polypropylene–short glass fibers having different interface adhesion, correlation has been proved to exist between the morphology of fracture surfaces, the temperature dependence of impact strength, and the deformational and fracture behavior in tensile loading. The results are interpreted in terms of the mechanism of distortion plasticity for unfilled PP and for filled PP having weak interface adhesion, and on the basis of dilatation plasticity for filled polypropylene with a higher interface adhesion. The transition from the distortion to the dilatation mechanism can be seen in fracture surfaces after tensile destruction in composites possessing a higher interface adhesion.

The preparation and characterization of a biobased electromagnetic absorbing composites derived from natural lacquer as a renewable resource with microwave-absorption fillers, including Ni–Zn ferrite and carbonyl iron (CI) as magnetic metals and soot and carbon nanotube (CNT) as carbon materials, were investigated in terms of the gel content, hardness, drying properties, and electromagnetic absorption properties. Interestingly, composites with ferrite and CI contained up to 320 and 550 wt %, respectively, of these compounds. This quite high loading capacity of the metal fillers in a natural-lacquer base could have been due to the high compatibility between the filler and the natural lacquer; this indicated that the natural lacquer worked as a binder for these metals. The morphology of the biobased composite was characterized by scanning electron microscopy. The electromagnetic absorption properties of composites were characterized in the frequency range from 0.05 and 20 GHz by the reflection loss (RL) measurement method in terms of the kind of fillers and filler loading. The natural lacquer did not affect the absorption properties of the fillers. Biobased composites showed over 99% electromagnetic absorption in the frequency range 3.0–4.0 GHz for 280 wt % ferrite and 8.9–9.7 GHz for 200 wt % CI. Conversely, 10 and 20 wt % soot exhibited good performance (RL

Surface flame retarded jute/polypropylene composites (J/P/A) were prepared via a modified strategy: the mixture of PP and APP powder was spread over the surface of jute/PP nonwoven felts, and then transformed into the flame retarded layer by the hot pressing process. The flame retardancy and thermal properties of composites were analyzed by limit oxygen index (LOI), horizontal burning rate (HBR), thermogravimetric analyses (TGA), and differential scanning calorimetry (DSC). We demonstrated that the flame retardancy and mechanical properties of composites was significantly improved compared with those obtained by presoaking the nonwoven fiber felts in flame retardant (FR) solvent before hot pressing. The mechanism of thermal degradation of jute fiber and flame-retardant mechanism of composites were analyzed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscope (SEM). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43889.

A vinyl isocyanate (VI) synthesized from toluene diisocyanate and 2-hydroxyethyl methacrylate was used as a novel coupling agent to obtain strong chemical interfacial adhesion and therefore, improve the tensile properties of Kraft fiber-reinforced unsaturated polyester (UPE) composites. Results characterized by fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and scanning electron microscope (SEM) indicated that the novel coupling agent VI had a significant effect on the tensile properties of composites due to the formation of chemical bonds between the VI-Kraft interfaces and the VI-UPE interfaces. The tensile properties of composites modified by VI were much better than those of the control composite without VI modification. The VI-modified composites after severe hygrothermal aging exhibited lower losses of tensile properties and desirable tensile durability. The improvement in tensile properties, less interfacial separation after severe hygrothermal aging, lower damping values, and higher glass transition temperature are sufficient to show that the interfacial adhesion between the Kraft fiber and the UPE matrix was significantly improved because the coupling agent VI has both active isocyano groups which react with the Kraft fiber and vinyl groups which are copolymerizable with the UPE resin. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Recently, the natural fibers-reinforced composites have attracted substantial attention as a potential structural material for low cost applications. The composites of poly(lactic acid) (PLA) with three kinds of natural fibers, such as bamboo fibers, wood fibers, and coconut fibers (CTFs), were prepared by solution-casting technique. The natural fibers were modified by aluminum acid ester coupling agent and stearic acid to improve compatibility. To compare the mechanical and thermal properties of composites, tensile test, dynamic mechanical analysis, differential scan calorimeter, scanning electron microscopy (SEM), and Vicat softening point test were carried. The results showed that the addition of three kinds of natural fibers all could improve the mechanical and thermal properties of composites, and natural fibers after modification could further improve tensile strength of composites. And in comparison, the composite of PLA/CTF had highest tensile strength and best thermal properties. When the content of natural fibers were 2%, the highest tensile strength of PLA/modified CTF composites was highest, and it reached 22.5 Mpa which was 20.4% higher than that of pure PLA, and VST of this composite increased compared with pure PLA. Meanwhile, the results of SEM indicated that the modified CTF had best interfacial compatibility to PLA. These results indicated that PLA/natural fiber composites had higher strength and better heat resistance than pure PLA. This study provided the application of PLA industry with a feasible method. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

In this study, rice-straw (RS) filled high density polyethylene (HDPE) composites were manufactured by extrusion and injection molding. Three compatibilizers, which are unfunctionalized ethylene/propylene copolymer (uEPR), maleic anhydride grafted EPR (EPR-g-MA) and PE-g-MA, and their combinations were introduced to strengthen fiber-matrix interphase. The mechanical and morphological properties of composites were investigated. For single-compatibilizer system, PE-g-MA or EPR-g-MA alone enhanced tensile, flexural, and impact strengths of resultant composites compared with HDPE/RS system without compatibilizers. Different toughening origins of individual compatibilizer were discussed based on composites' interphase morphologies and mechanical properties. For combined-compatibilizers system, the PE-g-MA/EPR weight ratio is important for several properties of composites. The optimum ratio was considered as 2 : 1 and 1 : 1 for PE-g-MA/uEPR and PE-g-MA/EPR-g-MA modified composites, respectively. Also, composites modified by combined PE-g-MA/EPR-g-MA showed better impact strength than that modified by PE-g-MA alone. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

In this article, a series of polyurethane (PU)/organic vermiculite (OVMT) composites are prepared by intercalating polymerization. 1,4-cyclohexane diisocyanate (CHDI) as hard segment of PU is designed to improve the decomposition temperature of composites. Vermiculite (VMT) is modified by method of cation exchange with octadecyl trimethyl ammonium bromide (OTAB); the resulting product OVMT with the function of physical cross-linking disperses well in soft segment of PU polycarbonate polyol (PCDL), which improves the mechanical properties of composites obviously. This modification further enlarged the interlayer of OVMT and improved the properties of composites. The structure and properties of OVMT and PU/OVMT composites are characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscope, and tensile strength test. The results showed that the layer spacing of OVMT increased 1.41 nm compared with that of VMT (the value of layer spacing of VMT is 0.96 nm) and further enlarged to 2.92 nm by the loading of PCDL. The tensile strength and the strain at break of PUCPB/OVMT (3.0%) composites reached 26.8 MPa and 443%, respectively. The temperature resistance of PUCPB/OVMT (3.0%) composites is above 300°C, which is more suitable for the steam channeling plugging of heavy oil. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43219.

Flyash, a waste product of thermal power stations, generated in huge quantities, has been posing problems of disposal. Attempts have been made for its utilization as a filler in elastomers and plastics; however, it has been established that untreated flyash does not at all contribute in enhancing mechanical properties of composites. The purpose of this work was to make meaningful utilization of flyash as a filler, by treating it with a titanate coupling agent and to use it as a filler in PBR. The properties under consideration were tensile strength, modulus at 100 and 400%, Young's modulus, hardness, etc. Composites were made with varying proportion of untreated and treated flyash. A two-roll mill was used for dispersing the filler in the rubber, and a compression-molding technique was used to cure the compound in sheet form. Tensile properties were measured on a computerized UTM using an ASTM procedure. Comparison of properties of composites filled with treated and untreated flyash established that treatment of flyash imparts better reinforcing properties. Tensile strength was improved by 50%, while modulus at 400% was improved by 400%. Similarly, Young's modulus also was improved by 209%. The Titanate-coupling agent used here has promoted adhesion between flyash and the PBR. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1293–1298, 2004

Fly ash, a waste productof thermal power stations generated in huge quantities, has been posing problems of its disposal. As such it contains a variety of inorganic oxides and is available in finely powdered form. Attempts have been made for its use as a filler in elastomers and plastics. It is important to note that fly ash used in in untreated form does not significantly enhance the mechanical properties of composites. In this work, fly ash treated with silane coupling agent (Si-69) was used as a filler in polybutadiene rubber (PBR). The comparison of properties of composites filled with treated and untreated fly ash revealed that the composites with treated fly ash showed better reinforcing properties. Thus the silane coupling agent used here promoted adhesion between fly ash and the PBR. The improvement in mechanical properties in general and tensile properties (tensile strength, modulus 100% and modulus 200%, hardness) of the composites in particular were observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1322–1328, 2004

The present study reports results on the processing and mechanical properties of composites modified by the addition of dicumyl peroxide (DCP). The addition of minute amounts of peroxide to the cellulose/polymer system during processing has been shown to significantly improve the physical properties of composites. SEM micrographs of fracture surfaces of the peroxide modified composites reveal direct grafting of polyethylene onto cellulose fibers. The existence of a critical peroxide concentration indicates that the grafting reactions terminate when cellulose surfaces are no longer accessible. Possible mechanisms involved are discussed.

A general mixture rule, which has the correct type of phase symmetry, is proposed for estimating the properties of composites having two continuous phases. The form of this equation is different from the equations used to predict the properties of composites with one continuous phase and one dispersed phase. The proposed equation for property P is where the volume fractions of components A and B are oA and oB, respectively, and n is a constant. A simple model is used to correlate the morphology of systems having two continuous phase with the parameter n of the mixture rule. The connectivity of the phase varies with concentration. The properties, such as elastic modulus, depend primarily upon the modulus of the material with the higher modulus. In general, the properties depend very little on the morphology of the system.

The strength properties of composites made of untreated cellulose fibers and linear low density polyethylene were investigated as a function of processing parameters. Studies have shown that the strength properties of composites increase with processing time and temperature. The increase in strength is accompanied by the appearance of new infrared absorption bands at 1718 and 1735 cm−1. A linear relationship between the absorbance and yield strength of composites indicates that oxidation, possibly directly at interfaces, takes place and enhances adhesion between the cellulose and polyethylene.

Composites were investigated regarding the comparison of multi-walled carbon nanotubes (MWCNTs) with exfoliated graphene(EG) in poly(L-lactic acid) (PLLA) and the effect of silane-treated carbon nanofillers on properties of PLLA composites. So- lution blending method was used to prepare PLLA composites at a filler content of 0.5 wt %. Fourier transform infrared spectroscopy and X-ray photoelectron spectra results indicated the attachment of silane molecules on the surface of these nanofillers. It was found that the addition of these nanofillers greatly enhanced the mechanical, thermomechanical, and crystallization behaviors of PLLA due to the heterogeneous nucleation effect. Moreover, the silane-treated fillers further enhanced the breaking elongation moderately (although the materials are still brittle), modulus and thermal property of the nanocomposites, without sacrificing the tensile strength, compared with the pristine nanocomposites. On the other hand, composites reinforced with MWCNTs and EG perform almost the same mechanical property. And EG outperformed MWCNTs in thermomechanical properties of composites when being used as the reinforcement of PLLA. Conversely, composites reinforced with MWCNTs showed better crystallization properties than those reinforced with EG. Interestingly, no significant changes were observed for the crystallization properties of PLLA composites when MWCNTs and EG had been treated by silane coupling agent. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1194-1202, 2013

The influence of highly degraded high-density polyethylene (HDPE) on physical, rheological, and mechanical properties of HDPE-wood flour composites was studied. For this purpose, the virgin HDPE was subjected to accelerated weathering under controlled conditions for 200 and 400 h. The virgin and exposed HDPE and pine wood flour were compounded to produce wood flour-HFPE composites. The results showed that the accelerated weathering highly degraded HDPE. Degradation created polar functional carbonyl groups and also produced extensive cross-linking in HDPE and consequently poor processibility. The interruptions in the flow characteristics of the degraded HDPE potentially caused processing hurdles when using them for extrusion or injection molding manufacturing as only small part (10%) of virgin HDPE could be replaced by highly degraded HDPE for wood flour-HDPE composite manufacturing. The mechanical properties of composites containing highly degraded HDPEs were similar to the composites with virgin HDPE and in some cases they exhibited superior properties, with the exception being with the impact strength. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Poly(dodecafluoroheptyl methacrylate) (PDFMA)/titanium dioxide (TiO2) nanocomposites with high TiO2 content were successfully prepared by emulsion polymerization process. Before polymerization, nano-TiO2 was pretreated by silane coupling agent. Surface groups and composition of the modified nano-TiO2 were characterized by Fourier transform infrared and X-ray photoelectron spectra. The microstructure of nanocomposites was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the thermo-stability and wetting behavior were also investigated in relation to the dosage of TiO2. The results showed that the thermostability is improved with the increment of TiO2 content while hydrophilic properties exhibit nonlinear variation with the content of TiO2. The optimal percentage of TiO2 content in the TiO2/PDFMA nanocomposites is 30% that could lead to the higher thermostability and hydrophobicity properties of composites. The maximum water contact angle (WCA) of nanocomposites can reach 120° ± 1°. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44377.

Graphene oxide (GO), as an important precursor of graphene, was functionalized using alkyl-amines with different structure and then reduced to prepare reduced amines grafted graphene oxide (RAGOs) by N2H4 · H2O. The successful chemical amidation reaction between amine groups of alkyl-amines and carboxyl groups of GO was confirmed by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA). Then RAGOs/polyimide nanocomposites were prepared via in situ polymerization and thermal curing process with different loadings of RAGOs. The modification of amine chains lead to homogenous dispersion of RAGOs in the composites and it formed strong interfacial adhesion between RAGOs and the polymer matrix. The mechanical and electrical properties of polyimide (PI) were significantly improved by incorporation of a small amount of RAGOs, the influence of structure of amines grafted on RAGOs on the enhancement effects of composites was discussed. The research results indicated that the proper structure of amine could effectively enhance the properties of composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43820.

In this research, the reinforcing effect of fillers including canola stalk, paulownia and nanoclay, in polypropylene (PP) has been investigated. In the sample preparation, 50 wt% of lignocellulosic materials and 0, 3, and 5 wt% of nanoclay particles were used. The results showed that while flexural and tensile properties were moderately enhanced by the addition of nanoclay in the matrix, notched Izod impact strengths decreased dramatically. However, with increase in the nanoclay content (5 wt%), the flexural and tensile properties decreased considerably. The mechanical properties of composites filled with paulownia are generally greater than canola stalk composites, due to the higher aspect ratio. The thickness swelling and water absorption of the composites significantly decreased with the increase in nanoclay loading. Except tensile modulus, the differences between the type of fibrous materials and nanoclay contents had significant influence on physicomechanical properties. Morphologies of the composites were analyzed using transmission electron microscopy (TEM) and X-ray diffraction (XRD), and the results showed increased d-spacing of clay layers indicating enhanced compatibility among PP, clay, and lignocellulosic material. TEM micrographs also confirmed that the composites containing 3 wt% nanoclay had uniform dispersion and distribution of clay layers in the polymer matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Composites were prepared from poly(butylene succinate) (PBS), lignin, and switchgrass using extrusion followed by injection molding techniques. The effects of the fillers (lignin and switchgrass) and polymeric methylene diphenyl diisocyanate (PMDI) compatibilizer on the physicomechanical and thermal properties of the composites were investigated. Use of hybrid filler (1 : 1 lignin : switchgrass) resulted in slight improvement in the flexural strength of the composites. Incorporation of 1% PMDI into the hybrid filler reinforced composites significantly enhanced properties compared with the neat PBS which accounts for improvements in the flexural strength, flexural modulus, and heat deflection temperature (HDT) by nearly 165%, 375%, and by 24°C respectively. Lignin exhibited some effects on the thermal properties of composites. However, switchgrass demonstrated a minor effect on the thermal behavior of the composites compared with the lignin. An improved interface was observed from the scanning electron microscopy (SEM) of the compatibilized hybrid composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Poly(melamine-urea-formaldehyde) (MUF) microcapsules used as self-healing component of composites were prepared by in situ polymerization. The surface of MUF microcapsules was modified by 3-aminopropyltriethoxy silane-coupling agent (KH550). The interfacial interactions between MUF microcapsules and KH550 were studied by Fourier transform infrared spectra (FTIR). FTIR results show that the silane-coupling agent molecule binds strongly to the MUF microcapsules surface. A chemical bond (SiOC) is formed by the reaction between the SiOH and the hydroxyl group of MUF microcapsule. This modification improves the thermal properties of microcapsules. Optical microscope (OM) and scanning electron microscope (SEM) show that a thin layer is formed on the surface of MUF microcapsules. The interfacial adhesion effect between MUF microcapsules and unsaturated polyester matrix was investigated. MUF microcapsules disperse evenly in the composites. When crack propagated, the microcapsules were broken and the repair agent flowed from the microcapsules to react with the curing agent. Then the crosslinking structure was formed and the composite was repaired. The tensile properties, impact properties, and dynamic mechanical properties of composites have been evaluated. The results indicate that the silane-coupling agent plays an important role in improving the interfacial performance between the microcapsules and the matrix, as well as the mechanical properties of the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Effects of alkalization, esterification, and γ-irradiation of wood on the transcrystalline morphology of wood/polypropylene composites were investigated using X-ray diffraction, hot stage optical microscopy, and scanning electron microscopy. The occurrence of transcrystallization in wood-polypropylene composites is strongly dependent on the type of chemical modification of lignocellulosic materials. A detailed analysis of the results obtained proved that the transcrystallization is strongly influenced by conditions of mercerization process of wood and kind of anhydrides. Moreover, it has been found that amount of cellulose in wood plays a key role in the development of transcrystallinity. The absence of cellulose in wood seems to be unfavorable for the growth of transcrystallinity. A relationship between mechanical properties of composites and the phenomena taking place at the polymer-filler interface, controlled by chemical modifications of lignocellulose components has been evaluated. It has been established that the mechanical properties of wood composites depend on the proper choice of a modifier and are obtained after optimization of the process of modification. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Nano-calcium carbonate (nano-CaCO3) was used in this article to fill acrylonitrile–butadiene–styrene (ABS)/poly(methyl methacrylate) (PMMA), which is often used in rapid heat cycle molding process (RHCM). To achieve better adhesion between nano-CaCO3 and ABS/PMMA, nano-CaCO3 particles were modified by using titanate coupling agent, aluminum–titanium compound coupling agent, and stearic acid. Dry and solution methods were both utilized in the surface modification process. ABS/PMMA/nano-CaCO3 composites were prepared in a corotating twin screw extruder. Influence of surface modifiers and surface modification methods on mechanical and flow properties of composites was analyzed. The results showed that collaborative use of aluminum–titanium compound coupling agent and stearic acid for nano-CaCO3 surface modification is optimal in ABS/PMMA/nano-CaCO3 composites. Coupling agent can increase the melt flow index (MFI) and tensile yield strength of ABS/PMMA/nano-CaCO3 composites. The Izod impact strength of composites increases with the addition of titanate coupling agent up to 1 wt %, thereafter the Izod impact strength shows a decrease. The interfacial adhesion between nano-CaCO3 and ABS/PMMA is stronger by using solution method. But the dispersion uniformity of nano-CaCO3 modified by solution method is worse. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Nanocomposites of polypropylene and graphene nanoplatelets were synthesized by in situ polymerization in liquid monomer in the presence of highly effective isospecific homogeneous metallocene catalyst. Microstructure, mechanical, dielectric, and thermal properties of composites are presented. X-ray phase analysis data indicate that graphene nanoplatelets are present in composites as thin flaky particles aggregates, with aspect ratio affected by sonication of reaction mixture. Crystallization tempera- ture of polypropylene increases in composites. Nanocomposites are characterized by high rigidity, thermal stability, and crystalliza- tion temperature, low conductivity, and high dielectric losses in the microwave range. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 904-911, 2013

Carbon nanotubes (CNTs), with their high aspect ratio and exceptionally high mechanical properties, are excellent fillers for composite reinforcement if they are uniformly dispersed without aggregation. Combining the latex compounding and self-assembly techniques, we pre- pared a novel natural rubber (NR)/multiwalled carbon nanotube (MWCNT) composite. Before self-assembly, the MWCNTs were treated with mixed acid to ensure that the MWCNTs were negatively charged under an alkaline envi- ronment. The structure of the MWCNTs was tested with Fourier transform infrared spectroscopy. The properties of composites with different MWCNT loadings were charac- terized with transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, and tensile testing. The results indicate that the MWCNTs were homogeneously distributed throughout the NR matrix as single tubes and had good interfacial adhesion with the NR phase when the MWCNT loading was less than 3 wt %. In particular, the addition of the MWCNT led to a remarkable reinforcement in the tensile strength, with a peak value of 31.4 MPa for an MWCNT content of 2 wt %, compared to the pure prevulcanized NR (tensile strength ¼ 21.9 MPa). The nanocomposites rein- forced with MWCNTs should have wide applications because of the notable improvement in these important properties. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 125: 3920-3928, 2012

In this article, we report the mechanical and thermal properties, together with the crystallization and flammability behaviors, of pure polypropylene (PP) and PP/aramid fiber (AF) composites with AF loadings of 5, 10, 20, 30, and 40 wt %. The mechanical properties of the samples were evaluated by tensile and izod notched impact tests, and the results show that the tensile strength of the composites could reach up to 67.8 MPa and the izod notched impact strength could rise to 40.1 kJ/m2. The structure and morphology were observed by scanning electron microscopy and polarized optical microscopy, respectively. This demonstrated that a solid interface adhesion between the matrix and fibers was formed. The thermal and crystalline behaviors of the PP/AF composites were also investigated by thermogravimetric analysis and differential scanning calorimetry analysis, and the results show that the char residue of the PP/AF composites improved greatly with increasing AF loading, and the highest value could reach up to 23.7% in the presence of 40 wt % AF. The supercooling degree, initial crystallization temperature, and crystallization percentage were used to characterize the crystallization behavior of the PP/AF composites, and the results indicate that the AFs had positive effects on the promotion of PP nucleation, which can usually improve the mechanical properties of composites. Moreover, the flammability analysis of the PP/AF composites demonstrated that the presence of AFs could significantly decrease the peak heat release rate and the total heat release and reduce the melt-dripping of the PP/AF composites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Extruded/injection-molded composites of excellent mechanical property were produced from plantain flour (PF) blended with ethylene–vinyl alcohol (EVA) and glycerol. Scanning electron microscopy (SEM) revealed that composites had a smooth surface, indicative of an excellent compatibility between PF, EVA, and glycerol. Generally, tensile strength (TS), elongation at break (%E), and the displacement (DM), all decreased with increased PF content in the composite accompanied by an increase in Young's modulus (M). The composites with higher PF contents (60% or higher) had more stable mechanical properties. Selected composites (60% PF content) stored at −20°C and 4°C for 40 h showed only minor changes in mechanical properties compared with controls (23°C). However, samples stored for a similar period at 80°C were drastically altered in their mechanical properties resulting in huge increases in TS and M and a 10-fold decrease in the %E. Samples prestored at various relative humidities (RHs) for 40 h exhibited only slight decrease in TS and M and a concomitant increase in the %E with increased RH. Interestingly, sample prestored at both −20°C and 80°C exhibited significantly higher rates and extents of degradation. SEM analysis of samples left in compost for 8 weeks showed a rapid surface erosion and material deterioration with time. Evaluation of the color produced during heat processing of starch in PF as a result of Maillard reaction showed an increase in the values of luminosity (L*), chroma (C*), and hue angle (h*) with decreased PF content in the composite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

In this study, the effect of oil fly ash (OFA), a by-product of oil fuel power plants, on the rheological and morphological behavior of low-density polyethylene (LDPE) is investigated. As received and acid-functionalized OFA (COOH-OFA) are used to examine the effect of surface modification of OFA on polymer-filler composites. LDPE/OFA composites were prepared by melt mixing with filler loading in the range 1-10 wt %. The results are compared with pure LDPE. The effect of polyethylene-grafted-maleic anhydride (PE- g-MA) as a compatibilizer was also studied. Both vis- cous and elastic properties of composites increased with OFA loading especially at low frequency. The surface modification of OFA has influenced the properties of OFA. As-received OFA showed some agglomeration at high loading that resulted in two-phase system as described by scanning electron microscopy (SEM) and Cole-Cole plot. Field emission-SEM (FE-SEM) images showed improvement in the dispersion of COOH- LDPE/OFA composites. In addition, the surface modifi- cation reduced the size of agglomeration. In general, the COOH modification of OFA improved both the disper- sion and rheological properties of OFA. With chemical modification, the concentration of the filler can be increased to 10% without compromising the properties of the composites. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2486-2496, 2011

Highly electrically conductive polypropylene (PP) composites were prepared by melt mixing using tin–lead (Sn-Pb) alloy as conducting fillers. Two Sn-Pb alloys, Sn-Pb (20/80) and Sn-Pb (40/60), were used for comparison. The effects of Sn-Pb loading and molding temperature on electrical conductivity and mechanical properties of composites were investigated. It was found that both factors had significant effect on electrical conductivity of the final Sn-Pb/PP composite. It was interesting to observe that the molding temperature could control the formation of long-range conducting paths. The mechanism has been explored through the nonequilibrium phase behavior of Sn-Pb alloy. The influence of Sn-Pb loading on mechanical properties of Sn-Pb/PP composites was also investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A new type of layered zirconium phosphonate (zirconium glycine-N, N-dimethylphosphonate, abbreviated as ZGDMP), with functional group of -COOH, has been successfully prepared and characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). To confirm the effect of the functional group -COOH on the structure and properties of composites, a series of chitosan/zirconium phosphonate modified by n-butylamine (BA-ZGDMP) nanocomposite films were prepared by casting process. FTIR spectra suggested that strong interactions existed between BA-ZGDMP and chitosan matrix. Compared to neat CS film, tensile strength (σb) and elongation at break (eb) of the nanocomposite film improved by 35.1% and 15.6%, respectively, with loading ratio of just 1.0 wt %. In addition, the BA-ZGDMP also improved the water resistance of the nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The purpose of this research was to investigate the water absorption behavior and associated dimensional stability of kenaf-polypropylene-filled (PP/KF) composites. Composites with different fiber loadings, ranging from 0 to 40 wt %, were prepared with a twin-screw extruder followed by hot press molding. The influence of the compatibilizer was also studied for PP/KF composite with 5 wt % maleated PP (MAPP). Water absorption testing was carried out at room temperature for 7 weeks. Tensile, flexural, and impact tests were also performed on control, wet, and re-dried specimens. Increasing the fiber content resulted in higher water absorption and thickness swelling. The inferior mechanical properties of the wet composites were attributed to the effect of water, which deteriorates the interfacial properties of composites. On re-drying, all properties were almost recovered because of the recovery of interfacial area as evident in scanning electron micrographs. Incorporation of the MAPP significantly improved the compatibility between the fiber and matrix and the mechanical properties of the composites compared with those without MAPP. It also diminished the water absorption as well as the related thickness swelling in the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010