Step‐growth polymerization of 5‐[(9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboximido)‐3‐methylbutanoyl‐amino]isophthalic acid with aromatic diols

cis‐9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboxylic acid anhydride ( 1 ) was converted to imide acid ( 2 ) by reaction with S‐valine. Compound 2 was converted to the acid chloride ( 3 ) by reaction with thionyl chloride and then treated with 5‐aminoisophthalic acid in dry N,N‐dimethylacetamide to obtain 5‐[(9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboximido)‐3‐methylbutanoylamino]isophthalic acid ( 4 ). Direct step‐growth polymerization of this novel chiral diacid monomer 4 with a series of different diols in a system of tosyl chloride, pyridine, and N,N‐dimethylformamide was carried out. The optically active polyesters (PEs) were obtained with good yield and moderate inherent viscosity ranging from 0.23 to 0.48 dL/g. The resulting polymers were characterized with FTIR, ¹H‐NMR, and elemental analysis techniques. The prepared PEs showed good thermal stability up to 320°C as measured by thermogravimetric analysis. Specific rotation experiments demonstrated the induction of optical activity due to successful insertion of S‐valine in the structure of pendant groups. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermodynamic hydrogen bonding inpoly(styrene‐co‐acrylic acid)/poly(styrene‐co‐4‐N,N‐dimethylacrylamide) blends

FTIR study of the hydrogen bonding interactions within blends of different ratios of poly(styrene‐co‐acrylic acid) containing 18, 27, and 32 mol% of acrylic acid (SAA) and poly(styrene‐co‐N,N‐dimethylacrylamide) containing 17 mol% of N,N‐dimethylacrylamide (SAD‐17) was carried out qualitatively and quantitatively in the temperature range varying from room temperature to 210°C. Two new bands characterizing these interactions appeared in the 1800–1550 cm^–1 region at 1730 cm^–1 and 1616 cm^–1 and are attributed to “liberated” carbonyl group of the acidic copolymer and the “associated amide” carbonyl group, respectively. Equilibrium constants describing both the self‐association K₂ and inter‐association K_A and the enthalpy of hydrogen bonding formation in the different blends were experimentally determined using a curve fitting analysis of the infra‐red spectra as a function of temperature using the appropriate equations derived from the Painter‐Coleman association model. The obtained results confirm the miscibility of these blends in the considered temperature range from the negative values of the total free energy of mixing ΔG_M. Optimization of the extent of intermolecular interactions between the two polymers in these blends is investigated. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Entrapment of urease in poly(1‐vinyl imidazole)/poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) network

In this article, urease was immobilized in a conducting network via complexation of poly(1‐vinyl imidazole) (PVI) with poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PAMPS). The preparation method for the polymer network was adjusted by using Fourier transform infrared (FTIR) spectroscopy. A scanning electron microscope (SEM) study revealed that enzyme immobilization had a strong effect on film morphology. The proton conductivity of the PVI/PAMPS network was measured via impedance spectroscopy, under humidified conditions. The basic characteristics (Michealis‐Menten constants, pH_opt, pH_stability, T_opt, T_stability, reusability, and storage stability) of the immobilized urease were determined. The obtained results showed that the PAA/PVI polymer network was suitable for enzyme immobilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of novel pH‐responsive poly(2‐hydroxylethyl methacrylate‐co‐N‐allylsuccinamic acid) hydrogels for drug delivery

In this study, N‐allylsuccinamic acid (NASA) was synthesized in a single step with a yield of 85%. Carboxylic acid containing NASA was characterized through Fourier transform infrared (FTIR) radiation and ¹H‐NMR and ¹³C‐NMR analysis, and then it was used for synthesis of poly(2‐hydroxylethyl methacrylate‐co‐N‐allylsuccinamic acid) [p(HEMA‐co‐NASA)] hydrogels. The structure of the obtained pH‐responsive p(HEMA‐co‐NASA) hydrogels were characterized with FTIR spectroscopy and scanning electron microscopy analysis, and their swelling characterization was carried out under different drug‐release conditions. In the application step of the study, the hydrogels were used for the in vitro release of vitamin B12 and Rhodamine 6G, which were selected as model drugs. We determined that the hydrogels used as a drug‐delivery matrix could release the drug they had absorbed under different release conditions (phosphate‐buffered saline, 0.9% NaCl, and pH 1.2) at high rates for time periods of up to 24 h. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39660.     

Dilute solution viscosity properties of high molar mass poly(acrylonitrile‐co‐itaconic acid)

The intrinsic viscosities [η] and viscosity constants of high molar mass poly(acrylonitrile‐co‐itaconic acid) copolymer in DMF were obtained by the methods of Huggin, Fuoss, Martin and Schulz‐Blaschke. The values of [η] by averaging procedures suggested by Sakai were close to those from Huggins method. There was an abnormal positive deviation from the rectilinearity of the reduced viscosity (η_red) versus concentration (c) plot in all the cases in the dilute regime, which was attributed to the polyelectrolytic effect. This was further confirmed by the analysis by Fuoss method. The deviation from the Huggins dependence is discussed for a good solvent (DMF) alone and in the presence of a non‐solvent, methanol. The deviation cross‐over points c′ and c″ changed with molecular weight, and the concentration range greater than c″ and less than c* was taken for a more reliable determination of intrinsic viscosity. The non‐solvent played a key role in determining the polymer–polymer interactions. The Huggins coefficient increased and the cross‐over points c′ and c″ shifted to higher concentration regime as the mixed solvent became poorer. The inter‐ and intra‐polymer interactions increased in the presence of methanol. In poor solvent, the enhanced intramolecular interactions caused the polymer to shrink in size, causing a reduction in [η] and hydrodynamic volume. Copyright © 2003 Society of Chemical Industry     

A molecularly imprinted polymer as artificial receptor for the detection of indole‐3‐carbinol

Molecularly imprinting polymer technology is used to prepare a molecularly imprinted polymer (MIP) for the selective recognition of indole‐3‐carbinol (I3C), a chemopreventive and chemotherapeutic phytochemical associated with the anticancer activities of cruciferous vegetables. Prepolymerization study via nuclear magnetic resonance technique is done to choose the best functional monomer that establishes more interaction with the template. The prepared MIP is tested before in batch experiments and subsequently used as solid‐phase extraction sorbent for the selective detection of I3C from standard solutions. In order to verify the selectivity of the MIP, the binding of structurally related compounds, such as indole‐3‐acetonitrile, teophylline, and tryptophan, on the polymer is investigated. The experiments indicate that the MIP is highly selective for I3C with an association constant of K_a = (1.37 ± 0.07) × 10³ M^?1. Standard mixture solution loaded on MIP‐SPE cartridge give a recovery of 95% for I3C, while the other compounds are totally eluted during washing step. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40819.     

Poly(2‐acrylamido glycolic acid‐co‐2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid): Synthesis,characterization, and retention properties for environmentally impacting metal ions

Poly(2‐acrylamido glycolic acid‐co‐2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) [P(AGA‐co‐APSA)] was synthesized by radical polymerization in an aqueous solution. The water‐soluble polymer, containing secondary amide, hydroxyl, carboxylic, and sulfonic acid groups, was investigated, in view of their metal‐ion‐binding properties, as a polychelatogen with the liquid‐phase polymer‐based retention technique under different experimental conditions. The investigated metal ions were Ag⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, and Cr³⁺, and these were studied at pHs 3, 5, and 7. P(AGA‐co‐APSA) showed efficient retention of all metal ions at the pHs studied, with a minimum of 60% for Co(II) at pH 3 and a maximum close to 100% at pH 7 for all metal ions. The maximum retention capacity (n metal ion/n polymer) ranged from 0.22 for Cd²⁺ to 0.34 for Ag⁺. The antibacterial activity of Ag⁺, Cu²⁺, Zn²⁺, and Cd²⁺ polymer–metal complexes was studied, and P(AGA‐co‐APSA)–Cd²⁺ presented selective antibacterial activity for Staphylococcus aureus with a minimum inhibitory concentration of 2 μg/mL. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and pH‐responsive performance of silane‐modified poly(methylacrylic acid)

The poly(methylacrylic acid) modified by silane [poly(methylacrylic acid‐co‐vinyl triethoxylsilane) (PMAA)] was prepared via free‐radical polymerization with different mass ratios of methylacrylic acid to vinyl triethoxylsilane (VTES). The swelling performance of the prepared PMAA in different solutions with various pH values, salt species (NaCl and CaCl₂), and concentrations was investigated in detail. The results indicated that the introduction of silane boosted the stability of the obtained PMAA in aqueous solutions in the presence of an increased quantity of VTES additive. Meanwhile, the different swelling ratios of PMAA in various pH solutions showed a high pH responsivity. In addition, we found that when the PMAA underwent a number of swelling–deswelling cycles, it demonstrated the good reversibility properties when the pH value of the swelling medium was changed from 9.0 to 1.4. Moreover, the swelling mechanism of PMAA in different solutions with different pH values was investigated. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40403.     

Solvent diffusion in silica/poly[styrene‐co‐(acrylic acid)] core‐shell microspheres by pulsed field gradient NMR techniques

Polymer‐coated SiO₂ particles are prepared by precipitation of poly[styrene‐co‐(acrylic acid)] on SiO₂ microspheres through an improved phase inversion method. The diffusion resistance of the polymer membrane was considered to be the critical reason for producing tailor‐made polyethylene by catalysts supported on these polymer‐coated particles. This paper employs pulsed field gradient NMR (PFG‐NMR) to distinguish diffusion of n‐hexane in different regimes, i.e., in the space between each particle, the pores in SiO₂ and the polymer shell, by their respective diffusion coefficients. By varying the observation time, the time scale of the molecular exchange is discussed. A three‐region ansatz was used to interpret the exchange and diffusion in polymer‐coated SiO₂ system, and was compared with results acquired with noncoated particles. At long diffusion times, the mean‐squared displacement, and thus the averaged self‐diffusion coefficient, of hexane in the system of polymer‐coated SiO₂ particles is significantly reduced. The PSA membrane is identified as an efficient barrier against molecular exchange between the pores in SiO₂ and the intraparticle space. Consistently, the relaxation measurements indicated that the mobility of n‐hexane molecules, especially the rotation of n‐hexane, was limited by the PSA membrane. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40160.     

Poly(acrylic acid‐co‐acrylamide‐co‐2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)‐grafted nanocellulose/poly(vinyl alcohol) composite for the in vitro gastrointestinal release of amoxicillin

Superabsorbent polymer composites (SAPCs) are very promising and versatile materials for biomedical applications. This study concentrates on the development of novel cellulose‐based SAPC, Poly(acrylic acid‐co‐acrylamide‐co?2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)‐grafted nanocellulose/poly(vinyl alcohol) composite, P(AA‐co‐AAm‐co‐AMPS)‐g‐NC/PVA, as a potential drug delivery vehicle. Amoxicillin was selected as a model drug, which is used for the treatment of Helicobacter pylori induced peptic and duodenal ulcers. P(AA‐co‐AAm‐co‐AMPS)‐g‐NC/PVA was synthesized by graft copolymerization reaction, and FTIR, XRD, SEM, and DLS analyses were performed for its characterization. Equilibrium swelling studies were conducted to evaluate the stimuli‐response behavior of the SAPC and found that equilibrium swelling was dependent on pH, contact time, temperature, ionic strength, concentration of crosslinker and PVA. Maximum drug encapsulation efficiency was found out by using different concentrations of amoxicillin. Drug release studies were carried out at simulated gastric and intestinal fluids and the release % was observed as maximum in intestinal fluids within 4 h. The drug release kinetics was investigated using Peppas' potential equation and follows non‐Fickian mechanism at pH 7.4. Thus, the drug release experiments indicate that P(AA‐co‐AAm‐co‐AMPS)‐g‐NC/PVA would be a fascinating vehicle for the in vitro administration of amoxicillin into the gastrointestinal tract. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40699.     

Synthesis,characterization and biodegradation studies of chain‐coupled polyesters based on tartaric acid

A series of chain‐coupled polyesters based on tartaric acid was synthesized and characterized following a two‐step procedure. In the first step, tartaric acid based hydroxyl terminated polyesters with various alkane diols were prepared and then, in a second step, a chain‐coupling approach using hexamethylene diisocyanate was employed on the synthesized polyesters to prepare a series of chain‐coupled polyesters. The number‐average molecular weights (M_n) of the polyesters were found to vary in the range (4.8 ? 28.1) × 10³ g mol^?1. Thermomechanical studies demonstrate that the storage modulus of the chain‐coupled polyesters decreases with increasing polymethylene chain length which is attributable to enhanced flexibility. The isolation of bacteria on medium containing polymer as the sole source of carbon indicates the ability of the synthesized polyesters to be taken up by microorganisms for growth. © 2013 Society of Chemical Industry     

Adsorption of lactic acid onto three ionic liquid‐modified porous polymers

Three ionic liquid (IL)‐modified porous polymers were synthesized and used for the adsorption of lactic acid. The experimental adsorption kinetics and equilibrium data from the IL‐modified polymers were obtained. The kinetic study revealed a low temperature to be advantageous to the adsorption process. The dependence of the level of lactic acid adsorption on the amount of polymer, initial lactic acid concentration, and pH was examined at equilibrium. The maximum efficiency was obtained using the maximum adsorbent dose. A comparison of lactic acid adsorption at different pH revealed anion exchange to be the main interaction between the lactic acid and polymers, not molecular adsorption. The amounts adsorbed were fitted to the Langmuir, Freundlich, and Temkin equations. The equilibrium data for modified polymers (imidazole modified polymer, methylimidazole modified polymer, and ethylimidazole modified polymer) were best represented by the Langmuir and Freundlich isotherm with R² values of 0.99. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis,characterization, and metal complexation of poly(N‐phenylmaleimide‐co‐acrylic acid) and poly(N‐phenylmaleimide‐co‐acrylamide) as polychelatogens in aqueous solution

We carried out the free‐radical copolymerization of N‐phenylmaleimide with acrylic acid and acrylamide with an equimolar feed monomer ratio. We carried out the synthesis of the copolymers in dioxane at 70°C with benzoyl peroxide as the initiator and a total monomer concentration of 2.5M. The copolymer compositions were obtained by elemental analysis and ¹H‐NMR spectroscopy. The hydrophilic polymers were characterized by elemental analysis, Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, and thermal analysis. Additionally, viscosimetric measurements of the copolymers were performed. Hydrophilic poly(N‐phenylmaleimide‐co‐acrylic acid) and poly(N‐phenylmaleimide‐co‐acrylamide) were used for the separation of a series of metal ions in the aqueous phase with the liquid‐phase polymer‐based retention method in the heterogeneous phase. The method is based on the retention of inorganic ions by the polymer in conjunction with membrane filtration and subsequent separation of low‐molecular‐mass species from the formed polymer/metal‐ion complex. The polymer could bind several metal ions, such as Cr(III), Co (II), Zn(II), Ni(II), Cu(II), Cd(II), and Fe(III) inorganic ions, in aqueous solution at pH values of 3, 5, and 7. The interaction of the inorganic ions with the hydrophilic polymer was determined as a function of pH and a filtration factor. Hydrophilic polymeric reagents with strong metal‐complexing properties were synthesized and used to separate those complexed from noncomplexed ions in the heterogeneous phase. The polymers exhibited a high retention capability at pH values of 5 and 7. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Computer simulation and synthesis of stimuli‐responsive polymer by sol‐gel for selective recognition of (4‐chloro‐2‐methylphenoxy)acetic acid

A novel photoresponsive functional monomer bearing a siloxane polymerizable group and azobenzene moieties was synthesized, and then photoresponsive molecularly imprinted sol‐gel polymers were successfully fabricated from the synthesized functional monomer, using (4‐chloro‐2‐methylphenoxy)acetic acid (MCPA) as a molecular template. The photoisomerization properties of the functional monomer are retained after incorporation into the rigid three‐dimensional crosslinked polymer matrix. The template is then removed from the resulting polymer to generate pores, which are complementary to the template in shape, size and functionality. The substrate affinity of the molecularly imprinted polymer (MIP) receptor sites is photoswitchable. This can be attributed to the photoisomerization of azobenzene chromophores within the MIP receptors, resulting in alteration of their geometry and the spatial arrangement of their binding functionalities. The binding affinity of the imprinted recognition sites was switchable by alternate irradiation with UV and visible light, suggesting that azobenzene groups located inside the binding sites could be used as chemical sensors and the trans–cis isomerization could regulate the affinity for MCPA. To study the hydrogen bond interactions between template molecules and functional monomer, computational molecular modeling was employed. The data indicate that the design of the MIP is rational. Copyright © 2012 Society of Chemical Industry     

Hydrogen‐bonding interactions between poly(styrene‐co‐methacrylic acid) and poly(styrene‐co‐4‐vinylpyridine)

The complexation behavior between poly(styrene‐co‐methacrylic acid) of different compositions (SMA‐12 or SMA‐29) and poly(styrene‐co‐4‐vinylpyridine) (S4VP‐6 or S4VP‐15) was studied by viscometry and differential scanning calorimetry using tetrahydrofuran (THF) and butan‐2‐one as solvents. This complexation is attributed to the presence of strong intermolecular interactions between the different polymer chains by hydrogen bonding. A single glass‐transition temperature, intermediate between those of the two pure copolymers SMA‐29 and S4VP‐15, was obtained with each composition of the mixture when THF or butan‐2‐one is used as a common solvent. The obtained results showed that the formation of such complexes depends strongly on the nature of the solvent and the contents of the interacting species. The complex formation is inhibited in THF because of the important ability of this latter to interact with the SMA. A quantitative analysis of the interactions between the constituents of these blends was carried out by FTIR spectroscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 806–811, 2005     

Electrical actuation of electroresponsive hydrogels based on poly(acrylamide‐co‐acrylic acid)/graphite suitable for biomedical applications

A pH‐sensitive composite hydrogel based on poly(acrylamide‐co‐acrylic acid)/graphite was prepared by solution polymerization process in presence of redox initiator potassium persulfate/N,N,N′,N′‐tetramethylethylenediamine and cross‐linker (ethylene glycol dimethylacrylate). The structures of the hydrogels were confirmed using Fourier transform infrared, X‐ray diffraction, and scanning electron microscopy (SEM) study. Tensile strengths of the hydrogels were determined by using a universal tensile machine, whereas the electrical conductivities of the hydrogels were evaluated using Four‐probe method. The influence of cross‐linker, graphite content, and temperature on the conductivity of the hydrogel was also investigated. The bending behavior of the conducting hydrogels was investigated by exposing the hydrogels under electric field in aqueous medium. By studying the swelling ratio of the polymer synthesized under different conditions, optimization conditions were found for a polymer with the highest swelling ratio. Also, the hemolytic potentiality test revealed that prepared hydrogels are biocompatible in nature. POLYM. COMPOS., 35:27–36, 2014. © 2013 Society of Plastics Engineers     

Polyaniline salts as polymer‐based solid acid catalyst for low molecular weight poly(lactic acid)

Polymer‐based solid acid catalyst, polyaniline (PANI) salt, is used for the first time to synthesize polymer. In continuation of our work to synthesize organic chemicals using PANI‐based solid acid catalyst, in this work, polylactic acid is synthesized by the condensation polymerization of lactic acid using PANI salts. PANI salts are characterized by FTIR, FE‐SEM, and TGA analyses. Polymerization of lactic acid in xylene solvent at 140°C for 24 h with the use of very low amount of PANI catalysts gave polylactic acid (PLLA) in the order: PANI‐MSA (46%) > PANI‐TFA (33%) > PANI‐Bi(OTf)₃ (27%) > PANI‐Cu(OTf)₂ (20%) > PANI‐Yb(OTf)₃ (15%). Molecular weights of PLLA synthesized using PANI‐MSA and PANI‐TFA are found to be 4385 and 4830, respectively. This methodology gives highly crystalline polymer with mushroom cap‐like morphology. Advantage of this methodology is the use of easily synthesizable, recyclable, easily handlable, cheaper, and eco‐friendly nature of the catalyst. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41147.     

Synthesis,characterization, and application of amberlite XAD‐2‐ salicylic acid‐ iminodiacetic acid for lead removal from human plasma and environmental samples

A new chelating resin is prepared by coup‐ling Amberlite XAD‐2 with salicylic acid (SAL) through an azo spacer. Then the polymer support was coupled with iminodiacetic acid (IDA). The resulting sorbent has been characterized by FT‐IR, elemental analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) and studied for the preconcentration and determination of trace Pb (II) ion from human biological fluid and environmental water samples. The optimum pH value for sorption of the metal ion was 5. The sorption capacity of functionalized resin is 67 mg g⁻¹. The chelating sorbent can be reused for 20 cycles of sorption–desorption without any significant change in sorption capacity. A recovery of 95% was obtained for the metal ion with 0.5M nitric acid as eluting agent. The profile of lead uptake on this sorbent reflects good accessibility of the chelating sites in the Amberlite XAD‐2‐SAL/IDA. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Pb (II) on modified resin were analyzed by Langmuir, Freundlich, Temkin, and Redlich‐Peterson models. Based on equili‐brium adsorption data the Langmuir, Freundlich, and Temkin constants were determined 0.428, 20.99, and 7 × 10⁻¹² at pH 5 and 20°C. The method was successfully applied for determination of lead ions in human plasma and sea water sample. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Poly(acrylic acid‐co‐vinylsulfonic acid): Synthesis,characterization, and properties as polychelatogen

The synthesis of the water‐soluble poly(acrylic acid‐co‐vinylsulfonic acid) at different feed monomer ratios, while maintaining constant the total number of mol, was carried out by radical polymerization. The copolymers were characterized by FTIR and ¹H‐NMR spectroscopies. The copolymer composition was determined by its sulfur content and by potentiometric titration. The metal ion binding properties for Ni(II) and Cu(II) in the aqueous phase were studied using the liquid‐phase polymer‐based retention (LPR) technique for two values of ionic strength. For comparison, the retention properties of both homopolymers were included. The complexing ability of the polymer was determined by the relative amount of carboxylic acid groups. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1698–1704, 2003     

Blends of poly(ε‐caprolactone‐b‐lactic acid) and poly(lactic acid) for hot‐melt applications

The condensation reaction product of poly(lactic acid) (PLA) and a hydroxyl‐terminated four‐armed poly(ε‐caprolactone) (PCL) was studied by size‐exclusion chromatography, DSC, and NMR. The use of both L ‐lactic acid (LLA) and rac‐lactic acid (rac‐LA) was studied and the use of two different catalysts, stannous 2‐ethylhexanoate [Sn(Oct)₂] and ferrous acetate [Fe(OAc)₂], was also investigated. The thermal stability and adhesive properties were also measured for the different formulations. The characterization results suggested the formation of a blend of PLA and a block‐copolyester of PLA and PCL. The results further indicated partial miscibility in the amorphous phase of the blend showing only one glass‐transition temperature in most cases, although no randomized structures could be detected in the block‐copolymers. The polymerization in the Fe(OAc)₂‐catalyzed experiments proceeded slower than in the Sn(Oct)₂‐catalyzed experiments. The discoloring of the polymer was minor when Fe(OAc)₂ was used as catalyst, but significant when Sn(Oct)₂ was used. The ferrous catalyst also caused a slower thermal degradation. Differences in the morphology and in the adhesive properties could be related to the stereochemistry of the poly(lactic acid). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 196–204, 2004