Bożena Wilbik-Hałgas

This article presents an evaluation of the accelerated aging impact on the structural properties of biodegradable PLA/HAp implants produced using 3D printing technology for use in traumatic bone defect repairs in individual patients. The designed biodegradable implants were sterilized with a radiation dose of 25 ± 0.99% kGy, then exposed to an accelerated aging process. Selected physicomechanical and chemical properties of biodegradable implants were evaluated with FT-IR spectra analyses and DSC. The accelerated aging process, carried out according to the ASTM F 1980:2002 “Standard Guide for Accelerated Aging of Sterile Barrier Systems and Medical Devices”, simulates three years of implant usage. It confirmed the stability of structural, physical and mechanical properties and proved the effectiveness and safety of the implants’ application. The present study was conducted to determine the shelf-life of newly developed biodegradable implants proposed for the treatment of children and adolescents where bone growth still occurs by using accelerated aging methodologies, allowing the assessment of changes in performance that do not result in a negative impact on the safety of the medical device.

This article discusses the important issue of designing textiles for electrostatic discharge (ESD) protection. ESD protective textiles are used to prevent the failure of electronic circuits. They also safeguard human health and life in explosive environments. The textiles are usually made of woven, knitted, or nonwoven fabrics incorporating a grid or strips of conductive fibers within a base material made of cotton, polyester, or blends of these materials. Various testing standards have been developed to evaluate the suitability of textiles for ESD protection. One of the most widely used is the EN 1149-3 standard, which outlines procedures for recording charge decay plots. The procedure can be used to evaluate all types of textiles. This paper discusses models corresponding to the standard developed in the general-purpose COMSOL Multiphysics software. Using the advanced numerical methods of the software, it is possible to graphically present the phenomena occurring during the application of the standard procedure and to determine the influence of the grid and material parameters on the shape of the charge decay plots. Furthermore, this article compares charge decay plots and shielding effectiveness measured in an accredited laboratory with simulation results.

The paper considers an important problem of designing ESD protective fabrics. Accurate models of the fabrics containing a mesh of conductive threads were developed in general-purpose COMSOL Multiphysics® software. Then model simplifications were made and lumped- element circuit models were proposed. The circuit models were used in a numerical method for fitting weft and warp thread parameters to the desired values of surface and vertical resistance of the fabrics.

The Arrhenius method was used to investigate the effect of accelerated aging conditions on the physical and mechanical properties of polymer films for technical, medical, food and office applications. Temperature and UV radiation were taken into account as environmental factors. It was shown that the tested films are more sensitive to thermal degradation than UV radiation. The reduction in tensile strength after thermal aging does not exceed 40%, and in the case of UV radiation, 14%. The estimated lifetime of the tested films is over 5 years.

Textiles require finishing to improve their usability and functionality but in the first place, to reduce of pilling tendency, which affects all kinds of synthetic and natural fabrics. Several laser ablation tests have been applied to the selected fabrics with different chemical composition to reveal the impact of this process on the pilling behavior. To reflect the pilling changes, two textural descriptors have been proposed to textile images obtained with optical coherence tomography (OCT). They showed the trend to reduce values with increasing laser power applied to the tested fabrics. It has been demonstrated, that in the case of textiles based on polyester threads, laser modification of the product surface led to a significant reduction in their tendency for pilling.

A comprehensive study was performed using the Plasma Assisted Chemical Vapour Deposition (PACVD) modification of ultrahigh molecular weight polyethylene (UHMWPE) fibrous composites and paramid fabrics with the deposition of fluoro-or silane-like-polymer onto their surface. Research on the resistance to fragments was performed on the basis of our own testing procedure elaborated on the basis of the STANAG 2920 Ballistic Test Method For Personal Armour Materials And Combat Clothing, revision 2. The model insert systems made of the modified or unmodified unwoven sheets of UHMWPE fibres exhibited significantly different trends of changes in fragment-proofness when the temperature together with humidity were applied as the ageing factors. In the inserts made of modified unwoven sheets, an increase in the V50 value was observed, while the V50 of the inserts made of unmodified sheets decreased along with the extension of the accelerated ageing process. Modification with low-temperature plasma in the presence of vapours of low-molecular fluorine- or silane-genic substrates altered the properties of the fabrics and unwoven sheets. PACVD modification allows to prevent the destructive influence of humidity during the aging process.

The process of textile modification using Plasma Assisted Chemical Vapour Deposition (PACVD) results in significant changes in surface properties with high effectivity. However, the main problem of the above-mentioned modification is to obtain a stable modification effect during standard use and storage. The aim of the study was to determine the stability of structural properties of PACVD-modified para-aramid ballistic woven fabrics during accelerated ageing using temperature or simultaneously temperature and humidity as the accelerated ageing factors. For identification of potential changes in the textile surface modified by PACVD with deposition of the polymer formed based on tetradecafluorohexane, the ATR-FTIR and SEM/EDS techniques were applied. The PACVD-modified textiles showed insignificant changes in structural properties after accelerated ageing using the above-men -tioned ageing factors. This confirms the stability of the PACVD-resulted modification during simulated conditions of standard use.

Designing medical devices requires a wide range of verification steps for estimation of the performance and safety. Designing the research program needs a rational selection of appropriate testing methods (in preclinical and clinical studies) for determination of the risk of potential incompatibilities resulting in adverse events. The significance of the appropriate selection of the testing method is increased in advanced medical devices. The presented research considers the verification of the functional properties of recently developed topical haemostatic agents with the use of the chitosan/alginate fibrids, based on the previously elaborated risk analysis made according to the guidelines of the PN-EN-ISO 14971:2012 and PN-EN ISO 22442-1:2008 standards. The aim of this research was to verify the stability of the performance of the newly developed haemostatic agents during storage. The defined aim of the study arose from the thesis that the appropriate selection of raw materials and a new manner of reprocessing them enabled keeping the usability of the final product for at least two years.