Wet Relaxation of Electrospun Nanofiber Mats

Electrospinning can be used to produce nanofiber mats. One of the often used polymers for electrospinning is polyacrylonitrile (PAN), especially for the production of carbon nanofibers, but also for a diverse number of other applications. For some of these applications—e.g., creation of nano-filters—the dimensional stability of the nanofiber mats is crucial. While relaxation processes—especially dry, wet and washing relaxation—are well-known and often investigated for knitted fabrics, the dimensional stability of nanofiber mats has not yet been investigated. Here we report on the wet relaxation of PAN nanofiber mats, which are dependent on spinning and solution parameters such as: voltage, electrode distance, nanofiber mat thickness, and solid content in the solution. Our results show that wet relaxation has a significant effect on the samples, resulting in a dimensional change that has to be taken into account for nanofiber mats in wet applications. While the first and second soaking in pure water resulted in an increase of the nanofiber mat area up to approximately 5%, the dried sample, after the second soaking, conversely showed an area reduced by a maximum of 5%. For soaking in soap water, small areal decreases between approximately 1–4% were measured.

Download Full-text

Effects of the Laundering Process on Dimensional and Physical Properties of Plain and Lacoste Fabrics Made from Modal/combed Cotton Blended Yarns

Fibres and Textiles in Eastern Europe ◽

10.5604/01.3001.0010.2667 ◽

2017 ◽

Vol 25 (0) ◽

pp. 75-81 ◽

Cited By ~ 3

Author(s):

Ebru Çoruh

Keyword(s):

Physical Properties ◽

Dimensional Stability ◽

Unit Area ◽

Dimensional Change ◽

Air Permeability ◽

Knitted Fabrics ◽

Bursting Strength ◽

Expert Analysis ◽

Fabric Weight ◽

Loose Medium

In this study, dimensional and some physical properties of plain (single jersey) and lacoste knitted fabrics made from 50/50 modal/combed cotton blended yarns (tex 21 and 15) were investigated. Twelve weft knitted fabrics were produced with two different structures and three different densities (loose, medium, tight). For physical properties, the fabric weight per unit area, fabric thickness, bursting strength, air permeability and dimensional stability were evaluated. We focused on the dimensional stability properties of outwear knitted fabrics. The total dimensional change of the fabric’s dimensions and structural properties were measured and evaluated after ten washing cycles and then flat dried. The results show that the weight per unit area, thickness, air permeability and dimensional stability values are independent of the yarn linear density, fabric structure and fabric density. Statistically evaluated using Design Expert Analysis of variance (ANOVA) software 6.06., test results show that dimensional stability is mostly effective for the bursting strength, air permeability and fabric weight per unit area.

Download Full-text

Impact of Repeated Home Laundering on the Cyclic Deformation Performance of Elastane Knitted Sportswear Fabrics

Fibres and Textiles in Eastern Europe ◽

10.5604/01.3001.0012.7513 ◽

2019 ◽

Vol 27 (1(133)) ◽

pp. 91-99

Author(s):

Vildan Sülar ◽

Eren Oner

Keyword(s):

Dimensional Stability ◽

Cyclic Deformation ◽

Recovery Time ◽

Unit Area ◽

Residual Deformation ◽

Dimensional Change ◽

Test Method ◽

Knitted Fabrics ◽

Minimum Deformation ◽

Time Periods

After washing cycles, textiles having minimum deformation, maximum dimensional stability and the same performance of an unused product are major expectations of customers. This study examined the effects of washing cycles on the cyclic deformation of elastane knitted fabrics in detail. 12 knitted fabrics with two different linear densities of viscose yarn and three different polyamide/elastane gimped yarn of two different tightness levels (normal and tight) were used in the experiments. M&S P15A test method were used to evaluate the cyclic deformation of unwashed and washed fabrics (0, 5, 15 and 25 cycles) for four different recovery time periods (0 min, 2 min, 30 min and 24 h). Dimensional change, tightness factor and mass per unit area values were also examined in order to investigate the residual deformation of the fabrics after each washing stages. Consequently, it is determined that the fabrics having 21 tex viscose ground yarn and 78dtex20f elastane gimped yarn with higher setting show less residual extension (%). 5 and 15 washing cycles and a 30 min. recovery time are found significant for all repeated washings.

Download Full-text

Comparative Study of Pleurotus ostreatus Mushroom Grown on Modified PAN Nanofiber Mats

Nanomaterials ◽

10.3390/nano9030475 ◽

2019 ◽

Vol 9 (3) ◽

pp. 475 ◽

Cited By ~ 9

Author(s):

Lilia Sabantina ◽

Franziska Kinzel ◽

Thomas Hauser ◽

Astrid Többer ◽

Michaela Klöcker ◽

...

Keyword(s):

Comparative Study ◽

Growth Rates ◽

Pleurotus Ostreatus ◽

Edible Mushroom ◽

Fungal Mycelium ◽

Specific Substrate ◽

Biotechnological Applications ◽

Mushroom Species ◽

Nanofiber Mats ◽

Pan Nanofiber

Pleurotus ostreatus is a well-known edible mushroom species which shows fast growth. The fungus can be used for medical, nutritional, filter, or packaging purposes. In this study, cultivation experiments were carried out with Pleurotus ostreatus growing on polyacrylonitrile (PAN) nanofiber mats in the presence of saccharose and Lutrol F68. The aim of this study was to find out whether modified PAN nanofiber mats are well suited for the growth of fungal mycelium, to increase growth rates and to affect mycelium fiber morphologies. Our results show that Pleurotus ostreatus mycelium grows on nanofiber mats in different morphologies, depending on the specific substrate, and can be used to produce a composite from fungal mycelium and nanofiber mats for biomedical and biotechnological applications.

Download Full-text

Dynamic moisture sorption and dimensional stability of furfurylated wood with low lignin content

Holzforschung ◽

10.1515/hf-2019-0033 ◽

2019 ◽

Vol 74 (1) ◽

pp. 68-76

Author(s):

Tiantian Yang ◽

Erni Ma ◽

Jinzhen Cao

Keyword(s):

Relative Humidity ◽

Dimensional Stability ◽

Furfuryl Alcohol ◽

Lignin Content ◽

Moisture Sorption ◽

Dimensional Change ◽

Poplar Wood ◽

Sorption Coefficient ◽

Dimensional Changes ◽

Sinusoidal Shape

AbstractDegradation of lignin occurs naturally in wood due to the influence of microorganisms or photic radiation. To improve the properties of wood with low lignin content, furfuryl alcohol (FA) at the concentration of 25% was used to modify poplar wood (Populus euramericana Cv.) after partial delignification. Moisture sorption and dimensional stability of the samples were investigated under dynamic conditions where the relative humidity (RH) was changed sinusoidally between 45% and 75% at 25°C. Both the moisture content (MC) and the tangential dimensional change varied with a sinusoidal shape similar to the RH. Hygroscopicity and hygroexpansion increased after delignification, while furfurylation led to an inverse impact by reducing MC, dimensional changes, amplitudes of MC and dimensional changes, moisture sorption coefficient (MSC), and humidity expansion coefficient (HEC). After delignification and further furfurylation, the MC and the dimensional changes were reduced by about 20%, and the maximum drop in amplitudes of MC and dimensional changes was about 30%, while the MSC and the HEC decreased by over 15%. In addition, the furfurylated wood with low lignin content exhibited lower sorption hysteresis and swelling hysteresis.

Download Full-text

Self-assembly of various silver nanocrystals on PmPD/PAN nanofibers as a high-performance 3D SERS substrate

The Analyst ◽

10.1039/c5an00716j ◽

2015 ◽

Vol 140 (16) ◽

pp. 5707-5715 ◽

Cited By ~ 10

Author(s):

Peng Jia ◽

Bing Cao ◽

Jianqiang Wang ◽

Jin Qu ◽

Yuxuan Liu ◽

...

Keyword(s):

Self Assembly ◽

High Performance ◽

Sers Substrate ◽

Sers Substrates ◽

Highly Sensitive ◽

Nanofiber Mats ◽

Pan Nanofiber

The AgNCs (AgNPs, AgNTs and AgNDs) decorated-PmPD/PAN nanofiber mats were obtained as highly sensitive 3D SERS substrates.

Download Full-text

Thermal modification of Southern pine combined with wax emulsion preimpregnation: effect on hydrophobicity and dimensional stability

Holzforschung ◽

10.1515/hf-2014-0106 ◽

2015 ◽

Vol 69 (4) ◽

pp. 405-413 ◽

Cited By ~ 24

Author(s):

Wang Wang ◽

Yuan Zhu ◽

Jinzhen Cao ◽

Xi Guo

Keyword(s):

Water Absorption ◽

Dimensional Stability ◽

Photoelectron Spectroscopy ◽

Water Repellency ◽

Solid Content ◽

Thermal Modification ◽

Paraffin Wax ◽

Southern Pine ◽

Thermally Modified Wood ◽

Modified Wood

Abstract The aim of this study was to enhance the water repellency and dimensional stability of thermally modified wood by combining the preimpregnation of paraffin wax emulsion. To achieve this, Southern pine (SP; Pinus spp.) samples were first impregnated with paraffin wax emulsion (with 2.0% solid content) and then subjected to thermal modification (TM) in an oven at 180°C and 220°C for 4 and 8 h. The contact angle (CA), surface free energy, water absorption rate (WAR), anti-swelling efficiency (ASE), and bending properties of the control and modified samples were investigated. Moreover, the chemical and morphological alterations were analyzed by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Both the wax impregnation and TM decreased the surface wettability, water absorption, and tangential swelling, while the combination of wax and thermal treatment exhibited the best water repellency and dimensional stability, indicating the synergism between the two procedures. However, the wax preimpregnation did not affect the mechanical properties of thermally modified wood. The FTIR, SEM, and XPS analyses confirmed that the synergistic effect is mainly due to the redistribution of the paraffin wax during TM rather than its impact on the chemical changes caused by thermal degradation.

Download Full-text

Polyacrylonitrile (PAN) nanofiber mats for mushroom mycelium growth investigations and formation of mycelium-reinforced nanocomposites

Journal of Engineered Fibers and Fabrics ◽

10.1177/15589250211037982 ◽

2021 ◽

Vol 16 ◽

pp. 155892502110379

Author(s):

Marah Trabelsi ◽

Al Mamun ◽

Michaela Klöcker ◽

Bennet Brockhagen ◽

Franziska Kinzel ◽

...

Keyword(s):

Energy Saving ◽

Mycelial Growth ◽

Cost Effective ◽

Fungal Mycelium ◽

Mycelium Growth ◽

Additional Tool ◽

Composite Fabrication ◽

Synthetic Materials ◽

Nanofiber Mats ◽

Pan Nanofiber

Mycelium-bound composites are new environmentally friendly, cost-effective and sustainable materials, enable energy-saving bio-composite fabrication, and provide an alternative to synthetic materials. Current research on mycelium-based composites reports on relatively coarse material compositions such as rice husks, cotton residues, sawdust, leaves and bio-waste, etc. According to research, very few publications report on mycelium-reinforced composites with the use of nanomaterials and this topic is under-researched and this study helps to fill this gap. The focus of this study deals with the preparation of mycelium-reinforced nanocomposites including nanofiber mats and the investigation of the different nanofiber mat morphologies on the growth of fungal mycelium. The mycelium macrofibers from Pleurotus ostreatus fungi were grown on polyacrylonitrile (PAN) nanofiber mats. Different morphologies of nanofiber mats such as fibrous and non-fibrous membrane areas or a mixture of both were used for mycelial growth with an additional nutrient. Moreover, mycelium/PAN nanocomposites were oxidative stabilized and carbonized and mycelium retains its morphology. For faster color differentiation between mycelium and nanofibers, PAN nanofiber mats were dyed in a one-step process by adding dye powder to the electrospinning solution as an additional tool. No significant differences in mycelial growth and morphology were observed regarding the different nanofiber mat types and the use of dye. These mycelium-reinforced nanocomposites are promising for many applications such as medicine and biotechnology, air and water purification and filtration, vertical farming, architecture, etc., and enable energy-saving bio-composite fabrication.

Download Full-text

Extended-pour and conventional alginates: effect of storage time on dimensional accuracy and maintenance of details

Dental Press Journal of Orthodontics ◽

10.1590/2177-6709.26.3.e2119251.oar ◽

2021 ◽

Vol 26 (3) ◽

Author(s):

Sandro Basso BITENCOURT ◽

Isabela Araguê CATANOZE ◽

Emily Vivianne Freitas da SILVA ◽

Karina Helga Leal TURCIO ◽

Daniela Micheline dos SANTOS ◽

...

Keyword(s):

Dimensional Stability ◽

High Stability ◽

Digital Camera ◽

Dimensional Accuracy ◽

Dimensional Change ◽

Clinical Results ◽

Dimensional Changes ◽

Plastic Bags ◽

Significant Difference ◽

Student’S T

ABSTRACT Objective: This study aimed to evaluate the dimensional stability and maintenance of details of conventional and high stability alginates up to 5-day storage. Methods: Two types of alginates were selected (n=10) for this study, conventional (Hydrogum) and high stability alginates (Hydrogum 5), which were produced with the aid of a cylindrical metal block and a ring-shaped metal mold (Specifications 18, 19, and 25, ANSI/ADA). Ten images were obtained from the molds for the dimensional stability test, which were taken immediately after their production and at each different storage periods (15 min, 24 h, 48 h, 72 h, 96 h, and 120 h) by a digital camera. The specimens were kept hermetically sealed in plastic bags (23°C) and then used to obtain 140 (n=70) dental stone models, used in the detail reproduction test, in which the angular accuracy of three grooves (20 µm, 50 µm, and 75 µm) was observed at each period. The details reproduction accuracy was classified using a predetermined score classification. Measurements of dimensional changes were made in the Corel DRAW X6 program. The data were submitted to the Student’s t-test (α?#8197;= 0.05). Results: A statistically significant difference concerning the size of the matrix was observed after 24h for both alginates, and a statistically significant negative linear dimensional change (contraction) was verified after 24 h of storage (1.52% for the high stability alginate, and 1.32% for the conventional alginate). The high stability alginate kept the full details for 72 hours, while the conventional alginate, for 24 h. Both alginates reproduced the 75 µm groove at all storage periods. Conclusion: Impressions made with both alginates presented satisfactory clinical results when the alginates were immediately poured.

Download Full-text