2018 Materials Track Abstracts
HeiQ, through its research partnership with Deakin University, Australia, has developed an innovative process for the synthesis of Short Polymer Fibers (SPF), a revolutionary, patented process for the manufacture of micro-fibrous polymer structures with diameters of 0.1 to 5 μm and lengths of 1 to 1000 μm – currently the smallest fiber size for the textile finishing market in the world. SPF may be made from many materials, the wide choice of functional SPF ingredients opening new opportunities for innovative textile surface functionalization (e.g. our Real Silk which covers “common” materials like cotton or polyester with minute silk fibers). The high degree of interaction of linear filamental structure of the SPF materials with fabric substrates offer increased durability compared to particles with point-wise interaction only.
Eastman Chemical Company is introducing a cellulosic yarn, the new name in fashion apparel. What is new?
– Dyeing blends at high temperature that include an elastomer
– Heat transfer printing
– Optimizing wet fastness
Applications and properties for Naia include:
– Expanded fashions from ladies’ intimates to casual wear.
– The hand is very soft and luxurious and wrinkling is minimal.
– Jet dyeing with disperse dyes at 100-130 C is the preferred method of dyeing knits.
– Fabrics include this fiber alone or with polyester, nylon and elastomers.
– A new application is heat transfer printing much the same as polyester.
– Studies will show wet fastness with and without an after scour. Comparisons of standard wash fastness testing vs actual home laundry methods will be presented.
At Bolt Threads we are making fibers for the textile industry that are inspired by natural protein polymeric materials. The myriad of unique properties and inherent environmental compatibility of these polymers is our motivation for developing a molecular biology platform that is capable of manufacturing these materials via large-scale fermentation. With genetic-level control over the amino acid sequence, we are capable of fine tuning the polymer processing windows and functional material properties. Today, we are capable of producing a recombinant spider silk protein at commercial scale and spin this material into filament and staple yarns. These filaments exhibit spider silk biomimicry and can be generated with high consistency and at large volumes. This first fiber demonstrates the baselined capability of our designer protein polymer pipeline.
Piezoelectric ceramic and polymer composites have been shown to have remarkable piezoelectric constant. However, such composites lack flexibility and breathability and sometimes have health issues for application in wearable fashion. The said limitations can be alleviated by electrospinning piezoelectric polymers containing non-toxic piezoelectric ceramics into porous membranes. Here we report on a novel breathable piezoelectric membrane which has zinc oxide (ZnO) nanorods grown on the surface of electrospun polyvinylidene fluoride (PVDF) nanofibers using a hydrothermal method. Significant improvements in the piezoelectric response of PVDF membrane was achieved without compromising breathability, conformability, or health risk of the material. PVDF is one of the most frequently used piezoelectric polymers due to its high piezoelectric coefficient values, and unlike many piezoelectric ceramics containing heavy metal, ZnO is a non-toxic material which has been widely used in many fields of applications including cosmetics. The fabrication process is simple and economical due to no additional poling process needed for PVDF membranes after electrospinning in a high electric field, and ZnO growth temperature being lower than water boiling temperature in aqueous solution.
The rapidly emerging field of soft robotics presents a new opportunity to develop wearable assistive technology optimized for the needs of individuals with residual capacity as well as for augmenting human performance. Unlike their rigid counterparts, soft wearable robots are lightweight, intimately conformal to the body and can more easily fit a range of sizes. The hierarchical structure and flexible/conformal nature of textiles provide an ideal platform to construct these wearable robotic systems. Textiles impart the ability to tune mechanical properties for use in inflatable actuation profiles or to anchor to the body and distribute and route forces through attachment points in cable driven systems. Looking forward, additional functionalities will be embedded into the textile beyond structural needs including sensing, and flexible electronic routing.
coated nylon filament as inner electrode, a PVDF (polyvinylidene fluoride} electroactive layer prepared by electrospinning deposition process followed by PVDF solution coating, and a 60 nm silver outer electrode applied by electron beam physical vapor deposition. The resultant filament exhibited a more even and durable structure compared with two piezoelectric filaments developed using PVDF solution coating and electrospinning deposition process. Under a cyclic compression of 0.02 MPa at 1.6 Hz, a 3-cm long filament can produce an average peak-to-peak open-circuit voltage of 0.76V. The high-performance, durable and flexible piezoelectric filament showed a great potential to be used as wearable energy harvester to scavenge mechanical energy of human movements.
Embedding electronics in textiles provides the opportunity to enable those textiles as a communication platform amongst humans and machine interfaces. Electronic-textiles (E-textiles) is used not only in smart garments, but also products where textile materials are used around the human, such as air/liquid filters, automotive interiors, sound insulation to impart features like sensing, actuating, communication and energy harvesting. However, integrating hard electronics in soft, comfortable and breathable textile materials is challenging to manufacture a without hindering the original intent of the textile. Herein, printing of functional materials (conductive, dielectric inks) on textile surface is demonstrated as a simple automated process of manufacturing e-textiles products. The fundamental structure-property relationship and process-property relationship are analyzed to define the three-dimensional resolution of the conductive ink in the textile fibrous structure. Two fundamentally very different types of printing processes are discussed: 1) a contact-based screen printing method, and 2) a drop-on-demand based direct-write process. These methods are examined to define how the ink microstructure embedded in the fibrous structure influences device designs. Demonstrations of how to use these printing technology are provided that can be adopted to print flexible and durable devices. In particular, the interaction of conductive materials interaction with fibers to define the device resolution, performance and durability. In addition, we also demonstrate the development of novel device architectures for printing flexible vertical interconnects, large area heaters and a smart wearable textile antennas.
Venous disease in lower limb can range from minor asymptomatic incompetence of venous valves to chronic venous ulcers. The established gold standard of treatment is graduated compression using compression bandages or stockings. However, these conventional methods are incapable of delivering required pressure profiles. The aim of present research is to revolutionize the compression therapy by using a novel active compression system to deliver accurate pressure profiles using a series of inflatable mini bladders. Two types of commercially available silicones were tested for the application, and the inflation/deflation heights and pressure transmittance characteristics of mini bladders were analyzed experimentally. The results showed 70-80% of inlet pressure transmittance onto treated surface. Further, FEM simulations of inflatable mini bladder showed a 60-70% agreement with the inflation/deflation experimental heights.
Transmissions of deadly diseases such as Ebola and Methicillin-resistant Staphylococcus aureus (MRSA) have been known and are public threats due to frequent outbreaks. With the current personal protective equipment (PPE) and practices, infection rates of healthcare workers by the most contagious diseases are still very high, and some of drug resistant diseases have been spread to communities. Thus, novel textiles that can provide increased protection for healthcare workers and the public from transmission of the contagious diseases should be developed. So, what type of textiles can provide such desired functions? This presentation will discuss the biocidal functions of textiles and proper technologies that can meet the requirements from protection of publics from these biological agents, as well as future directions in the research area.
A variety of natural and synthetic fibers are employed in hemostatic dressings. Here we demonstrate the use of greige cotton as a functional fiber, which when combined with hydrophilic and hydrophobic fibers in hydroentangled nonwoven materials, promotes accelerated clotting. A biophysical approach was developed to identify fiber compositions that promote hemostasis. The structure/function characterization of greige cotton-based dressings was based on the relationship of material electrokinetics to the rate of fibrin and clot formation. When coupled to material absorption capacity and wicking determinations, materials that promote a rapid onset of clotting were identified. In vitro assessment of whole materials that promote hemostasis was completed using the Lee White Clotting assay to provide a structure versus function profile of hemostatic activity for selection of leads.
A major revolution in the performance of polymer (PET) fibers was enabled by engineering improvements that raised rate of fiber production from about .1 mile/minute to about 4 miles/minute (~1960). Understanding polymer crystallization under stress (high speed extrusion) led to new insights in the process-structure-property relationships of polymers and identified the importance of polymer melt and solid state molecular chain orientation (Ward) on the mechanical performance and dimensional stability of the resulting fiber (PET tire cord, Dacron for sutures). The tyrosine–based pseudoaminoacid resorbable polymers (Kohn) show elements of both high stress extrusion and liquid crystalline behavior when spun into fibers from the melt. Knowledge of the impact of chain conformation on polymer product performance leads directly to the choice of isosorbide or 2.5, furan dicarboxylic acid as sustainable (bioderived) monomers and the use of these monomers to create sustainable polymers with target performance characteristics. In all of these examples, problems were solved through an understanding of (polymer) chemistry and physics applied to systems where the independent and dependent variables of interest were different but the technical framework was the same.
Clothing wear comfort is a high priority need of wildland firefighters whose work often requires strenuous sweat generating activity in thermally stressful environments. This presentation describes a study that determined the effects of FR clothing materials and base layers on the amount and location of sweat absorbed in the wildland firefighter clothing. It examines relationships between measured moisture management properties and perceived human comfort response in laboratory wear trials designed to simulate wildland firefighting conditions. It shows the effect of single and double layer protective clothing systems and the effect of a high wicking FR t-shirt material on moisture absorption and comfort in wildland firefighter clothing. It shows the correlations between moisture management tests and wearer perceived moisture sensations in wildland firefighter FR clothing.
Appropriate personal protective equipment (PPE) is a basic risk mitigation tool that provides an effective barrier to humans engaged in pesticide application. To validate this concept, a multi-method approach was adopted to record user issues and functional limits to the effective performance of PPE. Eight greenhouse pesticide applicators (4 males and 4 female) and eight farm workers (4 males and 4 female) from upstate New York participated in the study. Information was collected regarding (1) participants’ demography (2) work dynamics and work environment, and (3) issues and concerns related to the use of the PPE. Findings of this study highlighted four key issues related to the existing PPE (i) heat stress (ii) mobility (iii) integrity of the interface and contamination and (iv) behavioral responses.
Due to disproportionate rates of football players experiencing heat illness injuries, there is a need to focus on the thermal comfort of athletes. Clothing ventilation in athletic uniforms may significantly improve thermal comfort. These improvements are especially important for football athletes as they perform intense physical activity in thermally stressful environments. The purpose of this research was to investigate the thermal comfort of different ventilated football uniform designs. Air permeability testing and a human wear trial were conducted to determine thermal comfort properties. Three ventilated football uniforms (mesh, laser micro-perforated, and combination) were evaluated. Heart rate, perceived exertion, perceived comfort, and thermal sensation were analyzed. Findings illustrate significant differences in air permeability and perceived thermal comfort amongst the three ventilated uniform types.
Chronic exposures to toxic combustion products in the fireground environment are believed to contribute to higher rates of cancers experienced by firefighters. When used during fire suppression and overhaul stages, the self-contained breathing apparatus protects the highly susceptible respiratory tract from the toxicants in smoke and soot. However, the simple knit protective hoods that firefighters wear provide minimal protection from particulate deposition on the skin of the face and neck. Newly developed particulate blocking hoods are available on the market, but the impacts of these additional layers on the thermal protection, thermal burden, mechanical properties, and situational awareness have yet to be fully investigated. This presentation provides an explanation of the holistic assessment of the protective hood that is being developed at NC State University.