Analytical Services Laboratory

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The Analytical Services Lab is part of NCSU Wilson College of Textile Engineering, Chemistry and Science Department (TECS).

The lab functions not only as a resource for graduate students to obtain data for their MS thesis or PhD dissertation work, but is also utilized for teaching and service.

  • Outside lab services are mostly in the fields of textile & polymer manufacturing
  • Testing, client interaction and communication is conducted by the ‘on staff’ Laboratory Manager.
  • Client communication is maintained throughout the testing process to minimize unnecessary expenses and maximize the utility of the information generated.
  • Collaboration with a diverse clientele of internal (incl. other NCSU Colleges) as well as external industry sponsors. We make every effort to accommodate testing requests in a timely manner and pricing is competitive to other commercial testing labs.
  • For liability reasons we do not train or permit non-NCSU users on the instrumentation
  • Limited wet chemistry techniques, like fiber burn outs or solvent Soxhlet extractions, are available,.
  • Prices are typically quoted per project based on its complexity, instrument use and time involvement.
  • A legal contract called a Fabrication and Testing Services Order Form “SOF” is set up by the University for industry clients to be signed prior to any testing work performed.
  • Government affiliates and federally funded companies are eligible for the internal pricing structure.
  • The lab does not participate in ‘reverse engineering’ or litigation cases.

Thermal Analysis Instrumentation

Spectroscopy Instrumentation

Chromatography

Contact Angle

Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS)

Thermal Analysis Instrumentation

Differential Scanning Calorimetry (DSC)

DSC measures the amount of thermal energy absorbed or released by a substrate as a function of temperature or time known as “heat flow”.  The TA Discovery DSC 250 with RCS cooler (enables cooling to -90oC) is a heat flux instrument with an autosampler.

Typical Analyses

  • Melting Points (TM) ,
  • Crystallization temperatures (TC)
  • % crystallinity
  • Glass Transition Temperatures (TG)
  • Isothermal holds for kinetics evaluations.

Features

  • Samples can be liquids or solids, including pellets, powders and films
  • Small sample size of 5-10mg
  • Operating range is -900 C to 4500C
  • Heating rates of up to 50oC per minute
  • Units are measured as heat flow (mW) and temperature (oC)

Sample Requirements

  • Must contain crystalline material or be capable of forming crystals during the heating process, resulting in an endothermic melting peak
  • Grinding sample materials should only be done if it will not change their properties.

Relevance to Textile Industry

  • Performance of active wear featuring phase change properties
  • Variation in dyeability of synthetics can sometimes be traced to differences in crystallinity and crystal size, influenced by its thermal history
Amorphous PET Pellet(3)

Thermogravimetric Analysis (TGA)

TGA quantitatively measures weight loss (% or mg) of a sample due to decomposition loss of solvent/water as a factor of temperature or time. The TA Discovery TGA 550 with a standard furnace enables a heating profile from 25 to 950oC with typical heating rates of 10, 20 or 30oC per minute.

Typical Analyses

  • Decomposition profile of liquids or solids
  • Quantitative determination of
    • number of constituents
    • evaporation of volatiles
    • water of hydration
  • Isothermal degradation studies of substrates
  • preliminary analysis to identify decomposition temperature profiles prior to DSC evaluation

Features

  • Typical sample size of 5 – 20 mg
  • Samples are solids or liquids
  • Graph displays temperature (oC) versus weight (mg or %)
  • Available purge gases are N2 and Air.

Sample Requirements

  • Samples can be liquid, solid, films or in powder form.
  • Samples should free of static charge.
  • Samples must not form corrosive gases (e.g. HCl or HF) upon decomposition
  • Sample must not be toxic or carcinogenic
  • Sample should not contain any metal salts or ions

Relevance to Textile Industry

  • Carbon nanotube analysis
  • Quality control of polymeric raw material for fiber extrusion
Ca-Oxalate Decomposition Pattern

Spectroscopy Instrumentation

Agilent Cary 300 & Agilent Cary 5000 UV-Vis-NIR spectrophotometers

UV-Vis instruments are most commonly used to identify the wavelength of maximum light absorbance (lambda max).  Colored solutions typically absorb in the visible region (Vis), whereas colorless chemical containing a suitable chromophore may absorb in the UV region.

Typical Analyses

  • Lambda max (wavelength of peak absorbance)
  • Determination of unknown dye concentrations
  • Absorbance (Abs) or % Transmittance (%T) of solutions over a selected wavelength range
  • Abs, %T and % reflectance (%R) of solid samples

Features

  • Dual beam instruments
  • Integrating sphere modules for solid sample analysis
  • Near Infrared integrating sphere (Cary 5000)
  • Fabric protection software converts plots to numerical UPF value
  • Agilent Cary 300 operating wavelength range 190-800 nm
  • Agilent Cary 5000 operating wavelength range 175-3300nm

Sample Requirements

  • Films must be thin enough to transmit light
  • Solutions may need to be diluted to measure 1.5 or less absorbance units for the calibration curve to be linear

Relevance to Textile Industry

  • Quantitative evaluation of dye solutions
  • Ultraviolet Protection Factors (UPF) determinations of textile substrates for apparel and outdoor fabrics
  • Evaluation of Near Infrared (NIR) absorbing dyes
  • Analyses of dyes for solar cells, medical applications and renewable energy
  • Measurement of thin polymer films
Chart - Blue Dye Solution at Various Concentrations

Diagram - Human Eye Sees Complementary Color
Diagram - Absorbed Versus Complementary Color
  • According to Beer’s Law, absorbance (A) is directly proportional to the concentration, assuming all other variables are constant.
  • Deuterium lamps are used to produce the UV radiation, Tungsten lamps for Vis light.
  • Quantification of dye in a solution requires accurate standards to obtain a calibration curve.

Fourier Transform Infrared (FTIR) Spectrometer

FTIR is used to qualitatively identify unknowns based on the functional groups that make up a molecule.   The lab presently has two Thermo Fisher FTIR models, iS10 and iS50.  The iS50 includes an interchangeable Raman module.

Typical Analyses

  • Identification of substrates, including fibers, powders, films and liquids
  • Contaminant analysis
  • Finish analysis following a solvent extraction, or on a sample of a liquid finish or softener

Features

  • SpectaTM software enables constituent identification of up to four compounds in an unknown sample
  • Extensive spectral libraries
  • iS50 with built-in diamond Attenuated Total Reflectance (ATR) crystal and Raman module with 1064 nm NIR laser
  • iS10 with OMNI ATR sampler with Germanium (Ge) crystal

Sample Requirements

  • Sample to be analyzed must be free of solvents, including water
  • The molecule must be IR active. All organic compounds and polymers are IR active
  • FTIR has limited application for inorganic samples like salts or soil samples.

Examples of Use in the Textile Industry

  • Qualitative finish analysis
  • Identification of fiber blends
  • Bicomponent fiber analysis
  • Analysis of rubber or polymer coatings
Chart - IR spectrum of Acetone

Chromatography

High Performance Liquid Chromatography (HPLC)

The Waters HPLC uses Size Exclusion Chromatography (SEC), a widely used technique for analyzing polymer samples to determine relative molecular weights and molecular weight distributions.

Typical Analyses

  • Number average MW (M̄n), Weight average MW (M̄w), and Peak average MW (M̄p)
  • Molecular weight distribution of polymers (polydispersity)

Features

  • Waters Alliance HPLC with 2695 pump system
  • 2414 RI detector
  • Empower 3 software
  • THF & aqueous column

Sample Requirements

  • Polymers must be soluble in THF or aqueous solutions (typically 0.1M NaNO3)

Examples of Use in the Textile Industry

  • Environmentally induced degradation of polymers
  • Degradation of biomedical textiles
Elution Volume (retention time)
Three overlaid chromatograms of 12 PEO/PEG MW standards
Three overlaid chromatograms of 12 PEO/PEG MW standards
Calibration curve from the 12 MW standards
Calibration curve from the 12 MW standards
Chromatogram of a sample of poly(vinyl alcohol) analyzed using the above calibration curve and showing the M ̅_p.
Chromatogram of a sample of poly(vinyl alcohol) analyzed using the above calibration curve and showing the M ̅_p.

Contact Angle

Goniometer FDS Corp. Dataphysics OCA System

The goniometer measures the contact angle (θ)of water or other liquid a solid substrate.  Angles are measured in degrees, which give an indication of the hydrophobic or hydrophilic surface properties of the substrate. Contact angle is one of the common ways to measure the wettability of a surface and is a quantitative measure of the wetting of a solid by a liquid. The instrument of choice to measure contact angles and dynamic contact angles is an optical tensiometer. A force tensiometers can also be used. … If contact angle is greater than 90°, the surface is said to be non-wetting with that liquid. Wetting refers to the study of how a liquid deposited on a solid (or liquid) substrate spreads, or the ability of liquids to form boundary surfaces with solid states. Contact angle is related both to surface tension and to thermodynamic equilibrium between phases. it is analyzed to measure the wettability of surfaces. Considering a droplet deposited on a horizontal surface, contact angle is defined as the angle formed by the liquid-gas interface with respect to the solid. Usually, surfaces showing contact angle with water higher than 90 are considered hydrophobic and for contact angle lower than 90 degrees hydrophilic. Thanks to the evaluation of surface tension and contact angle it is possible to:

Features

  • Fully automated dispensing, camera and data collection system
  • Drop size as low as 3 µl
  • Static sample stage

Sample Requirements

  • Samples should be at least 1” diameter for multiple measurements
  • Samples should not be contaminated by improper handling (exposing sample surface to natural skin oils)
  • Samples should have relatively even surface for successful measurements
  • Samples should be stable to the environment

Examples of Use in the Textile Industry

  • Characterization of hydrophobicity of knitted, woven or non-woven textiles
  • Characterization of film surfaces
Contact Angle
https://en.wikipedia.org/wiki/Contact_angle
Contact Angle
Image courtesy of intechopen.com

  • The angle between the droplet and solid surface indicates the wettability of the surface based on the measured angle between the droplet and the substrate
  • Water is typically used as the solvent, but other solvents may be used, depending on the application
  • Dedicated syringes are used to dispense each liquid

Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS)

Hitachi TM-4000 PlusXL with Oxford AZtecOne EDS

The Hitachi TM-4000 PlusXL is a high resolution desktop SEM, which uses a thermionic electron emission gun to scan a sample surface, resulting in high resolution images.

Typical Analyses

  • Qualitative elemental analysis and chemical characterization
  • Topographical analysis
  • High resolution images

Features

  • Aztec EDS software included TruMap module to correct element overlap
  • Detectors for secondary electrons (SE), backscatter electrons (BSE), cathodoluminescence (CL)
  • 70mm traverse motorized rotating stage with 90 degree motorized tilt

Sample Requirements

  • Samples should be dry
  • Non-conductive samples can be sputter-coated with a conductive layer to improve imaging
  • Most samples analyzed without destructive sample preparation
  • No color information
  • Typical samples are solid objects, often opaque

Examples of Use in the Textile Industry

  • Inorganic contaminant analysis
  • Detection of flame retardants based on presence of specific elements
  • High resolution images of fibers, including cross-sections
  • Medical textiles
  • Wearable technology
EDS Sn-C Standard Spectrum
EDS Sn-C Standard Spectrum
EDS Sn-C Standard Electron
EDS Sn-C Standard Electron

  • Based on the idea that accelerated electrons in a vacuum behave similarly to light – travelling in linear direction.
  • Electric and magnetic fields replace glass lenses and mirrors as used in optical microscopy.
  • Wavelength is a major factor in resolution – the shorter the wavelength of an energy source, the greater the resolving power.
  • Electrons have a wavelength of about 100,000 times smaller than light.
  • Secondary electron (SE) detectors provide topographical information; Back-scattered electrons (BSE) provide information on composition.
  • Cathodoluminescence provides optical properties of nanostructures; Images can combine more than one type of detector information
  • Samples must be conductive; non-conductive materials can be sputter-coated with a fine layer of a conductive material to improve observation with SEM

Contact Information

Laboratory Location

NCSU, Wilson College of Textiles
TECS Department
1020 Main Campus Dr.
Centennial Campus R 2126
Raleigh, NC 27606

Lab Manager

Birgit Andersen
Research Assistant & Lab Manager
NC State, Wilson College of Textiles
TECS Department
Room 3127
1020 Main Campus Dr.
Raleigh, NC 27606

Office: 919-515-6590
Room: 3127

Email: bsanders@ncsu.edu

Responsible for Lab:
Birgit Andersen
Phone: 919.515.6590
Birgit_Andersen@ncsu.edu

Department Head

Dr. Jeffrey Joines

Email: jjoine@ncsu.edu
P: 919-513-4188

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