Aurelia Ioanid

Lignin/epoxy composites

Abstract This paper presents some possibilities for the use of lignin/epoxy resins in blends and composites with epoxy resins. A compatibility study was carried out by optical and electron microscopy, viscosimetric determinations and thermo-optical analysis in order to establish optimum synthesis conditions of molding mass (cast resins). Lignin/epoxy composites including various fillers (lead soap, alum earth, talc, chalk, sand, trihydrate aluminium oxide, glass fibers), plasticizer (dibutylphthalate and polyester C6) and pigments (iron-oxide and titanium dioxide) have been obtained. Lignin/epoxy composites are characterized by good dielectric, mechanical and adhesive properties. These composite materials can be used in the electronics industry.

Polyester/lignosulfonate blends, 2. Accelerated aging behavior

The behavior of the poly(ethylene terephthalate)-co-(ethylene isophthalate)] copolymer/epoxy-modified lignosulfonate (LER) blends has been studied during aging, in the conditions of sewage sludge test. The bulk and surface properties of the aged blends have been followed by electron microscopy, DSC, TG/DTG, IR spectroscopy and contact angle measurements, and compared with undegraded samples. It has been established that the UV-irradiated blends undergo more important changes in their properties after aging than the unirradiated samples. The physical treatment and increase of LER content in the blend could be a way to obtain materials with a good balance of properties and environmental degradation.

Compatibility of polystyrene/polyolefin blends containing compatibilizing agents, 2: Extraction behavior

Polystyrene (PS)/polyolefin (PO) blends in various mixing ratios compatibilized by a triblock copolymer polystyrene-block-poly(ethene-co-butylene)-block-polystyrene (SEBS) and a diblock copolymer polystyrene-block-poly(ethene-co-propene) (SEP) and subsequently Υ-irradiated were prepared. The blends have been subjected to extraction in different solvents (chloroform or toluene) for various periods of time to obtain porous films. The efficiency of the extraction and the morphology of the films have been assessed by infrared spectrometry (IR), optical and electronic microscopy, differential scanning calorimetry (DSC) and thermogravimetry (TG); glass parameters and weight losses have been evaluated. The extraction behavior is close related to compatibility of the components, so on the base of the obtained results optima compatibility ratios have been established. Optical density of the bands corresponding to PS (1955, 1880, 1812, 1610, 1595, 1340, 1195, 1160, 1080, 1040, 995, 975, 912, 850, 555 cm -1 ) in the PS/PP blends (A m ) versus the optical density of the same bands of the pure PS (A p ).