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Poly (vinyl alcohol) composites reinforced with three kinds of papers which differ by voids content were investigated. Paper fibre length distribution was established as well as the structure of cross sections of paper and composites were studied by scanning electron microscope. The denser is a paper, the more loosens its structure after immersion in water and the more decreases its tensile strength after soaking and subsequent drying. The less dense is a paper, the more completely it was filled by polymer and the greater is an increase of strength-deformation characteristics of the composite. The increase of these characteristics is grater in the direction perpendicular to the fiber orientation route. The air permeability of composites and untreated paper as well as character their biodegradation were investigated.

This paper presents and discusses results from LCA studies for the commercially important bio-based polymeric material - poly (lactic acid); petrochemical - low density polyethylene and new packaging material - polyethylene with oxidizing additives. During this study only 2 aspects - the energy used and greenhouse gases exhausted have been studied and calculated for first and second life cycle stage (materials production and processing). Summarized results testify that the greatest negative burden on environment gives oxo-PE, since oxo-additives promotes fragmentation of PE and excludes recycling. Additionally to energy use, another aspect is: metal ions – one of degradation product of oxo-PE - causing the soil contamination and threaten human health. PLA packaging material presents the most appropriate long-term development outcomes considering energy use and greenhouse gas emissions.

Poly (vinyl alcohol) (PVA) and poly (vinyl acetate) (PVAc) blend films were prepared by mixing of water systems: PVA solution and PVAc emulsion with subsequent drying at room temperature. Differential scanning calorimetry (DSC) and SEM investigation shows that components in mixtures form discrete phases. Blends are microheterogeneous. In blends with high PVA content where the dispersion phase is PVA, inclusions of PVAc phase with predominant dimensions 2 - 4 m are detectable. For systems with low PVA content PVA inclusions as discrete objects are less visible. Tensile stress  - strain relations of blend films were determined. Some common  and  values were fixed(maximum stressMAXand respective strain value MAX, yield stressY and correspondingY, and characteristics at fracture Band B), initial modulus of elasticity E = lim(d/d)|→0 . Films with broad range of tensile strength-deformation characteristics: E = 0,3 – 2,2 GPa, MAX = 9 – 106 MPa, Y =: 8 – 73 MPa, B = 11 - 42 MPa, B = 0,32 – 2,07 can be obtained by variation of ratio of component content in mixture

The method of determination of the elastic modulus is based on a solution to the problem of compression of a thin-walled circular cylindrical tube by two parallel planes. The contact problem is solved by the finite-element method (ANSYS). The deformation of a thin polymer shell is characterized by great displacements and relatively low elastic deformations in a large range of movement of parallel planes. This method was employed to calculate the elastic modulus for a series of experimental specimens consisting of five polymer compositions, whose elastic modulus have been found earlier via standard tension tests. The good correspondence between the results confirms the efficiency of the given method.

Purpose of present work is to investigate mechanical and insulation properties of the composite material based on scrap tires and polyurethane-type binder in correlation with composition of composite material. The studies of material’s hardness must be considered as an express-method for estimation of the selected mechanical properties (E and ccompressive stress) of the composite material without direct experimental testing of given parameters. It was shown that composite material must be recommended as insulation material for practical application

This research is devoted to the investigation of the ferrite modified polymer matrix nanocomposites. Auto-combustion route has been utilized for the manufacturing of the ferrite nanoparticles. The effect of initial chemical composition and most important processing parameters on the fineness of the ferrite nanopowder have been cleared out. Obtained ferrite nanoparticles have been introduced in a polycarbonate matrix by melt mixing. Most important technological parameters of the melt processing have been defined. Certain stress-strain, calorimetric and structural properties of the polycarbonate/ferrite nanocomposites has been investigated.

Poliolefīnu līmju-kausējumu izmantošana koka līmēšanai. Tika pārbaudīta uz dažādu termoplastu bāzes iegūtu līmju-kausējumu efektivitāte saplākšņu līmēšanai salīdzinot ar rūpniecisko fenola-formaldehīda līmi. Tika noteikta adhēzija bīdē saplākšņiem, salīmētiem ar dažāda tipa līmēm, pirms un pēc mitruma iedarbības. Konstatēja, ka termoplastu līmes ir salīdzināmas ar tradicionālajām reaktoplastu līmēm gan pēc adhezīvās stiprības, gan mitruma noturības.

Poliolefīnu/koka šķiedras kompozītu adhezīvā stiprības pētījumi. Tika pārbaudīta iespēja izmantot vairākus modificētus un nemodificētus poliolefīnus(PVA,EVAC,PP) kā saplākšņa līmes-kausējumus. Konstatēts, ka ar modificētu PP salīmēta saplākšņa adhezīvā stiprība ir salīdzināma ar rūpnieciskā saplākšņa stiprību, kur kā līme tiek izmantoti fenola-formaldehīda sveķi.

The nanocomposites were prepared by blending styrene-acrylate copolymer solution with dispersed organically modified montmorillonite. Nano-compositions with different filler concentrations were obtained and tested. Influence of organically modified monmorillonite on the tensile stress - strain curves, elastic modulus, strength, elongation at break and the properties of water vapour barrier (permeability, solubility and diffusivity) are investigated.