4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites: Preparation and properties

4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites were prepared by the sol–gel process of tetrabutyl titanate in the presence of 4,4′‐bismaleimidodiphenyl methane modified novolak resin prepolymers with acetyl acetone as a stabilizer. These nanocomposite materials were characterized by Fourier transform infrared analysis, dynamical mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and field emission scanning electron microscopy. Nanometer titania particles were formed in the novolak resin matrix, and the average original particle size of the dispersed phase in the nanocomposites was less than 150 nm, but particle aggregates of larger size existed. The introduction of the titania inorganic phase with a nanoscale domain size did not improve the glass‐transition temperature of the nanocomposites but lowered the thermal resistance of the material because of the incomplete removal of acetyl acetone coordinated with tetrabutyl titanate, and it improved the modulus of the material at lower temperatures (<200°C) but lowered the modulus at higher temperatures (>250°C). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 52–57, 2006     

Preparation and characterization of epoxy/kaolinite nanocomposites

Epoxy/kaolinite nanocomposites were prepared by adding the organically modified layered kaolinite to an epoxy resin [biphenyl phenol novolac epoxy resin (BPNE)] with 4,4′‐diamino biphenyl sulfone (DDS) as a curing agent. The dispersion state of the kaolinite within crosslinked epoxy‐resin matrix was examined by X‐ray diffraction (XRD) and transmission electron micrograph (TEM). The effects of kaolinite on thermal properties were investigated and discussed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Experimental results show that BPNE/kaolinite nanocomposites exhibit improved thermal than pure BPNE. When the kaolinite content is 5 wt %, the BPNE/kaolinite nanocomposites show the best thermal properties. These results indicate that nanocomposition is an efficient and convenient method to improve the thermal properties of BPNE. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Cloisite clay‐infused phenolic foam nanocomposites

A sonochemical technique was developed to infuse Cloisite clay nanoparticles into phenolic foam materials. Phenolic resin solution (Part A) was mixed with clay particles, and irradiated using a high intensity ultrasonic liquid processor. In the next step, the modified phenolic resin solution containing clay particles was mixed with Part B (containing phenol sulfonic acid, catalyst) through a high‐speed mechanical stirrer. The reaction mixture was then cast into rectangular molds to make nanophased foam panels. Test coupons were cut precisely from the panels to carry out thermal, morphological, and mechanical characterizations. The as‐prepared foam samples were characterized by scanning electron microscopy (SEM), X‐ray diffraction, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The SEM studies have shown that the particles are well dispersed over the entire volume of the matrix with minimal agglomeration. The foam cells structures are well‐ordered and uniform in size and shape. The TGA and DSC analyses show that the nanophased foams are thermally more stable than the corresponding neat system. Quasistatic compression tests have been carried out for both nanophased and neat foams systems. The test results show that there is a significant increase (approximately in the range of 150–180%) in the compressive strength and modulus of the nanophased foams over the neat system. This improvement in compressive properties has been noted repeatedly for multiple batches and with a minimum of three specimens tested from each batch. Details of the synthesis, thermal and mechanical characterization are presented in this paper. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 308‐314, 2007     

Mechanical and morphological properties of organic–inorganic,hybrid, clay‐filled,and cyanate ester/siloxane toughened epoxy nanocomposites

Organic–inorganic hybrids involving cyanate ester and hydroxyl‐terminated polydimethylsiloxane (HTPDMS) modified diglycidyl ether of bisphenol A (DGEBA; epoxy resin) filled with organomodified clay [montmorillonite (MMT)] nanocomposites were prepared via in situ polymerization and compared with unfilled‐clay macrocomposites. The epoxy‐organomodified MMT clay nanocomposites were prepared by the homogeneous dispersion of various percentages (1–5%), and the resulting homogeneous epoxy/clay hybrids were modified with 10% HTPDMS and γ‐aminopropyltriethoxysilane as a coupling agent in the presence of a tin catalyst. The siliconized epoxy/clay prepolymer was further modified separately with 10% of three different types of cyanate esters, namely, 4,4′‐dicyanato‐2,2′‐diphenylpropane, 1,1′‐bis(3‐methyl‐4‐cyanatophenyl) cyclohexane, and 1,3‐dicyanato benzene, and cured with diaminodiphenylmethane as a curing agent. The reactions during the curing process between the epoxy, siloxane, and cyanate were confirmed by Fourier transform infrared analysis. The results of dynamic mechanical analysis showed that the glass‐transition temperatures of the clay‐filled hybrid epoxy systems were lower than that of neat epoxy. The data obtained from mechanical studies implied that there was a significant improvement in the strength and modulus by the nanoscale reinforcement of organomodified MMT clay with the matrix resin. The morphologies of the siloxane‐containing, hybrid epoxy/clay systems showed heterogeneous character due to the partial incompatibility of HTPDMS. The exfoliation of the organoclay was ascertained from X‐ray diffraction patterns. The increase in the percentage of organomodified MMT clay up to 5 wt % led to a significant improvement in the mechanical properties and an insignificant decrease in the glass‐transition temperature versus the unfilled‐clay systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation and characterization of carbon nanofiber reinforced thermoplastic polyurethane nanocomposites

The effect of CNFs on hard and soft segments of TPU matrix was evaluated using Fourier transform infrared (FTIR) spectroscope. The dispersion and distribution of the CNFs in the TPU matrix were investigated through wide angle X‐ray diffraction (WAXD), field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), polarizing optical microscope (POM), and atomic force microscope (AFM). The thermogravimetric analysis (TGA) showed that the inclusion of CNF improved the thermal stability of virgin TPU. The glass transition temperature (T_g), crystallization, and melting behaviors of the TPU matrix in the presence of dispersed CNF were observed by differential scanning calorimetry (DSC). The dynamic viscoelastic behavior of the nanocomposites was studied by dynamical mechanical thermal analysis (DMTA) and substantial improvement in storage modulus (E') was achieved with the addition of CNF to TPU matrix. The rheological behavior of TPU nanocomposites were tested by rubber processing analyzer (RPA) in dynamic frequency sweep and the storage modulus (G') of the nanocomposites was enhanced with increase in CNF loading. The dielectric properties of the nanocomposites exhibited significant improvement with incorporation of CNF. The TPU matrix exhibits remarkable improvement of mechanical properties with addition of CNF. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Dynamic mechanical,thermal, and morphological properties of silane‐treated montmorillonite reinforced polycarbonate nanocomposites

Three different loading of 3‐aminopropyltriethoxysilane (APS) was used to modify the Na‐montmorillonite via cation exchange technique. The Na‐MMT and silane‐treated montmorillonite (STMMT) were melt‐compounded with polycarbonate (PC) by using Haake Minilab machine. The PC nanocomposite samples were prepared by using Haake Minijet injection molding technique. The intercalation and exfoliation of the PC/MMT nanocomposites were characterized by using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The thermal properties of the PC nanocomposites were investigated by using dynamic mechanical analyzer and thermogravimetry analyzer. XRD and TEM results revealed partial intercalation and exfoliation of STMMT in PC matrix. Increase of APS concentration significantly enhanced the storage modulus (E′) and improved the thermal stability of PC nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Epoxy‐silica nanocomposites: Preparation,experimental characterization,and modeling

Silica nanoparticles having different sizes were obtained by the sol‐gel process and characterized. The prepared nanoparticles were subsequently used as reinforcing fillers to prepare epoxy‐based composites with a silica content ranging from 1 to 5 wt %. SEM analysis and tensile tests carried out on the silica‐epoxy nanocomposites indicated the absence of particle aggregation and a reinforcing effect in terms of increased elastic modulus. Mechanical properties were also modeled by using a finite element code able to construct a numerical model from a microstructural image of the material. A more reliable model was prepared by considering the presence of an interphase layer surrounding the particles with intermediate elastic properties between the epoxy and the inclusions and a characteristic size proportional to the particle radius. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2382–2386, 2005     

The characterization of organic modified clay and clay‐filled PMMA nanocomposite

Recently, polymer–clay hybrid materials have received considerable attention from both a fundamental research and application point of view. 1 - 3 This organic–inorganic hybrid, which contains a nanoscale dispersion of the layered silicates, is a material with greatly improved physical and mechanical characteristics. These nanocomposites are synthesized through in situ polymerization or direct intercalation of the organically modified layered silicate (OLS) into the polymer matrix. Thus, understanding the relationship between the molecular structure and the thermal stability (decomposition temperature, rate, and the degradation products) of the OLS is critical. In this study, modern thermal analysis techniques combined with infrared spectroscopy and mass spectrometry (TGA‐FTIR‐MS) were used to obtain information on the thermal stability and degradation products of organic modified clay. Furthermore, the thermal and mechanical properties of clay‐filled PMMA nanocomposites were determined by using TGA and DSC. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1702–1710, 2002     

Synthesis,characterization and properties of clay‐polyacrylate hybrid materials

A new type of hybrid material of clay with poly (butyl acrylate) (PBA) has been prepared successfully using intercalation‐polymerization process. The structure of the composite was investigated by X‐ray diffraction (XRD), Fourier transform infrared (FTIR), Transmission electron microscope (TEM), and Thermogravimetric analysis (TGA). The results show that the hybrid material prepared has a decomposition central temperature of 485.6°C, 83°C higher than that of pure PBA (402.0°C). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 796–801, 2000     

Mechanical and dielectric properties of short‐carbon‐fibers/epoxy‐modified‐organic‐silicone‐resin as heat resistant microwave absorbing coatings

Heat resistant microwave absorbing coatings were prepared by brushing and thereafter heat treatment, using epoxy modified organic silicone resin as binding material, short carbon fibers (C_sf) as absorbers, talcum powder and glass powder as filling materials. The mechanical and dielectric properties of the coatings before and after heat treatment at 600°C for 10 mins were studied. The results showed that the adhesive power after heat treatment enhances remarkably, both the real (ε′) and imaginary (ε″) parts of the permittivity of the coatings increase with increasing C_sf content in the frequency range of 8.2–12.4 GHz. The calculation value of the reflection loss as single layer absorber indicates that epoxy modified organic silicone resin coatings containing short carbon fibers could be a promising radar absorbing material applied at high temperature. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1392‐1398, 2013     

Synthesis,characterization, and thermo mechanical properties of siloxane‐modified epoxy‐based nano composite

In this study, polymer hybrid composites were synthesized by sol‐gel process. 3‐Amino‐propyltrimethoxysilane [APTMS)/γ‐Glycidoxypropyl trimethoxy‐silane (GPTMS); (4, 4′‐Methylene‐dianiline (DDM)] and 1,4‐Bis(trimethoxysilylethyl) benzene (BTB) were added to DGEBA type epoxy resin for anticipated to exhibit excellent thermal stability. Boron trifluoride monoethylamine (BF₃MEA) was used as catalyst. The structure of nanocomposites was characterized by attenuated total reflectance (ATR) and solid‐state ²⁹Si NMR which suggest EP‐APTMS‐BTB/EP‐GPTMS‐BTB possesses T³; T¹–T⁰, and T¹ structures when the BTB content was lower than 10 wt % and higher 20 wt %, respectively. BF₃MEA was proved to be an effective catalyst for the sol‐gel reaction of APTMS, but it could not promote for GPTMS. From TEM microphotographs, EP‐APTMS‐BTB (10 wt %) possesses a dense inorganic structure (particle size around 5–15 nm) compare with the loose inorganic structure of EP‐GPTM‐/BTB (10 wt %). DSC, TGA were use to analyze the thermal properties of the nanocomposites and DMA was used to analyze the dynamic mechanical properties of hybrid composites. The T_gs of all nanocomposites decreased with the increasing BTB content. A system with BTB content lower than 10 wt % showed good dynamic mechanical property and thermal stability (Td₅ increased from 336°C to 371°C, char yield increased from 27.4 to 30.2%). The structure of inorganic network affects the Td₅ and dynamic mechanical properties of composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40984.     

Enhanced properties of innovative laponite‐filled waterborne acrylic resin dispersions

In view of the possible future applications of waterborne automotive coatings, acrylic‐based nanocomposite dispersions were investigated by the simple mixing of aqueous laponite nanoparticle dispersions with acrylic resin dispersions. The mechanical, flow, and leveling properties of waterborne nanocomposite dispersion formulations containing increasing concentrations of silicate and nonvolatile components (nvc) in the acrylic dispersions were investigated. The results obtained were related to the morphological information obtained from transmission electron microscopy and wide‐angle X‐ray scattering measurements in liquid suspension or on the cured films. At low synthetic silicate loading when flow, leveling, and appearance properties were still acceptable for processing and application, a large increase in the modulus of the cured coating films was observed, which was a result of the special morphology of the laponite‐rich regions of the cured film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 687–697, 2007     

Effects of nanoclay on the properties of cardanol‐modified‐resol‐epoxy‐novolac composite material

A nanocomposite based on nanoclay and resol that was modified with cardanol, a natural alkyl phenol, shows improvement for the glass‐fiber‐reinforced epoxy‐composite system. Dispersion of the nanocomposite was investigated by X‐ray, showing good results obtained by the in situ polymerization method. The mechanical properties of the final composites were improved by doping a 6 wt% of nanoclay in cardanol‐modified‐resol (CMR) into the epoxy matrix. The results show that a 15 wt% of CMR in epoxy is a most suitable ratio. Using polyamide as a curing agent instead of other traditional systems, such as anhydrides or amines for epoxy resin, overcame important limitations, further allowing for improved processability. The overall composite performance was enhanced. Additionally, the thermal stability of the system was investigated by thermal gravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3238–3242, 2007     

Thermal,mechanical, and shape‐memory properties of nanorubber‐toughened,epoxy‐based shape‐memory nanocomposites

Epoxy‐based shape‐memory polymers (ESMPs) are a type of the most promising engineering smart polymers. However, their inherent brittleness limits their applications. Existing modification approaches are either based on complicated chemical reactions or done at the cost of the thermal properties of the ESMPs. In this study, a simple approach was used to fabricate ESMPs with the aim of improving their overall properties by introducing crosslinked carboxylic nitrile–butadiene nanorubber (CNBNR) into the ESMP network. The results show that the toughness of the CNBNR–ESMP nanocomposites greatly improved at both room temperature and the glass‐transition temperature (T_g) over that of the pure ESMP. Meanwhile, the increase in the toughness did not negatively affect other macroscopic properties. The CNBNR–ESMP nanocomposites presented improved thermal properties with a T_g in a stable range around 100 °C, enhanced thermal stabilities, and superior shape‐memory performance in terms of the shape‐fixing ratio, shape‐recovery ratio, shape‐recovery time, and repeatability of shape‐memory cycles. The combined property improvements and the simplicity of the manufacturing process demonstrated that the CNBNR–ESMP nanocomposites are desirable candidates for large‐scale applications in the engineering field as smart structural materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45780.     

Preparation and characterization of light‐cured methacrylate/montmorillonite nanocomposites

Polymer/clay nanocomposites were prepared from dimethacrylate monomers, commonly used in dental restorative resins, and an organically modified silicate (montmorillonite). The photopolymerization process was hardly affected by the presence of the silicate filler, and thus 2 mm thick samples containing 3 wt% clay were extensively cured. Transmission electron microscopy revealed that the montmorillonite platelets were either intercalated or exfoliated. Nevertheless, for all formulations, intermediate‐sized aggregates of about 1 µm were present and their fraction increased as the amount of filler increased. The presence of the clay was found to have no major effect on the flexural modulus and compressive yield strength of the nanocomposites. Moreover, the water uptake of nanocomposites containing 3 wt% clay was about 10–15% higher than that of unfilled monomers. Modification of the clay surface with alternative organic cations is certainly necessary in order to achieve an optimal dispersion of the clay in the polymer matrix. Copyright © 2010 Society of Chemical Industry     

Preparation,characterization, and property testing of condensation‐type silicone/montmorillonite nanocomposites

Nanocomposites (NCs) of silicone rubber and organically modified montmorillonite (OMMT) nanoparticles were prepared and characterized. It was shown that OMMT loadings of 2 and 3.5 parts per hundred resin/filler per weight (phr) produced exfoliation or delamination hybrids, whereas at a concentration of 5 phr, the filler seemed to retain its original crystallographic morphology, and the system shifted to an ordinary reinforced elastomer. Fourier transform infrared analysis, differential scanning calorimetry, and thermogravimetric analysis testing were performed for characterization and showed no effect of the nanofiller on the structural parameters of the composites, with the exception of a reduction in the crystallinity. Dynamic mechanical analysis revealed an increase in the glass‐transition temperature (T_g) at OMMT concentrations of 2 and 3.5 phr, whereas at 5 phr, T_g dropped again. Finally, mechanical testing showed an improvement in the tensile strength and stiffness, whereas improved solvent resistance was recorded by swelling experiments in toluene. This experimental study allowed us to explore the range where the OMMT filler produced NCs with silicone elastomers and, furthermore, showed that the incorporation of OMMT into silicone rubber did not introduce any chemical changes but increased the density of crosslinks; this led to a loss of crystallinity, an increase in T_g, and a significant improvement in the tensile properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Processing and characterization of epoxy–anhydride‐based intercalated nanocomposites

A study of the kinetic and thermal characterization of an epoxy resin (DGEBA) polymerized with a methyl tetrahydrophthalic anhydride reinforced with montmorillonite‐layered silicates is presented. The nanoreinforcement used was compatibilized by exchanging the cations between the silicate layers with alkylammonium salts, containing long hydrocarbon chains. The aim of this study was to develop new nanocomposites based on thermoset resins with improved thermal stability, suitable for electronic applications. Differential scanning calorimetry was used here to produce the polymerization kinetics data, while thermogravimetric analysis was used to evaluate the effects of the nanoreinforcements on the thermal stability and to analyze the degradation kinetics. Unexpected strong effects of the nanocomposite on the polymerization kinetics of the epoxy–anhydride system were detected and evaluated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2532–2539, 2003     

Comprehensive high‐performance epoxy nanocomposites co‐reinforced by organo‐montmorillonite and nano‐SiO2

Comprehensive high‐performance epoxy nanocomposites were successfully prepared by co‐incorporating organo‐montmorillonite (o‐MMT) and nano‐SiO₂ into epoxy matrix. Because of the strong interaction between nanoscale particles, the MMT layers were highly exfoliated, and the exfoliated nanoscale MMT monoplatelets took an interlacing arrangement with the nano‐SiO₂ particles in the epoxy matrix, as evidenced by X‐ray diffraction measurement and transmission electron microscopy inspection. Mechanical tests and thermal analyses showed that the resulting epoxy/o‐MMT/nano‐SiO₂ nanocomposites improved substantially over pure epoxy and epoxy/o‐MMT nanocomposites in tensile modulus, tensile strength, flexural modulus, flexural strength, notch impact strength, glass transition temperature, and thermal decomposition temperature. This study suggests that co‐incorporating two properly selected nanoscale particles into polymer is one pathway to success in preparing comprehensive high‐performance polymer nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Structure‐properties relationship in resol/montmorillonite nanocomposites

Polymer/layered silicate nanocomposites were prepared, adding modified, and nonmodified montmorillonites to a resol resin. It was observed that the composites exhibited an intercalated disordered structure by means of X‐ray diffraction (XRD) and transmission electronic microscopy. The crosslinking density of the resol network was greatly influenced by the presence and type of clay that was added to the resin. The composites filled with the modified montmorillonites showed a lower glass transition temperature value as well as a higher degradation peak at ～ 400°C, which is characteristic of the degradation of methylene bridges, indicating a decrease in the crosslinking density of the resol network when modified clays are added. Resol/unmodified montmorillonite composites exhibited different behavior comparing to the other composites and the resol. A higher thermal resistance was observed in the fragmentation zone and a different tan δ response was seen in the DMA analysis. These differences in the behavior of the composites could be because of the interaction between the resol prepolymer and the clay modifiers and as a result of their chemical compatibility. The hardness and elastic modulus of the resol were improved with the addition of clays. However, higher values were obtained for the composite made with the more dispersed montmorillonite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of organo‐phosphorus and nano‐clay materials on the thermal and fire performance of epoxy resins

The results of flame retardance and thermal stability of a reactively modified organo‐phosphorus diglycidylether of bisphenol‐A and an organo‐phosphorus tetraglycidyl diaminodiphenylmethane are reported here. The organo‐phosphorus epoxy resins were synthesized by the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide and diglycidyl ether of bisphenol‐A and tetraglycidyl diaminodiphenylmethane, respectively, and then cured with a mixture of 3,5‐diethyltoluene‐2,4‐diamine and 3,5‐diethyltoluene‐2,6‐diamine. In addition to this, between 5 and 7.5% of organically modified polymeric layered silicate nano‐clay was also added to neat epoxy resin or to the phosphorus‐modified epoxy resin to investigate any synergies, or otherwise, a combination of clay and phosphorus on the flame, degradation, and thermal properties are also reported. The reaction kinetics of phosphorus‐modified and epoxy cure were studied by FTIR, ¹H‐NMR, and DSC. Thermal properties and morphology of the final product were analyzed by thermogravimetric analysis, dynamic mechanical thermal analysis, X‐ray diffraction, and cone calorimetry. Improvement in flame retardance by cone calorimetry was demonstrated by the addition of only 3% phosphorus or 7.5% clay into the epoxy compared with unmodified epoxy resins, whereas no evidence of synergy for a phosphorus and clay combination was found. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1233–1253, 2004