Co-condensation Reaction Research Articles

In Situ-Doped Sulfonated Schiff-Base Networks in SPEEK Composite Membranes with Enhanced Proton Conductivity.

Sulfonated polyether ether ketone (SPEEK) has been widely investigated in proton exchange membrane fuel cells (PEMFCs) due to its excellent thermal stability, chemical stability, and low cost compared with Nafion. However, excessive degree of sulfonation will easily lead to the decrease in thermal stabilities and mechanical properties of SPEEK membranes, which limits the enhancement of proton conductivity. In this work, a series of Schiff-base networks (SNWs) with different contents are in situ synthesized in the SPEEK membrane by a Schiff-base co-condensation reaction, and then, the composite membranes are soaked in sulfonic acid for further improvement of proton conductivity. The highest doping amount of the SNW filler in SPEEK can reach 20 wt %. High loading and low leaching rate of H2SO4 are easily achieved owing to the similar size between sulfuric acid molecules and micropores in SNW. Moreover, abundant amino and imine groups in SNW networks contribute to the anchoring of H2SO4 into the pores by acid-base interactions. The proton conductivity of the SPEEK/S-SNW-15 composite membrane can reach 115.53 mS cm-1 at 80 °C and 100% RH. Meanwhile, the composite membrane also exhibits satisfied stability and mechanical property.

Copper-complexed dipyridyl-pyridazine functionalized periodic mesoporous organosilica as a heterogeneous catalyst for styrene epoxidation.

A new heterogeneous catalyst has been synthesized by immobilization of a copper complex on dipyridyl-pyridazine functionalized periodic mesoporous organosilica (dppz-vPMO). This ordered support was first prepared by a co-condensation reaction between vinyltriethoxysilane and 1,2-bis(trimethoxysilyl)ethane and further post-functionalized through a hetero Diels-Alder reaction with 3,6-di-2-pyridyl-1,2,4,5-tetrazine. Techniques such as XRD, N2 isotherms, TEM, 13C NMR, XPS and DRIFT, among others, were employed to characterize the surface functionalized materials. These results have proven the ordered mesostructure of the materials as well as the presence of novel nitrogen-chelating heterocyclic compounds on the pore surface after the post-modification process. Additionally, the successful anchoring of a copper complex on the dipyridyl-pyridazine (dppz) ligands has been confirmed. The resulting material was evaluated as a heterogeneous catalyst in the epoxidation of styrene using tert-butylhydroperoxide (TBHP) as an oxidant. Under the optimized reaction conditions, Cu@dppz-vPMO showed a high styrene conversion (86.0%) and a remarkable selectivity to styrene oxide (41.9%). Indeed, this catalyst provided excellent catalytic results in terms of stability, reaction rate, conversion and selectivity compared to other bipyridine-like copper catalysts.

Preparation of Novel Nickel Oxide@ Glutamic/Thiosemicarbazide Nanoparticles: Implications for Cytotoxic and Anti-cancer Studies in MCF-7 Breast Cancer Cells

The present study, evaluate the anti-cancer properties of nickel oxide nanoparticles functionalized by glutamic acid and conjugated with thiosemicarbazide (NiO@Glu/TSC). First, the NiO@Glu/TSC nanoparticles were prepared using co-condensation reaction. Different techniques were achieved for confirming the synthesized nanoparticles such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS), DLS (dynamic light scattering) and ZP (zeta potential) analysis. Interestingly, the transmission electron microscopy (TEM) and scanning electron microscopy (SEM) results indicated that the structure and size of NiO@Glu/TSC nanoparticles were spherical ranging from 20 to 80 nm. NiO@Glu/TSC nanoparticles revealed significant growth inhibition of MCF-7 (human breast cancer) cells with IC50 values of 298.33 μg/mL, while no significant toxicity was evaluated in HEK293 (normal human embryonic kidney) cells after using in vitro toxicity method. Compared with HEK293 cells, MCF-7 cells elucidated a higher sensitivity to NiO@Glu/TSC nanoparticles. To determine the induction of apoptosis or necrosis, cells were double stained with fluorescein isothiocyanate (FITC)-Annexin V and Propidium Iodide (PI) and assessed by flow cytometry. Moreover, to elucidate the nuclear change through apoptosis, Hoechst 33258 staining was examined to investigate morphological features in the nuclei of MCF-7 cells. The results firmly suggest that NiO@Glu/TSC nanoparticles can be as a potential therapeutic agent for cancer treatment.

Preparation, characterization, and anticancer efficacy of novel cobalt oxide nanoparticles conjugated with thiosemicarbazide.

Gastric cancer is one of the most common cancers in modern societies. Previous studies have shown that the use of nanoparticle complexes is effective in the treatment of cancer. The aim of this study was to investigate the cytotoxicity and anticancer properties of cobalt oxide (Co3O4) nanoparticles (NPs) functionalized by glutamic acid (Glu) and conjugated with thiosemicarbazide (TSC) on gastric cancer (AGS) cell line. First, the Co3O4@Glu/TSC nanoparticles were synthesized via co-condensation reaction. Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) tests were performed for identifying the morphology, structure, size and functional groups of produced nanoparticles. MTT assay was also performed to evaluate cytotoxicity effect. Moreover, Annexin V/PI staining with flow cytometry analysis, caspase-3 activation assay, and Hoechst 33258 staining was carried out for evaluating apoptosis. The FTIR results showed that the components of Co3O4@Glu/TSC NPs complex were successfully fabricated. Crystallographic structure of Co3O4@Glu/TSC NPs was confirmed by XRD patterns. SEM results indicated that the size of the nanoparticles was in the range of 16-40nm. An EDX spectrum was determined and data explained the existence of cobalt as the prominent element. MTT test results showed that AGS cell life was significantly decreased compared to the control group with increasing concentration of nanoparticles (dose-dependent) (P < 0.05), IC50 = 107.5μg/mL. The results of flow cytometry assay and caspase-3 activity showed that fabricated Co3O4@Glu/TSC NPs induced apoptosis in the treated group. Moreover, Co3O4@Glu/TSC NPs treated AGS cells indicate an increase in the apoptotic characteristics including nuclear fragmentation. In the current work, the promising cytotoxicity and anti-cancer activities of Co3O4@Glu/TSC NPs complex toward gastric cancer (AGS) cell line were showed and it can be suggested for the drug delivery system.

Synthesis and characterization of ureido-containing MQ silicone resin

Ureido-containing MQ silicone resin (U-MTQ) was synthesized by the hydrolysis and co-condensation reaction of ethyl silicate, ureido silane, hexamethyldisiloxane, and divinyltetramethyldisiloxane under the catalysis of hydrochloric acid. U-MTQ was characterized by FT-IR, 1H-NMR, 29Si-NMR, GPC and TGA. The influences of M/Q molar ratio and hydrochloric acid content on the yield and structure of U-MTQ were investigated. The results showed that the M/Q molar ratio of the product calculated from the 29Si-NMR spectrum was much smaller than that in the feed. As M/Q molar ratio in the feed increased, the molecular weight and its distribution index of U-MTQ decreased, and Si-OH content of U-MTQ also decreased, while the structural regularity of U-MTQ was enhanced. With HCl content increasing, the molecular weight and its distribution index of U-MTQ decreased, but the Si–OH content and structural regularity increased. Meanwhile, the yield first increased and then decreased, and reached the highest value of 71.9% when HCl content was 2.10%. Compared with MQ, the onset weight loss temperature of U-MTQ decreased from 237 °C to 158 °C, and the residue at 900 °C increased from 3.5% to 29.5%.

Amine functionalized mesoporous hybrid materials: influence of KCl and xylene on the textural characteristics and CO2 sorption

Amine-functionalized mesoporous silica materials were prepared by sol–gel method in the system tetraethylortosilicate: bis[(3- trimethoxysilyl)propyl]amine (TEOS: BTPA). The hybrid amine functionalized silica materials were synthesized by co-condensation reaction between TEOS and BTPA precursors in acidic media. Soft template approach for pore formation was applied and as a structural directing agent was used surfactant Pluronic P123. For improving of pore ordering and textural characteristics xylene and KCl were used and their influence on the structural and morphological characteristics was investigated by FTIR, 13C CP MAS NMR, 29Si MAS NMR, BET, PSD and XRD techniques. CO2 adsorption properties of the synthesized amine functionalized hybrid materials were investigated. The simultaneous presence of xylene and KCl leads to improvement of the pore ordering, increasing of the textural characteristics values and formation of cylindrical pores. The determined heats of CO2 adsorption evidenced chemisorption process between CO2 and the amine groups of the hybrid materials.

Halides of the Heavier Group 14 Homologues Germanium, Tin, and Lead-A Journey through Unusual Compounds and Oxidation States.

Classical halides of the heavier Group 14 homologues germanium, tin, and lead are common precursors for the synthesis of exciting compounds, such as polyhedral clusters. To get access to larger metalloid cluster compounds of Group 14, the disproportionation reaction of metastable monohalide solutions, accessible through a preparative co-condensation reaction, proved to be quite successful. As the identity of the subvalent halides within the metastable solutions were yet unknown the reaction course from a monohalide precursor to a metalloid cluster was mostly unidentified. This might change now, as a first subhalide cluster [Ge14 Br8 (Et3 P)4 ] could be characterized, being the first trapped intermediate of the disproportionation reaction of Group 14 subhalides. All these aspects are included within this Minireview, together with a short historical overview, dealing with the development of the preparative co-condensation technique out of the matrix isolation technique, being the essential first step of the synthesis of metastable monohalide solutions of the heavier Group 14 elements Ge and Sn.

Highly fluorinated and hierarchical HNTs/SiO2 hybrid particles for substrate-independent superamphiphobic coatings

In this study, superamphiphobic coatings were prepared using a spray-coating method based on highly fluorinated and hierarchical-structure halloysite nanotubes (HNTs)/SiO2 powder. The prepared superamphiphobic coatings could repel liquids with a surface tension as low as 20.1 mN/m (n-heptane). The coating could repel hot water and 68% HNO3, demonstrating excellent superamphiphobic properties. The superamphiphobic HNTs/SiO2 particles were synthesized using a co-condensation reaction and thiol-ene click reaction. These particles possessed a rod-dot micro-/nano-hierarchical structure and a high F content (52.14 at%), which are essential for superamphiphobicity. The spray-coating method was applied to various substrates using a glue and particle system, exhibiting substrate-independent characterization. Moreover, the coatings also showed excellent mechanical, environmental, and chemical durability under harsh conditions. Multiple features, including anti-corrosion, self-cleaning, and antifouling, rendered the coating suitable for applications in numerous fields.

The ultra-high NO2 response of ultra-thin WS2 nanosheets synthesized by hydrothermal and calcination processes

Ultra-thin WS2 nanosheets with a thickness of about 5 nm were synthesized by an economical hydrothermal method and the following calcination process. A three dimensional wall-like structure was formed by the interconnecting WS2 nanosheets. The growth mechanism of as-prepared WS2 nanosheets was discussed, and it was deduced that mesolamellar tungsten sulfide (WS-L) with intercalated CTA+ cations was formed by co-condensation reaction of WS42− and CTAB in the hydrothermal process. The resistive gas sensors based on as-prepared WS2 nanosheets showed a p-type character, achieved a superior response of 9.3% to 0.1 ppm NO2 gas at room temperature (25 °C) and a good stability in low and moderate humidity. The excellent NO2 sensing properties can be attributed to the ultra-thin nanostructure of the WS2 nanosheets.

The Reaction between Furfuryl Alcohol and Model Compound of Protein.

To guide the preparation of protein-based adhesive, especially the soy-based adhesive, the reaction between a simple dipeptide N-(2)-l-alanyl-l-glutamine (AG), being used as a model compound of protein, and its cross-linker furfuryl alcohol were studied in this paper. The products that were prepared with furfuryl alcohol and AG under different pHs were analyzed by ESI-MS, 13C NMR, and FT-IR. It was found that the medium environment had great effects on the competition of the co-condensation reaction between furfuryl alcohol and AG and self-condensation reaction of furfuryl alcohol molecules in the mixing system with furfuryl alcohol and AG. Under alkaline conditions, both co- and self-condensation were not obviously detected. Only when the value of pH was higher than 11, were a few co-condensation reaction products gotten. The reaction occurred mainly between furfuryl alcohol and the primary amido groups of AG. Under acid conditions, both co- and self-condensation were observed. The more acid the preparation conditions were, the easier to be observed the self-condensation of furfuryl alcohol molecules would be than the co-condensation between furfuryl alcohol and AG. When the value of pH was higher than 5, both co- and self-condensation were not outstanding. In this study, under pH 3, the co- and self-condensation found equilibrium. There was a great possibility for the primary amido and aliphatic amino groups of AG molecules to react with furfuryl alcohol molecules. No reaction was detected between the secondary amido groups of AG and furfuryl alcohol.

Influence of thiol groups on the ethylene adsorption and conductivity properties of the modified porous clay heterostructures (PCHS) using as ethylene scavenger in smart packaging

Porous Clay Heterostructures (PCHs) were prepared by the surfactant-directed assembly of silica source (tetraethylorthosilicate–TEOS) and sodium–bentonite (Na-BTN) clay. These PCHs were subsequently modified to an organic–inorganic hybrid material by the co-condensation reaction of TEOS with (3-mercaptopropyl trimethoxy silane (MPTMS) in 1:1, 2:1, and 4:1 molar ratios of MPTMS to TEOS to obtain conductive porous clays, here referred to as modified MPPCHs. Various weight percentage of MPPCHs at 1, 3, and 5 wt% were blended with polypropylene (PP) and fabricated into the PP/modified MPPCHs nanocomposite films. Analysis revealed that the surface areas of modified MPPCHs increased significantly from Na–BTN; however, the higher MPTMS contents resulted in less porous surface areas. An ethylene adsorption study showed that modified MPPCHs exhibited higher adsorption efficiency of ethylene gas than that of Na–BTN due to the non-polar property of the modified functional groups. Subsequently, the electrical conductivity of the modified MPPCHs with various contents of thiol group was investigated to evaluate potential use in ethylene scavenger/sensor applications.

A facile and low-cost preparation of durable amphiphobic coatings with fluoride–silica@poly(methacrylic acid) hybrid nanocomposites

Poor robustness, high cost and complicated preparation are the main barriers to the large-scale industrial application of amphiphobic coatings. A facile and low-cost method to fabricate durable amphiphobic coatings is reported in this work. The coatings were composed of top and bottom paints. The top paint was prepared by the F–Si@PMAA hybrid nanocomposites dispersion. The hybrid nanocomposites with dual structure were prepared via the co-condensation reaction of tetraethoxysilane (TEOS) and 1H,1H,2H,2H-Perfluorodecyl triethoxysilane (HDFTES) on the surface of the presynthesized PMAA nanoparticles in ethanol dispersion. The bottom one was a type of inexpensive car refinishing paint. The resulting coatings could be sprayed onto different substrates. All the coated substrates exhibited good amphiphobicity with superhydrophobicity with the water contact angle greater than 150°, water roll-off angle less than 4°, and high oleophobicity with the oil contact angle greater than 130°. Moreover, all of the prepared coatings exhibited great robustness after water jetting, sand abrasion, and knife scratching. This method can be an effective strategy for fabricating amphiphobic surfaces for practical industrial applications.

From a Two-Dimensional Supramolecular Network to One-Dimensional Covalent Polymer at the Liquid/Solid Interface: Insight into the Role of the Stoichiometric Ratio of the Precursors

Co-condensation reaction between 2,6-diaminoanthraquinone and aromatic aldehyde at the octanoic acid/highly oriented pyrolitic graphite (HOPG) interface has been studied with scanning tunneling microscopy (STM). We found that the stoichiometric ratio of the precursors plays a vital role in the formation of the assembling structures. By controlling the molar ratio of the amine and aldehyde monomers, either an ordered, hydrogen-bond-stabilized two-dimensional supramolecular network or assembly of one-dimensional covalent polymers can be successfully constructed. The supramolecular network can also be transformed to covalent polymers by annealing the sample to 373 K.

A 13C-NMR Study on the 1,3-Dimethylolurea-Phenol Co-Condensation Reaction: A Model for Amino-Phenolic Co-Condensed Resin Synthesis.

The reactions of di-hydroxymethylurea with phenol under alkaline (pH = 10), weak (pH = 6) and strong acidic (pH = 2) conditions were investigated via the 13C-NMR method. Based on the proposed reaction mechanisms, the variations of the structures of different condensed products were analyzed and the competitive relationship between self- and co-condensation reactions was elucidated. The required experimental conditions for co-condensations were clearly pointed out. The main conclusions include: (1) the self-condensation between urea formaldehyde (UF) or phenol formaldehyde (PF) monomers were dominant while the co-condensations were very limited under alkaline conditions. This is because the intermediates produced from urea, methylolurea and phenol are less reactive in co-condensations with respect to self-condensations; (2) under weak acidic conditions, the self-condensations occurred exclusively among the UF monomers. The co-condensation structures were not observed; and (3) the co-condensations became much more competitive under strong acidic conditions as the relative content of the co-condensed methylenic carbon accounts for 53.3%. This result can be rationalized by the high reactivity of the methylolphenol carbocation intermediate toward urea and methylolurea. The revealed reaction selectivity and mechanisms may also be applied to the synthesis of those more complex co-condensed adhesives based on natural phenolic and amino compounds.

In vitro and in vivo assessment of EDTA-modified silica nano-spheres with supreme capacity of iron capture as a novel antidote agent

Mesoporous silica nanoparticles having structure of MCM-41 category with amine and EDTA functional groups in the pores were prepared using a co-condensation reaction. The synthetic steps eventuated in the mesoporous silica nanoparticles with spherical sizes lower than 50nm supposed to have high surface area. The nanoparticles' structure and functionality were characterized by FTIR spectroscopy and CHN analysis and the topography were examined by SEM and TEM and hydrodynamic sizes were demonstrated by DLS. The crystallinity and mesoporous pattern were figured out by XRD technique. Then the efficiency of these materials was tested in vitro and in vivo in adsorbing ferrous sulfate which is a supplement normally prescribed in treating iron deficiency and its overdose is potentially lethal, especially in young children. In vivo experiments illustrated that both nanoparticles could efficiently be administrated as an antidote agent against iron overdose, but EDTA-MSN nanoparticles were superior to NH2-MSN nanoparticles.

Dye photodegradation employing mesoporous organosilicas functionalized with 1,8-naphthalimides as heterogeneous catalysts

Abstract Mesoporous organosilicas containing covalently bound 1,8-naphthalimides (NI) were shown to be efficient heterogeneous catalysts for the photodegradation of methylene blue (MB), a typical textile pollutant. The NI-containing mesoporous silicas (SBANI materials) were prepared by a co-condensation reaction, in conditions similar to those used for inorganic SBA-15. For the photocatalytic tests, the SBANI materials were suspended in aqueous MB solutions, and the suspensions were irradiated with a 100 W Hg lamp (bandpass filter: 320–480 nm). The activity of the SBANI catalysts was proportional to the NI content in the sample. When MB was irradiated in the presence of a sample with high NI content, total bleaching of MB was observed after 300 min irradiation. In addition, blue shifts in the visible MB band were observed during irradiation. The results can be explained by concomitant mineralization and N -demethylation of MB. N -demethylation led to the formation of azure dyes, which were detected in the reaction mixtures after irradiation. The photocatalytic activity can be attributed to the formation of NI triplets, which can react with MB by both Type (II) (via oxygen reactive species) and Type I (via electron transfer) mechanisms.

Preparation of magnetic graphene/mesoporous silica composites with phenyl-functionalized pore-walls as the restricted access matrix solid phase extraction adsorbent for the rapid extraction of parabens from water-based skin toners

In this work, phenyl-functionalized magnetic graphene/mesoporous silica composites (MG-mSiO2-Ph) were prepared and applied as restricted access matrix solid phase extraction (RAM-SPE) adsorbents to determine the parabens in commercially available retail cosmetics. MG-mSiO2-Ph composites were synthesized by a surfactant-mediated co-condensation reaction in which mesoporous silica with phenyl-functionalized pore-walls was coated on a magnetic graphene sheet. The obtained nano-composites were proven to be of sufficient quality for an ideal RAM-SPE adsorbent with a large specific surface area of 369m2g−1, uniform mesopores of 2.8nm, and special phenyl-functionalized pore-walls. Parabens, such as methyl paraben, ethyl paraben and propyl paraben, were extracted from water-based skin toners using one step of the RAM-SPE and were then analysed by a HPLC-DAD system. The SPE conditions were optimized by studying the parameters, such as the adsorbent amount, elution solvent type, adsorption time and desorption time, that influence the extraction efficiency. For each analyte, there were good linearities of approximately 0.10–120μgmL−1 with determination coefficients (R2)>0.995. The sensitivity was as low as 0.01–0.025μgmL−1 for the LOD, and the percent recoveries were 98.37–105.84%. The intra-day and inter-day RSDs were 1.44–6.11% (n=6) and 3.12–11.70% (n=6), respectively. The results indicated that this method with novel RAM-SPE adsorbents is sensitive and convenient. The results also offered an attractive alternative for the extraction and determination of paraben preservatives in a complex matrix, such as cosmetics.

A magnetically recoverable nanocatalyst based on functionalized mesoporous silica

A magnetically separable 2D-hexagonally ordered thiol functionalized mesoporous silica material (Fe@TFMS) has been synthesized through co-condensation reaction of 3-mercaptopropyltriethoxysilane (MPTES) and tetraethylorthosilicate (TEOS) using cetyltrimethylammonium bromide (CTAB) as a cationic surfactant followed by immobilization of Fe3O4 nanocrystallies at the functionalized mesopore surface. Powder X-ray diffraction (XRD), N2 adsorption/desorption analysis, FT-IR, TEM, FE-SEM, TGA/DTA, CHNS, XPS and NH3-TPD tools are employed to characterize the materials. This functionalized mesoporous material exhibited high catalytic activity in the biodiesel production from a wide range of long chain fatty acids and soybean oil. The material showed high Lewis acidity of 1.02mmolg−1 with a good Brunauer–Emmett–Teller (BET) surface area of 411m2g−1. Fe@TFMS exhibited excellent catalytic efficiency for this esterification reaction using methanol as a solvent cum reactant under eco-friendly and mild reaction conditions (room temperature, 25°C).

DOPO‐VTS‐based coatings in the realm of fire retardants for cotton textile

ABSTRACTThe work elucidates the feasibility of incorporation of phosphorus‐silicon containing fire retardant (10‐(2‐trimethoxysilyl‐ethyl)‐9‐hydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide [DOPO‐VTS]) into nanosol coating solutions by cohydrolysis cocondensation reaction of DOPO‐VTS with tetraethoxysilane precursor (TEOS). Impregnation of cotton with the organophosphorus silane in a form of nanosol dispersion afforded better fire retardancy of such samples compared to pure DOPO or TEOS‐treated cotton indicating synergism between phosphorus and silicon containing species in a condensed phase. The detailed analysis by TGA‐MS and SEM pointed to the fact that DOPO‐VTS acts as a promoter of cotton degradation which, in turn, results in acceleration of the charring process and formation of compact char in contrast to TEOS‐treated samples. Further analysis of the char by XPS confirmed high content of carbonaceous residue in the case of DOPO‐VTS‐treated samples while mainly siliceous component was left in the char in case of cotton treated with TEOS. Standard flammability test (EN ISO 15025:2008) additionally confirmed the absence of smoldering and better overall fire performance of the DOPO‐VTS samples in contrast to TEOS‐treated samples. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41955.

13C NMR study on the structure of ZnO-catalyzed phenol–urea–formaldehyde resin during its synthesis process

The structure of ZnO-catalyzed phenol–urea–formaldehyde (PUF) resin at different synthesis stages was analyzed by liquid 13C nuclear magnetic resonance spectroscopy. The results showed that the general structure of ZnO-catalyzed PUF resin was almost the same as the control PUF resin. Addition reaction between phenol and formaldehyde mainly occurred at the first stage. Total methylol groups amount between phenols of the control resin was a little lower than that of the ZnO-catalyzed PUF resin. Co-condensation and self-condensation reaction occurred at the second stage. The preparation method of ZnO-catalyzed PUF resin favored the co-condensation reaction between phenol methylol groups and urea units, while self-condensation reaction dominated the control resin at the second stage. Formaldehyde completely reacted for both the control and ZnO-catalyzed PUF final resin. The total amount of methylol and methylene groups between urea units and phenols, respectively, was almost the same for the two final resins. The total quantity of methylol groups between phenols represented a continuing downward trend from the first stage to the final stage, and the amount of methylol group (p-Ph–CH2OH) of ZnO-catalyzed PUF resin was 30% more than that of the control resin. Total co-condensed methylene groups amount of ZnO-catalyzed PUF resin was greater than that of the control resin, which indicated that ZnO could make the urea units well incorporated into the co-condensed PUF resin.