JPS60208336A - Polymer membrane exhibiting thermoreversible clouding point phenomenon, and production thereof - Google Patents

Abstract

PURPOSE:To obtain a polymer membrane exhibiting thermoreversible clouding point phenomenon, and expected to be useful as a temperature indicator, a temperature-sensitive light-shielding material, etc., by crosslinking a film of a specific polycrylamide derivative. CONSTITUTION:The amide group of apolyacrylamide is methylolated, and the methylol group is aminated with a secondary amine (pyrrolidyl or piperidyl) to obtain a polyacrylamide derivative composed essentially of the recurring unit of formula (R is pyrrolidyl or piperidyl). The polymer is formed in the form of film, dried, and crosslinked by heating in dry state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polymer membrane exhibiting a thermoreversible pointless phenomenon and a method for manufacturing the same.

More specifically, the present invention relates to a polyacrylamide derivative which exhibits a pointless phenomenon, which is obtained by methylolizing the amide group of polyacrylamide and further reacting the methylol group with a secondary amine, pyrrolidyl group or piperidyl group. A polymer membrane characterized by exhibiting a thermoreversible cloud point phenomenon in which a molecular compound is crosslinked after film formation, and the polymer compound is cast as an aqueous solution onto a flat plate, air-dried, and then cross-linked by dry heating. The present invention relates to a method for producing a polymer membrane exhibiting a thermoreversible pointless phenomenon characterized by:

The pointless phenomenon usually refers to a phenomenon in which a transparent aqueous solution of a certain type of compound becomes cloudy due to a rise or fall in temperature, but the polymer membrane of the present invention has a crosslinked polymer that makes up the membrane. Despite being insoluble in water, it is observed that it exhibits a reversible pointless phenomenon in which it becomes cloudy at a certain temperature ([1 point) or below] and becomes transparent below this temperature. Therefore, the polymer film of the present invention is expected to be applied as a temperature display material or a temperature-sensitive light shielding material.

The polymer membrane of the present invention is produced by methylolizing the amide group of polyacrylamide, as shown in detail in Reference Examples 1 and 2.
Furthermore, the material is a polyacrylamide derivative that is aminated with a secondary amine, but the material contains
A small amount of unreacted methylol groups remain, and by crosslinking with the surrounding amide groups, a water-insoluble polymer film is formed that retains the reversible pointless phenomenon of the material. There is.

The polymer membrane of the present invention is produced by casting a 2-20% aqueous solution of polyacrylamide derivative as a raw material onto a Teflon plate,
After naturally drying this at room temperature for at least 24 hours, place it in a thermostatic dryer at a temperature of 60 to 90 degrees Celsius for 15 to 20 minutes depending on the temperature.
Produced by dry drying for 80 minutes. 85°
If heated for 30 minutes or more at temperatures above C, the film will be colored yellow, making it difficult to detect no spots.

There are other methods for forming a water-insoluble film after casting onto a film forming plate, such as radiation irradiation and infrared heating, but the method of the present invention is extremely simple and safe, using dry heating. It is characterized by

The polymer membrane of the present invention is formed by crosslinking the material, which is a polyacrylamide derivative, as described above, and its zero score is approximately 0"CC higher than that of the material.

The present invention will be further explained by referring to the following reference examples and examples. will be explained in detail.

Reference Example 1 1.4 g (0.02 mol) of polyacrylamide is added to a 1001RI flask containing 5 Q ml of water and sufficiently dissolved. Add NaOH aqueous solution to this and PHI
I to 12, paraformaldehyde 0.72 g (
0,024 mol) and stirred at room temperature for 1 hour to carry out the methylolation reaction. Next, 2 m of piperidine (0,02
4 mol) was gradually added and heated at room temperature for 1 hour, then at 4o''C.
Stir for 1 hour to react. As the reaction progresses, a white precipitate is formed. The product is precipitated into acetone, filtered and dissolved in water at 10°C. Precipitation with acetone, filtration, and dissolution with water are repeated three times, and the resulting polymer is dissolved in water and freeze-dried.

A white bulky polymer is obtained. As a result of the measurement, the zero point was 18°C.

Reference Example 2 Add 1.4 g (0.02 mol) of polyacrylamide to a 100 m flask containing 5 Q ml of water and dissolve thoroughly. Add KOH aqueous solution to this and PHII~4
- 12, paraformaldehyde 0.72 g (0
, 024 mol) and stirred at room temperature for 1 hour to carry out the methylolation reaction. Next, pyrrolidine 1.8 d (
0,024 mol) was gradually added, and the mixture was further heated at room temperature for 1 hour.
Stir and react at 50°C for 1 hour. The reaction solution is poured into acetone to precipitate the product, filtered and dissolved in water.

Precipitation with acetone, filtration, and dissolution with water are repeated three times, and the resulting polymer is dissolved in water and freeze-dried. A white bulky polymer is obtained. As a result of the measurement, the zero point was 42°C.

Example 1 A 596 aqueous solution of the polymeric compound consisting of "niboIJ-N-piperidylmethylacrylamide" obtained in Reference Example 1 was cast onto a Teflon membrane plate, air-dried for 24 hours, and then heated at 80° The pass rate is in a constant temperature dryer at C for 30 minutes.

FIG. 2 shows the infrared absorption vector (IR) of the produced polymer film. Curve ■ shows the film before heat treatment. Curve ■ shows the film after heat treatment. 1300.1051 by heat treatment
It can be seen that the methylol group of 05O is reduced, indicating that crosslinking is progressing.

Example 2 A 5% aqueous solution of the polymer compound obtained in Reference Example 2 consisting essentially of polyIJ-N-pyrrolidylmethylacrylamide was cast onto a Teflon membrane plate, air-dried for 24 hours, and then It was then heat treated at 80°C for 30 minutes in a constant temperature drying mold. The temperature of the obtained film was 53°C.

[Brief explanation of drawings]

FIG. 1 is a graph showing the results of key measurements of the light transmittance at a wavelength of 500μ of a polymer film substantially made of IJ-N-piperidylmethylacrylamide, and FIG. It is a graph showing IR of a polymer membrane made of -N-piperidylmethylacrylamide. 7- V′7]] side

Claims (1)

[Claims] A polyacrylamide derivative exhibiting a thermoreversible pointless phenomenon and consisting essentially of repeating units represented by the following general formula: % (R in the formula represents a pyrrolidyl group or a piperidyl group) A polymer membrane exhibiting a thermoreversible pointless phenomenon characterized by being formed into a membrane and then crosslinked. 2 A polyacrylamide derivative consisting essentially of repeating units represented by the general formula % (R in the formula represents a pyrrolidyl group or a piperidyl group) is formed into a film, then dried and subjected to a dry heat treatment. A method for producing a polymer film that exhibits a thermoreversible pointless phenomenon.