Fabrication and properties of solution‐cast polyaniline/carboxymethylchitin blend films

Blend films consisting of polyaniline in emeraldine base form (PANI EB) dispersed in partially cross‐linked carboxymethylchitin (CM‐chitin) were prepared by solution casting, and characterized for their physical, thermal, and electrical properties. Homogeneous and mechanically robust blend films were obtained having PANI EB contents up to 50 wt % in the CM‐chitin matrix. FTIR spectra confirm intimate mixing of the two blend components. The thermal stability of the blend films increased with increase of PANI EB content, suggesting the formation of an intermolecular interaction, such as hydrogen bonding, between PANI EB and CM‐chitin chains. The addition of PANI EB into the pure CM‐chitin film resulted in a decrease in electrical conductivity of the films owing to disruption of ionic conduction of the CM‐chitin structure. After doping the blend films by immersion in HCl solution, the electrical conductivity of the HCl‐doped films increased with increase of the PANI EB content to a maximum value of the order of 10^?3 S/cm at 50 wt % PANI EB content. The electrical conductivity of the blend films was also dependent on the HCl concentration as well as on the type of acid dopant. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Polymer blends of PBT and PP compatibilized by ethylene-co-glycidyl methacrylate copolymers

The ethylene-co-glycidyl methacrylate (EG) copolymer is an efficient reactive compatibilizer for polymer blends of poly(butylene terephthalate) (PBT) and polypropylene (PP). During melt processing, the epoxy functional group of the EG copolymer can react with the PBT carboxylic acid and/or hydroxyl terminal groups at the interface to form various EG-g-PBT copolymers. These in situ formed grafted copolymers tend to concentrate along the interface to reduce the interfacial tension at the melt and result in finer phase domains. Higher glycidyl methacrylate (GMA) content in the EG copolymer or a higher quantity of the EG compatibilizer in the blend results in a better compatibilized blend in terms of finer phase domains, higher viscosity, and better mechanical properties. The presence of only 50 ppm catalyst (ethyltriphenyl phosphonium bromide) in the EG compatibilized blend further improves the blend compatibility substantially. © 1996 John Wiley & Sons, Inc.     

A novel approach for albumin determination in aqueous media by using temperature‐ and pH‐sensitive N‐isopropylacrylamide‐co‐N‐[3‐(dimethylamino)‐propyl]methacrylamide random copolymers

Random copolymers of N‐isopropylacrylamide (NIPA) and N‐[3‐(dimethylamino)propyl]methacrylamide (DMAPM) were synthesized by solution polymerization using azobisizobutyronitrile as the initiator in 1,4‐dioxane at 60°C. NIPA‐co‐DMAPM copolymer exhibited both temperature and pH sensitivity. Thermally reversible phase transitions were observed both in the acidic and the alkaline pH regions for copolymers produced with different DMAPM/NIPA feed ratios. The pH dependency of the lower critical solution temperature (LCST) was stronger for copolymers produced with higher DMAPM feed concentrations. NIPA‐co‐DMAPM random copolymer was also sensitive to the albumin concentration. In the presence of albumin, thermally irreversible phase transitions were observed in slightly acidic and neutral media. However, reversible transitions were obtained in aqueous media containing albumin at basic pH. The phase‐transition temperature of NIPA‐co‐DMAPM copolymer significantly decreased with increasing albumin concentration at both acidic and alkaline pH values. This behavior was explained by albumin binding onto the copolymer chains by means of H‐bond formation between the dimethylamino groups of the copolymer and the carboxyl groups of albumin. For a certain range of albumin concentration, the phase‐transition temperature exhibited a linear decrease with increasing albumin concentration. By utilizing this behavior, a simple albumin assay was developed. The results indicated that NIPA‐co‐DMAPM copolymer could be utilized as a new reagent for the determination of albumin concentration in the aqueous medium. The proposed method was valid for the albumin concentration range of 0–4000 μg/mL. The protein concentrations commonly utilized in biotechnological studies fall in the range of the proposed method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2060–2071, 2002; DOI 10.1002/app.10503     

Synthesis,characterization, and antitumor activity of poly(maleic anhydride‐co‐vinyl acetate‐co‐acrylic acid)

The ternary copolymerization of maleic anhydride (MA), vinyl acetate (VA), and acrylic acid (AA) [P(MA‐co‐VA‐co‐AA)], which is considered to be an acceptor–donor–acceptor system, was carried out in 1,4‐dioxane with benzoyl peroxide as an initiator at 70°C under a nitrogen atmosphere. Constants of complex formation for the monomer systems in the study were determined by UV–visible (hydrogen‐bonding complex) and ¹H‐NMR (charge transfer complex) methods, respectively. The results show that polymerization of the P(MA‐co‐VA‐co‐AA) system proceeds by an alternating terpolymerization mechanism. It is shown that the synthesized copolymers have typical polyelectrolyte behavior, ability for reversible hydrolysis–anhydrization reactions, and semicrystalline structures. In these cases, including radical polymerization, and formation of semicrystalline structures, the hydrogen‐bonding effect plays a significant role. The in vitro cytotoxicities of the synthesized terpolymer and alternating copolymer were evaluated using Raji cells (human Burkitt lymphoma cell line). The antitumor activities of prepared anion‐active copolymers were studied using methyl–thiazol–tetrazolium colorimetric assay and 50% of the cytotoxic dose of each copolymer and terpolymer were calculated. Hydrolyzed P(MA‐co‐VA‐co‐AA) and P(MA‐alt‐AA) copolymers have sufficiently high antitumor activity, which depends on the amount of hydrogen‐bonding carboxylic groups and their regular distribution in the side chain of functional macromolecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3425–3432, 2006     

Surface modification of linear low‐density polyethylene film by amphiphilic graft copolymers based on poly(higher α‐olefin)‐graft‐poly(ethylene glycol)

In this article, a series of amphiphilic graft copolymers, namely poly(higher α‐olefin‐co‐para‐methylstyrene)‐graft‐poly(ethylene glycol), and poly(higher α‐olefin‐co‐acrylic acid)‐graft‐poly(ethylene glycol) was used as modifying agent to increase the wettability of the surface of linear low‐density polyethylene (LLDPE) film. The wettability of the surface of LLDPE film could be increased effectively by spin coating of the amphiphilic graft copolymers onto the surface of LLDPE film. The higher the content of poly(ethylene glycol) (PEG) segments, the lower the water contact angle was. The water contact angle of modified LLDPE films was reduced as low as 25°. However, the adhesion between the amphiphilic graft copolymer and LLDPE film was poor. To solve this problem, the modified LLDPE films coated by the amphiphilic graft copolymers were annealed at 110° for 12 h. During the period of annealing, heating made polymer chain move and rearrange quickly. When the film was cooled down, the alkyl group of higher α‐olefin units and LLDPE began to entangle and crystallize. Driven by crystallization, the PEG segments rearranged and enriched in the interface between the amphiphilic graft copolymer and air. By this surface modification method, the amphiphilic graft copolymer was fixed on the surface of LLDPE film. And the water contact angle was further reduced as low as 14.8°. The experimental results of this article demonstrate the potential pathway to provide an effective and durable anti‐fog LLDPE film. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Moisture-activated,electrically conducting bioadhesive hydrogels as interfaces for bioelectrodes: Effect of formulation factors on cutaneous adherence in wet environments

The effect of varying the composition of a polymer blend containing poly(methylvinyl ether-maleic anhydride) copolymer on the Brookfield viscosity of the blend and on the in vitro bioadhesive forces of resultant cast films was assessed. An increase in copolymer concentration increased both blend viscosity and film bioadhesion. Increasing the plasticizer concentration did not significantly alter bioadhesion but did influence film flexibility. Blend pH affected both viscosity and bioadhesion. However, for films to be biocompatible, formulation within the skin pH range was desirable. Films exhibited the ability to ‘restick’ after initial adherence, allowing repositioning of the adhered film in vivo. Factorial design experiments (2²) showed that an additive bioadhesive effect occurred when copolymer and PVP concentrations were increased in the polymer blend. However, no interaction between copolymer and plasticizer was observed. Addition of sodium chloride to the polymer blend, necessary to render films electrically conducting for use as bioelectrode interfaces, decreased blend viscosity but did not exert a significant effect on film bioadhesion. © 1995 John Wiley & Sons, Inc.     

Synthesis and chiroptical properties of liquid crystalline copolymers containing azobenzene chromophores

A series of new liquid crystalline copolymers, poly[((S)‐2‐methyl‐1‐butyl methacrylate)‐co‐(6‐(4‐(4‐cyanophenylazo)phenoxy)hexyl methacrylate)], with different contents of chiral units of 17, 36, 54 and 78 mol% were synthesized. The structures and properties of the copolymers were characterized and evaluated using infrared, ¹H NMR and UV spectroscopy, differential scanning calorimetry, gel permeation chromatography and circular dichroism (CD). The CD results suggested that absorptions of azobenzene chromophores were observed in films of copolymer containing 17, 36 or 54 mol% chiral units, but not in the film of copolymer containing 78 mol% chiral units. Also, CD values of the copolymeric films decreased with increasing chiral content. After irradiation with linear polarized light at 442 nm, CD values were changed in all the copolymeric films, and the CD values increased with decreasing chiral content in a nonlinear way, while the photoinduced change of chirality of the copolymers increased in a linear way with decreasing chiral content. The results are discussed in terms of interactions between structures and chiroptical properties. Copyright © 2007 Society of Chemical Industry     

Mechanical properties of latex blends films from polystyrene particles with different sizes in a butyl acrylate‐co‐styrene copolymer matrix

Blends of polystyrene (PSt) hard particle latex with three different particle sizes (96, 72, and 61 nm) and a n‐butyl acrylate‐co‐styrene (BA‐co‐St) copolymer soft latex with a 204 nm particle size were synthesized by emulsion polymerization. Latexes were standardized at 25% solids and blended at different concentrations by wt% of PSt:BA‐co‐St for every hard particle size. Finally, films from each blend were obtained. Morphology of each film prepared was examined by transmission electron microscopy, and it was found that the hard particles are randomly distributed in the films inside the copolymer matrix. The effect on mechanical properties of different PSt concentrations and particle sizes was assessed by DMA as a function of temperature. The results indicate that rigidity of the blended latex increases as the particle size diminishes as determined by the reduction in damping in the tan δ peak. The storage modulus increases as the concentration of PSt increases in the blends and the values depend upon the size of PSt particles. Mechanical properties at tension indicate that decreasing the size of the PSt particles and increasing their concentration increase the Young's modulus and ultimate strength at tension because of an increase in the rigidity of the films. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Fabrication of super water repellent silver flake/copolymer blend films and their potential as smart fabrics

A facile technique is demonstrated for the fabrication of super water repellent co‐polymer blend‐silver composite films from fatty acid surface functionalized fine silver flakes. Initially, high concentrations of surface functionalized silver flakes were dispersed in poly(vinyl chloride‐co‐vinyl acetate‐co‐vinyl alcohol) copolymer in solution to form electrically conducting adhesives/paints (ECAs) with a bulk resistivity of ∼3 × 10⁻⁵ Ω cm. The solvent‐borne ECAs were then blended with a water‐dispersed perfluoromethacrylate copolymer (Zonyl 8740) using a simple solvent‐inversion process to obtain super water‐repellent colloidal copolymer blend‐silver emulsions. The colloidal emulsions could be spray‐deposited on a number of fibrous substrates including fabrics and paper. A particular example is demonstrated herein by spray‐depositing these emulsions onto molten paraffin wax‐based laminates (60°C), which were partially impregnated into fabrics to fabricate highly water repellent, flexible, and thermoresponsive fabrics. A paraffin wax/polyolefin blend base film was used for the purpose. The surface topology of the superhydrophobic copolymer/silver composite films displayed fractal‐like hierarchical structures ideal for self‐cleaning hydrophobicity. On relatively low‐absorbent permeable porous surfaces such as cellulosic films (paper) impregnated with wax/polyolefin films, self‐cleaning ability of the coatings was maintained even for temperatures at which paraffin wax component of the laminated film was molten indicated by low‐water roll‐off angles. Hence, the composites have excellent compatibility with organic phase change materials such as paraffin wax and wax/polyolefin blends, and they can be used to fabricate nonwetting, thermoregulated, and electroactive fabrics. Antimicrobial properties of silver offer additional advantages for potential biomedical applications. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Properties of modified poly(vinyl alcohol) membranes prepared by the grafting of new polyelectrolyte copolymers for water–ethanol mixture separation

For the preparation of a water‐selective membrane for the pervaporation separation of an azeotropic solution, a series of grafted copolymers were synthesized by the reaction of poly(vinyl alcohol) (PVA) with poly(sodium salt styrene sulfonic acid‐co‐maleic acid) (PSStSA‐co‐MA). The esterification was performed between the hydroxyl groups of PVA and the carboxylic groups of the copolymer with a heat treatment. PSStSA‐co‐MA was prepared with sodium salt styrene sulfonic acid and maleic anhydride copolymerization in dimethyl sulfoxide with azobisisobutyronitrile as an initiator. The reaction mechanism and resultant structure were confirmed with IR spectra. The effect of the heat‐treatment time on the gel content was investigated. The permeation flux decreased and the separation factor increased as the crosslinking agent content rose. A membrane containing 15 wt % PSStSA‐co‐MA was used for water–ethanol azeotropic solution pervaporation at 30°C, and a flux of 0.43 kg/m² h and a separation factor of 190 were obtained. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2854–2859, 2002     

Preparation and characterization of acrylonitrile‐ethyl methacrylate copolymers and the effect of LiClO4 salt on electrical properties of copolymer films

Copolymers of poly(acrylonitrile‐co‐ethyl methacrylate), P(AN‐EMA), with three different EMA content and parent homopolymers were synthesized by emulsion polymerization. The chemical composition of copolymers were identified by FTIR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The thermal properties of copolymers were modified by changing the EMA content in copolymer compositions. Various amounts of LiClO₄ salt loaded (PAN‐co‐PEMA) copolymer films were prepared by solution casting. The dielectric properties of these films at different temperatures and frequencies were investigated. It was found that the dielectric constant and ac‐conductivity of copolymer films were strongly influenced by the salt amounts and EMA content in copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effects of tetramethylpolycarbonate‐block‐poly(styrene‐co‐acrylonitrile) copolymers containing various amounts of acrylonitrile on the interfacial properties of polycarbonate and poly(styrene‐co‐acrylonitrile) blends

Tetramethylpolycarbonate‐block‐poly(styrene‐co‐acrylonitrile) (TMPC‐block‐SAN) block copolymers containing various amounts of acrylonitrile (AN) were examined as compatibilizers for blends of polycarbonate (PC) with poly(styrene‐co‐acrylonitrile) (SAN) copolymers. To explore the effects of block copolymers on the compatibility of PC/SAN blends, the average diameter of the dispersed particles in the blend was measured with an image analyzer, and the interfacial properties of the blends were analyzed with an imbedded fibre retraction technique and an asymmetric double‐cantilever beam fracture test. Reduction in the average diameter of dispersed particles and effective improvement in the interfacial properties was observed by adding TMPC‐block‐SAN copolymers as compatibilizer of PC/SAN blend. TMPC‐block‐SAN copolymer was effective as a compatibilizer when the difference in the AN content of SAN copolymer and that of SAN block in TMPC‐block‐SAN copolymer was less than about 10 wt%. Copyright © 2004 Society of Chemical Industry     

Novel hydrogels based on itaconic acid and citraconic acid: Synthesis,metal ion binding,and swelling behavior

Several copolymer hydrogels were prepared from radical copolymerization of 2‐hydroxypropyl methacrylate (HPMA) with itaconic acid (IA) and also with citraconic acid (CA) by using different feed ratios. The copolymers were characterized by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy as well as by thermal analysis. The swelling process of the different hydrogels immersed in water at different pH has been studied, and also the swelling of the hydrogels loaded with metal ions (Pb²⁺, Cd²⁺) was investigated. The metal‐binding properties were studied by using the liquid‐phase polymer‐based retention technique, including studies on the influence of pH on the binding process. The efficiency of these hydrogels for the recovery of metal ions in solution was determined by atomic absorption spectroscopic analysis. The thermal characteristics of these copolymers were studied by using differential scanning calorimetry and thermogravimetric analysis in nitrogen atmosphere. Accordingly, the gels loaded with metal ions showed a slight increase of the thermal decomposition temperature when compared with the pristine gels. The copolymer gel HPMA‐co‐CA showed a single glass transition temperature, whereas for the copolymer systems, HPMA‐co‐IA, only the copolymers loaded with Cd²⁺ ions showed a glass transition temperature. The morphology of film produced from the copolymers was investigated by scanning electron microscopy, revealing generally smooth surfaces. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of intermolecular and intramolecular forces on hydrodynamic diameters of poly(N‐isopropylacrylamide) copolymers in aqueous solutions

A novel copolymer, poly(N‐isopropylacrylamide‐co‐hydroxypropyl methacrylate‐co‐3‐trimethoxysilypropyl methacrylate) has been synthesized and the hydrodynamic diameters in various aqueous solutions under different temperatures are determined by dynamic light scattering. The results show that the hydrodynamic diameters of copolymers have no obvious change in each working solution below lower critical solution temperature (LCST); across LCST, the diameters increased suddenly at different initial temperature in various aqueous solutions; above LCST, they decreased slightly as the temperature increased in UHQ water, and increased continuously with increasing temperature or salt concentration in saline solutions, and reduced with the rising of pH value in pH buffer. These are attributed to different intermolecular and intramolecular forces leading to disparity in dimension, conformation, and LCST of copolymers. The hydrogen bonding between water molecules and copolymer chains could maintain size and conformation of copolymer single chain; the hydrogen bonding between amide linkages and hydrophobic interactions between isopropyl groups result in intramolecular collapse and intermolecular aggregation; the electrostatic repulsion weakens aggregation extent of copolymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

In situ fibre‐reinforced composite films of poly(lactic acid)/low‐density polyethylene blends: effects of composition on morphology,transport and mechanical properties

This study aimed to investigate the effects of blend composition on packaging‐related properties of poly(lactic acid) (PLA) and low density polyethylene (LDPE) blown films. Blend films with PLA contents of 5–20 wt% were produced and compared. Scanning electron micrographs of cross‐sectional cryofractured surfaces of the blend films revealed that in situ fibre‐reinforced composites were obtained. Viscosity ratio of the polymer components of ca 1 confirmed that fibre formation was favourable for this blend system. PLA microdomains were dispersed throughout the film in forms of long fibres (length‐to‐diameter ratio > 100) and ribbons. The number of fibres and ribbons increased with an increase of PLA content. Critical content of PLA was found to be 20 wt% for effective improvement of both moduli and gas barrier properties. Incorporation of poly[ethylene‐co‐(methyl acrylate)] compatibilizer showed minimal effect on PLA structure. However, it did improve moduli and O₂ barrier properties when sufficient amount (1.5 pph) was used in 10 wt% PLA/LDPE. In short, flow behaviour, ratio of polymer components and degree of compatibility together played intricate roles in the morphology and hence mechanical and transport properties of PLA/LDPE immiscible blends. © 2017 Society of Chemical Industry     

Synthesis,viscosity behavior,and interactions with a surfactant of some amphiphilic copolymers of diallyldimethylammonium chloride and diallyldodecyl‐ or diallyloctadecyl‐ammonium chloride

The compatibilization of an immiscible polymer system polystyrene/poly(4-vinylpyridine) has been induced by the introduction of carboxylic acid groups within the polystyrene chains. Poly(styrene-co-cinnamic acid), PSCA, copolymers were used to prepare blends and complexes with poly(4-vinylpyridine), P4VP, and in a second time with poly(styrene-co-4-vinylpyridine), PS4VP, copolymer in order to reduce the density of the interacting groups. The miscibility of the systems has been ascertained by DSC, which revealed that both blends and complexes exhibit a single glass transition temperature indicating their single phase nature. The T_gs of the complexes of PS4VP with PSCA15, containing 15 mol % of cinnamic acid content, were higher than those of the corresponding blends indicating that stronger interpolymer interactions were developed in the complexes. Furthermore, the application of the Kwei equation suggested that P4VP interacts more strongly with PSCA15 than does PS4VP. FTIR spectra revealed the development of hydrogen bonding within the PS4VP/PSCA system and both hydrogen bonding and ionic interaction in the P4VP/PSCA blends whereas the same interactions were expected in both systems. This observation confirmed the stronger ability of P4VP to interact with PSCA copolymer. The viscosimetric study showed both positive and negative deviations of the reduced viscosity of the blends from the additivity law confirming the presence of specific interactions within the blend solutions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrochemical synthesis of poly(2‐iodoaniline) and poly(aniline‐co‐2‐iodoaniline) in acetonitrile

Poly(2‐iodoaniline) (PIANI) and poly(aniline‐co‐2‐iodoaniline) [P(An‐co‐2‐IAn)] were synthesized by electrochemical methods in acetonitrile solution containing tetrabutylammonium perchlorate (TBAP) and perchloric acid (HClO₄). The voltametry of the copolymer shows characteristics similar to those of conventional polyaniline (PANI), and it exhibits higher dry electrical conductivity than PIANI and lower than PANI. The observed decrease in the conductivity of the copolymer relative to PANI is attributed to the incorporation of the iodine moieties into the PANI chain. The structure and properties of these conducting films were characterized by FTIR and UV‐Vis spectroscopy and by an electrochemical method (cyclic voltametry). Conductivity values, FTIR and UV‐Vis spectra of the PIANI and copolymer were compared with those of PANI and the relative solubility of the PIANI and the copolymer powders was determined in various organic solvents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1652–1658, 2003     

Biodegradable blend films based on two polysaccharide derivatives and their use as ibuprofen‐releasing matrices

Differential scanning calorimetry (DSC), FTIR, X‐ray diffraction (XRD), and viscosity methods were used to examine the miscibility, interaction, and degradability of cationic guar gum (GG) and sodium carboxymethylcellulose (NaCMC) in their blend films. The experiment results prove that there exist electrostatic interactions and hydrogen bonding between GG and NaCMC. Blend films degrade quicker than pure GG or NaCMC film. Furthermore, the degradation rate of blend films is related to the interactions between GG and NaCMC. Based on the research of blend films as the drug carriers for Ibuprofen, it is found that the blend composition, initial drug concentration, and pH value affect the drug release and the GG/NaCMC blend films have good sustained release performance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3553–3559, 2007     

Blends of poly(vinyl butyral‐co‐vinyl alcohol) and poly(ethylene terephthalate‐co‐ethylene naphthalate): thermal,mechanical, and morphological properties

The miscibility behavior and morphology of a series of poly(vinyl butyral‐co‐vinyl alcohol) (PVBA) copolymers containing 29, 52, 76, and 88 mol % of vinyl alcohol units with poly(ethylene terephthalate‐co‐ethylene naphthalate) (PETN) was investigated by DSC and SEM. Blends of the PETN with PVBA were prepared by coprecipitation from a chloroform/o‐chlorophenol (20/80 wt %) mixture solvent. It was found that PVBAs with different vinyl alcohol content will form an immiscible phase with the amorphous PETN in the solution‐cast films. Also, PETN and PVBA with 29 mol % vinyl alcohol (PVBA‐29) are not miscible within the whole composition range. The glass‐transition temperatures of the blends were higher than those of the two‐component polymers. The values of the tensile properties of the blend films were also better than those of the original copolymer films. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2746–2751, 2001     

Morphology and hydrolysis of PCL/PLLA blends compatibilized with P(LLA‐co‐ϵCL) or P(LLA‐b‐ϵCL)

The effect of the compatibilizers, P(LLA‐co‐?CL) and P(LLA‐b‐?CL), on the morphology and hydrolysis of the blend of poly(?‐caprolactone) (PCL) and poly(L ‐lactide) (PLLA) was investigated. An addition of P(LLA‐co‐?CL) or P(LLA‐b‐?CL) into the blend could enhance the compatibility between the dispersed PCL domains and the PLLA matrix. The size of the PCL domains in the PLLA/PCL (70/30) blend containing P(LLA‐co‐?CL) reduced more significantly with an increase in the content of the compatibilizer than that in the blend containing P(LLA‐b‐?CL). The molecular weight of the PLLA/PCL blend films compatibilized with P(LLA‐co‐?CL) or P(LLA‐b‐?CL) decreased during the hydrolysis and the decrease of the molecular weight of the blend films compatibilized with P(LLA‐co‐?CL) was much more significant than that of the blend films compatibilized with P(LLA‐b‐?CL). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1892–1898, 2002