Infrared technique for the measurement of structural changes during the orientation process in polymers

Koenig, J. L.; Cornell, S. W.; Witenhafer, D. E.

doi:10.1002/pol.1967.160050206

Cited by 65 publications

(18 citation statements)

References 6 publications

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“…Both terms are equal and proportional to the total amount of the absorbing dipoles in the sample. [17,18] Compared to Fraser's model, which is interpreted as an imaginary fraction of completely oriented polymer chains in relation to a non-oriented fraction, our developed extended model shows the proportions between three completely oriented fractions along the x, y, and z-axes. In analogy to Equation (6a-c) this can be described in the form of three particular P 2 -Legendre functions on a unit sphere, generally called a pole sphere.…”

Section: Extension Of Fraser's Function To a Model For Calculating Ormentioning

confidence: 99%

“…Alternatively, the tilted film technique can be used as long as the correction procedures for the absorbance in film thickness direction are not ignored. [17] The term (A x þ A y þ A z )/3 is known as the structural absorbance (A 0 ) [17,22] and this reduced factor can be replaced in Equation (13). In analogy to the Fraser's function it is necessary to implement the factor D 0 þ2…”

Section: Extension Of Fraser's Function To a Model For Calculating Ormentioning

confidence: 99%

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Characterizing the Three‐Dimensional Orientation in Polymers using FT‐IR Spectroscopy with Linear Polarized Light

Brüll¹,

Maria²,

Rode³

2010

Macro Chemistry & Physics

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The quantity of absorbance of linear polarized light depends for a given wavelength on the angle between an absorbing transition moment vector and the electric vector of the polarized light. Fraser used this relationship to interpret the infrared dichroism in axially oriented polymers. This model can be extended to calculate the orientation in three dimensions by transforming the Fraser's equation into a P2‐Legendre polynomial. As a result the orientation in three directions—fx, fy, and fz—can be calculated directly from the individual absorbances measured with an electric vector along the axes of interest, the structural absorbance A0 of the sample, and the angle of the transition moment vector in reference to the chain axis. Applying the f values into ‘Hermans’ Orientation function', it becomes possible to calculate the average angle of the chain axis with reference to the axes of interest.

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Section: Extension Of Fraser's Function To a Model For Calculating Ormentioning

confidence: 99%

Section: Extension Of Fraser's Function To a Model For Calculating Ormentioning

confidence: 99%

Characterizing the Three‐Dimensional Orientation in Polymers using FT‐IR Spectroscopy with Linear Polarized Light

Brüll¹,

Maria²,

Rode³

2010

Macro Chemistry & Physics

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“…The peak area of isotropic film was calculated by IR trichroic measurement. 16 Bands at 725, I 720, and 1375 cm -i were selected for the three transitional moments mutually perpendicular to each other ( Figure 2). From these peaks, orientation of the pyromellitimide ring could be calculated.…”

Section: Effects Of Curing On Molecular Orientationmentioning

confidence: 99%

Effects of Thermal Curing on the Structure of Polyimide Film

Kim

Park

1998

Polym J

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ABSTRACT:The effects of thermal curing method on degree of imidization, molecular orientation, and chain ordering of the 4,4-oxydiphenylene pyromellitimide (PMDA--ODA) were investigated. Three different thermal curing methods were chosen in this study; two casts of polyamic acid on silicon wafer were isothermally cured at 200°C for 3 h (l-200) and 300°C for 3 h (l-300) respectively, and the other one was cured in step manner (S-300): I00°C for 1 h, 200°C for 1 h, and finally 300°C for I h. The degree of imidization was highest in the 1-300 and lowest in the S-300, demonstrating that the amount of solvent and degree of imidization at each stage of the curing cycles significantly affect the final degree of imidization. The degree of in-plane orientation was found highest for the S-300 and lowest for the 1-300. This suggests that the in-plane orientation decreases with increase of the chain immobilization. This chain ordering was found to be easily induced for the 1-300 among the three cured films. In the 1-300, the chains in the film are sparsely packed and ordering by the diffusion of polymer chians occurs most easily.KEY WORDS 4,4-Oxydiphenylene Pyromellitimide / Degree of Imidization / Molecular Orientation / Chain Ordering / In recent years, much attention has been directed to aromatic polyimide films, widely used as high-temperature insulators and dielectric coatings, adhesives, matrices, and alignment layer films for liquid crystal display. 1 • 2 The traditional synthetic route for these materials is two steps, the synthesis of poly(amic acid) (PAA) and subsequent thermal or chemical imidization (curing) of the PAA. 1 In preparation of the polyimide films, thermal imidization is generally used as the second step. Thermal imidization involves the simultaneous loss of solvent, cyclization of amic acid group to form imide, and both intra-and inter-molecular structure evolution. 3 • 7 -12 Regulation of the conditions on thermal imidization provides a wide spectrum of properties. Thus, understanding the effects of thermal curing method on the structure of the resulting polyimide film is very important to control the microstructure of the polyimide formed and to ensure final properties. However, a comparison of the degree of imidization, molecular orientation, and chain ordering among the polyimide films prepared by thermally different curring methods has not been made.This article studies the effects of thermal curing method on the structure of the polyimide films interfaced with silicon substrate. Three different curing methods were taken as follows; (i) isothermal curing at 200°C for 3 h (1-200), (ii) isothermal curing at 300°C for 3 h (1-300), and (iii) step curing (S-300) which consists of three steps: isothermal heating at 100°C for 1 h followed by isothermal heating at 200°C for 1 h, and then isothermal heating at 300°C for l h. EXPERIMENTAL MaterialsPyralin (Du Pont), a mixture of polyamic acid (4,4'-oxydiphenylene pyromellitamic acid), l-methyl-2-pyrrot To whom all correspondence should be addressed.lido...

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“…Previous studies for drawn polymers using the method were mainly based on quantitative analyses concerning the relative orientation of the polymer chains. Most of such studies were carried out on synthetic polymers, for example, polyethylene (Stein and Norris 1956;Onogi and Asada 1967;Koenig et al 1967;Read and Stein 1968;Karacan 2006), polypropylene (Samuels 1965;Shigematsu et al 2001), poly(ethylene terephthalate) (Liang and Krimm 1957;Dulmage and Geddes 1958;Lofgren and Jabarin 1994;Radhakrishnan and Kaito 2001;Kandilioti et al 2004), nylon 6 (Sibilia 1971), polyamide (Vasanthan 2005), poly(vinyl chloride) (Voyiatzis et al 2000), poly(trimethylene terephthalate) (Lee et al 2000), poly(methyloctadecylsilylene) (Kaito et al 1999), poly(3-alkylthiophenes) (Gustafsson et al 1991), poly(aryl ether ether ketone) (Voice et al 1993) and isotactic polystyrene and poly(2,6-dimethylphenylene oxide) blends (Dikshit and Kaito 2003). As for cellulose, not so many quantitative investigations have been made except studies on orientation of drawn cellulose fibers (Smith et al1963;Siesler et al 1975), on hydrogen bonding in cellulose II (Š turcová et al 2003) and on cellulose derivatives and synthetic polymers blends (Park et al 2005), since many cellulose researchers were required to determine the chain conformation and the crystalline structure (Mann and Marrinan 1958;Tsuboi 1957;Liang and Marchessault 1959a, b;Marchessault and Liang 1960;Liang and Marchessault 1960) and to assign the absorption bands (Tsuboi 1957;Liang and Marchessault 1959a, b;Marchessault and Liang 1960;…”

Section: Introductionmentioning

confidence: 99%

Molecular orientation in the Nematic Ordered Cellulose film using polarized FTIR accompanied with a vapor-phase deuteration method

2010

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Previously, the authors reported ''Nematic Ordered Cellulose (NOC)'' that is a well-ordered state of b-1,4-glucan chains without exhibiting typical X-ray diffraction patterns of any cellulose polymorphs Kondo et al. 2001;Kondo 2007). The NOC was prepared by stretching water-swollen gel-like films at the draw ratio of 2.0 to provide highly oriented b-1,4-glucan molecular chains of cellulose, which was proved by the high resolution TEM observation. In this paper, a detailed study of the unique ordered state of the NOC was attempted to characterize orientation of the main chains as well as the OH groups of molecules using polarized FTIR accompanied with a vapor-phase deuteration method. The dichroic analysis suggested that the main chains were fairly oriented in the stretching direction whereas the OH groups remained unoriented. The disordered state of the OH groups regardless of the oriented state for the main chain may hinder the oriented crystallization during the preparation of NOC films.

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Infrared technique for the measurement of structural changes during the orientation process in polymers

Cited by 65 publications

References 6 publications

Characterizing the Three‐Dimensional Orientation in Polymers using FT‐IR Spectroscopy with Linear Polarized Light

Characterizing the Three‐Dimensional Orientation in Polymers using FT‐IR Spectroscopy with Linear Polarized Light

Effects of Thermal Curing on the Structure of Polyimide Film

Molecular orientation in the Nematic Ordered Cellulose film using polarized FTIR accompanied with a vapor-phase deuteration method

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