Temperature sensitive semi‐IPN microspheres from sodium alginate and N‐isopropylacrylamide for controlled release of 5‐fluorouracil

Semi‐interpenetrating network (IPN) of sodium alginate (NaAlg) and N‐isopropylacrylamide (NIPAAm) microspheres were prepared by water‐in‐oil (w/o) emulsification method. The microspheres were encapsulated with 5‐fluorouracil (5‐FU) and release patterns carried in 7.4 pH at temperatures of 25 and 37°C. The semi‐IPN microspheres were characterized by Fourier transform infrared spectroscopy (FTIR). Differential scanning calorimetry (DSC) and scanning electron microscopic studies were done on the drug‐loaded microspheres to confirm the polymorphism of 5‐FU and surface morphology of microspheres. These results indicated the molecular level dispersion of 5‐FU in the semi‐IPN microspheres. Particle size and size distribution were studied by laser light diffraction technique. Microspheres exhibited release of 5‐FU up to 12 h. The swelling studies were carried in 1.2 and 7.4 pH buffer media at 25 and 37°C. Drug release from NaAlg‐NIPAAm semi‐IPN microspheres at 25 and 37°C confirmed the thermosensitive nature by in vitro dissolution. The micro domains have released in a controlled manner due the presence of NIPAAm in the matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Novel methyl cellulose‐grafted‐acrylamide/gelatin microspheres for controlled release of nifedipine

Naturally available carbohydrate polymers such as methylcellulose (MC) and gelatin (Ge) have been widely studied in the previous literature for controlled release (CR) applications. In this study, methyl cellulose‐g‐acrylamide/gelatin (MC‐g‐AAm/Ge) microspheres were prepared by water‐in‐oil (W/O) emulsion method and crosslinked with glutaraldehyde to encapsulate with nifedipine (NFD), an antihypertensive drug. The microspheres prepared were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and laser particle size analyzer. DSC thermograms of NFD‐loaded AAm‐MC/Gel microspheres confirmed the molecular level distribution of NFD in the matrix. SEM indicated the formation of spherical particles. Swelling experiments supported the drug diffusion characteristics and release data of the matrices. Cumulative release data were analyzed using an empirical equation to understand the nature of transport of drug through the matrices. Controlled release characteristics of the matrices for NFD were investigated in pH 7.4 media. Drug was released in a controlled manner up to 12 h. Particle size and size distribution of the microspheres as studied by laser light diffraction particle size analyzer indicated their sizes to be around 120 μm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novel thermo‐responsive semi‐interpenetrating network microspheres of gellan gum‐poly(N‐isopropylacrylamide) for controlled release of atenolol

Thermoresponsive microspheres of gellan gum‐poly(N‐isopropylacrylamide), i.e., GG‐P(NIPAAm) semi‐interpenetrating polymer networks (semi‐IPNs) have been prepared by ionic crosslinking and used to study the controlled release (CR) of atenolol (ATL), an antihypertensive drug. Interaction of the drug with polymers was studied by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) was used to confirm the polymorphism and molecular level dispersion of ATL. Scanning electron microscopy (SEM) indicated spherical nature and smooth surfaces of the microspheres with some debris attached on their surfaces. Mean particle size measured by laser light diffraction ranged between 34 and 76 μm. Equilibrium swelling performed at 25°C and 37°C in pH 7.4 phosphate buffer exhibited thermoresponsive nature of the polymers. In vitro drug release performed at 25°C and 37°C indicated temperature‐dependency of ATL release, which was extended up to 12 h. In vitro release profiles at both the temperatures confirmed thermoresponsive nature of the polymers giving pulsatile trends. The % cumulative release data have been fitted to an empirical equation to estimate transport parameters and to understand the nature of drug release. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

pH sensitive interpenetrating network microgels of sodium alginate‐acrylic acid for the controlled release of ibuprofen

pH‐Sensitive interpenetrating network (IPN) microgels (MGs) of sodium alginate (NaAlg) and acrylic acid have been prepared by using water‐in‐oil (W/O) emulsion technique. The MGs were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X‐ray diffractometer (X‐RD). The release of ibuprofen (IB), an anti‐inflammatory drug, from these MGs was studied in pH 1.2 and 7.4 media. MG network consists of NaAlg, which disintegrates in the intestinal fluid, while poly(acrylic acid) provides pH‐sensitivity to the microgel network. The system developed in this study showed a pH‐sensitivity for the release of IB, which was attributed to the diffusion controlled release of the drug through the surfaces of MGs that undergo disintegration after swelling, depending upon the chemical composition of MGs and pH of the medium. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Preparation of Nano‐Sized Copper β‐Resorcylate (β‐Cu) and its Excellent Catalytic Activity for the Thermal Decomposition of Ammonium Perchlorate

Copper β‐resorcylate (cupric 2,4‐dihydroxy‐benzoate, β‐Cu) nanoparticles were prepared at a large‐scale via a facile wet mechanical grinding method and vacuum freeze‐drying process. The as‐prepared β‐Cu nanoparticles were characterized by powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier‐transform infrared spectroscopy (FT‐IR). The results revealed that the nano‐sized β‐Cu is of semi‐spherical shape and of homogeneous distribution, with a fairly uniform size of 100 nm. The formation mechanism of β‐Cu nanoparticles in the whole process was discussed in detail. Furthermore, the catalytic properties of as‐obtained β‐Cu were investigated. The TG/DSC study showed that nano‐sized β‐Cu could be a promising additive for accelerating the thermal decomposition of ammonium perchlorate (AP).     

Preparation and in vitro characterization of poly(sebacic acid‐co‐ricinoleic acid)‐based tamoxifen citrate‐loaded microparticles for breast cancer

This study was aimed to develop an injectable polymeric drug delivery system for tamoxifen citrate (TC) using poly(sebacic acid‐co‐ricinoleic acid) [poly(SA‐RA) 70 : 30 w/w] as a drug carrier for the treatment of estrogen receptor positive breast cancer. Injectable biodegradable microparticles of TC were produced by solvent displacement technique of microencapsulation and were characterized by surface morphology (scanning electron microscopy), particle size, size distribution, physical and chemical interaction (Fourier transform infrared), nature and physical state of drug [DSC and X‐ray diffraction (XRD)], and in vitro release studies. TC loading over different concentrations was analyzed by high performance liquid chromatography (HPLC) technique. Polyanhydride microparticles obtained after lyophilization were nearly spherical in shape with smooth surface and size less than 2.5 μm. TC was dispersed in the form of amorphous state, and TC remains intact and stable during the process of microencapsulation. In vitro drug release studies demonstrated prolonged controlled release of TC with zero‐order kinetics. Stability studies revealed that the production process of microparticles itself did not affect the chemical stability of the drug and polymer forming the particle matrix. Significant difference in drug release capacity was observed in microparticles with different drug loadings, and the drug release was more sustained in microparticles prepared with high TC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Studies on novel semi‐2‐IPNs from polyetherimide and citraconimide

A series of novel semi‐2‐interpenetrating polymeric networks (semi‐2‐IPNs) were prepared through blending in solution using two different polyimides, biscitraconamic acid as a precursor of biscitraconimide (MBMI) with various proportions of polyetherimide (PEI) to achieve optimum properties. Biscitraconamic acid was prepared by reacting citraconic anhydride (CA), 3,3',4,4'‐benzophenone tetracarboxylic dianhydride (BTDA) and bis(3‐aminopropyl)phenyl phosphine (BAPPP) and it was characterized by differential scanning calorimetry (DSC), FTIR, and ¹H‐NMR spectroscopy. Both biscitraconamic acid and PEI were blended in N,N‐dimethylacetamide (DMAc) solution, casted and thermally cured up to 300°C to give semi‐2‐IPNs. The MBMI/PEI semi‐IPN systems were characterized by UV‐Vis spectroscopy, FTIR spectroscopy and thermal techniques. The phase morphology, isothermal aging, and water uptake of semi‐IPN systems have also been studied. The morphological studies on phase distribution were investigated by scanning electron microscopy (SEM). Thermal performance of MBMI/PEI semi‐IPN systems were evaluated by DSC and thermo gravimetric analysis (TGA). All the compositions of semi‐IPN polyimide system were stable up to 400°C and their thermal stability increased with increase in the content of PEI. Isothermal aging studies done at 300°C for various time periods showed good thermo‐oxidative stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of modified bismaleimide/polysulfone semi‐interpenetrating polymer networks

The present work reports a new method of preparing semi‐interpenetrating polymer network (semi‐IPN) membranes through in situ polymerization of bismaleimide (BMI) within polysulfone (PSF). It was found that BMI could be polymerized at ambient conditions in the presence of a proton donor and PSF without the use of an initiator or a catalyst. Chemical structure characterization of these semi‐IPNs by Fourier transform infrared attenuated total reflection (FTIR‐ATR) revealed the possibility of imide cleavage and formation of amic acid when BMI polymerization was continued for a longer time while X‐ray photoelectron spectroscopy (XPS) revealed the protonation of imide nitrogen at shorter polymerization time. It was also found that size of thermoset BMI phase within the PSF thermoplastic has a significant impact on glass‐transition temperature of resulting semi‐IPN. By controlling the thermoset/thermoplastic phase separation of semi‐IPNs through dope composition and formation techniques, gas separation membranes with comparable selectivity and permeance that were up to 12 times higher than corresponding PSF membranes were formed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 369–379, 2006     

Development of transdermal drug‐delivery films with castor‐oil‐based polyurethanes

Two different types of polyurethanes (PUs) were prepared with castor oil, ethylene glycol, isophorene diisocyanate and castor oil, and isophoren diisocyanate and poly‐(ethylene glycol) (400 or 600). PU films were prepared and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and gel permeation chromatography. We prepared transdermal patches by loading different amounts of drug, plasticizer, and penetration enhancer. In vitro drug permeability through the castor‐oil‐based aliphatic PU patches was examined with a Keshary–Chien diffusion cell. The effect of castor oil on the film‐forming properties and the effect of penetration enhancers on diffusion characteristics of indomethacin (IDM) drug through the castor‐oil‐based PU were investigated. Prolonged release of IDM was observed from the prepared PU patches. In vitro drug diffusion revealed that slow and prolonged release of IDM was achieved in the absence of penetration enhancers. The use of penetration enhancers showed a significant effect on drug diffusion. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 779–788, 2007     

Preparation and characterization of a semi‐interpenetrating network gel polymer electrolyte

Poly(PEG200 maleate) was synthesized as a new type crosslinkable prepolymer and the semi‐interpenetrating polymer network (semi‐IPN) gel electrolytes were prepared by means of thermal polymerization. Their intrinsic properties were characterized by FTIR spectroscopy, differential scanning calorimetry (DSC), X‐ray diffractions (XRD), scanning electron microscopy, alternating current impedance (AC impedance), and linear sweep voltammetry. The prepared polymer hosts are transparent and have good mechanical properties. The results of DSC and XRD confirm that the prepared hosts are in amorphous state and they can hold enough liquid electrolytes, which is favorable for Li⁺ ions to transport via both the absorbed liquid electrolyte and the gel of the entire systems. The semi‐IPN gel electrolytes exhibit high ionic conductivity on the order of 10^?3 S cm^?1. Their electrochemical stability up to +4.6 V against Li⁺/Li also makes them potential candidates for application as polymer electrolytes in devices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Preparation and in vitro release behavior of urapidil hydrochloride loading into microspheres based on poly(L‐lactide)

Microencapsulation of the antihypertensive drug urapidil hydrochloride was investigated as a means of controlling drug release and minimizing or eliminating local side effects. Poly(L ‐lactide) (PLLA) microspheres were prepared using an alternative oil‐in‐water (O/W) solvent‐evaporation method such as the O/W cosolvent solvent‐evaporation method and O/W with various electrolytes added to the aqueous phase method. The surface morphology and the size of the microspheres were observed by scanning electron microscope. Meanwhile, the drug loading efficiency of microspheres and the in vitro release of urapidil hydrochloride from microspheres were performed. The release study indicated that the urapidil hydrochloride‐PLLA microspheres exhibited better sustained release capacity, and the kinetics of urapidil hydrochloride‐PLLA microspheres in vitro release could be described by the Higuchi equation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Chitosan and chitosan/β‐cyclodextrin microspheres as sustained‐release drug carriers

The main aim of this study was to compare two microspheres, chitosan (CTS) and CTS/β‐cyclodextrin (β‐CD), made by spray‐drying, as pulmonary sustained drug‐delivery carriers. Theophylline (TH) was used as a model drug. The characteristics of the microspheres and in vitro release were studied. The yield of CTS/β‐CD microspheres was 46.1%, which was higher than that of the CTS microspheres (36.5%). The drug loads of the CTS and CTS/β‐CD microspheres were 22.7 and 21.1%, respectively, whereas the encapsulation efficiencies were 90.7 and 91.4%, respectively. The distribution of 50% [(diameter) d (0.5)] of the CTS microspheres was below 6.49 μm and that of the CTS/β‐CD microspheres was below 4.90 μm. Scanning electron microscopy showed that both microspheres yielded a spherical shape with smooth or wrinkled surfaces. Fourier transform infrared spectroscopy demonstrated that the carbonyl group of TH formed hydrogen bonds with the amide group of CTS and the hydroxyl group of β‐CD. The swelling ability of the two microspheres was more than three times their weight, and their humidity rates attained equilibrium within 24 h. The ciliary beat movement times of CTS and CTS/β‐CD microspheres were 493.00 and 512.33 min, respectively, which indicated that the two microspheres effectively reduced the ciliotoxicity and possessed better adaptability. In vitro release of TH from CTS/β‐CD microspheres was slower than that from CTS microspheres at pH 6.8 and provided a sustained release of 72.0% within 12 h. The results suggest that CTS/β‐CD microspheres are a promising carrier for sustained release for pulmonary delivery. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1183–1190, 2007     

Preparation of surface‐modified,micrometer‐sized carboxymethyl chitosan drug‐loaded microspheres

Drug‐loaded microspheres have attracted much attention in embolization therapy for liver cancer in recent years. Carboxymethyl chitosan has obvious advantages for biomedical applications because of its exceptional biocompatibility and biodegradability. In this study, surface‐modified carboxymethyl chitosan microspheres were prepared by the crosslinking reactions of carboxymethyl chitosan in a reverse suspension system with poly(ethylene glycol diglycidyl ether) (PEGDE) as the crosslinking agent; this was followed by the grafting polymerization of 2‐acrylamido‐2‐methyl propane sulfonic acid on the surface of the microspheres. The microspheres showed regular spherical shapes with size distributions ranging from 300 to 600 μm. Ion‐exchange groups (? COOH, ? SO₃H) were introduced into the microspheres; these groups could load doxorubicin with a loading rate as high as 34.6% in 24 h. This was an increase of 49.8% compared to that of the pure carboxymethyl chitosan microspheres. Additionally, the microspheres possessed large network structures because macromolecular PEGDE was used as the crosslinking agent. The drug‐release profile showed that the surface‐modified microspheres displayed a sustained‐release manner compared with the nonmodified microspheres in phosphate‐buffered saline. These microspheres have promising applications as drug‐loaded arterial embolization agents for the interventional treatment of tumors. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45731.     

Synthesis and surface properties of polystyrene‐graft‐poly(ethylene glycol) copolymers

Polystyrene‐graft‐poly(ethylene glycol) copolymers (PS‐g‐PEG) were successfully synthesized using the “grafting‐through” method. The graft copolymers and the surface properties of their coats were characterized by 1 H‐NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), static contact angle measurement, and atomic force microscopy (AFM). Both DSC and TEM indicated that the graft copolymers had a microphase separated structure. AFM showed the microphase separated structure also occurred at the coat surface, especially at high PEG content, which could also be indirectly confirmed by the XPS and contact angle results. The formation mechanism of the microphase separated structure was discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1458–1465, 2007     

Synthesis of collagen‐modified polylactide and its application in drug delivery

In this article, collagen modified polylactide (CPLA) was synthesized by means of graft modification, and its structure was confirmed by FTIR and FITC‐labeled fluorescence spectra. Subsequently, the performance of CPLA was characterized with hydrophilicity test and degradability test. After that, the aspirin sustained release microspheres of the synthetic copolymers were prepared via the emulsion‐solvent evaporation technique, followed with its measurements of morphology, size, and encapsulation efficiency. Finally, the controlled release properties of the obtained microspheres were investigated. The results showed that the aspirin sustained release microspheres exhibited well‐defined morphology with smooth spherical surface, with average size of 3.990 μm and encapsulation efficiency of 51.83%. Furthermore, compared with aspirin‐loaded PLA microspheres, at the initial 32 h, the drug release was faster for aspirin‐loaded CPLA microspheres favored by its increased hydrophilicity, and then the drug release was slower than that of PLA microspheres because the ? NH₂ group on the introduced collagen inhibited acidic autocatalytic degradation. The results suggested that CPLA showed a great potential as particles for drug delivery. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and evaluation of cellulose acetate butyrate and poly(ethylene oxide) blend microspheres for gastroretentive floating delivery of repaglinide

In this study, hollow microspheres of cellulose acetate butyrate (CAB) and poly(ethylene oxide) (PEO) were prepared by emulsion–solvent evaporation method. Repaglinide was successfully encapsulated into floating microspheres. Various formulations were prepared by varying the ratio of CAB and PEO, drug loading and concentration of poly(vinyl alcohol) (PVA) solution. Encapsulation of the drug up to 95% was achieved. The microspheres tend to float over the simulated gastric media for more than 10 h. The micromeritic properties of microspheres reveal the excellent flow and good packing properties. The % buoyancy of microspheres was found to be up to 87. SEM showed that microspheres have many pores on their surfaces. Particle size ranges from 159 to 601 μm. DSC and X‐RD revealed the amorphous dispersion in the polymer matrix. In vitro release experiments were performed in simulated gastric fluid. In vitro release studies indicated the dependence of release rate on the extent of drug loading and the amount of PEO in the microspheres; slow release was extended up to 12 h. The release data were fitted to an empirical equation to compute the diffusional exponent (n), which indicated that the release mechanism followed the non‐Fickian trend. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Curing kinetics and thermal property characterization of o‐CFER/MeTHPA/O‐MMT nanocomposite

The kinetics of the cure reaction for a system of o‐cresol‐formaldehyde epoxy resin (o‐CFER), 3‐methyl‐tetrahydrophthalic anhydride (MeTHPA), N,N‐dimethyl‐benzylamine, and organic montmorillonite(O‐MMT) were investigated by means of X‐ray diffraction (XRD) and differential scanning calorimetry (DSC). The XRD result indicates that an exfoliated nanocomposite was obtained. The analysis of DSC data indicated the behavior was shown in the first stages of the cure for the system, which could be well described by the model proposed by Kamal. In the later stages, the reaction is mainly controlled by diffusion, and diffusion factor, f(α), was introduced into Kamal's equation. In this way, the curing kinetics was predicted well over the entire range of conversion. Molecular mechanism for curing reaction was discussed. The thermal degradation kinetics of the system were investigated by thermogravimetric analysis (TGA), which revealed that with the increase of O‐MMT content, TG curves shift to higher temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3023–3032, 2006     

Thermal and pH dual‐responsive hydrogels based on semi‐interpenetrating network of poly(N‐isopropylacrylamide) and collagen nanofibrils

Hydrogels with environment‐sensitive properties have great potential applications in the controlled drug release field. In this paper, hybrid hydrogels with semi‐interpenetrating polymer networks (semi‐IPNs), composed of poly(N‐isopropylacrylamide) (PNIPAM) as the thermo‐sensitive component by in situ polymerization and self‐assembled collagen nanofibrils as the pH‐sensitive framework, were prepared for controlled release of methyl violet as a model drug. From Fourier transform infrared spectroscopy and scanning electron microscopy, it was indicated that the crosslinking of PNIPAM in the presence of collagen nanofibrils led to the formation of semi‐IPNs with homogeneous porous structure, and the semi‐IPNs showed improved thermal stability and elastic properties compared with the native collagen as determined using differential scanning calorimetry and rheologic measurements. Furthermore, the semi‐IPNs possessed swelling behaviors quite different from those of neat collagen or PNIPAM hydrogel under various pH values and temperatures. Correspondingly, as expected, the drug release behavior in vitro for semi‐IPNs performed variously compared with that for single‐component semi‐IPNs, which revealed the tunable performance of semi‐IPNs for release ability. Finally the thermo‐ and pH‐responsive mechanism of the semi‐IPNs was illuminated to provide guidance for the application of the thermo‐ and pH‐sensitive collagen‐based hybrid hydrogels in controlled drug delivery systems. © 2019 Society of Chemical Industry     

Thermal and wide angle X‐ray analysis of chemically and radiation‐crosslinked low and high density polyethylenes

Low and high density polyethylenes (PE) were crosslinked by two methods, namely, chemically by use of different amounts of tert‐butyl cumyl peroxide (BCUP) and by irradiation with different doses of electron beam. A comparison between the effects of these two types of crosslinking on crystalline structure, crystallinity, crystallization, and melting behaviors of PE was made by wide angle X‐ray diffraction and DSC techniques. Analysis of the DSC first heating cycle revealed that the chemically induced crosslinking, which took place at melt state, hindered the crystallization process and decreased the degree of crystallinity, as well as the size of crystals. Although the radiation‐induced crosslinking, which took place at solid state, had no significant influence on crystalline region, rather, it only increased the melting temperature to some extent. However, during DSC cooling cycle, the crystallization temperature showed a prominent decrease with increasing irradiation dose. The wide angle X‐ray scattering analysis supported these findings. The crystallinity and crystallite size of chemically crosslinked PE decreased with increasing peroxide content, whereas the irradiation‐crosslinked PE did not show any change in these parameters. As compared with HDPE, LDPE was more prone to crosslinking (more gel content) owing to the presence of tertiary carbon atoms and branching as well as owing to its being more amorphous in nature. HDPE, with its higher crystalline content, showed relatively less tendency toward crosslinking especially by way of irradiation at solid state. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3264–3271, 2006     

Synthesis of novel phosphorous‐containing biphenol, 2‐(5, 5‐dimethyl‐4‐phenyl‐2‐oxy‐1,3,2‐dioxaphosphorin‐6‐yl)‐1,4‐benzenediol and its application as flame‐retardant in epoxy resin

A novel phosphorous‐containing biphenol, 2‐(5,5‐dimethyl‐4‐phenyl‐2‐oxy‐1,3,2‐dioxaphosphorin‐6‐yl)‐ 1,4‐benzenediol (DPODB), was prepared by the addition reaction between 5,5‐dimethyl‐4‐phenyl‐2‐oxy‐1,3,2‐dioxaphosphorinane phosphonate (DPODP) and p‐benzoquinone (BQ). The compound (DPODB) was used as a reactive flame retardant in o‐cresol formaldehyde novolac epoxy resin (CNE) for electronic application. The structure of DPODB was confirmed by FTIR and NMR spectra. Thermal properties of cured epoxy resin were studied using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The flame retardancy of cured epoxy resins was tested by UL‐94 vertical test and achieved UL‐94 vertical tests of V‐0 grade (nonflammable). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3842–3847, 2006