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Posts tagged with “AATCC 20”

Vartest’s Outstanding Achievements and Service Recognized by AATCC

Adam Varley, Vartest’s Technical Director & COO was honored to be the recipient of the TCR Service Reward “In Recognition for His Service to AATCC Research Committees”. On Thursday, April 3rd 2014, Adam attended a luncheon at the Crowne Plaza Resort in Asheville, North Carolina, and was presented with this award for “his contribution toward the development of the AATCC Fiber ID Technical Supplement and the continuous updating of AATCC Test Methods 20 and 20A.”


Polyester Fiber And Triexta Fiber Generic Subclass Testing Capability Enhanced

Using a combination of analytical techniques as well as experience with weft knit, warp knit, woven and non woven textile structures, Vartest provides a unique capability for analyzing polyester fiber and the polymers which make them up including FTC designated polyester fiber subclasses and related fibers.


Micro FTIR Analysis Allows Molecular Structure Analysis Of Single Fibers And Filaments

Preparing Vartest's FTIR Microscope For Textile Fiber Work With Liquid Nitrogen


The Federal Trade Commission covers but is not limited to three related polyester polymers used to produce textile fibers: Polyethylene terephthalate (often abbreviated as PET and the polymer which makes up the world’s most commonly used textile fiber), polytrimethylene terephthalate (FTC generic sub class triexta and also commonly known as PTT and with the current IUPAC name poly(propyleneterephthalate) and polybutylene terephthalate (often abreviated as PBT). The structures of PET, PTT and PBT are shown in the following ball and stick models:
Polyester Polymer Chains Modeled With Chem Bio 3D Ultra

Three Repeat Unit Chains Of Polyethyleneterephthalate, Polytrimethyleneterephthalate and Polybutyleneterephthalate


Fibers made of PTT may be labelled “Triexta” however fibers composed of PBT do not have an FTC designated subclass and so can be labeled “Polyester” and be more fully characterized as PBT Polyester. Fibers made of PET are usually simply labeled as “Polyester”.
The chief difference in chemical structure between these three polymer groups is the addition of a single methyl group to the polymer repeat with each of PTT and PBT. PET has two methyl groups in the hydrocarbon chain connecting phthalate esters, PTT three and PBT four. The addition of methyl groups leads to significant changes in fiber performance in end use, making PTT for example, particularly suited to end uses such as carpeting. The addition of methyl groups to the hydrocarbon chain also leads to decreasing melt point as seen in the following differential scanning calorimetry curves:


PET, PTT and PBT compared

Differential Scanning Calorimetry Comparison Of PET, PTT and PBT

Micro Fourier transform infrared analysis helps to differentiate these polymer groups with clear separation of PBT, PTT and PET capable with even a single fiber and enabeling dissected filament yarns from a complicated structure such as a multi bar tricot warp knit to be positively identified both qualitatively and quantitatively as seen in the following light micrograph:
Triexta (PBT) and conventional textile polyester (PET) dissected from a two bar tricot warp knit fabric.
Once dissected micro FTIR spectra of the yarns above are obtained and run against a search library for identification. The image above shows the dissected PET top bar yarn of a 1-0/2-3 fully threaded tricot structure as well as the PBT 1-2/1-0 back bar. A micro Fourier transform infra red analysis of SmartStrand carpet fiber is shown below with a 95% Euclidean hit to a control sample of known triexta fiber:
Eulidean Library Search For Triexta

Micro Fourier Transform Infra Red Analysis Of SmartStrand Triexta Fiber

Nuclear magnetic resonance (NMR) testing complements this work differentiating between PET, PTT and PBT as seen in the following Hydrogen-1 NMR and Carbon-13 NMR comparison done at 300 megahertz with deuterated trifluoroacetic acid as the solvent:
Comparison Of PET, PTT and PBT

300 Megahertz Nuclear Magnetic Resonance Spectra

Polyester Comparison Via FTIR

300 Megahertz Nuclear Magnetic Resonance Spectra

Vartest provides in depth analysis of all characteristics of fiber make up, morphology and performance assisted by a proprietary search library of thousands of fibers from all markets and end uses.