Extraction resistance and mechanism of a macromolecular hindered phenol antioxidant in natural rubber

Due to low thermal stability, poor migration, and extraction resistances, the antioxidant with low molecular weight is easy to physically lose during processing and long‐term service, and its applications are severely restricted. To increase the molecular weight of antioxidant is one of the promising methods to overcome such drawbacks. In this study, the extraction resistance of a macromolecular antioxidant, namely polyhydroxylated polybutadiene containing thioether binding 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) (PHPBT‐b‐TPH), was investigated by extraction resistance test and equilibrium swelling experiment. The results exhibited that the PHPBT‐b‐TPH offered much better extraction resistance in natural rubber (NR) than the low molecular weight antioxidant TPH. In addition, the extraction resistance of hydroxyl‐terminated polybutadiene (HTPB), polyethylene glycol (PEG), and polypropylene glycol (PPG) in NR were also compared to study the extraction mechanism of the PHPBT‐b‐TPH. It was found that the higher molecular weight of PHPBT‐b‐TPH and the co‐vulcanization between PHPBT‐b‐TPH and NR were the main reasons for the excellent extraction resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44905.     

Synthesis and Thermo-Oxidative Aging Resistance of Hydroxyl Terminated Polybutadiene Bound 2,2-Thiobis(4-methyl-6-tert-butylphenol)

A novel polymeric antioxidant HTPB-IPDI-TPH was synthesized by the reaction between 2,2-thiobis (4-methyl-6-tert-butylphenol) (TPH) and an adduct (HTPB-IPDI) from hydroxyl terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI). The effects of raw materials ratio and the reaction condition were investigated by measuring the content of the residual –NCO groups of the reactants during the reaction. The structure of HTPB-IPDI-TPH was characterized by FTIR and ¹H NMR. Thermo-oxidative aging resistance of HTPB-IPDI-TPH was evaluated by oxidation induction time (OIT) from DSC of natural rubber vulcanizates. The optimal reaction conditions between IPDI and HTPB were that the amount of dibutyltin dilaurate (DBTDL) was 0.6 wt% based on IPDI, and the temperature and time were 40°C and 270 min, respectively. The reaction conditions between TPH and HTPB-IPDI were that the molar ratio of TPH to –NCO in HTPB-IPDI was 3:1, and the amount of DBTDL was 1.6 wt% based on the total of reactants, and the temperature and time were 75°C and 360 min, respectively. Thermo-oxidative aging resistance of HTPB-IPDI-TPH was obviously superior to the corresponding low molecular counterpart (TPH) for natural rubber vulcanizates.     

Reaction kinetics of dicyclohexylmethane‐4,4′‐diisocyanate with 1‐ and 2‐butanol: A model study for polyurethane formation

Reactions of dicyclohexylmethane‐4,4′‐diisocyanate (H₁₂MDI) with 1‐ or 2‐butanol in N,N‐dimethylformamide using dibutyltin dilaurate (DBTDL), stannous octoate (SnOct), or triethylamine (TEA) as catalyst were conducted in stirred reactors at 40°C. Reactor contents were circulated through an external loop containing a temperature‐controlled FTIR transmission cell; reaction progress was monitored by observing decrease in height of the isocyanate peak at 2266 cm⁻¹. Catalyzed reactions were second order as indicated by linear 1/[NCO] plots; uncatalyzed reactions yielded nonlinear plots. In all cases, the reaction with a primary alcohol was faster than that with a secondary alcohol. DBTDL dramatically increased the reaction rate with both primary and secondary alcohols. For [DBTDL] = 5.3 × 10⁻⁵ mol/L (300 ppm Sn) the second‐order rate constant, k, was 5.9 × 10⁻⁴ (primary OH) and 1.8 × 10⁻⁴ L/(mol s) (secondary OH); for both alcohols, this represents an increase in initial reaction rate on the order of 2 × 10¹ when compared with the uncatalyzed reactions. The second‐order rate constant was observed to increase linearly with DBTDL concentration in the range 100–700 ppm Sn. SnOct and TEA showed little to no catalytic activity with the primary alcohol and only a slight increase in reaction rate with the secondary alcohol. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Iron salen‐catalysed oxidative coupling of phenol derivatives: formaldehyde‐free access to amphiphilic polymers

The oxidative coupling of 4‐tert‐butylphenol ( 1 ), 2,6‐di‐tert‐butyl‐p‐cresol ( 11 ) and 4‐cyanophenol ( 10 ) in the presence of iron salen catalysts (salen = N,N′‐bis(salicylidine)ethylenediamine) and the influence of amine additives on the conversion of 1 were investigated. Furthermore, the activity of the iron complexes was correlated with the substituents at the 5,5′‐positions of the salen ligands. Mechanistically conclusions based on dimer formation in the reaction between 10 and 11 are presented. In the second part of the study the obtained hydrophobic poly(4‐tert‐butylphenol) was modified with Jeffamine^® M‐600, M‐1000 or M‐2070 to give amphiphilic copolymers (18a–c). The amphiphilic copolymers were characterized via size‐exclusion chromatography and dynamic light scattering. The concentration dependence of the cloud point appearance in water of amphiphilic copolymer 18c was analysed via turbidity measurements. © 2016 Society of Chemical Industry     

Kinetics and mechanisms of catalyzed and noncatalyzed reactions of OH and NCO in acrylic polyol–1,6‐hexamethylene diisocyanate (HDI) polyurethanes. VI

Fourier transform infrared spectroscopy was used to study the kinetics of noncatalyzed and catalyzed polyurethanes. These studies show that for noncatalyzed acrylic polyol–hexamethylene diisocyanate (HDI) trimer reactions, the reactions between OH and NCO of HDI exhibit second‐order kinetics, with first‐order kinetics with respect to NCO and OH. On the other hand, when dibutyltin dilaurate (DBTDL) is used as a catalyst in acrylic polyol–HDI trimer reactions, the reaction rate is first order with respect to NCO and 0.5 order in OH and DBTDL concentrations. A mechanism for the catalyzed acrylic polyol–HDI trimer crosslinking reactions is proposed and it appears that an equilibrium involving associations between OH and DBTDL exists, resulting in the formation of an active anion, which interacts with NCO to generate polyurethanes. To further verify this mechanism, the influence of acidity on the reaction rate constant was investigated. When the acidity of the system is increased, retardation of urethane formation occurs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2322–2329, 2002     

Thermal and Mechanical Properties of Poly(arylene ether ketone)s Based on 5‐tert‐Butyl‐1,3‐bis(4‐fluorobenzoyl)benzene

An aromatic bishalide, 5‐tert‐butyl‐1,3‐bis(4‐fluorobenzoyl)benzene ( 2 ) was synthesized in high yield and purity by the reaction of 5‐tert‐butylisophthaloyl chloride ( 1 ) and fluorobenzene and polymerized by nucleophilic substitution reaction with commercially available aromatic bisphenols to prepare a series of high molecular weight poly(arylene ether ketone)s containing pendant tertiary butyl groups. The effect of molecular structure on the physical, thermal, mechanical and adhesion properties of the polymers was investigated.     

Superbase‐Catalyzed [4+2] Cycloaddition of Acetylenes to 3,6‐Di(pyrrol‐2‐yl)‐1,2,4,5‐tetrazine: A Facile Synthesis of 3,6‐Di(pyrrol‐2‐yl)pyridazines

Acetylenes undergo the [4+2] cycloaddition to 3,6‐di(pyrrol‐2‐yl)‐1,2,4,5‐tetrazine in the potassium hydroxide/dimethyl sulfoxide or potassium tert‐butoxide/dimethyl sulfoxide systems (80 °C, 2.5–4 h) to afford (after extrusion of the nitrogen molecule from the intermediate) 3,6‐di(pyrrol‐2‐yl)pyridazines in up to 73% yield, while under non‐catalytic conditions this reaction does not take place. This unusual result substantially extends the scope of synthetic application and mechanistic diversity of the Diels–Alder reaction. The step‐wise mechanisms involving the formation of [OH/tetrazine]⁻ or [t‐BuO/tetrazine]⁻ anionic intermediate complexes or cycloaddition of tetrazine to the acetylide anion are considered.     

Polyethylene‐b‐poly(ethylene glycol) diblock copolymers: New synthetic strategy and application

Polyethylene‐b‐poly (ethylene glycol) (PE‐b‐PEG) was successfully synthesized by a coupling reaction of hydroxyl‐terminated polyethylene (PE‐OH) and isocyanate‐terminated poly (ethylene glycol) (PEG‐NCO). PE‐OH was prepared by coordination chain transfer polymerization (CCTP) using 2,6‐bis[1‐(2,6‐diisopropylphenyl)imino ethyl] pyridine iron (II) dichloride /dry ethylaluminoxane (DEAO) /diethyl zinc (ZnEt₂) as catalyst and subsequent in situ oxidation with oxygen. The active centers of this catalyst system were counted, indicating that the active centers were more stable using DEAO as cocatalyst than using dry methylaluminoxane (DMAO) as cocatalyst. PEG‐NCO was synthesized through the condensation reaction of monomethylpoly(ethylene glycol) (PEG) with isophoronediisocyanate (IPDI). Subsequently, the thermal characterization, morphological characterization and the application of these diblock copolymers was investigated. The results indicated that the diblock copolymers were effective compatilizers for polyethylene/poly(ethylene glycol) blends. Meanwhile, they were excellent surface modification agents for polyethylene membrane and glass sheet, it can efficiently turn a hydrophobic surface into a hydrophilic surface, or vice versa. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42236.     

Synthesis of novel azo‐containing polyureas derived from 4‐[4′‐(2‐hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione

4‐[4′‐(2‐Hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione ( HNAPTD ) ( 1 ) has been reacted with excess amount of n‐propylisocyanate in DMF (N,N‐dimethylformamide) solution at room temperature. The reaction proceeded with high yield, and involved reaction of both N? H of the urazole group. The resulting bis‐urea derivative 2 was characterized by IR, ¹H‐NMR, elemental analysis, UV‐Vis spectra, and it was finally used as a model compound for the polymerization reaction. Solution polycondensation reactions of monomer 1 with Hexamethylene diisocyanate ( HMDI ) and isophorone diisocyanate ( IPDI ) were performed in DMF in the presence of pyridine as a catalyst and lead to the formation of novel aliphatic azo‐containing polyurea dyes, which are soluble in polar solvents. The polymerization reaction with tolylene‐2,4‐diisocyanate ( TDI ) gave novel aromatic polyurea dye, which is insoluble in most organic solvents. These novel polyureas have inherent viscosities in a range of 0.15–0.22 g dL^?1 in DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3177–3183, 2001     

Influence of DMF on the polymerization of tert‐butyl acrylate initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator

BACKGROUND: In a number of studies it has been shown that 2,2,6,6‐tetramethylpiperidinooxy (TEMPO)‐mediated polymerization of acrylates is not facile. Therefore, the object of the study reported here was to prepare poly[styrene‐block‐(tert‐butyl acrylate)] (PS‐b‐PtBA) block copolymers using 4‐oxo‐TEMPO‐capped polystyrene macroinitiator as an initiator, in the presence of small amounts of N,N‐dimethylformamide (DMF). The kinetic analysis and the effect of DMF on the reaction mechanism are also discussed. RESULTS: PS‐b‐PtBA block copolymer was prepared through polymerization of tert‐butyl acrylate (tBA) initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator at 135 °C. The polymerization rate of tBA could be increased by adding a small amount of DMF, and the number average molecular weight of the PtBA block in PS‐b‐PtBA reached 10 000 g mol^?1 with narrow polydispersity. The activation rate constant k_act?tBA of alkoxyamine increased and the recombination rate constant k_rec?tBA decreased with increasing DMF concentration. CONCLUSION: DMF was shown to be a rate‐enhancing additive for the polymerization of tBA using a 4‐oxo‐TEMPO‐capped polystyrene macroinitiator. From the kinetic analysis, it was concluded that the improvement of polymerization with the addition of DMF was due to an increase in k_act?tBA and a decrease in k_rec?tBA. Copyright © 2008 Society of Chemical Industry     

Synthesis and structural characterization of novel chiral nanostructured poly(esterimide)s containing different natural amino acids and 4,4′‐thiobis(2‐tert‐butyl‐5‐methylphenol) linkages

Pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) (1) was reacted with several amino acids in acetic acid and the resulting imide‐acid [N,N′‐(pyromellitoyl)‐bis‐L ‐amino acid diacid] (4a–4d) was obtained in high yield. The direct polycondensation reaction of these diacids with 4,4′‐thiobis(2‐tert‐butyl‐5‐methylphenol) (5) was carried out in a system of tosyl chloride(TsCl), pyridine, and N,N‐dimethyl formamide (DMF) to give a series of novel optically active poly(esterimide)s. Step‐growth polymerization was carried out by varying the time of heating and the molar ratio of TsCl/diacid, and the optimum conditions were achieved. These new chiral polymers were characterized with respect to chemical structure and purity by means of specific rotation experiments, FTIR, ¹H‐NMR, X‐ray diffraction, elemental, and thermogravimetric analysis (TGA) field emission scanning electron microscopy (FE‐SEM) techniques. These polymers are readily soluble in many polar organic solvents like DMF, N,N‐dimethyl acetamide, dimethyl sulfoxide, N‐methyl‐2‐pyrrolidone, and protic solvents such as sulfuric acid. TGA showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 390°C; therefore, these new chiral polymers have useful levels of thermal stability associated with good solubility. Furthermore, study of the surface morphology of the obtained polymers by FE‐SEM showed that each polymers exhibit nanostructure morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Rheo‐kinetic evaluation on the formation of urethane networks based on hydroxyl‐terminated polybutadiene

Rheo‐kinetic studies on bulk polymerization reaction between hydroxyl‐terminated polybutadiene (HTPB) and di‐isocyanates such as toluene‐di‐isocyanate (TDI), hexamethylene‐di‐isocyanate (HMDI), and isophorone‐di‐isocyanate (IPDI) were undertaken by following the buildup of viscosity of the reaction mixture during the cure reaction. Rheo‐kinetic plots were obtained by plotting ln (viscosity) vs. time. The cure reaction was found to proceed in two stages with TDI and IPDI, and in a single stage with HMDI. The rate constants for the two stages k₁ and k₂ were determined from the rheo‐kinetic plots. The rate constants in both the stages were found to increase with catalyst concentration and decrease with NCO/OH equivalent ratio (r‐value). The ratio between the rate constants, k₁/k₂ also increased with catalyst concentration and r‐value. The extent of cure reaction at the point of stage separation (x_i) increased with catalyst concentration and r‐value. Increase in temperature caused merger of stages. Arrhenus parameters for the uncatalyzed HTPB‐isocyanate reactions were evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1869–1876, 2001     

Effects of solvent polarity on the reaction of phenol with tolylene‐2,4‐diisocyanate

Using tolylene‐2,4‐diisocyanate as standard compound, the relationship between ? NCO absorbance and concentration was studied with in situ FTIR. The linear relationship appeared correct only for concentrations lower than 0.4 mol L^?1. Then, the urethane reaction kinetics of phenol with tolylene‐2,4‐diisocyanate were investigated in different solvents, such as dimethyl sulfoxide, cyclohexanone, n‐butyl acetate, 1,4‐dioxane, and xylene. It showed that solvents largely affected reaction rates. The reaction was largely accelerated in polar solvents, following the order of dimethyl sulfoxide > cyclohexanone > n‐butyl acetate > 1,4‐dioxane > xylene. It was in contrast to the alcohol–diisocyanate reaction. Finally, an appropriate reaction mechanism was proposed. The H? O bond in phenol was polarized under the influence of solvents, which made the combination of hydrogen to nitrogen and alkoxyl group to carbenium easier. After that the solvent was dissociated and the carbamate generated. The kinetic equation could be derived as v = k′K·[S:] [ROH]·[R′NCO]. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

DVD substrate application for polycarbonate end‐capped with 4‐α‐cumylphenol

Using 4‐α‐cumylphenol as the end‐capping agent, polycarbonates (PCs) with a viscosity‐average molecular weight (M_v) of 13,800 were prepared. DVD substrates were molded using these PCs. DVD substrates using PCs end‐capped with 4‐α‐cumylphenol (CP–PCs) have lower retardation than do those using conventional PCs end‐capped with 4‐tert‐butylphenol (TBP–PCs). Using CP–PC, it is possible to bring the mold temperature down about 20°C from the standard conditions of molding DVD substrates using TBP–PC at the same radial birefringence. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 404–406, 2003     

Ring‐opening polymerization of ε‐caprolactone by a new yttrium complex: Y[2,2′‐ethylidene‐bis(4,6‐di‐tert‐butylphenoxy)]2(ethylene glycol dimethyl ether)Na(ethylene glycol dimethyl ether)3

The main aims of the work reported here were to synthesize and characterize a new 2,2′‐ethylidene‐bis(4,6‐di‐tert‐butylphenol) (EDBPH₂)‐based bimetal yttrium complex, Y(EDBP)₂(DME)Na(DME)₃ (1c; where DME is ethylene glycol dimethyl ether), which was employed as an efficient initiator for the ring‐opening polymerization of ε‐caprolactone (ε‐CL). From single‐crystal X‐ray diffraction, the solid structure of this new bimetal initiator was well established. Experimental results show that 1c initiates the ring‐opening polymerization of ε‐CL to afford poly(ε‐CL) with a narrow molecular weight distribution (M_w/M_n = 1.09–1.36, 65 °C). Based on an in situ NMR study, a plausible coordination–insertion mechanism is then proposed. The bimetal complex 1c can be used as an initiator for the ring‐opening polymerization of ε‐CL with some living characteristics. A study of the mechanism reveals that DME displacement in 1c by ε‐CL is involved in the initiation process and the propagation may proceed through three pathways by Na? O insertion or Y? O insertion. Copyright © 2009 Society of Chemical Industry     

Formulation and performance evaluation of hydroxyl terminated hyperbranched polyesters based poly (ester–urethane–urea) coatings on mild steel

A low molecular weight, anticorrosive hyperbranched poly (ester–urethane–urea) [HB-P(EUU)] coatings were formulated using 2nd generation hydroxyl terminated hyperbranched polyesters (OH–HBPEs), isophorone di-isocyanate (IPDI) as a cross linking agent and dibutyltin dilaurate (DBTDL) as a catalyst with certain additives. First, NCO terminated prepolymers (HBPEUs) were formulated by reacting OH–HBPEs with IPDI at NCO:OH ratio of 1.1:1 for 4 h at 70–80 °C, then HBPEUs were mixed with DBTDL and various additives and finally coated on pretreated cold rolled mild steel (MS) substrates by dip coating method. Before applying on MS substrates, viscosity and volume solid of coatings were measured. The molecular structure of HBPEUs was characterized by ATR-FTIR and ¹H NMR analysis. Surface morphology of coated panels was characterized by atomic force microscopy (AFM) and found that coating components were homogeneously distributed and surface was smooth and crack free. Performance of coated substrates was evaluated by various tests such as cross hatch and pull off adhesion, abrasion resistance, scratch resistance, impact resistance, flexibility, and pencil hardness. UV stability of coated substrates was evaluated by UV-whether-o-meter and corrosion resistance property was evaluated by salt spray, humidity, polarization and electrochemical impedance (EIS) test. Results were also compared with polyurethane coating based on linear polyester. HB-P(EUU) coatings showed excellent enhancement in mechanical, durability as well as corrosion resistance properties than their linear counterpart.     

Synthesis,characterization, and in vitro drug release study of 3‐arm poly‐β‐alanine

Synthesis of three arms star‐shaped poly‐β‐alanine (3‐b‐ala) based on tri(prop‐2‐yn‐1‐yl) benzene‐1,3,5‐tricarboxylate (TBT) and azido terminated poly‐β‐alanine (N₃‐P‐ala) was performed using click reaction. TBT was synthesized by nucleophilic substitution reaction between propargyl alcohol and 1,3,5‐benzenetricarbonyltrichloride. For the first time, N₃‐P‐ala was synthesized through anionic polymerization of acrylamide using sodium azide as an initiator. TBT was characterized by FT‐IR and ¹HNMR. N₃‐p‐ala was characterized by FT‐IR, GPC, and ¹HNMR and 3‐b‐ala was characterized by FT‐IR, GPC, ¹HNMR, TGA, and XRD. The synthesized 3‐b‐ala was used for drug loading and releasing studies. Polymer loaded drug (3‐b‐ala‐D) hybrid was used in in vitro studies of drug (Diclofenac sodium) release in phosphate buffer solution (PBS) at 37 ± 0.5°C and pH 7.4. The drug loading and releasing studies were analyzed by UV‐visible spectrophotometer. 3‐b‐ala‐D was examined by AFM to analyze the surface morphology and roughness. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42124.     

Thermal and thermomechanical properties of hyperbranched polyurethane‐urea/cenosphere hybrids

Hyperbranched polyurethane (HBPU)‐urea/cenosphere hybrid coatings were synthesized by incorporating various concentrations of cenosphere into HB polyester matrix by ultrasonication technique, and this polyester was further used for the preparation of isocyanate terminated HBPU prepolymers by reacting with excess isophorone diisocyanate (IPDI) in a NCO/OH ratio of 1.6 : 1. The desired hybrid coating is obtained by moisture curing the excess NCO present in the prepolymer through film casting. The structure of the hyperbranched polyester (HBPE) was conformed by ¹H, ¹³C NMR and FTIR spectroscopy and the degree of branching (DB) was calculated using Frechet and Frey equations. These hybrid films were characterized by powder XRD, FTIR, SEM, DMTA, and TGA. The structure property correlation, intermolecular/intramolecular hydrogen bonding, the surface morphology, and viscoelastic properties were studied. These results showed an increase in T_g and thermal stability of the hybrid coatings than the base polymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Microwave‐assisted and classical heating polycondensation reaction of bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine with diisocyanates as a new method for preparation of optically active poly(amide imide)s

A new class of optically active poly(amide imide)s were synthesized via direct polycondensation reaction of diisocyanates with a chiral diacid monomer. The step‐growth polymerization reactions of monomer bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine (BPABTL) (5) as a diacid monomer with 4,4′‐methylene bis(4‐phenylisocyanate) (MDI) (6) was performed under microwave irradiation, solution polymerization under gradual heating and reflux condition in the presence of pyridine (Py), dibuthyltin dilurate (DBTDL), and triethylamine (TEA) as a catalyst and without a catalyst, respectively. The optimized polymerization conditions according to solvent and catalyst for each method were performed with tolylene‐2,4‐diisocyanate (TDI) (7), hexamethylene diisocyanate (HDI) (8), and isophorone diisocyanate (IPDI) (9) to produce optically active poly(amide imide)s by the diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.09–1.10 dL/g. These polymers are optically active, thermally stable, and soluble in amide type solvents. All of the above polymers were fully characterized by IR spectroscopy, ¹H NMR spectroscopy, elemental analyses, specific rotation, and thermal analyses methods. Some structural characterization and physical properties of this new optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1647–1659, 2004     

Kinetic study of polyurethane synthesis using different catalytic systems of Fe,Cu, Sn,and Cr

This work presents a comparative study between alternative catalytic systems, metal‐β‐diketones complexes (iron, copper, chromium, and tin), and the commercial catalyst dibutyltin dilaurate, DBTDL, in the polyurethanes synthesis obtained from isophorone diisocyanate (IPDI) and polyols as polypropyleneglycol/diethyleneglycol and 1,6‐hexanodiol polyadipate (polyester A‐Mn = 2000 g/mol and polyester B‐Mn = 1000 g/mol) reactions. The polyurethanes synthesis was followed by the IPDI consumption in time, verified by infrared spectroscopy (FTIR) through the decrease of free NCO characteristic band at 2300–2200 cm^?1. The FTIR data was used to determine the polyurethanes formation kinetic behavior. It was verified that for the reactions with polyethers excess, DBTDL catalyst was more effective when compared to metal‐β‐diketones complexes, while for the reactions with polyester, A and B, the metal‐β‐diketones complexes were more effective. © 2009 Wiley Periodicals, Inc. JAppl Polym Sci, 2010