Medical, Nonwovens, & Technical Textiles Symposium
October 6-7 , 2008
Sheraton Imperial Hotel - Durham, North Carolina

Medical, Nonwovens, & Technical Textiles will be the focus of this two-day program to be held October 6-7 at the Sheraton Imperial Hotel in Durham, NC USA.  This program is being developed by AATCC’s Material Interest Group and chaired by Dr. Philip J. Brown with Clemson University. Participants will have an opportunity to tour the Nonwovens Cooperative Research Center (NCRC) at the conclusion of the program on the 7th.

Click here to download the program timetable.

Click here to view the registration brochure.

Confirmed speakers include:

Next Generation Carbon Fibers Based on Polyacrylonitrile/carbon Nanotube Composites – Satish Kumar, Georgia Institute of Technology

Abstract Unavailable

Making Composites Using the Three Dimensional Engineered Preform (3-DEP) Process - Mark Janney, Materials InnovationTechnologies

MIT-LLC has developed a method for making chopped fiber polymer matrix composites (PMCs) that has the potential to revolutionize the industry.  The Three Dimensional Engineered Preform (3-DEP) process represents the state-of-the art in chopped fiber preform manufacture.  The 3-DEP process produces a homogeneous fiber distribution within parts, and consistent part weights and dimensions from part-to-part.  MIT-LLC has demonstrated the ability to mold composites with highly complex part geometries.

The key to the 3-DEP process is a slurry molding machine in which the vacuum forming tool is supported on a gimbaled mount.  The process can independently control three major forming parameters: (1) flow velocity in the slurry tank, (2) motion of the forming tool, and (3) vacuum level in the forming tool.  The ability to manipulate these three parameters provides control over the amount and distribution of fiber deposited and the orientation of those fibers.  The process works well with carbon, glass, aramid, polypropylene, polyethylene, and natural fibers. 

Recently, work has been completed on a real-world part, the front wheelhouse support for the Corvette.  The preform is made in 1" carbon fiber; the part is molded with polyester resin using liquid compression molding on production equipment at the Molded Fiber Glass (MFG) companies.  Results have been quite favorable.  Part-to-part density variation is small (<3.5%) as is within-part density variation (<3.5%).

Development of Autonomous Tissue Expanders for Surgical Reconstruction - David Bucknall, Georgia Institute of Technology

Hydrogels based on biocompatible polymers have been developed which posses not only large expansion ratio but more importantly anisotropic expansion.  These properties make these materials well suited for reconstructive surgical applications including cleft palette repair.

Molecularly Imprinted Fibers with Recognition Capability - Bogdan Zdyrko, Clemson University

Abstract Unavailable

Modeling the Performance of a C-CP Fiber-Based Hepa Filter - Chris L. Cox, Clemson University

The overall goal of this project is to develop high efficiency particulate air (HEPA) filter media, using conventional fiber spinning techniques, with lower pressure drop than current media through the use of shaped fibers. HEPA filters are widely used in both military and civilian applications.

 

This presentation will focus on modeling HEPA filtration, comparing a filter consisting of capillary-channel polymeric (C-CP) fibers with a round-fiber filter.  Numerical techniques including grid generation, finite element solution, and Brownian dynamics simulation will be discussed.  Predictions of pressure drop and filter efficiency under various conditions will be presented.

Novel Technologies for Particulate Filtration - John Larzelere, Naval Surface Warfare Center, Dahlgren Division    

Abstract Unavailable

Protein Separations using C-CP Fibers - R. Kenneth Marcus, Specialty & Custom Fibers LLC

Abstract Unavailable

Water, Chemical, and Energy Recovery by the Applications of Nanotechnology - John J. Porter,

Clemson University

It is possible to recover chemicals, water and energy from industrial waste streams with commercial nanofilters. This was demonstrated with a full scale nanofiltration system treating wastewater discharged from a textile dyeing operation. The savings are tabulated with the identification of additional savings when it is also possible to recover expensive dyes such as indigo. The application of nanofiltration to the treatment of aromatically contaminated ground water is presented.  Stainless steel and ceramic microfilters having pores diameters of 0.03 – 0.2 microns have been shown to be capable of behaving as nanofilters by rejecting anionic dyes and sodium nitrate from water solutions.  The conductivity of the filtering solution is correlated to the Debye length and rejection properties of the membrane. 

KEYWORDS: nanofiltration, chemical &dye recovery, energy conservation, microfiltration

A Study on the Effects of Compression on Morphology of Nonwoven Materials - Sudhakar Jaganathan, Nonwovens Cooperative Research Center

Pore size of is a characteristic parameter that is often of great interest in applications involving nonwoven materials. The influence of compression load on nonwovens’ pore size distribution has not been studied well. Studying the behavior of fibrous materials under compression is important especially because in many applications these materials are subjected to some degree of compression during use. In this work, we present a novel image-based technique to study the changes in the pore size distribution of a fibrous material exposed to compressive load. 3-D imaging is utilized here to study the pore size distribution of the material and develop an empirical correlation as a function of compression.

Geometrical Modeling of Nonwovens Under Compression - Benoit Maze, Nonwovens Cooperative Research Center

Many fibrous materials such as nonwovens are consolidated via compaction rolls in a so-called calendering process. Hot rolls compress the fiber assembly and cause fiber-to-fiber bonding resulting in a strong but yet porous structure. In this presentation, we describe an algorithm for generating 3-D virtual fiberwebs and simulating the geometrical changes that happen to the structure during the calendering process. Fibers are assumed to be continuous filaments with square cross-sections, lying randomly in the x or y direction.  The fibers are assumed to be flexible to allow bending over one another during the compression process. Lateral displacement is not allowed during the compaction process. The algorithm also does not allow the fibers to interpenetrate or elongate and so the mass of the fibers is conserved. Bending of the fibers is modeled either by considering a constant “slope of bending” or constant “span of bending”. The influence of the bending parameters on the propagation of compression through the material’s thickness is presented. In agreement with our experimental observations, it was found that the average Solid Volume Fraction (SVF) profile across the thickness becomes U-shaped after the calendering.

Micro and Nano Fiber Nonwovens using Spunbonding and Hydroentangling - Nagendra Anantharamaiah, The Nonwovens Institute

Methods of manufacturing high strength, high surface area, flexible and durable nonwoven

fabrics are discussed. Bicomponent fibers manufactured using spunbond process, and fibrillated

mechanically through the use of hydroentangling process where the hydroentangling energy is

sufficient for fibrillating as well as bonding the fibers are discussed. Different fiber crosssections

and polymer combinations in the bicomponent system have been explored. Optimal

bonding conditions for the fabrics were identified. Physical properties of such fabrics are

discussed.

3-Dimensional Analysis of Nonwovens - Eunkyoung Shim, Nonwovens Cooperative Research Center

Hydroentangling, where fabric is formed by striking of fine, closely spaced, high speed water jests, is arguably the fastest growing bonding method in the nonwoven industry. Softness, drape, conformability and relatively high strength are the major characteristics that make this bonding technology unique. Despite the method appeal, few understand the impact of water jet on fabric structures. The primary function of water jet is to produce fiber entangling, which induces web integrity. Hydroentangling also offers the ability to split bicomponent fibers and therefore, when used as the method of bonding for splittable fibers, the structure is split and bonded in one step.  However, there is surprisingly little study about the real character of fiber entangling and fiber splitting by water jet. It may be due to its 3-dimensional nature of entanglement. Techniques to analyze of turning, twisting, and bending inside dense web, are almost non-existence and observation of fabric surface and random fabric cross-sections only provide very fragmental information at its best.

 

To provide better understanding of hydroentangling mechanism and fabric structure it produces, we utilized Digital Volumetric Imaging (DVI) and fully investigate 3D structure of hydroentangled fabric. Fiber orientation distribution, variation of solid volume fraction, and splitting of bicomponent fibers will be reported.

Rational Design of a Hemostatic Textile Matrix - Thomas H. Fischer, Entegrion, Inc.

Abstract Unavailable

Electrospun New Biodegradable Drug-Eluting Nanofiber Membranes for Burn Treatment - C. C. Chu, Cornell University

A new family of synthetic biodegradable polymers, amino acid-based poly(ester amide)s (PEA), was synthesized and electrospun into fibrous membranes.  Biological active agents were incorporated into these biodegradable PEA fibrous membranes for the purpose of promoting wound healing. The in vitro release of the biological active agents from electrospun PEA fibrous membranes was studied, and a burst release of the active agent was observed. A sandwich PEA fibrous membrane design was proposed to eliminate such a burst release for providing a sustain and prolong release of the impregnated biological active agents over an extend period.   The unique biological property and potential biomedical applications of these new family of synthetic biodegradable polymers will also be described.

Chitosan/Poly(aspartic acid) Layered Films with Improved Hemostatic Properties - Sam Hudson, North Carolina State University

Abstract Unavailable

Medical Textiles - Versatile In Use but Vulnerable to Microbial Problems - W. Curtis White, Aegis Environmental Management Inc.

Textiles used in the medical industry from nonwovens, wovens, coated fabrics, to composite fabrics are challenged to deliver the performance and aesthetic needs demanded and desired by the user and the purchasing agent.  In most cases these needs parallel those of the consumer and commercial marketplaces and extend from initial use and abuse to disposal or recycle.  In the myriad of textile uses in the healthcare environment microorganisms cause problems of staining, deterioration, odors, biofilms, and disease.

 

This paper will provide an overview of the myriad of microbiological problems associated with textiles used in the healthcare environment and the benefits of durable broad spectrum antimicrobial, intervention and protection technologies.

Textiles for Next Generation Chemical Biological Protection - Eugene Wilusz, Natick Soldier RD&E Center

For many years chemical biological (CB) clothing used by the military has relied on activated carbon as an integral component of the textile system.  The carbon does an excellent job as an adsorbent for hazardous chemicals.  In an effort to develop CB clothing which is lighter weight, more comfortable, and mission friendly, materials research has been ongoing to reduce the quantity of carbon used or even eliminate it altogether.  During the past several years membranes have been developed that have the potential to form the basis of the next generation of protective clothing.  Membranes for this purpose can be of two types – microporous or nonporous.  Microporous membranes can be used in conjunction with a carbon layer.  Nonporous membranes can be used without any carbon or with a minimal amount.  Among the many challenges is the need for the membrane to serve as a barrier to hazardous chemicals while still allowing a significant degree of moisture vapor transport.  It is essential that the permselectivity of the membrane be optimized.  Several approaches to this optimization have been examined, and two are particularly promising.  Ion implantation has been used on the surface by applying monolayers and bilayers of cyclic molecules of controlled pore size to regulate diffusion into the membrane.  Both techniques have led to prototype membranes with improved permselectivities.  Ensembles fabricated from nonporous membranes face the issue of being susceptible to compromise at the interfaces in the clothing system because of pumping action.  Carefully designed closure systems are needed to overcome this concern.  Research is also underway to develop filter fabrics and to incorporate catalytsts and antimicrobial treatments into these textile systems eventually leading to self-detoxifying CB protective clothing.

Flame and Thermal Protective Materials for Combat Clothing and Individual Equipment - Francisco Martinez, Natick Soldier RD&E Center

A large effort in order to protect our Soldiers from the effects of flame and thermal threats in the battlefield has taken place during the last 2 years. The environments where our forces operate and the ever changing threat from explosives and secondary fuel pool fires have driven the flame retardant material developers to incorporate advanced solutions at a system level.

 

In order to enable our forces to perform in demanding environments, where extreme conditions are the norm, engineering multi-functionality into a flame retardant fabric is necessary. In addition, to better understand the threat, a set of system level test methodologies have been formulated and are currently being pursued. Ultimately, the Department of Defense personal protective systems must be evaluated to the reality of the field where they are deployed in order to ascertain any possible performance gaps.

 

This presentation will provide a forum for:

• Understanding military requirements for flame and thermal protective materials
• Review of materials and systems test methodologies
• Trends in FR and thermal protective technologie

Challenges in Fielding Combat Uniforms - Christine W. Cole, Clemson University

Abstract Unavailable

 

Body Armor Composites with Enhanced Comfort and Protection - Arvind Purushothaman, Bellator Group

One of the pressing requirements for the law enforcement personnel and military community is to have a body armor with multiple functionalities such as ballistic protection, slash protection, abrasion resistance and enhanced comfort. This presentation will focus on a novel approach to improve the strength and the comfort of multi-layered ballistic composite. This is achieved by increasing the z-directional strength of the composite by creating fiber channels through the multiple layers of the ballistic fabrics. In addition, the composite will have a next-to-skin layer which can remove moisture away from the skin to enable enhanced comfort. The comfort layer with the help of different blend combination of fibers, not only can provide the necessary wicking, but also can be needlepunched with  one or multiple layers of ballistic fabrics providing improved cohesion and ballistic strength. The abrasion resistance of the composite can be enhanced with the combination of an abrasion resistance layer using different bonding approaches such as adhesive bonding and stitching. This is in addition to the use of needlepunching to bond multiple layers, i.e., comfort and ballistic fabrics. Thse armor vest inserts have enhanced flexibility better than the hard surfaces due to the method of bonding using needlepunching technology. Recent results of this composite shield have shown that depending upon the number of ballistic layers, it is easily possible to achieve Level IIIA protection based on National Institute of Justice standards. This presentation will feature the development and test results of Level IIA to Level IIIA protection composites which are of use to the law enforcement personnel and defense community. 

Understanding the Ballistic Impact Resistance of Polyproylene Fabrics - Tom Godfrey, Natick Soldier RD&E Center

Recently there is increasing interest in the development of polypropylene (PP) fiber reinforced composites as an alternative to glass fiber composites to reduce weight and improve impact resistance. It turns out that some of these materials exhibit surprisingly good resistance to ballistic impact of fragment simulating projectiles as well, in spite of fiber tenacities that are about 25 % of the tenacity of traditional ballistic fibers (e.g., Kevlar KM2®). An initial prediction using a “figure of merit” parameter calculated from fiber properties for one commercial PP material indicated that actual ballistic impact performance was significantly better than expected; this finding prompted a NSRDEC study of the ballistic impact behavior of PP fabrics and composites, a portion of which will be discussed here.

 

We examine the performance of three commercial polypropylene woven fabrics in the framework of a dimensional analysis for ballistic impact on textile armor materials [1].  In the prior work, Cunniff showed that the V50 ballistic limit of both multi-ply dry fabric and composite armor panels could be understood through two dimensionless groups, one of which consists of V50 normalized by a parameter U* raised to the 1/3 power, where U* consists of the product of the fiber specific toughness and longitudinal strain wave velocity. The behavior of a wide variety of Kevlar® materials and PBO fit this two group model well, where U* is calculated using mechanical properties obtained from quasi-static tensile testing of yarns. In this talk we introduce an enhanced method of determining U* for PP materials which captures dynamic response characteristics and accommodates the complexity of the tensile failure process in PP tape yarns; key elements include the direct measurement of strain wave velocity and the selection of an appropriate gage length for tensile tests. Using this method, the ballistic behavior of the PP materials in both dry fabric and composite forms is shown to be consistent with the prior dimensional analysis results. The role of the micro-fibrillar structure of PP tape yarns on quasi-static tensile response and failure, and results from ongoing high rate tensile testing, will be discussed.

 

1. Cunniff, P.M. “Dimensionless Parameters for Optimization of Textile-Based Body Armor Systems” presented at the 18th International Symposium on Ballistics, San Antonio, TX, 15-19 November, 1999.

Tabletop Displays

Participants are invited to socialize with fellow attendees at a suppliers’ reception on Monday evening from 5:30 - 7:00 p.m.  Tabletop exhibits featuring fabrics, garments, techniques, and technologies discussed as part of the program will be featured.  If you are attending the symposium and would like to reserve a tabletop display, click here to download a form to secure your exhibit space.

Optional Tour

Participants will have an opportunity to tour the Nonwovens Cooperative Research Center (NCRC) at the conclusion of the program on the 7th from 3:30-5:00 p.m. 

The Nonwovens Institute is the world’s first accredited academic program for the interdisciplinary study of engineered fabrics through an innovative partnership of industry, government, and academia. Operating on an “Open Innovation” platform, The Nonwovens Institute enables industry and university experts to develop the next generation of nonwoven applications while education and training future industry leaders. The Nonwovens Institute offers a variety of services to the nonwovens and affiliated industries including product development, analytical services, and education and training programs. The institute’s state-of-the-art facilities include laboratories dedicated to fiber, fabric, and polymer characterization, spunbond and melt blown pilot lines with bicomponent fiber capability, carding, cross-lapping, needle punching, hydroentangling, thermal bonding, and spun bond/melt blown/carded web composite capability. Analytical facilities offer the ability to analyze and evaluate materials performance according to many industry specific standard test methods. The Nonwovens Institute also offers special training programs to companies interested.

Registration and Accommodation Information

A registration fee of US$710 (US$475 for individual and corporate AATCC members) will include luncheons, breaks and a copy of all available papers. A student registration fee of US$125 is available to AATCC student members.  Refunds will be made if cancellations are received on or before September 26, 2008.

Overnight accommodations are available at the Sheraton Imperial Hotel, 4700 Emperor Blvd., Durham, N.C. USA, telephone +1 919 941 5050. Reservations should be made directly with the hotel and attendance at the AATCC program should be specified to receive the group rate of US$139 single/double. Reservations can be made online by clicking on the following link http://www.starwoodmeeting.com/StarGroupsWeb/res?id=0806250010&key=9F014. Reservations must be made by September 14 to ensure room availability.

Click here to register online.

Click here to register offline by downloading an AATCC Registration Form and submitting by fax to +1 919 549 8933.*

*If your company is a corporate member of AATCC you will need to register offline.