Toughening and compatibilization of polypropylene/polyamide‐6 blends with a maleated–grafted ethylene‐co‐vinyl acetate

In this article, maleated–grafted ethylene‐co‐vinyl acetate (EVA‐g‐MA) was used as the interfacial modifier for polypropylene/polyamide‐6 (PP/PA6) blends, and effects of its concentration on the mechanical properties and the morphology of blends were investigated. It was found that the addition of EVA‐g‐MA improved the compatibility between PP and PA6 and resulted in a finer dispersion of dispersed PA6 phase. In comparison with uncompatibilized PP/PA6 blend, a significant reduction in the size of dispersed PA6 domain was observed. Toluene‐etched micrographs confirmed the formation of interfacial copolymers. Mechanical measurement revealed that the addition of EVA‐g‐MA markedly improved the impact toughness of PP/PA6 blend. Fractograph micrographs revealed that matrix shear yielding began to occur when EVA‐g‐MA concentration was increased upto 18 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99:3300–3307, 2006     

Tuning the nano/micro‐structure and properties of melt‐processed ternary composites of polypropylene/ethylene vinyl acetate blend and nanoclay: The influence of kinetic and thermodynamic parameters

The present study reports the dependence of the nano/micro‐structure and properties of polypropylene (PP)/ethylene vinyl acetate (EVA)/nanoclay ternary composites on the kinetics and thermodynamics of the melt‐mixing process. The size of dispersed EVA particles in the blends increased in the presence of the nanoclay particles, whereas in the ternary blend composites the size of the EVA dispersions decreased with increasing processing time. Intercalation and exfoliation were achieved more efficiently in ternary composites prepared with a longer EVA processing time. Moreover, the incorporation of the nanoclay particles within the EVA phase and interphase, as well as a long processing time stabilized the morphology. The degree of crystallinity, melting behavior, and crystallization temperature of PP in the ternary composites were not influenced by the presence of the nanoclay particles or by the duration of the melt‐mixing process. The thermal stability of the ternary composites improved with increasing melt‐mixing time. The rheological and thermomechanical properties were found to be dependent on the processing time and on the resulting structure. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45585.     

High performance polyamide 6 composites prepared by reactive extrusion

To improve the properties of polyamide 6 (PA6) composites, a series of modified PA6 composites was prepared by reaction extrusion. An amorphous PA6 was first obtained by the complexing reaction of Li⁺ in lithium chloride with amino groups, and then epoxy resins, nano‐SiO₂ as well as POE‐g‐MAH were in turn added into the PA6/LiCl system. The effect of different additives on the crystallization behavior and mechanical properties of PA6 composites was well‐studied by X‐ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and mechanical properties tests. The results demonstrated that PA6 was amorphous at 6 phr lithium chloride and a network structure was formed in PA6 matrix in the presence of epoxy resins, thus the mechanical properties of composites greatly were enhanced. However too many nano‐SiO₂ particles might impair the tensile strength of PA6 composites. Additionally, a PA6 composite with excellent properties was obtained in the presence of POE‐g‐MAH due to the crystal form change in PA6 matrix and the strong interaction between PA6 and POE‐g‐MAH. POLYM. COMPOS., 35:985–992, 2014. © 2013 Society of Plastics Engineers     

Comparative study of the tribological properties of polyamide 6 filled with molybdenum disulfide and liquid crystalline additives

The effect of adding a 1 wt % proportion of thermotropic liquid crystals 4,4′‐dibutylazobenzene (LC1) and 4‐octyl, 4′‐cyanobiphenyl (LC2) on the tribological properties of polyamide 6 (PA 6) is compared with that of the addition of MoS₂ in different concentrations (1 and 5 wt %). Friction and wear are determined in a pin‐on‐disk tribometer by using injection‐molded additivated nylon disks against steel or aluminum pins, below (25°C) and above (80°C) glass transition temperature. Polymeric blends are characterized by differential scanning calorimetry and by optical and scanning electron microscopy and microanalysis. Concentration of liquid crystalline additives is higher at the surface than in the bulk of PA 6 disks. Crystallinity degree of PA‐6 is not significantly changed by the presence of additives. Addition of 1 wt % LC1 improves processibility of PA 6 by increasing its melt flow rate. Cyanoderivative liquid crystal (LC2) shows the best wear‐reducing ability for PA 6/steel contacts at all temperatures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2426–2432, 2001     

Coloring effect of the organic hybrid of polyamide 6 and N,N′‐ethylene‐bis(tetrabromophthalimide)

Coloring study in organic hybrid of polyamide (PA6) and N,N′‐ethylene‐bis(tetrabromophthalimide) (EPT), where the chromophore was self‐assembled by hydrogen bonding formed between PA6 molecular chains and EPT compound, have been characterized by several techniques. CS930 double wavelength lamella scanner was employed to measure the change of color. The existence of hydrogen bonding in PA6/N‐N′‐ethylene‐bis (tetrabromophthalimide) (PA6EPT) was investigated with Fourier transform infrared (FTIR), the results of which were compared with that of PA6 with the same thermal history. FTIR spectra at room temperature revealed that there is essentially hydrogen bonding between PA6 and EPT. The crystallization behavior of PA6EPT affected by hydrogen bonding was studied by using FTIR. The temperature‐dependent behavior of both PA6 and PA6EPT was studied by temperature‐FTIR spectroscopy and differential scanning calorimetry (DSC). With temperature increasing, changes in sensitive, high‐resolution absorbance spectra are observed as dissolve‐volatilizing thin film. Temperature‐FTIR results showed that the hydrogen bonding in PA6EPT attenuated and dissociated considerably at a smaller rate than PA6, that is to say, hydrogen bonding in PA6EPT is more stable than that in PA6. DSC showed that the melting temperature of PA6EPT and PA6 are similar. However, the crystalline degree and crystalline temperature and melting enthalpy of PA6 and PA6EPT are different. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 594–600, 2007     

Effect of syndiotactic polystyrene on the crystallization behavior of isotactic polypropylene/syndiotactic polystyrene blends with and without β‐nucleating agent

Blends of isotactic polypropylene (PP) and syndiotactic polystyrene (sPS) with and without β‐nucleating agent were prepared using a twin‐screw extruder at 290 °C. Blends of PP/sPS with β‐nucleating agent mainly show β crystalline form, irrespective of high (20 °C min^?1) or low (2 °C min^?1) previous cooling rates. This suggests that the cooling rates have little effect on the polymorphic composition of PP in PP/sPS blends. The effect of sPS on the crystallization of PP is compared with that of polyamide 6 (PA6). The increase in crystallization temperature of PP is smaller in the presence of sPS than in the presence of PA6; the fold surface free energy of PP/sPS is larger than that of PP/PA6 blends. These results reveal that compared with PA6, sPS has much weaker α‐nucleation effect on the crystallization of PP. The weak α‐nucleation effect of sPS is attributed to the high lattice mismatch between PP and sPS crystals.     

Effect of dendrimer‐like PAMAM grafted attapulgite on the microstructure and morphology of Nylon‐6

The effect of dendrimer‐like polyamidoamine grafted attapulgite (ATP‐PAMAM) on the microstructure and morphology of Nylon‐6 (PA6) was investigated. The ATP‐PAMAM nanoparticles were prepared by treating attapulgite (ATP) with heat and acid followed by grafting with polyamidoamine (PAMAM) molecules, which was confirmed by Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), and dispersion state in formic acid. The X‐ray diffraction (XRD) analysis result indicated that the grafting modification was occurred on the surface of fibrous crystals and did not shift the crystal structure of ATP. PA6/ATP‐PAMAM (G_2.0) nanocomposites with different modified ATP content were prepared by melt compounding in a twin screw extruder. XRD measurements suggested that the intensity of diffraction peak of α crystalline form of PA6 decreased gradually as the inclusion of ATP‐PAMAM(G_2.0) into the PA6 matrix, while that of γ crystalline form increased gradually. The results of molau experiment and scanning electron microscopy (SEM) observation showed not only a uniform dispersion of ATP‐PAMAM(G_2.0) in the PA6 matrix but also a strong interfacial adhesion between them. Mechanical investigation (by tensile test) showed an obvious improvement in the presence of surface modified ATP. POLYM. COMPOS., 35:627–635, 2014. © 2013 Society of Plastics Engineers     

Toughening of polyamide‐6 with little loss in modulus by block copolymer containing poly(styrene‐alt‐maleic acid) segment

Toughening of polyamide‐6 (PA6) by elastomers without sacrificing the modulus of blends has always been a challenge. In this study, PA6 was modified by poly(styrene‐alt‐maleic acid)‐block‐polystyrene‐block‐poly(n‐butyl acrylate)‐block‐polystyrene tetrablock copolymer (BCP) elastomer. The introduced acid groups in BCP resulted in the size of BCP inclusions down to nanometers in polyamide matrix. 10 wt % of BCP‐modified PA6 blends achieved five times increase in notched impact strength with almost no loss in modulus. Microscopic observations suggested the cavitation of elastomer particles and shear yielding of PA6 matrix to be the major toughening mechanism. This research provides a strategy to toughen polyamides by block copolymers at very low rubber content. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44849.     

Morphology and properties of PBT/nylon 6/EVA‐g‐MAH ternary blends prepared by reactive extrusion

Morphology and properties of poly(butylene terephthalate) (PBT)/nylon 6 (PA6)/EVA‐g‐MAH ternary blends were investigated. The blends were prepared in a corotating, intermeshing, twin‐screw extruder. The incorporation of maleic anhyride (MAH) grafted onto ethylene‐vinyl acetate copolymer (EVA) (EVA‐g‐MAH) in the PBT/PA6 binary blends decreased the tensile and flexural strength but increased the impact strength, while the mechanical properties of the PBT/PA6 blends were decreased with increasing PA6 content regardless of the presence or absence of the EVA‐g‐MAH. The morphology studies of the ternary blends showed gross phase separation. The rheological properties of the ternary blends suggested that excessively high reactivity between amine end groups of PA6 and MAH grafted onto EVA makes the compatibility between PBT and PA6 worse, although EVA‐g‐MAH was expected to work as a compatibilizer for PBT/PA6 blends. The degree of reactivity between functional groups in PBT, PA6, and EVA‐g‐MAH was also examined by investigating the effect of blending sequence on the properties of the ternary blends.     

The formation of fibrous structure of polyamide 6 induced by the three-step forming process and its prominent reinforcement in nitrile rubber

Nitrile rubber (NBR) blends with excellent performance have always been a hot research topic in petroleum field. Due to the excellent performance and compatibility of polyamide 6 (PA6), it provides an opportunity for the preparation of high-performance NBR/PA6 blends. In this article, NBR/PA6 blends were prepared by the three-step molding process. Experimentally, it was found that PA6 has a prominent reinforcement effect in NBR matrix. The variation of this mechanical property was investigated from different aspects of the crystal structure, crystallinities, phase morphology, and so on. It can be cleared that the formation of fibrous structure of PA6 phase is the main factor for reinforcement of the polymer blends. Meanwhile, the formation mechanism of the special phase structure induced by the three-step process is deeply expounded and its structural evolution schematic is established. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47472.     

The observation of PP/EVA blends in which isotactic PP was preradiated with different radiation absorbed doses

Isotactic polypropylene (PP) was preradiated by γ ray with different absorbed doses and subsequently blended with ethylene‐vinyl acetate (EVA) co‐polymer to prepare PP/EVA blends. The average molecular weight (M_n) of isotactic PP decreased with the increasing radiation absorbed dose, which indicated that high energy radiation of γ ray broke the isotactic long PP chains into shorter ones. The melt flow rate results evidenced that the processing ability of PP/EVA blends was continuously promoted with the increasing absorbed dose. The β crystal was obtained in the PP/EVA blends by the radiation method. The onset temperatures and peaks of crystallization of PP/EVA blends decreased slightly with the increasing radiation absorbed dose, while high energy radiation was inclined to enhance the crystallinity of PP/EVA blends. The Fourier transform infrared spectroscopy (FTIR) tests confirmed an interesting phenomenon that PP tended to move to the surface of the PP/EVA blends with the increasing radiation absorbed dose. Mechanical tests proved that the PP/EVA blends remained a comparative stable mechanical property under the absorbed dose of 30 kGy. The experimental results indicated that PP/EVA blend was a potential candidate for industrial applying. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45057.     

High‐temperature copolyamides obtained by the efficient transamidation of crystalline–crystalline polyamide blends

High‐performance thermoplastic composites based on semiaromatic polyamides are prime candidates for metal replacement in lightweight structural applications. However, the low ductility and toughness of semiaromatic polyamides remain major obstacles to their wider industrial application. In this study, we showed that novel random copolymers were formed by the unexpectedly efficient transamidation during the melt compounding of semicrystalline semiaromatic and aliphatic polyamides. Thus, homogeneous materials with a single glass transition and a high degree of crystalline order were obtained from blends of the semiaromatic poly(hexamethylene terephthalamide‐co‐isophthalamide) (PA6TI) with poly(hexamethylene adipamide) (PA66) or poly(hexamethylene sebacoamide) (PA610). By contrast, phase segregation and a less efficient transamidation was observed for cocompounded PA6TI and polylaurolactam (PA12). We attributed this to differences in the hydrogen‐bonding patterns of the two polyamides. This study opened the way for the preparation of novel high‐performance thermoplastic polyamides and composites through simple melt compounding. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44349.     

Annealing effect on crystalline structure and mechanical properties in long glass fiber reinforced polyamide 66

Generally, annealing is one of the important post‐processing methods used to obtain injection molding products coupled with excellent comprehensive performance. Based on a series of experimental studies in this work, a systematic investigation was performed to research the annealing effect on crystalline structure and mechanical properties in long glass fiber reinforced polyamide 66 (LGF‐PA66) composite. The composite was prepared by injection molding, using LGF‐PA66 pellet with 50 wt % fiber content and 12 mm length. Composite samples were annealed in 120 °C to 200 °C range and then subjected to various tests at room temperature. Besides, the releasing strain during a specific temperature cycle was also investigated. Our results suggest that annealing treatment had a neglected impact on the crystallinity and crystal morphology of LGF‐PA66 composite. However, with the increasing of processing temperature, annealing could strikingly promote the phase transition from γ to α and the further growth of α₂ crystal in (010)/(110). In addition, annealing of LGF‐PA66 composite resulted in a drastic increase in tensile and flexural properties and a reduction in impact strength, along with the transition of failure mode. The changes in mechanical properties were attributed to the crystal transition, strengthening of matrix performance, and the release of residual stress. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44832.     

Amelioration of acrylonitrile–butadiene copolymer properties using natural rubber graft p‐aminophenol

A two‐roll mill machine was used for the grafting of p‐aminophenol (pAP) onto natural rubber (NR). The prepared NR graft p‐aminphenol (NR‐g‐pAP) was characterized by ¹H NMR and IR spectroscopy techniques. The goal of this article is to study the effect of commercial antioxidants, N‐phenyl‐N′‐(1,3‐dimethylbutyl)‐p‐phenylenediamine (6PPD) and N‐phenyl‐N′‐isopropyl‐p‐phenylenediamine (IPPD), and the prepared NR‐g‐pAP, on the mechanical properties of acrylonitrile–butadiene (NBR) vulcanizates, the fluid compatibility of NBR vulcanizates, the hydraulic brake and clutch fluid dot, the diffusion out for NBR vulcanizate components, and the compression recovery of NBR vulcanizates. This study indicates that the NBR copolymer vulcanizate which contains the prepared NR‐g‐pAP has good protection against mechanical stress and the diffusion out of NBR vulcanizate components. The 6PPD and the prepared NR‐g‐pAP ameliorates the fluid compatibility of the oil seals, which is based on NBR as elastomer, and the hydraulic brake and clutch fluid dot. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Mechanical properties and nonisothermal crystallization of polyamide 6/carbon fiber composites toughened by maleated elastomers

Polyamide 6/carbon fiber (PA6/CF) composites toughened with maleated elastomers were prepared by melt blending using twin‐screw extruder followed by injection molding. Three kinds of maleated elastomers, maleic anhydride (MAH)‐grafted ethylene‐vinyl acetate copolymer (EVA‐g‐MAH), MAH‐grafted ethylene‐propylene‐diene terpolymer (EPDM‐g‐MAH), and MAH‐grafted hydrogenated styrene‐butadiene‐styrene (SEBS‐g‐MAH), were used to toughen the PA6/CF composites. The mechanical properties, morphology, nonisothermal crystallization, and subsequent melting behavior of PA6 hybrid composites were investigated. Mechanical tests indicated that incorporation of elastomers improved the impact properties of CF‐reinforced PA composites accompanied with loss of tensile strength and modulus. It was observed from scanning electron microscope photographs that modification with maleated elastomers improved the interfacial adhesion between the CFs and PA6 matrix. Nonisothermal crystallization behavior showed that three kinds of elastomers had negative effect on crystallization and retarded crystallization of PA6. Kissinger's analysis illustrated that addition of CF slightly increased the crystallization activation energy of PA6, whereas incorporation of elastomers reversed it compared with pure PA6. Furthermore, a slight decrease in crystallinity and melting peak of the composites after incorporation of elastomers was observed compared with pure PA6. Polarizing optical microscope results showed that the transcrystallinity phenomenon seemed to be also affected when the matrix was added by the elastomers. POLYM. COMPOS., 35:2170–2179, 2014. © 2014 Society of Plastics Engineers     

Preparation and characterization of the ethylene‐vinyl acetate copolymer partially hydrolyzed assisted by microwave radiation

Ethylene‐vinyl acetate copolymer (EVA) was modified by hydrolysis using dielectric heating. The modified EVA was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis (TG), ¹H Nuclear magnetic resonance (NMR), gel permeation chromatography, and small‐angle X‐ray scattering. The results showed that the EVA was hydrolyzed with degree between 36.1 and 42.6% according to ¹H NMR and TG results. The relative reaction rate for the sample prepared in the oil bath was ～9%/h, while in the dielectric was ～150%/h for 15 min. This significant improvement was due to the specific effect of microwave‐assisted reactions through dipole rotation and ionic polarization contributions. The hydrolysis reaction promoted a reduction of the pendent group size of EVA backbone. This change directly contributed to increasing melt temperature, crystallization temperature, melt and crystallization enthalpies. Also, decreased the long period, increased the volume crystallinity, and caused reductions amorphous/crystalline interface and two‐phase model deviations. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44558.     

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     

Structure and dynamic properties of nitrile‐butadiene rubber/hindered phenol composites

Crosslinked nitrile‐butadiene rubber (NBR)/hindered phenol composites were successfully prepared by mixing tetrakis [methylene‐3‐(3‐5‐ditert‐butyl‐4‐hydroxy phenyl) propionyloxy] methane (AO‐60) into NBR with 35% acrylonitrile mass fraction. The structural and mechanical properties of the NBR/AO‐60 composites were systematically investigated by using differential scanning calorimeter, XRD, Fourier transform infrared, scanning electronic microscope, dynamic mechanical analyzer, and tensile testing. The results indicated that the AO‐60 changed from crystalline form into amorphous form, and most of the AO‐60 molecules could be uniformly dispersed in the NBR matrix. The glass transition temperature (T_g) of NBR/AO‐60 composites increased gradually with increasing content of AO‐60. The increase in T_g could be attributed to the formation of a strong hydrogen bonding network between the AO‐60 molecules and the NBR matrix. Unlike the pure NBR, the NBR/AO‐60 rubber composites had only one transition with a high loss factor. With increasing content of AO‐60, the loss peak shifted to the high temperature region, the loss factor increased from 1.45 to 1.91, and the area under the tan δ versus temperature curve (TA) also showed a significant increase. All these results were ascribed to the good compatibility and strong intermolecular interactions between NBR and AO‐60. Furthermore, all NBR/AO‐60 composites exhibited higher glass transition temperatures and tensile strength than NBR, and they had other desirable mechanical properties. They have excellent prospects in damping material applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of the ionic liquid [bmim]PF6 on the nonisothermal crystallization kinetics behavior of poly(ether‐b‐amide)

Blending ionic liquid with crystalline polymer permits the design of new high‐performance composite materials. The final properties of these materials are critically depended on the degree of crystallinity and the nature of crystalline morphology. In this work, nonisothermal crystallization behavior of poly(ether‐b‐amide) (Pebax®1657)/room temperature ionic liquid (1‐butyl‐3‐methylimidazolium hexafluorophosphate, [bmim]PF₆) was investigated by differential scanning calorimetry. The presence of [bmim]PF₆ can retard the nucleation of Pebax®1657 and lead to the crystallization depression of the PA block and the crystalline disappearance of the PEO block. However, the dilution effect of the IL results in a higher growth rate of crystallization of PA block. The influence of [bmim]PF₆ content and cooling rate on crystallization mechanism and spherulitc structures was determined by the Avrami equation modified by Jeziorny and Mo's methods, whereas the Ozawa's approach fails to describe the nonisothermal crystallization behavior of Pebax®1657/[bmim]PF₆ blends. In the modified Avrami analysis, the Avrami exponent of PA blocks, n > 3, for pure Pebax®1657, while 3 > n > 2 for Pebax®1657/[bmim]PF₆ blends testifies the transformation of crystallization growth pattern induced by [bmim]PF₆ from three‐dimensional growth of spherulites to a combination of two‐ and three‐dimensional spherulitic growth. Further, lower activation energy for the nonisothermal crystallization of PA blocks of Pebax®1657 can be observed with the increase of [bmim]PF₆ content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42137.     

Polymer blends of carboxylated butadiene‐acrylonitrile copolymer (nitrile rubber) and polyamide 6 developed in twin screw extrusion

Polymer blends of carboxylated butadiene‐acrylonitrile copolymer (nitrile rubber) and polyamide 6 (PA6) were developed in twin screw extrusion. The rubber was cured with SP 1045 methylol phenolic resin during melt mixing in twin screw. Effect of degree of carboxylation in the rubber phase on blend properties has been assessed. Phase morphologies have been characterized using transmission electron microscopy. A compatibilizing NBR‐g‐Nylon 6 graft copolymer generated in situ during melt mixing via interfacial reaction between the ? COOH groups in NBR and the ? NH₂ end groups in nylon 6 has been effective in generating a fine and stable dispersion of the rubber within the polyamide matrix. The graft copolymer has been characterized by DMTA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 372–377, 2007