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Elucidating Structure-Property-Processing Relationships with On-Line Raman

IP.com Disclosure Number: IPCOM000011712D
Publication Date: 2003-Mar-12

Publishing Venue

The IP.com Prior Art Database

Related People

R. Guenard: AUTHOR [+6]

Abstract

Synthetic polymer development is becoming increasingly more sophisticated with improved modeling, highly specific catalysts, enhanced processing and materials blending to name a few. These advancements in polymer design commensurately require highly selective measurements on the molecular level to obtain correlation between polymer structure, processing variables and end-use properties. Coupling the powerful fundamental attributes of Raman spectroscopy with on-line sampling flexibility is invaluable in obtaining this type of structural information. A case study showing the utility of on-line Raman in the development of nylon 6 fibers will be presented.

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1

   Elucidating Structure-Property- Processing Relationships of Polymer Fibers with On-Line Raman

Rob Guenard, Rajesh P. Paradkar, Anne Leugers, Gerry Billovits and John Warakomski

   The Dow Chemical Company Corporate Research and Development Analytical Sciences

RDG PITTCON 2003 March 13, 2003

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2Research Goals

* Study molecular structure development in fiber spinning process of a nylon 6 alloy material.

* Correlate molecular structure with processing conditions and fiber properties.
* Provide analytical knowledge to researchers for product optimization.

* Provide knowledge to modelers in evolution towards simulated R&D.

RDG PITTCON 2003 March 13, 2003

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3Structure Property Processing Relationships

   Fiber properties - tensile modulus - dyeability
- structural stability - appearance, etc.

Molecular Structure & morphology
- composition
- tacticity
- crystallinity
- orientation, etc.

     Processing - melt temperature - spinning rate
- draw ratio
- thermal history, etc.

RDG PITTCON 2003 March 13, 2003

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4On-line Raman-Advantages

*Compositionally rich information about crystalline AND amorphous phases of the polymer sample.

*Good optical sampling for single filaments with various cross sections or yarns.

*Fast algorithms for streaming data enabling process control

*Polarized Raman can be used to estimate relative orientation.

RDG PITTCON 2003 March 13, 2003

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5Polymorphism in Nylon 6

* At least two main polymorphs of PA6 have been identified and relatively well characterized using XRD
* Formation depends on the crystallization conditions

Nylon Plastics Handbook
M.I. Kohan (editor) Hanser Publishers 1995, Page 370

RDG PITTCON 2003 March 13, 2003

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6

Morphological Changes with Moisture

*Moisture disrupts inter-chain hydrogen bonding, lowers Tg
*Increased chain mobility allows the PA6 chains to adopt lower energy planar zigzag conformation

C

N H

N H

O

H

O

H

As Spun control

Autoclave

Water

H

O

H

O

C

RDG PITTCON 2003 March 13, 2003

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7Polymorphism in Nylon 6

Normalized intensity

5000

4000

3000

1635

γ-form

1080

1120

921.8

962.3

1298 12751167 1232 13661378

1440

2000

1000

1467

1126

1635

α-form

s s

1062

931.6

800 1000 1200 1400 1600 1800

12011168

13061280

1376

1444

0

Raman Shift (cm-1)

Mode α-form γ-form

δ(CH2) 1444 cm-1, 1423 cm-1, 1439 cm-1 1467 cm-1, 1481 cm-1 t(CH2) 1307 cm-1, 1280 cm-1 1298 cm-1 , 1275 cm-1 ν(CC) 1127 cm-1 1120 cm-1
ν(C-CO) 933 cm-1 922 cm-1

RDG PITTCON 2003 March 13, 2003

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8Quiescent Crystallization of Nylon 6

1305 1109 1076 1440 1649

1062 933

1440

164010761062 11...