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1,3-Dioxolan-4-one (DOX) chemistry was exploited for the synthesis of poly(lactic acid) (PLA)-based copolymers. A new DOX monomer, bearing the naturally occurring carvacrol (CarvDOX) as a pendant, ...

In the present work, a novel polymeric coating for mortars protection was prepared via free radical polymerization between methyl methacrylate (MMA) and stearyl methacrylate (STEA) to overcome the well-known technical problems related to the use of commercial Polyacrylic protectives. The physico-chemical properties of MMA_STEA and the effect of different STEA amounts (1.0-2.5-5.0% mol/mol respect to MMA) on MMA_STEA features were determined via 1H NMR and FT-IR spectroscopy, Gel Permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC). Furthermore, the long-term behavior of these polymeric protective agents was evaluated by means of accelerated aging tests exploiting UV radiations. MMA_STEA coatings were applied to air-hardening calcic lime mortars and their performances were studied using different surface techniques: static water contact angles (WCAs), CIELab colorimetric tests, water absorption by capillarity and water vapour permeability (WVP). All measurements were also performed after an UV aging test to study the durability of the coatings applied on mortar. This work demonstrates that a polymer coating prepared starting from methyl and stearyl methacrylates-based comonomers is an efficient way to obtain mortar protectives with satisfactory water repellent behavior, transparency and durability.

PLA-based materials with eugenol moieties covalently bonded to the macromolecular chains were synthesized for potential application in bioactive food packaging. The synthetic strategy relies on the exploitation of O-Carboxyanhydrides (OCAs) as versatile and easily modifiable monomers. More precisely, eugenol-bearing L-malic acid-derived OCA (L-MalOCA) was synthesized and used as monomer, in homo- and co-polymerization reactions. In the latter case, two different ratios of functionalized L-MalOCA were employed, with respect to the standard L-lactic acid-derived OCA (L-LacOCA) monomer. Homopolymer and copolymers were fully characterized and their thermal properties were investigated, highlighting the effect on the final polymer of varying the concentration of the L-MalOCA-derived monomer. A moderate antimicrobial activity was detected for the eugenol-rich L-MalOCA-derived homopolymerization product, making it promising for developments in the field of bioactive and biodegradable PLA-based materials.

Atmospheric pollutants, such as NOx, SO2, and particulate matter, together with water percolation inside the stone pores, represent the main causes of cultural heritage decay. In order to avoid these undesired phenomena, the application of protective coatings represents a reliable solution. In this context, the present study focused on the synthesis of low-fluorine content methacrylic-based (MMA) polymeric resins characterized by seven F atoms (namely F7 monomer) in the lateral chains. Four different percentages (1.0, 2.5, 5.0, and 10.0%) of the present monomer were adopted to obtain a final polymeric structure showing the desired hydrophobicity, processability, and structural and thermal stability (even after accelerated UV aging tests). MMA_F7(1.0) seemed to be the optimal one; therefore, it was further applied onto Candoglia marble. Specifically, the treated substrates showed good surface hydrophobicity, water repellency, and water vapor transpirability. No color variation was observed even after a 1.5-year exposure in a real polluted environment (Monza Cathedral). Interestingly, the application of this coating hindered the atmospheric nitrates penetration inside the stones and, at the same time, it limited the sulfates (gypsum) formation, thus revealing a very promising marbles protection resin.

Poly(3,4-ethylenedioxythiophene) (PEDOT) plays a key role in the field of electrically conducting materials, despite its poor solubility and processability. Various molecules and polymers carrying sulfonic groups can be used to enhance PEDOT’s electrical conductivity. Among all, sulfonated polyarylether sulfone (SPAES), prepared via homogenous synthesis with controlled degree of sulfonation (DS), is a very promising PEDOT doping agent. In this work, PEDOT was synthesized via high-concentration solvent-based emulsion polymerization using 1% w/w of SPAES with different DS as dopant. It was found that the PEDOT:SPAESs obtained have improved solubility in the chosen reaction solvents, i.e., N, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone and, for the first time, the role of doping agent, DS and polymerization solvents were investigated analyzing the electrical properties of SPAESs and PEDOT:SPAES samples and studying the different morphology of PEDOT-based thin films. High DS of SPAES, i.e., 2.4 meq R-SO3−g−1 of polymer, proved crucial in enhancing PEDOT’s electrical conductivity. Furthermore, the DMSO capability to favor PEDOT and SPAES chains rearrangement and interaction results in the formation of a polymer film with more homogenous morphology and higher conductivity than the ones prepared from DMAc, DMF, and NMP.

The first example of solvent-free, organocatalyzed, polymerization of 1,3-dioxolan-4-ones, used as easily accessible monomers for the synthesis of polylactic acid (PLA), is described here. An optimization of reaction conditions was carried out, with p-toluensulfonic acid emerging as the most efficient Br&oslash, nsted acid catalyst. The reactivity of the monomers in the tested conditions was studied following the monomer conversion by 1H NMR and the molecular weight growth by SEC analysis. A double activation polymerization mechanism was proposed, pointing out the key role of the acid catalyst. The formation of acetal bridges was demonstrated, to different extents depending on the nature of the aldehyde or ketone employed for lactic acid protection. The polymer shows complete retention of stereochemistry, as well as good thermal properties and good polydispersity, albeit modest molecular weight.

One-pot in situ polymerization approach was explored for the preparation of polylactide (PLA)-cellulose nano-fibril (CNF) bio-nanocomposites. CNF were first prepared through enzymatic and mechanica ...

Two new water-repellent methyl methacrylate-based resins were synthesized changing the fluorinated pendant chain length of the co-monomers adopted, 2,2,2-trifluoroethyl acrylate and 1H,1H,2H,2H-perfluorooctyl methacrylate. The macromolecular and hydrophobic properties of the resultant polymers were investigated and their photochemical stability was estimated via an accelerated UV aging test. This work demonstrates that a polymeric protective prepared from a co-monomer bearing a short fluorinated pendant chain is characterized by more satisfactory hydrophobic and durability features than those of long fluorinated pendant chain-based polymers.

In the present paper, a new fluorine based methacrylic monomer, 1H,1H,2H,2H-Perfluoro-octyl-methacrylate (POMA), was synthesized via esterification reaction from methacryloyl chloride and 1H,1H,2H,2H-Perfluoro-1-octanol. Furthermore, POMA was used to prepare with methyl methacrylate (MMA) via free radical polymerization a novel fluorinated methacrylic polymer (MMA_POMA), in order to overcome the well-known technical problems related to the use of acrylic monomer-based commercial protectives, such as Paraloid B72 ® . Indeed, in Paraloid B72 ® −obtainable from the copolymerization reaction of ethyl methacrylate (EMA) and methyl acrylate (MA)- the presence of an acrylic hydrogen atom in alpha to the carbonyl group can start photo-chemical degradation reactions that are able to promote fungi attack and proliferation. The properties of MMA_POMA and the two references synthesized, EMA_MA and EMA_MA_POMA −in terms of macromolecular structure, molecular weights, thermal features and water repellency- were determined; furthermore, the long-term behavior of these polymeric protective agents was estimated by means of accelerated aging tests exploiting UV radiations. Their behavior over time was checked via Size Exclusion Chromatography (SEC), Fourier Transform Infrared (FT-IR) spectroscopy and biodegradation assay. Lastly, MMA_POMA resin was applied on two marble substrates −Calcite and Dolomite- and its wetting properties were successfully assessed and compared to the same features displayed by the reference polymers. This work demonstrates that a polymer protective prepared starting from methacrylic and fluorinated monomers, i.e. MMA and POMA, is an efficient way to obtain resins with satisfactory water repellent properties and enhanced durability than acrylic based polymers without the use of any photo stabilizer additive.

The in situ polymerization of l -lactide in the presence of various amounts of cellulose nanocrystals (CNC) is described. CNC was prepared efficiently by acidic hydrolysis of cotton linters. Molecular weight, morphology, thermal, mechanical and crystallization properties of the PLA-CNC nanocomposites were evaluated. From size-exclusion chromatography (SEC) analysis, the actual occurrence of chemical bond between CNC and PLA can be assessed. The effect of CNC has been evaluated through differential scanning calorimetry (DSC) analysis, which highlights the probable formation of α′ crystals in the obtained materials. More importantly, from thermogravimetric analysis (TGA) a marked improvement in thermal stability of nanocomposites has been demonstrated, with respect to standard PLA and to previously described PLA-CNC blends. Nanocomposites show also an improvement in rheological properties with respect to standard PLA. In particular, storage modulus greatly increases, indicating a reinforcing effect of CNC. The described in situ synthetic methodology allows an optimal compatibilization between the two entities (PLA and CNC), facing one of the major problems inherent to the preparation of nanocomposites. It leads furthermore to remarkably improved thermal and rheological properties of the obtained materials.

Despite the poor photochemical stability of capsules walls, polyacrylate is one of the most successful polymers for microencapsulation. To improve polyacrylate performance, the combined use of different acrylate-based polymers could be exploited. Herein butyl methacrylate (BUMA)-based lattices were obtained via free radical polymerization in water by adding (i) methacrylic acid (MA)/methyl methacrylate (MMA) and (ii) methacrylamide (MAC) respectively, as an aqueous phase in Pickering emulsions, thanks to both the excellent polymer shells’ stability and the high encapsulation efficiency. A series of BUMA_MA_MMA terpolymers with complex macromolecular structures and BUMA_MAC linear copolymers were synthesized and used as dispersing media of an active material. Rate and yield of encapsulation, active substance adsorption onto the polymer wall, capsule morphology, shelf-life and controlled release were investigated. The effectiveness of the prepared BUMA-based microcapsules was demonstrated: BUMA-based terpolymers together with the modified ones (BUMA_MAC) led to slow (within ca. 60 h) and fast (in around 10 h) releasing microcapsules, respectively.

In functional polymers with tunable hydrophilic behaviour like sulfonated polyarylethersulfone (SPES) high ionic conductance can be obtained directly by increasing the concentration of sulfonic moieties along the macromolecular chain. This, however, often comes to the cost of excessive water sorption, which can lead to membrane rupture and consequent device failure. To overcome this drawback, and to reconcile high hydrophilicity with the high mechanical properties of aromatic polymers, we propose the use of SPES copolymers with a low degree of branching. A series of branched SPES was synthesized using homogeneous (one-pot) copolymerization by replacing an amount up to 0.9% mol of the difunctional monomer 4,4′-dihydroxydiphenyl with the trifunctional 1,3,5-trihydroxybenzene (THB). The polymers were characterized by 1H-NMR spectroscopy, intrinsic viscosity, water sorption measurements, thermogravimetric analysis and differential scanning calorimetry. Like linear SPES, branched SPES is totally amorphous and soluble in polar aprotic solvents, lending itself to easy fabrication of membranes and coatings. Besides reducing the water sorption and in-plane swelling of SPES membranes upon equilibration in liquid, branching also improves the retention of water in swollen membranes.

A new synthesis of methacrylate end-capped Poly(3,4-ethylenedioxythiophene) (PEDOT) was performed: the polymer is soluble in common organic solvents, thus overcoming the well-known technical problems related to the use of commercial PEDOT in different printing technologies, such as screen printing, due to its poor processability and compatibility in formulations with other resins and polymers. The new synthetic method developed is based on the direct oxidative polycondensation of 3,4-ethylenedioxythiophene (EDOT) in the presence of an oxidant species and a cross-linkable end-capper, i.e. methacrylate end-capped EDOT (mEDOT), prepared via Friedel Crafts acylation with methacryloyl chloride. The oxidative polycondensation between EDOT and mEDOT monomers in the presence of a new kind of doping agent, Sulfonated Polyarylethersulfone (SPES)—characterized by different degree of sulfonation (DS)—was conducted, leading to functional end-capped conducting PEDOT (mPEDOT_SPES), with conductivity of 210 S/cm, 50 S/cm higher than the one of commercial PEDOT. Thanks to the enhancement of solubility, leading to better processability, end-capped PEDOTs were formulated with a thermoplastic ink, Plastisol®, and electronic circuits were successfully screen printed on flexible cotton substrates, to obtain printed cross-linkable electronic circuits. The conductive features of mPEDOT_SPESs were successfully compared with the ones of PEDOT and of not-doped end-capped PEDOTs. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

Linear sulphonated poly(arylethersulphone) (SPAES) membranes were tested and compared with Nafion, as electrode modifiers for electroanalytical purposes. Different preparation parameters were evaluated: casting solvent, method of drying and storage, polymer ionic moieties counter-ion. In particular, the casting solvent seems to play a key role in the final modified electrode performances. Four solvents characterized by different boiling point and polarity were tested: dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP). The best electrode, particularly in terms of highest peak currents, was the one prepared using a 1% m/v solution of polymer in NMP, dried at 25 °C in a drying oven. Its performances are explained in terms of a favourable membrane organization enabling a thin layer diffusion and/or a preconcentration mechanism.

Polylactide (PLA)-based polymers, functionalized with biobased antioxidants, were synthesized, to develop an intrinsically active, biobased and potentially biodegradable material for food packaging applications. To achieve this result, phenolic antioxidants were exploited as initiators in the ring opening polymerization of l-lactide. The molecular weight, thermal properties and in vitro radical scavenging activity of the polymers obtained were compared with the ones of a PLA Natureworks 4043D, commonly used for flexible food packaging applications. The most promising synthesized polymer, bearing vanillyl alcohol as initiator (PLA-VA), was evaluated for active food packaging applications. Packaging with PLA-VA films reduced color and fat oxidation of salami during its shelf life. info:eu-repo/semantics/publishedVersion

Oxidative polymerization of tyrosol by horseradish peroxidase (HRP)-H2O2 afforded an insoluble product (oligotyrosol, OligoTyr) consisting of mixture of linear oligomers (up to 11-mer) with limited benzylic branching points, as evidenced by ESI-MS and solid state 13C NMR analysis. OligoTyr proved to be significantly more active than tyrosol in several antioxidant assays and was not toxic to human osteosarcoma SaOS-2 cells, stimulating alkaline phosphatase (ALP) activity at day 7 in a similar manner as tyrosol. However, when loaded at 5% w/w into highly porous polylactic acid (PLA) scaffolds featuring hierarchical structures, OligoTyr caused a significant increase in the ALP activity of SaOS-2 cells compared to PLA alone, while tyrosol was completely inactive. A release of ca. 5% from PLA was determined after 1 week in a physiological medium. No significant influence on calcium release from PLA scaffolds containing 5% β-tricalcium phosphate was observed.

Providing self-cleaning properties to polymeric materials has become a pressing issue for a number of applications ranging from building materials to solar panel covers or domestic uses. Highly versatile multilayer polymeric/TiO 2 composites with double self-cleaning properties implying both photo-oxidation and anti-sticking are here proposed. The hydrophobic side was obtained by synthesizing UV and thermal resistant sulfonated polyethersulfone (SPES) by a novel procedure involving the use of hydrophobic ionic liquids and controlling the morphology during deposition. On the other side, the photo-active self-cleaning titania obtained by an ad hoc procedure (developed to preserve the polymeric support features) maintains the material clean upon light exposure.

To overcome the well-known technical problems of Poly(3,4-Ethylenedioxythiophene) (PEDOT), i.e. difficult processability and patterning, due to its poor solubility in common organic and inorganic solvents, PEDOTs characterized by a full miscibility in the reaction solvents used, were successfully synthesized by a direct oxidative polycondensation reaction between Ethylenedioxythiophene (EDOT) and an oxidant species, i.e. ferric sulfate, in four organic reaction solvents: N, N-dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP).The oxidative polycondensation of EDOT in the presence of Sulfonated Polyarylethersulfone (SPAES) as doping agent characterized by three increasing degree of sulfonation (DS), i.e. 0.5, 0.75 and 1.0 (meq SO3-·g-1 of polymer), was performed for the first time, leading to a new conducting material: PEDOT_SPAES. PEDOT_SPAES can be easily processed and casted onto the surface of glassy carbon electrodes, reaching better electrochemical performances with respect to the precursors.PEDOT_SPAES chemical structure was investigated via wide-angle scattering (WAXS): comparing WAXS spectra of unmodified PEDOT and commercial PEDOT doped with 2-Naphthalenesulfonic acid, having crystalline structures, with the spectra of PEDOT_SPAESs, that are characterized by amorphous structures, it is possible to assess that for the first time PEDOT-based materials doped with SPAES were synthesized.To overcome the well-known technical problems of Poly(3,4-Ethylenedioxythiophene) (PEDOT), i.e. difficult processability and patterning, due to its poor solubility in common organic and inorganic solvents, PEDOTs characterized by a full miscibility in the reaction solvents used, were successfully synthesized by a direct oxidative polycondensation reaction between Ethylenedioxythiophene (EDOT) and an oxidant species, i.e. ferric sulfate, in four organic reaction solvents: N, N-dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP).The oxidative polycondensation of EDOT in the presence of Sulfonated Polyarylethersulfone (SPAES) as doping agent characterized by three increasing degree of sulfonation (DS), i.e. 0.5, 0.75 and 1.0 (meq SO3-·g-1 of polymer), was performed for the first time, leading to a new conducting material: PEDOT_SPAES. PEDOT_SPAES can be easily processed and casted onto the surface of glassy carbon electrodes, reaching better electroch...

Polylactic acid (PLA) nanocomposites were prepared via “in situ” ring opening polymerization (ROP) of lactide using a montmorillonite, Cloisite 15A, employed after surface treatment with 3-Glycidoxypropyltrimethoxysilane. The dispersion of the nanoparticles was checked using Wide Angle X-Ray Scattering (WAXS) and Transmission Electron Microscopy (TEM); both the effects of different amounts of montmorillonite and silane were measured on molecular weights and on thermal and rheological properties, using Size Exclusion Chromatography (SEC), Differential Scanning Calorimetry (DSC), thermogravimetric analyses (TGA), and rheological analyses. It was found that even very low amounts (0.1% w/w) of nanoparticles greatly affect nanocomposites properties. Unmodified montmorillonite tends to decrease molecular weights, deactivating the catalytic system used for ROP of lactide, but when epoxy silane is present molecular weights increase. Melt crystallization temperatures increase with modified nanoparticles, which enhance crystallization process. TGA analyses show that when pure montmorillonite is present, nanocomposites have lower thermal stability with respect to standard PLA; when silane is used thermal stability can get much higher than standard PLA as silane content increases. The rheological behaviour of nanocomposites shows that melt viscosity is far higher than that of standard PLA at low shear rates and also a marked shear thinning behaviour can be achieved.

Polyamide 11 (PA11) is a bio-based technopolymer synthesized using 11-aminoundecanoic acid from castor oil. In this work star-shaped PA11 structures are obtained via one-pot copolycondensation of 11-aminoundecanoic acid with a multifunctional agent, either 3-functional bis hexamethylentriamine or tetra-functional 2,2,6,6-tetra[β-carboxyethylcyclohexanone]. A theoretical model predicting the macromolecular complexity of the star shaped polycondensates that result from the reaction is used to interpret the rheological behavior of the synthesized samples, that is found to be strongly affected by the presence of branching. It is shown that melt properties can be modulated, for easier processability, by simply controlling monomer feed ratio and conversion of the copolycondensation reaction. In the range of comonomer functionality and content explored, thermal properties do not significantly vary with changing macromolecular architecture. All star-shaped polyamide samples easily crystallize and their structural characterization above room temperature shows that upon heating they reversibly undergo the alpha-gamma crystal phase transition that is typical of linear PA11. Investigation of the effect of branching on the mechanical properties shows that careful selection of chain controller type and amount allows to obtain star-shaped PA11 samples with ad-hoc modulated melt viscosity and preserved material’s mechanical performance.

Thermal behavior of polylactic acid (PLA)/nanosilica nanocomposites prepared via bulk ring opening polymerization from lactide was investigated by differential scanning calorimetry and thermogravimetric analysis (TGA). Both unmodified nanosilica and modified by surface treatments with different amounts of two distinct silanes were used. Samples containing pure silica show enhanced crystallization processes; with silane-modified silica this effect is magnified, especially in the case of materials with high loadings of epoxy silane. Nonisothermal crystallization temperatures become higher and isothermal crystallization kinetics show a marked increase of Kinetic constant (Kc). TGA analyses show that, when pure nanosilica is present, nanocomposites have a thermal stability far greater than the one of standard PLA, starting their degradation at temperatures up to 70 � C higher than the ones of pure PLA. When silanes are present, thermal stability lowers as silane content increases, but it is anyway higher than the one of the pure polymer. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 3057-3063, 2013

Floating photocatalytic devices are highly sought-after as they represent good candidates for practical application in pollutant remediation of large water basins. Here, we present a multilayer floating device for the photocatalytic remediation of contaminants present in water as well as of volatile species close to the water surface. The device was prepared on a novel tailored ter-polymer substrate based on methylmethacrylate, &alpha, methylstyrene and perfluoroctyl methacrylate. The ad hoc synthesized support presents optimal characteristics in terms of buoyancy, transparency, gas permeability, mechanical, UV and thermal stability. The adhesion of the TiO2 top layer was favoured by the adopted casting procedure, followed by a corona pre-treatment and by the deposition of an intermediate SiO2 layer, the latter aimed also at protecting the polymer support from photocatalytic oxidation. The device was characterized by contact angle measurement, UV-vis transmittance and scanning electron microscopy. The final device was tested for the photocatalytic degradation of an emerging water pollutant as well as of vapors of a model volatile organic compound. Relevant activity was observed also under simulated solar irradiation and the device showed good stability and recyclability, prospecting its use for the photocatalytic degradation of pollutants in large water basins.

Linear and star-branched polyamide 12 were prepared in the presence of mono- and multifunctional acid agents. Molecular masses and molecular mass distributions are discussed according to our model recently presented and are compared with the data obtained by Flory's model. End group titration and SEC data are discussed. Oligomerisation data confirm the general validity of our model.

Polylactide nanocomposites containing different loadings of nanosilica were prepared by employing bulk ring opening polymerization from lactide. Nanosilica was used as such and after surface treatment with different amounts of two distinct silanes. The effects on the properties of the material were evaluated comparing the samples containing organosilane-modified nanosilica with poly(lactic acid) (PLA) containing unmodified nanosilica. A standard linear PLA and an industrial “film grade” PLA (PLA Natureworks 4032D) were used as reference. Pure silica tends to decrease the molecular weight of the material, deactivating the catalytic system but when silanes are present on the surface, molecular weights are similar to the ones of standard and industrial PLA. Transmission electron microscopy analysis shows that silanes improve the dispersion of the mineral, while rheologic curves suggest that when silanes are present melt viscosity increases markedly at zero shear and decreases faster as the shear rate increases. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013