Effect of attapulgite contents on release behaviors of a pH sensitive carboxymethyl cellulose‐g‐poly(acrylic acid)/attapulgite/sodium alginate composite hydrogel bead containing diclofenac

A series of pH‐sensitive composite hydrogel beads, carboxymethyl cellulose‐g‐poly(acrylic acid)/attapulgite/sodium alginate (CMC‐g‐PAA/APT/SA), were prepared by combining CMC‐g‐PAA/APT composite and SA, using Ca²⁺ as the ionic crosslinking agent and diclofenac sodium (DS) as the model drug. The effects of APT content and external pH on the swelling properties and release behaviors of DS from the composite hydrogel beads were investigated. The results showed that the composite hydrogel beads exhibited good pH‐sensitivity. Introducing 20% APT into CMC‐g‐PAA hydrogel could change the surface structure of the composite hydrogel beads, decrease the swelling ability, and relieve the burst release effect of DS. The drug cumulative release ratio of DS from the hydrogel beads in simulated gastric fluid was only 3.71% within 3 hour, but in simulated intestinal fluid about 50% for 3 hour, 85% for 12 hour, up to 90% after 24 hour. The obtained results indicated that the CMC‐g‐PAA/APT/SA hydrogel beads could be applied to the drug delivery system as drug carriers in the intestinal tract. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

Drug releasing characteristics of thermo- and pH-sensitive interpenetrating polymer networks based on poly (N-isopropylacrylamide)

Interpenetrating polymer networks (IPNs) of poly(N-isopropylacrylamide)/polyurethane (PNIPAAm/PU) and poly(N-isopropylacrylamide)/poly(acrylic acid) (PNIPAAm/PAA) were synthesized to investigate the swelling and drug releasing behavior. The presence of urethane network in PNIPAAm/PU IPNs improved the mechanical strength, but reduced the swelling and drug releasing rates because of its hydrophobic characteristics. The swelling transition temperatures of PNIPAAm gels were little affected by the incorporation of PU networks in IPN structures. The drug releasing process was analyzed with a simple exponential expression of time dependent fractional drug release. The swelling and drug releasing behavior of PNIPAAm/PAa IPNs was significantly affected by the variation of PAA compositions. The drug release process changed from anomalous to dual type via zero-order mode with increasing PAA concentration due to the competitive swelling rates between PNIPAAm and PAA during release process. The releasing rate decreased in the buffer solution of pH 7.4, but increased in that of pH 5.0 with increasing PAA concentration at both 28 and 37°C because the swelling power of PAA in pH 5.0 was much less than that in pH 7.4. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2647–2655, 1997     

Development of tunable biodegradable polyhydroxyalkanoates microspheres for controlled delivery of tetracycline for treating periodontal disease

This article was aimed at preparation and characterization of drug delivery carriers made from biodegradable polyhydroxyalkanoates (PHAs) for slow release of tetracycline (TC) for periodontal treatment. Four PHA variants; polyhydroxybutyrate (PHB), poly(hydroxybutyrate‐co‐hydroxyvalerate) with 5, 12, and 50% hydroxyvalerate were used to formulate TC‐loaded PHA microspheres by double emulsion‐solvent evaporation method. We also compared the effect of different molecular weight (M_w) of polyvinyl alcohol (PVA) acting as surface stabilizer on particle size, drug loading, encapsulation efficiency, and drug release profile. The TC‐loaded PHA microspheres exhibited microscale and nanoscale spherical morphology under scanning electron microscopy. Among formulations, TC‐loaded PHB:low M_w PVA demonstrated the highest TC loading with slow release behavior. Our results showed that the release rate from PHA microspheres was influenced by both the type of PHA and M_w of PVA stabilizer. Lastly, TC‐loaded PHB microspheres showed efficient killing activity against periodontitis‐causing bacteria, suggesting its potential application for treating periodontal disease. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44128.     

Drug transport in stimuli responsive acrylic and methacrylic interpenetrating polymer networks

The interpenetrating polymer networks (IPNs) are recently gaining attention as sustained drug delivery systems because they could ensure a proper combination of functionality and network density to control the drug release profiles. This study aims to reveal how the functionality of two IPNs based on polyacrylamide and respectively poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA) influences their smart behavior as well as their properties as delivery systems of the cationic drug verapamil hydrochloride (VPM). The “extra” α‐methyl group of PMAA results into a loss of the temperature sensitivity in the studied region and changes the pH responsivity of the PMAA/PAAM IPNs as compared to the PAA/PAAM IPNs. Moreover, the VPM diffusion in both IPNs depends on their composition due to the change in their functionality as well as of their network density. The “extra” α‐methyl group of PMAA defines its enhanced hydrophobicity and hence influences the VPM diffusion mechanism. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45380.     

Preparation,evaluation, and in vitro release study of O‐carboxymethyl chitosan nanoparticles loaded with gentamicin and salicylic acid

To inhibit the ototoxicity of gentamicin (GM) and overcome the drawback related to chitosan (CS) nanoparticles preparation in acid solution, O‐carboxymethyl chitosan (O‐CMC) nanoparticles loaded with GM and salicylic acid (SA) were prepared by ionic cross‐linking method using calcium chloride as crosslinking agent. The Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) were used to analyze the reaction of O‐CMC and crosslinking agent. The parameters of preparation of the compound nanoparticles including the concentration of O‐CMC, the mass ratio of O‐CMC to calcium chloride, and the feed ratio of SA to GM were investigated. The results showed that the obtained nanoparticles had a high zeta potential and drug‐loading capacity. The nanoparticles were characterized by a spherical morphology, with average size ranging from 148 to 345 nm and a narrow particle size distribution. In vitro release studies in phosphate buffer saline (pH 7.4) evidenced a burst release in the first 1 h, followed by a sustained release in the residual time. The release amount of SA and GM were approximately equal in 24 h, which indicated that the SA‐ and GM‐loaded O‐CMC nanoparticles are a promising carrier system for inhibiting the ototoxicity of GM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Ionizable interpenetrating polymer networks of carboxymethyl cellulose and polyacrylic acid: Evaluation of water uptake

A semi interpenetrating polymer network (IPN) of carboxymethyl cellulose (CMC) and crosslinked polyacrylic acid (PAA) has been prepared and its water‐sorption capacity has been evaluated as a function of chemical architecture of the IPN, pH, and temperature of the swelling medium. The water uptake potential of the IPNs has also been investigated in inorganic salt containing aqueous solutions and simulated biological fluids. The IPN was characterized by IR spectral analysis, and the network parameters such as average molecular weight between crosslinks (M_c), crosslink density (q), and number of elastically effective chains (V_e) have been evaluated by water‐sorption measurements. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2054–2065, 2004     

Miscibility of poly(acrylic acid)/poly(methyl vinyl ketone) blend and in vitro application as drug carrier system

A series of poly(acrylic acid)/poly(methyl vinyl ketone) (PAA/PMVK) blends with different compositions were prepared by the solvent casting method. The miscibility of this pair of polymers was investigated by differential scanning calorimetry(DSC), Fourier transform infra-red (FTIR) and X-Ray diffraction (XRD) techniques. An in-vitro cytotoxicity test of the drug-carrier system via MTT (3-(4,5-demethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed no significant cytotoxic effects at concentrations up to 100 µg· ml^?1. The STX/PAA-50 drug carrier systems were also prepared by solvent casting of solutions containing the sulfamethoxazole (STX) used as drug model and PAA/PMVK blend in N.N-dimethylformamide then crosslinked with acidified ethylene glycol. The release dynamic of STX from the prepared hydrogels was investigated in which the diffusion through the polymer matrix, the enhancement of the water solubility of STX, the influence of the initial drug concentration, the pH of the medium, and the effect of the degree of swelling of the polymer matrix on the release dynamic was evaluated. According to the total gastrointestinal transit time estimated by Belzer, the estimate distribution of STX released in the different organs indicated that the performance is obtained with the drug – carrier-system containing equal ratios of polymer and 10 wt% of STX (STX-10/PAA-50).     

Comparative delivery of Diltiazem hydrochloride through synthesized polymer: Hydrogel and hydrogel microspheres

In this study, interpenetrating polymer network (IPN) hydrogel based on polyvinyl alcohol (PVA) networking with polyacrylic acid (PAA) were prepared by a non‐conventional emulsion method without any added crosslinker, using benzoyl peroxide as initiator and sodium chloride (NaCl) as additive. The IPN hydrogel was characterized by using Fourier transformed infrared (FTIR) spectrophotometry, Thermo gravimetric analysis (TGA), and Scanning electron microscopy (SEM). (PVA‐co‐PAA)/NaCl normal IPN hydrogel (H) were fabricated into hydrogel microspheres (HM) by modified emulsion crosslinking method using glutaraldehyde‐saturated toluene as crosslinker and were loaded with Diltiazem hydrochloride (DL). The IPN hydrogel showed more swelling in simulated intestinal fluid (SIF). (PVA‐co‐PAA)/NaCl HM formulation A1 showed comparatively higher DL entrapment (79%) and better control over DL release up to 24 h. By comparing antihypertensive activity of DL loaded two formulations in normotensive rats, HM formulation A1 found more effective in reducing blood pressure to 40.1%. The experimental results demonstrated that (PVA‐co‐PAA)/NaCl HM had the greater potential than normal hydrogel to be used as a drug carrier. A single use of the prepared hydrogel microsphere system of DL can effectively control hypertension in rats. The system holds promise for clinical studies. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Carboxymethylchitin Nanocarrier (CMCNC): A Novel Therapeutic Formulation for Drug Release

In the present work, chitin based derivatives carboxymethylchitin, CMC were synthesised for nanocarriers (NCs). Cu and Fu loaded NCs had also been prepared and characterized by various physiochemical & biological techniques. Here, drug release profiles and drug kinetics were also studied. In vitro cytotoxicity test (Cell Viability-A549 cells) result found most effected. CMCNC also fitted best in Higuchi model which proved that this prepared nanocarriers followed the mechanism of diffusion rather than dissolution and degradation. The overall analysis leads to the conclusion that CMCNC found to be a suitable nanocarrier for targeted drug delivery.     

pH响应性PAA/毒死蜱/氨基化介孔硅缓释体系的制备与性能

以共缩聚法合成氨基化介孔硅,采用浸渍法制备毒死蜱/氨基化介孔硅,并以带负电荷的聚丙烯酸（PAA）为功能分子,通过静电吸附作用制备了具有pH响应的PAA/毒死蜱/氨基化介孔硅缓释体系。利用XRD、N₂吸附-脱附、TEM、SEM、TG、Zeta电位和FTIR对PAA/毒死蜱/氨基化介孔硅的结构进行了表征,并探究了其在不同pH和温度下的释药行为。结果表明,PAA通过静电作用包覆于毒死蜱/氨基化介孔硅的表面。缓释体系的药物释放主要受到PAA的阻碍作用,PAA修饰载药氨基化介孔硅显示出明显的pH响应性,当pH≤7时,其药物释放速率随pH减小而增大,而在偏碱性条件下的释药速率稍大于中性环境。同时,载药体系的释药速率还受到温度的影响。其释药行为可用Korsmeryer-Pappas动力学模型来描述。     

Biodegradable hollow microfibres to produce bioactive scaffolds

Biodegradable hollow microfibres containing particles loaded with specific active agents can be potentially employed to produce a special kind of substrate for tissue engineering, able to function as a scaffold and at the same time to act as a drug‐releasing system. Biodegradable hollow microfibres based on poly(lactic acid) were produced by a dry–wet spinning procedure. Drug‐loaded microparticles were prepared by a simple oil‐in‐water emulsion and entrapped inside the fibres. The morphology of both fibres and particles was investigated by scanning electron microscopy. The mechanical and thermal properties of the fibres were investigated by tensile tests and differential scanning calorimetry. In vitro tests were performed to evaluate the release of the drug from the fibres loaded with the particles Copyright © 2004 Society of Chemical Industry     

Calcium‐carboxymethyl chitosan hydrogel beads for protein drug delivery system

In this study, carboxymethyl chitosan (CMC) hydrogel beads were prepared by crosslinking with Ca²⁺. The pH‐sensitive characteristics of the beads were investigated by simulating gastrointestinal pH conditions. As a potential protein drug delivery system, the beads were loaded with a model protein (bovine serum albumin, BSA). To improve the entrapment efficiency of BSA, the beads were further coated with a chitosan/CMC polyelectrolyte complex (PEC) membrane by extruding a CMC/BSA solution into a CaCl₂/chitosan gelation medium. Finally, the release studies of BSA‐loaded beads were conducted. We found that, the maximum swelling ratios of the beads at pH 7.4 (17–21) were much higher than those at pH 1.2 (2–2.5). Higher entrapment efficiency (73.2%) was achieved in the chitosan‐coated calcium‐CMC beads, compared with that (44.4%) in the bare calcium‐CMC beads. The PEC membrane limited the BSA release, while the final disintegration of beads at pH 7.4 still leaded to a full BSA release. Therefore, the chitosan‐coated calcium‐CMC hydrogel beads with higher entrapment efficiency and proper protein release properties were a promising protein drug carrier for the site‐specific release in the intestine. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3164–3168, 2007     

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     

In vitro release dynamics of an anticancer drug from swellable gelatin nanoparticles

Gelatin (Type A) nanoparticles were prepared by a single W/O emulsion technique and characterized by infrared (IR) spectra, scanning electron microscopy (SEM), and particle size analysis. The IR spectra clearly confirmed the presence of gelatin and cytarabine in the loaded nanoparticles while the scanning electron micrograph (SEM) image depicts smooth surface, spherical shape and uneven size of nanoparticles (100–300 nm). The prepared nanoparticles were loaded with cytarabine, a well‐known anticancer drug, and the release dynamics of entrapped drug was investigated as a function of various experimental factors, such as percent loading of the drug, chemical architecture of the nanocarriers, and pH, temperature, ionic strength, and nature of the release medium. The nanoparticles were also studied for their water sorption capacity by optical microscopic method taking advantage of the aggregation of nanoparticles. The drug release process was analyzed kinetically using Ficks power law, and a correlation was established between the quantity of released drug and swelling of the nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2320–2332, 2006     

Synthesis,characterization, and drug‐release behavior of amphiphilic quaternary ammonium chitosan derivatives

A new type of amphiphilic quaternary ammonium chitosan derivative, 2‐N‐carboxymethyl‐6‐O‐diethylaminoethyl chitosan (DEAE–CMC), was synthesized through a two‐step Schiff base reaction process and applied to drug delivery. In the first step, benzaldehyde was used as a protective agent for the incorporation of diethylaminoethyl groups to form the intermediate (6‐O‐diethylaminoethyl chitosan). On the other hand, NaBH₄ was used as a reducing agent to reduce the Schiff base, which was generated by glyoxylic acid, for the further incorporation of carboxymethyl groups to produce DEAE–CMC. The structure, thermal properties, surface morphology, and diameter distribution of the resulting chitosan graft copolymers were characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, thermogravimetric analysis, differential scanning calorimetry, X‐ray powder diffraction, scanning electron microscopy, and laser particle size analysis. Benefiting from the amphiphilic structure, DEAE–CMC was able to be formed into microspheres in aqueous solution with an average diameter of 4.52 ± 1.21 μm. An in vitro evaluation of these microspheres demonstrated their efficient controlled release behavior of a drug. The accumulated release ratio of vitamin B₁₂ loaded DEAE–CMC microspheres were up to 93%, and the duration was up to 15 h. The grafted polymers of DEAE–CMC were found to be blood‐compatible, and no cytotoxic effect was shown in human SiHa cells in an MTT [3‐(4, 5‐dimethyl‐thiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide] cytotoxicity assay. These results indicate that the DEAE–CMC microspheres could be used as safe, promising drug‐delivery systems. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39890.     

Insolubilization of sodium chondroitin sulfate by forming a semi‐interpenetrating polymer network with acrylic acid: A potential carrier for colon‐specific drug delivery

To reduce the highly hydrophilic property of chondroitin sulfate (ChS), a semi‐interpenetrating polymer network (semi‐IPN) of chondroitin sulfate/polyacrylic acid (PAA) was prepared as a drug carrier by crosslinking acrylic acid with diethyleneglycol diacrylate. The swelling properties of the semi‐IPNs with different concentrations of crosslinking agent were correlated. The moisture sorption profiles were evaluated using differential thermal analysis. Ketoprofen was used as a drug probe to evaluate the performance of the drug released from the semi‐IPN matrices. The prepared semi‐IPNs demonstrated significant swelling reduction properties with both gastric and intestinal fluids compared with those of both the pure ChS and the ChSAA blend without the crosslinking agent. The amount of accumulated drug released from the semi‐IPNs was less than 30 wt % at pH 1.2 and up to 80 wt % at pH 7.4. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 114–122, 2002     

Development and evaluation of pH-dependent interpenetrating network of acrylic acid/polyvinyl alcohol

The objective of the present work was to synthesize interpenetrating networks (IPNs) of acrylic acid/polyvinyl alcohol (AA/PVA) by free radical polymerization using N,N-methylenebisacrylamide (MBAAm) and glutaraldehyde as cross-linkers. The IPNs were evaluated for swelling, diffusion coefficient and network parameters by using Flory–Huggins theory, i.e., the average molecular weight between cross-links (M _c), polymer volume fraction in swollen state (V _2,s), number of repeating units between cross-links (M _r) and cross-linking density (N). It was found that the degree of swelling of AA/PVA interpenetrating network increases greatly within the pH range 5–7 depending on composition. The gel fraction and porosity increased by increasing the concentration of AA or PVA, while by increasing the degree of cross-linking, porosity decreased and gel fraction increased. Selected samples were loaded with chlorpheniramine maleate as a model drug. Drug release was studied in USP, hydrochloric acid buffer solution of pH 1.2 and phosphate buffer solutions of pH 5.5 and 7.5. Drug release data were fitted into various kinetics models, e.g., zero-order, first-order, Higuchi and Peppas models. The results of the kinetics investigation showed that the drug release from IPNs followed non-Fickian diffusion. Fourier transform infrared spectra confirmed the formation of cross-linked IPNs as there was a shifting to lower frequency of 1,713–1,718 cm^?1 with reduced intensity, while scanning electron microscopy revealed uniform distribution of drug in IPNs.     

Nitrofurazone‐loaded PVA–PEG semi‐IPN for application as hydrogel dressing for normal and burn wounds

Hydrogels have been used in a wide variety of biomedical devises, particularly in the field of drug delivery, tissue engineering, and wound healing. In this study, a polyvinyl alcohol (PVA)–polyethylene glycol (PEG) semi‐interpenetrating hydrogel network (IPN)‐based wound dressing system containing nitrofurazone (NFZ) was synthesized by chemical crosslinking technique. The introduction of PEG to PVA matrix led to reduction in the water vapor transmission rate, which in‐turn resulted in improved healing activity. Drug‐loaded IPNs were prepared by mixing aqueous solution of NFZ with the optimized PVA–PEG formulation subsequent to the crosslinking step. The in vitro diffusion studies of NFZ indicated a relatively slow release of drug resulting from its microencapsulation in the polymeric matrix. Subsequently, in vivo wound healing efficacy toward acute and burn wound healing in experimental rats was investigated. Semi‐IPN hydrogel loaded with NFZ dressing improved the overall healing rate in both acute and burn wounds, as evidenced by significant increase in total protein, hydroxyproline and hexosamine contents. Histological examinations also correlated well with the biochemical findings. A faster wound contraction was also observed in hydrogel treated acute and burn wounds. The results indicated that PVA–PEG semi‐IPN hydrogel based dressing systems containing NFZ could be used as an effective wound dressing material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and Properties of Interpenetrating Polymer Networks Composed of Epoxy Resins and Polysulphones with Cross-linkable Pendant Vinylbenzyl Groups

Polysulphones with cross-linkable pendant vinylbenzyl groups (PSF-VB) were prepared via chloromethylation of commercial polysulphones. The curing reactivity of PSF-VB was investigated by differential scanning calori-metry. Interpenetrating polymer networks (IPNs) were prepared based on bisphenol A diglycidyl ether (DGEBA) and PSF-VB, where DGEBA was cured by 4,4′-diaminodiphenyl sulphone and VB groups of PSF-VB were radically polymerized using dicumyl peroxide (DCP). Polysulphones having pendant benzyl groups (PSF-Bz) were also prepared and used as non-reactive modifiers. The fracture toughness (K_IC) for the resulting epoxy/PSF-VB IPN increased by 65% with no loss of mechanical properties on 10wt% addition of PSF-VB (7·9mol% VB unit, MW 74000). Non-reactive PSF-Bz was less effective than PSF-VB. Although the PSF-Bz modified resin had a particulate structure, the morphologies of the PSF-VB/epoxy IPNs were not clear from scanning electron micrographs. Furthermore, the epoxy/PSF-VB IPNs had higher solvent resistance than the epoxy/PSF-Bz blends. Morphological behaviour, modification results and high solvent resistance of the cured epoxy/PSF-VB resins indicate that cross-linked PSF-VB and the epoxy network entangled fully in the presence of DCP. © of SCI.