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Currently, there is a great demand for functional materials with effective pathogen-killing properties. In this research, we describe the use of green technology “reactive extrusion” for the synthesis of potent antimicrobial materials based on Ethylene-vinyl alcohol copolymer (EVOH). Herein, the antimicrobial agent, copper (II) acetate was used without pretreatment and introduced into the EVOH matrices at high temperatures. The thermal reaction of copper (II) acetate within the EVOH matrices and their effect on the thermal and thermomechanical properties of the polymer were investigated in regards to their concentration. The physicochemical, thermal, and rheological features, as well as, metal salt release kinetics were reported. The antimicrobial agent had significant effects on the properties of the matrix. Results showed a reduction in the glass transition temperatures and storage modulus of the materials in response to the incorporation of copper (II) acetate. Finally, the antimicrobial activity of the products was studied and demonstrated a possibility to create antimicrobial materials in a one-step, solvent-free extrusion process.

Environmental and ecological issues have led to the development of new sustainable channels for the recovery of dredged sediments. One of the major difficulties of sediment valorization lies in particular in its very heterogeneous composition. For example, the presences of heavy metals and organic matter have a significant influence on the environmental impact of materials formulated with sediment. Some heavy metals such as antimony, mercury, lead, and cadmium in high concentrations are dangerous to the body. Trace metals trapped in sediments are transformed through complex biogeochemical processes. They subsequently associate with organic matter to form clay-humic groups that define the degree of sediment pollution. The Harbour Dredging Sediments (HDSs) used were classified as non-hazardous waste in accordance with Directive 12/12/14/EC. The purpose of this study is to evaluate the environmental impact of the use of HDS from active lagoon in the formulation of self-compacting concrete (SCC) with the objective of incorporating a high sediment content, obtaining materials with a low environmental impact and ensuring compressive strength of a C25/30 class concrete. Three HDSs are being studied that have a significant impact their difference by their fines content at 125 μm. Sediments recovered from the active lagooning process have not undergone any physical, chemical, or thermal treatment. The DMDA (Densified Mixture Design Algorithm) method is used to optimize the composition of "sediment" SSCs. The communication focuses on mortars equivalent to these "sediment" SCCs (SCMs). Sediment represents about 20% of the granular composition with a sediment-to-cement ratio of 80%. Compressive strengths are greater than 25 MPa and tensile strengths are in the range of 3 to 8 MPa at 28 days of curing. From an environmental point of view, all heavy metals are stabilized except nickel. In particular, there has been a considerable decrease in the levels of sulfate, total organic carbon, and chloride. The different SCMs are classified as inert, clinker hydration produces hydrates that capture and stabilize heavy metals in the cementitious matrix. The results obtained show that HDSs could be used as a secondary raw material in the formulation of self-compacting concretes.

Municipal solid waste incineration generates large quantities of bottom ash that should be recycled. Current use of municipal solid waste incineration bottom ash (MSWI-BA) in cementitious materials is mostly in Ordinary Portland Cement (OPC). This paper considers using MSWI-BA as sand substitution in Calcium Sulfoaluminate Cement (CSA) as an alternative to OPC. A comparison between OPC and CSA mortars containing 0–2 mm MSWI-BA is conducted. The MSWI-BA used was treated to remove the ferrous and non-ferrous metals in order to obtain a better mineral fraction. Different percentages (0%, 25%, 50%, 75%, and 100%) of standard sand were substituted by MSWI-BA based on equivalent volume. Experimental results showed that the compressive strength and porosity of the CSA mortars were superior to OPC after substitution at 1, 7, 28, and 90 days. The compressive strength of OPC mortars with 25% substitution decreased by 40% compared to 11% for CSA mortars at 90 days. This is due to the difference in pH between the two cement pastes as OPC in contact with the MSWI-BA leads to a reaction with the aluminum content which releases hydrogen gas, increases the porosity, and decreases the compressive strength. © The Author(s) 2020.

In this work, poly(trimethylene carbonate) (PTMC)-based multiarm supramolecular polymers bearing self-complementary triuret and tetrauret hydrogen-bonding motifs (HBMs) at the chain ends were synth...

In this work, thermoreversible poly(trimethylene carbonate) (PTMC) based networks with different crosslinking densities were obtained by Diels–Alder (DA) reaction between furan-functionalized PTMC precursors and a bismaleimide. Furan-grafted PTMC with various functionalities determined by 1H-NMR analyses were prepared from telechelic PTMC oligomer, glycerol, 4,4′-methylenebis(cyclohexyl isocyanate) (H12MDI) and furfuryl alcohol. The formation of network structures by DA reaction between furan and maleimide groups were proved by Fourier-transform infrared spectroscopy (FT-IR). Although both exo and endo DA adduct forms exist, the thermally more stable exo form dominates. The thermoreversibility of networks was evidenced by FT-IR, solubility, differential scanning calorimetry (DSC) and rheology experiments at different temperatures. By increasing furan functionality or node concentration, denser and stiffer networks could be formed with higher Young's modulus and true stress at break in tensile tests, as well as higher crossover temperature, which indicates a nominal transition from elastic behavior to viscous state. The disruption of networks was found to occur in high temperature ranges from 130 to 160 °C, depending on their crosslinking density.

International audience; Currently, there is very strong interest to replace synthetic polymers with biological macromolecules of natural source for applications that interact with humans or the environment. This research describes the development of drug delivery hydrogels from natural polymers, starch, lignin and hemicelluloses by means of reactive extrusion. The hydrogels show a strong swelling ability dependent on pH which may be used to control diffusion rates of water and small molecules in and out of the gel. Also the hydrogels degradation rates were studied in a physiological solution (pH 7.4) for 15 days. The results indicated that for all three macromolecules, lower molecular weight and higher level of plasticizer both increase the rate of weight loss of the hydrogels. The degradation was extremely reduced when the polymers were extruded in the presence of a catalyst. Finally the dynamic mechanical analysis revealed that the degradation of the hydrogels induce a significant reduction in the compressive modulus. This study demonstrates the characteristics and potential of natural polymers as a drug release system.

International audience; Hemicellulose materials are arguably the second most abundant renewable component of lignocellulosic biomass after cellulose. They are relatively under-utilized hetero-polysaccharides present in lignocellulosic biomass. In this research an alkaline treatment was optimized for extraction of polymeric hemicellulose from fully bleached hardwood pulp (B-HWP) and partially delignified switchgrass (SWG). The hemicellulose extracted from B-HWP was relatively pure with zero percent lignin and 89.5% xylose content whereas the partially delignified SWG hemicellulose contained about 6-3% lignin and 72–82% xylose, depending on the NaOH concentration during extraction (3–17% NaOH solution). A maximum molecular weight of SWG hemicellulose of 64,300 g/mol was achieved for the 10% NaOH solution extraction, whereas the MW of B-HWP hemicellulose at 10% NaOH solution extraction was lower at 49,200 g/mol. We have demonstrated that the residual lignin in SWG hemicellulose lowered the system Tg and this might be utilized as a way to increase the applications of hemicellulose in high value biomaterials. Furthermore, the hemicellulose could be crosslinked with zirconium to develop a water resistant gel for coating or adhesive applications. Our results showed that the loading stress required to break an hemicellulose based adhesive connection between two paper surfaces was 0.89, 2.02, 2.75, 3.46, and 3.11 (MPa) for 2, 4, 6, 8 and 10% AZC samples, indicating that up to about 8% AZC crosslinker in the hemicellulose increases the adhesive behavior of the material.

Stem-cell-based therapy is a promising approach for the treatment of a myriad of diseases and injuries. However, the low rate of cell survival and the uncontrolled differentiation of the injected stem cells currently remain key challenges in advancing stem cell therapeutics. Hydrogels are biomaterials that are potentially highly effective candidates for scaffold systems for stem cells and other molecular encapsulation approaches to target in vivo delivery. Hydrogel-based strategies can potentially address several current challenges in stem cell therapy. We present a concise overview of the recent advances in applications of hydrogels in stem cell therapies, with a focus particularly on the recent advances in the design and approaches for application of hydrogels in tissue engineering. The capability of hydrogels to either enhance the function of the transplanted stem cells by promoting their controlled differentiation or enhance the recruitment of endogenous adult stem cells to the injury site for repair is also reviewed. Finally, the importance of impacts and the desired relationship between the scaffold system and the encapsulated stem cells are discussed. - 2008-2011 IEEE. Manuscript received June 9, 2017; revised January 8, 2018 and March 14, 2018; accepted March 15, 2018. Date of publication April 12, 2018; date of current version February 15, 2019. This publication was made possible by the NPRP grant [NPRP 9-144-3-021] from the Qatar National Research Fund (a member of The Qatar Foundation) and the grant GCC-2017-005 from GCC research program. The statements made herein are solely the responsibility of the authors. W. Farhat would also like to acknowledge the partial funding for his work by the French Ministry of Europe & Foreign Affairs. A. Hasan would like to thank the Biomedical Research Center at Qatar University for its resources to Anwarul Hasan’s lab. (Corresponding authors: Anwarul Hasan; Firas Kobeissy.) W. Farhat is with the College of Natural Resources, Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695 USA, with the Université de Lyon, Ingénierie des Matériaux Polymères (IMP), UMR CNRS 5223, Université Jean Monnet, Saint-Etienne F-42023, France, and also with the Faculty of Medicine, Department of Biochemistry and Molecular Genetics, American University of Beirut Medical Center, Beirut 1107 2020, Lebanon (e-mail: farhatw92@gmail.com). Scopus

International audience; The compatibilization of PC/PS (70/30 wt%) blends was realized by the addition of 1.125, 2.5 and 5 wt% of SEBS-g-PC. SEM pictures revealed that the droplet-matrix microstructure was refined, from droplets of 0.787 μm diameter to 0.420 μm. The complex viscosity decreased, and, correlated to the size of the droplets, was the result of the decrease of the interfacial tension between PC and PS. The transition temperature of the PS increased for 12 °C with 5 wt% of SEBS-g-PC, showing a compatibilizing effect of this copolymer. The two maxima observed in Van Gurp-Palmen plots merger confirming the compatibilization. Finally, mechanical properties were widely improved. Impact strength evolved from 3.8 to 6.9 kJ m−2, and elongation at break was multiplied by two (from 19.6 to 40.5%) when 5 wt% of copolymer is added. The interfacial adhesion increase was due to the compatibilization effect of the SEBS-g-PC onto PC/PS blends.

This paper presents the results of an experimental investigation on the substitution of natural sand by municipal solid waste incineration (MSWI) bottom ash in concrete applications in order to preserve non-renewable natural resources and then, reduce the carbon footprint of buildings sector. First of all, physical, chemical and leaching test have been performed on upgraded MSWI bottom ash and the obtained results were compared to natural sand usually used in France in concrete applications. In the second time, a preliminary campaign carried out by utilizing 100% MSWI bottom ash 0-2 mm for the substitution of natural sand in the mortar applications. Physical characterization revealed that grain size distribution and specific gravity of MSWI bottom ash are similar to natural sand identified. However, water absorption content (WAb equal to 7.50%) of bottom ash is higher than natural sand. In order to improve the workability of mixing, a superplasticizer has been used at 0%, 1.5%, 2% and 3% by weight of cement. After 14 days of curing, compressive and flexural strengths were performed on hardened samples. Results showed compressive strength of bottom ash samples ranging from 19.4 MPa (without superplasticizer) to 33.3 MPa (3% of superplasticizer), following a linear trend while flexural strength ranging 4.7 MPa to 5.4 MPa. No health threat has been detected for the MSWI bottom ash 0-2 mm fraction and it was categorized as non-hazardous waste according to European legislation of waste. Study developments are currently oriented towards the analysis of physical, mechanical and thermal properties of concrete containing bottom ash and durability assessment.

International audience; Hemicelluloses, due to their hydrophilic nature, may tend to be overlooked as a component in water-resistant product applications. However, their domains of use can be greatly expanded by chemical derivatization. Research in which hydrophobic derivatives of hemicelluloses or combinations of hemicelluloses with hydrophobic materials are used with to prepare films and composites is considered herein. Isolation methods that have been used to separate hemicellulose from biomass are also reviewed. Finally, the most useful pathways to change the hydrophilic character of hemicelluloses to hydrophobic are reviewed. In this way, the water resistance can be increased and applications of targeted water-resistant hemicellulose developed. Several applications of these materials are discussed.

International audience; Polymer materials with antimicrobial activity are prepared by UV polymerization of acrylate and methacrylate mixture at room temperature. The antimicrobials are silver acetate and copper (II) acetate, used without pretreatment. Their chemical stability in the acrylate matrix and their effect on the thermal and mechanical properties of the polymer matrix are investigated as a function of their concentration up to 15 wt%. Physico-chemical, thermal, rheological, and morphological analyses as well as the surveillance of metal salts release in aqueous medium are conducted. A significant decrease in the thermal stability of the salts introduced into the acrylate matrix is observed after UV treatment. The metal salts also have significant effects on the properties of the matrix. A plasticization and densification of the material associated with an aggregation of salts up to the percolation at the highest concentration are highlighted. At equal concentrations, the effects are more pronounced in the presence of copper salts. The latter was released more slowly than silver salts from acrylate material.

To create reversible supramolecular ionic networks, ionic cross-links were formed from acid pendant functions in poly(styrene-co-methacrylic acid) copolymers by the addition of calcium carbonate. The random dispersion of acid functions in the polystyrene chain is ensured by NMR analysis. The partial reaction of the calcium carbonate with the carboxylic acids is highlighted by a limewater test. The influence of methacrylic acid and calcium-carbonate contents on the formation of an ionic network has been studied through solubility tests. Two main effects were obtained: the exfoliation of the unreacted calcium carbonate characterized by TEM is due to ionic interactions at the surface of nanometric particles that form the first level of organization of the calcium carbonate. Another part of the calcium carbonate reacts with carboxylic acid and is detached from particles to form clusters as shown by x-ray analysis. Finally, by analyzing the dynamic rheological spectrum, the conclusion that the strength of the ionic bonds arises with the calcium content is made. The interest of such an approach with a wide range of observed phenomena in the material is a one-batch process to make thermoreversible nanocomposite networks. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Dynamic covalent reorganization of polycaprolactone (PCL) and poly(ethylene-co-vinyl alcohol) (EVOH) were realized by solvent free transesterification reactions. Organometallic and organic catalysts effect on these reactions was first evaluated from kinetic studies on small molar mass model reactants. Kinetic constants and activation energies of these second order reverse reactions were calculated. At the higher temperatures, side reactions were observed; they were identified as being principally dehydration reactions. Reactions conducted onto polymers were slower than those on model reactions. This was due to the immiscibility of the used polymers resulting in diffusion controlled reactions. Two competitive types of reactions were detected, since at the catalyst addition, fast induced reorganization of PCL leading to low PCL molar mass decreases the mixing torque, followed by grafting reactions of PCL onto EVOH, resulted in an important increase of the mixing torque. Substitution rate of the EVOH hydroxyl groups were measured up to 14% by 1H-NMR spectroscopy. Increasing substitution rate leaded to a decrease of the copolymer crystallinity and the more substituted copolymers were amorphous. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

International audience; Chemical modification of EVOH in the molten state at 185 degrees C by a grafting from process of poly(epsilon-caprolactone) in batch was studied. (1)H NMR was used to characterize the structure evolutions of PCL grafts. In addition to grafting reactions, dynamic covalent transesterification reactions between EVOH residual alcohols and the polyester grafts led to a redistribution of the PCL grafts length. (Dp) over bar (n) up to 27 and SR up to 80% were obtained. Experiments made in a corotating mini twin-screw extruder also confirmed these results. The effect of the alcohol to caprolactone ratio and catalyst concentration (SnOct(2)) on kinetic evolution showed that few minutes were necessary to complete the polymerization. A kinetic model was proposed and adequate conditions for the synthesis by reactive extrusion were defined.

International audience; EVOH-g-PCL were prepared by a solvent-free reactive extrusion process using a co-rotating twin screw extruder. Kinetic simulations were made of selected reaction conditions at 185 degrees C. Changes in the screw rotation rate resulted in evolution of the residence time distribution and slightly changed the monomer conversion. An increase of the [OH](0)/[Cl](0) ratio made the reactive system more viscous and decreased the overall pumping capacities of the extruder. Increase of the mean residence time, combined with a positive kinetic effect of [OH](0) increase, leaded to an important increase in conversion. For all the conducted experiments, equivalent distribution dispersions and good agreements between calculated conversion and those measured were obtained. An increase in temperature from 185 to 200 degrees C resulted in total conversion.

MSWI bottom ashes constitute particular granular materials because these industrial by-products are the results from the incineration of domestic waste. The field of beneficial use of these waste mainly lies in the road engineering today, like materials of substitution for the traditional natural aggregates, which are usually used in this field. For this reason, the characterisation of the mechanical behaviour of the material—which is currently little developed—proves to be essential in order to perennalize this field of beneficial use, assuring thus the transition “waste MSWI”/“material MSWI”. This paper presents a first approach of the mechanical behaviour under shear triaxial tests. A special methodology is investigated for the realisation of tests, because of the origin and the specificity of the MSWI bottom ash. The analysis of the mechanical behaviour shows a mechanical behaviour similar to the classic granular materials initially dense.

A one-step process is reported to directly synthesize blends of poly(trimethylene carbonate) (PTMC) with a modified granular starch. Trimethylene Carbonate (TMC) ring-opening polymerization is performed in the presence of native starch particles in bulk conditions at 150 °C and the efficiency of metal-free organic catalysts (TBD and phosphazene superbases P1-t-Oct, P2-t-bu, and P4-t-bu) are investigated to replace the organo-metallic stannous octanoate initiator. TMC monomer is successively converted into PTMC and the robustness of organic catalysts is highlighted with significant activities at very low concentrations (

International audience; Transesterification of poly(lactic acid) and poly(ethylene-co-vinylalcohol) was realized in-melt using different catalysts. Reactions were first conducted in an internal mixer and the different reaction parameters effect on exchange reactions and the obtained copolymers were optimized. Among the used catalysts, 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) and Tin(II) bis(2-ethylhexanoate) (Sn(Oct)2) were particularly efficient. In a second part, reactions were made by reactive extrusion. In most of reaction conditions, compatible blends were obtained with a fine micro phase separation. Only under extreme reaction conditions, high temperature and intensive mixing, nanostructured graft copolymers were obtained.

International audience; The reactions between polycarbonate (PC) and polystyrene-block-poly(ethylene-butylene)-block-polystyrene-grafted-maleic anhydride (SEBS–g–MAH) is a novel, convenient, solvent-free, and easy way to create SEBS–g–PC in order to compatibilize polystyrene and PC blends. This study determines the most efficient catalyst among Tin (II) bis(2-ethylhexanoate) (SnOct2), 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD), Titanium tetrabutoxide (Ti(OBu)4) and Sodium 4-hydroxybenzenesulfonate dihydrate (SHBS) in the molten state at 220 °C. From 20 to 30 wt% of SEBS-g-MAH (or KFG) chains became insoluble. The size exclusion chromatography analyses showed the formation of a double distribution due to PC chains scission and grafting reactions onto SEBS–g–MAH with the exception of the Ti(BuO)4 use. Fine microstructures with a percolation effect proved the efficiency of both the TBD and the SnOct2. The PC transition temperature decreased in at least 10 °C, confirmed that only SnOct2 and TBD were efficient to catalyze the grafting reactions. No evolution was observed with the SHBS and Ti(OBu)4.

Polypropylene (PP) was functionalized in the melt by grafting polar monomers using an internal mixer and a corotating twin-screw extruder. 2,5-Bis(tertbutylperoxy)-2,5-dimethylhexane (Luperox 101) and dicumyl peroxide (DP) were the used radical initiators. The polar monomers were itaconic acid (IAc), 2-octen-1-ylsuccinic anhydride (OY), 2-hydroxyethyl methacrylate (HEMA), and 3-allyloxy-1,2-propanediol (AP). Grafting was quantified by FTIR combined to Elemental Analysis. Grafting degree depends mainly on monomer and initiator natures and concentrations. Grafting degree maxima were 3.9, 2, 9.5, and 3.9 wt %, respectively, for IAc, OY, HEMA, and AP. Some properties of the modified PP were evaluated. Thermal analysis indicated that the polarity of PP increased by grafting reaction and size-exclusion chromatography showed that the grafting was not accompanied by a significant Mw and viscosity decrease. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

International audience; Polypropylene/poly(3-hydroxybutyrate-co-hydroxyvalerate) blend (PHBV) and polyethylene/PHBV blend were prepared by twin screw extruder using preformed copolymer (EVOH-g-PHBV) as compatibilizer or with functional polyolefins that can react in situ with the PHBV phase to form POs-g-PHBV. Scanning electron microscopy shows that by using either EVOH-g-PHBV preformed copolymer or formed copolymers in situ both emulsify the phase interface and reduce the interfacial tension, which result in an enhancement on the mechanical properties of compatibilized blends. Enhancement is more or less pronounced depending on the used PO matrix.

International audience; Novel polyurea-urethane (PUU) supramolecular polymer networks based on triuret and tetrauret blocks were synthesized. The network formation was controlled through the conformation of hydrogen bonding moieties and their concentration. FTIR spectroscopy and solubility tests showed the presence of significant hydrogen bonds only in triuret moieties and that these bonds conducted to cross-linked materials at room temperature. Hydrogen bonding association constant, K-assn = 95 M-1, was calculated using H-1 NMR for triuret blocks' self-associations. Dynamic mechanical analysis confirmed that triuret blocks conduct to a network at room temperature and that decross-linking occurs between 105 and 135 degrees C. The tetrauret blocks had a folded conformation at room and relatively low temperatures. The polymers containing these moieties did not cross-link at room temperature and below. Temperature increase favored unfolded conformation and conducted to intermolecular hydrogen bonds and, at high temperature, to cross-linked materials.

International audience; Poly(ethylene-co-vinylalcohol)-grafted-poly(3-hydroxybutyrate-co-hydroxyvalerate) (EVOH-g-PHBV) was prepared by a catalyzed grafting of PHBV onto immiscible EVOH. These reactions were performed at high temperature in the molten state. The choices of Tin(II) bis(2-ethylhexanoate) (Sn(Oct)2) and 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD), as catalyst, were justified by a first study in an internal mixer. The catalyst quantity, reaction temperature and reaction time were optimized to apply them in the conditions of a reactive extrusion process with a co-rotating twin screw extruder. High reaction temperature, from 180 °C to 220 °C, associated to intensive mixing led to efficient grafting of PHBV onto EVOH, compatible with short residence times required. Rheological, thermal and morphological analyses were conducted to characterize the obtained copolymers. Molecular weights were determined by SEC. SEM imaging were made on cryo-fractured surfaces of blends extruded with and without catalyst. In most of reaction conditions, a compatible blend was obtained with a fine micro phase separation. Graftedcopolymers were only obtained when well defined and controlled conditions are applied.

International audience; The non-miscibility of the reactants during solvent free poly-ε-caprolactone grafting onto poly(ethylene-co-vinyl alcohol) (EVOH) dramatically affects reaction kinetics. Different solutions were proposed to accelerate the exchange reactions between poly(ethylene-co-vinyl alcohol) and poly-ε-caprolactone. Reactions were conducted in a batch reactor or a mini twin-screw extruder. The addition of a poly(ethylene-co-vinyl alcohol)-g-poly-ε-caprolactone copolymer increased the compatibility of the reactants and led to a higher reaction rate. This copolymer was either prepared separately and added at the reaction beginning or prepared in situ grafting caprolactone from EVOH. The reactive system evolution was analyzed using molar mass evolution, microstructure characterization, thermal properties and the reactive blend morphology. The compatibilization effect combined with optimized reaction conditions, such as concentration and nature of catalyst and temperature, resulted in an important increase in reaction rates. Among the tested catalysts, 1,5,7-Triazabicyclo [4.4.0]dec-5-ene was a more efficient catalyst for grafting reactions than Tin (II) 2-ethylhexanoate.

Polycaprolactone (PCL) grafting on vinyl alcohol-co-vinyl acetate) (PVA-Ac), was investigated in the melt at high temperature (170°C), below the PVA-Ac melting point, by ring opening polymerization of ϵ-caprolactone initiated by metal alkoxyde sites present in PVA-Ac: no additional initiator was used. The obtained average structures were determined by 1H NMR. As expected, small grafts, with low average polymerization degree (DP), were obtained, between 4 and 12 h of reaction. These DP are due to exchange reactions between hydroxyl groups and PCL growing chains. The PVA-Ac was shown to be partially substituted by short PCL grafts. The DP linearly increased with the initial Lactone/PVA-Ac ratio, and the substituted alcohol sites rate were limited to 63%.It was shown that the used reactive system is characterized by a quazi-living polymerization mechanism. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007