JPS63243836A - Method for measuring surface orientability of high-polymer material and instrument used therefor - Google Patents

Abstract

PURPOSE:To efficiently and exactly measure the surface orientability of a high-polymer material having various shapes and smooth surface by projecting the light past a polarizer to the smooth surface of the high-polymer material from an approximately perpendicular direction and measuring the wavelength dispersion of the reflectivity of the polarized light. CONSTITUTION:The light past the polarizer is projected to the smooth surface of the high- polymer material from the approximately perpendicular direction. This operation is repeated by rotating the polarizer and the wavelength dispersion of the reflectivity of the polarized light is measured by a detector. The result of the measurement is converted to the wavelength dispersion of a refractive index n or absorption coefft. K in accordance with the equation I and the equation II or the equation III [where omega, omega0 are the frequencies of the light, R(omega) is the reflectivity at the frequency omega]. The peak value of the absorption coefft. K or the difference between the max. value and min. value in the wavelength dispersion of the refractive index n is detected and the absorption intensity in the respective polarization directions is determined. An orientation coefft. f is determined in accordance with the equation IV and the equation V (where D is the ratio of the absorption intensity, D0=2cot<2>gamma, gamma is the angle between the transition moment and high-polymer chain) from the resulted absorption intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel method for measuring surface orientation of polymeric materials and an apparatus used therefor.

(2) More specifically, the present invention utilizes light reflection on the surface of polymeric materials to efficiently and accurately measure the surface orientation of not only films but also polymeric materials such as thick sheets and molded products. The method of doing so, and the equipment used.

Conventional technology Measuring the surface orientation of polymeric materials in order to accurately understand their properties and functions is extremely important for the development of functional polymeric materials and the development of new applications. .

Conventionally, methods for measuring orientation in polymeric materials include X-ray diffraction, infrared dichroism, dye dichroism, polarized fluorescence, birefringence, sonic modulus However, all of these methods are for evaluating the average orientation of the entire sample, and are not methods for evaluating the surface orientation.
The X-ray diffraction method evaluates only the orientation of crystalline regions, the dyeing dichroism method and polarized light fluorescence evaluate only the orientation of amorphous regions, and the infrared dichroism method and other methods evaluate absorption spectra. The method based on this method requires a thin film as the polymer material, and has problems such as being inapplicable to thick sheets or molded products.

As described above, the conventional methods are not necessarily satisfactory as methods for measuring the surface orientation of polymeric materials. There has been a desire to develop a method for efficiently and accurately measuring orientation.Problems to be Solved by the InventionThe present invention addresses the following demands: The purpose of this invention is to provide a method for efficiently and accurately measuring the surface orientation of a material, and an apparatus for use therein.

Means for Solving the Problems In order to achieve the above object, the inventors of the present invention have conducted extensive research and have developed a method for projecting light with different polarization directions from a direction approximately perpendicular to the surface of a polymeric material having a smooth surface. The surface orientation can be efficiently determined by measuring the wavelength dispersion of the polarized reflectance, determining the refractive index or extinction coefficient from this measurement result, and determining the surface orientation function from the anisotropy. Measuring scales,
The wavelength dispersion of the polarized light reflectance can be easily measured by using a specific device.

That is, the present invention provides a method for measuring the surface orientation of a polymeric material with a smooth surface, which includes: 0) projecting light through a polarizer onto the smooth surface of the polymeric material from a substantially perpendicular direction; a step of measuring wavelength dispersion, (b) a step of rotating the polarizer and repeating the above (a) using light with a polarization direction different from the above (a); and the formula n==(1-R)/(1+R-2aosφVT)...(
ri) or k == -28inφJY/(1+R-2cos
(v'π) - (110 (however, ω, ω0 is the frequency of light, R ((b) is the reflectance at frequency ω (=)) (- Therefore, it changes to wavelength dispersion due to refractive index n or extinction coefficient, The step of detecting the difference between the maximum value and the minimum value in the wavelength dispersion of the refractive index n and calculating the absorption intensity and A↓ for each polarized light. From the cherry blossoms 4 and A detected in step (e), the formula % formula% and formula f = (D-1) (Do +2) / (D+2) (D,
-1) ... (to) (where 4=icot2r' γ is the angle between the transition moment and the polymer chain) A method for measuring surface orientation, comprising the step of determining an orientation function f according to A polarizer 1 whose polarization plane can be rotated to obtain light with different polarization directions, and a rotatable plane mirror 2 which receives the light that has passed through the polarizer 1 and projects the polarized light onto the surface of the material to be measured 3.
, provides a surface orientation measurement device for a polymeric material having a structure including a detection organ for measuring wavelength dispersion from a material to be measured 3.

The present invention will be explained in detail below.

In the method of the present invention, the polymeric material used to measure the surface orientation may be any polymeric material that has a smooth surface and absorbs in a measurable wavelength region.
There are no particular limitations; for example, it can be applied to materials in the form of seeds, such as films, thick sheets, and molded products.

As a polymer material having an expression surface, for example, the center line average roughness RIM:) at a cutoff value of 0.8n is j
A material having a smooth surface with an Ra value of 0.1 p or less at the cutoff value D and Q B mm is preferably used.

On the other hand, the wavelength range of light used for measurement is applicable from the ultraviolet to the far infrared region, and the orientation function represented by the above general formula (g), which indicates the degree of surface orientation, has a constant: The angle between the transition moment in the material to be measured and the polymer chain is used, but the transition may be an electronic transition or a vibrational transition.

Next, the measurement method of the present invention will be explained with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an example of the structure of an apparatus used in the measurement method of the present invention. 1. After making the desired polarization direction by inputting two components, this polarized light is transmitted to the smooth surface of the material to be measured 3 (2. The angle of incidence is within 20" (approximately 2. Measure the projected chromatic dispersion from the vertical direction.

Measure long dispersion.

In addition, for transparent or translucent stock, the measured reflectance (=
, multiple reflections from the back surface contribute, so
For example, a known method [Journal of Physical Society Japan (J.

Ph7a, Soc, Jpn,) J Volume 16, No. 2
525 (1961)], it is important to remove the influence of multiple reflections and calculate the reflectance from the surface. Figure 2 shows multiple reflections measured using two types of light with different polarization directions. 2 is a spectrum diagram showing an example of wavelength dispersion of polarized light reflectance after correction of reflection, where the horizontal axis is wavelength and the vertical axis is polarized light reflectance.

Next, the results of the wavelength dispersion of the polarized light reflectance obtained using two types of light with different polarization directions are as follows:
Formula and formula n=(1-R)/(t+R-2cosφ4./f)
-(II) or k = -28i ntlsJR/(1+ R-2CO8
吋f＞−([) (where ω, ω. is the frequency of light, R (→ is the reflectance at the frequency ω) (2) Therefore, the refractive index n or extinction coefficient is converted into wavelength dispersion. Formulas (II) and (2) are the so-called Fresnel equations.

Examples of wavelength dispersion spectra for the refractive index n and extinction coefficient, which are the optical constants obtained in this way, are shown in FIGS. 3 and 4, respectively. In each figure, solid lines and broken lines are
These correspond to the solid line and broken line in the wavelength dispersion spectrum of polarized light reflectance in FIG. 2, respectively.

Next, detect the peak value of the extinction coefficient obtained as described above or the difference between the maximum value and the minimum value of the wavelength dispersion of the refractive index n, and calculate the absorption intensities A7 and A for each polarization direction. After finding the ratio of A and Ai according to the formula % formula % (7), the absorption intensity for each polarized light is calculated from the wavelength dispersion spectrum of the refractive index n or extinction coefficient, for example, by As shown in Figure 5, it can be detected by finding the value of ↓.

FIGS. 5(a) and 5(b) are model diagrams of wavelength dispersion spectra with respect to refractive index n and extinction coefficient, respectively.

The above orientation function can be expressed as the formula % (where 〉 means the spatial average), where θ is the angle between the polymer chain and the stretching direction, so the above formula ('I) can be expressed as: When the obtained orientation function is 1, it indicates that the polymer chains are completely oriented in the stretching direction, whereas when it is 0, it indicates that there is no orientation.
In the case of , the polymer chains are completely oriented in the direction perpendicular to the stretching direction.

Note that the operation of processing the wavelength dispersion of the polarized light reflectance obtained by the detector 5 to obtain the orientation function is preferably performed automatically (two times) by a computer.

Effects of the Invention According to the measuring method of the present invention, the surface orientation of polymeric materials having various shapes such as films, thick sheets, and molded products can be efficiently and accurately measured. This measurement method is extremely useful in the development of functional polymer materials and the exploration of new applications.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these examples in any way.

Example A 0.2 nm thick film of polyethylene terephthalate (PET) stretched 5.3 times at 80° C. was used as the material to be measured. This one has a cutoff value of 0.8
Ra value at ff is 0.1μm1 Cutoff value is 0.0
The Ra value at 8 m is 0.01 μm, and the surface is extremely smooth. Moreover, the apparatus shown in FIG. 1 was used to measure the surface orientation.

First, make sure that the plane of polarization and the stretching direction of the sample are parallel (=
Adjust the polarizer 1, project the light that has passed through the polarizer 1 onto the surface of the sample 3 via the plane mirror 2, send the reflected light to the detector 5 via the plane mirror, and measure the polarization reflectance. The wavelength dispersion of was determined.

Next, make sure that the polarization plane and the stretching direction of the sample are perpendicular (=
The polarizer 1 is adjusted, and the light that has passed through the polarizer 1 is projected onto the surface of the sample 3 in the same manner as described above. These results are shown in Figure 2.

FIG. 2 is a wavelength dispersion spectrum diagram of polarized light reflectance. In the figure, the solid line indicates the case where the plane of polarization is parallel to the stretching direction of the sample, and the broken line indicates the case when the plane of polarization and the stretching direction of the sample are perpendicular. Note that these spectral diagrams are obtained after correction using the reference light and correction for multiple reflections.

From the wavelength dispersion data of the polarized reflectance, the formula (I
), Ql) and string), the wavelength dispersion in the refractive index n and extinction coefficient is determined, and the spectra thereof are shown in FIGS. 3 and 4, respectively. In each figure, the solid line and the broken line are the data corresponding to the solid line and the broken line in FIG.

As can be seen from Figure 4, 280-300 nm and 24
Two absorption bands were observed in the wavelength range around 0 to 25 Onm. This is the first π8− of the benzene ring of PET, respectively.
It is assigned to the π transition and the second π-π transition.

* The orientation function was determined using the theoretical value of 22.8' for the angle γ between the transition moment of the second π-π transition and the polymer chain.

From the peak value of this extinction coefficient, the absorption intensity ratio D('?/
Am) was found to be 3.35, υ, and the orientation function found from this value and the above-mentioned γ value was 0.57. On the other hand, when the absorption intensity ratio D (2/At) was calculated from the difference between the maximum value and the minimum value of the refractive index n, it was found to be 5.21, and the orientation function f calculated from this value and the above γ value. was 0.76.

Although the difference in these orientation functions is due to the overlapping absorption bands, it was found that the surface of the stretched PET film was well oriented in the stretching direction.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the structure of an apparatus used in the present invention. In the figure, reference numeral 1 is a polarizer, 2.4 is a plane mirror, and 5 is a detector. Figures 2, 3, and 4 are wavelength dispersion spectra of polarized reflectance, refractive index, and extinction coefficient in Examples, respectively. ) and (b) are model diagrams showing how to obtain absorption intensity from wavelength dispersion of refractive index and extinction coefficient, respectively.

Claims (1)

[Claims] 1. A method for measuring the surface orientation of a polymeric material with a smooth surface, including (a) projecting light through a polarizer onto the smooth surface of the polymeric material from a substantially perpendicular direction, and detecting the polarized light reflection. (b) rotating the polarizer and repeating (b) using light with a polarization direction different from that in (b); (c) (b)
The measurement results of R)(
However, ω, ω_0 are the frequencies of light, and R(ω) is the frequency ω
the peak value of the extinction coefficient R or the maximum and minimum values of the wavelength dispersion of the refractive index n obtained in step (d) (b) (e) From A_■ and A_⊥ detected in step (d), the formula D=A_■/A_⊥ and the formula f are obtained. =(D-1)(D_0+2)/(D+2)(D_0-
1) (where D_0=2cot^2γ, γ is the angle formed between the transition moment and the polymer chain) A method for measuring surface orientation, comprising the step of determining an orientation function f according to the following. 2. Polarizer (1) capable of rotating the plane of polarization to obtain light with different polarization directions; receives the light that has passed through the polarizer (1) and projects the polarized light onto the surface of the material to be measured (3) A plane mirror (2) is provided to send the reflected light from the material to be measured (3) to the detector (5). An apparatus for measuring surface orientation of a polymeric material having a structure comprising a detector (5) for measuring wavelength dispersion.