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Novel biodegradable nanocomposite membranes were prepared using a chemo-enzymatic route. Polyester-urethane-urea matrix was obtained from poly(e-caprolactone) diol, isophorone diisocyanate (IPDI), ...

In this work, the chemical modification of cellulose nanocrystals (NCs) using an enzyme as a catalyst has been performed by a “grafting from” reaction, in order to covalently functionalize the external surface of NCs with both poly(L-lactic acid) (PLLA) and poly(ε-caprolactone) (PCL) by ring-opening polymerization. Firstly, cellulose nanocrystals were prepared from commercial cellulose microcrystals by acid hydrolysis and then functionalized by using Yarrowia lipolytica lipase immobilized on Lewatit resin as a catalyst. To confirm the success of the grafting reactions, H-NMR has been performed as well as FT-IR and Raman spectroscopy. Moreover, thermogravimetric analysis has been used to determine the amount of polymeric chains grafted onto the surface of cellulose nanocrystals. Furthermore, the crystalline nature of the polymeric chains grafted onto the cellulose surface has been studied by DSC, X-ray scattering, as well as SAXS analysis. To our knowledge, it is the first time that a biocatalyst approach has been used to obtain biopolymeric functionalized cellulose nanocrystals., This research was funded by the Ministerio de Ciencia e Innovación (PID2021-123753NB-C31; PID2020-119047RB-I00).

Design of a smart drug delivery system is a topic of current interest. Under this perspective, polymer nanocomposites (PNs) of butyl acrylate (BA), methacrylic acid (MAA), and functionalized carbon nanotubes (CNTsf) were synthesized by in situ emulsion polymerization (IEP). Carbon nanotubes were synthesized by chemical vapor deposition (CVD) and purified with steam. Purified CNTs were analyzed by FE-SEM and HR-TEM. CNTsf contain acyl chloride groups attached to their surface. Purified and functionalized CNTs were studied by FT-IR and Raman spectroscopies. The synthesized nanocomposites were studied by XPS, 13C-NMR, and DSC. Anhydride groups link CNTsf to MAA–BA polymeric chains. The potentiality of the prepared nanocomposites, and of their pure polymer matrices to deliver hydrocortisone, was evaluated in vitro by UV–VIS spectroscopy. The relationship between the chemical structure of the synthesized nanocomposites, or their pure polymeric matrices, and their ability to release hydrocortisone was studied by FT-IR spectroscopy. The hydrocortisone release profile of some of the studied nanocomposites is driven by a change in the inter-associated to self-associated hydrogen bonds balance. The CNTsf used to prepare the studied nanocomposites act as hydrocortisone reservoirs.

Nonlinear refraction and absorption properties to twelve ionic liquids were measured by the Z-scan technique. k/dn/dT value reference was determinate by using only one measure. An Influence of anion and cation to nonlinear optical properties was analysed. Cations with mayor length chain and aromatic systems presented better nonlinear optical properties that the alicyclic cations. [NO3] anion presented the best contribution to these properties independently of cation used.

The optical properties of six ionic liquids, modified with 1-buthyl-3-methylimidazolium and 1-ethyl-3-methylimidazolium cations, to form a bi-ionic liquid, was determined by the z-scan technique, revealing a negative nonlinear refractive index, which can be tailored, to some extent, by the composition of the liquid.

Enzymatic polymerization has a large potential as an environmentally friendly synthetic process. Lipase is a renewable catalyst with high catalytic activity from which it is possible to develop a versatile method for the production of sustainable polyurethanes. In this work oligomeric PCL-diol was synthesized using biocatalysis with immobilized Yarrowia lipolytica lipase (YLL) and diethyleneglycol as initiator. Then, two different linear polyurethanes were prepared. One was obtained directly from the previous synthesized PCL-diol and hexamethylene diisocyanate, named PU, and the other one has been obtained by incorporating L-lysine amino acid as end group (lys-PU). PU and lys-PU disintegration under composting conditions was evaluated. The influence of the presence of L-lysine on the disintegration performance of PU was studied by evaluating the disintegration degree, monitoring the weight loss. Structural and morphological changes were followed by Fourier transformed infrared spectroscopy (FTIR) and by scanning electron microscopy (SEM)., Authors thank Spanish Ministry of Economy, Industry and Competitiveness, MINEICO, ( and MAT2013-48059-C2-1-R MAT2017-88123-P) cofinanced with FEDER funds, Regional Government of Madrid (S2013/MIT-2862) and Consejo Nacional de Ciencia y Tecnología (CONACYT, Grant 153922) for the financial support. M.P. Arrieta and L. Peponi acknowledge the Juan de la Cierva (FJCI-2014-20630) and Ramon y Cajal (RYC-2014-15595) contracts from the MINECO, respectively. Authors also acknowledge Prof. Juan López Martínez (Universitat Politécnica de Valencia, Spain) for his assistance with colorimetric measurements.

In this work we study the clustering of hard spheres (HS) with associating square-well (SW) sites of variable range as a model of polymerization process, like the ring-opening polymerization of the ϵ-caprolactone. We present a systematic Monte Carlo (MC) computer simulation study of the effects of the interaction parameters on the cluster morphology, characterized by the fractal dimension, and compared with experimental results for the poly(ϵ-caprolactone). The cluster morphology depends on the length and energy scales of the system and both can be related to the intrinsic properties of propagating species.

Enzyme-catalyzed synthesis of biopolymers is a growing area of green chemistry because the exquisite selectivity and control of the polymer structure allowed by the enzymatic synthesis. In addition, the metal traces of chemical catalysts are avoided, being this feature particularly useful in biomedical applications. Lipases are remarkable catalysts and they are efficient in the synthesis of several kinds of biopolymers. However, one of the limitations of the industrial application of lipase-catalyzed polymerizations is the cost of commercial immobilized lipases. To overcome this drawback, in this work we present some cheap and simple strategies to produce and obtain immobilized lipases, as well as some examples of biopolymer synthesis using these tailored lipases.

Yarrowia lipolytica (YLL), Candida rugosa (CRL), and porcine pancreatic lipase (PPL) were employed successfully as catalysts in the enzymatic ring-opening polymerization (ROP) of e-caprolactone in the presence of 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF 4 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), 1-butylpyridinium tetrafluoroborate ([BuPy][BF 4 ] ), 1-butylpyridinium trifluoroacetate ([BuPy][CF 3 COO]), 1-ethyl-3-methylimidazolium nitrate ([EMIMI][NO 3 ]) ionic liquids. Poly(e-caprolactone)s (PCLs) with molecular weights (M n ) in the range of 300-9000 Da were obtained. 1 H- and 13 C-NMR analyses on PCLs formed by YLL, CRL, and PPL showed asymmetric telechelic α-hydroxy-ω-carboxylic acid end groups. Differences between CP-MAS and MAS spectra are observed and discussed in terms of morphology. MALDI-TOF spectra show the formation of at least seven species. Differential scanning calorimetry (DSC) and Wide Angle X-Ray Scattering (WAXS) results demonstrate the high degree of crystallinity present in all the polyesters.

The one-pot biocatalytic synthesis of amphiphilic polymers consisting of an isosorbide headgroup and a hydrophobic polyester chain is described. The immobilized lipase of Yarrowia lipolytica (YLL) catalyzed ring-opening polymerization of e-caprolactone (e-CL) initiated by the multifunctional initiator isosorbide. Polymerizations were carried out in bulk at 70, 80, 90 and 120 °C. The highest reaction rates for e-CL polymerization resulted for YLL immobilized on macroporous resins: Lewatit VP OC 1026 at 80 °C, and the strongly acidic Lewatit K-2629 at 90°C. Structural analyses were made by MALDI-TOF, 1 H, and 13 C-NMR.

A new lipase from the yeast Yarrowia lipolytica was isolated and used in the enzymatic ring-opening polymerization of lactones. The effect of used commercial oil from a vacuum pump (instead of olive oil) and in the presence of wheat flour was evaluated. It was found that lipase production is favored when wheat flour and used commercial oil is added instead of olive oil with an incubation time of 16.5 h at 29°C and 250 rpm. Lipase shows a specific activity of 3.47 nmoles of 4-methyl umbelliferone released/mg of protein/min. In this way, preculture step can be avoided and an important reduction in production time can be obtained. In vitro polymerization of e-caprolactone at different temperatures in the presence of n-heptane for 15 days produces low-molecular-weight polyesters with unique multiphase morphology. Polyesters were characterized by NMR (solution and solid-state) spectroscopy, differential scanning calorimetry (DSC), Fourier-transformed infrared, wide-angle X-ray scattering and MALDI-TOF. Polyester crystallinities calculated by DSC were high, as expected for low-molecular-weight PCLs. Final polymer possesses carboxylic acid and hydroxyl end-groups, as determined by 1H- and 13C NMR analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008

The enzymatic synthesis of ¿¿¿-telechelic polycaprolactone diols (HOPCLOH) and block copolymers was studied. Synthesis of ¿¿¿-telechelic PCL diols was carried out by enzymatic ring opening polymerization with Yarrowia lipolytica lipase immobilized on Lewatit VP OC K2629 and Amberlyst 15, and using ethylene glycol, diethylene glycol and polyethylene glycol as initiators. Biodegradable linear polyester-urethanes were prepared from synthesized PCL diols and hexamethylenediisocyanate (HDI). Polyester-urethanes degradation was studied using thermogravimetric analysis (TGA) and hydrolysis (alkaline, acidic and neutral). It was found that content of ether linkages influences the thermal stability and hydrolytic degradation behavior of the analyzed polyurethanes. Hydrolytic degradation proceeds faster in alkaline media, in agreement with the expected susceptibility of ester COO¿ bonds to degradation in the polyester urethanes.

Yarrowia lipolytica lipase (YLL) was used as catalyst in the enzymatic ring-opening polymerization (ROP) of ε-caprolactone. This low-cost solid-state lipase produces low-molecular-weight polyesters with unique multiphase morphology as determined by carbon-13 NMR. YLL attaches sugar head groups to polycaprolactone in a one-pot biocatalytic pathway. Synthesis of α-ω-telechelic (polymer with two reactive hydroxyl end groups) PCL diols is achieved by enzymatic ROP with YLL immobilized on the macroporous resin Lewatit VPOC 1026, and in the presence of diethylene glycol or poly(ethylene glycol). Biodegradable linear polyester urethanes are prepared by polycondensation between synthesized PCL diols and hexamethylene-diisocyanate.

Yarrowia lipolytica lipase (YLL) was used as catalyst in the enzymatic ring-opening polymerization (ROP) of e-caprolactone. This low-cost solid-state lipase produces low-molecular-weight polyesters with unique multiphase morphology as determined by carbon-13 NMR. YLL attaches sugar head groups to polycaprolactone in a one-pot biocatalytic pathway. Synthesis of α-ω-telechelic (polymer with two reactive hydroxyl end groups) PCL diols is achieved by enzymatic ROP with YLL immobilized on the macroporous resin Lewatit VPOC 1026, and in the presence of diethylene glycol or poly(ethylene glycol). Biodegradable linear polyester urethanes are prepared by polycondensation between synthesized PCL diols and hexamethylene-diisocyanate.

We study de nonlinear optical properties of three ionic liquids of family [BMIM]. The ionic liquids are 1-buthyl-3-methylimidazolium tetrafluoroborate, 1-buthyl-3-methylimidazolium trifluoroacetate, and 1-buthyl-3-methylimidazolium Bis((trifluoromethyl)sulfonyl)imide. We calculate the static molecular polarizability (α) and hyperpolarizability (β,γ) using PM3 model and determinate experimentally the third-order nonlinear optical susceptibility χ(3), using z-scan technique. Interest in nonlinear optics has grown in recent years. High performance electro-optic switching elements for telecommunications and optical information processing are based on materials with high nonlinear optical (NLO) properties. This NLO are presents when a laser interacts with the materials, and can be studied at to levels: molecular o bulk.

9 páginas.-- Editores: H. N. Cheng y Richard A. Gross., The enzymatic synthesis of α-ω-telechelic polycaprolactone diols (HOPCLOH) and triblock copolymers was studied. Synthesis of α-ω-telechelic PCL diols was achieved by enzymatic ring opening polymerization with Yarrowia lipolytica lipase immobilized on a macroporous resin Lewatit VP OC 1026, and using diethylene glycol and poly(ethylene glycol) as initiators. Biodegradable linear polyester-urethanes were prepared from synthesized PCL diols and hexamethylenediisocyanate (HDI). Depending on the length of PCL in HOPCLOH, the polymers were amorphous or semicrystalline. Measured mechanical properties strongly depend upon the degree of crystallinity of HOPCLOH.

because they are organic salts that are in the liquid state at ambient conditions. The most important ch aracteristic of ILs is that they show negligible vapor pressure, so they are environmentally benign. Nowadays, a large variety of ILs is available. Among other properties, they have thermal stability, high ionic conductivity, miscibility with other solvents, and recyclable nature. On other way, the huge potential of organic materials in optical applications has motivated the development of new compounds and the study of their optical properties, but only few reports on its physicochemical and optical properties have been published

Here we propose optofluidic spherical microlenses that can change their focal distance by varying the refractive index of the liquid that composes them. These lenses are fabricated in the bulk of a polymeric mixture. Results of a characterization study of the profile of the lenses, the image forming capability, and the behavior of the focal distance as a function of the refractive index are presented. Ionic liquids are suggested as a source of liquids useful for fabricating this type of lens.