Giorgio Giannotta

New polymeric materials for containers manufacture based on PET/PEN copolyesters and blends

Hot-fillable, re-fillable, high oxygen-barrier and high UV-barrier containers cannot be conveniently made with poly(ethylene terephthalate). Copolyesters of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, prepared through either melt-polycondensation or blending, are very promising material for the manufacture of containers with special performances. The properties of these materials depend on their composition and microstructure, which can be tuned by controlling the experimental parameters during their preparation. In particular, the effect on crystallization rate, which plays a key-role in the bottle manufacturing cycle (comprising melt polymerization, solid-state polymerization, drying, molding and blowing), is discussed.

Syndiotactic polystyrene/high-density polyethylene blends compatibilized with SEBS copolymer: thermal, morphological, tensile, dynamic-mechanical, and ultrasonic characterization

A series of syndiotactic polystyrene (sPS)/ high-density polyethylene (HDPE) binary blends were prepared in the melt and then compression molded. Afterwards the blends were characterized by means of DSC, SEM and TEM microscopy, tensile tests, DMTA and acoustic measurements. The morphological, thermal and dynamic-mechanical analyses carried out on the binary blends evidence a clear phase separation between the components at all compositions and a lack of adhesion at the interface, Coherently, tensile texts show no improvement in the toughness of sPS when blended with HDPE. Upon addition of polystyrene-block-poly(ethylene-ranbutylene)-bloch-polystyrene (SEBS) copolymer to the binary blends as compatibilizer, a fine dispersion of HDPE within the sPS matrix and a good adhesion at the imerface is found. Although the good adhesion is confirmed by DMTA, tensile tests reveal no improvement of the mechanical properties of these ternary blends. This result is explained by assuming that the crystaltization of sPS at the interface favors the disentanglement, of poly-styrene end-groups of SEBS out of the sPS domain and therefore a weakening of the interfacial bending strength.

Oxazoline-containing phosphazene derivatives. Part I: the case of hexakis(4-oxazolinophenoxy)cyclophosphazene

In this paper, the synthesis, characterization, and reactivity of a novel oxazoline-containing cyclophosphazene, hexakis(4-oxazolinophenoxy)cyclophosphazene, C-6-OXA, are reported. This product was synthesized by a two-step procedure that required first the preparation of 2-(4-hydroxyphenyl)-2-oxazoline and then the successive treatment of this compound with hexachlorocyclophosphazene in the presence of NaH (60% oil dispersion). The resulting C-6-OXA was eventually reacted with low-molecular-weight organic molecules, e.g. 4-benzoylbenzoic acid, to form highly photosensitive cyclophosphazenes, and with high-molecular-weight polymers, e.g. poly(ethylene terephthalate), PET, acting as a new type of multifunctional, phosphazene-based chain extender, to produce branched PET macromolecules showing greatly modified rheological properties.

Oxazoline-Containing Phosphazene Derivatives, Part III: Synthesis and Characterization of Novel Cyclophosphazenes Functionalized With Chiral 2-Oxazoline Groups

In this paper we describe the synthesis and the characterization of a series of cyclophosphazenes substituted with 2-oxazoline-containing moieties, with and without optical activity. These products could be obtained by reacting cyclophosphazenes containing six (hexachlorocyclophosphazene, C-6-Cl), two (2,2-dichloro-4,4,6,6-bis[spiro(2′,2″-dioxy–1′,1″-biphenyl)]cyclophosphazene, C-2-Cl) and one (pentakis(phenoxy)monochlorocyclophosphazene, C-1-Cl) chlorine atoms, respectively, with a series of 4-hydroxyphenyl-2-oxazolines, as obtained by condensation reaction of methyl-4-hydroxybenzoate with 2-aminoethanol and with chiral and racemic 1-amino-2-propanol, and successive cyclization reactions of the resulting hydroxyamides to 2-oxazoline compounds.

Reactive Cyclophosphazenes Containing Oxazoline Groups: the Case of Hexakis(4-Oxazolinophenoxy)Cyclophosphazene

Hexakis(4-oxazolinophenoxy)cyclophosphazene, a multifunctional cyclophosphazene derivatives containing six pending oxazoline groups, was prepared by reacting hexachlorocyclo-phosphazene with 2-(4-hydroxyphenyl)-2-oxazoline. The resulting trimer was successively treated with carboxylic group-containing molecules (4-benzoyl-benzoic acid) and macromolecules (polyethylene terephthalate) to produce a novel photoinitiator and a polymer having higher molecular weight and improved mechanical properties, respectively.

XPS and DSC Studies of Solution Cast Polystyrene/Poly(organophosphazene) Blends. I. Polystyrene/Poly(phenoxy)phosphazene

Blends of polystyrene (PS) with poly(phenoxy)phosphazene (PPN) were studied by differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). A third component, poly(2,6-dimethyl-1,4-phenylene ether) (PPE), was added with the aim of increasing compatibility of the blends. Tg values did not vary in the PS/PPN blends, indicating that the components are substantially incompatible. The addition of PPE did not change the situation much even though some compatibility between PPN and PPE was detected. XPS on the cast films showed that only PPN was present at the surface. The surface composition of the blends was found to be dependent on the preparation technique.

Hexakis(4-Oxazolinophenoxy) Cyclophosphazene as a Novel Compatibilizer for Polycarbonates and Polyamides

Hexakis(4-oxazolinophenoxy)cyclophosphazene has been used to promote the compatibility between polycarbonate and polyamide-6 polymers. The resulting blends were characterized by a variety of method to assess the occurred compatibilization between the two types of macromolecules.

Molding of syndiotactic polystyrene under its melting temperature

Syndiotactic polystyrene (SPS), a thermoplastic polymer that exhibits a high T m in some crystalline forms, can be conveniently processed by a cold-compaction technique. Processing temperatures in the range of 150-210°C, well below the T m , v gives rise to physicomechanical properties comparable and even better than those obtained by thermal compression or injection molding. The optimum treatment temperature seems to fall around 175°C. X-ray diffraction analysis, thermal analysis, and density measurements suggest that such behavior is connected to phase transitions of SPS and favored by the presence of styrene included in the crystalline fraction.