Elisabetta Ranucci

Biodegradable Polymers from Renewable Sources. New Hemicellulose‐Based Hydrogels

Communication: Hemicellulose/poly(2-hydroxyethyl methacrylate) (PHEMA)-based hydrogels were prepared by the radical polymerization of HEMA with hemicellulose purposely modified with well-defined amounts of methacrylic functions using a redox initiator system. Oligomeric hydrosolube hemicelluloses produced from spruce chips were used for modification studies. The chemical modification of hemicellulose was performed with 2-[(1-imidazolyl)formyloxy]ethyl methacrylate as a modifying agent and triethylamine as the catalyst. The kinetics of the modification reaction was monitored by means of H-1 NMR spectroscopy. The resulting hydrogels obtained after a 30 min reaction were homogeneous, elastic, and transparent materials.

Polymers from Renewable Resources

From the point of view of making novel polymers with inherent environment-favorable properties such as renewability and degradability, a series of interesting monomers are found in the metabolisms and cycles of nature. This review presents and discusses a number of aliphatic polyesters which show interesting applications as biomedical materials and degradable packages. Available from nature are amino acids, microbial metabolites from the conversion of glucose and other monosaccharides (e.g., acetic acid, acetone, 2,3-butanediol, butyric acid, isopropanol, propionic acid), lactic acid, ethanol and fatty acids. A series of biodegradable polymers with different properties and different potential industrial uses were made starting with succinic acid and/or 1,3-propanediol. There were two routes for making the polyester-based materials; the direct ring-opening polymerization of lactones (cyclic esters) synthesized from 1,3-propanediol, and the chain-extension of α,ω-dihydroxy-terminated oligomeric polyesters produced by thermal polycondensation of 1,3-propanediol and succinic acid (oligo(propylene succinate)s).

New biodegradable polymers from renewable sources. High molecular weight poly(ester carbonate)s from succinic acid and 1,3‐propanediol

High molecular weight poly(ester carbonate)s have been prepared by a two-step chain-extension reaction performed on oligomeric alpha,omega-dihydroxy-terminated poly(1,3-propylene succinate) in turn obtained by thermal polycondensation of excess 1,3-propanediol with succinic acid. The new polymers have a biodegradable backbone and derive from renewable sources. Therefore, they have a potential as environment-friendly materials.

Multisensor array of mass microbalances for chemical detection based on resonant piezo-layers of screen-printed PZT

Abstract Original mass-microbalance sensors for gravimetric chemical detection are presented which are based on thickness-mode piezoelectric composite resonators made by lead zirconate titanate (PZT) films screen-printed on alumina substrate. By exploiting a cheap and affordable technology, such devices easily enable to manufacture gravimetric multisensor arrays on the same substrate. This is demonstrated by the presented four-sensor array manufactured on a 25×25 mm2 substrate, which also incorporates a thermostating element to minimize thermal drift. The resonators operate around 7 MHz and have a mass sensitivity in the order of 500 Hz/μg. The operating principle and sensor structure is described, and experimental results are reported relative to the sensors covered with purposely prepared polymeric coatings and exposed to hydrocarbon vapours (toluene and hexane) and SO2.

New segmented poly(ester‐urethane)s from renewable resources

The physical and mechanical properties of aliphatic homopolyesters from monomers obtainable from renewable resources, namely, 1,3-propanediol and succinic acid, were improved by their combination with aromatic urethane segments capable of establishing strong intermolecular hydrogen bonds. Segmented poly(ester-urethane)s were synthesized from dihydroxy-terminated oligo(propylene succinate)s chain-extended with 4,4-diisophenylmethane diisocyanate. The newly synthesized materials were exhaustively characterized by 1 H NMR spectroscopy, size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, and with respect to their main static mechanical properties, an Instron apparatus was used. The average repeat number of the hard segments, evaluated by NMR, ranged from 4 to 9, whereas that of the flexible segments was about 14. The degree of crystallinity, glass-transition temperature, melting point, tensile strength, elongation, and Youngs modulus were influenced by the ratio between hard and soft segments of the segmented copolymer in a predictable way. The results demonstrated that poly(ester-urethane)s from 1,3-propanediol and succinic acid are promising thermoplastics.

New ester and lactone end-functionalized N-vinyl-2-pyrrolidinone oligomers

New oligomers of N-vinyl-2-pyrrolidinone functionalized at one end with either ester or lactone functions were obtained by radical polymerization in the presence of different ester (methyl isobutyr ...

Polymeric Hydrogels in Drug Release

.In the present paper we describe the synthesis and characterization of polymeric hydrogels based on HEMA to be used in the formulation of drug delivery systems. In particular HEMA hydrogels were developed to be used as components of dental implants amenable to the controlled release of antibiotics and in the preparation of polymeric scaffolds for tissue engineering application. Studies were carried out to assess a method for loading methronidasole, an antibiotic drug widely used in dentistry, into the hydrogel matrix. Attention was focused on the characterization of samples with different degree of crosslinking and of swelling in various aqueous