In this study, hydrophilic based bioactive nanofibers were produced via an electrospinning and electrospraying simultaneous process. Poly(vinyl alcohol) (PVA), poly(vinyl alcohol)-gelatin (PVA-Gel), and poly(vinyl alcohol)-alginate (PVA-Alg) polymers were used as the matrix material and folic acid (FA) particles were dispersed simultaneously on the surface of the nanofibers. The morphology of the nanofibers (NFs) was uniform and confirmed by scanning electron microscopy. Thermal behavior, chemical structure of the composite nanofibers were investigated by thermogravimetric analysis, and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy which showed that no chemical bonding between vitamin and polymers. A fast release of FA-loaded electrospun fibers was carried out by UV-Vis in vitro study within the 8 hour-period in artificial sweat solutions (pH 5.44). The obtained PVA/FA, PVA-Gel/FA, and PVA-Alg/FA fibers released 49.6%, 69.55%, and 50.88% of the sprayed FA in 8 h, indicating the influence of polymer matrix and polymer-drug interactions, on its release from the polymer matrix. Moreover, biocompatibility of all developed novel NFs was assessed by two different cytotoxicity tests, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and neutral red uptake (NRU) assay in L929 (mouse fibroblasts) cell lines. In all cases, it is concluded that these new electrospun fibers had fast-release of the vitamin and the hybrid process is suitable for transdermal patch applications, especially for skin-care products. The results of cytocompatibility assays on L929 reveal that all prepared NFs have no or slight cell toxicity. PVA and PVA-Gel with/without FA nanofibers seems more biocompatible than PVA-Alg nanofibers.

In this study, bioactive fibers were produced using polyvinyl alcohol (PVA), gelatin, polyvinyl pyrolidone (PVP) as a polymer matrix and different amounts of folic acid (FA) as an vitamin by using electrospinning method. Loading of the folic acid in the polymers was determined by the Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), morphologies and average diameters were analyzed by Scanning Electron Microscopy (SEM) and Thermal Gravimetric Analysis (TGA) was applied for determining thermal behaviors.The FTIR spectra TGA showed the successful incorporation of folic acid to the fibers. SEM images showed that various smooth and heterogenous electrospun fibers were produced with average diameters ranging from 125 nm to 980 nm. In vitro study was carried out by using FA dissolved in artificial sweat solution (acidic media, pH 5.44) and UV-Vis analysis of electrospun fibers were evaluated. In vitro release studies showed the FA loaded nanofibers had initial vitamin burst release behavior. The maximum vitamin release percentage of PVA/FA, gelatin/FA and PVP/FA fibers was obtained 86.88 %, 80.2 % and 76.66 %, respectively. From these results, the FA-loaded fibers are potential candidates for transdermal patches and topical applications.

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The fabrication of skin-care products with therapeutic properties has been significant for human health trends. In this study, we developed efficient hydrophilic composite nanofibers (NFs) loaded with the folic acid (FA) by electrospinning and electrospraying processes for tissue engineering or wound healing cosmetic applications. The morphological, chemical and thermal characteristics, in vitro release properties, and cytocompatibility of the resulting composite fibers with the same amount of folic acid were analyzed. The SEM micrographs indicate that the obtained nanofibers were in the nanometer range, with an average fiber diameter of 75–270 nm and a good porosity ratio (34–55%). The TGA curves show that FA inhibits the degradation of the polymer and acts as an antioxidant at high temperatures. More physical interaction between FA and matrices has been shown to occur in the electrospray process than in the electrospinning process. A UV-Vis in vitro study of FA-loaded electrospun fibers for 8 h in artificial acidic (pH 5.44) and alkaline (pH 8.04) sweat solutions exhibited a rapid release of FA-loaded electrospun fibers, showing the effect of polymer matrix–FA interactions and fabrication processes on their release from the nanofibers. PVA-CHi/FA webs have the highest release value, with 95.2% in alkaline media. In acidic media, the highest release (92%) occurred on the PVA-Gel–CHi/sFA sample, and this followed first-order and Korsmeyer–Peppas kinetic models. Further, the L929 cytocompatibility assay results pointed out that all NFs (with/without FA) generated had no cell toxicity; on the contrary, the FA in the fibers facilitates cell growth. Therefore, the nanofibers are a potential candidate material in skin-care and tissue engineering applications.

The slippage-based opening at the seam line occurs on the woven fabrics due to movement in the fabric of the weft yarns over warp yarns (or warp yarns over weft yarns) at a sewn seam during utilization. Recurrent sitting down and standing up or continuously sitting down produces a load at the seam line and causes transverse strain at stitch rows. Owing to this strain, displacement (seam slippage) of the stitch could occur, leading to opening in the fabric at the seam line. This study is focused on constructing a system which is based on a non-linear regression mathematical model to predict the seam opening properties of woven fabric within two different seam opening standard test methods. The first is the fixed load test method; the other is dynamic seam fatigue. The physical properties of the fabric and stitch density play important roles in the seam opening of the seat fabric. The number of weft yarns per unit length, yarn linear density and stitch density were selected as influential factors. The prediction equation is based on completely randomized variance analyses model. The coefficients of the curves fitted were computed by means of non-linear regression analysis. Regression coefficient ( R2) values for these curves were observed to be highly reliable at more than 0.9. Also the correlation coefficients ( r) between actual and predicted values were very high at more than 0.96.

An hydroxyl‐terminated quaternary ammonium salt polymer (QAP) was added to a foam formulation in various amounts between 1 and 5 wt %. The structures of the produced foams and their QAP content were characterized by Fourier transform infrared and EDXRF analyses. A linear polymer of QAP with a diisocyanate was also synthesized to support our investigations. The morphological changes such as the cell size and the cell structure of the produced foams were observed with scanning electron microscopy. Thermogravimetric analysis and dynamic mechanical analysis analyses were applied to examine the thermal and thermomechanical properties of the produced foams. Relatively low amount of QAP‐added foams showed very similar structural and thermomechanical properties to the unmodified foams. In addition, while the unmodified foams did not show any antimicrobial activity, the QAP‐added foams provided significant inactivation against Staphylococcus aureus, yeast and mold at concentrations of about 102 and 103 CFU within 5 h of contact time. The results showed that the addition of minute amount of QAP can significantly improve the biocidal performance of the produced foams without deteriorating their structure. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45914.

The most popular method to produce composites for ballistic applications is to use aramid and ultra high molecular weight polyethylene (UHMWPE) fibers as reinforcement materials in different matrices. The composite materials used in this type of application, especially those used as armoring materials for explosions, are subjected to a very high level of energy. In this study, the effect of the reinforcement material type and cross-plied condition of reinforcement were examined using high-level impact tests. The impact tests were performed at low speed but high energy, and thus the behaviour of the composite materials that were exposed to high-level impact energy could be examined. According to the results, the UD aramid composite produced the best results with respect to high-level impact tests. In addition, mass optimisation could be achieved without the loss of the high-level impact energy by preparing a hybrid composite with UD UHMWPE and UD aramid fibers.

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