- Eco-friendly polymers for food packaging, green building and coating applications
- Synthesis and characterization of novel polymeric
materials for biomedical applications.
- Study of polymer crystallization
- Complex analyses of dynamic phenomena and of
polymeric material structure
- Preparation and characterization of "Eco-friendly nanocomposites" for food packaging and biomedical applications.
- Synthesis and characterization of novel S-S containing polyesters.
Eco-friendly polymers for food packaging, green building
and coating applications
This research field is mainly focused on the synthesis and
characterization of novel biodegradable polymers and copolymers
which offer physicochemical properties suitable for the desired
application. An alternative approach consist in the chemical
modification of commercially available polymers to make them
attractive for different uses.
Regardless of the synthetic approach adopted, the main goal is
to find out structure-properties relationships of main interest for
designing a material which completely fits the requested
specifications. As an example, green food packaging materials must
accomplish basic requirements to be an ideal candidate for food,
which includes barrier properties (water vapor, gases, light and
aroma), optical properties (transparency), strength, welding and
molding properties, disposal requirements, antistatic properties
and, above all, strictly follow food safety.
Copolymerization as well as physical and/or reactive blending
approach are an effective way of achieving a deliverable
combination of properties, which are often absent in single
component polymers. Moreover, the final properties of the material
can be favorably modified, depending on the kind, relative amount,
distribution and architecture of the comonomeric units or, in the
case of mixture, by properly varying the homopolymers and blend
composition. The choice of the monomers to be used in the
polymerization process as well as of the comonomeric unit to be
introduced along the polymeric chain of the parent homopolymer will
be made on the basis of the requirements that the materials have to
The so synthesized polymers are fully and deeply characterized
both using the technology available in the DICAM labs and through
collaborations with other research groups.
Polymeric materials for biomedical
As it is well known, polymers are the most versatile class of
materials, thus can be favorably designed to fulfill the needs
related to the variety of tissues and diseases involved in the
human body. The research group has recently focused its activities
on two main aspects of biomedical engineering: tissue
engineering, controlled drug release and polymers with
Tissue engineering The control of molecular structure
and tridimensional architecture of synthetic polymeric constructs
(scaffolds) - designed to reproduce the typical properties of the
damage tissue - is a key element for controlling cell adhesion,
proliferation, migration and differentiation. In the field of
tissue engineering the possibility to employ scaffolds mimicking
native tissue is limited by the scarce availability of
biocompatible and biodegradable polymers with proper mechanical
properties, especially in terms of stiffness.
Controlled drug release Classical methods of drug
delivery exhibit specific problems that scientists are attempting
to address. The goal of new drug delivery systems, therefore, is to
deliver medications intact to specifically targeted parts of the
body and to release them in a controlled way depending on the
required treatment regime. The design of the drug carrier is
fundamental in order to achieve the correct tissutal and cellular
localization of drug molecules and perform an adequate release. In
this framework, polymers and copolymers are the most promising tool
to obtain materials showing specifically designed properties to be
employed as drug carriers.
Investigation of polymer crystallization
It is well known that crystallization is a phase transition that
plays an important role in determining the morphology of a polymer
for a wide range of technological processes, in which commodities
are formed from synthetic plastics. Therefore, studies of the
isothermal crystallization of polymers commonly have been used to
investigate the specific mechanisms of the crystallization process
and from a technical standpoint are relevant to optimizing process
conditions. In fact, the morphological structure (size, shape,
perfection, orientation of crystallites), which is formed by
crystallization from the molten state, influences strongly most of
the physical and mechanical properties of polymeric products.
Moreover, because the crystal structure and morphology (the crystal
habit and organization of crystals into aggregates of a higher
order) are responsible for many properties of the final products,
knowledge of the crystallization mechanism is crucial for designing
materials with the required properties. The crystallization
kinetics are investigated by DSC and hot-stage optical microscopy
(MO), both available at the laboratories of the Department. MO
technique, beside measuring spherulitic growth rate, allows to
obtain information on crystal phase morphology, which changes with
undercooling degree and therefore with Tc. Both melt isothermal and
non-isothermal crystallization kinetics studies are carried out.
Melt isothermal crystallization kinetics is investigated by DSC
technique and the data analyzed according to the Avrami's
treatment, which allows the calculation of kinetic constant of
crystallization process. On the contrary, the data obtained from
measurements carried out under non-isothermal conditions are
analyzed according Tobin and Ozawa equations. The crystallization
process is also investigated employing equipments located at other
research laboratories, such as: XRD, AFM and DETA. Lastly,
crystallization rate is correlated with polymer chemical structure,
to establish structure-property relationship, which are
fundamental to design a new material with â€œad hocâ€ properties.
For copolymers, crystallization parameters are correlated with
copolymer composition (random copolymers) and with molecular
architecture, i.e. crystallisable block length (block
Complex analyses of
dynamic processes and of polymeric material
As is well known, molecular motions of amorphous macromolecular
chains are deeply affected by sample crystallinty degree because
amorphous macromolecular segments have to relax among crystalline
regions at temperatures above glass transition temperature. Such
constraints significantly influences energy dissipation mechanism.
As a consequence, some important physical properties, such as
mechanical ones, are affected by crystallinty degree. Aim of such
researches is therefore to establish correlation between molecular
motions, investigated by means of dielectric spectroscopy, and
system order degree, evaluated by X-ray measurements. Such
correlations are indeed crucial to optimize the physical properties
of a material. Such studies are carried out in collaboration with
Reserch Group of prof. Ezquerra (CSIC-Madrid).
Preparation and characterization of "Eco-friendly nanocomposites" for food packaging and biomedical applications.
The skills developed by the research group in the field of polymeric composites and nanocomposites arise from the specific needs for high-performance materials, characterized by highly specific properties and by low environmental impact. The applications of these materials are wide in fact, depending on the type of nanofiller employed, they are characterized by high mechanical performance, heat resistance, reduced gas permeability and flammability and by specificic properties, such as conduction, optical, antibacterial and photo-catalytic properties. In all cases, in order to obtain the best possible performance of the final material, the main parameters that are developed and optimized are the physicochemical properties of the inorganic phase, such as the surface area, the morphology, the particle size, the interaction with the polymer chains and their functional groups, but also the degree of dispersion and adhesion at the interface with the matrix, which play a crucial role and can be controlled by acting on the chemical modification of fillers and on the techniques used for their mixing with the matrix. the nanoparticles are dispersed by melt mixing using Brabender or co-rotating twin-screw extruders. Moreover, in the field of nanocomposite materials research has focused on the preparation of materials based on poly (butylene succinate) (PBS), which constitutes one of the most emerging biopolymers. Currently the application of this polyester is limited due to the high production costs and reduced mechanical and gas barrier properties. To solve these issues nanocomposites with nanocellulosic fibers have been prepared. Excellent results in terms of adhesion at the interface and mechanical properties were obtained without chemically altering the fibers and then developing a final material completely "bio".