In this paper the influence of calender temperature on the crystallization behavior of polylactide (PLA) non-woven fabrics during their manufacturing by the spun-bonding technique is described. Non-woven samples were studied by wide-angle X-ray diffraction, differential scanning calorimetry and birefringence. In addition, physical–mechanical properties of the non-woven fabrics were determined. The results are discussed in terms of structural changes of PLA and meso-phase content during the calendering process in the temperature range 70–130℃. The rebuilding of the supermolecular structure of the investigated samples of PLA fabrics under the influence of increasing calender temperature is observed in terms of the disorder-to-order phase transition (ά to α form) during heating around 110℃, and increased degree of crystallinity up to 100℃. The presented structural rebuild of PLA explains observed changes of physical–mechanical properties of the non-woven fabrics obtained at different calendering temperatures. During calendering above 100℃, thermal degradation of PLA occurs at the point of contact between the non-woven fabrics and the calender rollers.

Plastic products, especially in the packaging industry, have become the main commodities penetrating virtually every aspect of our lives. Unfortunately, their omnipresence is not neutral to the natural environment. Pollution in the form of microplastics is a global problem. Therefore, green technologies that enter into the circular economy become an important topic. As part of the research work, the modification of poly(lactic acid) has been studied for use in the packaging industry. Due to its intrinsic rigidity, plasticizing substances had to be introduced in PLA in order to improve its plastic deformability. Both high-molecular compounds such as ethoxylated lauryl alcohol, block copolymer of ethylene oxide and propylene oxide, and ethoxylated stearic acid as well as low-molecular compounds such as di-2-ethylhexyl adipate, di-2-ethylhexyl sebacate, and triethyl citrate were used. The samples extruded from plasticized polymers were characterized using differential scanning calorimetry, thermal gravimetric analysis, and mechanical properties including Young’s modulus. The melt flow rate (MFR) and molar mass distribution were determined. For all modified samples the glass transition temperature, depending on the plasticizer used, was shifted towards lower values compared to the base polymer. The best result was obtained for di-2-ethylhexyl adipate (ADO) and di-2-ethylhexyl sebacate (SDO). The elongation at break increased significantly for ADO at about 21%. The highest elongation was obtained for SDO (about 35%), although it obtained a higher glass temperature. The degradation of the polymer was not observed for both plasticizers. For these plasticizers (ADO and SDO) it also lowered Young’s module by about 26%, and at the infrared spectrum deformation of peaks were observed, which may indicate the interaction of the ester carbonyl group of PLA with plasticizers. Therefore it can be concluded that they are good modifiers. The selected plasticizers that are used in the production of food contact materials, in particular in the production of PVC (polyvinyl chloride) food films, also exhibited great potential to be applied to PLA food films, and exhibit better properties than the citrate, which are indicated in many publications as PLA plasticizers.

In this paper, the influence of the take-up velocity (V t-u ) of fibers on the molecular ordering and -form transition of polylactide (PLA) non-woven fabrics during their manufacturing by spun-bonding is described. Non-woven samples were studied by wide-angle X-ray diffraction, differential scanning calorimetry and Fourier transform infrared spectroscopy. In addition, the physical and mechanical properties of the non-woven fabrics were determined. The results are discussed in terms of the structural changes of the PLA and the meso-phase content during the spun-bonded non-woven fabric forming process. This technological process includes preliminary molecular ordering of the PLA fibers in a downstream spinning block and crystallization on a calender system at a temperature higher than the glass transition. The molecular ordering of the investigated PLA fabric samples under different technological conditions was observed as follows: creation of the meso-phase and a disorder-to-order phase transition ( to form) during heating to approximately 110 C and an increase in the degree of crystallinity for take-up velocities higher than 1400 m/min. The structural changes of the PLA explain the observed changes in the physical and mechanical properties of the non-woven fabrics obtained under different technological conditions.

The main challenge of the economy is counteracting the adverse effects of progressive industrialisation on the environment around the world. Economic development that accompanies this trend correlates to production increase in not only consumer articles but also special application articles that are difficult to remanufacture, such as medical supplies. For many researchers, discovering innovative materials for special applications that could become an essential element of circular economy production is important. Measures to reduce the production of industrial materials whose waste is difficult to recycle are more and more apparent to manufacturers, especially when faced with the new financial situation in European Union, as one of its priorities is to implement the principles of circular economy. The purpose of the article is to analyse the current state of research on special-application biomaterials within the context of the circular economy. Empirical analysis is conducted for Poland compared to the rest of the European Union (EU) within the time-frame of 2014–2020, which is the most recent financial timeframe of the EU. The submitted studies are based on secondary data obtained mainly from European databases, as well as primary data resulting from the research works at Łukasiewicz Research Network—Institute of Biopolymers and Chemical Fibres.