Synthesis and Cure Kinetics of Resol Type Phenolic Resin/Layered Silicate Nanocomposite

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Synthesis and Cure Kinetics of Resol Type Phenolic Resin/Layered Silicate Nanocomposite

Ho-Yun Byun, Min-Ho Choi and In-Jae Chung^†

Department of Chemical Engineering,

Korea Advanced Institute of Science and Technology, 373-1, Kusong-dong, Yusung-gu, Daejeon 305-701, Korea (Received 19 June 2001; accepted 3 August 2001)

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Abstract−Resol type phenolic resin/layered silicate nanocomposites(RPLSNs) were prepared by melt intercalation method and the cure kinetics was studied as a function of the amount of layered silicate. The partially exfoliated structure was found below 3 wt% of layered silicate, while more stacked silicates were found at 5 wt% of layered silicates. The result of FTIR experiment for cure reaction of phenolic resin showed that the RPLSN had almost the same activation energy as pristine phe- nolic resin but it had 7 times lower frequency factor than pristine phenolic resin as the amount of layered silicate increased.

Therefore, the steric hindrance of layered silicate in the nanocomposite affected the cure kinetics and disturbed the formation of three dimensional network structure of phenolic resin during cure reaction.

Key words: Resol Type Phenolic Resin, Layered Silicate, Nanocomposite, Cure Kinetics

1. B †

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†To whom correspondence should be addressed.

E-mail: chung@cais.kaist.ac.kr

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«~&.

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¢ šÏ~ 110^oCöB 1*ÿn ãz>wj V.  ê 130^oCöB 1* ÿn convection ovenöB êãz(postcuring)¢ B .ž; ¾

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=

Fig. 1. X-ray diffraction patterns of (a) MMT and (b) C6M.

thylene ether bridge¾ methylene bridge‚ ÖB RÒ^¢ ò²

methylol group

GPC¢ šÏ~ ’‚ KL>æ~ >ï ª¶ï Mnf 1,026, Z² ï

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Fig. 2. Solid-state ¹³C CP/MAS NMR spectrum of phenolic resin. Asterisk indicates spinning sideband.

Fig. 3. MALDI-MS spectrum of phenolic resin.

Fig. 4. X-ray diffraction patterns of (a) KLMMT and (b) KLC6M cured at 110^oC for 1 hr followed by curing at 130^oC for 1 hr as a function of silicate content.

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ö  b’& ¾æ¾–, ª¶& Ò&šÞ~ [*ö ã«>Ú [*

–Ò¢ {Ëʚ (001)š~ b’& &'öB ¾æ¾² B. š ’

–¢ ã«;(intercalation)š¢ ö~–, [璖& 2Z>Ú XRDç

~ Ò&šÞº ;Ò> ¢¦ ã«Nj r > ®, 5 wt%öBº b

j r > ®.

Fig. 5

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>wVj r~ *ö Vž FTIR Ê¿Þ"š. >ÖzV~ stretching

‡>Zº 3,330 cm⁻¹š–, z2V~ stretching ‡>Zº 2,900- 2,800 cm⁻¹š. 1,100 cm⁻¹ö methylol group~ stretching ‡>Z¢

6‚ {ž† > ®. ÊFç~ C-H Z~ deformation vibration~ ‡

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~ ‡>b’~ ^V& 6²~æ‚ š ~ b’ ’V æz¢ šÏ~ >

w~ *~Nj ’† > ®. ÊFç~ C-C Z~ deformation vibration f 1,500-1,400 cm⁻¹öB ‡>b’& ¾æ¾–, š f >wö ^

~æ pbæ‚ >wš ê¯Nö V¢ b’ ’V~ æz& ìÚ¢ ~æ ò, B‚º –.O 6²~º–,  šFº >wš ê¯Nö V¢ þ2

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f þ2 vþ¢ æzB G;‚ ‡>b’~ JN¢ FB~² B. š

 JN¢ B–~V *š  þöBº 1,481 cm⁻¹~ C-C Z~ ‡

Fig. 5. TEM micrographs of (a) KLMMT3, (b) KLC6M3, (c) KLMMT5 and (d) KLC6M5 cured at 110^oC for 1 hr followed by post-curing at 130^oC for 1 hr.

>b’¢ internal standard‚ F~&, ãz *ö &Ë ‡>b’& – (1,2-disubstituted, 1,2,6-trisubstituted)

j šÏ~ êÖ~&. 1,481 cm⁻¹ *~~ b’f 756 cm⁻¹ *~~ b

’º Lambert-Beer’s law¢ Vž. V¢B, Lambert-Beer’s law¢ šÏ

~ b’ ’Vö V¢ *~Nj ’~&.

(2)

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Fig. 7f Fig. 6~ Ö"f  (2)¢ šÏ~ áf KL>æf KLC6M5

~ Nêf *ö Vž *~N ¾*š. *Nê 'öB ¾ž

Ò&šÞ~ Î&‚ žš ¾¦>æ~ ãz>wš £* ¶Jöj .G

† > ®. ãz³êç>(curing reaction rate constant) k¢ ’~V *

š r" ?š nNj ê«~& ãz³ê ç>º Arrhenius j

(3)

k=k_o exp(−E_a/RT) (4)

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k₀º nꞶ(frequency factor)¢ ¾æÞ. 6‚ >wN>& 2N¢

 &;~, (3)j 'ª~š,

α/(1−α)=kt+C (5)

VB Cº 'ªç>š.

Fig. 8f ¾¦>æ 130^oCöB α/(1−α) vs. t~ âb‚, vitrification

pointš*~ .V F;'ž ¦ªòj ê‚ ©š. ¾¦>æº .Vö

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& ’² Ã&~, mobility& ’² 6²~ diffusion controlled >w

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~ ’‚ tanδ Ö"š. tanδ b’~ ‚&6öB~ NꂦV ª

¶~ FÒ*šNê(Tg)¢ G;~&. Fig. 11f KL>æ~ 130^oCöB ãz*ö Vž Tg~ æz¢ ê‚ ©b‚ &Û 11.14ªš vitrification pointªj r > ®î. š Ö"º Fig. 9öB ãz³ê& –~ 0š >

º vitrification pointf –~ ¢~Žj r > ®. V¢B vitrification α 1 A₁⁄A₂

A⁰₁⁄A⁰₂ ---

– 1 A

A⁰ --- –

= =

A⁰₁ A⁰₂

dα

---dt =k 1( –α)ⁿ

Fig. 6. FTIR spectra of (a) cure behaviors of KLC6M5 at 130^oC and (b) magnified peak at the region of 700-850 cm⁻¹ in (a).

Fig. 7. Conversions of (a) KL and (b) KLC6M5 as a function of temperature and time.

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. âj š vitrification pointš*öBº α/(1-α) vs. t& F;'š

–, š º*öBº ¾¦>æ~ >wš 2Nj ò—Žj r > ®. 6

‚ ¾žÚê vitrification pointÚöB 2Nj ò—Žj r > ®î

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 (4)öB š nꞶf ‚Wzö.æ‚ ’W>º–, ‚Wzö.

æº "‚ >wb" *š ç*~ ö.æN¢ ö~–,  ’V& š>

Fig. 8. Plots of α/(1−α) against curing time for (a) KL and (b) KLC6M5 at 130^oC.

Fig. 9. Plots of the curing reaction rate α/(1−α) against time for (a) KL and (b) KLC6M5 cured at 130^oC.

Fig. 10. Tan δ vs. temperature plots of KL partially cured at 130^oC as a function of time.

Fig. 11. T_g behavior of KL cured at 130^oC as a function of curing time.

ƒ ¸f ö.æ Ëã r^ö >wö ^~º >wb~ ·š ·j >w

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nꞶº >wb Қ~ Ïònê¢ ~~–,  ’V& š>ƒ >

KLC6M5

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ÚöB [* Ú~ ‚Wzö.æ& [ <öB~ ‚Wzö.æ z

šÞ‚ ž‚ «Úˆ r^ö B>‚ >æö jš Ô~. Tyan [27]

6‚ poly(amic acid)~ šz ";öB B>‚ Қ(polyimide)

3. Ö †

.ž; ¾¦>æ¢ šÏ~ .ž; ¾¦>æ/[çÒ&šÞ ¾ž

Ú¢ Ï[ ã«»b‚ B–~&. ãzÊV*~ KL>æº NMR j ۚ ‚>Wj &æº methylol groupj ŽF~ ®b–, MALDI- MS

XRDf TEMj ÒÏ~ .ž; ¾¦>æ/[çÒ&šÞ ¾ž

Ú~ Î‚æ¢ {ž‚ Ö" Ò&šÞ~ ‚š~ Bî" ç&ìš

3 wt%

šÞ~ ·š Ã&®rj r > ®î. V¢B, ¾¦>æ~ [* ã«ö Fig. 12. Linear plots of α/(1−α) against curing time for (a) KL and (b)

KLC6M5 as a function of curing temperature and time.

Table 1. Curing reaction rate constants of KL and KLC6M5 for various curing temperatures

Curing temperature(^oC) KL KLC6M5

k^a) C^b) R^c) k^a) C^b) R^c)

190 0.013 0.017 0.9921 0.010 0.022 0.9875

100 0.026 0.014 0.9971 0.023 0.011 0.9986

110 0.061 0.007 0.9978 0.048 0.001 0.9987

130 0.216 -0.025- 0.9996 0.149 -0.020- 0.9996

150 0.645 0.111 0.9890 0.428 -0.074- 0.9899

a)Curing reaction rate constant(min⁻¹). ^b)Constant. ^c)Relative deviation from the perfect linearity(the value of unity).

Fig. 13. Arrhenius plot of the reaction rate constant(lnk) against 1,000/

T for KL and KLC6M5.

Table 2. The activation energy and frequency factor of KL and KLC6M5 Sample E_a(kcal/mol) k_o(min⁻¹)

KL 20.19 1.81810¹⁰

KLC6M5 18.95 2.75710⁹⁰

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^^ò

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