This article presents a review on the recent advances in the field of ternary diglycidyl ether of bisphenol A epoxy nanocomposites containing nanoparticles and other modifiers. Particular attention is paid to their mechanical and thermal properties. The properties of epoxy resins were improved by incorporating various single toughening agents, in solid or liquid states. This latter process often resulted in the improvement in some properties at the expense of others. The use of two appropriate modifiers for the preparation of hybrid composites, possibly will show a synergistic effect on the performance properties of the composites. Due to the huge amount of modifiers that were used, the present paper will focus mainly on largely employed nanoclays with modifiers in a liquid and solid state. The former modifier contributes to an increase in the flexibility of the matrix, while the latter modifier is intended to improve other properties of the polymer depending on its structure. Various studies which were carried out on hybrid epoxy nanocomposites confirmed the occurrence of a synergistic effect within the tested performance properties of the epoxy matrix. Nevertheless, there are still ongoing research works using other nanoparticles and other modifiers aiming at enhancing the mechanical and thermal properties of epoxy resins. Despite numerous studies carried out so far to assess the fracture toughness of epoxy hybrid nanocomposites, some problems still remain unresolved. Many research groups are dealing with many aspects of the subject, namely the choice of modifiers and preparation methods, while taking into account the protection of the environment and the use of components from natural resources.

Nanocomposites based on poly(3-hydroxybutyrate) (P3HB) and Cloisite^®30B were prepared by direct mixing in a co-rotating twin-screw micro-extruder. The X-ray diffraction method and transmission electron microscopy allowed to identify the nanostructure. Thermal properties of the obtained nanocomposites were investigated with the use of thermogravimetry (TG) and differential scanning calorimetry (DSC). TG analysis of nanocomposites showed that thermal stability of the obtained nanocomposites was higher by approximately 20 °C than the neat P3HB. The phase transitions such as the glass transition, the crystallization and the melting have been studied by the DSC. The influence of nanofiller’s presence in the polymer matrix on glass transition, crystallization and melting processes of the material obtained was determined and compared with the neat P3HB. The clay addition to the polymer matrix made the increase of the degree of crystallinity and the increase of the degree of amorphous of semi-crystalline P3HB. Furthermore, mechanical properties such as impact strength, flexural strength and hardness were investigated and compared with unfilled P3HB. Obtained nanocomposites containing 1 mass/% of Cloisite^®30B have the best mechanical properties, better than the neat P3HB.

Poly(N-isopropylacrylamide) (PNIPA), as a smart polymer, can be applied for drug delivery systems. This amorphous polymer can be exposed on a structural recovery process during the storage and transport of medicaments. For the physical aging times up to one year, the structural recovery for PNIPA was studied by advanced thermal analysis. The structural recovery process occurred during the storage of amorphous PNIPA below glass transition and could be monitored by the differential scanning calorimetry (DSC). The enthalpy relaxation (recovery) was observed as overshoot in change heat capacity at the glass transition region in the DSC during heating scan. The physical aging of PNIPA was studied isothermally at 400.15 K and also in the non-isothermal conditions. For the first time, the structural recovery process was analyzed in reference to absolute heat capacity and integral enthalpy in frame of their equilibrium solid and liquid PNIPA.

Polyurethanes are widely used polymeric materials; their crosslinked structure and compositional diversity significantly hinder effective end-of-life management. The review emphasizes polyurethane recycling technologies, with chemical aspects discussed only insofar as they directly affect recyclability. The influence of polyol and isocyanate structure on phase separation, network architecture and thermal stability is discussed in the context of degradation and depolymerization mechanisms. Mechanical, chemical, thermochemical and emerging biological recycling routes are compared, with emphasis on their respective advantages, limitations and technological maturity. Mechanical recycling remains the most accessible option on an industrial scale but typically leads to reduced mechanical and thermal-insulation performance. Chemical recycling—particularly glycolysis, hydrolysis and aminolysis—enables partial recovery of polyols suitable for reuse in new polyurethane formulations, albeit at the cost of higher energy demand and increased process complexity. The environmental impact of polyurethane recycling is considered in terms of energy consumption, greenhouse-gas emissions, waste-reduction potential and alignment with circular-economy principles. Emerging biological and hybrid recycling strategies are highlighted as promising low-temperature alternatives with potential environmental benefits, despite their current low technological readiness. Key structural and technological barriers to efficient polyurethane recycling are identified, and future research directions toward improved sustainability and resource efficiency are outlined.

Polyurethane foam materials are the majority among all foam materials. Additionally, they are main part of all produced polyurethanes. Therefore, the problem of selection of suitable blowing agents is very crucial from the point of view of technological, economic and environmental protection benefits. The work is collected and discussed all kinds of physical blowing agents which are used in the production of polyurethane foams. The basic blowing agents used in the polyurethane technology include: chlorofluorocarbons (CFCs), hydrogenated fluorocarbons (HFCs), hydrogenated chlorofluorocarbons (HCFCs), low-boiling saturated and unsaturated hydrocarbons, hydrofluoroethers (HFEs) and carbon dioxide. Issues related to the problem of selecting a suitable foaming agent, taking into account the environmental impacts, foam production costs and the impact on their properties, especially on the heat-insulation, combustibility, have been widely discussed in the work.