- Email: [email protected]
Copolymerization of ethylcyanoacrylate with methyl vinyl ketone
Copolymerization of ethylcyanoacrylate with methyl vinyl ketone K. M a r u y a m a * , Y. T s u s h i m a * , T. K u r a m o c h i * , M . I b o n a i * a n d K. N a g a s a w a + (*Kogakuin University/+Taoka Chemical Industries, Ltd, Japan)
Copolymerization of ethylcyanoacrylate (ECA, M1) with methyl vinyl ketone (MVK, M2) was studied. Monomer reactivity ratios of ECA determined by the Fineman-Ross method were r7 = 2.67 and r 2 = 0. 14. A small portion of MVK enhanced the heat resistance property of the copolymers. Key words: ethylcyanoacrylate; methyl vinyl ketone; copolymerization
a-Cyanoacrylates, which are anionically polymerized in the presen~:e of weak bases such as water or amine, are used industrially as instant adhesives. One drawback of poly-a-cyanoacrylates is their tendency to soften and become plastic at approximately 100°C, with a consequent loss of adhesive properties. Research in recent years has sought to improve heat resistance. The purpose of this study was to compare polymerization of conventional a-cyanoacrylate with a-cyanoacrylate to which a highly-reactive vinyl ketone has been added, and which is also capable of polymerization.
Experimental details Ethylcyanoacrylate (ECA), Taoka Chemical Co.. Ltd.) and methyl vinyl ketone (MVK), Tokyo Chemical Corporation) were used in this experiment. The EtA and MVK, in the solvent tetrahydrofuran (THF), were polymerized at room temperature with water being the weak base. The polymers formed were precipitated from the THF solution with methanol. Homopolymers of MVK were then formed, initiated by sodium methoxide. The homopolymers formed were precipitated from the solvent using water which had been purified in an ion exchange resin. The intrinsic viscosity, r/, of the polymers in acetone solvent were determined. Table i shows the conditions of polymerization and the intrinsic viscosities. Infrared spectra were obtained with the IR-435 instrument developed by Shimadzu Seisakusho, Ltd. I H - N M R spectra were measured with JNM-PMXr0si produced by JEOL Ltd. Gel permeation chromatography was performed with an A-803 column produced by Showa Denko Ltd.. and a differential 0413-7496/89/030143-02
Table 1.
Copolymerization of ECA with MVK
Specimen No.
ECA MVK Yield (moll -1) (moll -1) (%)
Intrinsic viscosity, r/(dlg-1) 1
1
1.58
--
75
0.07
2 3 4 5 6 7 8 9
1.25 1.07 0.94 0.74 0.62 0.43 0.31 --
0.53 0.85 1.04 1.41 1.59 1.91 2.13 2.37
52 45 40 35 30 24 19 43
0.12 0.24 0.32 0.34 0.42 0.38 0.32 0.02
1acetone at 30°C; solvent; THF. initiator; He0 (Nos 1-8), CH3ONa (No. 9)
refractometer detector (Shodex RISE-31 ). The softening point and tensile shear strength of the polymers were measured. The softening point was measured using a thermomechanical analyser, model MP-S2. A rigid pvc fihn of 0.025 cm thickness was used as an adherend during measuremen! of tensile shear strength. Prescribed amounts of both IX_'Aand MVK were adhered to the PVC film and the tensile shear strength was measured using an autograph S-100 (Shimadzu Seisakusho Ltd.) following curing of the adhesive for five days at room temperature.
Results and discussion Infrared analysis of the ECA polymer indicated absorption by C C O O C H 2 C H 3. C-=N, and CH2CH 3 groups at frequencies of 125(I cm -t and 17411cm -I,
$03.00 © 1989 Butterworth 8" Co (Publishers) Ltd INT.J.ADHESlON AND ADHESIVES VOL.9 NO.3 JULY 1989
143
2240 cm -I and 2990 cm -I, respectively. The NMR absorption by ECA polymer indicated the presence of CH3, CH2, and - O - C H ~ - bonds at chemical shifts of 1.2-1.7 ppm, 2.6-3.2 ppm, and 4.2-4.6 ppm, respectively. Infrared analysis of MVK polymer showed absorption by the > C = O and -CH~ groups at frequencies of 1165 cm -t, 1708 c m - ' , and 2990 cm -I, respectively. The NMR absorption by MVK polymer indicated the presence of CH 3, CH~, and CH groups at chemical shifts of 1.1-1.5 ppm, 2.0-2.4 ppm, and 3.2 ppm. respectively. Infrared analysis of ECA-MVK copolymers (ECA:MVK = 49 mo1%:51 mol%) indicated absorption by CCOOCH2CH 3, > C = O , - C = N , -CH2CH 3 and -CH~ groups at frequencies of 1250 cm -I and 1740-cm- t 1708 c m - J. 2240 c m - i, and 2990 c m - i respectively. The NMR absorption by ECA-MVK copolymer indicated the presence of CH3, CH~, CH and - O - C H , - bonds at chemical shifts of 1.2-1.6 ppm, 2.7-3.1 ppm, 3.8 ppm and 4.8-5.3 ppm, respectively. Gel permeation chromatography of the copolymer indicated the presence of only one peak. The copolymer, therefore, can be presumed to be of a single polymer ty,pe. It can be assumed that ECA and MVK copolymerized. Fig. I illustrates the dependence of copotymer composition on the feed ratio. The copolymer compositions were determined from the infrared and NMR spectra. The monomer reactivity, ratio of ECA (Mr) with MVK (M2) was determined by the Fineman-Ross method 2 in accordance with Fig. 1. The results are as follows: rl = 2.67 and r~ = 0.14. The Q-e values of ECA (Mi) and MVK (M 2) were calculated with these results: Ql = 9.68, Q2 = 0.69. el = 1.67 and e2 = 0.683. Table 2 shows the softening points and the adhesive strengths of the copolymers. The softening point rises as the MVK concentration increases, indicating that the rise in softening point results from the copolymerization of ECA and MVK, as well as from an
Table 2. strength
Softening points of polymers and adhesive
Specimen No.
ECA (feed molar fraction)
Softening point (°C)
Adhesive strength
(kg cm-2) ~ 10
1.00
160~
11
0.81
172 ~ 180
171
12 13 14 15 16 17
0.69 0.62 0.49 0.41 0.29 0.20
175 ~ 185 1 7 0 ~ 180 183~200 201 ~ 2 1 3 205~215 210~217
81 +__2 59__+ 5 54__+ 7 25__+8 12__+2 6 __+1 2__+ 1 --
~lap area = 0.4 cm 2 (2 cm x 0.2 cm); number of test pieces = 5
increase in molecular weight. Modes of failure for samples given in Table 2 were: No. 10. interfacial: Nos 11 and 12, cohesive and Nos 13-16, intrafacial. With sample No. 17 failure was interfacial and the strength was very low. As an alternative to applying a mixture of ECA and MVK monomers to PVC substrates in the assembly of adhesive bonds, the copolymers were also used as solution polymers in acetone. It was only with polvethvlcyanoacrylate that a joint strength (of 0.0c) kg cm -2) could be measured. In other cases the copolymers peeled from the adherend as the acetone evaporated. Conclusions The m o n o m e r reactivity, ratios for ECA and MVK were: rj = 2.67. and r~ = 0.14. F r o m these two values, the
values of Q-e were calculated: Q1 = 9.68, e I 1.67, and Q2 = 0.69, e~ = 0.68. The addition of MVK improves the heat resistance of E('A, but lowers adhesion. =
Acknowledgement
o L. o o O o o
._g X
0.5
0
This study was first published in the minutes of meeting No. 24 of the Adhesion Study Group of" the Japanese Adhesion Association in Osaka on 13 June,
//
1986.
References 1
"AdhesionHandbook" (The Japan Adhesion Association, Nikkan
2
Fineman. M. andRoas, S.D. JPolymSciS(1950) p259
3
Brandrup, J. and Immergut, E.H. (eds) "Polymer Handbook' (Interscience, 1966)
Kogyo Shimbunsha) (1980)
Authors I 0
0.5
Molar fraction cyonoacrylote in feed Fig. 1 Dependence of the copolymer composition on feed ratio: ©, determined by infrared spectroscopy; and A, determined by NMP spectroscopy
144
INT.J.ADHESION AND ADHESIVES JULY 1 9 8 9
Kazushi Maruyama. Yoshio Tsushima, Tomohiro Kuramochi and Masaru Ibonai are with the Department of Industrial Chemistry, Kogakuin University 2665-1, Nakano-machi, Hachiouji-shi, 192, Japan. Kouji Nagasawa is with Taoka Chemical Industries, Ltd., 2-I 1 Nishimikuni, 4-chome, Yodogawa-ku, Osaka-shi, 532, Japan. Correspondence should be addressed to M. lbonai.
Copolymerization of ethylcyanoacrylate (ECA, M1) with methyl vinyl ketone (MVK, M2) was studied. Monomer reactivity ratios of ECA determined by the Fineman-Ross method were r7 = 2.67 and r 2 = 0. 14. A small portion of MVK enhanced the heat resistance property of the copolymers. Key words: ethylcyanoacrylate; methyl vinyl ketone; copolymerization
a-Cyanoacrylates, which are anionically polymerized in the presen~:e of weak bases such as water or amine, are used industrially as instant adhesives. One drawback of poly-a-cyanoacrylates is their tendency to soften and become plastic at approximately 100°C, with a consequent loss of adhesive properties. Research in recent years has sought to improve heat resistance. The purpose of this study was to compare polymerization of conventional a-cyanoacrylate with a-cyanoacrylate to which a highly-reactive vinyl ketone has been added, and which is also capable of polymerization.
Experimental details Ethylcyanoacrylate (ECA), Taoka Chemical Co.. Ltd.) and methyl vinyl ketone (MVK), Tokyo Chemical Corporation) were used in this experiment. The EtA and MVK, in the solvent tetrahydrofuran (THF), were polymerized at room temperature with water being the weak base. The polymers formed were precipitated from the THF solution with methanol. Homopolymers of MVK were then formed, initiated by sodium methoxide. The homopolymers formed were precipitated from the solvent using water which had been purified in an ion exchange resin. The intrinsic viscosity, r/, of the polymers in acetone solvent were determined. Table i shows the conditions of polymerization and the intrinsic viscosities. Infrared spectra were obtained with the IR-435 instrument developed by Shimadzu Seisakusho, Ltd. I H - N M R spectra were measured with JNM-PMXr0si produced by JEOL Ltd. Gel permeation chromatography was performed with an A-803 column produced by Showa Denko Ltd.. and a differential 0413-7496/89/030143-02
Table 1.
Copolymerization of ECA with MVK
Specimen No.
ECA MVK Yield (moll -1) (moll -1) (%)
Intrinsic viscosity, r/(dlg-1) 1
1
1.58
--
75
0.07
2 3 4 5 6 7 8 9
1.25 1.07 0.94 0.74 0.62 0.43 0.31 --
0.53 0.85 1.04 1.41 1.59 1.91 2.13 2.37
52 45 40 35 30 24 19 43
0.12 0.24 0.32 0.34 0.42 0.38 0.32 0.02
1acetone at 30°C; solvent; THF. initiator; He0 (Nos 1-8), CH3ONa (No. 9)
refractometer detector (Shodex RISE-31 ). The softening point and tensile shear strength of the polymers were measured. The softening point was measured using a thermomechanical analyser, model MP-S2. A rigid pvc fihn of 0.025 cm thickness was used as an adherend during measuremen! of tensile shear strength. Prescribed amounts of both IX_'Aand MVK were adhered to the PVC film and the tensile shear strength was measured using an autograph S-100 (Shimadzu Seisakusho Ltd.) following curing of the adhesive for five days at room temperature.
Results and discussion Infrared analysis of the ECA polymer indicated absorption by C C O O C H 2 C H 3. C-=N, and CH2CH 3 groups at frequencies of 125(I cm -t and 17411cm -I,
$03.00 © 1989 Butterworth 8" Co (Publishers) Ltd INT.J.ADHESlON AND ADHESIVES VOL.9 NO.3 JULY 1989
143
2240 cm -I and 2990 cm -I, respectively. The NMR absorption by ECA polymer indicated the presence of CH3, CH2, and - O - C H ~ - bonds at chemical shifts of 1.2-1.7 ppm, 2.6-3.2 ppm, and 4.2-4.6 ppm, respectively. Infrared analysis of MVK polymer showed absorption by the > C = O and -CH~ groups at frequencies of 1165 cm -t, 1708 c m - ' , and 2990 cm -I, respectively. The NMR absorption by MVK polymer indicated the presence of CH 3, CH~, and CH groups at chemical shifts of 1.1-1.5 ppm, 2.0-2.4 ppm, and 3.2 ppm. respectively. Infrared analysis of ECA-MVK copolymers (ECA:MVK = 49 mo1%:51 mol%) indicated absorption by CCOOCH2CH 3, > C = O , - C = N , -CH2CH 3 and -CH~ groups at frequencies of 1250 cm -I and 1740-cm- t 1708 c m - J. 2240 c m - i, and 2990 c m - i respectively. The NMR absorption by ECA-MVK copolymer indicated the presence of CH3, CH~, CH and - O - C H , - bonds at chemical shifts of 1.2-1.6 ppm, 2.7-3.1 ppm, 3.8 ppm and 4.8-5.3 ppm, respectively. Gel permeation chromatography of the copolymer indicated the presence of only one peak. The copolymer, therefore, can be presumed to be of a single polymer ty,pe. It can be assumed that ECA and MVK copolymerized. Fig. I illustrates the dependence of copotymer composition on the feed ratio. The copolymer compositions were determined from the infrared and NMR spectra. The monomer reactivity, ratio of ECA (Mr) with MVK (M2) was determined by the Fineman-Ross method 2 in accordance with Fig. 1. The results are as follows: rl = 2.67 and r~ = 0.14. The Q-e values of ECA (Mi) and MVK (M 2) were calculated with these results: Ql = 9.68, Q2 = 0.69. el = 1.67 and e2 = 0.683. Table 2 shows the softening points and the adhesive strengths of the copolymers. The softening point rises as the MVK concentration increases, indicating that the rise in softening point results from the copolymerization of ECA and MVK, as well as from an
Table 2. strength
Softening points of polymers and adhesive
Specimen No.
ECA (feed molar fraction)
Softening point (°C)
Adhesive strength
(kg cm-2) ~ 10
1.00
160~
11
0.81
172 ~ 180
171
12 13 14 15 16 17
0.69 0.62 0.49 0.41 0.29 0.20
175 ~ 185 1 7 0 ~ 180 183~200 201 ~ 2 1 3 205~215 210~217
81 +__2 59__+ 5 54__+ 7 25__+8 12__+2 6 __+1 2__+ 1 --
~lap area = 0.4 cm 2 (2 cm x 0.2 cm); number of test pieces = 5
increase in molecular weight. Modes of failure for samples given in Table 2 were: No. 10. interfacial: Nos 11 and 12, cohesive and Nos 13-16, intrafacial. With sample No. 17 failure was interfacial and the strength was very low. As an alternative to applying a mixture of ECA and MVK monomers to PVC substrates in the assembly of adhesive bonds, the copolymers were also used as solution polymers in acetone. It was only with polvethvlcyanoacrylate that a joint strength (of 0.0c) kg cm -2) could be measured. In other cases the copolymers peeled from the adherend as the acetone evaporated. Conclusions The m o n o m e r reactivity, ratios for ECA and MVK were: rj = 2.67. and r~ = 0.14. F r o m these two values, the
values of Q-e were calculated: Q1 = 9.68, e I 1.67, and Q2 = 0.69, e~ = 0.68. The addition of MVK improves the heat resistance of E('A, but lowers adhesion. =
Acknowledgement
o L. o o O o o
._g X
0.5
0
This study was first published in the minutes of meeting No. 24 of the Adhesion Study Group of" the Japanese Adhesion Association in Osaka on 13 June,
//
1986.
References 1
"AdhesionHandbook" (The Japan Adhesion Association, Nikkan
2
Fineman. M. andRoas, S.D. JPolymSciS(1950) p259
3
Brandrup, J. and Immergut, E.H. (eds) "Polymer Handbook' (Interscience, 1966)
Kogyo Shimbunsha) (1980)
Authors I 0
0.5
Molar fraction cyonoacrylote in feed Fig. 1 Dependence of the copolymer composition on feed ratio: ©, determined by infrared spectroscopy; and A, determined by NMP spectroscopy
144
INT.J.ADHESION AND ADHESIVES JULY 1 9 8 9
Kazushi Maruyama. Yoshio Tsushima, Tomohiro Kuramochi and Masaru Ibonai are with the Department of Industrial Chemistry, Kogakuin University 2665-1, Nakano-machi, Hachiouji-shi, 192, Japan. Kouji Nagasawa is with Taoka Chemical Industries, Ltd., 2-I 1 Nishimikuni, 4-chome, Yodogawa-ku, Osaka-shi, 532, Japan. Correspondence should be addressed to M. lbonai.