Additive Inclusion

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National Textile Center Annual Report: November 1999

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1

National Textile Center

Project No.: C-98 S01

Competency: Chemical Systems

Web site: http://www.ntcresearch.org/current/year8/C-98S01.htm

Delivery of Textile Additives with Inclusion Compounds

Project Team:

Leader Alan Tonelli (NCState) Polymer Science

Email: [email protected] Phone: 919-515-6588

Members: Peter Hauser( NCState) Org. Chem./Tex. Additives

Students: Jianshuo Niu(NCState), Cristian Rusa(NCState, visiting scholar from Romania)

Objective:

To determine the feasibility of replacing the current methods for incorporating additives into polymer fibers or their

resultant fabrics with cyclodextrin (CD) inclusion compound (IC) delivery of textile additives. To assess those areas

of the textile industry that rely on chemical auxillaries that are most likely to be impacted by the CD-IC technology.

To identify and interest a team of textile specialists with expertise in the textile additives/auxillaries areas and intro-

duce them to the additive-CD-IC technology for the purpose of obtaining their assessments. To further evaluate the

performance and effectiveness of CD-IC delivered antibiotics and flame retardants successfully begun during the

initial portion of our seed grant study. Continue to identify textile additives with delivery problems, attempt to form

their CD-ICs, and study their effectiveness when they are embedded directly into fabric fibers. Expand our prelimin-

ary attempts to chemically attach CD to cotton fibers and fabric with the use of coupling agents to produce fabric

with the potental for filtering out or trapping unwanted gases or liquids. Begin to employ derivitized CDs in an att-

empt to tailor both the compatibility of the CD-IC with the carrier polymer and the conditions under which the CD-

IC is disrupted and releases its guest additive.

Relevance to NTC Mission:

Many textile products rely on additives to enhance their performance. These additives are comonly applied to the

fabric by padding from an additive bath. Depending on the additive and the constituent fibers of the fabric, it is often

difficult to deliver the additive to the fabric in sufficient quantity or with sufficient fastness to achieve long-termadditive function. If instead a cyclodextrin (CD) inclusion compound (IC) formed with the additive was embedded in

the constituent fibers during their spinning, then a more effective and more permanent delivery of the additive might

be achieved. In addition, additive delivery via CD-ICs may permit on-demand release of the additive. For example,

perspiration permeating a garment during active excercize might disrupt the embedded, additive-CD-IC crystals

releasing the additive, which in this application might be a deodorant or biocide. It may be possible for fabric whose

fibers contain embedded, water repellant-CD-IC crystals to confer on-demand water repellancy when worn in the

rain. When an additive is delivered in the form of its CD-IC crystals, it is protected from the environment encounter-

ed both during and after embedding into the carrier polymer fibers. It becomes active only after exposure to con-

ditions which disrupt the additive-CD-IC crystals. In addition to indefinite shelf-life, the CD-IC protection of the

guest additive provides some control over when and how the additive is delivered and the physical nature of the

additive itself. In our preliminary study of PET films embedded with CD-IC crystals containing a flame retardant

guest, we have been able to deliver the normally liquid flame retardant in a solid form that only becomes active and

functions to retard burning when the embedded PET fims are exposed to flames. Our recent success in forming CD-ICs with dyes, a spermicide, and antibiotics provide further opportunities to tailor and control the release of these

guests to achieve textile products with enhanced properties by this possibly novel processing method.

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State of the Art:

We have recently demonstrated the feasibilty of forming CD-ICs with a variety of polymers and small-molecule

guests. These CD-ICs are thermally stable with melting points in excess of 275 C, and may be embedded directly

into carrier polymer fibers and films during their melt fabrication. For carrier polymers with higher melting points,

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solution spinning and casting with polymer solvents that do not dissolve the CD-IC crystals may be used, and the

selection of solvent can be controlled by employing neat or derivatized CD when forming the ICs. The polymer or

small-molecule guest contained in the CD-IC and embedded in the carrier polymer fiber or film may be released into

the carrier polymer by emmersion into an appropriate solvent that penetrates but not dissolves the carrier polymer

and disrupts the CD-IC. Using this approach we have fabricated polymer-polymer composites and have delivered

dyes, antibiotics, and flame retardants to fibers and films made from nylon and polyesters. This means of additive

delivery has several advantages over the traditional method of padding on textile additives from an application bath.Provided a CD-IC can be formed with the guest additive, the resulting IC is a crystalline solid independent of the

physical state (gas, liquid, or solid) of the neat guest. Consequently we can incorporate additives into solid poly-

mers by means of solid CD-ICs and subsequently release the additives in situ even if they are gases or liquids.

The ability of CD-ICs to function as stable, solid additive containers means that volatile liquid and gaseous

additives can be incorporated into and delivered by and to solid polymer fibers, films, and fabrics, with their

delivery tailored to on-demand exposure to various environmental conditions such as temperature, solvents, and

gases. We are in the early stages of exploring the potential benefits of delivering textile additives/auxillaries by

means of incorporating their CD-ICs directly into the constituent textile fibers, but already we have demonstrated

the ability to dye nylon from the inside out, to fabricate antibiotic, bioabsorbable sutures from poly (L-lactic acid)

fibers embedded with neomycin-beta-CD-IC at 100 ppm levels, and to flame retard PET films with very small

quantities of a beta-CD-IC formed with a commercial liquid flame retardant. Derivatized beta-CD(monochloro-

triazinyl) has been shown to complex phenophthalien less strrongly in solution than beta-CD. The beta-CD der-

ivative has been chenically bound to cotton fabric, and we are beginning to test whether or not these bound CDscan remove certain molecules from gas or liquid streams or can be made to complex several textile additives to

be released later during fabric use. Even more recently we have successfully formed CD-ICs with an FDA-

approved antibacterial(Trichlosan, Ciba-Giegy) and the spermicidal nonoxynol-9(Jeen International). The

antibacterial-beta-CD-IC embedded in poly(epsilon-caprolactone) films has been observed to prevent the growth

of E. coli bacteria, while the spermicidal-alpha-CD-IC has not yet been tested for efficacy.

References

L.Huang and A. E. Tonelli, J. Macrmol. Sci., Revs. Macromol Chem . Phys., 38(4), 781, 1998;

Intelligent Materials for Controlled Release, S. M. Dinh, J. D. DeNuzzio, A. R. Comfort, Eds.,

ACS Symposium Series #728, Chap. 10, 1999.

A. E. Tonelli, Polym. International., 43, 295, 1997.

L.Huang, H. Taylor, M. Gerber, P. Orndorff, J. Horton, and A. E. Tonelli, J. Appl.. Polym. Sci.,

XX, yyyy, 1999.L. Huang, M. Gerber, H. Taylor, J. Lu, E. Tapaszi, M. Wutkowski, M. Hill, A. Harvey, C. C. Rusa,

and A. E. Tonelli, "Creation of Polymer Films with Novel Structures and Properties by Processing

with Inclusion Compounds", Symp. On Film Formation, Amer. Chem. Soc. National Meeting, New

Orleans, Aug. 22, 1999.

Approach:

Cyclodextrins are 6, 7, and 8-membered rings (alpha, beta, and gamma-CD) composed of alpha-1,4-linked D(+)-

glucopyranose units, which are produced during the enzymatic degradation of starch (See Figure 1). Because of

their internal cavaties, CDs may act as hosts and readily form ICs with a wide variety of guest molecules. CD-ICs

maybe soluble or they may form crystalline solids. We have successfully formed polymer and small-molecule CD-

ICs over the past few years. In the former case we have studied polymer-ICs formed with CDs and other hosts to

learn about the conformational and motional behavior of extended polymer chains in a highly constrained environ-

ment (See Figure 2). Note that in a polymer-CD-IC each polymer chain is isolated from its neighbors by the walls

formed by the stacked columns of CDs and is highly extended by the narrow constraining diameter of the CD rings.As depicted in Figue 3, we have been fabricating polymer-polymer composites. After embedding polymer-B-CD-IC

in a polymer-A phase, the sample is washed with a solvent for CD that does not dissolve either polymer-A or poly-

mer-B. In this manner we fabricated several composite polymer film and fiber samples. Most recently we have been

successful in forming CD-ICs with several small-molecules that are polymer additives or auxillaries. Dyes, an anti-

biotic, and a flame retardant have been included as guests in CD-ICs. In very preliminary observations of nylon and

polyester films and fibers embedded with these additive-CD-ICs, we have observed their internal dyeing, their ability

to prevent the growth of E. coli bacteria, and their resistance to burning when subjected to an open flame for 2 sec..




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We have begun to compare the behavior of the films and fibers containing the additive-CD-ICs with comparable

samples containing the same additives, but delivered neat by traditional methods. We wish to broaden the scope of

our studies to consider the delivery of fiber spin finishes, water repellants, antistats, stain repellants, antifungals, and

fabric pigments and or printing inks. In parallel work, Peter Hauser has been attempting to chemically bond CD and

derivatized CDs directly to the cellulose chains in cotton fabric with the aid of coupling reagents. The goal of these

investigations is to modify cotton so that it may form ICs between its attached CDs and a variety of small-molecule

guests. If successful, we anticipate using the cotton chemically modified with CDs to be able to trap and filter out

certain small-molecule targets upon exposure to various gas and/or liquid mixtures. This technology might have

uses in filtering and additive delivery applications. Peter and Jianshuo Niu have succeeded in attaching the de-

rivatized-CD to cotton fabric.

Next Year’s Goal:

Having explored and found feasible the CD-IC method of incorporating textile additives during the seed project

period, we now wish to expand our investigation to other textile additives. In addition, for all additives delivered

with the CD-IC technology, we must compare the resultant textile test samples and/or products with similar samples

containing the same additives that were delivered by traditional means. As we have with our preliminary flame re-

tardant and antibiotic work, we will seek to make contact with a textile additive/auxillary manufactures to not only

obtain additive samples, but to eventually furnish additive-CD-ICs and textiles samples containing CD-IC-delivered

additives to these manufacturers for their in-house testing. Peter Hauser learned at the recent ITMA meeting in Paris

that laminating fabrics by bonding with low-melting polyesters is expanding rapidly. Mixing small amounts of add-

itive-CD-IC crystals with the low-melting polyester powder should provide an effective means of delivering a wide

range of textile additives to laminated fabrics.

Outreach to Industry:

We have already made contact with major manufacturers of flame retardants, sutures and medical polymers, drugs,

food packaging, and fibers. Preliminary discussions with a manufacturer of nylon and polyester webbing used in

safety harnesses may lead to developing fibers containing CD-ICs with guests that are released on abrasion or to




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threshhold exposures of UV radiation. These detection fibers could be incorporated into the webs and serve as a

means for indicating replacement of the safety harness. For each new type of textile additive we consider, an

appropriate industry contact will be attempted.

Acknowledgements:

Janshuo Niu and Cristian Rusa are graduate students working on this project. We are grateful to Albright andWilson, Ciba Specialty Chemical, and Jeen International for providing samples of their flame retardants,

Trichlosan antibacterial, and the spermicide nonoxynol-9, respectively.

ABSTRACT

Many textile products rely on additives to enhance their performance. These additives are comonly applied to the

fabric by padding from an additive bath. Depending on the additive and the constituent fibers of the fabric, it is often

difficult to deliver the additive to the fabric in sufficient quantity or with sufficient fastness to achieve long-term

additive function. If instead a cyclodextrin (CD) inclusion compound (IC) formed with the additive was embedded in

the constituent fibers during their spinning, then a more effective and more permanent delivery of the additive might

be achieved. In addition, additive delivery via CD-ICs may permit on-demand release of the additive. For example,

perspiration permeating a garment during active excercize might disrupt the embedded, additive-CD-IC crystalsreleasing the additive, which in this application might be a deodorant or biocide. It may be possible for fabric whose

fibers contain embedded, water repellant-CD-IC crystals to confer on-demand water repellancy when worn in the

rain. When an additive is delivered in the form of its CD-IC crystals, it is protected from the environment encounter-

ed both during and after embedding into the carrier polymer fibers. It becomes active only after exposure to con-

ditions which disrupt the additive-CD-IC crystals. In addition to indefinite shelf-life, the CD-IC protection of the

guest additive provides some control over when and how the additive is delivered and the physical nature of the

additive itself. In our preliminary study of PET films embedded with CD-IC crystals containing a flame retardant

guest, we have been able to deliver the normally liquid flame retardant in a solid form that is only delivered and

functions to retard burning when the embedded PET fims are exposed to flames. Our recent success in forming CD-

ICs with dyes and antibiotics provide further opportunities to tailor and control the release of these guests to achieve

textile products with enhanced properties by possibly novel processing methods. We are in the early stages of

exploring the potential benefits of delivering textile additives/auxillaries by means of incorporating their CD-ICs

directly into the constituent textile fibers, but already we have demonstrated the ability to dye nylon from the insideout, to fabricate antibiotic, bioabsorbable sutures from poly (L-lactic acid) fibers embedded with neomycin-beta-CD-

IC at 100 ppm levels, to confer antibacterial activity to low melting polyester films embedded with trichlosan-beta-

CD-IC, to form a crystalline alpha-CD-IC with the liquid spermicide nonoxynol-9, and to flame retard PET films

with very small quantities of a beta-CD-IC formed with a commercial liquid flame retardant. In particular we

envision that CD-IC delivery of textile additives might be particularly appropriate for laminated fabrics that are

bonded together with low-melting polyester adhesives, because the additive-CD-IC crystals can be easily mixed

with the low-melting polyester powder and will not melt or be disrupted during the lamination process.

.

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