Hydrolytic Behavior Research Articles

Analysis of Selected Properties of Microporous PLA as a Result of Abiotic Degradation.

In the study, an investigation was made into the hydrolytic degradation behavior of the microporous polylactide (PLA) in the initial stage in three biological buffer solutions with various pH-simulating body fluids in comparison with pure PLA. Studies also include the analysis of selected mechanical properties and physical structures. A microporous PLA was obtained by melt extrusion using a chemical blowing agent. The rate of Mw decrease induced by hydrolysis over 35 days of microporous PLA was roughly comparable to the pure material. The rate of depolymerization was slightly accelerated at an acid pH due to acid-catalyzed hydrolysis at the end of the observed period. The mechanical analysis showed the influence of various pH on the obtained results.

Enthalpy - Entropy Compensation in the Hydrolysis of Four Tetracycline Antibiotics

An article recently published analyzed the hydrolytic transformation of four tetracycline antibiotics - tetracycline, chlortetracycline, oxytetracycline, and doxycycline - under various environmental settings and determined their parents and transformation products in the wastewater treatment plants [1]. In the article, the authors found that the hydrolytic behavior of the four tetracycline antibiotics followed first-order reaction kinetics and that the rates of the acid-catalyzed hydrolysis were significantly lower than the rates of the base-catalyzed and neutral pH hydrolysis.

Control of hydrolytic degradation of polyglycolic acid using chain extender and anti‐hydrolysis agent

AbstractBiodegradable polyglycolic acid (PGA) shows great potential to substitute engineering petrochemical‐based polymers because of its high mechanical strength, stiffness, and gas barrier. However, drawbacks such as low melt strength, poor thermal stability, and rapid degradation limited its practical applications. In this paper, PGA was modified by reactive extrusion using chain extender (CE) and anti‐hydrolysis agent (AHA). The effects of the modification on the flow properties, melt viscosity and long‐term hydrolysis behaviors of PGA were studied. Compared with the unmodified but one‐pass processed PGA (C‐PGA), the melt mass flow rate of modified PGA (M‐PGA) decreased, while the complex viscosity (ω = 0.1 rad/s) dramatically increased, attributable to the realization of effective chain extension. The accelerated hydrolysis aging test indicated that the hydrolysis rate constant of C‐PGA at 30°C was 0.06183 day−1, and that of M‐PGA was 0.01332 day−1, which exhibited a 78% reduction. Correspondingly, the service life of M‐PGA was significantly prolonged. This may expand the potential applications of PGA, such as packaging film, agriculture, or textiles.

Tuning the Hydrolytic Behavior of Hydroxyquinoline Derivatives for Anticorrosion Applications

Tuning the Hydrolytic Behavior of Hydroxyquinoline Derivatives for Anticorrosion Applications

From sucrose to fructo-oligosaccharides: Production and purification of fructo-oligosaccharides by an integrated enzymatic catalysis and membrane separation process

Fructo-oligosaccharides (FOS) are a group of linear fructose oligomers with numerous health benefits, which can be synthesized by the transfructosylation of sucrose using fructosyltransferases (FTases). In this study, it was found that the selected FTases showed both hydrolytic and transfructosylating activities. For FOS production, the hydrolytic activities of FTases became significant when the reaction time was above 1 h. Thus, FTases needed to be inactivated or removed from the reactor after achieving the highest FOS conversion. We therefore developed an integrated ultrafiltration-diafiltration- concentration process for FTases reuse and FOS purification. Because of the 100% rejection of FTases activity and a higher average flux, a PES-10 ultrafiltration membrane was selected for FTases recovery, where the cake layer formation was the main membrane fouling mechanism. Then, a fed-batch reaction process was developed for FOS production, where the hydrolytic behavior of FTases was negligible, and the FTases dosage was reduced by 75% compared to single batch operation (four batches). Moreover, the FOS production was comparable, and 95.5% FTases was recovered by the PES10 membrane after the four fed-batches processes. Subsequently, a NF5 nanofiltration membrane was selected to further separate FOS from the FTases-free FOS solution by a constant volume diafiltration process under 45 °C, and the monosaccharides in the reaction mixture (glucose and fructose) were completely removed, increasing the FOS purity from 55.8% to 92.3%. Finally, the FOS and sucrose in the diafiltration permeate was recovered by a DL nanofiltration membrane under 60 °C. The outcome of this work offers a complete technical route for FOS production using sucrose as substrate.

Sol–gel reaction of titanium phosphonate alkoxide cluster

AbstractThe synthesis and properties of titanium phosphonate cluster molecules have been investigated; however, nothing has been done to study not only the catalytic ability of a hydrolyzed cluster but also a behavior of hydrolysis–polycondensation by solvents. The sol–gel reaction of [Ti4(μ3‐O)(OiPr)5(μ‐OiPr)3(O3PPh)3]·thf (Ti4P3Ph) was performed in tetrahydrofuran (THF), toluene, and acetone. The hydrolysis–polycondensation of Ti4P3Ph proceeded in THF and toluene, while Ti4P3Ph in acetone proceeded in two paths (hydrolysis–polycondensation and nonhydrolysis–polycondensation). The hydrolyzed Ti4P3Ph retained its cluster structure, while the calcined Ti4P3Ph at 300°C contained a collapsed cluster structure. The specific surface areas of the hydrolyzed Ti4P3Ph in THF, toluene, and acetone were 154, 302, and 7 m2 g−1, respectively. The photodegradation ability of the hydrolyzed Ti4P3Ph for methylene blue was confirmed by ultraviolet irradiation at 365 nm; however, that of the calcined Ti4P3Ph was not. It was considered that the calcined Ti4P3Ph did not retain its cluster structure. The photocatalytic ability of the hydrolyzed Ti4P3Ph was high in the order of toluene > THF > pristine > acetone. The gels retained cluster structure have higher photocatalytic ability than pristine cluster; however, the gel contained a collapsed cluster structure was found no catalytic ability.

Effect of (3-aminopropyl)triethoxysilane on dissolution of silica nanoparticles synthesized via reverse micro emulsion.

Silica nanomaterials have been studied based on their potential applications in a variety of fields, including biomedicine and agriculture. A number of different molecules have been condensed onto silica nanoparticles' surfaces to present the surface chemistry needed for a given application. Among those molecules, (3-aminopropyl)triethoxysilane (APS) is one of the most commonly applied silanes used for nanoparticle surface functionalization to achieve charge reversal as well as to enable cargo loading. However, the colloidal stability of APS-functionalized silica nanoparticles has not been thoroughly studied, which can be problematic when the high reactivity of amine groups is considered. In this study, four different types of silica nanoparticles with varied location of added APS have been prepared via a reverse micro emulsion process, and their colloidal stability and dissolution behavior have been investigated. Systematic characterization has been accomplished using transmission electron microscopy (TEM), silicomolybdic acid (SMA) spectrophotometric assay, nitrogen adsorption-desorption surface area measurement, and aerosol ion mobility-mass spectrometry to track the nanoparticles' physical and chemical changes during dissolution. We find that when APS is on the interior of the silica nanoparticle, it facilitates dissolution, but when APS is condensed both on the interior and exterior, only the exterior siloxane bonds experience catalytic hydrolysis, and the interior dissolution is dramatically suppressed. The observation and analyses that silica nanoparticles show different hydrolysis behaviors dependent on the location of the functional group will be important in future design of silica nanoparticles for specific biomedical and agricultural applications.

Tuning thermal properties and biodegradability of poly(isosorbide azelate) by compositional control through copolymerization with 2,5-furandicarboxylic acid

A new fully biobased poly(isosorbide furanoate-co-azelate) (PISFAz) copolyester series was synthesized through melt polycondensation. Incorporation of 2,5-furandicarboxylic acid (FDCA), a rigid comonomer, at different molar ratios in poly(isosorbide-azelate) homopolymer led to tuning of the thermal properties and biodegradability of the resulting copolyesters. The PISFAz copolyesters with various FDCA molar content spanning from 10 to 70% were prepared and characterized by FTIR, GPC, 1D/2D NMR and viscosity measurements. It was found that PISFAz were totally amorphous materials with high thermal stability. NMR results indicated that random microstructures were obtained for the prepared copolymers with high azelaic acid content (⩾ 60 mol%). Most notably, the inclusion of FDCA units into the copolymer molecular chains induced a significant increase in the glass transition temperatures (Tg) that varied from 9.2 to 91.1 °C depending on FDCA content, leading to copolyesters with tunable Tg over a wide temperature window. The enzymatic hydrolysis behavior of PISFAz was assessed using lipases from Pseudomonas cepacia and Rhizopus oryzae revealing different susceptibility to enzymatic attack depending on the comonomer ratio, with a maximum degradation rate up to 61% after 30 days. These novel furanoate-based copolyesters show great potential to serve as promising green thermoplastic materials for applications requiring high Tg values.

Three phase purification of milk clotting protease from Wrightia tinctoria fruit and studies on its casein subunit specificity

Crude aqueous extract of Wrightia tinctoria fruit was subjected to three phase partitioning (TPP) with three different ammonium sulphate concentrations (40, 60, 80%) and their effect on concentrating milk clotting proteases were examined with 1:1 ratio of crude extract to t-Butanol. Proteases that concentrated in the interphase (IP) fraction of 60 and 80% salt concentration exhibited high milk clotting activity. TPP contributed to reduction in Caseinolytic Activity (CA) and enhancement of Milk Clotting Index (MCI) in these IP fractions compared to the crude enzyme. Casein (whole and kappa) hydrolytic pattern was analyzed by tricine SDS PAGE. Electrophoretic pattern of hydrolysate after 1 hr incubation revealed hydrolysis of κ-CN by CE, IP 60 and IP 80 fractions. Appearance of two low molecular weight bands approximately around 15 kDa indicated the specific affinity and controlled hydrolytic behavior by the proteases. Study provides evidence towards the utility of TPP in concentrating these milk clotting proteases and in improving their MCI. Keywords : Milk clotting • Wrightia tinctoria • Proteases• cheese

Sequence‐Controlled Alternating Copolyesters Synthesis via Selective Ring‐Opening Polymerization

AbstractThe hydrolysis behavior of copolyester is significantly affected by its sequence structure. The crystallinity and melting‐transition temperature of sequence‐controlled copolyesters also may be different to random copolyesters. Therefore sequence‐controlled copolyesters have become an attractive class of materials recently. Through living ring‐opening polymerization (ROP), both the molecular weight and sequence structure of copolyesters can be easily controlled. In the past decades, the development of metal‐based initiators has greatly promoted research in this field. In this minor review, the recent progress in the ROP of lactones initiated by metal complexes to synthesize copolyesters with a clear sequence structure is summarized. Moreover, the future development of sequence‐controlled copolyester synthesis will be discussed.

Enzymatic activity and stability of soybean oil body emulsions recovered under neutral and alkaline conditions: Impacts of thermal treatments

Two soybean oil body (SOB) creams were recovered from soybean at pH 7 and pH 11, respectively, and dispersed in water to obtain a natural 5% o/w emulsion. The lipoxygenase (LOX) activity and oleosin hydrolysis behavior in two SOB emulsions, as affected by different washing times and thermal treatments (50–110 °C), were investigated. The SOB emulsions recovered under neutral conditions (pH 7) were accompanied by strong enzymatic degradation. The absence of LOX and oleosin hydrolase activities was observed in SOB emulsions recovered under alkaline conditions (pH 11). The oxidative and physical stabilities of two SOB emulsions were examined at 37 °C under 15-day storage. Thermal treatment significantly enhanced the oxidative stability of two SOB emulsions due to enzymatic inactivation or altered interfacial properties. Both SOB emulsions exhibited excellent coalescence resistance after the elimination of enzymatic degradation, but their oxidative stability was different. It was due to the modification of the SOB surface by exogenous proteins that accelerated its oxidation. The results of this study might help design highly stable products based on SOB to meet the demand of people for natural products.

Identification and ecotoxicity prediction of pyrisoxazole transformation products formed in soil and water using an effective HRMS workflow

Pyrisoxazole, an isoxazoline-class fungicide, has been registered and used for approximately 19 years. However, its environmental transformation products (TPs) and corresponding ecotoxicological effects remain ambiguous. In this study, the photolysis, hydrolysis, and soil transformation behavior of pyrisoxazole were systematically investigated by indoor simulation experiments and analyzed by liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) and UNIFI software. Transformation products in different environemnts were effectively identfied by a proposed workflow, which organically combined suspect and non-target screening strategies. In total, 17 TPs were screened out. Eight TPs were confirmed using the corresponding reference standards. Structures of another 9 compounds were tentatively proposed based on diagnostic evidence. Among them, 14 products were reported for the first time. The transformation pathways of pyrisoxazole in soil and water were proposed. Pathway analysis demonstrated that the different pH of aqueous solutions had little effect on the pathways, while the influence of different soil types and oxygen conditions was evident. Finally, the toxicity of the proposed TPs to fish and daphnids was predicted using ECOSAR software. These proposed TPs in soil and water, transformation pathways, and predicted ecotoxicity information could provide systematic insight into the fate and environmental risks of pyrisoxazole.

Enzymatic kinetics of β-conglycinin using alkaline protease from Bacillus subtilis ACCC 01746 and analysis of antigenicity of hydrolyzed peptide

β-Conglycinin, the main protein of soybean, is a key allergen that causes soybean allergies, and hydrolysis is usually applied to lower its antigenicity. We evaluated the enzymolysis characters of β-conglycinin from the perspective of enzymolysis kinetics using alkaline protease from B. subtilis ACCC 01746. A dynamic model describing the hydrolysis of β-conglycinin was proposed using the initial substrate concentration, enzyme dosage (enzyme to substrate ratio) and hydrolysis time as variables to illustrate the kinetic behavior of enzymatic hydrolysis. The hydrolysis of soybean β-conglycinin was carried out at 60 g/L protein concentration, 0.6% enzyme dosage, 55 °C and pH 8.5 to observe the peptides with anti-enzymatic activities. The hydrolysates were gradually fractionated by ultrafiltration through cut-off membranes with molecular weights of 40, 30, 20, and 10 kDa, and their antigenicities were evaluated using indirect competitive enzyme-linked immunosorbent assay. The results showed that the degree of hydrolysis (DH) of β-conglycinin decreased as the β-conglycinin concentration (S0) increased, but increased with enzyme dosage (E0) increasing. Thus, the enzymatic hydrolysis of β-conglycinin followed the first-order kinetics model. The hydrolysis rate (V) was (527.89CE0–2.5533CS0) exp (–0.022DH), the DH-hydrolysis time was 45.454ln[1 + (11.614CE0/CS0–0.0562)t], and the correlated kinetic constants k2 and kd were 527.89 min−1 and 8.6126 min−1, respectively. The hydrolysis behavior of β-conglycinin varied considerably among the α', α, and β subunits. Faster hydrolysis rates were observed for the α' and α subunits compared to the β subunit. The relative molecular weights of the intercepted peptides from the hydrolysates were 14.8–40.1 kDa, and the antigenicity of the peptides with smaller molecular weight was reduced, but not removed completely. However, the alkaline protease from the strain appeared to effectively reduce the allergenicity of β-conglycinin. Therefore, it is possible to produce less allergenic soybean proteins using enzymatic hydrolysis. Additionally, the microbial alkaline protease may serve as a potential novel food enzyme and should be evaluated for the development of hypoallergenic foods.

An enzymatic membrane reactor for oligodextran production: Effects of enzyme immobilization strategies on dextranase activity

An enzymatic membrane reactor (EMR) with immobilized dextranase provides an excellent opportunity for tailoring the molecular weight (Mw) of oligodextran to significantly improve product quality. However, a highly efficient EMR for oligodextran production is still lacking and the effect of enzyme immobilization strategy on dextranase hydrolysis behavior has not been studied yet. In this work, a functional layer of polydopamine (PDA) or nanoparticles made of tannic acid (TA) and hydrolysable 3-amino-propyltriethoxysilane (APTES) was first coated on commercial membranes. Then cross-linked dextranase or non-cross-linked dextranase was loaded onto the modified membranes using incubation mode or fouling-induced mode. The fouling-induced mode was a promising enzyme immobilization strategy on the membrane surface due to its higher enzyme loading and activity. Moreover, unlike the non-cross-linked dextranase that exhibited a normal endo-hydrolysis pattern, we surprisingly found that the cross-linked dextranase loaded on the PDA modified surface exerted an exo-hydrolysis pattern, possibly due to mass transfer limitations. Such alteration of hydrolysis pattern has rarely been reported before. Based on the hydrolysis behavior of the immobilized dextranase in different EMRs, we propose potential applications for the oligodextran products. This study presents a unique perspective on the relation between the enzyme immobilization process and the immobilized enzyme hydrolysis behavior, and thus opens up a variety of possibilities for the design of a high-performance EMR.

Endonuclease IV-Regulated DNAzyme Motor for Universal Single-nucleotide Variation Discrimination.

Single-nucleotide variation (SNV) detection plays significant roles in disease diagnosis and treatment. Generally, auxiliary probe, restricted design rules, complicated detection system, and repeated experimental parameter optimization are needed to obtain satisfactory tradeoff between sensitivity and selectivity for SNV discrimination, especially when different mutant sites need to be distinguished. To overcome these limitations, we developed a universal, straightforward, and relatively cheap SNV discrimination strategy, which simultaneously possessed high sensitivity and selectivity. The excellent performance of this strategy was ascribed to the SNV discrimination property of endonuclease IV (Endo IV) and the different hydrolysis behavior between free deoxyribozyme (DNAzyme) and the trapped DNAzyme to the substrates modified on gold nanoparticles (AuNPs). When Endo IV recognized the mutant-type target (MT), free DNAzyme was released from the probe, and the DNAzyme motor was activated with the help of cofactor Mn2+ to generate an amplified fluorescence signal. On the contrary, the wild-type target (WT) could not effectively trigger the DNAzyme motor. Moreover, for different SNV types, the corresponding probe could be designed by simply changing the sequence hybridized with the target and retaining the DNAzyme sequence. Thus, the fluorescence signal generation system does not need to change for different SNV targets. Five clinical-related SNVs were determined with the limit of detection (LOD) ranging from 0.01 to 0.05%, which exhibited competitive sensitivity over existing SNV detection methods. This strategy provided another insight into the properties of Endo IV and DNAzyme, expanded the applications of DNAzyme motor, and has great potential to be used for precision medicine.

Green and sustainable carboxymethyl cellulose-chitosan composite hydrogels: Effect of crosslinker on microstructure

The toxicity level of conventional hydrogels is considerably high for most applications. To date, very few studies on hydrogels synthesized using only safe materials and simple, reproducible processes are available in the literature. Moreover, critical information on hydrogels hydrolytic behavior and stability—important parameters to determine microstructure—is missing. Herein, new composite hydrogel matrices are developed using green, sustainable materials through a simple, reproducible low-temperature chemical method. Natural polymers (carboxymethyl cellulose and chitosan), crosslinkers (fumaric acid, citric acid, tartaric acid and zinc ion), and solvent (water) are used. The hydrogels are characterized for degree of crosslinking and microstructure parameters calculated using Flory Rehner equation. Bonding strength and stability of the microstructure are further assessed. With respect to the hydrolytic properties, it was found that CMC~FU~CSN exhibits well-defined microstructure (155% swelling, 79% water absorbency and 82% gel fraction) superior to the other crosslinked hydrogels and the non-crosslinked composite, CMC~CSN. However, its gel fraction was within the same range as CMC~CSN (332% swelling, 91% water absorbency and 79% gel fraction). Other characterization results confirm that CMC~FU~CSN has the optimum microstructure (3 nm mesh size, 261 g/mol molecular weight between crosslinks and 0.01 μmol/cm3 effective crosslinking density), thermal stability (2% mass loss at 50 °C, 3% at 100 °C against 6% at 50 °C, 8% at 100 °C for CMC~CSN), semi-crystalline structure and chemical properties making it preferred over CMC~CSN as a promising green and sustainable hydrogel matrix.

Clothianidin loaded TA/Fe (III) controlled-release granules: improve pesticide bioavailability and alleviate oxidative stress

Neonicotinoid insecticides have been widely used due to their excellent systemic activity and high insecticidal activity, but the problems of low utilization rate and environmental risk have attracted widespread attention. Controlled-release technology is an approach to realize the efficient utilization of pesticides and reduce environmental pressure. In this study, clothianidin (CLO) controlled-release granules (CLO@GR- TA (tannic acid)/Fe (III)) were prepared with TA/Fe (III) coordination chelate as the coating material. These granules exhibited the core-shell structure with 500–1200 µm of particle size, and had obvious release performance and hydrolysis behavior of coating materials. Pot experiments by root application showed that the CLO@GR-TA/Fe (III) showed balanced and lasting control efficacy to broad bean aphids. The plants have a stronger capacity for absorption and enrichment and a higher utilization rate of CLO for CLO@GR-TA/Fe (III), than those for 10% suspension concentrate (SC). One of the hydrolysates of coating materials, TA, a polyphenolic antioxidant, could improve the bioaccumulation amount and alleviating the oxidative stress response of CLO in plants. Our study illustrates that the controlled-release granules base on TA have efficient controlled-release properties and free radical scavenging performance that may eventually be used as pesticide carriers and antioxidants in the field of plant protection.

Co-continuous phase prediction in poly(lactic acid) /poly(caprolactone) blends from melt viscosity measurements

ABSTRACT This paper investigates the effectiveness of a viscosity ratio model to predict phase inversion in poly(lactic acid)/poly(caprolactone) (PLA/PCL) blends. From capillary rheometry measurements, the melt viscosities of PLA and PCL were found to be 1298 and 1758 Pas respectively, at the temperature and shear strain rate of the melt blending process. Using these values, phase inversion was predicted to occur at 54 wt% of PCL. This prediction was validated both by optical microscopy and also by scanning electron microscopy (SEM) in which one of the phases had been removed by etching. For mechanical properties, the co-continuous phase morphology gave good ductility with balanced modulus and yield stress. Contact angle measurements were used to evaluate the surface energies of PLA and PCL. Experimental results of 35.5 and 44.0 mNm−1, respectively, agreed well with the values of 37.6 and 46.0 mNm−1 calculated from the Parachor method. Biodegradation tests in compost and degradation tests in phosphate buffer solution revealed that PLA and PCL hydrolyze by different mechanisms. PLA undergoes bulk degradation and brittle failure occurs after an incubation time, whereas PCL undergoes surface degradation. Prediction of phase inversion allows control of the morphology and hence the biodegradation and hydrolytic degradation behavior.

Direct observations of diffusion controlled microstructure transition in Mg-In/Mg-Ag ultrafine particles with enhanced hydrogen storage and hydrolysis properties

In this work, Mg(In) and Mg(Ag) solid-solution ultrafine particles were successfully synthesized by using a direct current (DC) arc-plasma method and their hydrogen storage and hydrolysis behaviors were thoroughly investigated. In particular, microstructural analyses clearly reveal that MgH2@MgIn and MgH2@MgAg composites are autogenerated upon hydrogenation via the formation of nano MgIn or MgAg intermetallic phase on MgH2: Mg(In/Ag) + H2 ⟷ MgH2 + MgIn/MgAg. Upon dehydrogenation, in-situ TEM observations confirm that the reverse reaction occurs through the diffusion of In/Ag from the MgIn/MgAg phase to MgH2. Such a diffusion process is coupled with the decomposition of MgH2, leading to the microstructural transition from MgH2@MgIn or MgH2@MgAg to corresponding solid solutions. For Mg-In system, the discovery of the intermediate phase Mg3In through in-situ TEM observation indicates that the dehydrogenation process is a two-step reaction dominated by the diffusion of In. Meantime, the improved hydrolysis performances of the MgH2@MgIn and MgH2@MgAg composites are primarily attributed to the direct participation of MgIn/MgAg in the hydrolysis reaction, providing more active sites for accelerating hydrogen yield. Therefore, the introduction of In or Ag into Mg has provided with noticeable improvements in the hydrogen storage as well as the hydrolysis properties of MgH2.

Compatibility and hydrolytic behaviors of polylactide isomer/poly(butylene succinate) mixtures by the Langmuir technique

The compatibility and hydrolytic behaviors of the monolayer mixtures of biodegradable stereochemical polylactide (l-PLA or dl-PLA) and poly(butylene succinate) (PBS) were studied by the Langmuir technique at the air/water interface. The π-A behaviors of two binary systems, well mixed and unmixed, were compared with each other to demonstrate their compatibility. From the changes in the occupied area and the transition region, the compatibility of l-PLA/PBS monolayer mixtures decreased with increasing PBS composition while dl-PLA/PBS monolayer mixtures showed better compatibility than l-PLA/PBS monolayer mixtures. Since PBS monolayers at a pH of 6.8 showed a long transition region of approximately 5 mN/m due to the conformation change, the change in the PBS transition in the monolayer mixtures was analyzed. The results were in accordance with the occupied area. The hydrolytic behaviors of the homopolymer and mixed monolayers on an alkaline subphase were monitored at a constant surface pressure as a function of exposure time. The compatible monolayer mixtures showed much slower hydrolytic kinetics than their arithmetic averages. This hydrolytic impedance is mainly due to the interaction between both monolayer chains which prevents the ions from attacking the ester bonds of PBS, resulting in a much faster hydrolytic rate than that of PLA.