Effect of poly(styrene‐co‐maleic anhydride) imidization on the miscibility and phase‐separation temperatures of poly(styrene‐co‐maleic anhydride)/poly(vinyl methyl ether) and poly(styrene‐co‐maleic anhydride)/ poly(methyl methacrylate) blends

The objective of this work was to study the miscibility and phase‐separation temperatures of poly(styrene‐co‐maleic anhydride) (SMA)/poly(vinyl methyl ether) (PVME) and SMA/poly(methyl methacrylate) (PMMA) blends with differential scanning calorimetry and small‐angle light scattering techniques. We focused on the effect of SMA partial imidization with aniline on the miscibility and phase‐separation temperatures of these blends. The SMA imidization reaction led to a partially imidized styrene N‐phenyl succinimide copolymer (SMI) with a degree of conversion of 49% and a decomposition temperature higher than that of SMA by about 20°C. We observed that both SMI/PVME and SMI/PMMA blends had lower critical solution temperature behavior. The imidization of SMA increased the phase‐separation temperature of the SMA/PVME blend and decreased that of the SMA/PMMA blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Interpolymer‐specific interactions and miscibility in poly(styrene‐co‐acrylic acid)/poly(styrene‐co‐N,N‐dimethylacrylamide) blends

The miscibility or complexation of poly(styrene‐co‐acrylic acid) containing 27 mol % of acrylic acid (SAA‐27) and poly(styrene‐co‐N,N‐dimethylacrylamide) containing 17 or 32 mol % of N,N‐dimethylacrylamide (SAD‐17, SAD‐32) or poly(N,N‐dimethylacrylamide) (PDMA) were investigated by different techniques. The differential scanning calorimetry (DSC) analysis showed that a single glass‐transition temperature was observed for all the mixtures prepared from tetrahydrofuran (THF) or butan‐2‐one. This is an evidence of their miscibility or complexation over the entire composition range. As the content of the basic constituent increases as within SAA‐27/SAD‐32 and SAA‐27/PDMA, higher number of specific interpolymer interactins occurred and led to the formation of interpolymer complexes in butan‐2‐one. The qualitative Fourier transform infrared (FTIR) spectroscopy study carried out for SAA‐27/SAD‐17 blends revealed that hydrogen bonding occurred between the hydroxyl groups of SAA‐27 and the carbonyl amide of SAD‐17. Quantitative analysis carried out in the 160–210°C temperature range for the SAA‐27 copolymer and its blends of different ratios using the Painter–Coleman association model led to the estimation of the equilibrium constants K₂, K_A and the enthalpies of hydrogen bond formation. These blends are miscible even at 180°C as confirmed from the negative values of the total free energy of mixing ΔG_M over the entire blend composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1011–1024, 2007     

The phase behavior and thermal stability of blends of poly(styrene‐co‐methacrylic acid)/poly(styrene‐co‐ 4‐vinylpyridine)

The hydrogen bonding and miscibility behaviors of poly(styrene‐co‐methacrylic acid) (PSMA20) containing 20% of methacrylic acid with copolymers of poly(styrene‐co‐4‐vinylpyridine) (PS4VP) containing 5, 15, 30, 40, and 50%, respectively, of 4‐vinylpyridine were investigated by differential scanning calorimetry, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). It was shown that all the blends have a single glass transition over the entire composition range. The obtained T_gs of PSMA20/PS4VP blends containing an excess amount of PS4VP, above 15% of 4VP in the copolymer, were found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are able to form interpolymer complexes. The FTIR study reveals presence of intermolecular hydrogen‐bonding interaction between vinylpyridine nitrogen atom and the hydroxyl of MMA group and intensifies when the amount of 4VP is increased in PS4VP copolymers. A new band characterizing these interactions at 1724 cm⁻¹ was observed. In addition, the quantitative FTIR study carried out for PSMA20/PS4VP blends was also performed for the methacrylic acid and 4‐vinylpyridine functional groups. The TGA study confirmed that the thermal stability of these blends was clearly improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Investigation of the structural,thermal, mechanical,and optical properties of poly(methyl methacrylate) and poly(vinylidene fluoride) blends

In this investigation, poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride) (PVDF) blends (w/w) were prepared in a Brabender (South Hackensack, NJ) plasticorder with a thermoplastic mixing chamber (type W60) preheated at 180°C. These blends were further converted into films by a conventional solution casting method and characterized with Fourier transform infrared spectroscopy, differential scanning calorimetry, X‐ray diffraction, mechanical property measurements, impact strength testing, ultraviolet–visible spectroscopy, refractive‐index measurements, and contact‐angle study. The Fourier transform infrared results indicated that the compatibility between these two systems resulted from hydrogen bonding between the carbonyl group of PMMA and the CH₂ group of PVDF. The thermal analysis showed depressions in the glass‐transition temperature, melting temperature, and crystallization temperature. The heat of crystallization increased with an increase in the PVDF content in the blend. An increase in the heat of crystallization meant an increase in the crystallinity. An increase in the cooling rate increased the crystallization rate. The improvement in the mechanical properties of the blend films indicated that the observed behavior was ascribable to a more coherent structure of the blends due to strong specific interactions between PMMA and PVDF chains. The impact strength analysis revealed a substantial increase in the impact strength from 21.64 to 38.52 J/m. Optical absorption spectra suggested the presence of an optical band gap energy that increased with an increase in the PVDF content in the blend. The contact angle against water increased with the PVDF content in the blend film, and this was caused by the hydrophobicity of PVDF due to the CF₂ group of PVDF. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Phase behavior of binary and ternary blends of poly(styrene‐co‐methacrylic acid), poly(styrene‐co‐4‐vinylpyridine), and poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(styrene‐co‐methacrylic acid) (PSMA) and poly(styrene‐co‐4‐vinylpyridine) (PS4VP) of different compositions were prepared and characterized. The phase behavior of these copolymers as binary PSMA/PS4VP mixtures or with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as PPO/PSMA or PPO/PS4VP and PPO/PSMA/PS4VP ternary blends was investigated by differential scanning calorimetry (DSC). This study showed that PPO was miscible with PS4VP containing up to 15 mol % 4‐vinylpyridine (4VP) but immiscible with PS4VP‐30 (where the number following the hyphen refers to the percentage 4VP in the polymer) and PSMA‐20 (where the number following the hyphen refers to the percentage methacrylic acid in the polymer) over the entire composition range. To examine the morphology of the immiscible blends, scanning electron microscopy was used. Because of the hydrogen‐bonding specific interactions that occurred between the carboxylic groups of PSMA and the pyridine groups of PS4VP, chloroform solutions of PSMA‐20 and PS4VP‐15 formed interpolymer complexes. The obtained glass‐transition temperatures (T_g's) of the PSMA‐20/PS4VP‐15 complexes were found to be higher than those calculated from the additivity rule. Although, depending on the content of 4VP, the shape of the T_g of the PPO/PS4VP blends changed from concave to S‐shaped in the case of the miscible blends, two T_g were observed with each PPO/PS4VP‐30 and PPO/PS4VP‐40 blend. The thermal stability of the PSMA‐20/PS4VP‐15 interpolymer complexes was studied by thermogravimetry. On the basis of the obtained results, the phase behavior of the ternary PPO/PSMA‐20/PS4VP‐15 blends was investigated by DSC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Viscoelasticity and morphology of poly(ethylene‐co‐vinyl acetate)/polyisobutylene blends

Blends of an ethylene/vinyl acetate copolymer (EVA) and polyisobutylene of various compositions were prepared by mechanical mixing at a temperature above the melting point of EVA (T_m^EVA) but below the upper critical solution temperature of 170°C for given blends. The rheological properties of the components and blends were studied in the region of small‐amplitude oscillating deformation at temperatures above and below T_m^EVA in the frequency range of 0.01–100 rad/s. At temperatures lower than T_m^EVA, the rheological properties were determined by the existence of the yield stress. With diminishing frequency, the viscosity increased, and the plateau in the relaxation spectrum at low frequencies broadened. The morphology of the blends depended on the conditions of sample heating. The introduction of a finely dispersed filler into the blends led to an anomalous drop in the viscosity. The morphology of the systems that arose by mechanical blending of the molten components was the important factor in the rheological behavior. The observed effects were examined in the framework of the concept of structural networks formed in melts by nonmelted crystallites of EVA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2700–2707, 2006     

Crystallization and melting behavior of partially miscible six‐armed poly(l‐lactic acid)/poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) blends

The crystallization kinetics and spherulitic morphology of six‐armed poly(L‐lactic acid) (6a‐PLLA)/poly(3‐hydroxybutyrate‐co?3‐hydroxyvalerate) (PHBV) crystalline/crystalline partially miscible blends were investigated with differential scanning calorimetry and polarized optical microscopy in this study. Avrami analysis was used to describe the isothermal crystallization process of the neat polymers and their blends. The results suggest that blending had a complex influence on the crystallization rate of the two components during the isothermal crystallization process. Also, the crystallization mechanism of these blends was different from that of the neat polymers. The melting behavior of these blends was also studied after crystallization at various crystallization temperatures. The crystallization of PHBV at 125°C was difficult, so no melting peaks were found. However, it was interesting to find a weak melting peak, which arose from the PHBV component for the 20/80 6a‐PLLA/PHBV blend after crystallization at 125°C, and it is discussed in detail. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42548.     

Isothermal and non‐isothermal crystallization of poly(L‐lactic acid)/poly(butylene terephthalate) blends

Isothermal and non‐isothermal crystallization kinetics of poly(l ‐lactic acid)/poly(butylene terephthalate) (PLLA/PBT) blends containing PLLA as major component is detailed in this contribution. PLLA and PBT are not miscible, but compatibility of the polymer pair is ensured by interactions between the functional groups of the two polyesters, established upon melt mixing. Crystal polymorphism of the two polyesters is not influenced by blending, as probed by wide‐angle X‐ray analysis. The addition of PLLA does not affect the temperature range of crystallization kinetics of PBT, nor the crystallinity level attained when the blends are cooled from the melt at constant rate. Conversely, PBT favors crystallization of the biodegradable polyester. The addition of PBT results in an anticipated onset of crystallization of PLLA during cooling at a fixed rate, with a sizeable enhancement of the crystal fraction. Isothermal crystallization analysis confirmed the faster crystallization rate of PLLA in the presence of PBT. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40372.     

Degradation behaviors of linear low‐density polyethylene and poly(L‐lactic acid) blends

In this study, the degradability of linear low‐density polyethylene (LLDPE) and poly(L ‐lactic acid) (PLLA) blend films under controlled composting conditions was investigated according to modified ASTM D 5338 (2003). Differential scanning calorimetry, X‐ray diffraction, and Fourier transform infrared spectroscopy were used to determine the thermal and morphological properties of the plastic films. LLDPE 80 (80 wt % LLDPE and 20 wt % PLLA) degraded faster than grafted low‐density polyethylene–maleic anhydride (M‐g‐L) 80/4 (80 wt % LLDPE, 20 wt % PLLA, and 4 phr compatibilizer) and pure LLDPE (LLDPE 100). The mechanical properties and weight changes were determined after composting. The tensile strength of LLDPE 100, LLDPE 80, and M‐g‐L 80/4 decreased by 20, 54, and 35%, respectively. The films, as a result of degradation, exhibited a decrease in their mass. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Kraft lignin/poly(ethylene oxide) blends: Effect of lignin structure on miscibility and hydrogen bonding

Blends of poly(ethylene oxide) (PEO) with softwood kraft lignin (SKL) were prepared by thermal blending. The miscibility behavior and hydrogen bonding of the blends were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The experimental results indicate that PEO was miscible with SKL, as shown by the existence of a single glass‐transition temperature over the entire composition range by DSC. In addition, a negative polymer–polymer interaction energy density was calculated on the basis of the melting point depression of PEO. The formation of strong intermolecular hydrogen bonding was detected by FTIR analysis. A comparison of the results obtained for the SKL/PEO blend system with those previously observed for a hardwood kraft lignin/PEO system revealed the existence of stronger hydrogen bonding within the SKL/PEO blends but weaker overall intermolecular interactions between components; this suggested that more than just hydrogen bonding was involved in the determination of the blend behavior in the kraft lignin/PEO blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1437–1444, 2005     

Miscibility and transesterification in ternary blends of poly(ethylene naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide)

Miscibility and morphology of poly(ethylene 2,6‐naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide) (PEN/PPT/PEI) blends were studied by differential scanning calorimetry (DSC), optical microscopy (OM), proton nuclear magnetic resonance imaging (¹H‐NMR), and wide‐angle X‐ray diffraction (WAXD). OM and DSC results from ternary blends revealed the immiscibility of PEN/PPT/PEI blends, but ternary blends of all compositions were phase‐homogeneous following heat treatment at 300°C for over 60 min. Annealing samples at 300°C yielded an amorphous blend with a clear and single T_g at the final state. Experimental data from ¹H‐NMR revealed that PEN/PPT copolymers (ENPT) were formed by the so‐called transesterification. The effect of transesterification on glass transition and crystallization was discussed in detail. The sequence structures of the copolyester were identified by triad analysis, which showed that the mean sequence lengths became shorter and the randomness increased with heating time. The results reveal that a random copolymer improved the miscibility of the ternary blends, in which, the length of the homo segments in the polymer chain decreased and the crystal formation was disturbed because of the irregularity of the structure, as the exchange reaction proceeded. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3840–3849, 2006     

Specific interactions in poly(styrene‐co‐2‐hydroxyethyl acrylate)/poly(styrene‐co‐N,N‐dimethylacrylamide) systems

Amphiphilic copolymers of poly(styrene‐co‐2‐hydroxyethyl acrylate) (SHEA) and poly(styrene‐co‐N, N‐dimethylacrylamide) (SAD) of different compositions were prepared by free radical copolymerization and characterized by different techniques. Depending on the nature of the solvent and the densities of interacting species incorporated within the polystyrene matrices, novel materials as blends or interpolymer complexes with properties different from those of their constituents were elaborated when these copolymers are mixed together. The specific interpolymer interactions of hydrogen bonding type and the phase behavior of the elaborated materials were investigated by differential scanning calorimetry (DSC) and Fourier transform infra red spectroscopy (FTIR). The specific interactions of hydrogen bonding type that occurred within the SHEA and within their blends with the SAD were evidenced by FTIR qualitatively by the appearance of a new band at 1626 cm^?1 and quantitatively using appropriate spectral curve fitting in the carbonyl and amide regions. The variation of the glass transition temperature with the blend composition behaved differently with the densities of interacting species. The thermal degradation behavior of the materials was studied by thermogravimetry. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Morphology and thermal behavior of organo‐bentonite clay/poly(styrene‐co‐methacrylic acid)/poly(isobutyl methacrylate‐co‐4‐vinylpyridine) nanocomposites

Poly(styrene‐co‐methacrylic acid) containing 29 mol % of methacrylic acid (SMA‐29) and poly(isobutyl methacrylate‐co‐4‐vinylpyridine) containing 20 mol % of 4‐vinylpyridine (IBM4VP‐20) were synthesized, characterized, and used to elaborate binary and ternary nanocomposites of different ratios with a 3% by weight hexadecylammonium‐modified bentonite from Maghnia (Algeria) by casting method from tetrahydrofuran (THF) solutions. The morphology and the thermal behavior of these binary and ternary elaborated nanocomposites were investigated by X‐ray diffraction, scanning electron microscopy, FTIR spectroscopy, differential scanning calorimetry, and thermogravimetry. Polymer nanocomposites and nanoblends of different morphologies were obtained. The effect of the organoclay and its dispersion within the blend matrix on the phase behavior of the miscible SMA29/IBM4VP20 blends is discussed. The obtained results showed that increasing the amount of SMA29 in the IBM4VP20/SMA29 blend leads to near exfoliated nanostructure with significantly improved thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Miscibility study of poly(vinyl chloride)/poly(methyl methacrylate‐co‐4‐vinylpyridine) by viscosimetry,DSC, and FTIR

The miscibility of the poly(vinyl chloride)/poly(methylmethacrylate) system were improved by introducing pyridine units into poly(methylmethacrylate) main. For this purpose, we have synthesized through a radical polymerization a series of methylmethacrylate‐co‐vinyl‐4‐pyridine copolymers of different compositions and carried out a comparative study by viscosimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopic (FTIR) methods. The viscosimetric analysis using the Krigbaum‐Wall, K. K. Chee, and Compos approaches revealed that, the Poly(vinyl chloride)/poly(methylmethactylate‐co‐4‐vinylpyridine)(PVC/MMA4VP‐15) at 15 wt % of 4‐vinylpyridine systems in tetrahydrofuran are completely miscible in all proportions. The differential scanning calorimetry analysis confirmed the miscibility of these systems in all proportions by the appearance of only one glass transition temperature between those of the two pure constituents. The Kwei and Schneider approaches showed also the miscibility of this system, which is due to the specific interactions between the acidic hydrogen atom of PVC and the nitrogen of MMA4VP‐15. The use of FTIR method has confirmed the occurrence of this kind of interactions by broadening and shifting of the involved functional groups vibration bands. In this work, we have also carried out a preliminary test of sorption of THF aqueous solution by PVC and PVC/MMA4VP‐15 blend membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Compatibility of low‐density polyethylene/poly(ethylene‐co‐vinyl acetate) binary blends prepared by melt mixing

The compatibility of low‐density polyethylene and poly(ethylene‐co‐vinyl acetate) containing 18 wt % vinyl acetate units (EVA‐18) was studied. For this purpose, a series of different blends containing 25, 50, or 75 wt % EVA‐18 were prepared by melt mixing with a single‐screw extruder. For each composition, three different sets of blends were prepared, which corresponded to the three different temperatures used in the metering section and the die of the extruder (140, 160, and 180°C), at a screw rotation speed of 42 rpm. Blends that contained 25 wt % EVA‐18 were also prepared through mixing at 140, 160, or 180°C but at a screw speed of 69 rpm. A study of the blends by differential scanning calorimetry showed that all the prepared blends were heterogeneous, except that containing 75 wt % EVA‐18 and prepared at 180°C. However, because of the high interfacial adhesion, a fine dispersion of the minor component in the polymer matrix was observed for all the studied blends with scanning electron microscopy. The tensile strengths and elongations at break of the blends lay between the corresponding values of the two polymers. The absence of any minimum in the mechanical properties was strong evidence that the two polymers were compatible over the whole range of composition. The thermal shrinkage of the blends at various temperatures depended mainly on the temperature and EVA‐18 content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 841–852, 2003     

Poly(2‐alkyloyloxyethylacrylate) and poly(2‐alkyloyloxyethylacrylate‐co‐methylacrylate) comblike polymers as novel phase‐change materials for thermal energy storage

A series of poly(2‐alkyloyloxyethylacrylate) and poly(2‐alkyloyloxyethylacrylate‐co‐methylacrylate) polymers as novel polymeric phase‐change materials (PCMs) were synthesized starting from 2‐hydroxyethylacrylate and fatty acids. The chemical structure and crystalline morphology of the synthesized copolymers were characterized with Fourier transform infrared and ¹H‐NMR spectroscopy and polarized optical microscopy, respectively, and their thermal energy storage properties and thermal stability were investigated with differential scanning calorimetry and thermogravimetric analysis, respectively. The thermal conductivities of the PCMs were also measured with a thermal property analyzer. Moreover, thermal cycling testing showed that the copolymers had good thermal reliability and chemical stability after they were subjected to 1000 heating/cooling cycles. The synthesized poly(2‐alkyloyloxyethylacrylate) polymers and poly(2‐alkyloyloxyethylacrylate‐co‐methylacrylate) copolymers as novel PCMs have considerable potential for thermal energy storage and temperature‐control applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal and spectroscopic characterization of microbial poly(3‐hydroxybutyrate) submicrometer fibers prepared by electrospinning

Submicrometer fibers based on the microbially synthesized ultra‐high‐molecular‐weight poly(3‐hydroxybutyrate) (PHB) were generated by an electrospinning (ES) process with chloroform as the solvent. To characterize the resulting electrospun fibers in comparison with the pure PHB before ES, differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy were performed. The diameters of the electrospun fibers characterized by SEM were in the range 400–1000 nm. Thermal analysis showed that the electrospun fibers contained both helical (α form) and trans‐zigzag (β form) crystals, whereas the solution‐cast PHB films mostly possessed the common helical structure. In addition, the crystallinity of the electrospun PHB fibers increased compared to that of the solution‐cast PHB films. Conformational changes occurred with the high extensional flow in the ES jets. Furthermore, the results from polarized FTIR measurements demonstrate that PHB molecules were oriented parallel to the fiber axis. As a result, the electrospun fibers exhibited strong birefringence under the polarized light. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1860–1867, 2007     

Poly(L‐lactide)/polypropylene blends: Evaluation of mechanical,thermal, and morphological characteristics

Poly(L lactide) (PLA) was blended with polypropylene (PP) at various ratios (PLA:PP = 90 : 10, 80 : 20, 70 : 30, and 50 : 50) with a melt‐blending technique in an attempt to improve the melt processability of PLA. Maleic anhydride (MAH)‐grafted PP and glycidyl methacrylate were used as the reactive compatibilizers to induce miscibility in the blend. The PLA/PP blend at a blend ratio of 90 : 10, exhibited optimum mechanical performance. Differential scanning calorimetry and thermogravimetric analysis studies showed that the PLA/PP/MAH‐g‐PP blend had the maximum thermal stability with the support of the heat deflection temperature values. Furthermore, dynamic mechanical analysis findings revealed an increase in the glass‐transition temperature and storage modulus with the addition of MAH‐g‐PP compatibilizer. The interaction between the compatibilizers and constituent polymers was confirmed from Fourier transform infrared spectra, and scanning electron microscopy of impact‐fractured samples showed that the soft PP phase was dispersed within the PLA matrix, and a decrease in the domain size of the dispersed phase was observed with the incorporation of MAH‐g‐PP, which acted as a compatibilizer to improve the compatibility between PLA and PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Sequential interpenetrating polymer networks of novolac resin and poly(n‐butyl methacrylate)

Novolac resin/poly(n‐butyl methacrylate), P(n‐BMA), sequential interpenetrating polymer networks (both semi and full types) were prepared and characterization of the various compositions (up to 40% by weight of PF incorporation) was performed in terms of mechanicals, namely, ultimate tensile strength (UTS), percentage elongation at break (% E.B.), modulus, and toughness. Thermal properties were studied by differential scanning calorimetry and thermogravimetric analysis (TGA). Crosslink densities of the IPNs were calculated using Flory‐Rehner equation. The morphological features were studied through scanning electron microscope. There was a gradual decrease of modulus and UTS with consequent increases in % E. B. and toughness with increasing proportions of P(n‐BMA). An inward shifting and lowering of the glass transition temperatures of the IPNs (compared with that of pure phenolic resin) with increasing proportions of P(n‐BMA) were observed. The TGA thermograms exhibit two‐step degradation patterns. A typical cocontinuous bi‐phasic morphology is evident in the micrographs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4030–4039, 2006     

Fabrication,characterization, and properties of poly(ethylene‐co‐vinyl acetate)/magnetite nanocomposites

Poly(ethylene‐co‐vinyl acetate) (EVA)/magnetite (Fe₃O₄) nanocomposite was prepared with different loading of Fe₃O₄ nanoparticles. The mixing and compounding were carried out on a two‐roll mixing mill and the sheets were prepared in a compression‐molding machine. The effect of loading of nanoparticles in EVA was investigated thoroughly by different characterization technique such as transmission electron microscopy (TEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and technological properties. TEM analysis showed the uniform dispersion of filler in the polymer matrix and the dispersion of filler decreased with increase in filler content. XRD of the nanocomposite revealed the more ordered structure of the polymer chain. An appreciable increase in glass transition temperature was observed owing to the restricted mobility of Fe₃O₄‐filled EVA nanocomposite. TGA and flame resistance studies indicated that the composites attain better thermal and flame resistance than EVA owing to the interaction of filler and polymer segments. Mechanical properties such as tensile strength, tear resistance, and modulus were increased for composites up to 7 phr of filler, which is presumably owing to aggregation of Fe₃O₄ nanoparticle at higher loading. The presence of Fe₃O₄ nanoparticles in the polymer matrix reduced the elongation at break and impact strength while improved hardness of the composite than unfilled EVA. The change in technological properties had been correlated with the variation of polymer–filler interaction estimated from the swelling behavior. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40116.