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The use of plastic film substrates for organic electronic devices promises to enable new applications, such as flexible displays. Plastic substrates have several distinct advantages, such as ruggedness, robustness, ultra lightness, conformability and impact resistance over glass substrates, which are primarily used in flat panel displays (FPDs) today. However, high transparency, proper surface roughness, low gas permeability and high transparent electrode conductivity of the plastic substrate are required for commercial applications. Polyesters, both amorphous and semicrystalline, are a promising class of commercial polymer for optoelectronic applications. Surface modification of polyester films was performed via chemical solution determining hydrolysis or oxidation. Hydrolysis was carried out by means of sodium hydroxide solution and oxidation by using standard clean 1 (SC-1) of RCA procedure [1]. For this work we have used commercial polymer films of 100 µm in thickness: AryLite™ [2], supplied by Ferrania Imaging Technologies S.p.A. and characterised by very high glass transition temperature, Mylar™ (Polyethylene Terephthalate PET) and Teonex™ (Polyethylene Naphthalate PEN) both supplied by Dupont. Moreover, a bioriented and semicrystalline PET have been used. The aim of this study is modifying the polymer surface to improve the adhesion between organic-inorganic layer. It was found that the NaOH and SC-1 treatment cause a decrease of contact angles. In the present study we have deposited a thin films of amorphous hydrogenated silicon (a-Si:H) and its oxide (SiO2) on a new high temperature polymer substrate, AryLite™, by plasma enhanced chemical vapour deposition (PECVD) [3], with a radio frequency plasma system.

The introduction of thermo-reversible covalent bonds in the molecular network is a recent approach to prepare self-healing polymers upon a suitable thermal trigger. Among reversible reactions, Diels-Alder (D-A) cycloaddition is an ideal candidate for the synthesis of mendable polymers, such as epoxy resins, with improved operative life. The D-A adduct, referred to as 2Ph2Epo, was synthetized and crosslinked with a mixture of aliphatic and aromatic amines. The resin formulation aimed at reaching a compromise between the mending capability of cured material and its dimensional stability at high temperatures, required during healing cycles. The latter result was achieved by mixing the adduct with commercial DGEBA monomer. The ability of the adduct to give direct D-A and reverse D-A (r D-A) has been verified by FT-IR and rheological analysis on 2Ph2Epo. Mechanical tests were performed for assessing the self-healing efficiency of the crosslinked 2Ph2Epo/DGEBA system. The multiple healing feature of the system was proved. The hybrid epoxy resin is able to recover damages, still exhibiting the pristine stiffness, while the strength of the system decreases after progressing healing cycles., INTRODUCTION Biomimetic materials are attracting considerable attention, owing to their ability to mimic the structural, mechanical, and biological properties of natural tissues. The ability to recover material properties after failure [...]

Water sorption tests have been carried out for a novel epoxy resin having liquid crystalline character. The sorption isotherm, relative to the epoxy resin cured in the nematic phase, does not indicate any substantial difference from the resin cured in the isotropic state. This is an indication that, as far as this class of thermosets is considered, the liquid crystalline order does not affect mechanism and equilibrium values of water uptake., INTRODUCTION Epoxy resins are widely used as glassy matrices for structural composites. Since these materials are used at different temperature and humidity conditions, knowledge of the polymer structure parameters affecting [...]

Byline: C. Carfagna, E. Amendola, L. Nicolais The increasing demand of the high technology market for new applications in the aerospace industry has led to research on high performance thermoplastics as composite matrices. The inclusion of solid fibres in this class of materials during manufacturing may result in processing conditions that are too demanding. High temperature and pressure in stamping or injecting tools may result in thermal degradation of the organic matrix. Moreover, the load transfer through the fibre-matrix interface produces fibres breaking into fragments shorter than the critical length, affecting their aspect ratio, and consequently reducing the final performance of the product. The possibility of producing the reinforcing filler during the cooling cycle of the composite processing has suggested the definition of 'in situ' composite. In this paper the addition of thermotropic liquid crystalline polymer to engineering thermoplastics has been investigated. X-ray diffraction techniques have been used to evaluate the molecular orientation of the dispersed phase. The rheology and the mechanical properties of the in situ composites is related to the morphology of the material and to the processing operations.